No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Degradation of polysaccharides by intestinal bacterial enzymes
Abstract
Polysaccharides with structures resembling components of dietary fiber were fermented by a number of species of anaerobic bacteria from the human colon. Some strains also fermented glycoprotein mucins. The strains that fermented the widest range of polysaccharide substrates were in the two genera Bacteroides and Bifidobacterium. Polysaccharide degrading enzymes from several Bacteroides species have been studied, and in most cases the enzyme activities were cell bound rather than extracellular. In all cases, the polysaccharide degrading enzymes were inducible rather than constitutive. Thus the metabolic activity of the flora could be altered considerably by the amount and type of fiber in the diet, even though the composition of the flora itself remained unchanged. The products of enzyme action included monosaccharides and oligosaccharides of varying chain lengths.
... Fermentation of guar gum produces short-chain fatty acids and gases such as carbon dioxide, hydrogen, and methane (Mali et al., 2012). Salyers et al. (1977 and1978) studied the degradation of guar gum by anaerobic microorganisms. They found that Bacteroides ovatus, Bacteroides '0061-1,' and Bacteroides vulgatus ferment guar gum. ...
... The carbon-nitrogen particles may be a product of microbial activity fixing nitrogen from the air to organic products, or a contaminant from the Struers cooling fluid used to cut the samples. Previous microbial research does not indicate that microbes consume atmospheric nitrogen when in contact with guar gum (Salyers et al., 1977;Salyers et al., 1978;Hartemink et al., 1999). Mariotti et al. (2001) studied whether guar gum could affect the absorption of nitrogen in the digestive tracks of larger organisms and concluded that guar gum had no noticeable effect. ...
The Marcellus shale, located in the mid-Atlantic Appalachian Basin, has been identified as a
source for natural gas and targeted for hydraulic fracturing recovery methods. Hydraulic
fracturing is a technique used by the oil and gas industry to access petroleum reserves in geologic formations that cannot be accessed with conventional drilling techniques (Capo et al., 2014). This unconventional technique fractures rock formations that have low permeability by pumping pressurized hydraulic fracturing fluids into the subsurface. Although the major components of hydraulic fracturing fluid are water and sand, chemicals, such as recalcitrant biocides and polyacrylamide, are also used (Frac Focus, 2015).
There is domestic concern that the chemicals could reach groundwater or surface water during transport, storage, or the fracturing process (Chapman et al., 2012). In the event of a surface spill, understanding the natural attenuation of the chemicals in hydraulic fracturing fluid, as well as the physical and chemical properties of the aquifers surrounding the spill site, will help mitigate potential dangers to drinking water. However, reports on the degradation pathways of these chemicals are limited in existing literature.
The Appalachian Basin Marcellus shale and its surrounding sandstones host diverse
mineralogical suites. During the hydraulic fracturing process, the hydraulic fracturing fluids
come into contact with variable mineral compositions. The reactions between the fracturing fluid chemicals and the minerals are very diverse. This report: 1) describes common minerals (e.g. quartz, clay, pyrite, and carbonates) present in the Marcellus shale, as well as the Oriskany and Berea sandstones, which are located stratigraphically below and above the Marcellus shale; 2) summarizes the existing literature of the degradation pathways for common hydraulic fracturing fluid chemicals [polyacrylamide, ethylene glycol, poly(diallyldimethylammonium chloride), glutaraldehyde, guar gum, and isopropanol]; 3) reviews the known research about the interactions between several hydraulic fracturing chemicals [e.g. polyacrylamide, ethylene glycol, poly(diallyldimethylammonium chloride), and glutaraldehyde] with the minerals (quartz, clay, pyrite, and carbonates) common to the lithologies of the Marcellus shale and its surrounding sandstones;1 and 4) characterizes the Berea sandstone and analyzes the physical and chemical effects of flowing guar gum through a Berea sandstone core.
... Meanwhile, CPs have been shown to be promising drugs for the treatment of various diseases and functional components in food preparations. It has also been proved that polysaccharides are primarily digested in the intestine and degraded by gut microbiota; thus, the intestine is the major target organ of CPs [23]. Moreover, CPs have fewer side effects and lower cytotoxicity and are thus allowed for long-term use [24]. ...
Aging is a biological process that leads to the progressive deterioration and loss of physiological functions in the human body and results in an increase in morbidity and mortality, and aging-related disease is a major global problem that poses a serious threat to public health. Polysaccharides have been shown to delay aging by reducing oxidative damage, suppressing inflammatory responses, and modulating intestinal microbiota. Our previous studies have shown that polysaccharide CPP-1 extracted from the root of Codonopsis pilosula possesses noticeable anti-oxidant activity in vitro. Thus, in our study, we tested the anti-aging effect of CPP-1 in naturally aging mice (in vivo). Eighteen C57/BL mice (48-week-old, male) were divided into a control group, high-dose CPP-1 group (20 mg/mL), and low-dose CPP-1 group (10 mg/mL). We discovered that CPP-1 can exert a reparative effect on aging stress in the intestine and liver, including alleviating inflammation and oxidative damage. We revealed that CPP-1 supplementation improved the intestinal microbiota composition and repaired the intestinal barrier in the gut. Furthermore, CPP-1 was proved to modulate lipid metabolism and repair hepatocyte injury in the liver by influencing the enterohepatic axis associated with the intestinal microbiota. Therefore, we concluded that CPP-1 prevents and alleviates oxidative stress and inflammatory responses in the intestine and liver of aging mice by modulating the intestinal microbiota-related gut-liver axis to delay aging.
... and Bifidobacterium spp. have been shown to produce inducible intracellular enzymes that degrade various polysaccharides [68]. If strains of Lactobacillus spp. ...
The current paper provides a review and meta-analysis of the practical implications of disaster risk management related to the ventilated improved latrines in South Africa. This technology is evaluated through its legacy and novel challenges of disaster risk reduction. In the current article, the methodology adopted was a literature review and meta-analyses. The results indicate that the in-situ treatment and breakdown of faecal sludge in the ventilated improved pit latrines is not always taking place and that anaerobic digestion might not always be feasible. New strategies are proposed to manage the sanitation-related risks in South Africa by specifying more exact dimensions for the newly built ventilated improved pit latrines by suggesting the use of novel sanitation additives such as fly ash to enhance on-site and in situ treatment, as well as ex situ treatment of the pit latrine faecal sludge. Regular maintenance can lead to prevention of the dysfunctional character of the ventilated improved pit latrines as a functional sanitation technology and a user-friendly hygiene barrier to the spread of sanitation/WASH-related epidemics or infectious diseases. The implementation of the novel strategies should be enhanced by the application of the (Environ-mental) Technology Assessment in sanitation service delivery in South Africa.
... The bifidobacterial growth factors in the human milk were assigned to a group of N-acetylglucosamine-containing oligo-and polysaccharides (Gauhe et al., 1954), currently named human milk oligosaccharides (HMO). Soon after, polysaccharides from dietary fiber and fructooligosaccharides (FOS) were described as non digestible and not absorbed in the small intestine and to increase human gut bifidobacteria (Nihimoto, 1984;Salyers et al., 1978). Commercialization of FOS obtained either by enzymatic transfructosylation of sucrose or by hydrolysis of inulin, started in the 1980s (Nihimoto, 1984). ...
