林蛙皮生物活性肽3种提取方法的比较研究

为了高效提取林蛙皮生物活性肽,试验采用甲醇提取法、超声波提取法、超声波辅助Alcalase蛋白酶酶解法进行比较研究。结果表明:超声波辅助Alcalase蛋白酶酶解法的提取效果最好,提取条件为加入Alcalase蛋白酶1.5 g,酶解温度为40℃,酶解时间为4 h。     

牛胸膜肽的提取及活性检测

为了探讨一种简便、快速、收获率高，适于大量提取的胸腺肽制备方法，在分析国内外报道的方法的基础上，确定了4种提取流程，对其收获率，所获提取物的活性进行鉴定和比较，同时对FA组分在鸡的新城疫病毒（NDV）和传染性喉气管炎（简称传喉）病毒（ILTV）混合感染中的防治作用进行了初步试验。为其在兽医临床的应用提供了试验依据。     

法氏囊活性肽的研究进展

法氏囊活性肽（囊素）是目前法氏囊组织提取物中唯一一种化学组成已被确定的活性因子，近十年来，对囊素的研究工作取得了很大进展。本文对囊素的生物学活性、组织定位、作用机制及其应用前景进行了综述。     

几种免疫活性肽的研究进展

免疫活性肽的研究始于1981年,Jolles等首次报道。用胰蛋白酶水解人乳蛋白,从水解产物中分离得到一种具有免疫活性的肽段。这个短肽在体外试验中能增强小鼠腹腔巨嗜细胞对绵羊红细胞的吞噬作用;静脉注射,则能增强小鼠抗肺炎克氏杆菌感染的能力。此后,科学家进行了大量免疫活性肽方面的研究,具有不同生物学功能的免疫活性肽相继被报道,如抗血栓转化酶抑制肽、酪蛋白磷酸肽、抗菌肽等。免疫活性肽能够刺激机体淋巴细胞的增殖,增强巨嗜细胞的吞噬功能,进而提高机体抵御外界病原体感染的能力,降低机体发病率,并具有抗肿瘤功能[1]。本文就近年研…     

那西肽的生物学活性及其应用进展

那西肽是一种含硫多肽类抗生素。它具有抗病毒、抗细菌和促进畜禽生长等作用,是畜禽专用饲用抗生素。由于用量低,无残留,对环境影响小,已经成为抗生素领域的研究热点,具有广阔的应用前景。现对那西肽的理化性质、生物学活性及其在临床上的应用进展等进行综述。     

免疫活性肽的研究进展

免疫活性肽是源于蛋白质的多功能化合物,具有促进和调节免疫功能的作用;其以活性高、来源广、稳定性强等优点受到国内外的广泛关注,并进行了大量的探究与试验。作者对不同来源的各种活性肽作一概述。     

乳源生物活性肽的研究进展

笔者介绍了乳源生物活性肽中阿片肽、阿片拮抗肽、降血压肽、抗血栓肽、免疫调节肽、酪蛋白磷酸肽及抗菌肽的化学结构和生物学作用,以期为生物活性肽的研发提供参考。     

鱼源宿主防御肽生物学活性及其潜在应用

宿主防御肽(HDPs)是动物机体先天免疫系统的重要组成部分,具有分子质量小、热稳定性好和不易产生耐药性等特点.作为极具潜力的抗生素替代物,HDPs不仅具有抗细菌、抗真菌和抗病毒等生物学活性,还具有多种免疫调节功能.鱼类是HDPs的重要来源,然而除小部分鱼源HDPs被用于抗菌活性研究外,其余鱼源HDPs的潜在应用还未被深...     

家蝇抗菌肽的分离纯化及生物学活性

将诱导家蝇提取的家蝇抗菌肽提取物，经凝胶过滤层析和离子交换层析，得到具有抗菌活性的单一峰，质谱结果显示抗菌肽分离物含有4种小肽，相对分子质量678．3～1017．2。家蝇抗菌肽对革兰氏阴性菌（大肠杆菌、巴氏杆菌）的抗菌活性优于革兰氏阳性菌（金黄葡萄球菌、枯草芽孢杆菌），对耐药性巴氏杆菌有较强的抗菌活性，对大肠杆菌的MIC为4．2～8．4mg／L，对耐药性巴氏杆菌的MIC为3．8～7．8mg／L。扫描电镜观察发现，家蝇抗菌肽通过损伤细胞壁使细胞质外流而达到杀菌的目的。家蝇抗菌肽对家兔、鸡、猪、小鼠、番鸭、鹅和家鸭红细胞无溶血反应和凝集反应。‘     

