[Show abstract][Hide abstract] ABSTRACT: Objective: A relatively new local type of eggplant, Solanum melongena L. ‘Kadife’ is widely
consumed in Turkey because of its economic availability and good nutritional qualities.
However, the high polyphenol content of eggplant renders it susceptible to unattractive
oxidative browning catalyzed by polyphenol oxides (PPOs). Therefore, the main aim of this
study was to characterize PPO in this eggplant cultivar at three stages of its development.
Methods: In this study, we determined substrate specificity, optimum pH and temperature, and
optimum substrate concentration of the partial purified eggplant fruits PPO during ripening.
Results: L-DOPA was proved to be the preferred PPO substrate in all three stages of ripening.
Optimum activity was observed at pH 7.0 for PPO in extracts of ripening and overly-ripe
eggplant, while activity in extracts of immature eggplant exhibited a broad pH optimum
between, pH 5.0 and 7.0. In general, at all ripening stages, PPO was most active at 30°C and
was most sensitive to inhibition by sodium metabisulphite and ascorbic acid. The metal ions
(Hg2+, Mn2+, Fe3+ and Co2+) mostly inhibited PPO activities.
Conclusion: These data regarding the properties of PPO should enhance understanding of the
browning reaction in eggplant and lead to the development of techniques for controlling this
Turkish Journal of Biochemistry 08/2014; 40(1):44-50. DOI:10.5505/tjb.2015.27146
[Show abstract][Hide abstract] ABSTRACT: The D-glucose/D-xylose isomerase was purified from a thermophilic bacterium, Geobacillus thermodenitrificans TH2, by precipitating with heat shock and using Q-Sepharose ion exchange column chromatography, and then characterized. The purified enzyme had a single band having molecular weight of 49 kDa on SDS-PAGE. In the presence of D-glucose as a substrate, the optimum temperature and pH of the enzyme were found to be 80°C and 7.5, respectively. The purified xylose isomerase of G. thermodenitrificans TH2 was extremely stable at pH 7.5 after 96 h incubation at 4°C and 50°C. When the thermal stability profile was analyzed, it was determined that the purified enzyme was extremely stable during incubation periods of 4 months and 4 days at 4°C and 50°C, respectively. The K
m and V
max values of the purified xylose isomerase from G. thermodenitrificans TH2 were calculated as 32 mM and 4.68 μmol/min per mg of protein, respectively. Additionally, it was detected that some metal ions affected the enzyme activity at different ratios. The enzyme was active and stable at high temperatures and nearly neutral pHs which are desirable for the usage in the food and ethanol industry.
[Show abstract][Hide abstract] ABSTRACT: An esterase from a thermophilic bacterium, Geobacillus sp. DF20, was partially purified. Final purification factor was found to be 64.5-fold using Q-Sepharose ion exchange column chromatography. Native polyacrylamide gel electrophoresis indicated the presence of a single active esterase. The substrate specificity of this esterase was high for p-nitrophenyl butyrate (pNPB) substrate. The optimum pH and temperature for the enzyme activity were 7.0 and 50 degrees C, respectively. The pH and heat stability profiles show that this enzyme is more stable under neutral conditions at 50 degrees C. K-m and V-max values for this esterase acting on pNPB were 0.12 mM and 54.6 U/mg protein, respectively. Presence of 10% (v/v) acetonitrile in the reaction medium indicated that purified enzyme was strongly inhibited. It was also detected that some metal ions affected enzyme activity at different rates. As a result, it was observed that esterase from Geobacillus sp. DF20 has extreme temperature and pH stabilities. Therefore, the stability and K-m value of the enzyme make this study interesting when compared with the literature.