Probiotics, prebiotics and synbiotics are well known by the dedicated research studies on them and as commercial products. More recently, a number of “biotic” preparations have emerged with different prefixes and they refer to their nature and formulation (“post-”, “para-”) or they are related to their health effect (“psycho-”, “gero-”, “immuno-”, etc.). So far, numerous probiotics and prebiotics have sound scientific evidences supporting their health effects, but they are not matching with their regulatory status. Despite that, scientific studies are outlining the new trends in this field, like research on new-generation probiotics and prebiotics and well-characterized postbiotics. Future research should focus on sound clinical trials and compositional and mechanistic characterization of these preparations.
... Laminarans were highly fermented by human faecal bacteria with a short delay in the gas production phase. Such a latency phase has already been reported for fermentation of laminarans by isolated Bacteroides strains and has been attributed to the time required for the induction of the specific @-glucanases to occur (Salyers et al. 1977a(Salyers et al. , 1978. These authors also observed that laminarans were degraded into monomeric glucose and laminaro-oligosaccharides (degree of polymerization between 2 and 6). ...
The in vitro degradation of dietary fibre from three brown seaweeds (Himanthalia elongata, Laminaria digitata and Undaria pinnatiJda) was studied, using human faecal flora. Two sets of fibre were tested: (1) total algal fibres extracted from the whole algae, mainly composed of alginates, and (2) purified fibres (sulphated fucans, Na-alginates and laminarans) representative of those contained in the whole brown algae. Mannuronate, one algal component, was also investigated. Substrate disappearance and short- chain fatty acid (SCFA) production were monitored after 6, 12 and 24 h fermentation. Gas production was followed hourly during the first 9 h and then at 12 and 24 h. Sugarbeet fibre was used as a fermentation reference substrate. According to the fermentative indices used, most of each of the total algal fibres disappeared after 24 h (range 60–76 %) hut, unlike the reference substrate, they were not completely metabolized to SCFA (range 47–62 %). Among the purified algal fibres, disappearance of laminarans was approximately 90% and metabolism to SCFA was approximately 85% in close agreement with the fermentation pattern of reference fibres. Sulphated fucans were not degraded. Na- alginates exhibited a fermentation pattern quite similar to those of the whole algal fibres with a more pronounced discrepancy between disappearance and production of SCFA: disappearance was approximately 83 % but metabolism was only approximately 57 YO. Mannuronate was slowly fermented hut its metabolism corresponded to its disappearance from the fermentative medium. Thus, the characteristic fermentation pattern of the total fibres from the three brown algae investigated was attributed to the peculiar fermentation of alginates, and mannuronate was shown not to be directly involved.
... In recent reports, truffle polysaccharides were identified as natural antioxidants that have essentially no side effects compared to synthetic antioxidants [6,21,22]. Given that most of the polysaccharides cannot be degraded by mammalians but by intestinal microbiota, it is reasonable for the intestine to be the major target organ of polysaccharides [19,23]. However, few studies have shown the effects of truffle polysaccharides on intestinal oxidative stress. ...
Truffles are world-renowned premium commodities. Due to their unique aroma and rarity, the price of truffles has always been very high. In this study, Diethylaminoethyl anion exchange chromatography and gel filtration were employed for polysaccharide purification from two different species of Chinese truffles. Three polysaccharide fractions were obtained from Tuber panzhihuanense and referred to as TPZ-NP, TPZ-I, and TPZ-II. Additionally, two polysaccharide fractions were purified from T. pseudoexcavatum (TPD-NP and TPD-I). The results of structural elucidation indicated that the polysaccharide from different species showed different monosaccharide composition and linkage units, as well as molecular weight. Two of the polysaccharide fractions with the highest yield, TPZ-I and TPD-I, were chosen for biological testing. The results indicated that both fractions displayed antioxidant properties through mediation of the intestinal cellular antioxidant defense system, which could protect cultured intestinal cells from oxidative stress-induced damage and cell viability suppression. The TPD-I fraction showed stronger antioxidant effects, which may be due to the difference in structure. Further study on the structure-activity relationship is needed to be done.
... Brown seaweed is of particular interest as it contains polysaccharides such as fucoidan, laminarin and alginate which are all reported to have impacts on gut health. Alginate is generally fermented by a specific gut bacterium, Bacteroides ovatus (Salyers, Palmer, & Wilkins, 1978). Apart from B. ovatus, alginate is also used by other bacteria in the gut. ...
Seaweeds and their bioactive compounds, particularly polysaccharides and phenolics can be regarded as great dietary supplements with gut health benefits and prebiotics. These components are resistant to digestion by enzymes present in the human gastrointestinal tract, also selectively stimulate the growth of beneficial gut bacteria and the production of fermentation products such as short chain fatty acids. Commonly, the health benefits of seaweed components are assessed by including them in an in vitro anaerobic fermentation system containing human fecal inocula that mimics the environment of the human large bowel. Regarding to the complex interactions between dietary components, gastrointestinal physiological processes, and gut microbiota are difficult to model in vitro. Consequently it is important to follow up the promising in vitro results with in vivo animal or human testing. The aim of this chapter is to have a comprehensive review on the application of seaweeds and seaweed-derived metabolites as prebiotics, and understand the trends, gaps and future directions of both scientific and industrial developments. This work contributes to develop and expand new platform of seaweed utilization for higher-value products, particularly to functional food and nutraceutical industries in order to serve the social demand for health awareness and support economic development.
... Thus, the addition of hydrophobic polyol to the guar gum matrix will protect the drugs in the gastric liquid (pH 1.3-3.5) and the resulting hydrogels act as a site-specific delivery system, in which the degradation of guar gum component by the colonic microflora [47] may allow for the release of the drug at a niche where the hydrogel shows high swelling. The introduction of naturally occurring biodegradable polymers like chitosan, guar gum, and linseed oil-based polyol has led to environmentally friendly and commercially fruitful products. ...
This research work deployed free radical polymerization for the development of pH-responsive hybrid nanocomposite hydrogels (NCHs) with the formation of improved interpenetrating networks (IPN). The crosslinked biopolymeric system was composed of (chitosan (CH)/guar gum (GG)/polyol) and a nanofiller (Cloisite 30B). The study was aimed to investigate the role of Cloisite 30B as a nanofiller and linseed oil-derived polyol to induce stable interpenetrating networks in chitosan‒guar gum-based hydrogels. FT-IR analysis confirmed the formation of crosslinked networks with the formation of hydrogen bonds in the synthesized NCHs. Thermogravimetric analysis and differential scanning calorimetry revealed high thermal stability of the NCHs. The hydrolytic and soil burial degradation tests confirmed the biodegradability of the synthesized NCHs. An extraordinarily high swelling capacity in a buffer solution of pH 4.0 and 7.4 demonstrated their pH-responsive behavior. It has been demonstrated that even the minimal addition of polyol to the guar gum-based hydrogels has influenced the stability and characteristic features such as high swelling capacity owing to the formation of interpenetrating networks and the biodegradability of the hydrogels.
... The viability of probiotic culture was confirmed by intermittent sampling throughout the dissolution course and the bacteria in the probiotic culture were found to be viable as indicated turbidity in vials after the incubation period under anaerobic conditions. Guar gum matrix was completely degraded by enzymes generated [59][60][61] by the bacteria in the probiotic cultures and was able to release more than 80% of drug at the end of 8 hours. It can be concluded that probiotic cultures can be used as a biorelevant media to simulate colonic conditions to evaluate drug release from polysaccharide-based colonic formulations. ...
