SUMMARY The Picornaviridae represent a large family of small plus-strand RNA viruses that cause a bewildering array of important human and animal diseases. Morphogenesis is the least-understood step in the life cycle of these viruses, and this process is difficult to study because encapsidation is tightly coupled to genome translation and RNA replication. Although the basic steps of assembly have been known for some time, very few details are available about the mechanism and factors that regulate this process. Most of the information available has been derived from studies of enteroviruses, in particular poliovirus, where recent evidence has shown that, surprisingly, the specificity of encapsidation is governed by a viral protein-protein interaction that does not involve an RNA packaging signal. In this review, we make an attempt to summarize what is currently known about the following topics: (i) encapsidation intermediates, (ii) the specificity of encapsidation (iii), viral and cellular factors that are required for encapsidation, (iv) inhibitors of encapsidation, and (v) a model of enterovirus encapsidation. Finally, we compare some features of picornavirus morphogenesis with those of other plus-strand RNA viruses.

In spite of decades-long studies, the mechanism of morphogenesis of plus-stranded RNA viruses belonging to the genus Enterovirus of Picornaviridae, including poliovirus (PV), is not understood. Numerous attempts to identify an RNA encapsidation signal have failed. Genetic studies, however, have implicated a role of the non-structural protein 2CATPase in the formation of poliovirus particles. Here we report a novel mechanism in which protein-protein interaction is sufficient to explain the specificity in PV encapsidation. Making use of a novel “reporter virus”, we show that a quasi-infectious chimera consisting of the capsid precursor of C-cluster coxsackie virus 20 (C-CAV20) and the nonstructural proteins of the closely related PV translated and replicated its genome with wild type kinetics, whereas encapsidation was blocked. On blind passages, encapsidation of the chimera was rescued by a single mutation either in capsid protein VP3 of CAV20 or in 2CATPase of PV. Whereas each of the single-mutation variants expressed severe proliferation phenotypes, engineering both mutations into the chimera yielded a virus encapsidating with wild type kinetics. Biochemical analyses provided strong evidence for a direct interaction between 2CATPase and VP3 of PV and CAV20. Chimeras of other C-CAVs (CAV20/CAV21 or CAV18/CAV20) were blocked in encapsidation (no virus after blind passages) but could be rescued if the capsid and 2CATPase coding regions originated from the same virus. Our novel mechanism explains the specificity of encapsidation without apparent involvement of an RNA signal by considering that (i) genome replication is known to be stringently linked to translation, (ii) morphogenesis is known to be stringently linked to genome replication, (iii) newly synthesized 2CATPase is an essential component of the replication complex, and (iv) 2CATPase has specific affinity to capsid protein(s). These conditions lead to morphogenesis at the site where newly synthesized genomes emerge from the replication complex.

Background: Although psoriasis occurs worldwide, the prevalence varies considerably between different peoples and regions. In China, a questionnaire-based study was carried out in 1987 and the prevalence of psoriasis was found to be 0.12%. Since then, no large-scale, populationbased study has been reported. Objectives: To obtain the accurate figures for the prevalence of psoriasis in China. Methods: A population-based survey was conducted in 6 cities. The cluster sampling method was used to select communities in each city. The subjects were required to fill out self-reporting questionnaires during a face-to-face interview and also received physical examination by dermatologists. Results: 19,974 subjects were visited and 17,345 completed the questionnaires and received dermatological examination. 102 subjects (0.59%) were found to have psoriasis. After standardization, the prevalence of psoriasis was 0.47%. The prevalence of psoriasis in males and females was 0.54% and 0.44% respectively. 97.06% of the patients had psoriasis vulgaris. 28.43% of the patients reported a family history of psoriasis. 59.80% of patients experienced a negative influence on the quality of life. Conclusions: This population-based and dermatologist-confirmed study showed that the prevalence of psoriasis in China is 0.47%, which is higher than that reported in 1987.

