Temporal constraints on the potential role of fry odors as cues of past reproductive success for spawning lake trout

Deciding where to reproduce is a major challenge for most animals. Many select habitats based upon cues of successful reproduction by conspecifics, such as the presence of offspring from past reproductive events. For example, some fishes select spawning habitat following odors released by juveniles whose rearing habitat overlaps with spawning habitat. However, juveniles may emigrate before adults begin to search for spawning habitat; hence, the efficacy of juvenile cues could be constrained by degradation or dissipation rates. In lake trout (Salvelinus namaycush), odors deposited by the previous year's offspring have been hypothesized to guide adults to spawning reefs. However, in most extant populations, lake trout fry emigrate from spawning reefs during the spring and adults spawn during the fall. Therefore, we postulated that the role of fry odors in guiding habitat selection might be constrained by the time between fry emigration and adult spawning. Time course chemical, physiological, and behavioral assays indicated that the odors deposited by fry likely degrade or dissipate before adults select spawning habitats. Furthermore, fry feces did not attract wild lake trout to constructed spawning reefs in Lake Huron. Taken together, our results indicate fry odors are unlikely to act as cues for lake trout searching for spawning reefs in populations whose juveniles emigrate before the spawning season, and underscore the importance of environmental constraints on social cues.     

Reticulon 3 interacts with NS4B of the hepatitis C virus and negatively regulates viral replication by disrupting NS4B self‐interaction

The non‐structural protein 4B (NS4B) of the hepatitis C virus (HCV) is an endoplasmic reticulum (ER) membrane protein comprising two consecutive amphipathic α‐helical domains (AH1 and AH2). Its self‐oligomerization via the AH2 domain is required for the formation of the membranous web that is necessary for viral replication. Previously, we reported that the host‐encoded ER‐associated reticulon 3 (RTN3) protein is involved in the formation of the replication‐associated membranes of (+)RNA enteroviruses during viral replication. In this study, we demonstrated that the second transmembrane region of RTN3 competed for, and bound to, the AH2 domain of NS4B, thus abolishing NS4B self‐interaction and leading to the downregulation of viral replication. This interaction was mediated by two crucial residues, lysine 52 and tyrosine 63, of AH2, and was regulated by the AH1 domain. The silencing of RTN3 in Huh7 and AVA5 cells harbouring an HCV replicon enhanced the replication of HCV, which was counteracted by the overexpression of recombinant RTN3. The synthesis of viral RNA was also increased in siRNA‐transfected human primary hepatocytes infected with HCV derived from cell culture. Our results demonstrated that RTN3 acted as a restriction factor to limit the replication of HCV.     

Seroprevalence of Merkel Cell Polyomavirus in the General Rural Population of Anyang,China

Background

Despite the probably causal link between Merkel cell polyomavirus (MCPyV) infection and Merkel cell carcinoma (MCC), a rare but aggressive skin malignancy, little is known about the seroepidemiology of MCPyV among healthy adults in China.

Methods

Serum antibodies against MCPyV were evaluated by multiplex serology in a population-based study of 5548 adults (including 1587 heterosexual couples) aged 25–65 years who were enrolled from rural Anyang, China in 2007–2009. Univariate and multivariate logistic regression analyses were performed to assess the risk factors for the seropositivity of MCPyV.

Results

The seroprevalence for MCPyV was 61.0%. MCPyV seropositivity was significantly higher in males than in females (64.5% vs. 57.7%, P<0.001), and for both genders, showed a trend of increase with age (Male: P _trend<0.001; Female: P _trend<0.001). Furthermore, among antibody positives, antibody levels of MCPyV increased with advancing age (P _trend = 0.017). MCPyV seropositivity of one spouse was significantly associated with that of the other partner (Adjusted OR = 1.32, 95% CI: 1.07–1.62). However, there was no association between sexual behaviors and the seropositivity of MCPyV.

Conclusions

High seroprevalence of MCPyV was observed in healthy Chinese individuals. Serological evidence suggests that nonsexual horizontal spread of MCPyV can occur among family members, and further research in this regard is needed.     

