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关键词： Feather degradation   Bacillus pumilus   Keratinase   DMSO   Feather meal   Modified minimal medium  

摘要： The increasing amount of recalcitrant keratinous wastes generated from the poultry industry poses a serious threat to the environment. Keratinase have gained much attention to convert these wastes into valuable products. Ever since primitive feathers first appeared on dinosaurs, microorganisms have evolved to degrade this most recalcitrant keratin. In this study, we identified a promising keratinolytic bacterial strain for bioconversion of poultry solid wastes. A true keratinolytic bacterium was isolated from the slaughterhouse soil and was identified and designated as Bacillus pumilus AR57 by 16S rRNA sequencing. For enhanced keratinase production and rapid keratin degradation, the media components and substrate concentration were optimized through shake flask culture. White chicken feather (1% w/v) was found to be the good substrate concentration for high keratinase production when supplemented with simple medium ingredients. The biochemical characterization reveals astounding results which makes the B. pumilus AR57 keratinase as a novel and unique protease. Optimum activity of the crude enzyme was exhibited at pH 9 and 45 degrees C. The crude extracellular keratinase was characterized as thermo-and-solvent (DMSO) stable serine keratinase. Bacillus pumilus AR57 showed complete degradation (100%) of white chicken feather (1% w/v) within 18 h when incubated in modified minimal medium supplemented with DMSO (1% v/v) at 150 rpm at 37 degrees C. Keratinase from modified minimal medium supplemented with DMSO exhibits a half-life of 4 days. Whereas, keratinase from the modified minimal medium fortified with white chicken feather (1% w/v) was stable for 3 h only. Feather meal produced by B. pumilus AR57 was found to be rich in essential amino acids. Hence, we proposed B. pumilus AR57 as a potential candidate for the future application in eco-friendly bioconversion of poultry waste and the keratinase could play a pivotal role in the detergent industry. While feather meal m

关键词： Tridacna crocea   Giant clam   Light intensity   Growth   Biochemical composition  

摘要： Giant clams are able to grow in oligotrophic tropical marine environments with the aid of photosynthates from its symbiotic zooxanthellae. Therefore, light intensity affects the survival and growth of giant clams, and is one of the most important environmental factors in giant clam cultures. In this study, two size classes of Tridacna crocea (small: similar to 50mm shell length, large: similar to 85mm shell length) were cultured at three light intensities (5000, 10,000, and 15,000 lx) for 16 weeks, to evaluate the effects of light intensity on the survival, growth performance and biochemical composition of different size clams. T. crocea under 15,000 lx light intensity showed a significantly higher survival rate and relative growth rate (RGR) (P <.0001). The RGR in the small group was significantly higher than the large group under 10,000 and 15,000 lx light intensity (P <.0001), while higher RGR was observed in the large group under 5000 lx light intensity (P=.0009). The content of eight amino acids in the mantle was significantly affected by light intensity (P <.05), while only one amino acid (glycine) was found in the adductor muscle (P=.0005). Similarly, there were significant differences in ten mantle amino acids between small and large size groups (P <.05), while three amino acids were found in the adductor muscle (P <.05). C22:6n3 (DHA) was the major polyunsaturated fatty acid (PUFA) in T. crocea. In the adductor muscle, the C22:6n3 profile significantly increased with increasing light intensity and clam size (P <.0001), while no significant differences of C22:6n3 profiles were found among different light intensities in the mantle (P=.3345). Our results demonstrate that a light intensity of 15,000 lx is suitable for T. crocea (45-90mm in shell length) rearing, and that large size T. crocea has higher tolerance to weak light intensity than small individuals.

关键词： Miscanthus   Stem fragments   Genotype   Thermal properties   Mechanical properties  

摘要： The thermal and dynamic mechanical properties of miscanthus stem fragments and differences between genotypes and positions along the stem are studied in relation with their biochemical and structural characteristics. The starting degradation temperature does not correlate to the biochemical composition. However, the first DTG peak temperature is negatively correlated to hemicelluloses content and positively correlated to lignin and pcoumaric contents. A pronounced genotypic effect is evidenced on fragments elastic moduli while limited effect of the position along the stem is found. This is mostly related to ferulic and p-coumaric acid contents of stem fragments for which a strong correlation to elastic moduli is evidenced. Our results highlight that genotypic effect, position along the stem, stem fragment dimensions and mechanical properties of miscanthus stem fragments are strongly interconnected in relation with their respective biochemical and structural characteristics. This opens interesting perspectives for identifying key biological traits that need to be optimized for a better selection of performing miscanthus genotypes targeted to polymer composite applications.

