Spotlight on avian coronaviruses

ABSTRACT

Coronaviruses (CoVs) mainly cause enteric and/or respiratory signs. Mammalian CoVs including COVID-19 (now officially named SARS-CoV-2) belong to either the Alphacoronavirus or Betacoronavirus genera. In birds, the majority of the known CoVs belong to the Gammacoronavirus genus, whilst a small number are classified as Deltacoronaviruses. Gammacoronaviruses continue to be reported in an increasing number of avian species, generally by detection of viral RNA. Apart from infectious bronchitis virus in chickens, the only avian species in which CoV has been definitively associated with disease are the turkey, pheasant and guinea fowl. Whilst there is strong evidence for recombination between gammacoronaviruses of different avian species, and between betacoronaviruses in different mammals, evidence of recombination between coronaviruses of different genera is lacking. Furthermore, the recombination of an alpha or betacoronavirus with a gammacoronavirus is extremely unlikely. For recombination to happen, the two viruses would need to be present in the same cell of the same animal at the same time, a highly unlikely scenario as they cannot replicate in the same host!     

Effects of a feed additive blend on broilers challenged with heat stress

ABSTRACT

We evaluated a blend of medium-chain fatty acids (MCFA), organic acids, and a polyphenol antioxidant on gut integrity. Eighty Ross Broilers were exposed to 20–22°C (control – normothermic) or to 35–39.5°C (heat stress) for eight hours a day for a period of 1 or 5 days. Birds were fed a standard diet, or a diet supplemented with the test blend. Thereafter, birds were euthanized, and intestinal sections were excised for morphological, morphometric and gene expression analyses. Blood samples were collected for glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GSH-Px) activity and trolox equivalent antioxidant capacity (TEAC) determination. Heart and liver tissues were used to quantify the expression of heat shock proteins 60 and 70 (HSP60 and HSP70, respectively) and inhibitor of kappa light chain gene enhancer in B cells alpha (IKBA). The jejunum was the most sensitive intestinal section, where heat stress modulated the expression of HSP70, of the inflammatory markers IKBA, interleukin 8 (IL-8), interferon gamma (IFNγ), and toll-like receptor 4 (TLR4). Moreover, expression of tight junctions (CLDN1, ZO1 and ZO2) and nutrient transporters (PEPT1 and EAAT3) was modulated especially in the jejunum. In conclusion, the feed additive blend protected intestines during heat stress from the decrease in villus height and crypt depth, and from the increase in villus width. Especially in the jejunum, heat stress played an important role by modulating oxidative stress and inflammation, impairing gut integrity and nutrient transport, and such deleterious effects were alleviated by the feed additive blend.

RESEARCH HIGHLIGHTS

• Jejunum is the most sensitive intestinal segment during heat stress.

• Heat stress affects the expression of tight junctions and nutrient transporters.

• Feed management helps to alleviate the disturbances caused by heat stress.

• A blend of MCFA, organic acids and a polyphenol protects broilers under heat stress.

     

活细胞内单分子视踪检测研究进展

对细胞生物学与分子生物学中有关分子事件和相互作用的认识,大部分都是在非活体条件下、忽略分子事件全过程所得到的研究结果,并且这些研究结果是基于被研究的所有单分子在相同的环境以相同的方式运动这个不真实的假设.随着量子点(QDs)等新的荧光物质和抗体模拟物等小分子抗体连接后制备成的新型探针的出现,以及转导外源性荧光探针进入活细胞内的各种方法的发展,再加上优良的荧光成像系统和快速灵敏的荧光采集系统在生命科学中的应用,使得视踪活细胞单个生物分子的轨迹、运动及多种单分子的相互作用成为现实.单分子水平的视踪研究为细胞生物学和分子生物学的研究打开了新的篇章.概述了目前活细胞内单分子视踪技术的研究进展并评价了其发展前景.     

布氏显微镜活血分析: 细胞流变学研究的新方法

布氏显微镜活血分析：细胞流变学研究的新方法骆秉铨＊黄荣国＊陈兴新＊细胞流变学是研究血细胞流动变形的科学，在方法学上发展了一些比较成熟的方法，但多不能直接动态观察细胞水平的真实改变，有待完善和创新。我们采用布氏多功能显微镜的活血分析法［１］，在高放大倍...     

OHSS高风险全胚冷冻后FET时机对妊娠结局的影响

目的探讨OHSS高风险患者全胚冷冻后冻融胚胎移植(FET)的时机。方法回顾性分析2014年6月至2018年12月于西北妇女儿童医院生殖中心接受IVF/ICSI-ET治疗,因OHSS高风险而全胚冷冻的患者共2060例。根据取卵日距第1次FET日的时间长短分为两组:时间间隔≤40 d为立即FET组,共196例;时间间隔>40 d为延迟FET组,共1864例。对比分析两组间的妊娠结局及新生儿体重。结果两组间女方年龄、BMI、不孕类型及不孕年限、Gn总量、优质胚胎数、扳机日雌激素水平等基线资料的差异均无统计学意义(P>0.05);两组间胚胎种植率、临床妊娠率、流产率、活产率、早产率、单胎及双胎新生儿出生体重、异常出生体重发生率等指标差异均无统计学意义(P>0.05);Logistic回归分析显示,延迟FET对活产率、胚胎种植率、临床妊娠率、流产率无显著性影响(P>0.05)。调整影响妊娠结局的混杂因素,包括女方年龄、女方BMI、移植胚胎个数及移植胚胎类型后,延迟FET对活产率[OR=1.104,95%CI(0.813,1.502),P=0.536]、胚胎种植率[OR=0.907,95%CI(0.641,1.283),P=0.569]、临床妊娠率[OR=0.892,95%CI(0.634,1.275),P=0.529]、流产率[OR=0.924,95%CI(0.575,1.496),P=0.750]的影响仍不显著。两组新生儿出生体重及异常体重新生儿的发生率间差异无统计学意义(P>0.05)。结论因OHSS高风险而全胚冷冻患者,取卵术后首次月经来潮即可开始准备内膜进行FET,延迟FET并不能改善妊娠结局。     

