Living with multiple, complex risks of commercial sugarcane farming in KwaZulu-Natal : the role of climate change?

The aim of this research is to examine the contextual environment in which farmers operate so as to improve our understanding of the factors shaping vulnerability to climate risk. A key focus is on the livelihoods of sugarcane farmers, using a case study of small-, medium-scale (emerging) and large-scale sugarcane farmers in the KwaZulu-Natal Midlands area of Eston and its surrounds. A social vulnerability assessment was undertaken under the Sustainable Livelihoods Framework (SLF) to test the hypothesis that climate risk is considered a major contributing factor to the vulnerability of commercial farmers in KwaZulu-Natal and needs to be effectively managed. This involved an investigation into the multiple stresses (both external and internal, on-farm and off-farm, climatic and non climatic) acting on the system. It is clear that climate change risk and variability is a major, but not the sole contributing factor to the vulnerability of commercial farmers in this part of KwaZulu-Natal. Climate change does need to be effectively managed but it will be best done in conjunction with the management of the other multiple and interacting threats and stresses identified in this study. Climate change and vulnerability, as well as the other multiple stresses, are acting on an already vulnerable system, exacerbating and compounding present risks. This research also explored a number of coping and response strategies that commercial farmers have adopted in response to the threats and stresses and investigated particularly, what elements enhance or restrict these strategies (both on-farm and off-farm). These strategies posses potential as possible future adaptation options. It was found that the issues of access to livelihood assets (social, financial, natural/environmental, physical, human, knowledge assets and capital under the SLF) are key to the adaptive capacity and the adaptation strategies that farmers employ. Institutions (both formal and informal) play a pivotal role in this access to livelihood assets both enabling and restricting access. In conclusion, this work determined that a focus on only one element, such as climate change, will not significantly reduce the vulnerability of commercial farmers. There is an interactive, dynamic and multifaceted network present with a number of factors acting within and from outside the system. Political, biophysical, social and economic factors interact and combine to compound vulnerability, requiring more integrative and multiple response strategies

Renting Shacks: Tenancy in the informal housing sector of the Gauteng Province, South Africa

Informal settlements are where a significant proportion of urban population find shelter in the cities of the Global South. In some cities, this settlement type is the norm and urban residence are forced into these areas due to a lack of formal housing capacity. Housing tenure in the informal sector is tenuous and the most vulnerable of this group are those who find rental housing in the sector. The idea of a slumlord within this context is one of exploitation and abuse, this study explores the slumlord tenant relationship within informal settlements in Gauteng, South Africa. The study found that there is a symbiotic relationship between landlords and tenants where the informal economy fills a gap in the low income market. While there are issues of exploitation within the informal rental market, this large, unregulated and growing sector points to a significant need for more low cost housing within the formal sector.

Invasion of Human Cells by a Bacterial Pathogen

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO2 at 37°C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 μl tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy

Phenotypic switching of antibiotic resistance circumvents permanent costs in Staphylococcus aureus

AbstractBacterial antibiotic resistance is often associated with a fitness cost in the absence of the antibiotic [1, 2]. We have examined a resistance mechanism in Staphylococcus aureus that negates these costs. Exposure to gentamicin both in vitro and in vivo has been reported to result in the emergence of a gentamicin-resistant small colony variant (SCV) [3–8]. We show that the emergence of SCVs following exposure to gentamicin results from a rapid switch and that bacteria exposed to cycles of gentamicin followed by antibiotic-free medium repeatedly switched between a resistant SCV and a sensitive parental phenotype (revertants). The fitness of revertants relative to S. aureus with stable gentamicin resistance was greater in drug-free media, which suggests that S. aureus has evolved an inducible and reversible resistance mechanism that circumvents a permanent cost to fitness

The Green Box Project: Environmental Education in a Crate

Although the quality of teaching and learning of geography in many schools is worrying, another more basic problem is that of teachers lacking basic resources to use in their classrooms. Higher education institutions are expected to engage with and be of service to society and its needs. The Green Box Project is reported on as a practical and sustainable solution to address the resource constraints that many teachers of geography contend with; a way of improving the quality of teaching and learning in schools; and a model to be used by higher education institutions for community engagement.https://upjournals.up.ac.za/index.php/jogea/article/view/254

Characterizing the genetic basis of bacterial phenotypes using genome-wide association studies: a new direction for bacteriology.

Genome-wide association studies (GWASs) have become an increasingly important approach for eukaryotic geneticists, facilitating the identification of hundreds of genetic polymorphisms that are responsible for inherited diseases. Despite the relative simplicity of bacterial genomes, the application of GWASs to identify polymorphisms responsible for important bacterial phenotypes has only recently been made possible through advances in genome sequencing technologies. Bacterial GWASs are now about to come of age thanks to the availability of massive datasets, and because of the potential to bridge genomics and traditional genetic approaches that is provided by improving validation strategies. A small number of pioneering GWASs in bacteria have been published in the past 2 years, examining from 75 to more than 3,000 strains. The experimental designs have been diverse, taking advantage of different processes in bacteria for generating variation. Analysis of data from bacterial GWASs can, to some extent, be performed using software developed for eukaryotic systems, but there are important differences in genome evolution that must be considered. The greatest experimental advantage of bacterial GWASs is the potential to perform downstream validation of causality and dissection of mechanism. We review the recent advances and remaining challenges in this field and propose strategies to improve the validation of bacterial GWASs

Cytolytic toxin production by \u3ci\u3eStaphylococcus aureus\u3c/i\u3e is dependent upon the activity of the protoheme IX farnesyltransferase

Staphylococcus aureus is a medically important pathogen with an abundance of virulence factors that are necessary for survival within a host, including the production of cytolytic toxins. The regulation of toxin production is mediated by the Agr quorum sensing system, and a poorly defined post-exponential growth phase signal independent of Agr. As part of a recent genome wide association study (GWAS) to identify novel loci that alter the expression of cytolytic toxins, a polymorphism in the cyoE gene, which encodes a protoheme IX farnesyltransferase, was identified. This enzyme is essential for processing heme into the electron transport chain for use as an electron acceptor. Interestingly, without this enzyme S. aureus were repressed in their ability to secrete cytolytic toxins, and this appears to be mediated through repression of the Agr quorum sensing system. We hypothesize that the loss of electron transport is inducing feedback inhibition of metabolic capabilities that suppress the TCA cycle, and that this coupled with decreased RNAIII transcription prevents synthesis of cytolytic toxins

Promiscuous bacteria have staying power

Being able to take up DNA from their environment might allow pneumococcal bacteria to colonize the human nose and throat for longer periods of time