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关键词： Feed additive   Growth   Haematocrit   Lipase   Lysozyme  

摘要： This study examined the growth, biochemical and haematological variables of Nile tilapia juveniles (Oreochromis niloticus) fed diets incorporated with essential oil from Aloysia triphylla (EOAT). Five diets were formulated;each containing increasing levels of EOAT (0.00 [control], 0.25, 0.50, 1.00 and 2.00 mL kg diet(-1)) for 45 days. Blood and intestinal samples of three fish per replicate (n = 4) were taken at the end of the experiment. Fish survival did not differ between treatments (p > .05). Positive linear effects of dietary EOAT supplementation on the final weight, weight gain and specific growth rate (R-2 = 0.73) and haematocrit (R-2 = 0.75) and erythrocytes (R-2 = 0.85) levels in fish, were observed (p < .05). The addition of 2.00 mL EOAT kg diet(-1) increased the intestinal lipase and alkaline protease activities, plasma alanine aminotransferase and albumin levels, the albumin to globulin ratio and lysozyme activity, and decreased the intestinal amylase activity, plasma glucose, triglycerides and globulin levels compared with the control group (p < .05). Thus, 2.00 mL EOAT kg diet(-1) is recommended for use in feed, since it ensures Nile tilapia growth, intestinal lipase and alkaline protease activities, plasma lysozyme and albumin levels, and haematocrit and erythrocyte values.

关键词： Polystyrene microplastic   Transcription   Transcriptome   Zebrafish  

摘要： Microplastics (MPs), which are new types of environmental pollutants, have recently received widespread attention worldwide. MPs can accumulate in the bodies of animals and in plants, and they can also enter the human body through the food chain. However, knowledge of the effects of MPs on the health of animals is still limited. In this experiment, adult male zebrafish were exposed to 20 or 100 mu g/L of 5 mu m polystyrene MP for 21 days in an attempt to determine the hepatic effects related to glycolipid metabolism at the biochemical and transcriplomic levels. It was found that body weight and condition factor decreased significantly in zebrafish after exposure to 20 and 100 mu g/L polystyrene MP for 21 days. The transcription levels of major genes related to glycolipid metabolism decreased significantly in the liver. Correspondingly, the levels of major biochemical parameters, including Glu, pyruvic acid, alpha-ketoglutaric acid and IDH, were also decreased in the livers of exposed zebrafish, especially those in the 100 mu g/L polystyrene MP-treated group. Moreover, the data on the hepatic transcriptome also confirmed that some genes related to fatty add metabolism, amino acid metabolism and carbon metabolism tended to be decreased in the livers of exposed zebrafish. Taken together, our data confirmed that polystyrene PS-MP can induce hepatic glycolipid metabolism disorder at the physiological, biochemical, and transcriptomic levels in adult zebrafish after 21 days of exposure. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Enzyme-linked immunoassays   Immune response   Antigens   Antibodies   Immunologic adjuvants   Red blood cells   Cholera   Vaccines  

摘要： Surface-expressed colonization factors and their subunits are promising candidates for inclusion into a multivalent vaccine targeting enterotoxigenic Escherichia coli (ETEC), a leading cause of acute bacterial diarrhea in developing regions. However, soluble antigens are often poorly immunogenic in the absence of an adjuvant. We show here that the serum immune response to CfaE, the adhesin of the ETEC colonization factor CFA/I, can be enhanced in BALB/c mice by immunization with a chimeric antigen containing CfaE and pentameric cholera toxin B subunit (CTB) of cholera toxin from Vibrio cholerae. We constructed this antigen by replacing the coding sequence for the A1 domain of the cholera toxin A subunit (CTA) with the sequence of donor strand complemented CfaE (dscCfaE) within the cholera toxin operon, resulting in a dscCfaE-CTA2 fusion. After expression, via non-covalent interactions between CTA2 and CTB, the fusion and CTB polypeptides assemble into a complex containing a single dscCfaE-CTA2 protein bound to pentameric CTB (dscCfaE-CTA2/CTB). This holotoxin-like chimera retained the GM1 ganglioside binding activity of CTB, as well as the ability of CfaE to mediate the agglutination of bovine red blood cells when adsorbed to polystyrene beads. When administered intranasally to mice, the presence of CTB in the chimera significantly increased the serum immune response to CfaE compared to dscCfaE alone, stimulating a response similar to that obtained with a matched admixture of dscCfaE and CTB. However, by the orogastric route, immunization with the chimera elicited a superior functional immune response compared to an equivalent admixture of dscCfaE and CTB, supporting further investigation of the chimera as an ETEC vaccine candidate.

关键词： Trachinotus ovatus   Stocking density   Growth   Biochemistry   Muscle quality   HSP70  

摘要： Golden pompano (Trachinotus ovatus) is one of the most important cultured marine fish in Southeast Asia. Stocking density affects the growth performance and welfare of fish in aquaculture. A 70-day rearing experiment was performed to evaluate the effect of different stocking densities on the growth performance, feed conversion ratio, serum biochemistry, muscle quality, antioxidant capacity and HSP70 mRNA expression of juvenile golden pompano cultured in off-shore sea cages. The experimental design was completely randomized using three replications with three treatments: low (100 fish/m(3)), medium (200 fish/m(3)), and high (300 fish/m(3)) stocking densities. Fish growth decreased significantly, and the feed conversion ratio increased significantly with increasing stocking density (P < .05). The serum glucose concentration increased significantly (P < .05), and the total protein, total triglyceride and total cholesterol concentrations were significantly reduced with increasing stocking density (P < .05). High stocking density led to elevated serum cortisol levels and decreased thyroxine levels. There was a significant decrease in the muscular crude fat content with increasing stocking density (P < .05), while the moisture, ash and protein contents did not significantly differ among the groups (P > .05). In this experiment, superoxide dismutase, glutamine transaminase and total antioxidant capacity increased significantly with increasing stocking density (P < .05). The expression levels of heat shock protein 70 were significantly up-regulated in the liver, kidney and brain as stocking density increased (P < .05);however, there was no significant difference in the spleen (P > .05). Overall, high stocking density was a chronic stressor in this experiment and had a negative effect on the growth, feed conversion ratio and animal welfare of T. ovatus.

