A5020113287- Plant Stress Responses and Tolerance
- Photosynthetic Processes and Mechanisms
- Plant Molecular Biology Research
- Tuberculosis Research and Epidemiology
- Plant-Microbe Interactions and Immunity
- SARS-CoV-2 and COVID-19 Research
- COVID-19 Clinical Research Studies
- Plant tissue culture and regeneration
- Gene expression and cancer classification
- Respiratory viral infections research
- SARS-CoV-2 detection and testing
- Plant responses to elevated CO2
- Neurobiology and Insect Physiology Research
- Plant Pathogenic Bacteria Studies
- Plant Reproductive Biology
- Nitric Oxide and Endothelin Effects
- Blood disorders and treatments
- HIV/AIDS drug development and treatment
- Respiratory Support and Mechanisms
- Biochemical and Structural Characterization
- Long-Term Effects of COVID-19
- Physiological and biochemical adaptations
- Receptor Mechanisms and Signaling
- Nematode management and characterization studies
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
University of Cape Town
2020-2024
South African Medical Research Council
2021-2024
South African Tuberculosis Vaccine Initiative
2021-2024
Stellenbosch University
2019-2022
Lung Institute
2020-2021
King Abdullah University of Science and Technology
2010-2018
University of the Western Cape
2007-2009
Institute of Bioinformatics
2008-2009
Deakin University
1999-2002
Rationale: Improving treatment outcomes while reducing drug toxicity and shortening the duration to ∼6 months remains an aspirational goal for of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). Objectives: To conduct a multicenter randomized controlled trial in adults with MDR/RR-TB (i.e., without resistance fluoroquinolones or aminoglycosides). Methods: Participants were randomly assigned (1:1 ratio) ∼6-month all-oral regimen that included levofloxacin, bedaquiline,...
The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the similarly interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has clock-mediated variation resistance virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), being least susceptible infection subjective morning. We suggest increased Pst observed morning Col-0 results from modulation of...
Abstract Background The carotenoids are pure isoprenoids that essential components of the photosynthetic apparatus and coordinately synthesized with chlorophylls in chloroplasts. However, little is known about mechanisms regulate carotenoid biosynthesis or coordinate this synthesis other plastidial isoprenoid-derived compounds, including quinones, gibberellic acid abscisic acid. Here, a comprehensive transcriptional analysis individual isoprenoid-related pathway genes was performed order to...
Background Second messengers have a key role in linking environmental stimuli to physiological responses. One such messenger, guanosine 3′,5′-cyclic monophosphate (cGMP), has long been known be an essential signaling molecule many different processes higher plants, including biotic stress To date, however, the guanylyl cyclase (GC) enzymes that catalyze formation of cGMP from GTP largely remained elusive plants. Principal Findings We identified Arabidopsis receptor type wall associated...
Rationale: In the upper respiratory tract replicating (culturable) SARS-CoV-2 is recoverable for ~ 4 to 8 days after symptom onset, however, there paucity of data about frequency or duration virus in lower (i.e. human lung). Objectives: We undertook lung tissue sampling (needle biopsy), shortly death, 42 mechanically ventilated decedents during Beta and Delta waves. An independent group 18 ambulatory patents served as a control group. Methods: Lung biopsy cores from underwent viral culture,...
BackgroundGuanylyl cyclases (GCs) catalyze the formation of second messenger guanosine 3′,5′-cyclic monophosphate (cGMP) from 5′-triphosphate (GTP). Cyclic GMP has been implicated in an increasing number plant processes, including responses to abiotic stresses such as dehydration and salt, well hormones.Principle FindingsHere we used a rational search strategy based on conserved functionally assigned residues catalytic centre annotated GCs identify candidate Arabidopsis thaliana show that...
Here, we analyse the temporal signatures of ozone (O3)-induced hydrogen peroxide(H2O2) and nitric oxide (NO) role second messenger guanosine3′,5′-cyclic monophosphate (cGMP) in transcriptional changes genes diagnostic for biotic abiotic stress responses. Within 90 min O3 induced H2O2 NO peaks demonstrate that donors cause rapid accumulation tobacco (Nicotiana tabacum) leaf. Ozone also causes highly significant, late (> 2 h) sustained cGMP increases, suggesting may not be required all early...
