DOES MATE LIMITATION IN SELF‐INCOMPATIBLE SPECIES PROMOTE THE EVOLUTION OF SELFING? THE CASE OF LEAVENWORTHIA ALABAMICA

Genetic diversity at the S‐locus controlling self‐incompatibility (SI) is often high because of negative frequency‐dependent selection. In species with highly patchy spatial distributions, genetic drift can overwhelm balancing selection and cause stochastic loss of S‐alleles. Natural selection may favor the breakdown of SI in populations with few S‐alleles because low S‐allele diversity constrains the seed production of self‐incompatible plants. We estimated S‐allele diversity, effective population sizes, and migration rates in Leavenworthia alabamica, a self‐incompatible mustard species restricted to discrete habitat patches in rocky glades. Patterns of polymorphism were investigated at the S‐locus and 15 neutral microsatellites in three large and three small populations with 100‐fold variation in glade size. Populations on larger glades maintained more S‐alleles, but all populations were estimated to harbor at least 20 S‐alleles, and mate availabilities typically exceeded 0.80, which is consistent with little mate limitation in nature. Estimates of the effective size (N_e) in each population ranged from 600 to 1600, and estimated rates of migration (m) ranged from 3 × 10⁻⁴ to nearly 1 × 10⁻³. According to theoretical models, there is limited opportunity for genetic drift to reduce S‐allele diversity in populations with these attributes. Although pollinators or resources limit seed production in small glades, limited S‐allele diversity does not appear to be a factor promoting the incipient breakdown of SI in populations of this species that were studied.     

Studies on myofibrillar protein synthesis in chicken muscular dystrophy

Myofibrillar proteins synthesized $\text{in vitro}$ by normal and dystrophic chicken muscle polysomes were purified and analyzed by SDS gel electrophoresis. No substantial difference in the synthesis of myofibrillar proteins could be detected. These observations suggest that the loss of muscle mass that is observed in muscular dystrophy is not related to a translational defect in the dystrophic polysomes.     

Novel community health worker strategy for HIV service engagement in a hyperendemic community in Rakai,Uganda: A pragmatic,cluster-randomized trial

BackgroundEffective implementation strategies are needed to increase engagement in HIV services in hyperendemic settings. We conducted a pragmatic cluster-randomized trial in a high-risk, highly mobile fishing community (HIV prevalence: approximately 38%) in Rakai, Uganda, to assess the impact of a community health worker-delivered, theory-based (situated Information, Motivation, and Behavior Skills), motivational interviewing-informed, and mobile phone application-supported counseling strategy called “Health Scouts” to promote engagement in HIV treatment and prevention services.Methods and findingsThe study community was divided into 40 contiguous, randomly allocated clusters (20 intervention clusters, n = 1,054 participants at baseline; 20 control clusters, n = 1,094 participants at baseline). From September 2015 to December 2018, the Health Scouts were deployed in intervention clusters. Community-wide, cross-sectional surveys of consenting 15 to 49-year-old residents were conducted at approximately 15 months (mid-study) and at approximately 39 months (end-study) assessing the primary programmatic outcomes of self-reported linkage to HIV care, antiretroviral therapy (ART) use, and male circumcision, and the primary biologic outcome of HIV viral suppression (<400 copies/mL). Secondary outcomes included HIV testing coverage, HIV incidence, and consistent condom use. The primary intent-to-treat analysis used log-linear binomial regression with generalized estimating equation to estimate prevalence risk ratios (PRR) in the intervention versus control arm. A total of 2,533 (45% female, mean age: 31 years) and 1,903 (46% female; mean age 32 years) residents completed the mid-study and end-study surveys, respectively. At mid-study, there were no differences in outcomes between arms. At end-study, self-reported receipt of the Health Scouts intervention was 38% in the intervention arm and 23% in the control arm, suggesting moderate intervention uptake in the intervention arm and substantial contamination in the control arm. At end-study, intention-to-treat analysis found higher HIV care coverage (PRR: 1.06, 95% CI: 1.01 to 1.10, p = 0.011) and ART coverage (PRR: 1.05, 95% CI: 1.01 to 1.10, p = 0.028) among HIV–positive participants in the intervention compared with the control arm. Male circumcision coverage among all men (PRR: 1.05, 95% CI: 0.96 to 1.14, p = 0.31) and HIV viral suppression among HIV–positive participants (PRR: 1.04, 95% CI: 0.98 to 1.12, p = 0.20) were higher in the intervention arm, but differences were not statistically significant. No differences were seen in secondary outcomes. Study limitations include reliance on self-report for programmatic outcomes and substantial contamination which may have diluted estimates of effect.ConclusionsA novel community health worker intervention improved HIV care and ART coverage in an HIV hyperendemic setting but did not clearly improve male circumcision coverage or HIV viral suppression. This community-based, implementation strategy may be a useful component in some settings for HIV epidemic control.Trial registrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02556957","term_id":"NCT02556957"}}NCT02556957.

Larry Chang and co-workers study an intervention by which community health workers aim to promote engagement in HIV treatment and prevention services in Uganda.     

Linkage relationships of peptidase-7, Pep-7, in the mouse

An electrophoretically detectable variant of peptidase-7 in Mus musculus has been found and used to locate the structural gene, Pep-7, on chromosome 5. Gene order and recombination frequencies are estimated as Pep-7 3.5±2.0 Rw 8.8±2.2 go 20.0±4.6 bf.     

Short-term variations in pelagic photosynthesis demand well-timed sampling to monitor long-term limnological changes in Lake Victoria

Oxygen concentration and water transparency at two offshore stations in Lake Victoria varied significantly during a few hours around noon. This affects comparative limnological research on changes in oxygenation after a period of perturbation. Most of the recently published papers on this subject do not account for sampling time, whereas our data show the importance of well-timed sampling programmes. This revised version was published online in July 2006 with corrections to the Cover Date.