131 research outputs found
The distribution of lung cancer mortality in Cape Town and related factors
Lung cancer, a disease which primarily occurs in urban areas, caused 1130 deaths during 1984 - 1986 in Cape Town. It is the most prevalent cause of cancer death in men and is second only to breast cancer in women. It was responsible for 22,9% of all cancer deaths in Cape Town during the 3-year period. The cartographic representation of standardised mortality ratios shows that the incidence of lung cancer mortality in Cape Town is appreciably higher in men than women, and in coloured people than in white people. Coloured men are the group most at risk. Despite the important role smoking habits play in the aetiology of lung cancer, the results of the ecological analyses show that environmental factors are partly responsible for the incidence of the disease. In the case of white people demographic as well as socioeconomic variables, such as age, home language, religious affiliation and level of education, were identified by the multivariate statistical techniques as associated variables. In the case of coloured people the factors that play a role are chiefly socio-economic ones, such as unemployment, home owner status and type of housing. Positive relationship with low socio-economic status pertains only to coloured people
The bacterial stressosome:a modular system that has been adapted to control secondary messenger signaling
SummaryThe stressosome complex regulates downstream effectors in response to environmental signals. In Bacillus subtilis, it activates the alternative sigma factor σB, leading to the upregulation of the general stress regulon. Herein, we characterize a stressosome-regulated biochemical pathway in Moorella thermoacetica. We show that the presumed sensor, MtR, and the scaffold, MtS, form a pseudo-icosahedral structure like that observed in B. subtilis. The N-terminal domain of MtR is structurally homologous to B. subtilis RsbR, despite low sequence identity. The affinity of the switch kinase, MtT, for MtS decreases following MtS phosphorylation and not because of structural reorganization. Dephosphorylation of MtS by the PP2C type phosphatase MtX permits the switch kinase to rebind the stressosome to reset the response. We also show that MtT regulates cyclic di-GMP biosynthesis through inhibition of a GG(D/E)EF-type diguanylate cyclase, demonstrating that secondary messenger levels are regulated by the stressosome
A Novel Signaling Network Essential for Regulating Pseudomonas aeruginosa Biofilm Development
The important human pathogen Pseudomonas aeruginosa has been linked to numerous biofilm-related chronic infections. Here, we demonstrate that biofilm formation following the transition to the surface attached lifestyle is regulated by three previously undescribed two-component systems: BfiSR (PA4196-4197) harboring an RpoD-like domain, an OmpR-like BfmSR (PA4101-4102), and MifSR (PA5511-5512) belonging to the family of NtrC-like transcriptional regulators. These two-component systems become sequentially phosphorylated during biofilm formation. Inactivation of bfiS, bfmR, and mifR arrested biofilm formation at the transition to the irreversible attachment, maturation-1 and -2 stages, respectively, as indicated by analyses of biofilm architecture, and protein and phosphoprotein patterns. Moreover, discontinuation of bfiS, bfmR, and mifR expression in established biofilms resulted in the collapse of biofilms to an earlier developmental stage, indicating a requirement for these regulatory systems for the development and maintenance of normal biofilm architecture. Interestingly, inactivation did not affect planktonic growth, motility, polysaccharide production, or initial attachment. Further, we demonstrate the interdependency of this two-component systems network with GacS (PA0928), which was found to play a dual role in biofilm formation. This work describes a novel signal transduction network regulating committed biofilm developmental steps following attachment, in which phosphorelays and two sigma factor-dependent response regulators appear to be key components of the regulatory machinery that coordinates gene expression during P. aeruginosa biofilm development in response to environmental cues
Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes
Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat
Semi-Autonomous Revenue Authorities in Sub-Saharan Africa: Silver Bullet or White Elephant
A major component of tax administration reform in sub-Saharan Africa for the last 30 years has been the creation of semi-autonomous revenue authorities (SARAs). The effects of their creation on revenue performance have been much debated, although there are only a few quantitative studies. The core argument of this paper is that existing research suggesting diverse and contradictory outcomes has not taken account of trends in revenue performance in the years before the establishment of SARAs. Allowing for this revenue history our analysis based on 46 countries over the period 1980-2015 provides no robust evidence that SARAs induce an increase in revenue performance. This does not imply that SARAs may not provide benefits for tax collection, but they do not demonstrably increase (or decrease) revenue collected
The distribution of lung cancer mortality in Cape Town and related factors
CITATION: Haldenwang, B. B. 1991. The distribution of lung cancer mortality in Cape Town and related factors. South African Medical Journal, 79:461-465.The original publication is available at http://www.samj.org.zaLung cancer, a disease which primarily occurs in urban areas, caused 1130 deaths during 1984-1988 in Cape Town. It is the most prevalent cause of cancer death in men and is second only to breast cancer in women. It was responsible for 22,9% of all cancer deaths in Cape Town during the 3-year period. The cartographic representation of standardised mortality ratios shows that the incidence of lung cancer mortality in Cape Town is appreciably higher in men than women, and in coloured people than in white people. Coloured men are the group most at risk. Despite the important role smoking habits play in the aetiology of lung cancer, the results of the ecological analyses show that environmental factors are partly responsible for the incidence of the disease. In the case of white people demographic as well as socioeconomic variables, such as age, home language, religious affiliation and level of education, were identified by the multivariate statistical techniques as associated variables. In the case of coloured people the factors that play a role are chiefly socio-economic ones, such as unemployment, home owner status and type of housing. Positive relationship with low socio-economic status pertains only to coloured people.Publisher’s versio
The state of water in South Africa - are we heading for a crisis?
The original publication does not have a website but the html - http://www.anthonyturton.com/admin/my_documents/my_files/A59_Nat_Env_Apr_2009.pdf.The state of water in South Africa has been the subject of widespread public discussions over the past couple of months. Questions asked include: Is SA heading for a water crisis? Does SA have sufficient freshwater resources to sustain both its path of economic growth and its population growth? Is the quality of water deteriorating? Some of these issues are addressed in this Strategy Insights. The recently published Water for Growth & Development Framework (version 7) by DWAF makes a number of high level recom-mendations regarding how government intends to avoid a looming water crisis. Lastly, a couple of pointers are provided on what the business community and industry can do to relieve water stress
Die ruimtelike patrone en beinvloedende omgewingsfaktore van kanker in Kaapstad
Proefskrif (D. Phil.) -- Universiteit van Stellenbosch, 1991.Een kopie mikrofiche.Full text to be digitised and attached to bibliographic record
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