The short-term effects of surface soil disturbance on soil bacterial community structure at an experimental site near Scott Base, Antarctica

Humans are visiting Antarctica in increasing numbers, and the ecological effect of rapid soil habitat alteration due to human-induced physical disturbance is not well understood. An experimental soil disturbance trial was set up near Scott Base on Ross Island, to investigate the immediate and short-term changes to bacterial community structure, following surface soil disturbance. Three blocks, each comprising an undisturbed control, and an area disturbed by removing the top 2 cm of soil, were sampled over a time series (0, 7, 14, 21, and 35 days), to investigate changes to bacterial community structure using DNA profiling by terminal restriction fragment length polymorphism. The simulated disturbance did not cause any major shifts in the structure of the bacterial communities over the 35-day sampling period. Ordination showed that the bacterial community composition correlated strongly with soil EC (R² = 0.55) and soil pH (R² = 0.67), rather than the removal of the top 2 cm of surface material. Although the replicate blocks were visually indistinguishable from one another, high local spatial variability of soil chemical properties was found at the study site and different populations of bacterial communities occurred within 2 m of one another, within the same landscape unit. Given the current knowledge of the drivers of bacterial community structure, that is, soil EC, soil pH, and soil moisture content, a follow-up investigation incorporating DNA and RNA-based analyses over a time frame of 2-3 years would lead to a greater understanding of the effects of soil disturbance on bacterial communities

Real-world cardiovascular disease burden in patients with atherosclerotic cardiovascular disease: a comprehensive systematic literature review

<p><b>Objective:</b> Based on randomized controlled trials (RCTs), non-fatal myocardial infarction (MI) rates range between 9 and 15 events per 1000 person-years, ischemic stroke between 4 and 6 per 1000 person-years, CHD death rates between 5 and 7 events per 1000 person-years, and any major vascular event between 28 and 53 per 1000 person-years in patients with atherosclerotic cardiovascular disease (ASCVD). We reviewed global literature on the topic to determine whether the real-world burden of secondary major adverse cardiovascular events (MACEs) is higher among ASCVD patients.</p> <p><b>Methods:</b> We searched PubMed and Embase using MeSH/keywords including cardiovascular disease, secondary prevention and observational studies. Studies published in the last 5 years, in English, with ≥50 subjects with elevated low-density lipoprotein cholesterol (LDL-C) or on statins, and reporting secondary MACEs were included. The Newcastle–Ottawa Scale (NOS) was used to assess the quality of each included study.</p> <p><b>Results:</b> Of 4663 identified articles, 14 studies that reported MACE incidence rates per 1000 person-years were included in the review (NOS grades ranged from 8 to 9; 2 were prospective and 12 were retrospective studies). Reported incidence rates per 1000 person-years had a range (median) of 12.01–39.9 (26.8) for MI, 13.8–57.2 (41.5) for ischemic stroke, 1.0–94.5 (21.1) for CV-related mortality and 9.7–486 (52.6) for all-cause mortality. Rates were 25.8–211 (81.1) for composite of MACEs. Multiple event rates had a range (median) of 60–391 (183) events per 1000 person-years.</p> <p><b>Conclusions:</b> Our review indicates that MACE rates observed in real-world studies are substantially higher than those reported in RCTs, suggesting that the secondary MACE burden and potential benefits of effective CVD management in ASCVD patients may be underestimated if real-world data are not taken into consideration.</p

Multiple <i>Wolbachia </i>strains provide comparative levels of protection against dengue virus infection in <i>Aedes aegypti</i>

The insect bacterium Wolbachia pipientis is being introgressed into Aedes aegypti populations as an intervention against the transmission of medically important arboviruses. Here we compare Ae. aegypti mosquitoes infected with wMelCS or wAlbB to the widely used wMel Wolbachia strain on an Australian nuclear genetic background for their susceptibility to infection by dengue virus (DENV) genotypes spanning all four serotypes. All Wolbachia-infected mosquitoes were more resistant to intrathoracic DENV challenge than their wildtype counterparts. Blocking of DENV replication was greatest by wMelCS. Conversely, wAlbB-infected mosquitoes were more susceptible to whole body infection than wMel and wMelCS. We extended these findings via mosquito oral feeding experiments, using viremic blood from 36 acute, hospitalised dengue cases in Vietnam, additionally including wMel and wildtype mosquitoes on a Vietnamese nuclear genetic background. As above, wAlbB was less effective at blocking DENV replication in the abdomen compared to wMel and wMelCS. The transmission potential of all Wolbachia-infected mosquito lines (measured by the presence/absence of infectious DENV in mosquito saliva) after 14 days, was significantly reduced compared to their wildtype counterparts, and lowest for wMelCS and wAlbB. These data support the use of wAlbB and wMelCS strains for introgression field trials and the biocontrol of DENV transmission. Furthermore, despite observing significant differences in transmission potential between wildtype mosquitoes from Australia and Vietnam, no difference was observed between wMel-infected mosquitoes from each background suggesting that Wolbachia may override any underlying variation in DENV transmission potential