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Characterization of Solibacillus silvestris strain AM1 that produces amyloid bioemulsifier
Abstract
Solibacillus silvestris AM1 was the first strain from the genus to be reported for the production of a functional amyloid and its potential use as a surface active agent, a thermostable glycoprotein amyloid bioemulsifier BE-AM1 capable of influencing environment and biofilm formation. Phylogenetic analysis based on 16S rRNA gene, molecular characterization studies on the basis of DNA-DNA hybridization and chemotaxonomic fatty acid methyl ester (FAME) analysis showed that S. silvestris AM1 as a strain matches with the type strain S. silvestris HR3-23. But strain AM1 differs from the type strain HR3-23 in carbon substrate utilization studies along with amyloid bioemulsifier production ability with potential industrial and environmental applications. S. silvestris AM1 exhibited bioemulsifier production at wide range of factors like pH and NaCl concentrations, while temperature influenced the bioemulsifier production indirectly (since it affected the growth). Bioemulsifier production was observed even at oligotrophic conditions (0.5mg/ml) seen usually in its native environmant. In this study, we have characterized the amyloid producing S. silvestris AM1 taxonomically and also analyzed 16S rDNA of 103 sequences of Solibacillus sp. available, which indicated the possibility of new species in this genus and can be studied for industrially and environmentally important biomolecules.
... Previous studies identified artificial waterholes as healthriskier compared with natural ones since the latter possess natural systems that might counter the spread of pathogens ( Foster 2019 ). These natural systems consist of fungi and plants whose interactions prevent the development and survival of pathogens in the environment through several mechanisms ( Gupta et al. 2012 ;Markande et al. 2018 ). ...
In dry climates, livestock farming contributes to waterhole creation and maintenance, thereby contributing to biodiversity conservation. However, these lentic water bodies also represent a critical environmental connection between microorganisms and their vertebrate hosts since the water can facilitate pathogen persistence and transmission. Therefore, interventions for tuberculosis (TB) risk mitigation at the wildlife-livestock interface often focus on segregating host species at water points. We hypothesized that water-hole characteristics modulate their use by vertebrates and subsequent pathogen exposure risk. We visited 298 waterholes on 80 TB-positive and 40 TB-negative cattle farms in Spain to assess differences in water-hole characteristics and identify possible management implications. There was an average of 2.7 water-holes per farm. This represents 0.02 waterholes per km 2 of farmland and 3.5 m 2 of lentic waterbodies per km 2 of farmland. Among the studied waterholes, 95% were man-made. Waterholes on TB-positive farms were 42% closer to covering vegetation than waterholes located on TB-negative ones. Farms with man-made waterholes showed a higher risk of TB than those with natural ones. The density of waterholes per surface unit was negatively associated with the farm TB risk. Waterholes placed on TB-positive farms were more intensively trampled by livestock. The best model explained farm positivity to TB as a function of the distance from the waterholes to the nearest cover vegetation, the aquatic vegetation richness found in the waterhole, the intensity of livestock use (trampling), the surrounding waterhole density, and the interaction between waterhole perimeter and the total number of signs of potential wildlife TB hosts per waterhole. Identifying the key waterhole features related to infection risk might allow designing One Health −inspired biosecurity measures such as increasing the number of waterholes, placing new water-holes farther away from cover, or fencing-out cattle from wildlife-rich waterholes to balance biodiversity conservation and animal health needs in extensive grazing systems.
... Biosurfactants are amphiphilic molecules with various structural configurations and multifunctional capabilities used in various industries, such as the cosmetic, food processing, pharmaceutical, textile, and paint industries (Gaur et al. 2022). Biosurfactants are amphipathic biomolecules that are usually produced by a diverse range of microorganisms as a mixture of different biomolecules that are differentiated into relatively smaller ones (around 1-2 kDa) biosurfactants and polymeric bioemulsifiers (having larger size) (Markande et al. 2018b). Well-known biosurfactants have been enlisted in Table 1. ...
Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can `be replaced in biotechnological applications depending on the compatibility of the processes.
... Finally, the Indian Cove layer community was explained by Pseudomonas, Acinetobacter, Rheinheimera, and Phenylobacterium, and Trichococcus, Sphingorhabdus, Solibacillus, and Herminiimonas were unique taxa. Many of these taxa are common soil bacteria [77][78][79][80][81], while Rheinheimera is found in mangrove sediments [82] and Herminiimonas in deep glacial ice [83] and mineral water [84]. These taxa could be indicative of the terrestrial and plant-covered land from which these rocks were formed. ...
The deep terrestrial subsurface, hundreds of meters to kilometers below the surface, is characterized by oligotrophic conditions, dark and often anoxic settings, with fluctuating pH, salinity, and water availability. Despite this, microbial populations are detected and active, contributing to biogeochemical cycles over geological time. Because it is extremely difficult to access the deep biosphere, little is known about the identity and metabolisms of these communities, although they likely possess unknown pathways and might interfere with deep waste deposits. Therefore, we analyzed rock and groundwater microbial communities from deep, isolated brine aquifers in two regions dating back to the Ordovician and Devonian, using amplicon and whole genome sequencing. We observed significant differences in diversity and community structure between both regions, suggesting an impact of site age and composition. The deep hypersaline groundwater did not contain typical halophilic bacteria, and genomes suggested pathways involved in protein and hydrocarbon degradation, and carbon fixation. We identified mainly one strategy to cope with osmotic stress: compatible solute uptake and biosynthesis. Finally, we detected many bacteriophage families, potentially indicating that bacteria are infected. However, we also found auxiliary metabolic genes in the viral genomes, probably conferring an advantage to the infected hosts.
... The microbial synthesis and excretion of biomolecules is induced by several physical and nutritional factors (Markande et al. 2018). In this regard, the proper selection of substrate type directly affects the microbial metabolism for the biosynthesis of surface-active compounds such as bioemulsifiers (Bertrand et al. 2018). ...
Microbial bioemulsifiers are molecules of amphiphilic nature and high molecular weight that are efficient in emulsifying two immiscible phases such as water and oil. These molecules are less effective in reducing surface tension and are synthesized by bacteria, yeast and filamentous fungi. Unlike synthetic emulsifiers, microbial bioemulsifiers have unique advantages such as biocompatibility, non-toxicity, biodegradability, efficiency at low concentrations and high selectivity under different conditions of pH, temperature and salinity. The adoption of microbial bioemulsifiers as alternatives to their synthetic counterparts has been growing in ongoing research. This article analyzes the production of microbial-based emulsifiers, the raw materials and fermentation processes used, as well as the scale-up and commercial applications of some of these biomolecules. The current trend of incorporating natural compounds into industrial formulations indicates that the search for new bioemulsifiers will continue to increase, with emphasis on performance improvement and economically viable processes.
... It is indicated that the host genetic factors have an influence on the structure and abundance of intestinal microbiota at the genus level. In addition, Lactobacillus are reported as probiotics in virtue of their anti-inflammatory ability (25), presence of three species of Solibacillus have been reported, of which Solibacillus silvestris can produce antineoplastic biomolecule (26). On the other hand, Stenotrophomonas species are multi-resistant bacteria with ability to cause opportunistic infections (27), and Pseudomonas has been reported as a known pathogen of mastitis microbiota in ruminants (28). ...