关键词： ERK3   Mitogen activated protein kinase   Kinase inhibitor   Protein crystal structure   Cellular NanoBRET assay  

摘要： Triazolo[4,5-d]pyrimidin-5-amines were identified from kinase selectivity screening as novel ERK3 inhibitors with sub-100 nanomolar potencies in a biochemical assay using MK5 as substrate and with an attractive kinase selectivity profile. ERK3 crystal structures clarified the inhibitor binding mode in the ATP pocket with impact on A-loop, GC-loop and alpha C-helix conformations suggesting a potential structural link towards MK5 interaction via the FHIEDE motif. The inhibitors also showed sub-100 nM potencies in a cellular ERK3 NanoBRET assay and with excellent correlation to the biochemical IC(50)s. This novel series provides valuable tool compounds to further investigate the biological function and activation mechanism of ERK3.

关键词： Microalgae   Feed additive   Danio rerio   Enzymatic activity  

摘要： Protein-rich microalgae are a potential alternative to fishmeal in aquaculture. In this context, this study evaluated the effects of fish meal (FM) replacement by Chlorella sp. meal (CM) on the growth performance, bio-chemical parameters, enzymatic activity and reproductive performance of zebrafish (Danio rerio). Six experimental diets were formulated to progressively replace FM. Up to 100% of FM was replaced with CM content at 0, 10, 20, 30, 40 and 50 g/kg diet. A total of 450 zebrafish were randomly divided into six groups, each group containing five replicates with 15 animals per replicate. After 60 days of feeding trials, animals fed 40 g/kg CM showed significantly better growth compared to animals fed diets with no CM. Likewise, animals fed 50 g/kg of CM presented the lowest levels of total cholesterol, LDL and triglycerides. The inclusion of CM had no significant effects on enzymatic amylase and lipase activity, while significantly increasing alkaline phosphatase activity. The highest levels of Chlorella sp. meal in the diets (40 and 50 g/kg of CM) provided the highest egg production (P = .004), hatching rate (P = .004) and larval survival (P = .009) at 6 days post-fertilization. The replacement of FM by CM generated an increase in the final weight, accompanied by an improvement in total cholesterol, LDL, triglyceride levels, in addition to improving the reproductive performance of zebrafish, proving to be an interesting alternative to FM in zebrafish juvenile diets.

关键词： Essential fatty acid   Serum biochemical parameters   Antioxidant response   Lipid metabolism   Onychostoma macrolepis  

摘要： This study was conducted to elucidate effects of dietary essential fatty acid requirements on the growth, physiological characteristics and expressions of some lipid-related genes in juvenile Onychostoma macrolepis. Seven isonitrogenous and isoenergetic purified diets containing tristearin (control group), 2% linoleic acid (LA), 2% alpha-linolenic acid (LNA), 1% LA + 1% LNA, 1% eicosapentaenoic acid (EPA), 1% docosahexaenoic acid (DHA) and 0.5% EPA + 0.5% DHA were formulated to feed juvenile *** (initial body weight:1.51 +/- 0.05 g) for eight weeks. The weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of the fish were significantly higher in the LNA group and the EPA + DHA group than in the control group (P < .05). The growth and feed utilization of the fish in the LNA group were similar to those in the EPA + DHA group. The highest levels of 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3 in muscle and liver were found in the LA group, the LNA group, the EPA group and the DHA group, respectively. The highest concentrations of serum cholesterol (CHOL) and triglyceride (TG) were observed in the fish fed on the LA diet, and there were no significant differences in serum CHOL and TG between the LA group and the LA + LNA group. Serum malondialdehyde (MDA) content was observed to be the highest in the EPA group, DHA group and EPA + DHA group, and significantly higher in the these groups than in the other groups (P < .05). In liver, the superoxide dismutase (SOD) activities and the malondialdehyde (MDA) content were found to be significantly the lowest and the highest in the EPA, DHA and EPA + DHA groups (P < .05). The body fat content of the fish fed on the LA diet was significantly higher than those of the control ones (P < .05). The fatty acid synthetase (FAS), acetyl-CoA carboxylase 1(ACC1) and sterol regulatory element binding protein-1 (SREBP-1) genes involved in the anabolic pathway had the highest ex-pression levels in the LA group. The adipose

关键词： Hepatic glycolysis and lipogenesis   Blood biochemistry   Offshore sea cage   recirculating aquaculture system   Tiger puffer Takifugu rubripes  

