综述抗菌肽的生物学功能

抗菌肽广泛存在于动物的免疫细胞、内脏黏膜、皮肤以及植物的花、果、叶中。早在1972年,瑞典科学家Boman等[1]首次用大肠杆菌和阴沟肠杆菌诱导惜古比天蚕蛹(Hyatophora cecropia),从其血淋巴中分离得到天蚕素抗菌肽。随后Boman等[2]又进一步测定了天蚕素抗菌肽A和B的一级结构,随后天蚕素抗菌肽相继被分离、纯化,并且其氨基酸的结构特征和基因序列得到确定。到目前为止,天蚕素抗菌肽共[3]     

天蚕素抗菌肽的研究与应用

抗菌肽是一类普遍存在于生物体内的天然免疫因子,具有广谱抗菌、抗病毒、抗肿瘤且不易形成耐药性和无药物残留等多种生物学特点。天蚕素是世界上发现最早的抗菌肽,也是至今为止研究得最为透彻的一类抗菌肽,更是最具潜力的抗生素替代品之一。文章综述了天蚕素抗菌肽的结构、来源、生物作用、表达体系等,并且重点介绍了天蚕素抗菌肽的应用,并对其存在的问题和未来发展前景进行了分析。     

饲料中添加天蚕素抗菌肽对湘云鲫生长性能、非特异性免疫功能及抗病力的影响(二)

(接《新饲料》2014年12期63页)2.2饲料中添加天蚕素抗菌肽对湘云鲫形体指数的影响表3所示为饲料中添加天蚕素抗菌肽对湘云鲫肥满度、肾脏指数、肝胰脏指数、内脏指数和脾脏指数的影响。经8周的饲养试验发现,添加150mg/kg天蚕素抗菌肽组肥满度显著高于空白对照组(P<0.05),与金霉素添加组和200mg/kg天蚕素抗菌肽组差异不显著(P>0.05),但是显著高于250mg/kg天蚕素抗菌肽组(P<0.05)。饲料中添加天蚕素抗菌肽对肾脏指数、肝胰脏     

天蚕素抗菌肽B在鱼类疾病控制中的应用

正抗菌肽是分子质量小、两亲性、带正电的非特异性物质~([1-2]),多为α螺旋结构,天蚕素是最早被发现的,目前研究最清晰,效果最显著的一类抗菌肽。早在1972年,瑞典科学家Boman等~([4])从美国希古比天蚕蛹(Hyalophoracecropia)中获得抗菌肽,并将其命名为Cecropin;随后,Boman等测定了天蚕素抗菌肽A (Cecropin A)和天蚕素抗菌肽B (Cecropin B)的一级结构~([4])。目前,天蚕素抗菌肽家族已被分为A、B、C、D、E共5个成员,其中Cecropin B具有最高的抗菌活性~([5-6])。     

天蚕素抗菌肽体外抑菌及肉鸡饲喂效果观察

为评估肉鸡日粮中添加抗菌肽替代抗生素的饲用效果,本试验先对1种天蚕素抗菌肽进行了体外抑菌试验,然后进行了肉鸡饲喂试验。用微量稀释法测定了天蚕素抗菌肽对大肠杆菌、沙门菌和金黄色葡萄球菌的最小抑菌浓度(minimal inhibitory concentration,MIC)。结果表明,天蚕素抗菌肽对大肠杆菌、沙门氏菌和金黄色葡萄球菌的MIC分别是20μg/mL、20μg/mL和40μg/mL。在肉鸡饲喂试验中,饲料中添加150mg/kg的天蚕素抗菌肽可以促进肉鸡生长,降低发病率。     

