Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
BMC Med ; 17(1): 60, 2019 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-30862316

RESUMEN

BACKGROUND: There are over 200 million reported cases of malaria each year, and most children living in endemic areas will experience multiple episodes of clinical disease before puberty. We set out to understand how frequent clinical malaria, which elicits a strong inflammatory response, affects the immune system and whether these modifications are observable in the absence of detectable parasitaemia. METHODS: We used a multi-dimensional approach comprising whole blood transcriptomic, cellular and plasma cytokine analyses on a cohort of children living with endemic malaria, but uninfected at sampling, who had been under active surveillance for malaria for 8 years. Children were categorised into two groups depending on the cumulative number of episodes experienced: high (≥ 8) or low (< 5). RESULTS: We observe that multiple episodes of malaria are associated with modification of the immune system. Children who had experienced a large number of episodes demonstrated upregulation of interferon-inducible genes, a clear increase in circulating levels of the immunoregulatory cytokine IL-10 and enhanced activation of neutrophils, B cells and CD8+ T cells. CONCLUSION: Transcriptomic analysis together with cytokine and immune cell profiling of peripheral blood can robustly detect immune differences between children with different numbers of prior malaria episodes. Multiple episodes of malaria are associated with modification of the immune system in children. Such immune modifications may have implications for the initiation of subsequent immune responses and the induction of vaccine-mediated protection.


Asunto(s)
Enfermedades del Sistema Inmune/inmunología , Malaria/inmunología , Niño , Preescolar , Humanos
2.
PLoS Comput Biol ; 13(9): e1005616, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28910280

RESUMEN

Bioinformatics skills have become essential for many research areas; however, the availability of qualified researchers is usually lower than the demand and training to increase the number of able bioinformaticians is an important task for the bioinformatics community. When conducting training or hands-on tutorials, the lack of control over the analysis tools and repositories often results in undesirable situations during training, as unavailable online tools or version conflicts may delay, complicate, or even prevent the successful completion of a training event. The eBioKit is a stand-alone educational platform that hosts numerous tools and databases for bioinformatics research and allows training to take place in a controlled environment. A key advantage of the eBioKit over other existing teaching solutions is that all the required software and databases are locally installed on the system, significantly reducing the dependence on the internet. Furthermore, the architecture of the eBioKit has demonstrated itself to be an excellent balance between portability and performance, not only making the eBioKit an exceptional educational tool but also providing small research groups with a platform to incorporate bioinformatics analysis in their research. As a result, the eBioKit has formed an integral part of training and research performed by a wide variety of universities and organizations such as the Pan African Bioinformatics Network (H3ABioNet) as part of the initiative Human Heredity and Health in Africa (H3Africa), the Southern Africa Network for Biosciences (SAnBio) initiative, the Biosciences eastern and central Africa (BecA) hub, and the International Glossina Genome Initiative.


Asunto(s)
Investigación Biomédica/educación , Biología Computacional/educación , Biología Computacional/métodos , Programas Informáticos , África , Investigación Biomédica/organización & administración , Biología Computacional/organización & administración , Computadores , Países en Desarrollo , Humanos , Interfaz Usuario-Computador
3.
Virus Genes ; 50(2): 303-9, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25645905

RESUMEN

Twelve complete African swine fever virus (ASFV) genome sequences are currently publicly available and these include only one sequence from East Africa. We describe genome sequencing and annotation of a recent pig-derived p72 genotype IX, and a tick-derived genotype X isolate from Kenya using the Illumina platform and comparison with the Kenya 1950 isolate. The three genomes constitute a cluster that was phylogenetically distinct from other ASFV genomes, but 98-99 % conserved within the group. Vector-based compositional analysis of the complete genomes produced a similar topology. Of the 125 previously identified 'core' ASFV genes, two ORFs of unassigned function were absent from the genotype IX sequence which was 184 kb in size as compared to 191 kb for the genotype X. There were multiple differences among East African genomes in the 360 and 110 multicopy gene families. The gene corresponding to 360-19R has transposed to the 5' variable region in both genotype X isolates. Additionally, there is a 110 ORF in the tick-derived genotype X isolate formed by fusion of 13L and 14L that is unique among ASFV genomes. In future, functional analysis based on the variations in the multicopy families may reveal whether they contribute to the observed differences in virulence between genotpye IX and X viruses.