Background
We report the effectiveness of a targeted delivery system containing Meloxicam using polysaccharides for the treatment of colorectal cancer. We also propose a novel biorelevant dissolution method to overcome drawbacks of existing dissolution methodologies of polysaccharide-based systems. The proposed method includes a mixture of probiotics cultured under anaerobic conditions in presence of prebiotic in the in vitro dissolution study to surrogate colonic conditions. Polysaccharide-based system can be simple, safe and effective drug delivery system to target drugs to colon.
Methods
Press-coated tablets of Meloxicam were prepared by direct compression using various polysaccharides such as xanthan gum, guar gum and pectin as coating polysaccharides. Developed tablets were evaluated for physical parameters, lag phase and in vitro drug release. Developed probiotics-based dissolution method was validated and explored for versatility using other polysaccharides.
Results
Press-coated tablets of Meloxicam were successfully developed exhibiting targeted delivery to the colon using guar gum as coat and releasing more than 80% of drug in simulated colonic fluid. The developed probiotics based dissolution method may prove to be useful as a bio-relevant and discriminatory method.
Conclusion
Developed Meloxicam tablets press-coated with guar gum can be taken orally for treatment or as an adjuvant therapy in colon cancer. Polymers used in this formulation are abundant, nontoxic, biodegradable and inexpensive which make this as a very promising approach for treatment of different colonic diseases. The proposed biorelevant, animal sparing, probiotics based dissolution medium was found versatile to study drug release from other polysaccharide based formulations for colonic delivery.
... Данные микроорганизмы способны продуцировать большое количество ферментов, участвующих в расщеплении различных типов углеводов, что позволяет микроорганизмам приспосабливаться и конкурировать в среде с изменяющимся пищевым составом (Рalframan et al., 2003;Ventura et al., 2007a, b). Благодаря наличию специфических ферментов бифидобактерии способны ферментировать амилозу, амилопектин, полигалактуронаны, гуммиарабик и использовать их в питании (Salyers et al., 1978;Palframan et al., 2003). Ранее показано, что при культивировании бифидобактерий на различных углеводсодержащих субстратах изменяется их ферментативная активность (Wang, Gibson, 1993;Рalframan et al., 2003;Ventura et al., 2007a, b;Goulas et al., 2009). ...
Ability of the bifidobacteria metabolites to break down the sodium alginate molecules is shown for the case of alginate-containing biogel from brown algae with 0.2 % of sodium alginate and the metabolites of bifidobacteria cultured on the semisolid Blaurock media in presence of this biogel. The allocated metabolites caused enzymatic degradation of alginic acids: the lower the alginic acids concentration, the higher the rate of degradation. Effectiveness of the bifidobacteria metabolites to split the sodium alginate depended on stage of the microorganisms development. The samples incubated with metabolites in the stationary phase of growth had viscosity of the polysaccharide solution reduced in 23.0 %, and those incubated in the phase of cell death - in 43.8 %, with the molecular mass of polysaccharide decreased in 1.8-2.0 times. Mechanisms of the sodium alginate utilization by bifidobacteria are discussed.
... Although both alginate and laminarin are derived from brown algae, they are structurally different in chemical structure and physical properties. Therefore, variations in fermentability of these two polysaccharides may occur (Salyers, Palmer, & Wilkins, 1978). compared the fermentability of laminarin and alginate by the gut microbiota of Wistar rats. ...
The gut microbiota that resides in the mammalian intestine plays a critical role in host health, nutrition, metabolic and immune homeostasis. As symbiotic bacteria, these microorganisms depend mostly on non-digestible fibers and polysaccharides as energy sources. Dietary polysaccharides that reach the distal gut are fermented by gut microbiota and thus exert a fundamental impact on intestinal ecology. Marine polysaccharides contain a class of dietary fibers that are widely used in food and pharmaceutical industries (e.g., agar and carrageenan). In this regard, insights into fermentation of marine polysaccharides and its effects on intestinal ecology are of vital importance for understanding the beneficial effects of these glycans. Here, in this review, to provide an overlook of current advances and facilitate future studies in this field, we describe and summarize up-to-date findings on how marine polysaccharides are metabolized by gut microbiota and what effects these polysaccharides have on intestinal ecology.
... In addition, micromoles per gram of butyrate, acetate, and propionate all tended to decrease with psyllium intake while remaining unchanged in the SM groups; however, we acknowledge that these changes were not significant. Salyers et al. [32] suggest that psyllium may be fermentable because of the presence of arabinoxylans, but the complex nature of these highly branched arabinoxylans [33] may cause incomplete fermentation of psyllium with little or no effect on SCFA production. The lack of fermentibility or incomplete and limited fermentibility of psyllium is supported by our findings as well as prior studies in humans in which intestinal gas is not increased with psyllium intake, indicating a lack of fermentable properties [6,34,35]. ...
Approximately one-third of individuals in the United States experience unsatisfactory bowel habits, and dietary intake, especially one low in fiber, could be partly responsible. We hypothesized that intake of a fermentable fiber (starch-entrapped microspheres, SM) that has a delayed, slow fermentation profile in vitro would improve bowel habit while exhibiting prebiotic capacity in those with self-described unsatisfactory bowel habits, all with minimal side effects. A total of 43 healthy volunteers completed a 3-month, double-blind, parallel-arm randomized clinical trial to assess the ability of a daily dose (9 g or 12 g) of SM versus psyllium (12 g) to improve bowel habit, including stool consistency and frequency, and modify gut milieu through changes in stool microbiota and short-chain fatty acids (SCFAs), while remaining tolerable through minimal gastrointestinal symptoms. All outcomes were compared before and after fiber treatment. Stool frequency significantly improved (P = .0003) in all groups after three months, but stool consistency improved only in both SM groups compared to psyllium. In addition, all groups self-reported a similar improvement in overall bowel habit with fiber intake. Both SM and psyllium resulted in minimal changes in microbiota composition and SCFA concentrations. The present study suggests that supplementation with a delayed and slow-fermenting fiber in vitro may improve bowel habit in those with constipation, but further investigation is warranted to determine capacity to alter microbiota and fermentation profiles in humans. This trial was registered at ClinicalTrials.gov as NCT01210625.
... Several studies have demonstrated the degradation of polysaccharides from brown seaweeds in the human gastrointestinal tract. Salyers et al. (1978) reported that species of Bacteroides can induce production of enzymes which degrade laminarin and alginate. Bacteroides distasonis, Bacteroides thetaiotaomicron, and Bacteroides group B0061^are able to break down laminarin to glucose (G1) and higher oligomers (G2-G6), while Bacteroides ovatus is involved in alginate degradation. ...
This study aimed to understand the prebiotic potential and contribution of four extract fractions from the brown seaweed Ecklonia radiata. Four seaweed fractions were tested for their digestibility and prebiotic effects using an in vitro anaerobic fermentation system containing human faecal inocula. After 24 h fermentation, three seaweed fractions, except the phlorotannin-enriched fraction (PF), significantly increased (P < 0.05) total short chain fatty acid (SCFA) production (68.9–97.3 μmol mL⁻¹) compared to the negative controls comprising either of a blank (36.3 μmol mL⁻¹) or cellulose (39.7 μmol mL⁻¹). The low molecular weight (MW) polysaccharide-enriched fraction (LPF) stimulated the growth of beneficial bacteria including Bifidobacterium, Lactobacillus, and Clostridium coccoides. The high MW polysaccharide-enriched fraction (HPF) showed the greatest potential for improving gut health as this fraction was not digestible by enzymes present in the small intestine, and induced significantly higher butyric acid production (8.2 μmol mL⁻¹) than the positive control, inulin (2.3 μmol mL⁻¹). These findings further demonstrate that E. radiata-derived polysaccharides have the potential to be used as dietary supplements with gut health benefits, worthy of further in vivo studies.