[Show abstract][Hide abstract] ABSTRACT: Objective: To purify and characterize an esterase from a thermophilic bacterium, Geobacillus sp. TF17. Methods: The crude esterase was purified by using acetone precipitation and ion exchange choromatography methods and characterized. Results: The optimum temperature and pH of the enzyme were found to be 50 degrees C and 7.5, respectively. The purified enzyme was extremely stable in the range of pH 4.0-9.0 after 72 hour incubation at 4 degrees C. The thermal stability profile shows that this enzyme is stable in the range of 30-50 degrees C after 72 h incubation. The K-m and V-max values for this esterase in the presence of p-nitrophenyl butyrate (pNPB) as substrate were found as 0.056 mM and 19.38 U/mg protein, respectively. The enzyme activity was inhibited more than about 60% in the presence of some organic solvents such as isopropanol and acetonitrile. Additionally, it was detected that some metal ions affect the enzyme activity at different ratio. Conclusion: An esterase was purified and characterized from Geobacillus sp. TF17. The pH and thermal stability of purified enzyme are quite high. The data obtained from this study show that the purified esterase has advantages for industrial or biotechnological applications in terms of especially its high thermal-and pH-stability.
Türk Biyokimya Dergisi / Turkish Journal of Biochemistry 09/2013; 38(3). DOI:10.5505/tjb.2013.36035 · 0.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An esterase from Lycoperdon pyriforme was characterized. The enzyme had a maximum activity at pH 8.0 and 40C with p-nitrophenyl acetate as a substrate. Km and Vmax values were calculated as 2.13 mM and 0.65 U/mg protein, respectively. The enzyme activity was conserved more than 90% over a broad range of pH (3.0–9.0) at 4C after 24 h of incubation. The activity increased 37 ± 3.6% after 120 min of incubation at 40C. Li+, Mg2+ and Ca2+ activated the enzyme 12 ± 1.8, 16 ± 2.5 and 15 ± 2.5%, respectively. The esterase was inhibited in different ratios by some detergents such as Triton X-114, Triton X-100, Tween 20 (Sigma Chemical Co., St. Louis, MO) and sodium dodecylsulfate. It retained most of its activity in the presence of methanol and dimethylsulphoxide at the final concentration of 10% (v/v). pH and moderate thermal stability of L. pyriforme esterase and its activity in some organic solvents could make it useful for some industrial purposes such as detergent and paper industry. PRACTICAL APPLICATIONSEsterases play a major role in the degradation of natural materials and industrial pollutants, viz., cereal wastes, plastics and other toxic chemicals. They are also useful in the synthesis of optically pure compounds, perfumes and antioxidants. Because of these biocatalytic applications, it may be interesting to study novel esterases from different organisms. Therefore, it is important to study esterase activity of Lycoperdon pyriforme. In this way, a new esterase having potential applications can be found.
[Show abstract][Hide abstract] ABSTRACT: Polyphenol oxidase (PPO) was purified from Lactarius piperatus (L.) Pers. by using Sepharose 4B‐L‐tyrosine‐p‐amino benzoic acid affinity column. Optimum pH and temperature of purified PPOs of L. piperatus were found to be 7.0 and 20C, respectively, by using catechol as a substrate. The enzyme retained 100% of its original activity at 4C and its optimum pH value for 24 and 72 h. L. piperatus PPO was also quite stable at 20C after 4 h incubation. The K m and V max values were calculated as 1 mM and 25 U/mg protein, respectively. Ascorbic acid was found to be the most potent inhibitor for the enzyme. The mushroom PPO was an effective biocatalyst in the selected organic solvents such as dichloromethane, heptane and toluene when using catechin as a substrate. All data support that L. piperatus has a highly active PPO possessing similar biochemical and kinetic characteristics to some plant PPO enzymes. PRACTICAL APPLICATIONSPolyphenol oxidases (PPOs) are a group of copper‐containing enzymes that are widely distributed from bacteria to mammals. Some different mushroom PPOs are subjected to further characterization studies in terms of their biochemical characteristics and their potentials in biotechnological applications. So, purification and characterization studies for PPOs from new sources are very important to explain their biochemical properties and behavior. Thus, one more enzyme may also find applications in food or drug industries.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate nitric oxide (NOx) concentration in infected and non-infected mammary quarters of dairy heifers before and after calving. The relationship between bacterial species and NOx concentrations, as well as correlation between NOx concentrations and postpartum somatic cell count (SCC), was assessed. Coagulase-negative staphylococci, Staphylococcus aureus and Escherichia coli were the bacteria commonly isolated during the pre- and postpartum period. Infected quarters had greater NOx concentrations than non-infected quarters before (30.81 v. 22.83 μM/ml, P < 0.05) and after (9.56 v. 5.77 μM/ml, P < 0.0001) calving. It was determined that the interaction between sampling period and infectious status had no effect on NOx concentration (P < 0.16). Infected quarters had greater SCC (log10) than healthy quarters (4.95 v. 4.39; P < 0.0001). NOx concentrations, however, did not correlate with SCC (r = 0.02). In summary, changes in NOx concentration were mainly dependent on the infectious status of the quarters with variations among the bacterial species (P < 0.05).
