南海石斑鱼苗种肠道微孢子虫病病原的鉴定

研究通过组织病理分析、超微结构观察以及分子特征分析对石斑鱼(Epinephelus spp.)苗种肠道微孢子虫病病原进行了鉴定。其为一肠孢虫属新种, 命名为石斑鱼肠孢虫(Enterospora epinepheli sp. n.), 专性寄生于细胞核内, 发育过程与肠孢虫属模式种黄道蟹肠孢虫(Enterospora canceri)一致。早期单核裂殖体通过一层简单的电子薄膜与宿主细胞核质隔离。随后, 单核裂殖体发育形成多核裂殖原质团。此时, 细胞核出现明显肥大, 有的甚至被裂殖子胀破。裂殖原质团进一步发育形成多核产孢体, 并开始出现许多高电子密度的囊泡状结构。这些与极丝及锚状盘有关的囊泡状结构聚集在藕核周围, 并组装形成微孢子虫特征性结构(挤出装置)前体。随后, 产孢体原生质团通过连续分裂形成一个个孢子母细胞。孢子母细胞与细胞核直接接触, 并直接发育形成成熟孢子。成熟孢子椭圆形, 孢子长(1.56±0.31) μm (1.07—1.96 μm), 宽(1.08±0.98) μm (0.93—1.28 μm)。 孢壁分为3层, 外壁电子密度高, 厚(15.51±0.95) nm (9.87—26.18 nm), 内壁为电子透明层, 较外层更厚(81.13±2.71) nm (57.16—110.81 nm), 最里面为孢质膜。极丝为同型极丝, 共5—6圈, 分2排排列。组织病理学分析发现该微孢子虫寄生于肠道上皮杯状细胞核内, 肠壁脱落的内容物中也发现大量的微孢子虫。序列比对发现该种与之前报道的石斑鱼肠道微孢子虫待定种(Microsporidium sp.)序列基本一致, 与其他相似性较高的种类的遗传距离在0.162—0.225。系统发育关系分析显示肠胞虫科的种类明显分为两支, 石斑鱼肠孢虫和肠孢虫属其他种类及毕氏肠胞虫聚为一个独立分支, 但不与该分枝中任何种类形成姊妹支。     

水貂阿留申病抗体检测技术研究及应用进展

水貂阿留申病严重危害毛皮动物产业发展,其病毒中和抗体不能提供保护能力,相反可造成水貂持续性感染,迄今尚无特异的防治方法。因此世界各国主要通过抗体检测技术筛选并淘汰阳性水貂以达到阿留申病的净化清除。本文介绍了阿留申抗体检测的经典技术,常规检测技术对流免疫电泳及一些有潜在应用价值的新兴技术,并对其发展趋势做了展望。     

侵袭性念珠菌病的抗原抗体检测进展

念珠菌是常见的一种条件致病菌,可在皮肤、黏膜等部位与宿主共存.当正常寄居部位的微生态环境失调或机体免疫机能低下时,易侵入体液及器官,引起念珠菌病.近年来,侵袭性真菌感染的发病率及死亡率呈明显上升的趋势,最新的流行病学调查结果[1]显示,美国念珠菌病医院感染率为0.28‰ ～0.96‰,欧洲为0.2‰ ～0.38‰.拉丁美洲念珠菌院感率为1.2‰ ～ 5.5‰,若伴长期的中性粒细胞缺乏或发热,医院感染率可升至7％[1].     

核桃枯枝病新病原及生物学特性

【目的】鉴定四川省广元市剑阁县核桃枯枝病的病原,为该病害的防治奠定基础。【方法】随机采集不同发病阶段的枝干样品30份,采用常规组织分离法分离纯化核桃枯枝病病原菌,用柯赫氏法则对菌株进行致病性验证,结合形态学特征和分子生物学方法对病原菌进行鉴定,采用菌落生长法进行生物学特性研究。【结果】共分离得到180个菌株。致病性测定结果表明核桃枯枝病的病原菌为拟茎点霉Phompsis capsici,这是首次关于Phompsis capsici导致核桃枯枝病在我国发生和研究的报道。在PDA平板上该病原菌菌丝为白色,能产生椭圆形和线形两种分生孢子。病菌菌丝生长以PDA培养基为最适。菌丝能有效利用多种碳、氮源,在供试的9种碳、氮源中,适宜生长的碳源为蔗糖和果糖,氮源为钼氨酸和苯丙氨酸。最适生长温度为25°C,最适pH为6.0-7.0。黑暗条件下菌丝生长最快。【结论】Phompsis capsici最易从伤口侵入致病。     