... An initial observation that obesity affects the relative abundance of Firmicutes (Gram-positive) and Bacteroidetes (Gram-negative) taxa has not been replicated, but many of these studies were limited in sample size and often failed to separate the effects of obesity and diet composition (68)(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83). For example, taxa in the Bacteroidetes phylum utilize fiber for growth and therefore would be expected to be decreased with high fat, low fiber diets (84,85). ...
Obesity increases the risks of many cancers. One important mechanism behind this association is the obesity-associated pro-inflammatory state. Although the composition of the intestinal microbiome undoubtedly can contribute to the pro-inflammatory state, perhaps the most important aspect of host-microbiome interactions is host exposure to components of intestinal bacteria that stimulate the inflammatory reactions. Systemic exposures to intestinal bacteria can be modulated by dietary factors by altering both the composition of the intestinal microbiota as well as absorption of bacterial products from the intestinal lumen. In particular, high fat and high energy diets have been shown to facilitate absorption of bacterial lipopolysaccharide (LPS) from intestinal bacteria. Biomarkers of bacterial exposures that have been measured in blood include LPS-binding protein, sCD14, fatty acids characteristic of intestinal bacteria and immunoglobulins specific for bacterial LPS and flagellin. The optimal strategies to reduce these pro-inflammatory exposures, whether by altering diet composition, avoiding a positive energy balance or reducing adipose stores, likely differ in each individual. Biomarkers that assess systemic bacterial exposures therefore should be useful to optimize and personalize preventive approaches for individuals and groups with specific characteristics, and to gain insight into the possible mechanisms involved with different preventive approaches.
... First studies performed in vitro showed that among different genus of bacteria from human faeces, bifidobacteria strains were able to use acacia gum for their growth [20]. ...
Prebiotics have great potential as agents to improve or maintain a balanced intestinal microflora to enhance health and wellbeing. They are non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract. Key to this is the specificity of microbial changes.Thanks to the methodological and fundamental research of microbiologists, enormous progress has been made in understanding the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. The concept prebiotics is to enhance the growth of beneficial bacteria in the lower intestine. There is much interest in increasing the numbers and activities of beneficial bacteria (Bifidobacteria) in the large gut, preferably at the expense of more harmfulbacteria. The focus of this review has been to point out the prebiotic effects (bifidogenic effects) of acacia gum and inulin. Some effects attributed to selected prebiotics have been proved by clinical trials, while others have been acquired on the basis of in vitro tests.
... First studies performed in vitro showed that among different genus of bacteria from human faeces, bifidobacteria strains were able to use acacia gum for their growth [20]. ...
Prebiotics have great potential as agents to improve or maintain a balanced intestinal microflora to enhance health and wellbeing. They are non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract. Key to this is the specificity of microbial changes.Thanks to the methodological and fundamental research of microbiologists, enormous progress has been made in understanding the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. The concept prebiotics is to enhance the growth of beneficial bacteria in the lower intestine. There is much interest in increasing the numbers and activities of beneficial bacteria (Bifidobacteria) in the large gut, preferably at the expense of more harmfulbacteria. The focus of this review has been to point out the prebiotic effects (bifidogenic effects) of acacia gum and inulin. Some effects attributed to selected prebiotics have been proved by clinical trials, while others have been acquired on the basis of in vitro tests.
... From these findings, bacterial remnants derived from indigenous bacteria that were killed in each intestinal segment might be digested probably by the cooperative effects of various bactericidal peptides and digestive enzymes. Enzymes and nutrients from indigenous bacteria have beneficial effects on their hosts [3,26]. Therefore, the denaturing and killing of large numbers of indigenous bacteria in the intestine might be a host's strategy to utilize bacteria-derived enzymes and nutrients. ...
Indigenous bacteria in the alimentary tract are exposed to various bactericidal peptides and digestive enzymes, but the viability status and morphological changes of indigenous bacteria are unclear. Therefore, the present study aimed to ultrastructurally clarify the degeneration and viability status of indigenous bacteria in the rat intestine. The majority of indigenous bacteria in the ileal mucous layer possessed intact cytoplasm, but the cytoplasm of a few bacteria contained vacuoles. The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine. In the dividing bacteria of the mucous layer and chyme throughout the intestine, the ratio of area occupied by vacuoles was almost always less than 10%. Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine. In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed. From these findings, indigenous bacteria in the mucous layer were ultrastructurally confirmed to be the source of indigenous bacteria in the chyme. Furthermore, the results suggested that indigenous bacteria were more severely degenerated toward the large intestine and were probably degraded in the intestine.
... The ability to degrade mucin seems to be limited to particular gut commensals, such as certain species of Bacteroides, Bifidobacterium, Ruminococcus and Akkermansia [20,26,[66][67][68]. Pathogenic bacteria appear to be poorly adapted to mucin degradation [69], however, multiple studies have shown pathogens utilizing constituents of mucin released by commensal glycosidases. ...
Background
Bifidobacteria constitute a specific group of commensal bacteria that commonly inhabit the mammalian gastrointestinal tract. Bifidobacterium breve UCC2003 was previously shown to utilize a variety of plant/diet/host-derived carbohydrates, including cellodextrin, starch and galactan, as well as the mucin and HMO-derived monosaccharide, sialic acid. In the current study, we investigated the ability of this strain to utilize parts of a host-derived source of carbohydrate, namely the mucin glycoprotein, when grown in co-culture with the mucin-degrading Bifidobacterium bifidum PRL2010.Results B. breve UCC2003 was shown to exhibit growth properties in a mucin-based medium, but only when grown in the presence of B. bifidum PRL2010, which is known to metabolize mucin. A combination of HPAEC-PAD and transcriptome analyses identified some of the possible monosaccharides and oligosaccharides which support this enhanced co-cultivation growth/viability phenotype.Conclusion
This study describes the potential existence of a gut commensal relationship between two bifidobacterial species. We demonstrate the in vitro ability of B. breve UCC2003 to cross-feed on sugars released by the mucin-degrading activity of B. bifidum PRL2010, thus advancing our knowledge on the metabolic adaptability which allows the former strain to colonize the (infant) gut by its extensive metabolic abilities to (co-)utilize available carbohydrate sources.
... oped to exploit the potential of the specific nature of diverse microflora associated environment with the colon compared to other parts of the GIT. Microflora present in the colon survives by fermenting the various types of substrates such as nonstarch polysaccharides, carbohydrates and fibers that have been left undigested in the small intestine. [12] The microflora of the human gastrointestinal tract consists of a coexisting mixture of aerobic and anaerobic bacteria in a complex ecosystem especially in colonic region.Targeting Abstract: Polysaccharidase producing microflora in the large intestine could facilitate the use of polysaccharides as the carriers for the drug delivery to th ...
... Band 2 was related to Bacteroides coprophilus (88% similarity) which is strict anaerobe isolated from human faces with pH 7.2 and 37°C for the growth optimum (Hayashi et al., 2007). Genus Bacteroides are able to ferment complex carbohydrate such as alginate with cell bound enzymes (Hayashi et al., 2007;Salyers et al., 1978). Indeed, the B. coprophilus-like band was detected with gradually increasing intensity during the operation and might have contributed to the hydrolysis of alginate in the process (Fig. 2). ...