Determinants of biosecurity practices in French duck farms after a H5N8 Highly Pathogenic Avian Influenza epidemic: The effect of farmer knowledge,attitudes and personality traits

Biosecurity is crucial for infectious disease prevention, more importantly in the absence of vaccination. The need for improving the implementation of biosecurity practices was highlighted in French duck farms following the 2016–2017 H5N8 Highly Pathogenic Avian Influenza (HPAI) epidemic. Farmers have multiple reasons for not implementing biosecurity practices: external (time, money) and internal (socio‐psychological). The purpose of this study was to determine how sets of socio‐psychological factors (i.e. knowledge on biosecurity and avian influenza transmission, attitudes, personality traits, social background) affect the adoption of on‐farm biosecurity practices. Biosecurity practices and socio‐psychological determinants were assessed during 127 duck farm visits, in South West France, using both questionnaires and on‐farm observations. Factorial analysis of mixed data (FAMD) and hierarchical clustering analysis (HCA) identified three groups of farmers with different socio‐psychological profiles: the first group was characterized by minimal knowledge, negative attitudes towards biosecurity, little social pressure and a low level of conscientiousness. The second group was characterized by more extensive experience in poultry production, higher stress and social pressure. The third group was characterized by less experience in poultry production, better knowledge and positive attitudes towards biosecurity, increased self‐confidence and orientation towards action. The first group had a significantly lower adoption of biosecurity measures than the two other groups. A better understanding of the factors involved in farmers' decision‐making could improve the efficiency of interventions aiming at improving and maintaining the level of on‐farm biosecurity in the duck industry.     

Construction and evaluation of a pertactin-deficient live attenuated pertussis vaccine candidate BPZE1 derivative

Pertussis, mainly caused by Bordetella pertussis, is a severe respiratory disease that can be fatal, especially in young infants. Vaccines, massively implemented since the middle of the last century, have substantially reduced the pertussis incidence, but have not been able to fully control the disease. One of the shortcomings of current pertussis vaccines is their inability to prevent infection by and transmission of B. pertussis, in contrast to immunity following natural infection. We have developed the live attenuated nasal vaccine BPZE1 and have shown that it prevents both disease and B. pertussis infection in preclinical models. This vaccine is now in clinical development. However, the initial clinical studies have suggested that vaccine take is hampered by pre-existing antibodies to pertactin. Here, we have constructed a pertactin-deficient BPZE1 derivative called BPZE1P in order to overcome this limitation. BPZE1P colonized the murine respiratory tract as efficiently as BPZE1 and induced antibodies at levels similar to those elicited by BPZE1. In the presence of pre-existing antibodies induced by acellular pertussis vaccination, BPZE1P colonized the mouse respiratory tract more efficiently than BPZE1. Both vaccines protected equally well the murine lungs and noses from challenge with laboratory and clinical strains of B. pertussis, including pertactin-deficient strains, against which current acellular pertussis vaccines are less efficient. BPZE1P may thus be an interesting alternative to BPZE1 to overcome vaccine take limitations due to pre-existing antibodies to pertactin.     

胰高血糖素对胆道梗阻大鼠肝脏葡萄糖和酮体合成的作用

目的观察胰高血糖素对胆道梗阻大鼠肝脏葡萄糖和酮体合成作用的影响。方法大鼠胆道结扎４８小时后,用胶原酶灌流后分离肝细胞,加入胰高血糖素温育,用分光光度计按标准酶学方法检测葡萄糖、乙酰乙酸和三羟基丁酸。结果在基础或最大刺激条件下,加胰高血糖素结扎组、假手术组葡萄糖异生均明显大于未加胰高血糖素组（Ｐ＜０．０５）,加胰高血糖素对结扎组和假手术组的酮体异生无促进作用。结论胰高血糖素对胆道梗阻４８小时大鼠肝细胞的糖异生存在有意义的刺激作用,对酮体异生则无刺激作用     

流行性乙型脑炎减毒活疫苗大面积接种后安全性和流行病学效果的5年观察

目的 考核乙脑减毒活疫苗大面积接种后的安全性和降低乙脑发病率,在乙脑高发区安徽省蒙城和涡阳县进行为期５年（１９９２￣１９９６年）的人群观察。方法 观察对象１￣６岁儿童。１岁初免１针,２岁加强１针。结果 通过５年连续观察共接种乙脑活疫苗３３５９４１人。 表明：①疫苗对小龄儿童接种后近期和５年内均未出现不良反应,表明疫苗是安全的。②当地乙脑平均总发病率有显著性下降,从接种观察前１９８７￣１９９１年的１     

禽类养殖场人员禽流感病毒抗体水平调查

目的 调查珠海地区养殖场人员中禽流感H5和H9二种亚型血清中抗体水平，以了解上述2种禽类甲型流感病毒亚型以往的接触感染情况，为防治人问禽流感提供科学依据。方法 珠海地区养殖场人员血清277份，正常出入境人员血清270份，通过血凝抑制试验HI实验进行抗体检测。结果 养殖场人群中H9亚型抗体阳性率为2．17％，同时发现有1份血清H5抗体阳性，H5抗体阳性率为0．36％。而正常出入境人群H9亚型抗体阳性率为2．96％；未见H5亚型抗体的存在。结论 H9亚型在养殖场人群和出入境人群中的存在隐性感染，但感染率不高；养殖场人群H5亚型抗体的存在也应值得注意。