关键词： 新型冠状病毒   蝙蝠   稳态调节   核心素养  

摘要： 通过探讨蝙蝠为何能携带大量病毒而不发病,引导学生体会生物体内环境和生态系统的稳态与平衡、适应与调节,提高生物学学科核心素养.

关键词： 蝙蝠   冠状病毒   重组   溯源   分子流行病学  

摘要： 冠状病毒是有包膜的单股正链RNA病毒,是目前已知的RNA病毒中基因组最大的病毒,可以引起人和动物多种疾病,是非常重要的病原体。SARS和MERS爆发后,蝙蝠作为多种人兽共患病病毒的自然宿主越来越引起人们的重视,然而2019年底SARS-CoV-2在武汉的暴发流行使得蝙蝠再次成为关注的焦点。 云南省是国际知名的“动物王国”,地形多样,自然条件复杂,气候适宜,资源丰富,适合于各种野生动物的生存繁殖。其中蝙蝠物种丰富,种群庞大。自2003年以来,对云南蝙蝠体内所携带的冠状病毒一直都是研究的热点,从中发现了大量的新型蝙蝠冠状病毒,其中就包括SARS和MERS相关的冠状病毒。此外最近也在云南和周边国家发现了大量的SARS-CoV-2近亲。因此,对云南省蝙蝠所携带冠状病毒进行筛查与鉴定具有重要的意义。 本研究在2020年3月份至2021年8月份期间,在云南省4个州/市(昆明市、楚雄州、普洱市、德宏州)共采集到61只蝙蝠样本隶属4科5属11种,经筛查后确定7只蝙蝠感染或携带冠状病毒,阳性率为11.5%(7/61)。其中除了Yunnan＿YJ3c/f是发现蝙蝠肺和小肠同时存在感染,其它均只是小肠存在感染。分析基于部分Rd Rp基因核苷酸序列构建的邻接系统发育树,发现五株为α冠状病毒,两株为β冠状病毒。进一步分析发现,五株α冠状病毒其中四株为Decacovirus亚属,一株为Minunacovirus亚属;两株为β冠状病毒均为Sarbecovirus。 为了进一步解析其基因组的特征,对成功获得全长序列的病毒株进行核酸序列比较分析。其中新型Decacovirus亚属冠状病毒Yunnan/Hp JC8xc/2020和Yunnan＿Rs＿CX18c＿2020都表现出了独特的重组模式,前者发现感染不同科属蝙蝠的冠状病毒,整个S蛋白区域发生了重组,也再一次证实果蝠跨物种传播给了小蹄蝠的证据;后者从该进化支的冠状病毒序列之间的差异发现,存在着冠状病毒频繁跨科传播的可能。新型Minunacovirus亚属冠状病毒Yunnan＿Mp＿YJ3c/f＿2020,是目前为止发现的第二条Bt CoV 1B相关冠状病毒的全长,从现有的数据分析发现S蛋白区域存在着明显的差异。新型Sarbecovirus亚属冠状病毒Yunnan＿Rs＿KMC6＿2020和Yunnan＿Rp＿JCC9＿2020表现出了复杂的重组模式,前者ORF8与毒株Rf4092的序列安全一致,S蛋白区域也在发生着重组,该毒株的发现为了解SARS-CoV的起源提供了新的见解;后者的E基因和ORF10与SARS-CoV-2的序列完全一致,此外从重组模式图发现各区域与不同的SARSr-CoV-2和SARSr-CoV有较近的遗传距离。 本研究还对发现的新型蝙蝠冠状病毒与SARS-CoV-2和相关病毒的S蛋白的差异以及进化起源进行了探索。发现Yunnan＿Rp＿JCC9＿2020无论是在S蛋白和RBD序列的同源性上还是在与受体结合的必需和关键氨基上以及三维结构上面,都与SARS-CoV-2相差甚远,因此可能无法结合人ACE2,分子结合模拟也验证了上述结果。但是发现可能与果子狸和穿山甲的ACE2结合,说明可能存在跨越种间屏障,感染其他动物的潜在风险。从MCC树发现与SARS-CoV-2的TMRCA可追溯至约1938年(95%HPD:1876-1984),均早于云南发现的毒株,至少有着超过30年的序列进化。 综上所述,云南省蝙蝠物种丰富,还携带着高度多样性的冠状病毒。这会导致冠状病毒在种内传播的过程中,基因组突变和重组可能会出现跨物种传播的冠状病毒,甚至是人畜共患的冠状病毒,其中一些病毒在一定程度上促进了SARSCoV的诞生。告诫我们需要对蝙蝠及其携带的冠状病毒进行持续的监测,对保证云南省及周边地区人民和牲畜生命安全和对预防新发与再发病毒性传染病都具有十分重要的意义。