Soil salinization is increasing globally, driving a reduction in crop yields that threatens food security. Salinity stress reduces plant growth by exerting two stresses on plants: rapid shoot ion-independent effects which are largely osmotic and delayed ionic specific to salinity stress. In this study we set out delineate the from of Arabidopsis thaliana plants were germinated grown for weeks media supplemented with 50, 75, 100, or 125 mM NaCl (that imposes both an stress) iso-osmolar...
Abstract Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus largely unclarified. We performed size-fractionated sampling (Andersen cascade impactor) evaluated viral culturability in human cell lines (infectiousness), genetics, host immunity ambulatory participants with COVID-19. Sixty-one percent (27/44) 50% (22/44) emitted variant-specific culture-positive aerosols <10μm...
Cyclic nucleotides have been shown to play important signaling roles in many physiological processes plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent mechanisms since the downstream target proteins remain unknown. This largely due fact that bioinformatics searches fail identify plant homologs of protein kinases phosphodiesterases are main targets animals. An affinity purification technique was used nucleotide binding Arabidopsis...
Abstract Background Plant natriuretic peptides (PNPs) are a class of systemically mobile molecules distantly related to expansins. While several physiological responses PNPs have been reported, their biological role has remained elusive. Here we use combination expression correlation analysis, meta-analysis gene profiles in response specific stimuli and selected mutants, promoter content analysis infer the Arabidopsis thaliana PNP, AtPNP-A. Results A ontology AtPNP-A 25 most correlated genes...
Summary Most metal hyperaccumulating plants accumulate nickel, yet the molecular basis of Ni hyperaccumulation is not well understood. We chose Senecio coronatus to investigate this phenomenon as species displays marked variation in shoot content across ultramafic outcrops Barberton Greenstone Belt (South Africa), thus allowing an intraspecific comparative approach be employed. No correlation between soil and contents was observed, suggesting that has a genetic rather than environmental...
The second messenger, 3', 5'-cyclic monophosphate (cGMP), is a critical component of many different processes in plants while guanylyl cyclases that catalyse the formation cGMP from GTP have remained somewhat elusive higher plants. Consequently, two major aims are discovery novel GCs and identification mediated processes. Recently, we reported temporal signatures ozone (O3)-induced hydrogen peroxide (H2O2) nitric oxide (NO) generation, their effect on consequent transcriptional changes genes...
RATIONALE: The utility of heated and humidified high-flow nasal oxygen (HFNO) for severe COVID-19-related hypoxaemic respiratory failure (HRF), particularly in settings with limited access to intensive care unit (ICU) resources, remains unclear, predictors outcome have been poorly studied.METHODS: We included consecutive patients HRF treated HFNO awake proning at two tertiary hospitals Cape Town, South Africa. primary was the proportion who were successfully weaned from HFNO, whilst...
Second messengers have a key role in linking environmental stimuli to physiological responses. One such messenger, cGMP, has long been known be critical many different processes higher plants while guanylyl cyclases (GCs), enzymes that catalyse the formation of cGMP from GTP largely remained elusive. This is somewhat surprising considering unicellular green alga Chlamydomonas reinhardtii contains > 90 annotated GCs. We recently shown (PLoS ONE 2(5): e449) recombinant cytoplasmic domain...
Mycobacterium tuberculosis (M.tb) causes (TB) and remains one of the leading mortality due to an infectious pathogen. Host immune responses have been implicated in driving progression from infection severe lung disease. We analyzed longitudinal RNA sequencing (RNAseq) data whole blood 74 TB progressors whose samples were grouped into four six-month intervals preceding diagnosis (the GC6-74 study). additionally RNAseq independent cohort 90 patients with positron emission tomography-computed...
Evidence suggests that shared pathophysiological mechanisms in neuropsychiatric disorders (NPDs) may contribute to risk and resilience. We used single-gene network-level transcriptomic approaches investigate disorder-specific processes underlying posttraumatic stress disorder (PTSD), Parkinson's disease (PD) schizophrenia a South African sample. RNA-seq was performed on blood obtained from cases controls each cohort. Gene expression weighted gene correlation network analyses (WGCNA) were...
We have recently reported (Plant Physiology 2006; 142:595-608) that ozone (O3) can inhibit mitochondrial respiration and induce activation of the alternative oxidase (AOX) pathway in particular AOX1a tobacco. While O3 causes H2O2, early leaf nitric oxide (NO) as well transient ethylene (ET) accumulation, levels jasmonic acid 12-oxo-phytodienoic remained unchanged. It was shown both, NO ET dependent pathways transcription by O3. AOX plays a role reducing reactive oxygen species (ROS) which...