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1.
J Neurovirol ; 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38713307

RESUMO

Despite antiretroviral therapy (ART), HIV persistence in the central nervous system (CNS) continues to cause a range of cognitive impairments in people living with HIV (PLWH). Upon disease progression, transmigrating CCR5-using T-cell tropic viruses are hypothesized to evolve into macrophage-tropic viruses in the CNS that can efficiently infect low CD4-expressing cells, such as microglia. We examined HIV-1 RNA concentration, co-receptor usage, and CSF compartmentalization in paired CSF and blood samples from 19 adults not on treatment. Full-length envelope CSF- and plasma-derived reporter viruses were generated from 3 subjects and phenotypically characterized in human primary CD4+ T-cells and primary microglia. Median HIV RNA levels were higher in plasma than in CSF (5.01 vs. 4.12 log10 cp/mL; p = 0.004), and coreceptor usage was mostly concordant for CCR5 across the paired samples (n = 17). Genetically compartmentalized CSF viral populations were detected in 2 subjects, one with and one without neurological symptoms. All viral clones could replicate in T-cells (R5 T cell-tropic). In addition, 3 CSF and 1 plasma patient-derived viral clones also had the capacity to replicate in microglia/macrophages and, therefore have an intermediate macrophage tropic phenotype. Overall, with this study, we demonstrate that in a subset of PLWH, plasma-derived viruses undergo genetic and phenotypic evolution within the CNS, indicating viral infection and replication in CNS cells. It remains to be studied whether the intermediate macrophage-tropic phenotype observed in primary microglia represents a midpoint in the evolution towards a macrophage-tropic phenotype that can efficiently replicate in microglial cells and propagate viral infection in the CNS.

2.
Pathogens ; 13(1)2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38251377

RESUMO

The pine pitch canker pathogen, Fusarium circinatum, is globally regarded as one of the most important threats to commercial pine-based forestry. Although genome sequences of this fungus are available, these remain highly fragmented or structurally ill-defined. Our overall goal was to provide high-quality assemblies for two notable strains of F. circinatum, and to characterize these in terms of coding content, repetitiveness and the position of telomeres and centromeres. For this purpose, we used Oxford Nanopore Technologies MinION long-read sequences, as well as Illumina short sequence reads. By leveraging the genomic synteny inherent to F. circinatum and its close relatives, these sequence reads were assembled to chromosome level, where contiguous sequences mostly spanned from telomere to telomere. Comparative analyses unveiled remarkable variability in the twelfth and smallest chromosome, which is known to be dispensable. It presented a striking length polymorphism, with one strain lacking substantial portions from the chromosome's distal and proximal regions. These regions, characterized by a lower gene density, G+C content and an increased prevalence of repetitive elements, contrast starkly with the syntenic segments of the chromosome, as well as with the core chromosomes. We propose that these unusual regions might have arisen or expanded due to the presence of transposable elements. A comparison of the overall chromosome structure revealed that centromeric elements often underpin intrachromosomal differences between F. circinatum strains, especially at chromosomal breakpoints. This suggests a potential role for centromeres in shaping the chromosomal architecture of F. circinatum and its relatives. The publicly available genome data generated here, together with the detailed metadata provided, represent essential resources for future studies of this important plant pathogen.