Asunto(s)
Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/aislamiento & purificación , Fiebre Porcina Africana/virología , Genoma Viral , Virus de la Fiebre Porcina Africana/clasificación , Animales , Secuencia de Bases , Genotipo , Kenia , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Porcinos
4.
Vet Res ; 44: 86, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-24083845

RESUMEN

Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Camelus , Variación Genética , Infecciones Estreptocócicas/veterinaria , Streptococcus agalactiae/genética , Resistencia a la Tetraciclina , Tetraciclina/farmacología , Animales , Proteínas Bacterianas/metabolismo , Humanos , Kenia , Tipificación de Secuencias Multilocus/veterinaria , Filogenia , Reacción en Cadena de la Polimerasa/veterinaria , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/metabolismo
5.
Theor Appl Genet ; 124(4): 685-95, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22069119

RESUMEN

The availability of genomic resources can facilitate progress in plant breeding through the application of advanced molecular technologies for crop improvement. This is particularly important in the case of less researched crops such as cassava, a staple and food security crop for more than 800 million people. Here, expressed sequence tags (ESTs) were generated from five drought stressed and well-watered cassava varieties. Two cDNA libraries were developed: one from root tissue (CASR), the other from leaf, stem and stem meristem tissue (CASL). Sequencing generated 706 contigs and 3,430 singletons. These sequences were combined with those from two other EST sequencing initiatives and filtered based on the sequence quality. Quality sequences were aligned using CAP3 and embedded in a Windows browser called HarvEST:Cassava which is made available. HarvEST:Cassava consists of a Unigene set of 22,903 quality sequences. A total of 2,954 putative SNPs were identified. Of these 1,536 SNPs from 1,170 contigs and 53 cassava genotypes were selected for SNP validation using Illumina's GoldenGate assay. As a result 1,190 SNPs were validated technically and biologically. The location of validated SNPs on scaffolds of the cassava genome sequence (v.4.1) is provided. A diversity assessment of 53 cassava varieties reveals some sub-structure based on the geographical origin, greater diversity in the Americas as opposed to Africa, and similar levels of diversity in West Africa and southern, eastern and central Africa. The resources presented allow for improved genetic dissection of economically important traits and the application of modern genomics-based approaches to cassava breeding and conservation.


Asunto(s)
Genes de Plantas/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Manihot/genética , Raíces de Plantas/genética , Polimorfismo de Nucleótido Simple/genética , África , Mapeo Cromosómico , ADN Complementario/genética , ADN de Plantas/genética , Etiquetas de Secuencia Expresada , Biblioteca de Genes , Genotipo , Manihot/crecimiento & desarrollo , Filogenia , Raíces de Plantas/crecimiento & desarrollo
6.
PLoS One ; 16(1): e0245910, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33481909

RESUMEN

Across the water sector, Escherichia coli is the preferred microbial water quality indicator and current guidance upholds that it indicates recent faecal contamination. This has been challenged, however, by research demonstrating growth of E. coli in the environment. In this study, we used whole genome sequencing to investigate the links between E. coli and recent faecal contamination in drinking water. We sequenced 103 E. coli isolates sampled from 9 water supplies in rural Kitui County, Kenya, including points of collection (n = 14) and use (n = 30). Biomarkers for definitive source tracking remain elusive, so we analysed the phylogenetic grouping, multi-locus sequence types (MLSTs), allelic diversity, and virulence and antimicrobial resistance (AMR) genes of the isolates for insight into their likely source. Phylogroup B1, which is generally better adapted to water environments, is dominant in our samples (n = 69) and allelic diversity differences (z = 2.12, p = 0.03) suggest that naturalised populations may be particularly relevant at collection points with lower E. coli concentrations (<50 / 100mL). The strains that are more likely to have originated from human and/or recent faecal contamination (n = 50), were found at poorly protected collection points (4 sites) or at points of use (12 sites). We discuss the difficulty of interpreting health risk from E. coli grab samples, especially at household level, and our findings support the use of E. coli risk categories and encourage monitoring that accounts for sanitary conditions and temporal variability.