牛蛙(Rana catesbeiana)蛙皮抗菌肽基因的克隆、测序及其表达

利用RT—PCR的方法从牛蛙皮肤组织中克隆到大小为270bp的片段RCABP，将其克隆到pGEM—T载体，测序获得1个新的碱基序列。将此基因克隆到原核表达载体pQE一80L，获得融合表达质粒pQE一80L／DHFR／ABP，在1％IPTG诱导下进行表达。SDS—PAGE检测表明，重组蛙皮抗菌肽蛋白的表达量占菌体总蛋白的24％，以包涵体形式存在。体外抑菌试验表明，所构建的质粒能在大肠杆菌中表达具有体外抑菌活性的蛙皮抗菌肽，该融合蛋白具有良好的应用前景。     

唐古特莨菪中生物碱的分离、鉴定与生物活性研究

研究唐古特莨菪中生物碱对农业害虫(螨)的生物活性,可为利用该植物研制新型植物源杀虫(螨)剂提供理论依据。本文采用柱色谱分离法从唐古特莨菪地上部分分离得到2个生物碱类化合物,通过MS、NMR确定了其化学结构,分别为莨菪碱、东莨菪碱。采用微量点滴法和玻片浸渍法测定了莨菪碱、东莨菪碱对甘蓝蚜、桃蚜等9种蚜虫和朱砂叶螨、二斑叶螨等4种叶螨的触杀活性。结果表明,莨菪碱对禾谷缢管蚜、桃粉蚜、豆蚜和绣线菊蚜具有较强的触杀作用,LC₅₀值分别为257.863,275.459,344.645和344.717 mg/L。东莨菪碱对豆蚜和禾谷缢管蚜具有较强的触杀作用,LC₅₀值分别为311.585和392.309 mg/L。对照药剂鱼藤酮对甘蓝蚜和棉蚜具有较强的触杀作用,LC₅₀值分别为399.542和436.124 mg/L。对甘蓝蚜等9种蚜虫的触杀作用,莨菪碱强于或与东莨菪碱相当;对豆蚜、禾谷缢管蚜的触杀作用,莨菪碱和东莨菪碱均强于鱼藤酮;对甘蓝蚜、桃蚜和棉蚜的触杀作用,莨菪碱和东莨菪碱均弱于鱼藤酮。莨菪碱和东莨菪碱对截形叶螨、山楂叶螨、二斑叶螨和朱砂叶螨具有较强的触杀作用。2种生物碱对4种叶螨的毒力相当,对二斑叶螨和朱砂叶螨的毒力(201.027~224.172 mg/L)均高于截形叶螨和山楂叶螨(257.014~332.698 mg/L)。对照药剂鱼藤酮对截形叶螨、山楂叶螨的LC₅₀值分别为196.847和224.592 mg/L,其毒力高于莨菪碱和东莨菪碱。     

First isolation of calicivirus from reptiles and amphibians

Calicivirus isolations were made from 4 poikilothermic species in a zoologic collection. Viruses were recovered from 8 asymptomatic Aruba Island rattlesnakes (Crotalus unicolor; rectal swab samples) and from 8 symptomatic animals (4 Aruba Island rattlesnakes, 2 Bell's horned frogs [Ceratophrys orata], 1 rock rattlesnake [C lepidus], and 1 eyelash viper [Bothrops schlegeli] tissue samples obtained at necropsy). On the basis of cross-neutralization test results, the 16 isolates were antigenically indistinguishable and were considered to represent a unique calicivirus serotype, tentatively designated reptilian calicivirus Crotalus type 1. These isolations could not be associated causally with any specific disease entity either in naturally infected poikilotherms or in experimentally infected snakes and pigs.     

生物类黄酮的生物活性功能及其应用

生物类黄酮具有多种生物活性。本文就生物类黄酮的结构功能与种类、代谢、生物活性及其动物生产中的应用进行了阐述。     

Comparative prevalence of four enterotoxin genes among Escherichia coli isolated from swine

Presence of Escherichia coli enterotoxin genes LT (heat-labile enterotoxin), STaP (heat-stable enterotoxin a, porcine genotype), STaH (heat-stable enterotoxin a, human genotype), and STb (heat-stable enterotoxin b) among 874 swine isolates of E coli was determined, using DNA probes and the DNA colony hybridization technique. Of the 874 isolates evaluated, 45% hybridized with at least one of the enterotoxin gene probes and were designated as enterotoxigenic E coli (ETEC). Eighty-five percent of the ETEC were from pigs with enteric colibacillosis. The remaining 15% were from pigs with edema disease or various other diseases, and from healthy swine. Seventy-four percent of the ETEC hybridized with the STb probe, 52% with STaP, and 31% with LT; ETEC did not hybridize with the STaH probe. Most of the ETEC hybridized with more than one enterotoxin gene probe. Isolates that hybridized with the LT probe also hybridized with STb. The most prevalent gene combination was LT-STb. However, 35% of the ETEC from neonatal (less than or equal to 1 week old) swine with enteric colibacillosis were of the STaP-only genotype, and 33% of the ETEC from older swine with enteric colibacillosis were of the STb-only genotype.     