... It has been reported that this method is effective in separating bacteria from soluble elements. 44 Because cell-associated enzyme systems from Bacteroides strains have been shown to degrade polysaccharides, 45 it was necessary to prepare a second enzyme mixture from the isolated bacterial pellet. The resulting bacterial pellet was washed and resuspended in the same buffer solution. ...
This paper investigates the design of novel polyelectrolyte complex (PEC) coacervates of chitosan (Ch) with gum Odina (GO) as potential candidates for colon targeting. Potentiometric titration experiments established that 1:1 charge stoichiometry occurred at a Ch/GO weight ratio of 1:5. The coacervate formed at pH 4.5 displayed the highest storage modulus (G′) values. FTIR, XPS, WAXS, TGA, and DSC results suggested the strong ionic (NH 3 + ···COO −) bond formation between these two biopolymers. Through in vitro viability tests, the pH-induced PECs were shown to be nontoxic. In vitro biodegradation rates of their microspheres revealed insolubility in simulated gastric fluid and simulated intestinal fluid and degradation by cell-associated portions of rat cecal and colonic enzymes rather than the extracellular portions. The microsphere of pH 3.0 showed the highest degradation, and LVSEM micrographs revealed notably high amount of macropores in cell-associated enzymes, in contrast to extracellular enzymes.
... It has been reported that this method is effective in separating bacteria from soluble elements. 44 Because cell-associated enzyme systems from Bacteroides strains have been shown to degrade polysaccharides, 45 it was necessary to prepare a second enzyme mixture from the isolated bacterial pellet. The resulting bacterial pellet was washed and resuspended in the same buffer solution. ...
This paper investigates the design of novel polyelectrolyte complex (PEC) coacervates of chitosan (Ch) with gum
Odina (GO) as potential candidates for colon targeting. Potentiometric titration experiments established that 1:1 charge stoichiometry occurred at a Ch/GO weight ratio of 1:5. The coacervate formed at pH 4.5 displayed the highest storage modulus (G′) values. FTIR, XPS, WAXS, TGA, and DSC results suggested the strong ionic (NH3
+···COO−) bond formation between these two biopolymers. Through in vitro viability tests, the pH-induced PECs were shown to be nontoxic. In vitro biodegradation rates of their microspheres revealed insolubility in simulated gastric fluid and simulated intestinal fluid and degradation by cellassociated portions of rat cecal and colonic enzymes rather than the extracellular portions. The microsphere of pH 3.0 showed the highest degradation, and LVSEM micrographs revealed notably high amount of macropores in cell-associated enzymes, in contrast to extracellular enzymes.
... Band 2 was related to Bacteroides coprophilus (88% similarity) which is strict anaerobe isolated from human faces with pH 7.2 and 37°C for the growth optimum (Hayashi et al., 2007). Genus Bacteroides are able to ferment complex carbohydrate such as alginate with cell bound enzymes (Hayashi et al., 2007;Salyers et al., 1978). Indeed, the B. coprophilus-like band was detected with gradually increasing intensity during the operation and might have contributed to the hydrolysis of alginate in the process (Fig. 2). ...
In this study, the response surface methodology (RSM) was applied to determine the optimum fermentative condition of alginate with the respect to the simultaneous effects of alginate concentration and initial pH to maximize the production of total volatile fatty acids (TVFAs) and alcohols. The results showed that the alginate fermentation was significantly affected by initial pH than by alginate concentration and there was no interaction between the two variables. The optimum condition was 6.2g alginate/L and initial pH 7.6 with a maximum TVFAs yield of 37.1%. Acetic acids were the main constituents of the TVFAs mixtures (i.e., 71.9-95.5%), while alcohols (i.e., ethanol, butanol, and propanol) were not detected.
In this study, the Nelumbo nucifera leaf polysaccharide (NNLP) was isolated by hot water extraction and ethanol precipitation. DEAE anion exchange chromatography and gel filtration were further performed to obtained the purified fraction NNLP-I-I, the molecular weight of which was 16.4 kDa. The monosaccharide composition analysis and linkage units determination showed that the fraction NNLP-I-I was a pectic polysaccharide. In addition, the NMR spectra analysis revealed that NNLP-I-I mainly consisted of a homogalacturonan backbone and rhamnogalacturonan I, containing a long HG region and short RG-I region, with AG-II and 1-3 linked rhamnose as side chains. The biological studies demonstrated that NNLP-I-I displayed antioxidant properties through mediating the Nrf2-regulated intestinal cellular antioxidant defense, which could protect cultured intestinal cells from oxidative stress and improve the intestinal function of aged mice.
Inulin is a heterogeneous green polysaccharide obtained from natural sources. It is found in a variety of regularly eaten vegetables, fruits, cereals, and in their roots and rhizomes including onion, leek, wheat, garlic, dahlia, asparagus, banana, chicory, etc. It has been approved by the United States Food and Drug Administration (USFDA) as a nutritional dietary supplement for infants. Recently, many researchers have given much attention to inulin and inulin-based composite for delivering drugs directly to the colon by preventing its degradation in the stomach and small intestine. However, these findings are not embodied collectively and broadly. Therefore, the present review represents to fill up these gaps in a simple way, which might help the upcoming researchers to perform more researches on inulin. This article reviews the physicochemical characteristics of inulin and its degradation by colonic microflora. In addition, this article also provides brief information on various properties of inulin when used as hydrogel and nanocarrier in delivering drugs to the colon. The various chemical modifications of inulin, conjugation with other drugs and blending it with many other biopolymers has also resulted in an enhancement of the physicochemical properties suited for colon targeting.
The role of fiber in human diet in preventing a number of chronic diseases has been a widely debated topic in recent years. The claim that populations at low risk for colon cancer generally consume a more fiber-rich diet than those at high risk, has been used to postulate a protective role for this group of substances. In this study we asked the question whether populations leading different dietary lifestyles and who are at varying risks for colon cancer show marked differences in their dietary and fecal profiles of various fiber components. Four study groups consisting of Seventh-day Adventist (SDA) pure vegetarians, SDA lacto-ovo vegetarians, SDA nonvegetarians, and a group of general population nonvegetarians were selected from the greater Los Angeles Basin area. Three-day composite diets, and stools were analyzed for neutral detergent fiber (NDF), hemi-cellulose, lignin, cellulose, cutin + silica, and pectin. The percentage composition and the daily intake and output of each of these components were computed for each population group. The dietary profile revealed a trend (not statistically significant) toward generally higher daily intake values among the vegetarian subgroups, neutral detergent fiber values in g/day: SDA pure vegetarians, 63.0 ± 7.9; SDA-lacto-ovo vegetarians, 55.8 ± 3.5; SDA nonvegetarians, 57.2 ± 3.5; general population nonvegetarians, 52.5 ± 4.9), lignin, cellulose, and pectin being the major contributors to this difference. In sharp contrast, in the stools, 24-h excretion values for NDF decreased steadily in the order, SDA-pure vegetarians, SDA-lacto-ovo vegetarians, SDA-nonvegetarians, and general population nonvegetarians (NDF values in stools in g/day: SDA-pure vegetarians, 13.8 ± 1.7; SDA-lacto-ovo vegetarians, 10.5 ± 0.8; SDA-nonvegetarians, 8.19 ± 0.7 and general population nonvegetarians, 5.05 ± 0.6). This decrease paralleled a similar drop in dry stool weight (bulk) of stools. The observations generally indicate that introduction of meat into the daily diet significantly enhances the ability of intestinal microorganisms to degrade fiber components, as reflected by the lower excretion of NDF and its constituents. From the results of the present study we conclude that under conditions of comparable intake of NDF the differences in fecal output of fiber components among the SDA and general population are a reflection of qualitative differences in the sources of plant fiber in the diet together with similar changes in microbial metabolism.
