Genetic sequences derived from suppression subtractive hybridization analysis provides insight into their possible roles in Xanthomonas albilineans

Leaf scald disease (LSD) is caused by the Gram-negative bacterium, Xanthomonas albilineans. Genomic DNA from X. albilineans and Xanthomonas hyacinthi were analyzed by suppression subtractive hybridization (SSH) using X. albilineans as the tester from which unique sequences were sought and X. hyacinthi as the driver. Following the SSH procedure, amplification products within the size range of 100 - 600 bp were generated, purified, directly cloned with the Promega pGEM-T vector cloning kit, and transformed into ultracompetent Escherichia coli X L2-blue MRF’ cells (Stratagene, La Jolla, CA). Clones selected were sequenced (using a Perkin Elmer ABI PRISM Dye terminator cycle sequencing kit and ABI Model 377 DNA sequencer) in one direction with SP6 and T7 primers (Promega). Clone Xa 6 revealed very close homology with a probable bacterioferritin from Pseudomonasaeruginosa. Clone X. albilineans 12 showed 92% homology to the acetate repressor proteins and clone X. albilineans 18 displayed 85% homology to the plasmid pTOM9 from Alcaligenes xylosoxidans.Sequencing data also revealed homology to various hypothetical proteins

Advocacy: Are we teaching it?

Background. Health advocacy has been identified as a key outcome competency in the undergraduate curriculum for a number of health professions by the Health Professions Council of South Africa (HPCSA) and the University of KwaZulu-Natal (UKZN), Durban, SA. Despite health advocacy and activism playing a strong role in the student body and civil society, there has been only limited engagement with the manner in which to teach health advocacy in the health professions literature.Objectives. To assess how the faculty in health professions programmes at UKZN understood health advocacy and how it was covered in the curriculum.Methods. Focus group discussions were held with faculty from undergraduate health professions programmes at the university regarding how health advocacy was understood and how it was being integrated into the current curriculum. A thematic analysis was performed on the transcripts of the focus groups.Results. A range of ways in which health advocacy was understood became apparent in the focus groups, with a few disciplines indicating that they do not cover health advocacy explicitly in the curriculum. Three main focus areas of health advocacy training were identified: for the profession (particularly in the smaller health professions groups); for services within the health system; and for patients or communities. The main points of departure for health advocacy were ethics and human rights and to a much lesser degree social justice. There was generally limited experience of how health advocacy could be taught as a skill and little consensus between the participating disciplines regarding the scope and content of health advocacy training. Advocacy itself was also seen as potentially risky, which could undermine the relationship between the university and the service platform. Similarly, the potential risk to whistle-blowers and the institutional culture in universities and public sector services were also seen as limitations.Conclusions. Ample opportunities were identified for the potential teaching of health advocacy in complex professional and public sector interactions. Dual loyalty was seen to be a key dilemma for how to approach advocacy as part of work-based learning, and linked to considerable risk to the institution, educators and students. The current review offers an exciting opportunity to define more clearly what the outcome competencies of health advocacy are, particularly in the context of transformative health professions education – and how these can be operationalised in the overall curriculum

Characterization of 1,2-dichloroethane (DCA) degrading bacteria isolated from South African waste water

1,2-Dichloroethane (DCA), a potential carcinogen that is toxic to both terrestrial and aquatic ecosystems, is one of the most widely produced chemicals in the modern world. It is used as a metal degreaser, solvent, chemical intermediate and fuel additive. Contamination of the environment with DCA results from accidental spills and poor handling. To date, several bacterial isolates, capable of utilizing this compound as a sole carbon and energy source, have been identified in the northern hemisphere. This report focused on the isolation and characterization of bacterial isolates in the southern hemisphere that are capable of degrading DCA. Samples obtained from a waste water treatment plant in Durban, South Africa were batch cultured in minimal medium containing DCA and repeatedly sub-cultured every five days over a 25 day period. A halogen release assay was performed in order to determine whether individual isolates possessed dehalogenase activity. Confirmation of DCA utilization by bacterial isolates that were positive for dehalogenase activity was done by sub-culturing back into minimal medium containing DCA. It was found that five isolates possessed an identical hydrolytic dehalogenase gene following the design of primers based on known hydrolytic dehalogenase genes. Analysis of 16S rDNA sequences indicated that, all the South African isolates belonged to the genus Ancylobacter and were different from each other.Key words: 1,2- dichloroethane, halogenated hydrocarbon, xenobiotic, dehalogenase

