Project description:Time-course expression analysis profiling whole blood samples collected from healthy South African adolescents while monitoring their potential acquisition of a Mycobacterium tuberculosis infection.
Project description:Primary objectives: The primary objective is to investigate circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Primary endpoints: circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Project description:Identification of blood biomarkers that prospectively predict progression of Mycobacterium tuberculosis infection to tuberculosis disease might lead to interventions that combat the tuberculosis epidemic. We aimed to assess whether global gene expression measured in whole blood of healthy people allowed identification of prospective signatures of risk of active tuberculosis disease. RESULTS:Between July 6, 2005, and April 23, 2007, we enrolled 6363 from the ACS study and 4466 from independent South African and Gambian cohorts. 46 progressors and 107 matched controls were identified in the ACS cohort. A 16 gene signature of risk was identified. The signature predicted tuberculosis progression with a sensitivity of 66·1% (95% CI 63·2â68·9) and a specificity of 80·6% (79·2â82·0) in the 12 months preceding tuberculosis diagnosis. The risk signature was validated in an untouched group of adolescents (p=0·018 for RNA sequencing and p=0·0095 for qRT-PCR) and in the independent South African and Gambian cohorts (p values <0·0001 by qRT-PCR) with a sensitivity of 53·7% (42·6â64·3) and a specificity of 82·8% (76·7â86) in 12 months preceding tuberculosis. Interpretation: The whole blood tuberculosis risk signature prospectively identified people at risk of developing active tuberculosis, opening the possibility for targeted intervention to prevent the disease. In this prospective cohort study, we followed up healthy, South African adolescents aged 12â18 years from the adolescent cohort study (ACS) who were infected with M tuberculosis for 2 years. We collected blood samples from study participants every 6 months and monitored the adolescents for progression to tuberculosis disease. A prospective signature of risk was derived from whole blood RNA sequencing data by comparing participants who developed active tuberculosis disease (progressors) with those who remained healthy (matched controls). After adaptation to multiplex qRT-PCR, the signature was used to predict tuberculosis disease in untouched adolescent samples and in samples from independent cohorts of South African and Gambian adult progressors and controls. Participants of the independent cohorts were household contacts of adults with active pulmonary tuberculosis disease.
Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. Keywords: comparative genomic indexing analysis
Project description:Genome-wide DNA methylation profiling was conducted in two batches for 56 ǂKhomani San living in the South African Kalahari using the Illumina 450k array on saliva-derived DNA
Project description:We have engineered synthetic gene switches to control and limit Mycoplasma growth for biosafety containment applications. Mycoplasmas have high mutation rates and, the accumulation of mutations that inactivate the circuit is expected. However, the question is how resilient is the kill-switch to mutation and whether it is more sensitive to the accumulation of mutations. Therefore, we did the whole-genome sequencing of the three Mycoplasma biosafety strains, designed in our study, at different passages (p2, p3 and p15) or after IPTG-treatment at passage 3 (p3IPTG)
Project description:48 ǂKhomani San living in the South African Kalahari were genotyped using the Illumina OmniExpress, OmniExpress Plus, and HumanHap550 arrays
Project description:We investigated the effects of the crude extract of a South African medicinal plant, Cotyledon orbiculata, on cell survival of colon (HCT116) cancer cell lines. Using RNASeq, we discovered that the extract interfered with mRNA regulatory pathways. Here, we found that the extract of Cotyledon orbiculata, a South African medicinal plant, had an anti-proliferative effect in cancer cells, mediated by apoptosis induced by alternative splicing of hnRNPA2B1 and BCL2L1.
Project description:RNA was extracted from all instar (insect developmental) stages for both D. noxia biotypes SA1 and SAM with the purpose to capture as many expressed transcripts as possible. South African D. noxia biotype SA1 is known to be the least virulent aphid, while its offspring, the South African D. noxia biotype SAM is the most virulent. The overall purpose of the experiment was to establish a baseline availability of transcripts to the aphids as well as help improve on current genome assemblies. Three biological replicates of 100 aphids each was collected from both biotypes SA1 and SAM that were respectively reared on preference host cultivars. Whole aphids were flash frozen in liquid nitrogen, ground to a powder with micro pistils and RNA was extracted making use of a Qiagen RNeasy kit. Library preparation for sequencing was performed using an Illumina TruSeq Stranded mRNA LT Sample Prep Kit following the TruSeq Stranded mRNA Sample Preparation Guide, Part # 15031047 Rev. E protocol. The replicate samples from the SAM biotype yielded between 120 – 140 million 100bp PE reads and the replicate samples from the SA1 biotype yielded between 113 – 137 million 100bp PE reads (with a Q20 phred score above 98% for all replicates) after sequencing on the NovaSeq6000 system. De novoassembly was performed making use of the Trinity package.