Clostridium piliforme infection (Tyzzer disease) in horses: retrospective study of 25 cases and literature review

Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death; the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses; the so-called triad of lesions is not a consistent characteristic of the disease in this species.     

加工番茄粘稠度性状的配合力和遗传力分析

试验以加工番茄7个品系为试验材料,采用Griffing第2种方案配制21个杂交组合,对番茄粘稠度性状进行配合力分析和遗传力分析。结果表明,粘稠度性状一般配合力较高的亲本80、77和81,其杂交后的组合77×80、77×81的特殊配合力也最高;粘稠度性状是以基因的非加性效应为主,狭义遗传力较低,不宜早期时代进行选择。但杂种一代值具有超亲优势现象,存在杂种优势。因此,高粘稠度品种育种应以优势育种为主,辅之以杂交育种。     

黄瓜枯萎病抗性与防御系统几种酶活性关系的研究

以黄瓜6个不同抗性品系为材料,研究苗期感染枯萎病菌后,叶片组织内超氧化物歧化酶(SOD)、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸转氨酶(PAL)的活性变化。结果表明,POD,SOD,PPO活性变化曲线中存在2个酶峰,PAL活性变化曲线中存在一个单峰。抗病品系的4种酶的峰I值明显高于感病品系,表现出一致性,而且SOD和PPO酶活性的提高与抗性呈极显著正相关,POD和PAL酶活性的提高与抗性呈显著正相关。     

高粱炭疽病研究进展

高粱作为中国主要的酿造原料之一,在国民经济发展中占据重要地位。高粱炭疽病是高粱的主要病害之一,在整个生育期中均可发病,且在温暖湿润的热带和亚热带栽种地区更易发生和流行,不仅影响植株的正常生长,严重时会引起产量的大幅下降和籽粒品质的劣变。多年来,高粱病理学家和育种家对高粱炭疽病病原菌菌株分离、病害发生流行规律、发生原因、寄主抗性利用和抗炭疽病基因定位等方面进行了广泛的研究,取得了一些进展。这些研究为炭疽病的生化防控以及培育抗炭疽病品种奠定了基础。开展高粱炭疽病研究,发掘更丰富多样的优异抗性种质资源,减少农药使用,不仅可以满足中国高粱产业对天然有机高粱原料的巨大需求,还可以推动高粱生产向高产优质转变。对高粱炭疽病的分布和发病症状、炭疽病病原菌侵染机理、病害发生流行规律及流行原因、抗性资源鉴定和高粱抗炭疽病基因定位的相关研究进展进行了综合分析和论述,以期从分子水平上更好地认识高粱与炭疽病病原菌之间的相互作用,为高粱炭疽病研究提供参考。     

国家科技攻关白菜抗病育种进展

从白菜病理学研究,抗病性鉴定,抗性遗传规律和抗病机理研究,抗病新品种的选育和推广淫,抗病育种技术研究等５个方面了国家科技攻关白菜抗病育种的主要进展,并对白菜抗病育种的发展趋势和前景进行了探讨。     

Relationship between apolipoprotein E gene polymorphism and sporadic Alzheimer's disease

AIM: To evaluate the association between apolipoprotein E(apoE) gene polymorphism and sporadic Alzheimer's disease (AD). METHOD: A case-control study was undertaken detecting the polymorphism of apoE by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).RESULTS:(1)The frequencies of 3/4 genotype and 4 al ele in AD were significant ly higher than that in age-matched controls(P<0.05).(2)The frequency of G/G genotype for apoE IE1 in AD was significantly higher than that in age-mat ched control(P<0.05).(3)The apoE 4 al ele was associated with a tripling of the risk for AD compared with no 4 allele(odd ratio 2.932, 95%CI 1.379~6.226);Homozygosity of the G allele in IE1 was associated with adoubling of the risk for AD compared with the G/C and C/C genotypes(odd rat io 2.223, 95%CI 1.075~4.599).However, the IE1 G al ele is also closely associated with apoE 4.When the sample was split on the basis of apo Egenotype, the associat ion between IE1 G/G genotype and AD was no longer statistically significant.CONCLUSION: ApoE ε4 was a risk factor of AD, and the apparent association between IE1 G/G and AD is a consequence of the association between the ε4 and IE1 G/G genotype.     

长豇豆和丝瓜美洲斑潜蝇防治指标研究

连续自然接虫研究表明,长豇豆和丝瓜开花结实期美洲斑潜蝇产量损失与幼虫密度关系分别符合上列方程：Ｙ＝－０．０１１３８＋０．０００３５Ｘ（ｒ＝０．９９５３）;Ｙ＝－０．００５５２７＋０．０００６１Ｘ（ｒ＝０．９６３４）。根据当前价格和防治费用等因素,得出两种蔬菜在开花结实期的美洲斑潜蝇幼虫防治指标分别为百株８８４－１０２９头和１７７２－１９４５头。     

A reovirus disease in cultured mud crab, Scylla serrata, in southern China

A reovirus, designated mud crab reovirus (MCRV), associated with large economic losses was recently isolated from marine cultured mud crab, Scylla serrata, in southern China. The complete viral particle is 70 nm in diameter, icosahedral and non-enveloped. The virus infects connective tissue cells of the hepatopancreas, gills and intestine in mud crab and develops in the cytoplasm. Hundred per cent mortality was observed in mud crab experimentally infected by intramuscular injection, bath inoculation and oral inoculation, while cohabitation infection caused 80% mortality. The viral genome consists of 13 linear dsRNA segments, with an electrophoretic pattern 1/5/7. The results of this study suggest that the virus is highly pathogenic and can be transmitted enterically as well as via the body surface of mud crab. Although the genomic organization of this virus is different from that of the other crab reoviruses, CcRV-W2 and DpPV, all three of these reoviruses have similar electrophoresis patterns. Therefore, MCRV may be a new member of the DpPV and CcRV-W2 group.     

Alphavirus infections in salmonids--a review

The first alphavirus to be isolated from fish was recorded in 1995 with the isolation of salmon pancreas disease virus from Atlantic salmon, Salmo salar L., in Ireland. Subsequently, the closely related sleeping disease virus was isolated from rainbow trout, Oncorhynchus mykiss (Walbaum), in France. More recently Norwegian salmonid alphavirus (SAV) has been isolated from marine phase production of Atlantic salmon and rainbow trout in Norway. These three viruses are closely related and are now considered to represent three subtypes of SAV, a new member of the genus Alphavirus within the family Togaviridae. SAVs are recognized as serious pathogens of farmed Atlantic salmon and rainbow trout in Europe. This paper aims to draw together both historical and current knowledge of the diseases caused by SAVs, the viruses, their diagnosis and control, and to discuss the differential diagnosis of similar pathologies seen in cardiomyopathy syndrome and heart and skeletal muscle inflammation of Atlantic salmon.     

玉米小斑病抗性种质鉴定及生理生化分析

以200份玉米优良自交系为材料,2022-2023年夏分别进行小斑病菌的田间接种,综合两年数据共鉴定出高抗小斑病的玉米自交系3份,分别为K22、CML50和齐319;筛选到包括Mo17在内的抗性玉米自交系24份。选取K22和B73两个具有不同抗性水平的玉米自交系进行小斑病菌的室内接种。结果表明,48 h和72 h时,自交系K22叶片的病斑数、病斑面积和病斑面积比等各项指标均显著优于自交系B73,进一步验证田间鉴定的准确性。48 h或72 h时,高抗小斑病自交系K22与感病对照B73相比,5种防御酶活性增加14.32%～70.45%。