关键词： NeoCoV   PDF-2180   中东呼吸综合征病毒   受体   血管紧张素转化酶2  

摘要： 中东呼吸综合征病毒(MERS-CoV)以及一些蝙蝠冠状病毒利用二肽基肽酶-4(DPP4)作为它们的进入受体。然而,NeoCoV是目前已发现的与MERS-CoV在基因组水平上最接近的蝙蝠冠状病毒,其受体仍然未知。在本论文的研究中,我们意外地发现NeoCoV以及它的近亲PDF-2180可以高效地利用特定蝙蝠的血管紧张素转化酶2(ACE2)作为受体进入细胞,并能较弱地识别人的ACE2。这两种病毒利用它们刺突蛋白S1亚基上的C末端结构域作为受体结合域(RBD)与ACE2相互作用。冷冻电镜分析结果显示这两种病毒以一种新颖的方式结合ACE2。SARS-CoV,SARS-CoV-2以及NL63的RBD在ACE2上具有相似的足迹,与NeoCoV的RBD在ACE2上的足迹几乎没有重叠。通过结构分析,我们发现人的ACE2的338位的天门冬酰胺附近序列是限制其支持NeoCoV高效感染的种属决定因子。此外,我们还发现NeoCoV仅通过其受体结合基序(RBM)上的T510F单点突变就可以实现有效地利用人的ACE2;PDF-2180虽然在对应氨基酸上已经是苯丙氨酸,但其在RBD区域另外两处与NeoCoV的氨基酸差异使其尚不能高效地利用人的ACE2。值得一提的是,SARS-CoV-2疫苗接种者的血清以及特异性识别MERS-CoV的纳米抗体都不能有效地阻断含有NeoCoV和PDF-2180刺突蛋白的假病毒入侵。我们的研究首次报道了一类重要的MERS-CoV相关的蝙蝠冠状病毒可以利用ACE2作为受体。这一发现使我们更加深入地了解了冠状病毒的感染入侵机制,并对防范与应对潜在的人畜共患病毒威胁具有重要指导意义。

关键词： sickness behavior   immune response   social behavior   foraging   chiroptera  

摘要： Along with its many advantages, social roosting imposes a major risk of pathogen transmission. How social animals reduce this risk is poorly documented. We used lipopolysaccharide challenge to imitate bacterial infection in both a captive and a free-living colony of an extremely social, long-lived mammal-the Egyptian fruit bat. We monitored behavioral and physiological responses using an arsenal of methods, including onboard GPS to track foraging, acceleration sensors to monitor movement, infrared video to record social behavior, and blood samples to measure immune markers. Sick-like (immune-challenged) bats exhibited an increased immune response, as well as classic illness symptoms, including fever, weight loss, anorexia, and lethargy. Notably, the bats also exhibited behaviors that would reduce pathogen transfer. They perched alone and appeared to voluntarily isolate themselves from the group by leaving the social cluster, which is extremely atypical for this species. The sick-like individuals in the open colony ceased foraging outdoors for at least two nights, thus reducing transmission to neighboring colonies. Together, these sickness behaviors demonstrate a strong, integrative immune response that promotes recovery of infected individuals while reducing pathogen transmission inside and outside the roost, including spillover events to other species, such as humans.

关键词： Rabies virus   Cranial cavity lavage   Bats   RTCIT   RT-PCR  

摘要： The rabies virus (RABV) has been isolated in several bats species in the world, and among them, hematophagous, frugivorous and insectivorous species. Bats found in Brazil are small, which can lead to situations in which there are limitations in the collection of the central nervous system (CNS) and the amount of material may be insufficient to carry out laboratory diagnostic techniques for rabies. The objective of this work was to evaluate an alternative sample collection for the diagnosis of rabies in bats. A total of 92 bat samples, 82 positives and 10 negatives were selected. The cranial cavity was scraped with the aid of sterile tips and a virus diluent was added to create a suspension. All samples were submitted to Rabies Tissue Culture Infection Test (RTCIT) and reverse transcription polymerase chain reaction (RT-PCR). The diagnostic sensitivity and specificity of the RTCIT and RTPCR using the cranial cavity lavage were calculated in comparison with the results of the laboratory routine (DFAT and RTCIT) performed with the CNS (considered gold standard). The results of the RTCIT show that the cranial cavity lavage is not an adequate sample for viral isolation, since the diagnostic sensitivity was low (37.8 %) when compared with the tests with the CNS. However, the RT-PCR of the cranial cavity lavage may be a tool to assist in the diagnosis, since it presented a sensitivity of 76.8 %. The results of this study suggest that cranial cavity lavage is an interesting alternative to enable the diagnosis of rabies in bats and increases the possibility of diagnosis contributing to rabies surveillance and control.

关键词： adaptive immunity   gene family evolution   inflammatory pathway   innate immunity   metabolism   viral tolerance  

摘要： Comprising more than 1,400 species, bats possess adaptations unique among mammals including powered flight, unexpected longevity, and extraordinary immunity. Some of the molecular mechanisms underlying these unique adaptations includes DNA repair, metabolism and immunity. However, analyses have been limited to a few divergent lineages, reducing the scope of inferences on gene family evolution across the Order Chiroptera. We conducted an exhaustive comparative genomic study of 37 bat species, one generated in this study, encompassing a large number of lineages, with a particular emphasis on multi-gene family evolution across immune and metabolic genes. In agreement with previous analyses, we found lineage-specific expansions of the APOBEC3 and MHC-I gene families, and loss of the proinflammatory PYHIN gene family. We inferred more than 1,000 gene losses unique to bats, including genes involved in the regulation of inflammasome pathways such as epithelial defence receptors, the natural killer gene complex and the interferon-gamma induced pathway. Gene set enrichment analyses revealed genes lost in bats are involved in defence response against pathogen-associated molecular patterns and damage-associated molecular patterns. Gene family evolution and selection analyses indicate bats have evolved fundamental functional differences compared to other mammals in both innate and adaptive immune system, with the potential to enhance antiviral immune response while dampening inflammatory signalling. In addition, metabolic genes have experienced repeated expansions related to convergent shifts to plant-based diets. Our analyses support the hypothesis that, in tandem with flight, ancestral bats had evolved a unique set of immune adaptations whose functional implications remain to be explored.

关键词： Bats   Echolocation   Hair cells   ISL1   Noise protection  

摘要： Exposure to intense noise can damage cochlear hair cells, leading to hearing loss in mammals. To avoid this constraint, most mammals have evolved in relatively quiet environments. Echolocating bats, however, are naturally exposed to continuous intense sounds from their own and neighboring sonar emissions for maintaining sonar directionality and range. Here, we propose the presence of intense noise resistance in cochlear hair cells of echolocating bats against noise-induced hearing loss (NIHL). To test this hypothesis, we performed noise exposure experiments for laboratory mice, one nonecholocating bat species, and five echolocating bat species. Contrary to nonecholocating fruit bats and mice, the hearing and the cochlear hair cells of echolocating bats remained unimpaired after continuous intense noise exposure. The comparative analyses of cochleae transcriptomic data showed that several genes protecting cochlear hair cells from intense sounds were overexpressed in echolocating bats. Particularly, the experimental examinations revealed that ISL1 overexpression significantly improved the survival of cochlear hair cells. Our findings support the existence of protective effects in cochlear hair cells of echolocating bats against intense noises, which provides new insight into understanding the relationship between cochlear hair cells and intense noises, and preventing or ameliorating NIHL in mammals.

关键词： bats   epidemiology   Flavivirus   infection   viruses  

摘要： Infections with viruses of the Flavivirus genus were explored in 22 bats (Artibeus jamaicensis) from Merida, Yucatan, Mexico. The detection of the viral genus was performed by RT-PCR, and infections with dengue (DENV 1-4), West Nile (WNV) and Zika (ZIKV) viruses were subsequently explored. Sequences from positive products were analysed using the BLAST algorithm to determine identity. In 7 (31.8%) and 2 (9.1%) bats, WNV and ZIKV were identified, respectively. The bioinformatic analysis showed 98%-100% coverage and identity for both viruses. Molecular evidence of WNV and ZIKV natural infection in bats from Yucatan, Mexico, is presented.