抗菌肽对海兰褐仔公鸡小肠黏膜形态结构及免疫活性细胞数量的影响

本试验旨在探讨饲粮中添加不同水平天蚕素抗菌肽对海兰褐仔公鸡小肠黏膜形态结构及免疫活性细胞数量的影响。选择336只1日龄健康海兰褐仔公鸡,随机分为7个处理,每个处理4个重复,每个重复12只鸡。7个处理分别为对照组(饲喂基础饲粮),抗生素组(150 mg/kg金霉素),抗菌肽Ⅰ(饲喂基础饲粮+150 mg/kg天蚕素抗菌肽)、Ⅱ(饲喂基础饲粮+200 mg/kg天蚕素抗菌肽)、Ⅲ(饲喂基础饲粮+250 mg/kg天蚕素抗菌肽)、Ⅳ(饲喂基础饲粮+300 mg/kg天蚕素抗菌肽)、Ⅴ组(饲喂基础饲粮+350 mg/kg天蚕素抗菌肽),饲养试验期为42 d。结果表明:各处理肠黏膜结构与对照组相比较完整,除十二指肠隐窝深度、空肠肌层厚度各处理之间无显著性差异(P>0.05)外,不同添加水平的抗菌肽组绒毛高度、黏膜厚度、肌层厚度均在一定程度上高于对照组,隐窝深度均在一定程度上低于对照组,抗菌肽Ⅴ组效果最为显著(P<0.05)。抗菌肽Ⅴ组空肠上皮内淋巴细胞数量显著高于对照组(P<0.05),抗菌肽Ⅲ、Ⅳ、Ⅴ组与对照组相比可显著提高十二指肠、空肠及回肠杯状细胞数量(P<0.05)。由此可见,饲粮添加天蚕素抗菌肽可显著改善海兰褐仔公鸡小肠黏膜上皮细胞形态,同时也增加了小肠免疫活性细胞的数量。其中抗菌肽Ⅴ组添加效果最好,天蚕素抗菌肽添加量为350 mg/kg。     

天蚕素抗菌肽对肉兔生产性能和免疫器官指数的影响

试验旨在研究天蚕素抗菌肽对新西兰兔生产性能和免疫器官指数的影响。选择160只35日龄断奶的新西兰肉兔,随机分为5个处理,每个处理4个重复,每个重复8只兔。对照组饲喂基础饲粮,试验组分别在基础饲粮基础上添加30 mg/kg喹乙醇、150、200 mg/kg和250 mg/kg天蚕素抗菌肽,试验期为8周。结果表明,天蚕素抗菌肽可一定程度提高肉兔的日增重,显著降低料重比(P<0.05),对肉兔的采食量无显著影响(P>0.05);添加天蚕素抗菌肽有增加肉兔脾脏和胸腺重量的趋势,添加200 mg/kg和250 mg/kg天蚕素抗菌肽可显著提高肉兔脾脏指数和胸腺指数(P<0.05)。由此可见,在肉兔饲粮中添加天蚕素抗菌肽,可提高肉兔生产性能,促进免疫器官发育,提高免疫器官指数。     

天蚕素抗菌肽的优势及应用新进展

抗菌肽是进化上高度保守、普遍存在的天然免疫系统因子,具有广谱抗菌、抗病毒、抗肿瘤等多种生物学活性,且不易形成耐药性和药物残留。天蚕素抗菌肽是最早被分离出的昆虫类抗菌肽,也是迄今为止研究的最为透彻的一类抗菌肽。研究表明,与天然抗菌肽相比,经过人工改造的杂合抗菌肽比天然抗菌肽具有稳定性好、抗菌谱广、活性更高等优点。文章对天蚕素抗菌肽的优势及其在畜牧生产中的应用新进展进行了综述。     

天蚕素抗菌肽CAD研究进展及其在畜牧生产中的应用

抗菌肽是进化上高度保守、普遍存在的天然免疫系统因子,具有广谱抗菌、抗病毒、抗肿瘤等多种生物学活性,且不易形成耐药性和药物残留。天蚕素抗菌肽是最早被分离出的昆虫类抗菌肽,也是迄今为止研究最为透彻的一类抗菌肽。研究表明,经过人工改造的杂合抗菌肽比天然抗菌肽具有稳定性好、抗菌谱广、活性高等优点。文章对天蚕素抗菌肽CAD的研究进展及其在畜牧生产中的应用进行了综述,以为其应用提供参考。     