东方蜜蜂微孢子虫的基因结构优化及新基因鉴定

东方蜜蜂微孢子虫Nosema ceranae是一种寄生于蜜蜂中肠上皮细胞的单细胞真菌,对蜜蜂的健康危害严重,给世界各国的养蜂业造成较大损失。本研究基于前期获得的N.ceranae孢子的转录组数据对其已注释基因进行结构优化,并对未注释基因进行预测和分析。通过将测序得到的clean reads比对参考基因组和转录本重构,共对10个N.ceranae的已注释基因的5'端或3'端进行了延长。利用Cuffcompare软件将重构转录本与参考基因组进行比对,共鉴定出27个新基因,随机挑选9个新基因进行RT-PCR验证,均能扩增出符合预期的目的片段,表明预测出的新基因真实存在。有6个新基因能够注释到GO数据库和6个基因注释到KEGG数据库。进一步分析结果显示上述新基因注释到细胞等10个GO条目上,它们可能在N.ceranae的生命活动中具有重要功能。研究结果为N.ceranae的基因结构和功能注释信息的完善提供了有益补充,也为新基因的功能研究打下了基础。     

蝗虫微孢子虫病在草原蝗虫优势种种群及空间的分布

在采用蝗虫微孢子虫Nosema locustae防治过的草场中进行抽样调查,研究了草原蝗虫优势种类、混合种群平均密度与蝗虫微孢子虫疾病分布之关系,以及该疾病的空间分布。在防治后的当年,蝗虫微孢子虫疾病的感染率随着混合种群平均密度及靶标蝗虫亚洲小车蝗Oedaleus asiaticus的感病率的下降而降低。但是,次靶标蝗虫如宽须蚁蝗Myrmeleotettixpalpalis(一种中后期发生的种类)其感病率呈上升趋势,表明该疾病可在不同发生期种类蝗虫之间进行有效地传播。病蝗虫在防治后第7d其空间分布呈随机分布(Poisson),第28d 则是聚集分布,第40d时也呈聚集分布。于1993年、1994年对1988年(样区Ⅱ)、1989 年(样区Ⅲ)采用微孢子虫防治过的草场进行抽样调查。结果表明,在二个样区中,二年混合种群平均虫口密度与混合种群的平均感病率呈正相关(相关系数分别为r=0.289, r=0.479)。蝗虫微孢子虫病在主要优势种,如亚洲小车蝗、宽须蚁蝗、白边痂蝗Bryode maluctuosumluctuosum、皱膝蝗Angaracris /I>spp.、毛足棒角蝗Dasyhippus barbipes均有分布。二个样区中的混合蝗虫种群的平均感病率在1994年显著低于1993年。混合蝗虫种群的种类组成也有所变化,与1993年相比,1994年宽须蚁蝗及白边痂蝗的比例上升较大,而亚洲小车蝗的比例下降。经过5—7年的扩散,蝗虫微孢子虫病至少可扩散距防治区1 000m,其扩散方向可能与风及地势等有关。     

比格犬埃立克体病实验模型及治疗研究

目的研究了比格犬埃立克体病实验模型及盐酸强力酶素对犬埃立克体病的疗效。方法用犬埃立克体病病犬血白细胞静脉注射比格犬,对其临床症状、病原学、血液生理生化指标变化、病理学变化进行了观察,并应用盐酸多西环素进行疗效试验。结果与结论成功建立了比格犬埃立克体病实验模型,并证实了盐酸多西环素对犬埃立克体病的疗效是确定的。     

外阴阴道念珠菌病的病原检测及体外药敏试验

目的了解STD门诊患者外阴阴道念珠菌病的菌种分布及对常用抗真菌药物的敏感状况,为临床治疗提供参考。方法取STD门诊疑似念珠菌感染患者的阴道分泌物标本,用沙氏琼脂培养基分离纯化菌株,然后用ATB ID 32C酵母菌鉴定系统和ATB Fungus3药敏系统进行菌种鉴定与药物敏感试验。结果950份标本中检出306株念珠菌,占32.21%,其中白色念珠菌226株,阳性率为73.86%;光滑念珠菌37株,阳性率为12.09%;热带念珠菌24株,阳性率为7.84%;近平滑念珠菌13株,占4.25%。药敏结果显示：念珠菌对5-氟胞嘧啶（5-FC）;两性霉素B（AMB）,伏立康唑（VRC）耐药率〈6%;近平滑念珠菌对5种抗真菌药物均敏感;白色念珠菌对氟康唑（FCZ）、伊曲康唑（ICZ）耐药率依次：9.29%、11.06%,光滑念珠菌药耐药率依次为37.84%,67.57%,热带念珠菌药耐药率依次为8.33%、12.5%。结论STD门诊患者阴道念珠菌检出率明显高于普通妇科门诊患者,检出菌种仍以白色念珠菌为主,但光滑念珠菌和热带念珠菌生殖道感染有明显上升趋势;念珠菌对两性霉素B、5-氟胞嘧啶敏感性较高,对唑类药物有耐药菌株。因此,念珠菌鉴定和药敏监测是非常必要的,临床医生应根据药敏结果合理使用抗真菌药物。     