Roots and tubers are considered as the most important food crops after cereals. About 200 million farmers in developing countries use roots and tubers for food security and income. The roots and tubers contribute significantly to sustainable development, income generation and food security, especially in the tropical regions. Individually, cassava, potato, sweet potato and yam are considered the most important roots and tubers world-wide in terms of annual production. Tropical root and tubers are the most important source of carbohydrates. The nutritional composition of roots and tubers varies from place to place, depending on various factors. Physicochemical, functional and organoleptic evaluation of foods in relation to consumer preferences, life-cycle analysis of environmental impacts related to processing of tropical roots and tubers, and optimized process for reducing the anti-nutrients in tropical roots and tubers are some of the areas that need proper attention and implementation.
Food can have many effects along the gastrointestinal tract, one of which is the distension caused by the bulk of the food. In the colon, residual food, yet to be digested, will produce a bulking effect believed to be involved in the physiological activity of the colon and the production of fecal material.
Tinidazole is a versatile anti-amoebic and anti-anaerobic drug used in treatment of intestinal infection. The aim of present study was to develop and evaluate a guar gum based novel target release Tinidazole matrix tablet in animal models and healthy human volunteer using Gamma Scintigraphy technique. Anti-anaerobic and anti-protozoal activity of the developed formulation was studied in vitro against Bacteroides fragilis and Dentamoeba fragilis. Tinidazole was successful radiolabelled with (99m)Tc-pertechnetate using stannous chloride as a reducing agent and stable up to 24h in normal saline and serum. Radiolabeled formulation was evaluated in 6 Newzealand white rabbits by gamma Scintigraphy in static manner up to 24h for its retention in gastrointestinal tract (GIT). Similar set of study was conducted in 12 healthy human volunteers for similar objective Scintigraphy images of healthy human volunteer showed retention of optimized formulations in stomach up to 60min, from where it moved to duodenum further and reached ileum in around 5h. However, initiation of drug release was observed from intestine at 7h. Complete dissociation and release of drug was observed at 24h in colon due to anaerobic microbial rich environment. Results drawn from Scintigraphy images indicate that radiolabeled (99m)Tc-Tinidazole tablet transit through upper part of GI without disintegration. Hence the developed matrix tablet may have a role in treatment of intestinal infection caused by anaerobic bacteria.
Acacia gum (also known as gum arabic) is an all-natural sap that exudes from stems and branches of Acacia trees (Leguminosae), which grow in the Sahel zone of Africa. The only two botanical species allowed for food applications are Acacia senegal and Acacia seyal.
In many highly industrialized nations, colorectal cancer is the most commonly diagnosed internal malignancy when male and female rates of occurrence are combined.1–3 In Canada and the United States, in particular, it has emerged as a major cause of cancer mortality and a leading cause of significant morbidity among all types of malignancy.1,2 In 1977, over 100,000 individuals were diagnosed with large-bowel cancer in the United States alone, and about 50,000 persons died with this malignancy.1 Clearly colon cancer is one of the most serious problems facing our society. Unfortunately, even fundamental mechanisms involved in its etiology, pathogenesis, natural history, and spread of metastases are not well understood.
In the context of the conventional descriptions of the digestion of the sugars and starches in foods, the role of the microflora is regarded as a minor scavenging one, and one that moreover operates only under exceptional, usually pathological conditions[1]. The small-intestinal digestion and absorption of these food carbohydrates is assumed to be virtually complete, and the interaction of the microflora with the undigested components of the plant cell wall (dietary fibre) is assumed to be quantitatively of much greater importance.
Large bowel cancer along with breast, prostate, lung, endometrium and ovarian tumours are the leading causes of cancer mortality in the Western countries (The American Institute of Cancer Research, 1997). In addition to these cancers, other Western diseases that also contribute significantly to morbidity and sometimes mortality, include other gastrointestinal diseases (constipation, hiatus hernia, appendicitis, diverticular disease and haemorrhoids), cardiovascular diseases (coronary heart disease, stroke, essential hypertension deep vein thrombosis, pulmonary embolism, varicose veins), and metabolic diseases (obesity, diabetes, gallstones, renal stones, osteoporosis, gout). The development of these disorders appears to be associated with life style and environmental factors of which diet is a major component. (Potter, 1995; 1996).
Colon specific drug delivery system containing Aspirin as model drug was developed by varying amount of guar gum in the formulation. Granules containing different quantities of guar gum were prepared without changing the amount of Aspirin, microcrystalline cellulose and starch paste. The amount of starch paste was kept at 5 % of the combined amount of guar gum, microcrystalline cellulose and Aspirin. A decrease in rate of release of drug was observed with increase in guar gum content from formulation AG1 to AG3. The effect of presence of induced colonic microflora during in-vitro evaluation for colonic delivery of the formulations was studied and found to enhance the rate of degradation of carrier polysaccharide facilitating drug release.
Targeting drugs to the colon is one of the contemporary research areas in pharmaceutical sciences. Use of polysaccharide excipients has been the most acceptable approach. Successful delivery of drugs to colon from oral dosage forms based on polysaccharide components and / or coatings is dependent on a battery of polysaccharidases secreted by colonic microflora. Most of the reviews in the subject focus on the available polymers for colon specific drug delivery. We present a systematic account of the bacterial enzymes responsible for colonic release that shall contribute in developing novel drug delivery systems for targeting drugs to the colon. The important polysaccharidases of human colon and their mechanisms of action are dealt with in this review. The use of molecular biology tools in study of colonic microflora and genetic aspects of bacteria responsible for secretion of polysaccharidases have been compiled. The importance of use of microbial polysaccharidases in in-vitro evaluation of colon specific formulations has been discussed.
Chitosan and alginate nano-composite (NP) carriers intended for colonic delivery containing prednisolone and inulin were obtained by two processes. Spray freeze-drying using chitosan (SFDC) or alginate (SFDA) was proposed as an alternative to the traditional chitosan-tripolyphosphate platform (CTPP). NPs were fully characterised and assessed for their yield of particles; level of prednisolone and inulin release in phosphate and Krebs buffers; and sensitivity to degradation by lysozyme, bacteria and faecal slurry. NPs based on chitosan showed similar properties (size, structure, viscoelastic behaviour), but those based on SFDC showed a higher mean release of both active ingredients, with similar efficiency of encapsulation and loading capacity for prednisolone but lower for inulin. SFDC was less degraded in the presence of lysozyme and E. coli and was degraded by B. thetaiotaomicron but not by faecal slurry. The results obtained with SFDA were promising because this NP showed good encapsulation parameters for both active ingredients and biological degradability by E. coli and faecal slurry. However, it will be necessary to use alginate derivatives to reduce its solubility and improve its mechanical behaviour. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.