Asunto(s)
Agua Potable/microbiología , Escherichia coli/aislamiento & purificación , Calidad del Agua , Abastecimiento de Agua , Escherichia coli/genética , Humanos , Kenia , Secuenciación Completa del Genoma
7.
Front Microbiol ; 12: 673128, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34248882

RESUMEN

Coral reefs face an increased number of environmental threats from anthropomorphic climate change and pollution from agriculture, industries and sewage. Because environmental changes lead to their compositional and functional shifts, coral reef microbial communities can serve as indicators of ecosystem impacts through development of rapid and inexpensive molecular monitoring tools. Little is known about coral reef microbial communities of the Western Indian Ocean (WIO). We compared taxonomic and functional diversity of microbial communities inhabiting near-coral seawater and sediments from Kenyan reefs exposed to varying impacts of human activities. Over 19,000 species (bacterial, viral and archaeal combined) and 4,500 clusters of orthologous groups of proteins (COGs) were annotated. The coral reefs showed variations in the relative abundances of ecologically significant taxa, especially copiotrophic bacteria and coliphages, corresponding to the magnitude of the neighboring human impacts in the respective sites. Furthermore, the near-coral seawater and sediment metagenomes had an overrepresentation of COGs for functions related to adaptation to diverse environments. Malindi and Mombasa marine parks, the coral reef sites closest to densely populated settlements were significantly enriched with genes for functions suggestive of mitigation of environment perturbations including the capacity to reduce intracellular levels of environmental contaminants and repair of DNA damage. Our study is the first metagenomic assessment of WIO coral reef microbial diversity which provides a much-needed baseline for the region, and points to a potential area for future research toward establishing indicators of environmental perturbations.

8.
PLoS One ; 15(5): e0231852, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32469885

RESUMEN

BACKGROUND: The crisis of antimicrobial resistance is already here with us, affecting both humans and animals alike and very soon, small cuts and surgeries will become life threatening. This study aimed at determine the whole genome sequences of multi-drug resistant Escherichia coli isolated in a Pastoralist Community of Western Uganda: phylogenomic changes, virulence and resistant genes. METHODS: This was a laboratory based cross sectional study. Bacterial isolates analyzed in this study were 42 multidrug resistant E. coli isolated from stool samples from both humans (n = 30) and cattle (n = 12) in pastoralist communities collected between January 2018-March 2019. Most of the isolates (41/42) were resistant to three or more antibiotics (multi-drug resistant) and 21/42 isolates were ESBL producers; 13/30 from human and 8/12 from cattle. Whole Genome Sequencing (WGS) was carried out at the facilities of Kenya Medical Research Institute-Wellcome trust, Kilifi, to determine the phylogenomic changes, virulence and resistant genes. RESULTS: At household level, the genomes from both human and animals clustered away from one another except for one instance where two human isolates from the same household clustered together. However, 67% of the E. coli isolated from cattle were closely related to those found in humans. The E. coli isolates were assigned to eight different phylogroups: A, B1, B2, Cladel, D, E, F and G, with a majority being assigned to phylogroup A; while most of the animal isolates were assigned to phylogroup B1. The carriage of multiple AMR genes was higher from the E. coli population from humans than those from cattle. Among these were Beta-lactamase; blaOXA-1: Class D beta-lactamases; blaTEM-1, blaTEM-235: Beta-lactamase; catA1: chloramphenicol acetyl transferase; cmlA1: chloramphenicol efflux transporter; dfrA1, dfrA12, dfrA14, dfrA15, dfrA17, dfrA5, dfrA7, dfrA8: macrolide phosphotransferase; oqxB11: RND efflux pump conferring resistance to fluoroquinolone; qacL, qacEdelta1: quinolone efflux pump; qnrS1: quinolone resistance gene; sul1, sul2, sul3: sulfonamide resistant; tet(A), tet(B): tetracycline efflux pump. A high variation of virulence genes was registered among the E. coli genomes from humans than those of cattle origin. CONCLUSION: From the analysis of the core genome and phenotypic resistance, this study has demonstrated that the E. coli of human origin and those of cattle origin may have a common ancestry. Limited sharing of virulence genes presents a challenge to the notion that AMR in humans is as a result of antibiotic use in the farm and distorts the picture of the directionality of transmission of AMR at a human-animal interface and presents a task of exploring alternative routes of transmission of AMR.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Escherichia coli , Filogenia , Factores de Virulencia/genética , Animales , Antibacterianos/farmacología , Bovinos , Estudios Transversales , Escherichia coli/genética , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/transmisión , Proteínas de Escherichia coli/genética , Genes Bacterianos , Genoma Bacteriano , Humanos , Pruebas de Sensibilidad Microbiana , Uganda , Secuenciación Completa del Genoma , beta-Lactamasas/genética
9.
PLoS One ; 14(12): e0225545, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31830061

