Development of a sensitive detection system for Cryptosporidium in environmental samples

The identification of Cryptosporidium species and genotypes is necessary to determine sources of infection in outbreaks and the risk factors associated with their transmission. Few studies have applied isolation methods to field samples because of difficulties with detection of oocysts in environmental samples, particularly in soil and manure. The objective of this study was to develop an easy to use method which can be applied to field samples to rapidly detect the presence of Cryptosporidium parasites and identify their species. The assay included an oocyst recovery method combined with spin column DNA extraction, followed by PCR-hybridization for detection and a real-time PCR-melting curve analysis for species assignment. An internal positive control (IPC) was developed to determine the presence of PCR inhibitory substances. Two oocyst recovery methods, sodium chloride and sucrose flotation techniques were compared. Two commercial DNA extraction kits were performed using feces, soil and water samples each inoculated with different concentration of Cryptosporidium oocysts. Subsequently, methods were used to test field samples. The sucrose flotation method provided the greatest analytical sensitivity detecting as few as 10 oocysts. The PCR-hybridization detection limit was 10 oocysts for feces and soil, and less than 10 oocysts for water samples. IPC was positive for all inoculated and field samples indicating 0% PCR inhibition. Cryptosporidium species DNA samples were detected with the real-time PCR and were differentiated by the melting curve analysis. The results of this study demonstrate the potential of the assay system for rapid detection of Cryptosporidium parasites in environmental samples.     

JIW-SD100A漏电保护器常见的故障原因与处理方法

本文仅列举了JIW—SD100A型低压漏电保护器本身常见故障原因与处理方法,不包括线路对保护器的影响.对以下故障的处理方法无特殊说明的,均为不带电处理.     

DBL-5型漏电电流动作保护器常见的故障与处理

DBL-5型漏电电流动作保护器在我市已推广使用4年,具有质量可靠、性能稳定、故障率低等特点,深受广大农村用户的欢迎.现向读者朋友介绍其常见故障(包括外部)的查找与处理方法.     

浅谈彩电和录像机的制式

彩电、录像机（包括放像机）是家庭中的主要电器，了解它们的制式，对正确的使用具有非常重要的意义。广泛采用并具有兼容黑白电视信号的彩色电视接收机及录像机的制式有三种：NTSC制式、PAL制式和SECAM制式。我国的彩电、录像机制式一般采用PAL制；美国、日本等国家彩电用的是     

Pathological and microbiological studies on pneumonic lungs from Danish calves

During 1 year, the association between microbiological and pathological findings in 72 lungs from calves submitted to the Danish Veterinary Laboratory for diagnostic purposes was studied. All cases were evaluated pathologically and bacteriologically, whereas only 68 cases were examined for the presence of bovine respiratory syncytial virus (BRSV), parainfluenza-3 virus (PI-3 virus) and bovine coronavirus, 62 cases for bovine viral diarrhoea virus (BVD), 45 cases for bovine adenovirus and 51 cases for mycoplasmas. Based on histopathological examination, the cases were diagnosed as fibrinous and/or necrotizing bronchopneumonia, suppurative bronchopneumonia, embolic pneumonia and others. The diagnoses were based on the dominating and most severe lesions in each lung. Haemophilus somnus, Pasteurella multocida, Actinomyces pyogenes, P. haemolytica and BRSV were the most commonly found bacterial and viral lung pathogens, respectively. Pasteurella spp. and H. somnus were often associated with the more severe fibrinonecrotizing type of bronchopneumonia, whereas BRSV was primarily detected in cases of suppurative bronchopneumonia. Mycoplasma bovis was isolated from one case only, whereas M. dispar, M. bovirhinis and Ureaplasma diversum were present, often concomitantly, in the majority of cases. Aspergillus fumigatus was isolated from one case.     