3.
medRxiv ; 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38293032

RESUMO

Chronic hepatitis B virus (HBV) infection remains a significant public health concern, particularly in Africa, where there is a substantial burden. HBV is an enveloped virus, with isolates being classified into ten phylogenetically distinct genotypes (A - J) determined based on full-genome sequence data or reverse hybridization-based diagnostic tests. In practice, limitations are noted in that diagnostic sequencing, generally using Sanger sequencing, tends to focus only on the S-gene, yielding little or no information on intra-patient HBV genetic diversity with very low-frequency variants and reverse hybridization detects only known genotype-specific mutations. To resolve these limitations, we developed an Oxford Nanopore Technology (ONT)-based HBV genotyping protocol suitable for clinical virology, yielding complete HBV genome sequences and extensive data on intra-patient HBV diversity. Specifically, the protocol involves tiling-based PCR amplification of HBV sequences, library preparation using the ONT Rapid Barcoding Kit, ONT GridION sequencing, genotyping using Genome Detective software, recombination analysis using jpHMM and RDP5 software, and drug resistance profiling using Geno2pheno software. We prove the utility of our protocol by efficiently generating and characterizing high-quality near full-length HBV genomes from 148 left-over diagnostic Hepatitis B patient samples obtained in the Western Cape province of South Africa, providing valuable insights into the genetic diversity and epidemiology of HBV in this region of the world.

4.
Influenza Other Respir Viruses ; 17(9): e13198, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37744993

RESUMO

Background: In Angola, COVID-19 cases have been reported in all provinces, resulting in >105,000 cases and >1900 deaths. However, no detailed genomic surveillance into the introduction and spread of the SARS-CoV-2 virus has been conducted in Angola. We aimed to investigate the emergence and epidemic progression during the peak of the COVID-19 pandemic in Angola. Methods: We generated 1210 whole-genome SARS-CoV-2 sequences, contributing West African data to the global context, that were phylogenetically compared against global strains. Virus movement events were inferred using ancestral state reconstruction. Results: The epidemic in Angola was marked by four distinct waves of infection, dominated by 12 virus lineages, including VOCs, VOIs, and the VUM C.16, which was unique to South-Western Africa and circulated for an extended period within the region. Virus exchanges occurred between Angola and its neighboring countries, and strong links with Brazil and Portugal reflected the historical and cultural ties shared between these countries. The first case likely originated from southern Africa. Conclusion: A lack of a robust genome surveillance network and strong dependence on out-of-country sequencing limit real-time data generation to achieve timely disease outbreak responses, which remains of the utmost importance to mitigate future disease outbreaks in Angola.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiologia , Angola/epidemiologia , Epidemiologia Molecular , Pandemias
5.
Genes (Basel) ; 14(3)2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36980977

RESUMO

Ethiopia is the second most populous country in Africa and the sixth most affected by COVID-19 on the continent. Despite having experienced five infection waves, >499,000 cases, and ~7500 COVID-19-related deaths as of January 2023, there is still no detailed genomic epidemiological report on the introduction and spread of SARS-CoV-2 in Ethiopia. In this study, we reconstructed and elucidated the COVID-19 epidemic dynamics. Specifically, we investigated the introduction, local transmission, ongoing evolution, and spread of SARS-CoV-2 during the first four infection waves using 353 high-quality near-whole genomes sampled in Ethiopia. Our results show that whereas viral introductions seeded the first wave, subsequent waves were seeded by local transmission. The B.1.480 lineage emerged in the first wave and notably remained in circulation even after the emergence of the Alpha variant. The B.1.480 was outcompeted by the Delta variant. Notably, Ethiopia's lack of local sequencing capacity was further limited by sporadic, uneven, and insufficient sampling that limited the incorporation of genomic epidemiology in the epidemic public health response in Ethiopia. These results highlight Ethiopia's role in SARS-CoV-2 dissemination and the urgent need for balanced, near-real-time genomic sequencing.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Epidemiologia Molecular , SARS-CoV-2/genética , Etiópia/epidemiologia , COVID-19/epidemiologia , COVID-19/genética
6.
PLOS Glob Public Health ; 3(3): e0001593, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36963096

RESUMO

Mozambique reported the first case of coronavirus disease 2019 (COVID-19) in March 2020 and it has since spread to all provinces in the country. To investigate the introductions and spread of SARS-CoV-2 in Mozambique, 1 142 whole genome sequences sampled within Mozambique were phylogenetically analyzed against a globally representative set, reflecting the first 25 months of the epidemic. The epidemic in the country was marked by four waves of infection, the first associated with B.1 ancestral lineages, while the Beta, Delta, and Omicron Variants of Concern (VOCs) were responsible for most infections and deaths during the second, third, and fourth waves. Large-scale viral exchanges occurred during the latter three waves and were largely attributed to southern African origins. Not only did the country remain vulnerable to the introductions of new variants but these variants continued to evolve within the borders of the country. Due to the Mozambican health system already under constraint, and paucity of data in Mozambique, there is a need to continue to strengthen and support genomic surveillance in the country as VOCs and Variants of interests (VOIs) are often reported from the southern African region.