© 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
This study was carried out to survey the effects of laminaran and depolymerised sodium alginate (AG5), which are water soluble polysaccharides of brown algae and are not highly viscous, on the intestinal microflora and blood lipids in vitro and/or in vivo. Laminaran was fermented by human (two adults and an infant) fecal and rat cecal microflora in vitro. AG5 was fermented by these microflora besides infant fecal microflora. Laminaran was a more strongly fermented and supressed ammonia production than AG5. In vivo, the diets containing 0.4, 2 and 8% of laminaran or 0.4, 2 and 10% of AG5 were administered to male rats for one week. Eight and 10% of these polysaccharides lead to diarrhea and a decreased body weight gain. Cecal weights increased depending on the dose of the polysaccharides. Liver weights decreased depending on the dose of AG5. Cecal pH values were the lowest at 2% polysaccharides. Though 2% of laminaran increased cecal propionate and n-butyrate, 2% of AG5 decreased cecal short-chain fatty acids. AG5 decreased plasma triglycerides and cholesterol. High density lipoprotein cholesterol of plasma increased in the case of the diets containing 0.4% AG5. The ratio of cecal bifidobacteria to total bacteria was the highest, 0.4% at both polysaccharides. These results indicate that laminaran and AG5 have a profitable and different effect on intestinal microflora and levels of blood lipid depending on their concentrations.
The first recorded mention in the annals of science of the name ‘bifidus’ as applied to a cell dates to 1900, when Tissier (1900) discovered in the faeces of breast-fed infants a rod-shaped, Gram-positive, non-gas-producing, anaerobic bacterium with bifid morphology which he termed Bacillus bifidus. At the beginning of the 20th century, Orla-Jensen, in a detailed paper on bacteria that produce lactic acid, classified the Bacillus bifidus as part of the Lactobacteriaceae family, and in 1924 he tried to propose it as a separate species, explaining that the various species of bifidobacteria “doubtless constitute a separate genus, possibly forming a connecting link between lactic acid bacteria and the propionic acid bacteria”. Although studies of this bacterial group gradually declined therafter, since 1950 there has been a flourish of new research that has brought the initial listing of Lactobacillus bifidus in the seventh edition of Bergey’s Manual of Determinative Bacteriology (Breed et al., 1957) to the present 24 species noted in its latest edition (Scardovi, 1986). Since then an additional five species have been described (B. gallicum, Lauer, 1990; B. gallinarum, Watabe et al., 1983; B. ruminantium and B. merycicum, Biavati and Mattarelli, 1991; B. saeculare, Biavati et al., 1991a).
Gummivory is rare among mammals. Within primates, however, there are species from many different taxa that feed on gums and other plant exudates (Nash, 1986). Why primates appear to be predisposed to gummivory is an intriguing question. Gum would not be considered an intrinsically high quality food. It is difficult to obtain and presumed to be difficult to digest (Van Soest, 1982). It generally contains little protein, no fat and no vitamins. Gums can contain tannins, phenolic compounds, and other chemicals that have potential adverse effects for animals that ingest them (Wrangham and Waterman, 1981; Nash and Whitten, 1989). Gums do provide complex carbohydrates, and often contain significant quantities of nutritionally important minerals. But on balance, gums would not appear to be particularly good food.
The aim of this study was to isolate dextran-hydrolyzing bacteria from the human intestines and to identify their dextranolytic enzymes. For this, dextranase-producing microorganisms were screened from fecal samples by using blue dextran-containing media. Colonies producing a decolorized zone were isolated and they were grouped using RAPD-PCR. 16S rRNA gene sequencing analysis revealed the isolates were Bacteroides (B.) thetaiotaomicron, B. ovatus, B. vulgatus, B. dorei, B. xylanisolvens, B. uniformis, and Veillonella (V.) rogosae. Thin layer chromatography analysis showed that the dextranases exhibit mainly endo-type activity and produce various oligosaccharides including isomaltose and isomaltotriose. Zymogram analysis demonstrated that enzymes localized mainly in the cell membrane fraction and the molecular weight was 50-70 kDa. When cultured in a dextran-containing medium, all strains isolated in this study produced short-chain fatty acids, with butyric acid as the major compound. This is the first study to report that human intestinal B. xylanisolvens, B. dorei, and V. rogosae metabolize dextran utilizing dextranolytic enzymes. This article is protected by copyright. All rights reserved.
© 2015 Wiley Periodicals, Inc.
This study describes the application of response surface methodology in the optimization of guar gum microspheres for colon-specific delivery of metronidazole. The effect of varying the relative percent of the four factors used, that is guar gum, glutaraldehyde, swelling time, and stirring speed, has been systematically investigated for identifying their best values to optimize the drug release and encapsulation efficiency as well as to highlight possible interactions among the components. Different batches were prepared according to 24 factorial designs and randomly evaluated for drug release and drug encapsulation efficiency. Analysis of response surface plots allowed identification of the best combination of four levels to minimize drug release in upper part of gastrointestinal tract and maximize the encapsulation efficiency. The scanning electron microscopy was used to characterize the surface of these microspheres. Drug polymer interactions were assessed by differential scanning calorimetry and XRD. The good correspondence between calculated and experimental values indicated in the validity of the generated statistical model. Only a small fraction of drug was released at acidic pH; however, the release of drug was found to be higher in the presence of rat cecal contents, indicating the susceptibility of crosslinked guar gum matrix to colonic enzymes released from rat cecal contents. Metronidazole release kinetics corresponds best to zero-order model and drug release mechanism was diffusion and swelling controlled. The significance of differences was evaluated by analysis of variance (ANOVA). Differences were considered statistically significant at P < 0.05. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Enteric-coated guar gum microspheres of ornidazole aimed for colon drug delivery have been developed. The influence of core to coat ratio was investigated upon the encapsulation efficiency, swelling, weight loss and drug release behavior. The SEM was used to characterize the surface of these microspheres. Drug-polymer interactions were studied by differential scanning calorimetry and X-ray diffractometry. Enteric coating with Eudragit® S100 enabled maintenance of microspheres integrity until its expected arrival to colon. The in vitro drug release was investigated using USP dissolution rate test paddle type apparatus in different simulated mediums. Only 10 % of drug was release after 5 h while after 8 h (in PBS pH 7.5) a significant increase in percent cumulative drug release (85 %) was observed. In medium containing rat cecal content (pH 7.0) i.e. the amount of the drug released from the formulation was found to be 68 % and ˜ 78.3 % with 2 % and 4% w/v cecal matter. Drug release in presence of culture of Bacteriodes ovatus was found to be 77 %. Ornidazole release kinetics corresponds best to zero order model and drug release mechanism was diffusion and swelling controlled. The significance of differences was evaluated by analysis of variance (ANOVA). Differences were considered statistically significant at P < 0.05.
To optimize the conversion efficiency of plastic dye-sensitized solar cells fabricated by the electrophoretic deposition technique, anatase TiO2 nanoparticles of various sizes from 10 nm to 27 nm have been synthesized via a simple hydrothermal process. The obtained TiO2 nanoparticles have been characterized by X-ray diffraction and high resolution transmission electron microscopy, which confirmed that the synthesized nanoparticles are in the pure anatase phase. Rigid devices based on D149-sensitized TiO2 particles with a size of 19 nm showed the highest conversion efficiency of 7.0% among the four different devices, which was measured under illumination of AM 1.5G, 100 mWcm−2. The effect of the particle size on the photovoltaic performance of DSSCs has been systemically studied using photoelectrochemical characterizations, including intensity modulated photocurrent spectroscopy and intensity modulated photovoltage spectroscopy. The good photovoltaic performance for 19 nm TiO2 is ascribed to the good dye loading, an efficient electron transport and the high charge collection efficiency in the photoanode. Moreover, plastic DSSCs based on 19 nm TiO2 presented a conversion efficiency of 6.0% (AM 1.5G, 100 mWcm−2) under optimized conditions, showing about a 20% enhancement in the conversion efficiency as compared to that based on commercial Degussa P25 TiO2 (5.2%). These results demonstrate that optimization of the TiO2 nanoparticle size for devices fabricated using the EPD technique is an alternative method to achieve highly efficient plastic dye-sensitized solar cells.
