Diversity and connectedness of brine shrimp viruses in global hypersaline ecosystems

Brine shrimp(Artemia)has existed on Earth for 400 million years and has major ecological importance in hypersaline ecosystems.As a crucial live food in aquaculture,brine shrimp cysts have become one of the most important aquatic products traded worldwide.However,our understanding of the biodiversity,prevalence and global connectedness of viruses in brine shrimp is still very limited.A total of 143 batches of brine shrimp(belonging to seven species)cysts were collected from six continents including 21 countries and more than 100 geographic locations worldwide during 1977–2019.In total,55 novel RNA viruses were identified,which could be assigned to 18 different viral families and related clades.Eleven viruses were dsRNA viruses,16 were+ssRNA viruses,and 28 were−ssRNA viruses.Phylogenetic analyses of the RNA-directed RNA polymerase(RdRp)showed that brine shrimp viruses were often grouped with viruses isolated from other invertebrates and fungi.Remarkably,most brine shrimp viruses were related to those from different hosts that might feed on brine shrimp or share the same ecological niche.A notable case was the novel brine shrimp noda-like virus 3,which shared 79.25%(RdRp)and 63.88%(capsid proteins)amino acid identity with covert mortality nodavirus(CMNV)that may cause losses in aquaculture.In addition,both virome composition and phylogenetic analyses revealed global connectedness in certain brine shrimp viruses,particularly among Asia and Northern America.This highlights the incredible species diversity of viruses in these ancient species and provides essential data for the prevalence of RNA viruses in the global aquaculture industry.More broadly,these findings provide novel insights into the previously unrecognized RNA virosphere in hypersaline ecosystems worldwide and demonstrate that human activity might have driven the global connectedness of brine shrimp viruses.

ISA 61 VG佐剂增强单核细胞增生李斯特氏菌灭活疫苗的保护性免疫应答

单核细胞增生李斯特氏菌(Listeria monocytogenes,Lm)是重要的人兽共患李斯特氏菌病的致病菌,疫苗免疫是预防该病原菌感染的有效手段之一。本研究研制了添加矿物油佐剂MontanideTM ISA61VG的新型灭活细菌疫苗,并对其安全性和免疫应答特性进行了研究。结果表明,ISA 61 VG佐剂疫苗具有较好的安全性;诱导小鼠产生的抗李斯特氏菌溶血素O抗体滴度以及IgG2a/IgG1比值显著高于无佐剂免疫组;在致死剂量Lm攻毒下,能对小鼠提供100%的免疫保护。因此,ISA 61VG佐剂能显著增强灭活疫苗诱导宿主产生体液免疫和细胞免疫应答的能力,从而提高灭活疫苗的保护性免疫应答作用,是预防人和动物Lm感染的潜在疫苗候选株。