7.
J Fungi (Basel) ; 8(11)2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36422035

RESUMO

Fusarium circinatum is an economically important pathogen of pine and resides in the Fusarium fujikuroi species complex. Here we investigated the molecular processes underlying growth in F. circinatum by exploring the association between growth and the nutritional environment provided by the pine host. For this purpose, we subjected a mapping population consisting of F. circinatum X F. temperatum hybrid progeny to an analysis of growth rate on a pine-tissue derived medium. These data, together with the available genetic linkage map for F. circinatum, were then used to identify Quantitative Trait Loci (QTLs) associated with growth. The single significant QTL identified was then characterized using the available genome sequences for the hybrid progeny's parental isolates. This revealed that the QTL localized to two non-homologous regions in the F. circinatum and F. temperatum genomes. For one of these, the F. circinatum parent contained a two-gene deletion relative to the F. temperatum parent. For the other region, the two parental isolates encoded different protein products. Analysis of repeats, G+C content, and repeat-induced point (RIP) mutations further suggested a retrotransposon origin for the two-gene deletion in F. circinatum. Nevertheless, subsequent genome and PCR-based analyses showed that both regions were similarly polymorphic within a collection of diverse F. circinatum. However, we observed no clear correlation between the respective polymorphism patterns and growth rate in culture. These findings support the notion that growth is a complex multilocus trait and raise the possibility that the identified QTL contains multiple small-effect QTLs, of which some might be dependent on the genetic backgrounds. This study improved our current knowledge of the genetic determinants of vegetative growth in F. circinatum and provided an important foundation for determining the genes and processes underpinning its ability to colonize its host environment.

8.
J Public Health Afr ; 13(3): 2201, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36277943

RESUMO

Background: As evidence supports task-shifting approaches to reduce the global mental health treatment gap, counselor competency evaluation measures are critical to ensure evidence-based therapies are administered with quality and fidelity. Objective: This article describes a training technique for evaluating lay counselors' competency for mental health lay practitioners without rating scale experience. Methods: Mental health practitioners were trained to give the Enhancing Assessment of Common Therapeutic Factors (ENACT) test to assess counselor proficiency in delivering the Common Elements Treatment Approach (CETA) in-person and over the phone using standardized video and audio recordings. A two-day in-person training was followed by a one-day remote training session. Training includes a review of item scales through didactic instructions, active learning by witnessing and scoring role-plays, peer interactions, and trainer observation and feedback. The trainees rated video and audio recordings, and ICC values were calculated. Results: The training technique presented in this research helped achieve high counselor competency scores among lay providers with no prior experience using rating scales. ICC rated both trainings satisfactory to exceptional (ICC: .71 - .89). Conclusions: Raters with no past experience with rating scales can achieve high consistency when rating counselor competency through training. Effective rater training should include didactic learning, practical learning with trainer observation and feedback, and video and audio recordings to assess consistency.