RESUMEN

BACKGROUND: Although the significance of the human vaginal microbiome for health and disease is increasingly acknowledged, there is paucity of data on the differences in the composition of the vaginal microbiome upon infection with different sexually transmitted pathogens. METHOD: The composition of the vaginal bacterial community of women with Trichomonas vaginalis (TV, N = 18) was compared to that of women with Chlamydia trachomatis (CT, N = 14), and to that of controls (N = 21) (women negative for TV, CT and bacterial vaginosis). The vaginal bacterial composition was determined using high throughput sequencing with the Ion 16S metagenomics kit of the variable regions 2, 4 and 8 of the bacterial 16S ribosomal RNA gene from the vaginal swab DNA extract of the women. QIIME and R package "Phyloseq" were used to assess the α- and ß-diversity and absolute abundance of the 16S rRNA gene per sample in the three groups. Differences in taxa at various levels were determined using the independent T-test. RESULTS: A total of 545 operational taxonomic units (OTUs) were identified in all the three groups of which 488 occurred in all three groups (core OTUs). Bacterial α-diversity, by both Simpson's and Shannon's indices, was significantly higher, (p = 0.056) and (p = 0.001) respectively, among women with either TV or CT than among controls (mean α-diversity TV-infected > CT-infected > Controls). At the genus level, women infected with TV had a significantly (p < 0.01) higher abundance of Parvimonas and Prevotella species compared to both controls and CT-infected women, whereas women infected with CT had a significantly (p < 0.05) higher abundance of Anaerococcus, Collinsella, Corynebacterium and Dialister. CONCLUSION: The vaginal microbiomes of TV and CT-infected women were markedly different from each other and from women without TV and CT. Future studies should determine whether the altered microbiomes are merely markers of disease, or whether they actively contribute to the pathology of the two genital infections.


Asunto(s)
Infecciones por Chlamydia/microbiología , Microbiota/inmunología , Complicaciones Infecciosas del Embarazo/microbiología , Vaginitis por Trichomonas/microbiología , Vagina/microbiología , Adolescente , Adulto , Infecciones por Chlamydia/inmunología , Chlamydia trachomatis/genética , Chlamydia trachomatis/inmunología , Chlamydia trachomatis/aislamiento & purificación , ADN Bacteriano/aislamiento & purificación , Femenino , Humanos , Microbiota/genética , Embarazo , Complicaciones Infecciosas del Embarazo/inmunología , ARN Ribosómico 16S/genética , Vaginitis por Trichomonas/inmunología , Trichomonas vaginalis/genética , Trichomonas vaginalis/inmunología , Trichomonas vaginalis/aislamiento & purificación , Adulto Joven
10.
PLoS One ; 14(10): e0221285, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31585459

RESUMEN

Insect damage on trees can severely affect the quality of timber, reduce the fecundity of the host and render it susceptible to fungal infestation and disease. Such pathology weakens or eventually kills the host. Infestation by two insect woodborer species (a moth and a beetle) is causing mortality of Sonneratia alba, a wide-ranging pioneer mangrove species of the Indo-Pacific. Establishing the infestation mechanism of the two insect woodborer species is an initial and essential step towards understanding their ecological role in the mangroves and in determining sustainable management priorities and options. Our main objectives were to investigate the infestation mechanism employed by the two insect woodborers which infest S. alba trees, to establish the occurrence of secondary infestation by endophytic fungi in the infested S. alba branches, and to explore a control management option to the woodborer infestation. We conducted an external inspection of infested branches in two large embayments in Kenya, Gazi Bay and Mida Creek, and by splitting infested branches we determined the respective internal infestation mechanisms. Infested wood samples from Gazi Bay and Mida Creek were incubated at 28±1°C for 3-5 days to establish the presence of fungi. A survey was conducted in both Gazi Bay and Mida Creek to ascertain the presence of ants on S. alba. The infestation characteristics of the two insect woodborer species were different. It took 6-8 months for the beetle to kill a branch of 150 cm-200 cm long. For the moth to kill a branch, it depended upon several factors including the contribution by multiple species, other than the moth infestation alone. A total of 15 endophytic fungal species were identified. Two ant species Oecophylla longipoda and a Pheidole sp. inhabited 62% and 69% respectively of sampled S. alba trees in Gazi Bay whereas only Pheidole sp. inhabited 17% of the sampled S. alba trees in Mida Creek. In summary, we have documented the time it takes each woodborer species to kill a branch, the infestation mechanism of the two insect woodborers, and we hypothesized on the role of two ant species. The presence of several different fungal species was ascertained, and we discussed their possible role in the infested wood. Our results cannot unambiguously associate the woodborers and identified fungi. We recommend further studies to investigate the presence or absence, and if present, the nature of fungi in the gut of the woodborers.