[Show abstract][Hide abstract] ABSTRACT: The present study aimed to investigate time-dependent changes in leptin concentrations in brain tissue following experimental traumatic brain injury and to examine the relationship with cytokines.
After circular craniectomy, 33 male Wistar-albino rats were positioned on a stereotaxic frame and subjected to cortical contusion injury and then divided into 3 groups based on the depth of deformation as: 0 mm (sham controls, n=3), 1.5 mm (moderate injury, n=15) and 2.7 mm (severe injury, n=15). Animals were sacrificed on the 1st, 3rd and 5th days post-injury.
One day after moderate injury, interleukin-1 beta (IL-1ß), IL-6, tumor necrosis factor-alpha (TNF-?), and leptin levels were found to be markedly increased in the brain tissue. On the 3rd and 5th days, the levels returned to the shamcontrol levels. Following severe injury, IL-1ß, IL-6 and TNF-? levels increased in correlation after the 1st day and reached the sham-control levels on the same days. However, leptin tissue levels decreased on the 1st and 3rd days and normalized to the sham-control levels on the 5th day.
Our results showed that the release of leptin is decreased in the early stage of severe injury. Thus, leptin replacement may play an important role in therapy in cases with severe traumatic brain injury.
Ulusal travma ve acil cerrahi dergisi = Turkish journal of trauma & emergency surgery: TJTES 07/2011; 17(4):298-302. DOI:10.5505/tjtes.2011.69077 · 0.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to compare the clinical and endocrinological effects of four different treatments for the induction of abortion in bitches. For this purpose, 28 pregnant bitches between days 25 and 35 of gestation, were randomly assigned to four groups. In group I (n = 7), only aglepristone (AGL, 10mg/kg bw, two injections 24 h apart, s.c.) was administered. In group II (n = 7), AGL (as in group I), cabergolin (CAB, 5 μg/kg, daily p.o., until completion of abortion) and misoprostol (MIS, 200 μg for bitches with ≤ 20 kg bw, 400 μg for bitches with > 20 kg bw, daily intravaginally, until completion of abortion) were administered. In group III (n = 7), AGL (as in group I) and MIS (as in group II) were administered. In group IV (n = 7) AGL, (as in group I) and cloprostenol (CLO, 1μg/kg bw, s.c., two injections 24 h apart with the AGL injections) were combined. In all groups, bitches were examined daily, clinically and ultrasonographically to monitor resorptions/abortions. To measure serum progesterone (P4) and total estrogen (TE) concentrations, blood samples were collected in all groups immediately after the first AGL administration and every other day until completion of abortion. No statistical differences were found between groups concerning the duration until completion of abortion following treatment (n.s.); however, in Group III, 6 d after the start of treatment all pregnancies were terminated whereas in Group I, II and IV, only 57.1% (4/7), 85.7 % (6/7) and 42.8 % (3/7) of pregnancies were terminated. In the latter groups, all pregnancies were terminated between days 8 and 10 after the start of treatment. In Group IV, P4 concentrations on days two and one before the beginning of abortion and the day the abortion started was significantly lower than in the other groups (P < 0.01). No statistical differences were found between groups for TE concentrations (P > 0.05). In Groups I, II and III, no severe side effects occurred. Severe vomiting after each treatment and until the end of abortion was observed in Group IV only. In conclusion, only when a combination of AGL and MIS was used abortion was completed within 6 d in all bitches whereas the additional use of CAB did not improve the treatment.