An electrochemical stripping metalloimmunoassay based on silver-enhanced gold nanoparticle label

A novel, sensitive electrochemical immunoassay has been developed based on the precipitation of silver on colloidal gold labels which, after silver metal dissolution in an acidic solution, was indirectly determined by anodic stripping voltammetry (ASV) at a glassy-carbon electrode. The method was evaluated for a noncompetitive heterogeneous immunoassay of an immunoglobulin G (IgG) as a model. The influence of relevant experimental variables, including the reaction time of antigen with antibody, the dilution ratio of the colloidal gold-labeled antibody and the parameters of the anodic stripping operation, upon the peak current was examined and optimized. The anodic stripping peak current depended linearly on the IgG concentration over the range of 1.66 ng ml(-1) to 27.25 microg ml(-1) in a logarithmic plot. A detection limit as low as 1 ng ml(-1) (i.e., 6 x 10(-12) M) human IgG was achieved, which is competitive with colorimetric enzyme linked immuno-sorbent assay (ELISA) or with immunoassays based on fluorescent europium chelate labels. The high performance of the method is attributed to the sensitive ASV determination of silver (I) at a glassy-carbon electrode (detection limit of 5 x 10(-9) M) and to the catalytic precipitation of a large number of silver on the colloidal gold-labeled antibody.     

水生哺乳动物信标跟踪记录技术及其应用

水生哺乳动物(主要是鲸类和鳍脚类)分布范围广、活动范围大、行为复杂,且在水下活动时间长,常规的目视观察受时间和空间限制,通常只能获取有限的信。信标跟踪记录(Bio-logging)具有可跟随移动和自主操作的特征,能在很大程度上突破时间和空间限制,实时获取动物及其栖息环境信息。水生哺乳动物的信标跟踪记录始于20世纪60年代1,2,40年来,无论是记录技术,还是应用研究,都有了很大发展。2003年在日本东京国立极地研究所召开的“信标跟踪记录科学国际学术讨论会(International Symposium on Bio-loggingScience)”,收到来自法、美、英、日、澳、德、意、加、南非和中国共152名与会代表的104篇论文。这些论文主要介绍信标跟踪记录技术及其应用的现状和未来趋势。会议以不同研究对象分专题进行交流,共分为鲸类、鳍脚类、类、爬行类、鱼类和其他类6个专题,其中鸟类专题论文最多,其次是鱼类专题。有关水生哺乳动物的研究论文共22篇,除了4篇介绍记录技术外,其他论文主要介绍信标跟踪记录的应用研究,包括潜水行为、捕食策略、能量代谢、栖息地标识和发声策略研究。本文是近年来水生哺乳动物信标跟踪记录研究领域相关论文的综述,除介绍水生哺乳动物信标跟踪记录技术及其应用研究现状外,还对其不足之处和可能的发展趋势进行了讨论。此外,还重点介绍了我国珍稀动物长江江豚(Neophocaena phocaenoides as iaeorientalis)信标跟踪研究的一些进展。       

A comparison of in vitro anticancerous activity and mechanism of ethanolic extracts from different Ganoderma genus

Five ethanolic extracts from the mycelia of Ganoderma lucidum, G. tsugae, G. oerstedii, G. subamboinense, and G. resinaceum were respectively studied on their anticancerous activities against leukemic HL-60 cell line in vitro. Results showed that all five extracts potently inhibited HL-60 proliferation. The extract from G. lucidum mycelia exerted the highest activity. Annexin V/PI bivariate flow cytometric analysis further revealed that the five extracts significantly induced early apoptosis in HL-60 cells. The results illustrate that not only G. lucidum but also other Ganoderma species can inhibit cancer cells, and their mechanisms are related to induction of apoptosis. __________ Translated from Journal of Shanghai Normal University (Natural Sciences), 2005, 34(2): 77–81 [译自: 上海师范大学学报 (自然科学版), 2005, 34(2): 77–81]     

Development of a biosensor assessing SARS-CoV-2 main protease proteolytic activity in living cells for antiviral drugs screening

Highlights:
The biosensor reported in our study can monitor SARS-CoV-2 M^pro activity in living cells instead of in vitro solutions.
The biosensor reported in our study is sensitive and easy to operate.
It is suitable for high-throughput screening.
It has the potential to be used in small animal models.