9.
J Fungi (Basel) ; 8(7)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35887414

RESUMO

Fusarium circinatum is an important global pathogen of pine trees. Genome plasticity has been observed in different isolates of the fungus, but no genome comparisons are available. To address this gap, we sequenced and assembled to chromosome level five isolates of F. circinatum. These genomes were analysed together with previously published genomes of F. circinatum isolates, FSP34 and KS17. Multi-sample variant calling identified a total of 461,683 micro variants (SNPs and small indels) and a total of 1828 macro structural variants of which 1717 were copy number variants and 111 were inversions. The variant density was higher on the sub-telomeric regions of chromosomes. Variant annotation revealed that genes involved in transcription, transport, metabolism and transmembrane proteins were overrepresented in gene sets that were affected by high impact variants. A core genome representing genomic elements that were conserved in all the isolates and a non-redundant pangenome representing all genomic elements is presented. Whole genome alignments showed that an average of 93% of the genomic elements were present in all isolates. The results of this study reveal that some genomic elements are not conserved within the isolates and some variants are high impact. The described genome-scale variations will help to inform novel disease management strategies against the pathogen.

10.
Soc Sci Med ; 268: 113458, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33126100

RESUMO

RATIONALE: Despite well-established associations between alcohol use, poor mental health, and intimate partner violence (IPV), limited attention has been given to how psychological and behavioral interventions might prevent or treat IPV in low- and middle-income countries. OBJECTIVE: In a recent randomized controlled trial in Lusaka, Zambia, transdiagnostic cognitive-behavioral psychotherapy (the Common Elements Treatment Approach; CETA) demonstrated significant treatment effects on men's alcohol use and women's IPV victimization in couples in which hazardous alcohol use by the male and intimate partner violence against the female was reported. In this study, we sought to gain a more in-depth understanding of mechanisms of behavior change among CETA participants. METHODS: We conducted 50 semi-structured in-depth interviews and 4 focus groups with a purposeful sample of adult men and women who received CETA between April and October 2018. Transcripts were analyzed using an inductive constant comparison approach by a team of US- and Zambia-based coders. RESULTS: Participants described interrelated mechanisms of change, including the use of safety strategies to not only avoid or prevent conflict but also to control anger; reductions in alcohol use that directly and indirectly reduced conflict; and, positive changes in trust and understanding of one's self and their partner. Several overarching themes also emerged from the data: how gender norms shaped participants' understanding of violence reduction strategies; the role of household economics in cycles of alcohol and violence; and, deleterious and virtuous intercouple dynamics that could perpetuate or diminish violence. CONCLUSIONS: Results suggest important avenues for future research including the potential for combining CETA with poverty reduction or gender norms focused interventions and for incorporating cognitivebehavioral skills into community level interventions.


Assuntos
Violência por Parceiro Íntimo , Adulto , Consumo de Bebidas Alcoólicas , Características da Família , Feminino , Humanos , Renda , Violência por Parceiro Íntimo/prevenção & controle , Masculino , Zâmbia
11.
PLoS Med ; 17(4): e1003056, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32302308