[Show abstract][Hide abstract] ABSTRACT: Pneumorrhachis is defined as the presence of air in the epidural space or subarachnoid space. The air may migrate along fascial planes from the posterior mediastinum, through the neural foramina, and into the epidural space. Pneumorrhachis is rare, and even more so in the paediatric population. Pneumorrhachis in itself usually is asymptomatic, does not tend to migrate and reabsorbs spontaneously. The combination of pneumomediastinum with epidural pneumorrhachis without thoracic trauma has rarely been reported in the literature. The present case report describes the presence of pneumomediastinum, subcutaneous emphysema, and pneumorrhachis in a child asthmatic patient who had a history of fever, violent cough.
[Show abstract][Hide abstract] ABSTRACT: The fatty acid and amino acid compositions of 11 mushroom species commonly consumed were collected from the East Black Sea region of Turkey and analyzed. All species were characterized by a high content of linoleic acid (C18:2n-6) and glutamic acid. The highest content of linoleic acid (78.0%) and glutamic acid (29.4 μg/mg dry weight [d.w.]) was found in Agaricus arvensis and the lowest in Cantharellus tubaeformis, 19.8% and 10.9 μg/mg d.w., respectively. The average content of amino acids for all species was 148 μg/mg d.w. Overall, these results demonstrate that the 11 different kinds of wild edible mushrooms gathered from the region represent substantial sources of fatty acids and amino acids that are essential in the diet of humans. Quality of the mushroom protein compares favorably with the FAO/WHO Standard. The present study demonstrates that macrofungi from the East Black Sea region (Turkey) are a good source of many nutrients essential to human well-being.
International Journal of Food Sciences and Nutrition 12/2010; 62(4):328-35. DOI:10.3109/09637486.2010.533160 · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Some homo- and heteronuclear Cu(II) and Ni(II) complexes of new oxime-type ligands were tested against several pathogenic microorganisms to assess their antimicrobial potentials. The antimicrobial activities of complexes were evaluated in terms of minimum inhibitory concentration (MIC; μg/μL) and it was observed that the complexes possess moderate antimicrobial properties. The binding of the complexes with DNA were also investigated by using UV-Vis spectroscopy. It was seen that three of the complexes could bind to DNA through an intercalative mode while the other complexes could have other mechanisms. Furthermore, the antioxidant efficiencies of the metal complexes were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavening activities. Due to the observed IC(50) values, they are potential drugs to eliminate the radicals.
European Journal of Medicinal Chemistry 11/2010; 45(11):5169-75. DOI:10.1016/j.ejmech.2010.08.031 · 3.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A crude extract was prepared from the fruiting body of Lepista flaccida, an edible mushroom and endoglucanase activity of the extract was increased 14-fold with ammonium sulphate precipitation. Maximum enzyme activity was seen at pH 4.0 and 50°C when carboxymethylcellulose was used as a substrate. K0.5 and Vmax values of the partially purified endoglucanase were 7.7mg/ml and 25±0.9U/mg protein, respectively. The enzyme was quite stable over a broad range of pH (2.0–9.0) at 4°C. When it was incubated at temperatures between 20°C and 60°C for 12h, it conserved much of its original activity (over 40%). The activity of the enzyme increased by 234±3.6% in the presence of 1mM Mn2+. The endoglucanase was inhibited by EDTA, PMSF, β-ME and DDT. In conclusion, pH and thermal stability of the L. flaccida endoglucanase could make it useful for industrial purposes.