摘要： Tiger puffer (Takifugu rubripes) is one of the most commercially important fish species cultivated and consumed in East Asian countries, including Japan, South Korea and China. In this study, the hepatic glycolysis, and lipogenesis, and serum biochemistry of tiger puffers subjected to short-term culture in offshore sea cage aquaculture system (OSCS) and recirculating aquaculture system (RAS) were evaluated. Results showed that the activity of hepatic phosphofructokinase, and lipoprotein lipase, ATP level, and serum cortisol content of the male tiger puffers reared in OSCS were significantly higher than those of female tiger puffers reared in OSCS and those of fish reared in RAS. The lowest hepatic fatty acid synthetase activity, lipid droplet number, serum aspartate aminotransferase activity, Na+ and Cl- concentrations were observed in male tiger puffers reared in OSCS. However, serum glucose, triglyceride, total cholesterol, K+ concentrations and alanine aminotransferase activity of tiger puffers reared in RAS and OSCS showed no significant differences. Hepatic glycolysis and lipogenesis were profoundly affected by rearing system and gender. The interaction effect of gender and rearing system on hepatic lipoprotein lipase activity, lipid droplet number and serum Na+ level was observed. These results indicate male tiger puffers exhibited different metabolic status in hepatic glycolysis, lipogenesis, and serum biochemical parameters when reared under two different culture systems. These findings will provide important information for improving tiger puffer (Takifugu rubripes) farming and profitable production using the RAS and OSCS aquaculture systems in the north coast of China.

关键词： Hepatectomy   Liver reserve function   ICG clearance test   ICG 15    min retention rate  

摘要： Background The indocyanine green (ICG) clearance test is the main method of evaluating the liver reserve function before hepatectomy. However, some patients may be allergic to ICG or the equipment of ICG clearance test was lack, leading to be difficult to evaluate liver reserve function. We aim to find an alternative tool to assist the clinicians to evaluate the liver reserve function for those who were allergic to the ICG or lack of equipment before hepatectomy. Methods We retrospected 300 patients to investigate the risk factors affecting the liver reserve function and to build an equivalent formula to predict ICG 15 min retention rate (ICG-R15) value. Results We found that the independent risk factors affecting ICG clearance test were total bilirubin, albumin, and spleen-to-non-neoplastic liver volume ratio (SNLR). The equivalent formula of the serological index combining with SNLR was: ICG-R15 = 0.36 x TB (umol/L) - 0.78 x ALB(g/L) + 7.783 x SNLR + 0.794 x PT (s) - 0.016 x PLT(/10(9)) - 0.039 x ALT (IU/L) + 0.043 x AST (IU/L) + 23.846. The equivalent formula of serum index was: ICG-R15(2) = 24.665 + 0.382 x TB (umol/L) - 0.799 x ALB(g/L) - 0.025 x PLT(/10(9)) + 0.048 x AST(IU/L) - 0.045 x ALT(IU/L). And the area under the ROC curve (AUC) of predicting ICG-R15 >= 10% was 0.861 and 0.857, respectively. Conclusion We found that SNLR was an independent risk factor affecting liver reserve function. Combining with SNLR to evaluate the liver reserve function was better than just basing on serology.

关键词： Immobilization   SiO2 nanoparticles   Lipase   PVA/alginate hydrogel   Enzyme reusability  

摘要： In this study, the factors affecting lipase adsorption onto SiO2 nanoparticles including SiO2 nanoparticles amounts (8, 19 and 30 mg/mL), lipase concentrations (30, 90 and 150 mu g/mL), adsorption temperatures (5, 20 and 35 degrees C) and adsorption times (1, 12.5 and 24 h) were optimized using central composite design. The optimal conditions were determined as a SiO2 nanoparticles amount of 8.5-14 mg/ml, a lipase concentration of 106-116 mu g/mL, an adsorption temperature of 20 degrees C and an adsorption time of 12.5 h, which resulted in a specific activity and immobilization efficiency of 20,000 (U/g protein) and 60 %, respectively. The lipase adsorbed under optimal conditions (SiO2-lipase) was entrapped in a PVA/Alg hydrogel, successfully. FESEM and FTIR confirmed the two-step method of lipase immobilization. The entrapped SiO2-lipase retained 76.5 % of its initial activity after 30 days of storage at 4 degrees C while adsorbed and free lipase retained only 43.4 % and 13.7 %, respectively. SiO2-lipase activity decreased to 34.43 % after 10 cycles of use, while the entrapped SiO2-lipase retained about 64.59 % of its initial activity. Compared to free lipase, the Km values increased and decreased for SiO2-lipase and entrapped SiO2-lipase, respectively. V-max value increased for both SiO2-lipase and entrapped SiO2-lipase.