Morphology, membrane characterization and detection of a bacterium associated with ratoon stunting disease of sugarcane.

Thesis (M.Sc.)-University of Durban-Westville, 1984.Ratoon stunting disease (RSD) of sugarcane was first recognized in 1944 in Queensland, Australia (Steindl, 1961). The disease occurs worldwide and causes significant yield losses, especially during drought. RSD produces no external symptoms except a non-specific stunting (Steindl, 1961). RSD, which was first recorded 1n South Africa in 1953 (Anon., 1960), causes a greater overall loss in yield than any other sugarcane disease in South Africa. Yields of sugarcane are reduced by 20% to 40% and the harvest of affected fields declines progressively with successive ratoons (Anon., 1980b). A virus was originally thought to cause RSD, but in 1973, a coryneform bacterium was implicated as the causal agent (Gillaspie et al., 1973; Teakle et al., 1973). In 1980, our laboratory reported the successful isolation and culture of a coryneform bacterium associated with RSD of sugarcane and was indicated to be the causal agent (Nayiager et al., 1980). The lack of a rapid diagnostic technique applicable to mass screening of sugarcane has hindered progress in the control of the disease. There are two types of commonly used diagnostic tests. One test depends on the evaluation of internal stalk symptoms which may require from two to twenty six weeks to develop (Gillaspie et al., 1966; Matsuoka, 1971; Schexnayder, 1960; Singh, 1969). However, these symptoms are not always present in RSD affected plants and similar symptoms can sometimes result from other causes (Steindl, 1961). The other test involves establishing the presence of the coryneform bacterium associated with diseased plants. The bacterium is visible under high magnification by phase-contrast microscopy (Gillaspie et al., 1973) or by electron microscopy (Teakle et al., 1973). Although identification by the latter methods requires little time, the technology involved severely limits the number of samples that can be examined. Recently, serological techniques have been used (Brlansky et al., 1982; Damann et al., 1977; Davis et al., 1980; Gillaspie, 1978b; Gillaspie et al., 1979; Harris and Gillaspie, 1978) but their success has been limited. Besides problems with diagnosis of the disease, the precise morphology and taxonomy of the causal organism is unclarified. The objectives of this research programme were, firstly, to characterize the cultured intact bacterium and its constituent membranes both ultrastructurally and immunologically, and secondly, to evaluate various immunological methods for detection of the bacterium. This study should contribute to enhancing the taxonomic status of the bacterium and to the use of a rapid diagnostic technique applicable to mass screening of sugarcane. Such a technique should eventually contribute to effective control of RSD

Apoptosis - a comparative study of its role on the trophoblast cell in normotensive and hypertensive placental bed.

Masters Degree. University of KwaZulu-Natal, Durban.Abstract available in PDF

Chloroethenes contaminants in the environment: Still a cause for concern

Prior to 1980, chloroethenes were generally believed to be recalcitrant to degradation. Efforts to remediate sites polluted by this group of compounds were thus limited to the ineffective and tedious pump-and-treat method. The environmental significance of chloroethenes and the absence of effective alternative physical remediation methods have warranted intense scientific investigation into the role of microorganisms for detoxifying these environmentally important compounds to benign products. Several microbial mechanisms have therefore been identified to significantly degrade these compounds in soil and ground water polluted systems. This paper provides a mini-review of such mechanisms with the view of understanding the biodegradation processes for better exploitation for bioremediation of chloroethene contaminants, which continue to be of serious environmental challenges

Prevalence of gonococcal and chlamydial infections among men who have sex with men in sub-Saharan Africa: protocol for a systematic review and meta-analysis

Abstract Background Bacterial sexually transmitted infections (STIs) including Neisseria gonorrhoeae and Chlamydia trachomatis are common in men who have sex with men (MSM). These infections increase the risk of acquiring and transmitting human immunodeficiency virus (HIV) in this key population. Access to MSM in many countries in sub-Saharan Africa remains generally difficult due to discrimination or criminalization of their sexual orientation which could lead to depression and risky sexual practices associated with prevalence. This protocol therefore proposes to undertake a systematic review and meta-analysis of literature on the prevalence of gonococcal and chlamydial infections among MSM in Sub-Saharan Africa. Methods This review which aims to ascertain the pooled prevalence and risk factors of these infections in sub-Saharan Africa’s MSM population will follow the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines. The search strategy will review relevant articles from the following databases: PubMed, Scopus, ISI Web of Science and the Directory of Open Access Journals (DOAJ). Articles screening for eligibility and data extraction will be conducted by two independent reviewers. All discrepancies will be resolved by the third and fourth reviewers. Heterogeneity in studies will be evaluated using the I 2 statistic and where heterogeneity is high and significant, a random effect model will be used to estimate the pooled prevalence. Publication bias will be assessed using the Doi plot. Extracted data will be analysed using MetaXL add-on for Microsoft excel. Data will be presented in tables and graphically presented in forest plots. Discussion In this study, we anticipate being able to systematically determine the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis among MSM as well as explore possible risk factors associated with prevalence. The outcomes of the systematic review and meta-analyses will serve to support researchers and public health stakeholders in identifying healthcare priorities and in addressing issues pertaining to the overall wellbeing of the MSM community. Systematic review registration PROSPERO CRD4202232709