RESUMO

BACKGROUND: Both intimate partner violence (IPV) and alcohol misuse are highly prevalent, and partner alcohol misuse is a significant contributor to women's risk for IPV. There are few evidence-based interventions to address these problems in low- and middle-income countries (LMICs). We evaluated the effectiveness of an evidence-based, multi-problem, flexible, transdiagnostic intervention, the Common Elements Treatment Approach (CETA) in reducing (a) women's experience of IPV and (b) their male partner's alcohol misuse among couples in urban Zambia. METHODS AND FINDINGS: This was a single-blind, parallel-assignment randomized controlled trial in Lusaka, Zambia. Women who reported moderate or higher levels of IPV and their male partners with hazardous alcohol use were enrolled as a couple and randomized to CETA or treatment as usual plus safety checks (TAU-Plus). The primary outcome, IPV, was assessed by the Severity of Violence Against Women Scale (SVAWS) physical/sexual violence subscale, and the secondary outcome, male alcohol misuse, by the Alcohol Use Disorders Identification Test (AUDIT). Assessors were blinded. Analyses were intent-to-treat. Primary outcome assessments were planned at post-treatment, 12 months post-baseline, and 24 months post-baseline. Enrollment was conducted between May 23, 2016, and December 17, 2016. In total, 123 couples were randomized to CETA, 125 to TAU-Plus. The majority of female (66%) and a plurality of male (48%) participants were between 18 and 35 years of age. Mean reduction in IPV (via SVAWS subscale score) at 12 months post-baseline was statistically significantly greater among women who received CETA compared to women who received TAU-Plus (-8.2, 95% CI -14.9 to -1.5, p = 0.02, Cohen's d effect size = 0.49). Similarly, mean reduction in AUDIT score at 12 months post-baseline was statistically significantly greater among men who received CETA compared to men who received TAU (-4.5, 95% CI -6.9 to -2.2, p < 0.001, Cohen's d effect size = 0.43). The Data and Safety Monitoring Board recommended the trial be stopped early due to treatment effectiveness following the 12-month post-baseline assessment, and CETA was offered to control participants. Limitations of the trial included the lack of a true control condition (i.e., that received no intervention), self-reported outcomes that may be subject to social desirability bias, and low statistical power for secondary IPV outcomes. CONCLUSIONS: Results showed that CETA was more effective than TAU-Plus in reducing IPV and hazardous alcohol use among high-risk couples in Zambia. Future research and programming should include tertiary prevention approaches to IPV, such as CETA, rather than offering only community mobilization and primary prevention. TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov (NCT02790827).


Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Consumo de Bebidas Alcoólicas/terapia , Terapia Cognitivo-Comportamental/métodos , Violência por Parceiro Íntimo/prevenção & controle , Violência por Parceiro Íntimo/psicologia , Adolescente , Adulto , Idoso , Consumo de Bebidas Alcoólicas/epidemiologia , Alcoolismo/epidemiologia , Alcoolismo/psicologia , Alcoolismo/terapia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Método Simples-Cego , Resultado do Tratamento , Adulto Jovem , Zâmbia/epidemiologia
12.
Front Microbiol ; 11: 622368, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33597932

RESUMO

The Repeat-Induced Point (RIP) mutation pathway is a fungus-specific genome defense mechanism that mitigates the deleterious consequences of repeated genomic regions and transposable elements (TEs). RIP mutates targeted sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence and extent of RIP with a sliding-window approach. Using genome-wide RIP data and two sets of control groups, the association between RIP, TEs, and GC content were contrasted in organisms capable and incapable of RIP. Based on these data, we then set out to determine the extent and occurrence of RIP in 58 representatives of the Ascomycota. The findings were summarized by placing each of the fungi investigated in one of six categories based on the extent of genome-wide RIP. In silico RIP analyses, using a sliding-window approach with stringent RIP parameters, implemented simultaneously within the same genetic context, on high quality genome assemblies, yielded superior results in determining the genome-wide RIP among the Ascomycota. Most Ascomycota had RIP and these mutations were particularly widespread among classes of the Pezizomycotina, including the early diverging Orbiliomycetes and the Pezizomycetes. The most extreme cases of RIP were limited to representatives of the Dothideomycetes and Sordariomycetes. By contrast, the genomes of the Taphrinomycotina and Saccharomycotina contained no detectable evidence of RIP. Also, recent losses in RIP combined with controlled TE proliferation in the Pezizomycotina subphyla may promote substantial genome enlargement as well as the formation of sub-genomic compartments. These findings have broadened our understanding of the taxonomic range and extent of RIP in Ascomycota and how this pathway affects the genomes of fungi harboring it.

13.
Assessment ; 27(6): 1335-1348, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-29871499

RESUMO

There is a paucity of validated mental health measures for assessing psychological well-being among HIV-affected youth. We sought to explore the psychometric properties and validity of the Achenbach Youth Self-Report and Child Posttraumatic Stress Disorder Symptom Scale among orphans and vulnerable children (OVC) living in Lusaka, Zambia. These scales were administered to 210 OVC aged 13 to 17 years via audio computer-assisted self-interview. Confirmatory factor analysis was used to assess scale structure, Cronbach's alpha for internal consistency, and correlations between scales related to mental or psychosocial health for construct validity. A known-groups validation was conducted using local identifications of youth with and without significant psychosocial problems, and test-retest reliability was assessed. Scales exhibited good internal reliability (α > .80), adequate criterion validity (area under the curve > .70), and moderate test-retest reliability (.62-.68). Findings support the utility of these symptom scales for identifying OVC experiencing significant psychosocial problems in Zambia.