BackgroundMechanical endometrial injury prior to IVF has been suggested as a means to increase implantation rates by improving endometrial receptivity. However, the effects of endometrial injury in proliferative vs. luteal phase have not been studied before. This study aimed to explore whether endometrial injury in the proliferative phase of the preceding cycle before in vitro fertilization/embryo transfer (IVF-ET) improves the clinical outcomes in unselected subfertile women compared with injury in luteal phase.MethodsA group of 142 patients who were good responders to hormonal stimulation were randomized into four groups: injury group (group A: endometrial injury in proliferative phase, n = 38; group B: endometrium injury in luteal phase, n = 32), and non-injury group as control (group C: non-injury in proliferative phase, n = 36; group D: non-injury in luteal phase, n = 36). Patients in injury groups underwent endometrial injury in either proliferative phase or luteal phase in the preceding cycle before IVF treatment. Clinical outcomes including implantation, pregnancy, and live birth rates were analyzed among the four groups.ResultsThe baseline characteristics of the four groups including age, body mass index, duration, type and causes of infertility were similar. There were no significant differences in implantation, clinical pregnancy or live birth rates between injury group and non-injury group. Moreover, there were also no significant differences in implantation, clinical pregnancy, or live birth rates in injury in proliferative phase compared with luteal phase.ConclusionsEndometrial injury in the cycle preceding IVF of unselected subfertile women does not increase implantation, clinical pregnancy, or live birth rates. Furthermore, there is no significant difference in clinical outcomes between endometrial injury in the proliferative phase and injury in the luteal phase.Trial registrationThis study was retrospectively registered on May 26th, 2017 (ChiCTR-IOR-17011506).

China's HIV cases are growing by more than 30% annually. Few researchers have been able to reach sex workers and examine their risk behavior patterns. Key informants in illegal prostitution connected with owners of establishments in Beijing to recruit the involvement of sex workers. A total of 69 were surveyed about their background and risk behaviors in spring, 2000 in four venues; hair salons, bathing centers, karaoke bars, and the street. The women were mostly young (in their 20s), of low socioeconomic status, and from small towns and villages. They worked about 3 to 4 days a week, averaged one to two clients per day, made the equivalent of about U.S. $135 a week, and averaged about 3 months at any one establishment. They lacked accurate knowledge of STDs/HIV, and although 61% reported consistent condom usage 93% associated usage with prevention of pregnancy and 72% perceived a low risk of HIV infection. Nearly all (98%) felt condoms were affordable, yet 37% reported they were not accessible; 74% had obtained a medical exam in the last year, but 29% were examined when sick; only 10% received prevention information during medical visits, and 55% did not know where to go for HIV testing. Based on venue, stratification among sex workers existed, impacting their risk. Sex workers are at high risk of HIV infection/transmission, especially as the virus becomes more established in Beijing. Although risk factors were consistent with those of sex workers in other countries, the variation by venue, the low perceived vulnerability to HIV, the highly illegal nature of prostitution, and high mobility of sex workers in Beijing calls for a tailored intervention approach. Prevention messages/strategies should be responsive to the differing background, knowledge,

Southern rice black-streaked dwarf virus (SRBSDV), an insect- and plant-infecting reovirus of the genus Fijivirus, induced the formation of virus-containing tubules in infected plant and insect vector cells. Expression of the nonstructural protein P7-1 of SRBSDV in insect cells by a recombinant baculovirus resulted in the formation of tubules with dimensions and appearance similar to those found in SRBSDV-infected cells. These tubules protruded from the cell surface, supporting the hypothesis that the P7-1 protein contains two putative transmembrane domains that are necessary for the formation of tubules. Furthermore, the self-interaction of SRBSDV P7-1 protein indicates that this protein has the capacity to form homodimers or oligomers to assemble the proposed helical symmetry structure of tubules. Taken together, our results indicate that SRBSDV P7-1 has the intrinsic ability of self-interaction to form tubules growing from the cell surface in the absence of other viral proteins.

Diabetes is a highly prevalent chronic disease among US adults, and its prevalence among US veterans is even higher. This study aimed to examine the prevalence of and trends in diabetes in US veterans by using data from the US National Health and Nutrition Examination Survey from 2005 through 2014. The overall prevalence of diabetes and undiagnosed diabetes was 20.5% and 3.4%, respectively, and increased from 15.5% in 2005–2006 to 20.5% in 2013–2014 (P = .04). Effective prevention and intervention approaches are needed to lower diabetes prevalence among US veterans and ultimately improve their health status.

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