Effects of ribosomes on the kinetics of Qβ replication

Bacteriophage Qβ utilizes some host cell translation factors during replication. Previously, we constructed a kinetic model that explains replication of long RNA molecules by Qβ replicase. Here, we expanded the previous kinetic model to include the effects of ribosome concentration on RNA replication. The expanded model quantitatively explained single- and double-strand formation kinetics during replication with various ribosome concentrations for two artificial long RNAs. This expanded model and the knowledge obtained in this study provide useful frameworks to understand the precise replication mechanism of Qβ replicase with ribosomes and to design amplifiable RNA genomes in translation-coupling systems.     

The effect of sevoflurane on developing A/J strain mouse embryos using a whole-embryo culture system—the incidence of cleft lip in culture embryos

A/J strain mice have a high spontaneous incidence of cleft lip (ICL) and/or palate. The primary palate-related effects of sevoflurane on developing A/J strain mouse embryos (embryos) were studied using a whole-embryo culture (WEC) system. This system could separate the direct effects of sevoflurane from those that are maternally mediated. A total of 205 10.5-d embryos were cultured for 24 h in either a control group (control gas: 95% O₂ and 5% CO₂) or sevoflurane-administered groups (1/4, 1/2, and 1 minimum alveolar concentration (MAC) with control gas) for 8 h. After 16 h, 11.5-d culture embryos were examined in terms of crown-rump length, number of somites, and protein content. Crown-rump length in the 1 MAC was significantly shorter than in the control group (p?<?0.05). Protein content in the 1/2 MAC (p?<?0.05) and 1 MAC (p?<?0.001) was significantly lower than in the control group. The ICL showed no significant differences between each group. (The ICL rose with an increase in the sevoflurane concentration, but this was not significant). The positive findings in this study indicate that a WEC system is useful for studying the mechanisms of ICL (teratogenicity) associated with sevoflurane.     

Domestic dog demographics and estimates of canine vaccination coverage in a rural area of Zambia for the elimination of rabies

BackgroundAn estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries.Methodology/Principal findingsA cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01–0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8–51.6%. This low coverage was principally attributed to the owners’ lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8–76.2%.Conclusions/SignificanceThis paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.