家蚕五龄后部丝腺蛋白质构成与茧层量的关系

家蚕 5龄期是后部丝腺细胞大量合成并分泌蚕丝主要成分丝素蛋白的时期 ,对这一时期后部丝腺细胞的蛋白质构成进行研究 ,有利于发现丝腺细胞分泌丝素蛋白有关的功能蛋白质 ,阐明蚕茧高产的机理。采用蛋白质双向电泳和图像分析技术 ,研究发现家蚕同一品种的不同个体 ,或同一个体不同部位的后部丝腺细胞蛋白质的构成基本一致。该结果反映了家蚕同一品种不同个体后部丝腺细胞的新陈代谢水平基本没有差异 ,家蚕品种个体间茧层量差异 ,可能是个体生长发育和后部丝腺细胞数的不同等原因造成 ,而与每一个体后部丝腺细胞的新陈代谢关系不显著。该结果也说明在目前双向电泳技术和染色技术的条件下进行家蚕后部丝腺蛋白质组研究时 ,从家蚕同一品种的任一个体、任一部位提取后部丝腺细胞的蛋白质样品 ,所得的蛋白质双向电泳结果基本相同     

A proof of concept study to assess the potential of PCR testing to detect natural Mycobacterium bovis infection in South American camelids

Background

Cases of Mycobacterium bovis infection South American camelids have been increasing in Great Britain. Current antemortem immunological tests have some limitations. Cases at post mortem examination frequently show extensive pathology. The feasibility of detecting Mycobacterium bovis DNA in clinical samples was investigated.

Findings

A sensitive extraction methodology was developed and used on nasal swabs and faeces taken post-mortem to assess the potential for a PCR test to detect Mycobacterium bovis in clinical samples. The gross pathology of the studied South American camelids was scored and a significantly greater proportion of South American camelids with more severe pathology were positive in both the nasal swab and faecal PCR tests. A combination of the nasal swab and faecal PCR tests detected 63.9% of all the South American camelids with pathology that were tested.

Conclusions

The results suggest that antemortem diagnosis of Mycobacterium bovis in South American camelids may be possible using a PCR test on clinical samples, however more work is required to determine sensitivity and specificity, and the practicalities of applying the test in the field.     

Salmonella isolated from individual reptiles and environmental samples from terraria in private households in Sweden

Background

This study investigates Salmonella spp. isolated from privately kept reptiles and from environmental samples such as bedding materials or water from the floor of the enclosures (terraria). It also compares isolation of Salmonella using Modified Semisolid Rappaport-Vassiliadis (MSRV) medium or selective enrichment in Rappaport-Vassiliadis-Soya (RVS) pepton broth. Cloacal swabs or swabs from the cloacal area were collected from 63 individual reptiles belonging to 14 households. All reptiles were from different terraria and from 62 of these, environmental samples were also collected. Sampling were done by the reptile owners according to written instructions and sent by mail immediately after sampling. All but three samples were analyzed within 24 h after collection. Colonies suspected for Salmonella were tested for agglutination and serotyped using the White-Kauffmann-Le Minor scheme. The relative sensitivity (se) and specificity (sp) for MSRV compared with RVS, and the agreement coefficient kappa (κ) were calculated.

Results

Salmonella was isolated from 50/63 (80%) terraria, either from the reptiles (31/63; 49%) or from bedding material (39/62; 63%). The most common subspecies was Salmonella enterica subspecies enterica followed by S. enterica subspecies diarizonae. In reptiles, the most common S. enterica subspecies enterica serovars were Java (n = 4) and Fluntern (n = 4), compared with the serovars Tennessee (n = 10) and Fluntern (n = 10) in the environmental samples. The exact same set of Salmonella subspecies and serovars were not isolated from the individual reptiles and the environmental samples from any of the households. Isolation using MSRV yielded more Salmonella isolates 61/113 (54%) than enrichment in RVS 57/125 (46%). The se was 97.9% (95% Confidence Interval 93.9-100), the sp 78.5% (95% CI 68.5-88.5) and the κ 0.74, indicating substantial agreement between the tests.

Conclusions

Salmonella can be expected to be present in environments where reptiles are kept. This constitutes public health risks and should be considered during handling of the reptiles and during cleaning and disposal of bedding. A combination of different culturing techniques may be used to increase the isolation rate.     

乳牛布鲁氏菌病PCR诊断试剂盒的实验室评估

对前期研制的布鲁氏菌omp25基因-PCR试剂盒的保存期、特异性和可重复性进行了测定，并应用该试剂盒对采自宁夏、甘肃、内蒙古、山西、黑龙江、新疆省（区）的98头血清凝集试验（SAT）阳性乳牛的6批98份乳样和350头SAT阴性乳牛的2批350份乳样进行了检测。检测结果显示，PCR试剂盒与SAT的阳性符合率为100％（98／98），阴性符合率为97．71％（342／350）；从SAT阴性乳牛的乳样中。用PCR试剂盒检出8份阳性，表明其敏感性高于SAT；对2株田间野毒Brgs和Br-nmg株进行了克隆与测序，二者与标准菌株序列的同源性分别为99．8％和100％。试验结果证实，本试剂盒的可重复性良好，特异性较高，-20℃下的有效保存期为5个月。     

实验猴粪便样品中沙门氏菌LAMP检测方法的建立及应用简

A loop-mediated isothermal amplification (LAMP) assay was developed for detection of Salmonlla in fecal samples of experimental monkeys. According to the specific sequences (fimY) of Salmonlla in GenBank, one set of primers was selected and the reaction condition was optimized. The results showed that the detection limit of LAMP method was 1.35×10¹ and 1.35×10³ CFU/mL in Salmonella pure culture and clinical samples,respectively,which was the same as routine PCR. The amplification could complete in one hour, and the result could be distinguished by naked eyes. There was non-specific amplification of other pathogens. These results suggested that this LAMP assay was a simple and specific method for rapid detection of Salmonlla in fecal samples.     