Translation Inhibition of Capped and Uncapped Viral RNAs Mediated by Ribosome-Inactivating Proteins

ABSTRACT Ribosome-inactivating proteins (RIPs) are N-glycosidases that remove specific purine residues from the sarcin/ricin (S/R) loop of the large rRNA and arrest protein synthesis at the translocation step. In addition to their enzymatic activity, RIPs have been reputed to be potent antiviral agents against many plant, animal, and human viruses. We recently showed that pokeweed antiviral protein (PAP), an RIP from pokeweed, inhibits translation in cell extracts by binding to the cap structure of eukaryotic mRNA and viral RNAs and depurinating these RNAs at multiple sites downstream of the cap structure. In this study, we examined the activity of three different RIPs against capped and uncapped viral RNAs. PAP, Mirabilis expansa RIP (ME1), and the Saponaria officinalis RIP (saporin) depurinated the capped Tobacco mosaic virus and Brome mosaic virus RNAs, but did not depurinate the uncapped luciferase RNA, indicating that other type I RIPs besides PAP can distinguish between capped and uncapped RNAs. We did not detect depurination of Alfalfa mosaic virus (AMV) RNAs at multiple sites by PAP or ME1. Because AMV RNAs are capped, these results indicate that recognition of the cap structure alone is not sufficient for depurination of the RNA at multiple sites throughout its sequence. Furthermore, PAP did not cause detectable depurination of uncapped RNAs from Tomato bushy stunt virus (TBSV), Satellite panicum mosaic virus (SPMV), and uncapped RNA containing poliovirus internal ribosome entry site (IRES). However, in vitro translation experiments showed that PAP inhibited translation of AMV, TBSV, SPMV RNAs, and poliovirus IRES dependent translation. These results demonstrate that PAP does not depurinate every capped RNA and that PAP can inhibit translation of uncapped viral RNAs in vitro without causing detectable depurination at multiple sites. Thus, the cap structure is not the only determinant for inhibition of translation by PAP.     

Evaluation of melatonin receptor 1a as a candidate gene influencing reproduction in an autumn-lambing sheep flock

The effect of the melatonin receptor 1a (MTNR1A) gene on fertility and litter size in autumn lambing was studied with 373 ewes from a population of sheep selected for 10 yr for fertility in May and June matings. Animals were from a composite line of 50% Dorset, 25% Rambouillet, and 25% Finnsheep. Two restriction fragment length polymorphisms were present in the population, with allelic frequencies of 0.42 and 0.58 for an MnII polymorphism (alleles M and m, respectively) and of 0.34 and 0.66 for an RsaI polymorphism (alleles R and r, respectively). Genotypic frequencies for the polymorphisms were not independent, suggesting an association between them in foundation animals. Effects of MTNR1A genotype on fertility and litter size were evaluated using mixed linear model or REML procedures, but were not significant for matings involving ewes of all ages. However, in adult ewes (3 yr old and older), fertility of ewes of genotype mm was 10.0 (mixed model; P < 0.09) to 11.2% (REML; P = 0.03) less than that of other ewes. Genotypic effects associated with MTNR1A in adult ewes accounted for 23.8% of the estimated total additive genetic variance in fertility. Litter size was not significantly associated with MTNR1A genotype; adult ewes of genotype mm had approximately 0.11 fewer lambs per ewe lambing than ewes of other genotypes. Fertility in autumn lambing is lowly heritable, expressed only in females, and manifested relatively late in life and only in some management systems. Access to genetic markers would thus be advantageous in selection programs.     

Dermatophytosis in three colony-born spotted hyenas

An adult female hyena and her two 4-month-old cubs were found to have multifocal areas of alopecia and dermatitis. Dermatophyte culture of hair and skin samples collected from the lesions yielded Trichophyton mentagrophytes. None of 10 other animals in the colony that were tested were found to have dermatophytes. Lesions were treated twice, at 3-week intervals, with thorough cleansing with chlorhexidine scrub followed by topical application of antifungal agents. Lesions resolved, and dermatophyte culture of samples collected 6 weeks after the initiation of treatment did not yield growth.