The gut microbiota plays vital roles in metabolizing nutrient, maintaining the intestinal epithelial barrier but also in modulating immunity. Host genetics and the pig breed are implicated in shaping gut microbiota. Tibetan pig is a unique native Chinese breed and has evolved to manifest a strong disease resistance. However, the immunity and microbiota of growing Tibetan (TP) pigs were still rarely understood. The jejunal immunity phenotype and microbial composition of TP and Duroc × (Landrace × Yorkshire) (DLY) pigs were explored through immunohistochemistry and 16S rRNA sequencing. Higher scores of clusters of differentiation 4 (CD4+) and Toll-like receptor 9 (TLR9) were observed in TP pigs than those of DLY pigs ( p < 0.05), as were Interleukin 10 (IL-10) and zonular occludens 1 (ZO-1) ( p < 0.01). Similar levels of bacterial richness and diversity were found in the jejunal microbiota of the TP and DLY pigs. However, the TP pigs showed a significantly different microbiome compared to DLY pigs at the genus level (ANOSIM; p < 0.05). Pseudomonas, Stenotrophomonas, Phenylobacterium , and Sandaracinobacter were enriched in DLY pigs ( p < 0.05), while the Lactobacillus and Solibacillus had higher abundances in TP pigs than DLY pigs ( p < 0.05). Tibetan pigs have “healthier” intestinal microbial communities than DLY pigs. Close relationships were found between jejunal immune performance and the differential bacteria, Lactobacillus can enhance porcine jejunal immunity, while Stenotrophomonas will have a negative impact on porcine gut immunity.
... Aerobic plate counts (APCs) were highest on the raisins, i.e., approximately 5.0 log CFU/g, which also demonstrated a greater species diversity as compared to the dried apples. The most abundant bacteria recovered from the raisins were Bacillus spp., but determination of the exact species could not be obtained with confidence by 16S rRNA gene comparison, because of the high degree of similarity among species of this genus (Mclauchlin and Rees, 2009 These species have all been isolated from soil and thus may have originated from the farm environment (Jung et al., 2003;Markande et al., 2018;Reva et al., 2002). However, some of these species could have also been introduced at the processing plant given the ubiquitous and hardy nature of Bacillus spores (Ryu and Beuchat, 2005;Soni et al., 2016). ...
The survival of Listeria monocytogenes was assessed during long-term storage on three dried fruits: dried apples, raisins and dried strawberries. Using sand as a carrier, the dried fruits were dry-inoculated with a four-strain cocktail of L. monocytogenes to achieve numbers of 4.0 to 4.6 log CFU/g. The inoculated foods were stored at 4°C, 25–81% relative humidity (RH) and 23°C, 30–35% RH for 336 days. Colonies of L. monocytogenes could not be recovered from the dried apples after inoculation, i.e., day 0. Concentrations of L. monocytogenes decreased rapidly on the raisins and dried strawberries during storage at 23°C, with enhanced survival observed at 4°C. Linear rates of decline for populations of L. monocytogenes during storage at 4°C on the raisins and dried strawberries were 0.1 and 0.2 log CFU/g/month, respectively. The relative distribution of the four L. monocytogenes strains making up the cocktail was determined by multiplex PCR at the beginning of storage and after 336 days on the dried fruits. At day 0, L. monocytogenes populations were predominantly composed of the serotype 1/2a and 3a strains on both the raisins and dried strawberries. After long-term storage at 4°C, a relative decrease in serotype 1/2a was observed on both fruits, coupled with relative increases in the serotype 3a strain during storage on both fruits, in addition to the serotype 1/2b strain on the raisins. These results demonstrate that L. monocytogenes is rapidly inactivated during storage on raisins and dried strawberries at 23°C, but capable of long-term survival at 4°C. Improved knowledge on the survival of L. monocytogenes on these commodities is important for predictive modeling and can be used to better inform microbial health risk assessments.
