Bheki Mseleku is widely considered one of the most accomplished jazz musicians to have emerged from South Africa. His music has a profound significance in recalling and giving emphasis to that aspect ...of the African American jazz tradition originating in the rhythms and melodies of Africa. The influences of Zulu traditional music, South African township, classical music and American jazz are clearly evident and combine to create an exquisite and particularly lyrical style, evoking a sense of purity and peace that embraces the spiritual healing quality central to his musical inspiration. The Artistry of Bheki Mseleku is an in-depth study of his musical style and includes annotated transcriptions and analysis of a selection of compositions and improvisations from his most acclaimed albums including ‘Celebration’, ‘Timelessness’, ‘Star Seeding’, ‘Beauty of Sunrise’ and ‘Home at Last’. Mseleku recorded with several American jazz greats including Ravi Coltrane, Joe Henderson, Pharoah Sanders, Charlie Haden, Billy Higgins and Abbey Lincoln. His music serves as a vital link to the African–American musical art form that inspired many of the South African jazz legends.
Bacterial communities provide important services. They break down pollutants, municipal waste and ingested food, and they are the primary means by which organic matter is recycled to plants and other ...autotrophs. However, the processes that determine the rate at which these services are supplied are only starting to be identified. Biodiversity influences the way in which ecosystems function, but the form of the relationship between bacterial biodiversity and functioning remains poorly understood. Here we describe a manipulative experiment that measured how biodiversity affects the functioning of communities containing up to 72 bacterial species constructed from a collection of naturally occurring culturable bacteria. The experimental design allowed us to manipulate large numbers of bacterial species selected at random from those that were culturable. We demonstrate that there is a decelerating relationship between community respiration and increasing bacterial diversity. We also show that both synergistic interactions among bacterial species and the composition of the bacterial community are important in determining the level of ecosystem functioning.
Experiments that manipulate species richness and measure ecosystem functioning attempt to separate the effects of species richness (the number of species) from those of species identity. We introduce ...an experimental design that ensures that each species is selected the same number of times at each level of species richness. In combination with a linear model analysis, this approach is able to unambiguously partition the variance due to different species identities and the variance due to nonlinear species richness, a proxy measure for interactions among species. Our design and analysis provide several advantages over methods that are currently used. First, the linear model method has the potential to directly estimate the role of various ecological mechanisms (e.g., competition, facilitation) rather than the consequences of those mechanisms (e.g., the “complementarity effect”). Second, unlike other methods that are currently used, this one is able to estimate the impact of diversity when the contribution of individual species in a mixture is unknown.
Plasmids are important mobile elements that can facilitate genetic exchange and local adaptation within microbial communities. We compared the sequences of four co‐occurring pQBR family environmental ...mercury resistance plasmids and measured their effects on competitive fitness of a Pseudomonas fluorescens SBW25 host, which was isolated at the same field site. Fitness effects of carriage differed between plasmids and were strongly context dependent, varying with medium, plasmid status of competitor and levels of environmental mercury. The plasmids also varied widely in their rates of conjugation and segregational loss. We found that few of the plasmid‐borne accessory genes could be ascribed functions, although we identified a putative chemotaxis operon, a type IV pilus‐encoding cluster and a region encoding putative arylsulfatase enzymes, which were conserved across geographically distant isolates. One plasmid, pQBR55, conferred the ability to catabolize sucrose. Transposons, including the mercury resistance Tn5042, appeared to have been acquired by different pQBR plasmids by recombination, indicating an important role for horizontal gene transfer in the recent evolution of pQBR plasmids. Our findings demonstrate extensive genetic and phenotypic diversity among co‐occurring members of a plasmid community and suggest a role for environmental heterogeneity in the maintenance of plasmid diversity.
Faecal microbiota transplant (FMT) is an established and effective treatment for recurrent Clostridioides difficile infection (CDI) and has many other potential clinical applications. However, ...preparation and quality of FMT is poorly standardised and clinical studies are hampered by a lack of well-defined FMT formulations that meet regulatory standards for medicines. As an alternative to FMT suspensions for administration by nasojejunal tube or colonoscopy, which is invasive and disliked by many patients, this study aimed to develop a well-controlled, standardised method for manufacture of lyophilised FMT capsules and to provide stability data allowing storage for extended time periods. Faecal donations were collected from healthy, pre-screened individuals, homogenised, filtered and centrifuged to remove dietary matter. The suspension was centrifuged to pellet bacteria, which were resuspended with trehalose and lyophilised to produce a powder which was filled into 5 enteric-coated capsules (size 0). Live-dead bacterial cell quantitative PCR assay showed <10 fold viable bacterial load reduction through the manufacturing process. No significant loss of viable bacterial load was observed after storage at -80 °C for 36 weeks (p = 0.24, n = 5). Initial clinical experience demonstrated that the capsules produced clinical cure in patients with CDI with no adverse events reported (n = 7). We provide the first report of a detailed manufacturing protocol and specification for an encapsulated lyophilised formulation of FMT. As clinical trials into intestinal microbiota interventions proceed, it is important to use a well-controlled investigational medicinal product in the studies so that any beneficial results can be replicated in clinical practice.