抗菌肽天蚕素B基因的克隆及其在山羊乳腺中的暂态表达

根据已发表的天蚕素B的cDNA序列化学合成4务引物,以重叠延伸PCR的方法合成了真核细胞偏爱密码子编码的抗菌肽天蚕素B基因,将其克隆于pMD18-T栽体,DNA序列分析证实合成的抗菌肽基因的碱基序列与设计的序列完全一致.利用山羊-β酪蛋白基因5'侧翼调控序列和真核基因表达栽体plRES1-neo,构建抗菌肽天蚕素B的乳腺组织特异性表达载体pbCP-cpin,将该载体溶于生理盐水,注入处于泌乳期的成年母山羊乳腺组织进行暂时表达.通过对大肠杆菌、金黄色葡萄球菌的抑菌试验确定了抗菌肽天蚕素B基因在山羊乳腺中的表达和抗菌活性.本试验建立了抗菌肽天蚕素B的乳腺瞬时表达系统,为验证各调控元件以及抗菌肽基因在转基因动物乳汁中分泌表达的有效性和可行性提供了一个快速检测系统.     

Biofilms and their relevance to veterinary medicine

Bacteria are renowned for their ability to tolerate and adapt to a wide range of adverse environmental conditions. The primary mechanism that facilitates these adaptations is thought to be the capacity to form and maintain biofilms. Within a biofilm, bacteria become attached to a surface where they exist in complex communities which are able to interact with each other through intracellular communication and thus rapidly adapt to changing environments. The organisms within biofilms are notorious for their resistance towards the host immune response and antibacterial agents compared to their free-living planktonic counterparts. Consequently, biofilms are of significant importance to both clinical and veterinary science. However, although bacterial infections are widely reported in animals their association with biofilms is rarely discussed. The aim of this review is to look at the characteristics of biofilm infections in humans and to relate this knowledge to veterinary science in order to assess their relevance in this area.     

The diet of adult psittacids: veterinarian and ethological approaches

Parrots species are kept as pets because of their colours, their vocal abilities, their longevity and also their behaviours. Nevertheless, many owners do not know how to feed their bird in a healthy way and sometimes veterinarians and ethologists are confronted to dramatic situations. Diet is a key factor to prevent and reduce health and psychogenic disorders. Imbalance can lead to physical, physiological and behavioural modifications that can weaken the owner–bird relationship, cause bird discomfort and sometimes threaten its survival. Psittacids are known for their complex cognitive and communicative abilities. They are social animals and need many interactions. Kept in captivity, they could suffer from boredom because of lack of stimulations and also because of lack of possibility to explore and to forage, which could represent up to 70% of their day time in the wild. Indeed, humans control every parameter in the environment of pet psittacids. They provide a highly digestible diet. In captivity, foraging is not mandatory, and the bird can get bored. Here, we present a review of the literature regarding the quality of the diet and health disorders on one hand and the interaction between foraging opportunities and psychogenic disorders in adult psittacids on the other hand.     

当代大学新生挫折承受力及应对研究

人的一生会遇到很多挫折,怎样面对挫折将直接影响其身心发展。大学新生作为一个特殊群体,普遍自我评价高,期望值高。但由于社会经历浅,理想色彩浓,事实上他们的心理状况却不容乐观,他们常常会遇到各种各样的矛盾与挫折、出现诸多心理问题。在矛盾和挫折面前如何面对,将直接影响他们的身心发展。笔者就大学新生的挫折承受力状况、特征、因素进行了研究并提出了应对措施。     

抗菌肽在哺乳动物防御系统中的作用

抗菌肽是近年来发现的广泛存在于自然界的一类阳离子抗菌活性肽，它们在宿主先天性免疫和适应性免疫中有重要作用。多数抗菌肽具有分子小、带正电、两亲性、抗菌谱广等共同特点。防御素和calhelicidins是哺乳动物的两大主要抗菌肽家族，它们通过抵抗致病菌入侵为宿主提供了第一道防线而对宿主具有先天的抗菌防御功能，其中一些多肽对未分化的树突状细胞、淋巴细胞有趋化性，另外还有诱导细胞因子生成、肥大细胞脱粒等作用，从而表明这些多肽能动员并增强宿主的先天性免疫和适应性免疫。本文主要对哺乳动物抗菌肽的一般性质、基因及其表达、在宿主防御中的作用、作用机理及研究前景进行了概述。     