[Show abstract][Hide abstract] ABSTRACT: The objectives of this experiment were to determine interrelationships among mastitis indicators and evaluate the subclinical mastitis detection ability of infrared thermography (IRT) in comparison with the California Mastitis Test (CMT). Somatic cell count (SCC), CMT, and udder skin surface temperature (USST) data were compiled from 62 Brown Swiss dairy cows (days in milk=117+/-51, milk yield=14.7+/-5.2 kg; mean +/- SD). The CORR, REG, and NLIN procedures of Statistical Analysis System (SAS Institute Inc., Cary, NC) were employed to attain interrelationships among mastitis indicators. The diagnostic merit of IRT as an indirect measure of subclinical mastitis was compared with CMT using the receiver operating characteristics curves. The udder skin surface temperature was positively correlated with the CMT score (r=0.86) and SCC (r=0.73). There was an exponential increase in SCC (SCC, x10(3) cells/mL=22.35 x e(1.31 x CMT score); R(2)=0.98) and a linear increase in USST (USST, degrees C=33.45+1.08 x CMT score; R(2)=0.75) as the CMT score increased. As SCC increased, USST increased logarithmically [USST, degrees C=28.72+0.49 x ln(SCC, x10(3) cells/mL); R(2)=0.72]. The USST for healthy quarters (SCC <or=400,000 cells/mL; n=94) was different from that for subclinical mastitic quarters (SCC >400,000 cells/mL; n=135) (mean +/- SE; 33.45+/-0.09 vs. 35.80+/-0.08 degrees C). The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value were 95.6, 93.6, 14.97, 0.05, 95.0, and 93.6, respectively, for IRT and 88.9, 98.9, 83.56, 0.11, 99.2, and 86.1, respectively, for CMT. The area under the receiver operating characteristics curve for IRT and CMT was not different. In conclusion, as a noninvasive and quick tool, IRT can be employed for screening subclinical mastitis via measuring USST, with a high predictive diagnostic ability similar to CMT when microbiological culturing is unavailable. However, the reliability of IRT among cows with different characteristics and those living under various environmental conditions remains to be determined.
[Show abstract][Hide abstract] ABSTRACT: Maltogenic amylases (MAases), a subclass of cyclodextrin (CD)-hydrolyzing enzymes, belong to glycoside hydrolase family 13. A gene corresponding to MA in Geobacillus caldoxylosilyticus TK4 (GcaTK4MA) was cloned into pET28a(+) vector and expressed in Escherichia coli with 6xHis-tag at the N-terminus. Herein, we report on the biochemical properties of a new thermo- and pH-stable MA. GcaTK4MA has similar properties those of other MAases in terms of the primary structure, preference for CD over starch and having an extra domain at its N- and C-terminals. The recombinant protein was purified efficiently by using one-step nickel affinity chromatography. The purified enzyme exhibited optimal activity for β-CD hydrolysis at 50 °C and pH 7.0. When the enzyme was separately incubated at 4 °C and 50 °C in the buffer solutions (pH 3.0–9.0) up to 7 days, it was seen that the enzyme had the higher stability at 50 °C than 4 °C. The enzyme retained about 80% of its original activity when it was incubated at 50 °C for 7 days. The enzyme activity was significantly inhibited by SDS and EDTA at the final concentration of 1%. These results suggest that this is the first reported MA having an extremely pH- and thermal stabilities.
PROCESS BIOCHEMISTRY 06/2010; 45(6-45):821-828. DOI:10.1016/j.procbio.2010.02.001 · 2.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Polyphenol oxidase (PPO) was purified from Boletus erythropus using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. Optimum pH and temperature were found to be 8.0 and 20 °C, respectively, using 4-methylcatechol as a substrate. The enzyme was extremely stable between pH 3.0 and 9.0 after 24 h incubation at 4 °C. B. erythropus PPO was also quite stable between 10 and 30 °C after 4 h incubation. The Km and Vmax values were calculated as 2.8 mM and 1430 U/mg protein by Lineweaver–Burk curve, respectively. The enzyme activity was inhibited by sodium metabisulfite, ascorbic acid, sodium azide and benzoic acid. It was seen that the mushroom PPO was an effective biocatalyst in selected organic solvents, such as dichloromethane, dichloroethane and toluene, when catechin was used as a substrate. All data support that B. erythropus has a highly active PPO, possessing similar biochemical and kinetic characteristics to other plant PPOs.