关键词： Bacteriocins   Pneumococcus   Streptococcus   Antibiotics   Polymerase chain reaction   Molecular mass   Gene prediction   Protein sequencing  

摘要： Streptococcus pneumoniae infections are one of the major causes of morbility and mortality worldwide. Although vaccination and antibiotherapy constitute fundamental and complementary strategies against pneumococcal infections, they present some limitations including the increase in non-vaccine serotypes and the emergence of multidrug-resistances, respectively. Ribosomally-synthesized antimicrobial peptides (i.e. bacteriocins) produced by Lactic Acid Bacteria (LAB) may represent an alternative or complementary strategy to antibiotics for the control of pneumococal infections. We tested the antimicrobial activity of 37 bacteriocinogenic LAB, isolated from food and other sources, against clinical S. pneumoniae strains. Streptococcus infantarius subsp. infantarius LP90, isolated from Venezuelan water-buffalo milk, was selected because of its broad and strong anti-pneumococcal spectrum. The in vitro safety assessment of S. infantarius LP90 revealed that it may be considered avirulent. The analysis of a 19,539-bp cluster showed the presence of 29 putative open reading frames (ORFs), including the genes encoding 8 new class II-bacteriocins, as well as the proteins involved in their secretion, immunity and regulation. Transcriptional analyses evidenced that the induction factor (IF) structural gene, the bacteriocin/IF transporter genes, the bacteriocin structural genes and most of the bacteriocin immunity genes were transcribed. MALDI-TOF analyses of peptides purified using different multichromatographic procedures revealed that the dairy strain S. infantarius LP90 produces at least 6 bacteriocins, including infantaricin A(1), a novel anti-pneumococcal two-peptide bacteriocin.

关键词： 生物化学   融入   构建   营养学   联系   共通  

摘要： 中职护理专业由于各种原因未开设专门的营养学课程,导致该层次学生在营养学方面的学习存在诸多不确定因素,进而影响其临床整体护理的质量。在生物化学的相关课程中融入营养学知识,是目前解决此矛盾的有效途径,尤其是生物化学与营养学,在知识结构及学科体系的发展进程上,都有着联系甚至是共通之处。在生物化学教学过程中,以知识体系为导向,引导学生了解营养学基本内容,初步构建营养学基本框架,不仅能将枯燥、抽象的生物化学理论知识与营养学实际应用结合起来,提高生物化学教学效果,还能利用课程体系的重组和优化,树立学生在护理工作中重视营养知识学习的主观能动性,对解决人才培养中营养学教学薄弱的实际问题具有重要的现实意义。

关键词： 高职教育   教学改革   说课   教学效果策略  

摘要： 近年来,随着高职教育普及化,高职医学院校教学改革中涌现出许多的新生事物。说课就是教师面对同行或专家,用语言和相关辅助方法对某一教学环节或某节课的设计及其依据进行阐述,互相探讨达到共同提高的一种教研活动,说课能有效地提高教师专业素质、教育质量和教学效果。通过这种教研活动教师可以充实备课环节,切实提高专业素养和授课质量。本文以《生物化学》中实验课—酶的特异为例,从教学设计、教材分析、教学方法、教学目标、教学评价、教学效果等环节进行分析阐述,希望通过这种方式改善生物化学课程的教学效果策略。

关键词： covalent inhibitors   deubiquitinase   enzyme inhibition   hydrolases   structural biology  

摘要： The deubiquitinase (DUB) ubiquitin C-terminal hydrolase L1 (UCHL1) is expressed primarily in the central nervous system under normal physiological conditions. However, UCHL1 is overexpressed in various aggressive forms of cancer with strong evidence supporting UCHL1 as an oncogene in lung, glioma, and blood cancers. In particular, the level of UCHL1 expression in these cancers correlates with increased invasiveness and metastatic behavior, as well as poor patient prognosis. Although UCHL1 is considered an oncogene with potential as a therapeutic target, there remains a significant lack of useful small-molecule probes to pharmacologically validate in vivo targeting of the enzyme. Herein, we describe the characterization of a new covalent cyanopyrrolidine-based UCHL1 inhibitory scaffold in biochemical and cellular studies to better understand the utility of this inhibitor in elucidating the role of UCHL1 in cancer biology.

关键词： 动物生物化学   教学改革   应用创新  

摘要： 动物生物化学是一门基础知识比较多的学科,该学科的特性决定了其具有理论知识难度较大的特点。如果要改进动物生物化学理论教学存在的问题,就必须要从教学内容、教学方法、学生考核办法等各方面进行全面分析和研究。为了使学生能够更好地自主学习并且能够熟练掌握和运用相关基础理论知识,对该学科理论基础知识的教学改革方案进行了研究,旨在探索一套适合动物生物化学专业的教学方法,以提升动物生物化学的教学质量。