The role of female veterinarians in Africa

While the number of female veterinary students has reached figures as over 80% in the Netherlands and other European countries, the number of female veterinary students in Africa is also changing but still at a slower pace. Still nowadays, according to UNICEF, two-thirds of primary school age children, denied their right to basic education, are girls. In addition, especially in rural areas in Africa, there are only few secondary schools, so that children, either have to travel over large distances on a daily basis or have to live away from their families. As girls, already from an early age play an important role in the daily household routine, they are often not allowed to leave for schooling. There used to be less than 10 veterinary faculties in Africa during the first half of the 20th century. These faculties were located in South Africa, Sudan, Egypt and Nigeria. For many years, African veterinarians were also trained in western countries (UK, France, USA) or in former communist countries (Russia, Ukraine, Romania, Hungary Eastern Germany, Cuba) depending on the existence of historic or political links. A long stay abroad made it more difficult for female students, especially for those with children. Still nowadays, female veterinarians in Africa are mostly working for the veterinary departments mainly in the urban areas. Another area where many female veterinarians can be found are governmental diagnostic and research laboratories as well as training institutions such as veterinary faculties or agricultural colleges. Generally the salaries at these institutions are very low and therefore their male colleagues have gradually shifted to work in the private sector with more competitive salaries (private clinics, sector pharmaceutical companies, development projects, (agricultural) banks, etc). As still in most societies, women tend to follow their husbands, most female veterinarians are bound to find employment where their husbands are based. In addition, as most postgraduate training required a prolonged stay abroad, women encountered difficulties in leaving their families behind to improve their career perspectives. Gradually, there has been an increase of possibilities of post-graduate training in the African region as well as the introduction of a modular system and perspectives for training over the internet. These developments will clearly be beneficial for women, as it will enable them to follow post-graduate training without leaving their families for extended periods. Gradually, also female veterinarians in Africa are becoming empowered and recognise their capabilities. The understanding of the importance of gender aspects especially with regard to animal husbandry practices has opened up new opportunities for female veterinarians to work in extension services and as health promoters. The access to further education is the key to expanding their professional perspectives.     

A proposal of interpretive criteria for cefoperazone applicable to bovine mastitis pathogens

The correct assessment of mastitis pathogens for their susceptibility/resistance to cefoperazone is currently hampered by the lack of harmonized test conditions and interpretive criteria. The aim of this study was to provide a proposal for clinical breakpoints of cefoperazone which are applicable to Staphylococcus aureus, coagulase-negative staphylococci, Escherichia coli, Streptococcus agalactiae, Streptococcus dysgalactiae and Streptococcus uberis from cases of bovine mastitis and better reflect the situation in the bovine udder than breakpoints adopted from human medicine. For this, pharmacological data and clinical efficacy data of the documents submitted for approval of cefoperazone have been revisited. In addition, 1086 bacterial pathogens of the aforementioned six species/groups collected in Germany and in the USA during recent years were tested in parallel for their cefoperazone MICs and the zone diameters using a 75 μg disk. Subsequently, MICs were plotted against zone diameters. Based on the pharmacological data, the clinical efficacy and the microbiological data, a proposal was made for veterinary-specific breakpoints which classify members of the aforementioned species/groups as (a) susceptible to cefoperazone when their MIC is ≤ 2 μg/ml and their zone diameters are ≥ 27 mm (staphylococci or E. coli) or ≥ 21 mm (streptococci), (b) intermediate when their MIC is 4 μg/ml and their zone diameters are 22-26 mm (staphylococci or E. coli) or 16-20mm (streptococci), and (c) resistant when their MIC is ≥ 8 μg/ml and their zone diameters are ≤ 21 mm (staphylococci or E. coli) or ≤ 15 mm (streptococci).     