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Although anaerobic bacteria exist in abundance in cystic fibrosis (CF) airways, their role in disease progression is poorly understood. We hypothesized that the presence and relative abundance of the ...most prevalent, live, anaerobic bacteria in sputum of adults with CF were associated with adverse clinical outcomes. This is the first study to prospectively investigate viable anaerobic bacteria present in the sputum microbiota and their relationship with long-term outcomes in adults with CF. We performed 16S rRNA analysis using a viability quantitative PCR technique on sputum samples obtained from a prospective cohort of 70 adults with CF and collected clinical data over an 8 year follow-up period. We examined the associations of the ten most abundant obligate anaerobic bacteria present in the sputum with annual rate of FEV
change. The presence of
and
were associated with a greater annual rate of FEV
change; -52.3 ml yr
(95 % CI-87.7;-16.9), -67.9 ml yr
(95 % CI-115.6;-20.1), respectively. Similarly, the relative abundance of these live organisms were associated with a greater annual rate of FEV
decline of -3.7 ml yr
(95 % CI: -6.1 to -1.3,
=0.003) and -5.3 ml yr
(95 % CI: -8.7 to -1.9,
=0.002) for each log
increment of abundance, respectively. The presence and relative abundance of certain anaerobes in the sputum of adults with CF are associated with a greater rate of long-term lung function decline. The pathogenicity of anaerobic bacteria in the CF airways should be confirmed with further longitudinal prospective studies with a larger cohort of participants.
High-throughput pyrosequencing and quantitative PCR (Q-PCR) analysis offer greatly improved accuracy and depth of characterisation of lower respiratory infections. However, such approaches suffer ...from an inability to distinguish between DNA derived from viable and non-viable bacteria. This discrimination represents an important step in characterising microbial communities, particularly in contexts with poor clearance of material or high antimicrobial stress, as non-viable bacteria and extracellular DNA can contribute significantly to analyses. Pre-treatment of samples with propidium monoazide (PMA) is an effective approach to non-viable cell exclusion (NVCE). However, the impact of NVCE on microbial community characteristics (abundance, diversity, composition and structure) is not known. Here, adult cystic fibrosis (CF) sputum samples were used as a paradigm. The effects of PMA treatment on CF sputum bacterial community characteristics, as analysed by pyrosequencing and enumeration by species-specific (Pseudomonas aeruginosa) and total bacterial Q-PCR, were assessed. At the local community level, abundances of both total bacteria and of P. aeruginosa were significantly lower in PMA-treated sample portions. Meta-analysis indicated no overall significant differences in diversity; however, PMA treatment resulted in a significant alteration in local community membership in all cases. In contrast, at the metacommunity level, PMA treatment resulted in an increase in community evenness, driven by an increase in diversity, predominately representing rare community members. Importantly, PMA treatment facilitated the detection of both recognised and emerging CF pathogens, significantly influencing 'core' and 'satellite' taxa group membership. Our findings suggest failure to implement NVCE may result in skewed bacterial community analyses.
Microorganisms operate at a range of spatial and temporal scales acting as key drivers of ecosystem properties. Therefore, many key questions in microbial ecology require the consideration of both ...spatial and temporal scales. Spatial scaling, in particular the species-area relationship (SAR), has a long history in ecology and has recently been addressed in microbial ecology. However, the temporal analogue of the SAR, the species-time relationship, has received far less attention even in the science of general ecology. Here we focus upon the role of temporal scaling in microbial ecological patterns by coupling molecular characterization of bacterial communities in discrete island (bioreactor) systems with a macroecological approach. Our findings showed that the temporal scaling exponent (slope), and therefore taxa turnover of the bacterial taxa-time relationship decreased as selective pressure (industrial wastewater concentration) increased. Also, as the concentration of industrial wastewater increased across the bioreactors, we observed a gradual switch from stochastic community assembly to more deterministic (niche)-based considerations. The identification of broad-scale statistical patterns is particularly relevant to microbial ecology, as it is frequently difficult to identify individual species or their functions. In this study, we identify wide-reaching statistical patterns of diversity and show that they are shaped by the prevalent underlying ecological factors.
Patterns of taxa abundance distributions are the result of the combined effects of historical and biological processes and as such are central to ecology. It is accepted that a taxa abundance ...distribution for a given community of animals or plants following a perturbation will typically change in structure from one of high evenness to increasing dominance. Subsequently, such changes in evenness have been used as indicators of biological integrity and environmental assessment. Here, using replicated experimental treehole microcosms perturbed with different concentrations of the pollutant pentachlorophenol, we investigated whether changes in bacterial community structure would reflect the effects of anthropogenic stress in a similar manner to larger organisms. Community structure was visualized using rank-abundance plots fitted with linear regression models. The slopes of the regression models were used as a descriptive statistic of changes in evenness over time. Our findings showed that bacterial community structure reflected the impact and the recovery from an anthropogenic disturbance. In addition, the intensity of impact and the rate of recovery to pre-perturbation structure were dose-dependent. These properties of bacterial community structures may potentially provide a metric for environmental assessment and regulation.
Larger Islands House More Bacterial Taxa Bell, Thomas; Ager, Duane; Song, Ji-Inn ...
Science (American Association for the Advancement of Science),
06/2005, Letnik:
308, Številka:
5730
Journal Article
Recenzirano
The power law that describes the relationship between species richness and area size is one of the few generalizations in ecology, but recent studies show that this relationship differs for microbes. ...We demonstrate that the natural bacterial communities inhabiting small aquatic islands (treeholes) do indeed follow the species-area law. The result requires a re-evaluation of the current understanding of how natural microbial communities operate and implies that analogous processes structure both microbial communities and communities of larger organisms.
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