Asunto(s)
Escarabajos/fisiología , Lythraceae/parasitología , Modelos Biológicos , Mariposas Nocturnas/fisiología , Enfermedades de las Plantas/parasitología , Humedales , Animales , Kenia
11.
Infect Immun ; 76(2): 685-94, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18070892

RESUMEN

Immunity against the bovine intracellular protozoan parasite Theileria parva has been shown to be mediated by CD8 T cells. Six antigens targeted by CD8 T cells from T. parva-immune cattle of different major histocompatibility complex (MHC) genotypes have been identified, raising the prospect of developing a subunit vaccine. To facilitate further dissection of the specificity of protective CD8 T-cell responses and to assist in the assessment of responses to vaccination, we set out to identify the epitopes recognized in these T. parva antigens and their MHC restriction elements. Nine epitopes in six T. parva antigens, together with their respective MHC restriction elements, were successfully identified. Five of the cytotoxic-T-lymphocyte epitopes were found to be restricted by products of previously described alleles, and four were restricted by four novel restriction elements. Analyses of CD8 T-cell responses to five of the epitopes in groups of cattle carrying the defined restriction elements and immunized with live parasites demonstrated that, with one exception, the epitopes were consistently recognized by animals of the respective genotypes. The analysis of responses was extended to animals immunized with multiple antigens delivered in separate vaccine constructs. Specific CD8 T-cell responses were detected in 19 of 24 immunized cattle. All responder cattle mounted responses specific for antigens for which they carried an identified restriction element. By contrast, only 8 of 19 responder cattle displayed a response to antigens for which they did not carry an identified restriction element. These data demonstrate that the identified antigens are inherently dominant in animals with the corresponding MHC genotypes.


Asunto(s)
Antígenos de Protozoos/inmunología , Linfocitos T CD8-positivos/inmunología , Theileria parva/inmunología , Animales , Bovinos , Mapeo Epitopo , Epítopos de Linfocito T/inmunología , Femenino , Antígenos de Histocompatibilidad Clase I/genética , Epítopos Inmunodominantes/inmunología , Masculino , Datos de Secuencia Molecular , Análisis de Secuencia de ADN
12.
Microbes Infect ; 10(5): 462-70, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18468471

RESUMEN

Rab genes encode a subgroup of small GTP-binding proteins within the ras super-family that regulate targeting and fusion of transport vesicles within the secretory and endocytic pathways. These genes are of particular interest in the protozoan phylum Apicomplexa, since a family of Rab GTPases has been described for Plasmodium and most putative secretory pathway proteins in Apicomplexa have conventional predicted signal peptides. Moreover, peptide motifs have now been identified within a large number of secreted Plasmodium proteins that direct their targeting to the red blood cell cytosol, the apicoplast, the food vacuole and Maurer's clefs; in contrast, motifs that direct proteins to secretory organelles (rhoptries, micronemes and microspheres) have yet to be defined. The nature of the vesicle in which these proteins are transported to their destinations remains unknown and morphological structures equivalent to the endoplasmic reticulum and trans-Golgi stacks typical of other eukaryotes cannot be visualised in Apicomplexa. Since Rab GTPases regulate vesicular traffic in all eukaryotes, and this traffic in intracellular parasites could regulate import of nutrient and drugs and export of antigens, host cell modulatory proteins and lactate we compare and contrast here the Rab families of Apicomplexa.