A review of the factors affecting the survival of donkeys in semi-arid regions of sub-Saharan Africa

The large fluctuations seen in cattle populations during periods of drought in sub-Saharan Africa are not evident in the donkey population. Donkeys appear to have a survival advantage over cattle that is increasingly recognized by smallholder farmers in their selection of working animals. The donkey's survival advantages arise from both socioeconomic and biological factors. Socioeconomic factors include the maintenance of a low sustainable population of donkeys owing to their single-purpose role and their low social status. Also, because donkeys are not usually used as a meat animal and can provide a regular income as a working animal, they are not slaughtered in response to drought, as are cattle. Donkeys have a range of physiological and behavioural adaptations that individually provide small survival advantages over cattle but collectively may make a large difference to whether or not they survive drought. Donkeys have lower maintenance costs as a result of their size and spend less energy while foraging for food; lower energy costs result in a lower dry matter intake (DMI) requirement. In donkeys, low-quality diets are digested almost as efficiently as in ruminants and, because of a highly selective feeding strategy, the quality of diet obtained by donkeys in a given pasture is higher than that obtained by cattle. Lower energy costs of walking, longer foraging times per day and ability to tolerate thirst may allow donkeys to access more remote, under-utilized sources of forage that are inaccessible to cattle on rangeland. As donkeys become a more popular choice of working animal for farmers, specific management practices need to be devised that allow donkeys to fully maximize their natural survival advantages.     

The Fine Structure of the Fundic Stomach Epithelium of the Western Newt

The effects of varying intensities of histamine stimulation on cells of the western newt fundic stomach epithelium have been studied. Oxyntic, mucous neck and surface mucous cells all secrete. In the oxyntic cell, the main effects are a movement of zymogen granules toward the apex, the discharge of their contents into the lumen and, eventually, their disappearance from the cytoplasm. Additionally, the tubular membrane elements (tubulo- vesicles) fuse with the apical plasma membrane with a corresponding reduction in their numbers and an increase in microvilli, which eventually are so numerous as to virtually occlude the lumina of gastric glands. Total histamine stimulation results in apparent damage to the oxyntic cells. Mucous neck and surface mucous cells release their mucigen droplets by exocytosis and are grossly changed in appearance also.     

Homemade diets: attributes, pitfalls, and a call for action

At one time, it was estimated that the majority of dogs and cats in the United States received 90% or more of their nutrition from complete and balanced commercially prepared foods, and this estimate was reaffirmed in a 2004 survey. However, 4 years and several pet food and treat recalls later, fewer pet owners are feeding commercial pet food products exclusively and more are asking questions and looking for alternatives. As in any market-driven economy, there are many more alternative diets and food products available today from which pet owners may select. A difficult to measure but growing number of clients are feeding homemade diets that provide 100% of their pet's nutrition, while a larger number are feeding a combination of products, treats, and home prepared meals. Most practitioners can attest to this increase in their client's interest in homemade meals and to having insufficient knowledge to assist them. At a time when motivated clients are considering homemade for their pets as an alternative, veterinarians are less than adequately versed in canine and feline nutrition and dietary options. The article addresses the two most important health issues concerning pet owners and veterinarians about homemade diets: nutritional integrity and food safety.     

家畜体内防御素多态性和表达的研究进展

抗菌肽可抵御细菌、病毒和真菌的入侵,在人类和家畜的先天性防御系统中具有重要的作用,是有望用于预防和治疗的药物,因此,抗菌肽被称为"新一代的抗生素"。抗菌肽是一个阳离子肽,其中的一个大家族就是防御素。防御素的结构中普通带有一个β-片状结构,其中包含3个分子内二硫键,可分为α-防御素、β-防御素和θ-防御素,其中β-防御素是最大的一个家族,在人类和家畜的组织内均有表达。结合已有的研究成果,作者主要对家畜体内防御素的表达、多态性及其作为健康和生产性能的遗传标记的潜在应用作一综述。