There is a growing interest in the development and use of natural emulsifiers, which provide biodegradability as well as non-toxicity along with giving better performance compared to existing emulsifying agents used in the food industry. A large variety of sources of starting material, i.e., the microorganisms, are available to be used, hence giving a diverse range of applications. The focus of this review paper is on the production of bioemulsifiers, which are said to be “green surfactants”, from fungi, bacteria and yeasts; furthermore, an overview pertaining to the knowledge gained over the years in terms of characterization techniques is reported. The methods used for the characterization and isolation such as TLC, GC-MS, HPLC, NMR have also been studied. The end-application products such as cookies, muffins, and doughs along with the methods used for the incorporation of bioemulsifiers, microorganisms from which they are derived, properties imparted to the product with the use of a particular bioemulsifier and comparison with the existing food grade emulsifiers has been discussed in detail. The future prospects indicate that newer bioemulsifiers with anti-microbial, anti-oxidant and stabilization properties will prove to have a larger impact, and emphasis will be on improving the performance at an economically viable methodology. View Full-Text
Microbial surfactants are a large number of amphipathic biomolecules with a myriad of biomolecule constituents from various microbial sources that have been studied for their surface tension reduction activities. With unique properties, their applications have been increased in different areas including environment, medicine, healthcare, agriculture and industries. The present review aims to study the biochemistry and biosynthesis of biosurfactants exhibiting varying biomolecular structures which are produced by different microbial sources. It also provides details on roles played by biosurfactants in nature as well as their potential applications in various sectors. Basic biomolecule content of all the biosurfactants studied showed presence of carbohydrates, aminoacids, lipids and fattyacids. The data presented here would help in designing, synthesis and application of tailor-made novel biosurfactants. This would pave a way for perspectives of research on biosurfactants to overcome the existing bottlenecks in this field.
We present the latest version of the Molecular Evolutionary Genetics Analysis (MEGA) software, which contains many sophisticated
methods and tools for phylogenomics and phylomedicine. In this major upgrade, MEGA has been optimized for use on 64-bit computing
systems for analyzing bigger datasets. Researchers can now explore and analyze tens of thousands of sequences in MEGA. The
new version also provides an advanced wizard for building timetrees and includes a new functionality to automatically predict
gene duplication events in gene family trees. The 64-bit MEGA is made available in two interfaces: graphical and command line.
The graphical user interface (GUI) is a native Microsoft Windows application that can also be used on Mac OSX. The command
line MEGA is available as native applications for Windows, Linux, and Mac OSX. They are intended for use in high-throughput
and scripted analysis. Both versions are available from www.megasoftware.net free of charge.
Isolates were obtained from intertidal zone site samples from all five western and one eastern coastal states of India and were screened. These ecophysiological groups of aerobic, mesophilic, heterotrophic, sporulating, and bioemulsifier-producing bacteria were from Planococcaceae and Bacillaceae. This is the first report of bioemulsifier production by Sporosarcina spp., Lysinibacillus spp., B. thuringiensis, and B. flexus. In this group, Solibacillus silvestris AM1 was found to produce the highest emulsification activity (62.5 %EI) and the sample that yielded it was used to isolate the ecophysiological group of non-bioemulsifier-producing, hydrocarbon-degrading bacteria (belonging to Chromatiales and Bacillales). These yielded hitherto unreported degrader, Rheinheimera sp. CO6 which was selected for the interaction studies (in a microcosm) with bioemulsifier-producing S. silvestris AM1. The gas chromatographic study of these microcosm experiments revealed increased degradation of benzene, toluene, and xylene (BTX) and the growth of Rheinheimera sp. CO6 in the presence of bioemulsifier produced by S. silvestris AM1. Enhancement of the growth of S. silvestris AM1 in the presence of Rheinheimera sp. CO6 was observed possibly due to reduced toxicity of BTX suggesting mutualistic association between the two. This study elucidates the presence and interaction between enhancers and degraders in a hydrocarbon-contaminated intertidal zone and contributes to the knowledge during application of the two in remediation processes.
