Inhibition of Cdc42 activity extends lifespan and decreases circulating inflammatory cytokines in aged female C57BL/6 mice

Cdc42 is a small RhoGTPase regulating multiple functions in eukaryotic cells. The activity of Cdc42 is significantly elevated in several tissues of aged mice, while the Cdc42 gain‐of‐activity mouse model presents with a premature aging‐like phenotype and with decreased lifespan. These data suggest a causal connection between elevated activity of Cdc42, aging, and reduced lifespan. Here, we demonstrate that systemic treatment of aged (75‐week‐old) female C57BL/6 mice with a Cdc42 activity‐specific inhibitor (CASIN) for 4 consecutive days significantly extends average and maximum lifespan. Moreover, aged CASIN‐treated animals displayed a youthful level of the aging‐associated cytokines IL‐1β, IL‐1α, and INFγ in serum and a significantly younger epigenetic clock as based on DNA methylation levels in blood cells. Overall, our data show that systemic administration of CASIN to reduce Cdc42 activity in aged mice extends murine lifespan.     

Identifying key biodiversity areas as marine conservation priorities in the greater Caribbean

Increasing rates of Anthropocene biodiversity extinctions suggest a possible sixth mass extinction event. Conservation planners are seeking effective ways to protect species, hotspots of biodiversity, and dynamic ecosystems to reduce and eventually eliminate the degradation and loss of diversity at the scale of genes, species, and ecosystems. While well-established, adequately enforced protected areas (PAs) increase the likelihood of preserving species and habitats, traditional placement methods are frequently inadequate in protecting biodiversity most at risk. Consequently, the Key Biodiversity Area (KBA) Partnership developed a set of science-based criteria and thresholds that iteratively identify sites where biodiversity is most in need of protection. KBA methodology has been rarely applied in the marine realm, where data are often extremely limited. We tested the feasibility of KBA population metrics in the Greater Caribbean marine region using occurrence and population data and threat statuses for 1669 marine vertebrates. These data identified areas where site-specific conservation measures can effectively protect biodiversity. Using KBA criteria pertaining to threatened and irreplaceable biodiversity, we identified 90 geographically unique potential KBAs, 34 outside and 56 within existing PAs. These provide starting points for local conservation managers to verify that KBA thresholds are met and to delineate site boundaries. Significant data gaps, such as population sizes, life history characteristics, and extent of habitats, prevent the full application of the KBA criteria to data-poor marine species. Increasing the rate and scope of marine sampling programs and digital availability of occurrence datasets will improve identification and delineation of KBAs in the marine environment.

     

Prevalence and risk factors of schistosomiasis among primary school children in four selected regions of The Gambia

BackgroundThe Gambia initiated a control programme for schistosomiasis in 2015. In light of this, recent and comprehensive data on schistosomiasis is required to effectively guide the control programme. This study aimed to evaluate the prevalence and associated risk factors of schistosomiasis among primary school children in The Gambia.MethodsWe utilised data from a previous study conducted in 2015 in 4 regions of The Gambia: North Bank Region (NBR), Lower River Region (LRR), Central River Region (CRR) and Upper River Region (URR). In the parent study, ten schools were selected randomly from each region. Urine and stool samples collected from 25 boys and 25 girls (7–14 years) in each school were examined for urinary schistosomiasis (Schistosoma haematobium infection) and intestinal schistosomiasis (Schistosoma mansoni infection) using urine filtration, dipstick and Kato-Katz methods.Principal findingsUrinary schistosomiasis had an overall prevalence of 10.2% while intestinal schistosomiasis had a prevalence of 0.3% among the sampled school children. Prevalence of urinary schistosomiasis was significantly different among regions (χ 2 = 279.958, df = 3, p < 0.001), with CRR (27.6%) being the most endemic region, followed by URR (12.0%), then LRR (0.6%), and NBR (0.0%). Prevalence of intestinal schistosomiasis was also significantly variable among regions, with 4 of the 5 positive cases detected in CRR and 1 case in URR. Every school sampled in CRR had at least one student infected with S. haematobium, 50% of schools in URR had S. haematobium infection, and just one school in LRR had S. haematobium infection. While S. haematobium infection was significantly higher in boys (χ 2 = 4.440, df = 1, p = 0.035), no significant difference in infection rate was observed among age groups (χ 2 = 0.882, df = 2, p = 0.643). Two of the 5 students infected with S. mansoni were boys and 3 were girls. Four of these 5 students were in the 10–12 years age group and 1 was in the 7–9 years age group. Macrohaematuria and microhaematuria were found to be statistically associated with presence of S. haematobium eggs in urine. Being a male was a risk factor of S. haematobium infection. Bathing, playing and swimming in water bodies were found to pose less risk for S. haematobium infection, indicating that the true water contact behaviour of children was possibly underrepresented.ConclusionThe findings of this study provide invaluable information on the prevalence of schistosomiasis in The Gambia. This was useful for the schistosomiasis control efforts of the country, as it guided mass drug administration campaigns in eligible districts in the study area. More studies on S. mansoni and its intermediate snail hosts are required to establish its true status in The Gambia. As children sometimes tend to provide responses that potentially please the research or their teacher, data collection frameworks and approaches that ensure true responses in studies involving children should be devised and used.     

The birds and the seeds: opportunistic avian nectarivores enhance reproduction in an endemic montane aloe

Opportunistic bird pollination has become more evident in studies that confirm distinct differences in floral adaptations that attract opportunistic, rather than specialist, bird pollinators. Pollination syndrome studies investigating the effectiveness of different pollinator guilds on reproduction seldom do so by measuring seed viability. We studied pollination in Aloe peglerae, a high altitude endemic succulent of the Magaliesberg mountain range, previously thought to be largely sunbird (specialist) pollinated. Using field observation and pollinator exclusion treatments, i.e. (i) open to all visitors, (ii) bird excluded, and (iii) all visitors excluded, we established that birds contributed significantly more to fruit (2.3–5.6 times) and seed (1.3–1.4 times) set than insect or self-pollination, respectively. Overall, pollination by opportunistic avian nectarivores amplified seed production per aloe ~7 and 10 times compared to insects and self-pollination, respectively. One of three opportunistic nectarivores, the Cape Rock-Thrush (Monticola rupestris), played a significant role in pollination, contributing ~60 % of all probes at inflorescences. The difference in reproductive output between insect visited and visitor excluded flowers was not significant and suggests possible self-pollination in A. peglerae which is particularly unusual in Aloe species. Breeding system experiments would help clarify this. In assessing the effectiveness of pollinator guild on seed viability, we found no differences in percentage seed viability, seed germination or seedling emergence between exclusion treatments. Seed viability and germination were low and variable; however, ~19 % seedling emergence was observed across the treatments. Practically, the net effect of bird pollination may result in 8–12 times more potential seedlings compared to insect and self-pollination respectively. These findings highlight the importance of pollination by opportunistic avian nectarivores in Aloe.     

Systematic biases in DNA copy number originate from isolation procedures

Background

The ability to accurately detect DNA copy number variation in both a sensitive and quantitative manner is important in many research areas. However, genome-wide DNA copy number analyses are complicated by variations in detection signal.

Results

While GC content has been used to correct for this, here we show that coverage biases are tissue-specific and independent of the detection method as demonstrated by next-generation sequencing and array CGH. Moreover, we show that DNA isolation stringency affects the degree of equimolar coverage and that the observed biases coincide with chromatin characteristics like gene expression, genomic isochores, and replication timing.

Conclusion

These results indicate that chromatin organization is a main determinant for differential DNA retrieval. These findings are highly relevant for germline and somatic DNA copy number variation analyses.