Asunto(s)
Genoma de Protozoos , Plasmodium falciparum/genética , Theileria/genética , Proteínas de Unión al GTP rab/genética , Animales , ADN Protozoario/análisis , Bases de Datos de Ácidos Nucleicos , Perfilación de la Expresión Génica , Orden Génico , Genes Protozoarios , Genómica , Malaria/parasitología , Familia de Multigenes , Filogenia , Homología de Secuencia de Ácido Nucleico , Linfocitos T/parasitología
14.
Nucleic Acids Res ; 33(17): 5503-11, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16186131

RESUMEN

Massively parallel signature sequencing (MPSS) was used to analyze the transcriptome of the intracellular protozoan Theileria parva. In total 1,095,000, 20 bp sequences representing 4371 different signatures were generated from T.parva schizonts. Reproducible signatures were identified within 73% of potentially detectable predicted genes and 83% had signatures in at least one MPSS cycle. A predicted leader peptide was detected on 405 expressed genes. The quantitative range of signatures was 4-52,256 transcripts per million (t.p.m.). Rare transcripts (<50 t.p.m.) were detected from 36% of genes. Sequence signatures approximated a lognormal distribution, as in microarray. Transcripts were widely distributed throughout the genome, although only 47% of 138 telomere-associated open reading frames exhibited signatures. Antisense signatures comprised 13.8% of the total, comparable with Plasmodium. Eighty five predicted genes with antisense signatures lacked a sense signature. Antisense transcripts were independently amplified from schizont cDNA and verified by sequencing. The MPSS transcripts per million for seven genes encoding schizont antigens recognized by bovine CD8 T cells varied 1000-fold. There was concordance between transcription and protein expression for heat shock proteins that were very highly expressed according to MPSS and proteomics. The data suggests a low level of baseline transcription from the majority of protein-coding genes.


Asunto(s)
Genoma de Protozoos , Genómica/métodos , ARN Protozoario/biosíntesis , Theileria parva/genética , Animales , Sistemas de Lectura Abierta , Proteínas Protozoarias/biosíntesis , Proteínas Protozoarias/genética , ARN sin Sentido/biosíntesis , ARN sin Sentido/química , ARN Protozoario/análisis , ARN Protozoario/química , Análisis de Secuencia de ARN , Telómero/química , Theileria parva/crecimiento & desarrollo , Theileria parva/metabolismo , Activación Transcripcional
15.
Wellcome Open Res ; 2: 29, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28944299

RESUMEN

Background. Malaria control, and finally malaria elimination, requires the identification and targeting of residual foci or hotspots of transmission. However, the level of parasite mixing within and between geographical locations is likely to impact the effectiveness and durability of control interventions and thus should be taken into consideration when developing control programs. Methods. In order to determine the geographic-genetic patterns of Plasmodium falciparum parasite populations at a sub-national level in Kenya, we used the Sequenom platform to genotype 111 genome-wide distributed single nucleotide polymorphic (SNP) positions in 2486 isolates collected from children in 95 primary schools in western Kenya. We analysed these parasite genotypes for genetic structure using principal component analysis and assessed local and global clustering using statistical measures of spatial autocorrelation. We further examined the region for spatial barriers to parasite movement as well as directionality in the patterns of parasite movement. Results. We found no evidence of population structure and little evidence of spatial autocorrelation of parasite genotypes (correlation coefficients <0.03 among parasite pairs in distance classes of 1km, 2km and 5km; p value<0.01). An analysis of the geographical distribution of allele frequencies showed weak evidence of variation in distribution of alleles, with clusters representing a higher than expected number of samples with the major allele being identified for 5 SNPs. Furthermore, we found no evidence of the existence of spatial barriers to parasite movement within the region, but observed directional movement of parasites among schools in two separate sections of the region studied. Conclusions. Our findings illustrate a pattern of high parasite mixing within the study region. If this mixing is due to rapid gene flow, then "one-off" targeted interventions may not be currently effective at the sub-national scale in Western Kenya, due to the high parasite movement that is likely to lead to re-introduction of infection from surrounding regions. However repeated targeted interventions may reduce transmission in the surrounding regions.