蚕种微粒子病检测中存在的问题及对策探究

蚕业的生产安全问题至关重要,本文首先从蚕种生产的角度介绍了我国蚕种微粒子病的产生原因,并揭示了在当前微粒子病检测中存在的问题,提出了相应的解决对策,以期提高微粒子病抽检结果的准确性和真实性。     

新烟碱类杀虫剂对鸟类的影响及检测方法综述

新烟碱类农药是一类广泛应用于农田生态系统的内吸型杀虫剂,具有杀虫广谱、持效期长和作用机制独特等特点。作为激动剂,它们选择性作用于昆虫烟碱型乙酰胆碱酯受体(nAChRs)。以往普遍认为,新烟碱类杀虫剂仅对靶标性昆虫杀灭性强,对鸟类等非靶标性生物毒性较低。但最近越来越多的研究表明,新烟碱类杀虫剂的暴露会对非靶标性鸟类造成负面影响。本文综述了新烟碱类杀虫剂的检测方法及其对鸟类的影响。国外较多的研究关注新烟碱类杀虫剂对鸟类种群数量、繁殖生态和迁徙能力的影响,但国内研究很少关注此类问题。针对我国现有研究的不足,提出了今后关于新烟碱类杀虫剂对鸟类影响研究方向,以期为科学评估新烟碱类杀虫剂对鸟类的暴露风险提供依据。     

Immunoglobulin Levels in Non-Aborted and Aborted Fetuses from Danish Herds of Cattle

The applicability of serological tests in the diagnosis of intrauterine infections in Danish cattle was investigated. Fetuses from slaughter animals, experimentally infected and spontaneously aborted fetuses, premature and stillborn calves, were subjected to necropsy and histological studies, and to microbiological and serological examinations. The latter comprised rocket immunoelectrophoresis and radial immunodiffusion. In sera of the fetuses from slaughter animals, immunoglobulins were either not detectable or only present in very small quantities, whereas sera of fetuses and calves with pathological changes and/or verified infection contained considerable amounts of IgM and IgG. IgA was also detected in the latter group. The results corroborate the diagnostic importance of immunoglobulin determination in aborted fetuses and stillborn calves.     

Assessing the Welfare of Dairy Cattle

This article attempts to determine the effects of environment (captive or wild) and a simple form of environmental enrichment on the behavior and physiology of a nonhuman animal. Specifically, analyses first compared behavioral budgets and stereotypic behavior of captive coyotes (Canis latrans) in kennels and pens to their counterparts in the wild. Second, experiments examined the effect of a simple form of environmental enrichment for captive coyotes (food-filled bones) on behavioral budgets, stereotypies, and corticosteroid levels. Overall, behavioral budgets of captive coyotes in both kennels and pens were similar to those observed in the wild, but coyotes in captivity exhibited significantly more stereotypic behavior. Intermittently providing a bone generally lowered resting and increased foraging behaviors but did not significantly reduce stereotypic behavior or alter corticosteroid levels. Thus, coyote behavior in captivity can be similar to that exhibited in the wild; in addition, although enrichment can affect proportions of elicited behaviors, abnormal behaviors and corticosteroid levels may require more than a simple form of environmental enrichment for their reduction.     

Assessing the Welfare of Dairy Cattle

This article suggests that health problems represent some of the main threats to the welfare of dairy cattle. Although disagreement often arises about what constitutes the main welfare problems, there is broad agreement that welfare is reduced by health problems. In recent decades, a marked increase has occurred in the incidence of various production diseases in dairy cattle of which lameness is the most prevalent. This article summarizes the evidence showing that lameness is affected by the genetics of the animal and by housing. High levels of production do not necessarily lead to increased lameness, although genetic correlations between levels of production and the incidence of lameness suggest that continued high selection for milk production will likely exacerbate the problem. Denying access to pasture may increase the incidence of some forms of lameness. Both the design of the stall and the type of walking surface can have a large effect on the incidence of hoof problems for the nonhuman animal kept in free-stall housing. Finally, management and nutritional factors can have a large effect, often obscuring the influence of housing. The behavior of the cow, particularly time spent lying or standing, can influence the likelihood of lameness.     