The recently-developed statistical method known as the "bootstrap" can be used to place confidence intervals on phylogenies. It involves resampling points from one's own data, with replacement, to create a series of bootstrap samples of the same size as the original data. Each of these is analyzed, and the variation among the resulting estimates taken to indicate the size of the error involved in making estimates from the original data. In the case of phylogenies, it is argued that the proper method of resampling is to keep all of the original species while sampling characters with replacement, under the assumption that the characters have been independently drawn by the systematist and have evolved independently. Majority-rule consensus trees can be used to construct a phylogeny showing all of the inferred monophyletic groups that occurred in a majority of the bootstrap samples. If a group shows up 95% of the time or more, the evidence for it is taken to be statistically significant. Existing computer programs can be used to analyze different bootstrap samples by using weights on the characters, the weight of a character being how many times it was drawn in bootstrap sampling. When all characters are perfectly compatible, as envisioned by Hennig, bootstrap sampling becomes unnecessary; the bootstrap method would show significant evidence for a group if it is defined by three or more characters.
A novel estuarine bacterial strain, Solibacillus silvestris AM1 produces extracellular, thermostable and fibrous, glycoprotein bioemulsifier AM1 (BE-AM1). The amyloid nature of bioemulsifier (BE-AM1) was confirmed by biophysical techniques (Congored based polarization microscopy; ThioflavinS based fluorescent microscopy, fibrous arrangement in transmission electron microscopy and secondary structure measurement by FTIR and CD spectrum analysis). Cell-bound BE-AM1 production by S. silvestris AM1 during the mid logarithmic phase of growth coincided with decrease in cell surface hydrophobicity, increase in cell autoaggregation and biofilm formation. It was observed that the total interfacial interaction energy ( ) for the surface of bioemulsifier producing S. silvestris AM1 and different derivatized surfaces of polystyrene (silanized and sulfonated) was found to support biofilm formation. This study has revealed that the BE-AM1, a bacterial bioemulsifier is a functional amyloid and has a role in biofilm formation and cell surface modulation in S. silvestris AM1.
A new method called the neighbor-joining method is proposed for reconstructing phylogenetic trees from evolutionary distance data. The principle of this method is to find pairs of operational taxonomic units (OTUs [= neighbors]) that minimize the total branch length at each stage of clustering of OTUs starting with a starlike tree. The branch lengths as well as the topology of a parsimonious tree can quickly be obtained by using this method. Using computer simulation, we studied the efficiency of this method in obtaining the correct unrooted tree in comparison with that of five other tree-making methods: the unweighted pair group method of analysis, Farris's method, Sattath and Tversky's method, Li's method, and Tateno et al.'s modified Farris method. The new, neighbor-joining method and Sattath and Tversky's method are shown to be generally better than the other methods.
A format for the description of single novel species is proposed, which should facilitate the reviewing process by assisting the provision of data in a standardized form. The abstract must be short and concise, highlighting phylogenetic position, morphology and chemotaxonomy for genus affiliation, the genotypic and phenotypic basis for species differentiation, and the name and deposition numbers from two public culture collections in different countries for the type strain: A Gram-negative, rod-shaped, non-spore-forming bacterium (Iso 196 T ) was isolated from chicken faeces. On the basis of 16S rRNA gene sequence similarity, strain Iso 196 T was shown to belong to the α-2 subclass of the Proteobacteria related to Ochrobactrum tritici (95.6 %), Ochrobactrum grignonense (95.0 %) and Ochrobactrum anthropi (94.6 %), and the phylogenetic distance from any validly described species within the genus Brucella was less than 95 %. Chemotaxonomic data (major ubiquinone - Q-10; major polyamines - spermidine and putrescine; major polar lipids -phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine; major fatty acids -C 18:1 (1)7c and C 19:0 cyclo (1)8c) supported the affiliation of strain Iso 196 T to the genus Ochrobactrum. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain Iso 196 T from the four validly published Ochrobactrum species. Iso 196 T therefore represents a new species, for which the name Ochrobactrum gallinifaecis sp. nov. is proposed, with the type strain Iso 196 T ( = DSM 15295 T =CIP 107753 T ).