Project description:The South China Sea (SCS) is the largest marginal sea in the western tropical Pacific Ocean and is characterized by complex physicochemical environments. To date, the biogeographic patterns of the microbial communities have rarely been reported at a basin scale in the SCS. In this study, the bacterial assemblages inhabiting the epipelagic zone across 110°E to 119°E along 14°N latitude were uncovered. The vertical stratification of both bacterial taxa and their potential functions were revealed. These results suggest that the water depth-specific environment is a driver of the vertical bacterioplankton distribution. Moreover, the bacterial communities were different between the eastern stations and the western stations, where the environmental conditions were distinct. However, the mesoscale eddy did not show an obvious effect on the bacterial community due to the large distance between the sampling site and the center of the eddy. In addition to the water depth and longitudinal location of the samples, the heterogeneity of the phosphate and salinity concentrations also significantly contributed to the variance in the epipelagic bacterial community in the SCS. To the best of our knowledge, this study is the first to report that the variability in epipelagic bacterioplankton is driven by the physicochemical environment at the basin scale in the SCS. Our results emphasize that the ecological significance of bacterioplankton can be better understood by considering the relationship between the biogeographic distribution of bacteria and the oceanic dynamics processes.
Project description:The diversity of some of the culturable microorganisms associated with marine flora and fauna collected off Vizhinjam and Mulloor coast of South India was evaluated and their bioactive production potential determined. From a total of 24 bacteria, 4 actinomycetes and 8 fungi isolated from diverse marine sources, five bacterial species-BLM3, BSP2, BCS1, BCS4 and BMA6 showed inhibitory activity against at least one of the tested pathogens viz., Klebsiella pneumonia KU1, Pseudomonas aeruginosa VL3, Salmonella enterica typhimurium MTCC 98, Escherichia coli MTCC 40, Micrococcus luteus MTCC 105, Staphylococcus simulans MTCC 3610, Proteus vulgaris MTCC 426, Vibrio fluvialis, Vibrio sp. P3a and Vibrio sp. P3b. The isolated actinomycetes and fungi did not produce significant inhibition zones against the tested pathogens; however, the macroalgal isolated actinomycetes strain AMA1 produced reddish pigment in Starch Casein medium which remained stable till the stationary phase of growth. The marine sediment isolate BCS4, identified as Bacillus sp. showed wide spectrum of activity against the tested Gram positive bacteria, S. simulans MTCC 3610 and Gram negative bacteria, Proteus vulgaris with zone of inhibitions of 25 and 11 mm respectively. Better extraction of the bioactive compound was obtained with ethyl acetate when compared with methanol, benzene and hexane and TLC analysis revealed the presence of an active compound. The 16SrRNA sequencing confirmed the potent strain belong to Bacillus sp. and hence designated Bacillus sp. BCS4.
Project description:Understanding the underlying mechanisms that shape the temporal dynamics of a microbial community has important implications for predicting the trajectory of an ecosystem's response to anthropogenic disturbances. Here, we evaluated the seasonal dynamics of bacterioplankton community composition (BCC) following more than three decades of mariculture disturbance in Xiangshan Bay. Clear seasonal succession and site (fish farm and control site) separation of the BCC were observed, which were primarily shaped by temperature, dissolved oxygen and sampling time. However, the sensitive bacterial families consistently changed in relative abundance in response to mariculture disturbance, regardless of the season. Temporal changes in the BCC followed the time-decay for similarity relationship at both sites. Notably, mariculture disturbance significantly (P?<?0.001) flattened the temporal turnover but intensified bacterial species-to-species interactions. The decrease in bacterial temporal turnover under long-term mariculture disturbance was coupled with a consistent increase in the percentage of deterministic processes that constrained bacterial assembly based on a null model analysis. The results demonstrate that the BCC is sensitive to mariculture disturbance; however, a bacterioplankton community could adapt to a long-term disturbance via attenuating temporal turnover and intensifying species-species interactions. These findings expand our current understanding of microbial assembly in response to long-term anthropogenic disturbances.
Project description:ObjectivesData from generalized epidemic settings have consistently found that patients on antiretroviral therapy (ART) reduce sexual risk behaviours, but how sexual behaviour changes in the general population in response to ART availability, including amongst HIV-uninfected and undiagnosed adults, has not been characterized in these settings.DesignGeneral population open cohort.MethodsWe report trends in sexual behaviour indicators for men aged 17-54 years and women aged 17-49 years in rural KwaZulu-Natal province, based on annual sexual behaviour surveys during ART scale-up from 2005 to 2011. Estimates are adjusted for survey nonparticipation and nonresponse to individual survey items using inverse probability weighting and multiple imputation. Trends are presented by HIV status, knowledge of status, age and marital status.ResultsReports of condom use at last sex with a regular partner increased by 2.6% points per year [95% confidence interval (CI) 1.5%, 3.7%] for men and 4.1% per year (3.0%, 5.3%) for women. Condom use at last sex with a casual partner was high and did not change significantly over the period for both sexes. There were statistically significant declines in the percentage reporting multiple partnerships in the last year and the point prevalence of concurrency. Trends within subgroups were generally consistent with overall estimates.ConclusionWe find no evidence of increased sexual risk-taking following ART availability and protective changes in some behaviours, suggesting that general trends in sexual behaviour are not counter-acting preventive effects of HIV treatment. Continued monitoring of population-level sexual behaviour indicators will be essential to interpret the success of combination-prevention programmes.