Bayesian modeling of animal- and herd-level prevalences

We reviewed Bayesian approaches for animal-level and herd-level prevalence estimation based on cross-sectional sampling designs and demonstrated fitting of these models using the WinBUGS software. We considered estimation of infection prevalence based on use of a single diagnostic test applied to a single herd with binomial and hypergeometric sampling. We then considered multiple herds under binomial sampling with the primary goal of estimating the prevalence distribution and the proportion of infected herds. A new model is presented that can be used to estimate the herd-level prevalence in a region, including the posterior probability that all herds are non-infected. Using this model, inferences for the distribution of prevalences, mean prevalence in the region, and predicted prevalence of herds in the region (including the predicted probability of zero prevalence) are also available. In the models presented, both animal- and herd-level prevalences are modeled as mixture distributions to allow for zero infection prevalences. (If mixture models for the prevalences were not used, prevalence estimates might be artificially inflated, especially in herds and regions with low or zero prevalence.) Finally, we considered estimation of animal-level prevalence based on pooled samples.     

一种检测奶样中布鲁氏菌抗体免疫层析方法的建立

通过制备脂多糖(LPS)并将其作为检测抗原,建立了一种检测奶样中布鲁氏菌抗体的酶联免疫层析方法。通过对处理方法和反应条件的优化,制备出敏感性高、特异性强的布鲁氏菌抗体检测试纸条。该试纸条敏感性为98.0%,抗体滴度为1:2~1:8,特异性为96.0%,且与其他常见病原无交叉反应,批内、批间重复性良好。保存期加速试验显示,该试纸条在2~30℃下可保存12个月;符合率验证显示,该方法与标准奶样的符合率达94.9%。上述结果表明,该检测方法具有敏感性高、特异性强以及方便、快捷等优点,适用于现场大批量检测,因而可应用于奶牛场布鲁氏菌病的快速诊断。     

基于数据增强的高原鼠兔目标检测

针对基于卷积神经网络的高原鼠兔目标检测模型在实际应用中缺乏训练数据的问题,提出一种前景与背景融合的数据增强方法：首先对训练集数据进行前景和背景的分离,对分离的前景作图像随机变换,对分离的背景用背景像素随机覆盖,得到前景集合和背景集合;从前景集合和背景集合中随机选取前景和背景,进行像素加融合;再从训练集中随机选取样本,将标注边界框区域采用剪切粘贴方法融合到训练图像的随机位置,得到增强数据集。采用两阶段的弱监督迁移学习训练模型,第一阶段在增强数据集上对模型预训练;第二阶段在原始训练集上微调预训练模型,得到检测模型。对自然场景下高原鼠兔目标检测的结果表明：在相同的试验条件下,基于前景与背景融合数据增强的目标检测模型的平均精度优于未数据增强、Mosaic和Cut Out数据增强的目标检测模型;基于前景、背景融合数据增强的目标检测模型的最优平均精度为78.4%,高于Mosaic的72.60%、Cutout的75.86%和Random Erasing的77.4%。     

利福昔明在人工胃/肠液和大鼠肠道菌群及组织样品中的稳定性初步分析

为初步分析利福昔明(Rifaximin)在人工胃/肠液和肠道菌群及动物组织样品中的稳定性,将利福昔明分别与空白人工胃液(pH=1.3,不含酶)、空白人工肠液(pH=6.8,不含酶)、人工胃液(pH=1.3,含胃蛋白酶)、人工肠液(pH=6.8,含胰蛋白酶)、SD大鼠(雄性)肠道菌群及不同组织样品的匀浆液等共孵育不同时间后,采用高效液相色谱法(HPLC)检测剩余利福昔明百分比的变化。结果表明:1)在空白人工胃液中,随孵育时间的增加,剩余利福昔明百分比虽有下降,但仍在90%以上;在人工胃液中孵育6 h,其剩余百分比为84.03%;而在空白人工肠液和人工肠液中孵育6 h后,其剩余百分比则分别降至81.14%和78.12%。2)利福昔明在SD大鼠肠道菌群中孵育12 h后,虽发生部分降解,但剩余百分比仍在90%以上,总体呈稳定的趋势。3)利福昔明在空白SD大鼠的胃、肝、小肠和大肠及内容物的匀浆液中分别孵育6 h后,其剩余百分比分别为92.09%、75.95%、78.24%和83.90%。综上,利福昔明在酸性条件下较稳定,而在碱性条件下,胰蛋白酶、胃蛋白酶和肠壁、肝脏代谢酶等对其稳定性的影响亦较为有限。本研究将为兽用利福昔明口服制剂的开发提供数据支持。