Quadrature Spatial Modulation Orthogonal Frequency Division Multiplexing

This paper investigates the application of quadrature spatial modulation (QSM) to orthogonal frequency division multiplexing (OFDM). In comparison to spatial modulation OFDM (SM-OFDM), the proposed QSM-OFDM achieves an enhanced spectral efficiency by decomposing the amplitude and/or phase modulated signal into its real and imaginary components as the transmitted symbols. The index/indices of the activated transmit antenna(s) are employed to convey additional information. These symbols are transmitted orthogonally to eliminate inter-channel interference with little trade-off in synchronization. The average bit error probability for QSM-OFDM and other schemes, including the SM-OFDM, conventional multiple-input multiple-output (MIMO-OFDM), maximal-ratio combining single-input multiple-output (MRC-OFDM), vertical Bell Laboratories layered space-time architecture (VBLAST-OFDM) and Alamouti-OFDM systems are demonstrated using Monte Carlo simulation. The expressions for the receiver computational complexities in terms of the number of real operations are further derived. QSM-OFDM yields a significant signal-to-noise ratio gain of  dB with little trade-off in computational complexity over SM-OFDM, while substantial gains greater than  dB are evident, when compared to other systems

Uptake of an OHS code of practice by construction firms : barriers and enablers in an Australian industry

The Australian construction industry, reflecting a global trend, is moving towards the implementation of a voluntary code of practice (hereafter VCP) for occupational health and safety. The evidence suggests that highlyvisible clients and project management firms, in addition to their subcontractors, look set to embrace such a code. However, smaller firms not operating in high-profile contracting regimes may prove reticent to adopt a VCP. This paper incorporates qualitative data from a high-profile research project commissioned by Engineers Australia and supported by the Australian Contractors’ Association, Property Council of Australia, Royal Australian Institute of Architects, Association of Consulting Engineers Australia, Australian Procurement and Construction Council, Master Builders Australia and the Australian CRC for Construction Innovation. The paper aims to understand the factors that facilitate or prevent the uptake of the VCP by smaller firms, together with pathways to the adoption of a VCP by industry

An overview of mutational and copy number signatures in human cancer

The genome of each cell in the human body is constantly under assault from a plethora of exogenous and endogenous processes that can damage DNA. If not successfully repaired, DNA damage generally becomes permanently imprinted in cells, and all their progenies, as somatic mutations. In most cases, the patterns of these somatic mutations contain the tell-tale signs of the mutagenic processes that have imprinted and are termed mutational signatures. Recent pan-cancer genomic analyses have elucidated the compendium of mutational signatures for all types of small mutational events, including: (i) single base substitutions; (ii) doublet base substitutions; and (iii) small insertions/deletions. In contrast to small mutational events, where, in most cases, DNA damage is a prerequisite, aneuploidy, which refers to the abnormal number of chromosomes in a cell, usually develops from mistakes during DNA replication. Such mistakes include DNA replication stress, mitotic errors caused by faulty microtubule dynamics, or cohesion defects that contribute to chromosomal breakage and can lead to copy number alterations or even to structural rearrangements. These aberrations also leave behind genomic scars which can be inferred from sequencing as copy number signatures and rearrangement signatures. The analyses of mutational signatures of small mutational events have been extensively reviewed [1-3], so we will not comprehensively re-examine them here. Rather, our focus will be on summarizing the existing knowledge for mutational signatures of copy number alterations. As studying copy number signatures is an emerging field, we briefly summarize the utility that mutational signatures of small mutational events have provided in basic science, cancer treatment, and cancer prevention and we emphasize the future role that copy number signatures may play in each of these fields

Short-term treatment outcomes of children starting antiretroviral therapy in the intensive care unit, general medical wards and outpatient HIV clinics at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa: A retrospective cohort study