This paper compares and contrasts the composition and properties of the microbial populations found in the anaerobic environments of the rumen and the human colon. The microbial ecosystems sustained in these organs are discussed in relation to: the structure, size and flow dynamics of the system; the nutrients available for growth; the types of microorganisms present; the metabolic pathways utilised; the interactions between microorganisms.
The intestinal microflora of humans forms a complex ecosystem that may vary with dietary intake. A randomized controlled trial with cross-over design was carried out to study the effects of two metabolic diets containing predominantly either soluble or insoluble dietary fibers on human intestinal microflora. Fecal microflora were not significantly different between the soluble and insoluble fiber group. Mean fecal mass was significantly higher with two weeks' intake of the metabolic diets. Fecal pH dropped significantly to 6.42 at week 15. Fecal aerobes were significantly lower at week 15 compared with either week 0 or 2. Fecal anaerobes and bifidobacteria counts increased significantly in week 2 but returned to their baseline levels at week 15. The logarithmic ratio of anaerobes to aerobes increased significantly from 2.08 at the baseline to 2.40 in week 15. These results showed that the intestinal microflora can be altered with intake of dietary fiber with 2 weeks of fiber intake. The drop in fecal pH at week 15 indicated that fermentation activity of the microflora may be enhanced without a detectable change in the composition of the microflora itself.
The herbal mixtures, Essiac™ and Flor-Essence™, are sold as nutritional supplements and used by patients to treat chronic conditions, particularly cancer. Evidence of anticancer activity for the herbal teas is limited to anecdotal reports recorded for some 40 years in Canada. Individual case reports suggest that the tea improves quality of life, alleviates pain, and in some cases, impacts cancer progression among cancer patients. Experimental studies with individual herbs have shown evidence of biological activity including antioxidant, antioestrogenic, immunostimulant, antitumour, and antiocholeretic actions. However, research that demonstrates these positive effects in the experimental setting has not been translated to the clinical arena. Currently, no clinical studies of Essiac™ or Flor-essence™ are published, but a clinical study is being planned at the British Columbia Cancer Agency by the University of Texas-Center for Alternative Medicine (UT-CAM) and Tzu-Chi Institute for Complementary and Alternative Medicine. Copyright © 2000 John Wiley & Sons, Ltd.
Ten Bacteroides species found in the human colon were surveyed for their ability to ferment mucins and plant polysaccharides ("dietary fiber"). A number of strains fermented mucopolysaccharides (heparin, hyaluronate, and chondroitin sulfate) and ovomucoid. Only 3 of the 188 strains tested fermented beef submaxillary mucin, and none fermented porcine gastric mucin. Many of the Bacteroides strains tested were also able to ferment a variety of plant polysaccharides, including amylose, dextran, pectin, gum tragacanth, gum guar, larch arabinogalactan, alginate, and laminarin. Some plant polysaccharides such as gum arabic, gum karaya, gum ghatti and fucoidan, were not utilized by any of the strains tested. The ability to utilize mucins and plant polysaccharides varied considerably among the Bacteroides species tested.
Quantitative and qualitative examination of the fecal flora of 20 clinically healthy Japanese-Hawaiian males was carried out by using anaerobic tube culture techniques. Cultural counts were 93% of the microscopic clump counts. Isolated colonies were selected in a randomized manner to give an unbiased sampling of the viable bacterial types. Each isolate was characterized for species identification. From a total of 1,147 isolates, 113 distinct types of organisms were observed. Statistical estimates indicate that these types account for 94% of the viable cells in the feces. The quantitative composition of the flora of this group of people, together with differential characteristics of previously unreported species, is presented for those kinds of bacteria which each represented at least 0.05% of the flora.
A microprocedure was described for determining the carbohydrate fermentation patterns of 48 anaerobic bacteria at one time in microtiter plates. The cultures were transferred into agar-filled wells of microtiter plates with a replicator inside an anaerobic glove box. Fermentation was measured both with a colorimetric indicator and with a small pH electrode. The method was approximately 97% accurate. It would be most useful for laboratories that need to identify large numbers of anaerobes at one time.
A replicator is described for transferring 48 bacterial cultures into separate wells of microtiter plates. The device was designed for determination of carbohydrate fermentation patterns of anaerobic bacteria but should be useful for other applications. A simple device for filling microtiter wells with media is also described.
In the reported experiments, high-performance liquid chromatography has been applied to the analysis of the sugars produced during the enzymatic hydrolysis of cellulosic wastes. The three primary products - xylose, glucose and cellobiose - can be separated in 4 min, and microgram quantities can be determined with good precision and accuracy. Filtration is the only pretreatment required. Minor sugars which are commonly present in the hydrolysates can also be separated for analysis or identification by modifications in the eluting solvent. Use of the method is illustrated with samples from a study of the effect of temperature (45 - 60 degree C) on the hydrolysis of ball-milled newspaper by an enzyme preparation from Trichoderma viride. Temperature had little effect on the extent of saccharification, but markedly affected the rate of saccharification and the relative concentration of glucose and cellobiose in the hydrolysates.
Concentrations of water-soluble high- and low-molecular-weight carbohydrates were determined in the intestinal contents of four human subjects who had died accidentally. In all four subjects, concentrations of high-molecular-weight carbohydrate were lower throughout the colon than in the ileum. In some subjects, similar but less dramatic differences were also found with low-molecular-weight carbohydrate. Components of both high- and low-molecular-weight peaks included neutral sugars such as rhamnose, galactose, mannose, xylose, and arabinose, which are found in many plant polysaccharides. Components characteristic of mucins (fucose, hexosamines, and sialic acids) were also detected. These results indicate that dietary fiber and mucin are degraded in the human colon.
Laminarin, a beta(1 leads to 3)-glucan similar to those found in plant cell walls, is fermented by some species of anaerobic bacteria from the human colon. Laminarinase (EC 3.2.1.6) and beta-glucosidase (EC 3.2.1.21) activities were determined in strains representing Bacteroides thetaiotaomicron, Bacteroides distasonis, and an unnamed deoxyribonucleic acid homology group of Bacteroides fragilis. In all three species, laminarinase activity was inducible by laminarin and was predominantly cell bound. The products of laminarinase activity varied with each species. In the case of B. thetaiotaomicron, the major product of laminarin hydrolysis was glucose (70 to 90%), and there were small amounts of laminaribiose (G2) and oligomers of glucose as high as G4. In the case of group '0061-1,' glucose (40 to 50%) and oligomers of glucose as high as G6 were found. The laminarinase of B. distasonis differed from the laminarinases of the other two species in that it mainly produced oligomers of glucose (G2-G5). beta-Glucosidase activity was also found in all three species. beta-Glucosidase was induced by glucose-containing disaccharides as well as by laminarin. The beta-glucosidases of the three Bacteroides species differed with respect to level of activity, induction pattern, and sensitivity to inhibition by D-glucono-1,5-lactone.
Human intestinal goblet cell mucin
- Jabal