Complete Genome Sequence of Brucella melitensis Biovar 3 Strain NI,Isolated from an Aborted Bovine Fetus

From an aborted bovine fetus in China, a bacterial strain named NI was isolated and identified as Brucella melitensis by a PCR assay. Strain NI was further characterized as B. melitensis biovar 3 using biochemical assays. Here we report the complete genome sequence of strain NI.     

奶牛和肉牛6个STR基因座遗传多态性研究

利用PCR技术和复合电泳银染技术检测奶牛和肉牛BM2113、BM1862、BMc701、BM2934、TGLA122、BM720等6个STR基因座的多态性分布,并计算该6个基因座的基因频率(P_i)、个体鉴别力(DP)、杂合度(H)、多态信息含量(PIC)、和非父排除概率(PE)。结果显示:6个STR基因座的基因型分布符合Hardy-Weinberg平衡,奶牛中6个STR基因座中BM2113基因座的DP、H和PIC最高,TGLA122基因座的PE最高。6个STR基因座的累积个体鉴别力(CDP)为0.99997,累积非父排除能力(CPE)为0.98827。肉牛中6个STR基因座中BM1862基因座的DP、H、PIC、PE都是最高,6个STR基因座的累积个体鉴别力(CDP)为0.99999,累积非父排除能力(CPE)为0.99578。结果表明,6个STR基因座可用于牛的遗传连锁分析、个体识别和亲子鉴定等研究领域。     

Molecular comparison of the dense granule proteins GRA6 and GRA7 of Neospora hughesi and Neospora caninum

Neospora hughesi is a recently described apicomplexan parasite that has been associated with several cases of equine protozoal myeloencephalitis. The biology of this new parasite is just beginning to be defined. Towards this understanding, we report important differences between the nucleotide and deduced amino acid sequences of the dense granule proteins GRA6 and GRA7 of N. hughesi and Neospora caninum. This information can be used to differentiate the two species and contribute to further understanding of the prevalence and biology of N. hughesi. The newly defined proteins of N. hughesi are referred to as NhGRA6 and NhGRA7 in keeping with the protocol for naming homologous proteins of the Apicomplexa. Genes of the two dense granule proteins of N. hughesi (isolate Nh-A1) and four different isolates of N. caninum were isolated via PCR and their DNA sequences were determined. Computer analysis indicated that the two gene sequences were identical among all four N. caninum isolates. However, the gene for NhGRA6 was found to be 96 nucleotides longer at the 3' end than that of NcGRA6, resulting in a protein product that is 32 amino acids larger than NcGRA6. Two tandem repeat sequences were identified at the 3' end of the NhGRA6 gene. These repeat sequences contributed to the lengthening of the carboxy terminus of NhGRA6 in comparison with that of NcGRA6. The larger size of NhGRA6 was further confirmed by Western blot analysis in which NcGRA6 monospecific antibodies recognised a protein of approximately 42 kDa in N. hughesi whole tachyzoite preparation but a protein of 37 kDa in N. caninum whole tachyzoite preparation. Analysis of GRA7 gene sequences indicated a 6 and 14.8% difference at nucleotide and amino acid sequence level, respectively, between NcGRA7 and NhGRA7. Despite the same number of residues in the deduced amino acid sequences of all the GRA7 proteins, Western blot analysis indicated a difference in the migration pattern of NhGRA7 in comparison with NcGRA7. Results of our study indicate that diagnostic tests based on differences in dense granule sequences and antigenicity may have potential to differentiate between N. hughesi and N. caninum. Such diagnostic tests would be valuable tools to aid in our understanding of the epidemiology of these parasites. Additionally, dense granule proteins are immunogenic and they may have potential as use in recombinant vaccines against neosporosis.     

Characterization and Relatedness of Marine Vibrios Pathogenic to Fish: Physiology, Serology, and Epidemiology

Cultural characteristics and serological relationships of pathogenic marine vibrios isolated from fish in the Pacific Northwest were studied. These organisms were compared with cultures of Vibrio anguillarum, a known fish pathogen. On the basis of morphological and cultural characteristics, the Pacific Northwest strains of Vibrio were found to be closely related to V. anguillarum. Serological analyses of thermostable antigens served to distinguish three serotypes among the vibrios. Serotype 1 was composed of organisms isolated from Northwest salmonids; serotype 2 of strains of V. anguillarum from European waters; and serotype 3 of organisms isolated from Pacific herring. The epidemiology of vibrio disease among populations of fish in the Pacific Northwest is discussed.