Background: Many HIV-infected children are initiated on antiretroviral therapy (ART) during hospitalisation in South Africa (SA). No published data on these outcomes exist.Objectives: To assess the short-term outcomes of children initiated on ART in the intensive care unit (ICU), general medical wards (GMWs) and outpatient HIV clinics (OHCs) at Red Cross War Memorial Children’s Hospital (RCWMCH), Cape Town, SA.Methods: We conducted a retrospective cohort study of HIV-infected children aged <13 years commenced on first-line ART between January 2008 and December 2011. Outcomes included death, virological suppression and changes in CD4 count. Kaplan-Meier estimates, multivariate Cox proportional hazard ratios and logistic regression were used to estimate outcomes at 6 months.Results: One hundred and six children were commenced on ART in the ICU, 509 in the GMWs and 127 in the OHCs; 65.7% of all children were <12 months old. Of children qualifying for rapid ART initiation according to the 2013 national treatment guidelines, 182 (24.9%) started therapy within 7 days of diagnosis. Overall mortality was 6.4% (95% confidence interval (CI) 4.9 - 8.4). Of children remaining in care at RCWMCH, 51.0% achieved a CD4 percentage ≥25% and 62.3% a viral load ≤50 copies/mL 6 months after ART initiation. Mortality was higher in the ICU cohort (13.2%) than in the GMW and OHC cohorts (5.5% and 3.9%, respectively, log-rank p=0.004). Predictors of mortality included moderate underweight (adjusted hazard ratio (aHR) 2.4; 95% CI 1.1 - 5.2), severe underweight (aHR 3.2; 95% CI 1.6 - 6.5), absence of caregiver counselling sessions (aHR 2.9; 95% CI 1.4 - 6.0) and ART initiation in the ICU (aHR 2.6; 95% CI 1.4 - 4.9).Conclusion: These results highlight the importance of understanding the context in which children are initiated on ART, when comparing outcomes in different settings

Development and validation of a single HPLC method for the determination of thirteen pharmaceuticals in bulk and tablet dosage form

The aim of this study was to develop and validate a high performance liquid chromatography (HPLC) method for the determination of thirteen selected pharmaceutical compounds (metformin, amoxicillin, chloroquine, theophylline, trimethoprim, caffeine, norfloxacin, ciprofloxacin, acetylsalicylic acid, doxycycline hyclate, metronidazole, albendazole and cloxacillin) in bulk and tablet dosage form. Chromatographic separation using a Kromasil C18 column, gradient elution with aqueous formic acid (0.1%), methanol and acetonitrile, a UV absorption wavelength of 250 nm and a mobile phase flow rate of 1 mL/min over a 22 min run time was optimized for complete separation of the selected target compounds. The method was validated and results for: linearity, precision, sensitivity, accuracy, specificity, suitability and method robustness were obtained and met the ICH guidelines. Calibration curve correlation coefficients ranged from 0.9985-0.9998 and the percentage relative standard deviations for repeated analysis was below 5%, indicating acceptable method precision. The limits of detection (LODs) and quantification (LOQs) ranged from 0.020-0.27 µg/L and 0.080-0.91 µg/L, respectively. The accuracy study yielded recoveries in the ranges 86.0-102% for pure compounds and 90.9-106% for compounds in tablet dosage form. The method is robust for small or deliberate changes to the chromatographic parameters and found to be appropriate for analysis of tablets for the determination of the thirteen pharmaceuticals.                     KEY WORDS: Pharmaceuticals, Bulk determination, Tablet dosage, High performance liquid chromatography, Method development, ICH guidelines   Bull. Chem. Soc. Ethiop. 2021, 35(1), 17-31. DOI: https://dx.doi.org/10.4314/bcse.v35i1.

Splitting fields and general differential Galois theory

An algebraic technique is presented that does not use results of model theory and makes it possible to construct a general Galois theory of arbitrary nonlinear systems of partial differential equations. The algebraic technique is based on the search for prime differential ideals of special form in tensor products of differential rings. The main results demonstrating the work of the technique obtained are the theorem on the constructedness of the differential closure and the general theorem on the Galois correspondence for normal extensions..Comment: 33 pages, this version coincides with the published on