16.
Wellcome Open Res ; 2: 10, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28612053

RESUMEN

Background: The first models of malaria transmission assumed a completely mixed and homogeneous population of parasites. Recent models include spatial heterogeneity and variably mixed populations. However, there are few empiric estimates of parasite mixing with which to parametize such models. Methods: Here we genotype 276 single nucleotide polymorphisms (SNPs) in 5199 P. falciparum isolates from two Kenyan sites (Kilifi county and Rachuonyo South district) and one Gambian site (Kombo coastal districts) to determine the spatio-temporal extent of parasite mixing, and use Principal Component Analysis (PCA) and linear regression to examine the relationship between genetic relatedness and distance in space and time for parasite pairs. Results: Using 107, 177 and 82 SNPs that were successfully genotyped in 133, 1602, and 1034 parasite isolates from The Gambia, Kilifi and Rachuonyo South district, respectively, we show that there are no discrete geographically restricted parasite sub-populations, but instead we see a diffuse spatio-temporal structure to parasite genotypes. Genetic relatedness of sample pairs is predicted by relatedness in space and time. Conclusions: Our findings suggest that targeted malaria control will benefit the surrounding community, but unfortunately also that emerging drug resistance will spread rapidly through the population.

18.
PLoS One ; 11(7): e0159437, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27454301

RESUMEN

Finger millet is an important cereal crop in eastern Africa and southern India with excellent grain storage quality and unique ability to thrive in extreme environmental conditions. Since negligible attention has been paid to improving this crop to date, the current study used Next Generation Sequencing (NGS) technologies to develop both Simple Sequence Repeat (SSR) and Single Nucleotide Polymorphism (SNP) markers. Genomic DNA from cultivated finger millet genotypes KNE755 and KNE796 was sequenced using both Roche 454 and Illumina technologies. Non-organelle sequencing reads were assembled into 207 Mbp representing approximately 13% of the finger millet genome. We identified 10,327 SSRs and 23,285 non-homeologous SNPs and tested 101 of each for polymorphism across a diverse set of wild and cultivated finger millet germplasm. For the 49 polymorphic SSRs, the mean polymorphism information content (PIC) was 0.42, ranging from 0.16 to 0.77. We also validated 92 SNP markers, 80 of which were polymorphic with a mean PIC of 0.29 across 30 wild and 59 cultivated accessions. Seventy-six of the 80 SNPs were polymorphic across 30 wild germplasm with a mean PIC of 0.30 while only 22 of the SNP markers showed polymorphism among the 59 cultivated accessions with an average PIC value of 0.15. Genetic diversity analysis using the polymorphic SNP markers revealed two major clusters; one of wild and another of cultivated accessions. Detailed STRUCTURE analysis confirmed this grouping pattern and further revealed 2 sub-populations within wild E. coracana subsp. africana. Both STRUCTURE and genetic diversity analysis assisted with the correct identification of the new germplasm collections. These polymorphic SSR and SNP markers are a significant addition to the existing 82 published SSRs, especially with regard to the previously reported low polymorphism levels in finger millet. Our results also reveal an unexploited finger millet genetic resource that can be included in the regional breeding programs in order to efficiently optimize productivity.


Asunto(s)
Eleusine/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Repeticiones de Microsatélite , Polimorfismo de Nucleótido Simple , Biología Computacional/métodos , Minería de Datos , Bases de Datos Genéticas , Variación Genética , Genética de Población , Genotipo , Anotación de Secuencia Molecular , Filogenia , Reproducibilidad de los Resultados
19.
Genome Announc ; 1(4)2013 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-23868134

RESUMEN

Streptococcus agalactiae causes a range of clinical syndromes in camels (Camelus dromedarius). We report the genome sequences of two S. agalactiae isolates that induce abscesses in Kenyan camels. These genomes provide novel data on the composition of the S. agalactiae "pan genome" and reveal the presence of multiple genomic islands.

20.
Database (Oxford) ; 2011: bar015, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21546359

RESUMEN

We describe the development of TparvaDB, a comprehensive resource to facilitate research towards development of an East Coast fever vaccine, by providing an integrated user-friendly database of all genome and related data currently available for Theileria parva. TparvaDB is based on the Generic Model Organism Database (GMOD) platform. It contains a complete reference genome sequence, Expressed Sequence Tags (ESTs), Massively Parallel Signature Sequencing (MPSS) expression tag data and related information from both public and private repositories. The Artemis annotation workbench provides online annotation functionality. TparvaDB represents a resource that will underpin and promote ongoing East Coast fever vaccine development and biological research. Database URL: http://tparvadb.ilri.cgiar.org.


Asunto(s)
Bases de Datos Genéticas , Vacunas Antiprotozoos/inmunología , Theileria parva/genética , Theileria parva/inmunología , Etiquetas de Secuencia Expresada , Internet , Anotación de Secuencia Molecular , Interfaz Usuario-Computador
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA