Cultivation of mosquito cell lines in serum-free media and their effects on dengue virus replication

Summary Seven mosquito cell lines from five species (Aedes aegypti, Ae. albopictus, Ae. pseudoscutellaris, Culex tarsalis, andToxorhynchites amboinensis) were adapted to three kinds of serum-free media (SEM), which were composed of equal volumes of tryptose phosphate broth and of either Leibovitz (L15) medium, Eagle’s minimum essential medium, or Medium 199 with Hanks’ salts. Population growth rates of the cells cultivated in the SMFs were generally slower than those of original cell cultures maintained in conventional media containing bovine sera. A karyological study showed a significant shift to heteroploidy in two of the four cell lines examined. Four SMF-adapted sublines were compared with parental cultures for replication of dengue viruses.Ae. aegypti RML-12,Ae. albopictus C6/36,Ae. pseudoscutellaris AP-61, andTx. amboinensis TRA-171 demonstrated different levels of alteration in virus replication ranging from lower titers (as inAe. albopictus C6/36) to comparable or higher titers (as inAe. aegypti RML-12) when they were simultaneously inoculated with four dengue serotypes. Use of trade names and commercial sources is for identification only and does not constitute endorsement by the Public Health Service or by the U.S. Department of Health and Human Services.     

不同来源的肾综合征出血热病毒对Vero细胞的致病变作用

前文报道,肾综合征出血热病毒76-118株能使Vero细胞产生病变。本文报道76-118株和另11株不同来源的肾综合征出血热病毒(H537、A9、H5、R178、HB55、R22、Z10,沟3、L99、A16和J10)对Vero细胞的致病变作用(CPE )。其中除沟3株外,大部分毒株在感染Vero细胞后的第一代即可见明显的CPE。CPE的特点与76-118株相似,主要是感染细胞粘聚、融合,形成网状结构。CPE能被特异性抗HFRS病毒血清和型特异性单克隆抗体所中和抑制,但不能被特异性抗呼肠孤病毒Ⅲ型免疫血清所中和抑制。HFRS病毒对Vero细胞的致病变作用,对进一步研究HFRS病毒的某些生物学特性及实验方法等均有重要意义。     

饮用水水源与自来水中病毒和指示细菌存在水平的比较研究

自来水中人肠道病毒的存在已引起人们极大的关切和忧虑。本文报道了武汉东湖水和以东湖为水源的自来水中病毒和指示细菌的存在水平。水源水经过预加氯消毒、絮凝沉淀、砂滤和最后加氯消毒处理而成的自来水中细菌总数检测范围是41—500/升,总大肠菌是2—13/升、粪大肠菌为0—4/升、大肠菌噬菌体是0—13.6PFU/升,平均2.48PFU/升,肠道病毒为0—78PFU/升,平均为6.7PFU/升。水源水经制水工艺处理去除指示细菌、大肠菌噬菌体和肠道病毒的效率分别为97.95—99.99％,90.63％和53.18％。这种结果说明自来水制水工艺能有效地降低指示细菌,大肠菌噬菌体,而去除肠道病毒效率较低,揭示肠道病毒对环境压专的耐受性明显地比指示细菌强。     

The ultrastructural indicators of aquatic ecosystem health

Analyses by transmission electron microscopy (TEM) of the smallest organisms in surface waters can be used to assess ecosystem health; the evidence for this statement is reviewed and recommendations are made for optimal use of TEM technology in providing such assessments. Those groups of small organisms currently being considered as indicators of ecosystem health (viruses, bacteria, autotrophic picoplankton, and autotrophic nanoplankton) are reviewed briefly as subjects for monitoring by TEM. New information on direct counting by TEM of viral femtoplankton indicates that viruses can be present in numbers 10³ to 10⁷ times greater than previously estimated by the traditional counts of plaque-forming units using various host bacteria. Such concentrations indicate that virus infections may exert ecological control over planktonic microbes. Ultrastructural research on prokaryotic picoplankton suggests that TEM analyses of cells in ultra-thin sections can be used to speciate the picoplankton and to diagnose them for cytological modifications related to environmental stress. Considering their great importance, episodically, to primary productivity and to modulating the speciation of higher levels in the food web, such picoplankton ultrastructural analyses could be pursued with profit as a diagnostic tool. For decades, the ultrastructure of some eukaryotic nanoplankton has been known to vary in specific ways to specific stresses in laboratory experiments. An extension of these structure-function correlations is potentially a useful tool to provide indicators of ecosystem health. The barriers to progress in such research are now understood and can be overcome.     

Identification of two nuclear polyhedrosis viruses from the cabbage moth, Mamestra brassicae (Lepidoptera: Noctuidae)

Two nuclear polyhedrosis viruses from the cabbage moth Mamestra brassicae found in two geographical areas in Europe have been characterized and compared. These two virus isolates have similar biological activities and have the same host range. The two M. brassicae nuclear polyhedrosis viruses can be distinguished by restriction endonuclease analysis of their DNA. They appear to be distinct but related virus strains.     

A global invasion by the thrip,Frankliniella occidentalis: Current virus vector status and its management

Western flower thrip, Frankliniella occidentalis (Pergande), is among the most economically important agricultural pests globally, attacking a wide range of vegetable and horticultural crops. In addition to causing extensive crop damage, the species is notorious for vectoring destructive plant viruses, mainly belonging to the genera Orthotospovirus, Ilarvirus, Alphacarmovirus and Machlomovirus. Once infected by orthotospoviruses, thrips can remain virulent throughout their lifespan and continue transmitting viruses to host plants when and wherever they feed. These irruptive viral outbreaks in crops will permanently disrupt functional integrated pest management systems, and typically require a remedial treatment involving insecticides, contributing to further development of insecticide resistance. To mitigate against this continuing cycle, the most effective management is early and comprehensive surveillance of the pest species and recognition of plant viruses in the field. This review provides information on the pest status of F. occidentalis, discusses the current global status of the viruses vectored by this thrip species, examines the mechanisms involved in transmitting virus‐induced diseases by thrips, and reviews different management strategies, highlighting the potential management tactics developed for various cropping systems. The early surveillance and the utilization of potential methods for control of both F. occidentalis and viruses are proposed.     

Comparative review of respiratory diseases caused by coronaviruses and influenza A viruses during epidemic season

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to sweep the world, causing infection of millions and death of hundreds of thousands. The respiratory disease that it caused, COVID-19 (stands for coronavirus disease in 2019), has similar clinical symptoms with other two CoV diseases, severe acute respiratory syndrome and Middle East respiratory syndrome (SARS and MERS), of which causative viruses are SARS-CoV and MERS-CoV, respectively. These three CoVs resulting diseases also share many clinical symptoms with other respiratory diseases caused by influenza A viruses (IAVs). Since both CoVs and IAVs are general pathogens responsible for seasonal cold, in the next few months, during the changing of seasons, clinicians and public heath may have to distinguish COVID-19 pneumonia from other kinds of viral pneumonia. This is a discussion and comparison of the virus structures, transmission characteristics, clinical symptoms, diagnosis, pathological changes, treatment and prevention of the two kinds of viruses, CoVs and IAVs. It hopes to provide information for practitioners in the medical field during the epidemic season.