[Show abstract][Hide abstract] ABSTRACT: Introducción. En el desarrollo de daño secundario tras lesión medular están implicadas diversas caspasas. La terapia anti-caspasas ha utilizado como diana una sola caspasa que ha sido investigada en una gran variedad de estudios tanto in-vitro como in-vivo. Estos estudios han examinado el efecto neuroprotector del Q-VD-PPh, un inhibidor pan-caspasa, en un modelo de lesión medular en rata. Material y métodos. Se dividieron 30 ratas Wistar en tres grupos de 10 ratas cada uno: una lesión medular traumática (con un trauma de 40 g-cm) se realizó a nivel torácico grupo control (grupo 1), grupo trauma control (grupo 2) y el grupo de ratas tratadas con Q-VD-OPh (grupo 3) se realizó a nivel torácico (T8-T10) mediante la técnica de caída de peso. La respuesta a la lesión y los efectos neuroprotectores de Q-VD-OPh se valoraron mediante el examen histopatológico y la técnica de TUNEL 24 horas y 5 días tras el traumatismo. Se usó la prueba del plano inclinado de Rivlin y Tator y una versión modificada de la escala de Tarlov para valorar el resultado funcional de las ratas 24 horas, 3 días y 5 días tras la lesión. Resultado. Veinticuatro horas tras la lesión, el estudio histopatológico de las secciones obtenidas del grupo 2 revelaron hemorragia, necrosis, trombos vasculares y edema. Las secciones obtenidos del grupo 3 mostraron hallazgos similares en ese momento. 24 horas tras la lesión el número de células apoptóticas fue 4.47 ± 0.35 en el grupo 2 y 1.58 ± 0.33 en el grupo 3. Cinco días tras la lesión el número medio de células apoptóticas fue de 4.35 ± 0.47 en el grupo 2 y de 1.25 ± 0.34 en el grupo 3. De esta forma el número de células TUNEL positivas en la médula dañada se redujo de forma considerable con el tratamiento con Q-VD-OPh. La función neurológica (tanto con el plano inclinado como con las escalas motoras) fueron significativamente mejores en el grupo de ratas tratadas mediante Q-VD-OPh que en el grupo control. Conclusión. Los marcados efectos antiapoptóticos de la Q-VD-OPh debido a la inhibición de todas las caspasas hace que sea un agente prometedor.
[Show abstract][Hide abstract] ABSTRACT: Various caspases have been implicated in the development of secondary damage after spinal cord injury (SCI). Anticaspase therapy that targets only one caspase has been investigated in a variety of in vitro and in vivo studies. This study examined the neuroprotective effects of Q-VD-OPh, a pan-caspase inhibitor, in a rat model of SCI.
Thirty Wistar albino rats were divided into 3 groups of 10 each: the sham-operated controls (group 1), the trauma-created controls (group 2), and the QVD- OPh-treated rats (group 3). An SCI (a trauma of 40 g-cm) was produced at the thoracic level (T8-T10) by the weight-drop technique. The response to injury and the neuroprotective effects of Q-VD-OPh were investigated by histopathologic examination and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) 24 hours and 5 days after trauma. The inclined plane technique of Rivlin and Tator and a modified version of Tarlov's grading scale were used to assess the functional status of the rats 24 hours, 3 days, and 5 days after injury.
Twenty-four hours after trauma, light microscopic examination of a specimen taken from group 2 rats revealed hemorrhage, necrosis, vascular thrombi, and edema. Group 3 tissue samples showed similar features at that time. Twenty-four hours after trauma, the mean apoptotic cell number was 4.47 +/- 0.35 cells in group 2 and 1.58 +/- 0.33 in group 3. Five days after injury, the mean apoptotic cell count was 4.35 +/- 0.47 in group 2 and 1.25 +/- 0.34 in group 3. Thus the number of TUNEL-positive cells in an injured spinal cord was greatly reduced by treatment with Q-VDOPh. The neurologic function scores (both the inclined plane performance and motor grading scores) were significantly better in the Q-VD-OPh-treated group than in the trauma-created control group.
The marked antiapoptotic properties of Q-VD-OPh due to the inhibition of all caspases render it a promising novel agent. A therapeutic strategy using Q-VD-OPh may eventually lead to the effective treatment of SCI in humans.