Project description:The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3(-), NH4(+) and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation.
Project description:The subtle and cascading effects (e.g., altered interspecific interactions) that anthropogenic stressors have on local ecological assemblages often go unnoticed but are concerning given their importance in ecosystem function. For example, elimination of buffalo from the Serengeti National Park is suggested to have driven increased abundance of smaller antelope as a result of release from competition. The perceived low abundance of small antelope in the contractual Postberg section of the West Coast National Park (the park) has been an ongoing management concern which has been anecdotally attributed to predation by a mesopredator (the caracal, Caracal caracal). However, we hypothesized that the historical overstocking, and consequent overgrazing by larger-bodied managed ungulates would influence small antelope abundance. Using camera traps, we investigated species co-occurrence and temporal activity between small antelope, managed ungulates and caracals in Postberg as well as another part of the park (Langebaan) and a farm outside of the park. Results suggest that small antelope and managed ungulates have a high degree of temporal overlap (Δ = 0.74, 0.79 and 0.86 for the farm, Langebaan and Postberg respectively), while temporal partitioning between small antelope and caracal is apparent (Δ = 0.59). Further, small antelope and managed ungulates appear to occur independently of one another (SIF = 0.91-1 across areas). Managed ungulates were detected almost three times more frequently on fallow lands when compared to the more vegetated sites within the park suggesting that segregated food/cover resources allow for independent occurrence. Small antelope had a much higher probability of occurrence outside of the protected area (e.g., ψ = 0.192 and 0.486 for steenbok at Postberg, Langebaan compared to 0.841 on the farm), likely due to less variable (more intact) habitat outside of the protected area. There is not sufficient evidence to currently warrant management intervention for predators. The small size of the protected area provides limited scope for spatial replication thus reducing possibilities to infer the cause and effect for complex interactions (which would historically have taken place over much larger areas) with negative implications for adaptive management. We recommend continued monitoring over multiple seasons and a wider area to determine the spatial information requirements to inform management of small protected areas.
Project description:BACKGROUND:South Africa's quadruple burden of disease, coupled with health system challenges and other factors, predicts a high burden of disability within the population. Human Resources for Health policy and planning need to take account of this challenge. Occupational therapists are part of the health rehabilitation team, and their supply and status in the workforce need to be better understood. METHODS:The study was a retrospective record-based review of the Health Professions Council of South Africa database from 2002 to 2018. The data obtained from the Health Professions Council of South Africa was analysed for the following variables: geographical location, population groups, age, practice type and sex. Data was entered on a Microsoft Excel spreadsheet and analysed using the Statistical Package for the Social Sciences (SPSS version 22.0). RESULTS:In 2018, there were 5180 occupational therapists registered with the Health Professions Council of South Africa with a ratio of 0.9 occupational therapists per 10 000 population. There has been an average annual increase of 7.1% over the time period of 2002-2018. The majority of occupational therapists are located in the more densely populated and urbanised provinces, namely Gauteng, Western Cape and KwaZulu-Natal. Most of the registered occupational therapists are under the age of 40?years (67.7%). The majority (66%) are classified as white followed by those classified as black and coloured. Females make up 95% of the registered occupational therapists. Nationally, 74.8% of occupational therapists are deployed in the private sector catering for 16% of the population while approximately 25.2% are employed in the public sector catering for 84% of the population. CONCLUSIONS:Under-resourcing and disparities in the profile and distribution of occupational therapy human resources remain an abiding concern which negatively impacts on rehabilitation service provision and equitable health and rehabilitation outcomes.
Project description:Understanding marine bacterioplankton composition and distribution is necessary for improving predictions of ecosystem responses to environmental change. Here, we used 16S rRNA metabarcoding to investigate marine bacterioplankton diversity and identify potential pathogenic bacteria in seawater samples collected in March, May, September, and December 2013 from two sites near Jeju Island, South Korea. We identified 1343 operational taxonomic units (OTUs) and observed that community diversity varied between months. Alpha- and Gamma-proteobacteria were the most abundant classes, and in all months, the predominant genera were Candidatus Pelagibacter, Leisingera, and Citromicrobium. The highest number of OTUs was observed in September, and Vibrio (7.80%), Pseudoalteromonas (6.53%), and Citromicrobium (6.16%) showed higher relative abundances or were detected only in this month. Water temperature and salinity significantly affected bacterial distribution, and these conditions, characteristic of September, were adverse for Aestuariibacter but favored Citromicrobium. Potentially pathogenic bacteria, among which Vibrio (28 OTUs) and Pseudoalteromonas (six OTUs) were the most abundant in September, were detected in 49 OTUs, and their abundances were significantly correlated with water temperature, increasing rapidly in September, the warmest month. These findings suggest that monthly temperature and salinity variations affect marine bacterioplankton diversity and potential pathogen abundance.