4种方法从葎草中制备的纳米纤维素性能

以葎草(Humulus scandens)为原料,分别采用4种方法制备了纳米纤维素,分别为硫酸水解所制得的纤维素纳米晶须(sulfuric acid-cellulose nanocrystals,S-CNC)、盐酸水解法制得的纤维素纳米晶须(hydrochloric acid-cellulose nanocrystals,H-CNC)、大功率超声法制得的纤维素纳米纤维(ultrasound-cellulose nanofibrils,U-CNF)和高速搅拌法制得的纤维素纳米纤维(stirring-cellulose nanofibrils,S-CNF),然后采用透射电子显微镜(TEM)、傅利叶红外光谱仪(FTIR)、X射线衍射仪(XRD)、热重分析仪(TGA)分别对4种纤维素的形态、化学结构、晶体结构、热稳定性能进行了表征。结果表明,硫酸水解法和盐酸水解法制备的纳米纤维素呈棒状,大功率超声法和高速搅拌法制备的纳米纤维素呈网状;S-CNC具有最高的结晶度(70.05%),而S-CNF结晶度最低(58.94%);4种纳米纤维素均保持着纤维素Ⅰ型结构;U-CNF的热稳定性最佳,开始分解温度为261.9℃,而S-CNC的热稳定性最差,初始分解温度为217.8℃。     

ISVD-2 Chytridiomycosis – an emerging and fatal infectious skin disease of amphibians

Similar to intestine and pulmonary tissue, skin is in contact with the environment and hence, requires efficient immune surveillance. The concept of skin-associated lymphoid tissue (SALT) was first introduced in 1978. The skin immune system (SIS) with its cellular and humoral components and the associated draining lymph nodes fulfills the three major functions of the innate and adaptive immune system: (1) induction of the primary immune response; (2) expression of immunity to previously encountered antigens (memory); and (3) avoidance of deleterious immune responses to nonthreatening antigens (tolerance). The cellular components of the SIS include dendritic antigen-presenting cells (Langerhans cells and dermal dendritic cells), skin-homing αβ-T lymphocytes and γδ-T lymphocytes, keratinocytes and their environment, the microvascular unit (endothelial cells of the dermal postcapillary venules), neural cells and dendritic neural processes, and the draining lymph node with its high endothelial venules. Humoral components of the SIS are defensins, complement components, immunoglobulins, cytokines, chemokines, fibrinolysin, eicosanoids and neuropeptides. Important characteristics and functions of these components and their interactions with each other will be discussed with regard to normal skin versus recruitment phase, retention phase and resolution phase associated with inflammatory conditions. The discussion will primarily focus on cutaneous dendritic antigen-presenting cells, cutaneous lymphocytes and their homing into the skin, and keratinocytes. Moreover, the importance of the microvascular unit in relation to leukocyte recruitment and migration will be discussed.     

不同动物源性维氏气单胞菌生物学特性比较研究

为深入了解维氏气单胞菌,本试验选取8株不同动物源性的维氏气单胞菌,并对其染色特性、理化特性、培养特性、耐药性、不同p H值、温度、渗透压对其生长的影响以及16S r RNA序列的相似性等生物学特性进行比较研究。结果显示,多数维氏气单胞菌在体外培养的老龄培养物中呈现多形性;理化特性大致相同;可以在TSA培养基、RS培养基、S.S.培养基、BS培养基、HE培养基上生长良好;可以在4℃、25℃~40℃、p H值6~9、氯化钠含量0%~4%中生长;对青霉素G、克林霉素、万古霉素、多粘菌素B、氨苄西林、新生霉素等表现出耐药性;经比对,不同维氏气单胞菌菌株的16S r RNA基因序列具有较高的相似性,但存在一定的差异。研究结果将为维氏气单胞菌的检验检疫、疾病预防奠定基础,同时为该菌的深入研究提供数据支持。     

植物皂苷生物活性研究进展

植物皂苷广泛分布于自然界且资源丰富,因其具有抗肿瘤、提高动物免疫力、能调节脂类代谢等多种生物活性,而具有很大的研究价值和开发前景。本研究综述了植物皂苷的结构、生物功能和在动物生产中的应用价值,旨在为进一步的开发利用提供科学参考。