Assuntos
Crianças Órfãs , Transtornos de Estresse Pós-Traumáticos , Adolescente , Criança , Humanos , Psicometria , Reprodutibilidade dos Testes , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Inquéritos e Questionários , Zâmbia
14.
Pathogens ; 8(4)2019 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-31847413

RESUMO

The Repeat-Induced Point (RIP) mutation pathway is a fungal-specific genome defense mechanism that counteracts the deleterious effects of transposable elements. This pathway permanently mutates its target sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence of RIP in the pitch canker pathogen, Fusarium circinatum, and its close relatives in the Fusarium fujikuroi species complex (FFSC). Our results showed that the examined fungi all exhibited hallmarks of RIP, but that they differed in terms of the extent to which their genomes were affected by this pathway. RIP mutations constituted a large proportion of all the FFSC genomes, including both core and dispensable chromosomes, although the latter were generally more extensively affected by RIP. Large RIP-affected genomic regions were also much more gene sparse than the rest of the genome. Our data further showed that RIP-directed sequence diversification increased the variability between homologous regions of related species, and that RIP-affected regions can interfere with homologous recombination during meiosis, thereby contributing to post-mating segregation distortion. Taken together, these findings suggest that RIP can drive the independent divergence of chromosomes, alter chromosome architecture, and contribute to the divergence among F. circinatum and other members of this economically important group of fungi.

15.
PeerJ ; 7: e7447, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31523495

RESUMO

BACKGROUND: The RIPper (http://theripper.hawk.rocks) is a set of web-based tools designed for analyses of Repeat-Induced Point (RIP) mutations in the genome sequences of Ascomycota. The RIP pathway is a fungal genome defense mechanism that is aimed at identifying repeated and duplicated motifs, into which it then introduces cytosine to thymine transition mutations. RIP thus serves to deactivate and counteract the deleterious consequences of selfish or mobile DNA elements in fungal genomes. The occurrence, genetic context and frequency of RIP mutations are widely used to assess the activity of this pathway in genomic regions of interest. Here, we present a bioinformatics tool that is specifically fashioned to automate the investigation of changes in RIP product and substrate nucleotide frequencies in fungal genomes. RESULTS: We demonstrated the ability of The RIPper to detect the occurrence and extent of RIP mutations in known RIP affected sequences. Specifically, a sliding window approach was used to perform genome-wide RIP analysis on the genome assembly of Neurospora crassa. Additionally, fine-scale analysis with The RIPper showed that gene regions and transposable element sequences, previously determined to be affected by RIP, were indeed characterized by high frequencies of RIP mutations. Data generated using this software further showed that large proportions of the N. crassa genome constitutes RIP mutations with extensively affected regions displaying reduced GC content. The RIPper was further useful for investigating and visualizing changes in RIP mutations across the length of sequences of interest, allowing for fine-scale analyses. CONCLUSION: This software identified RIP targeted genomic regions and provided RIP statistics for an entire genome assembly, including the genomic proportion affected by RIP. Here, we present The RIPper as an efficient tool for genome-wide RIP analyses.

16.
Fungal Biol ; 123(5): 351-363, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31053324

RESUMO

The overall goal of this study was to determine whether the genome of an important plant pathogen in Africa, Ceratocystis albifundus, is structured into subgenomic compartments, and if so, to establish how these compartments are distributed across the genome. For this purpose, the publicly available genome of C. albifundus was complemented with the genome sequences for four additional isolates using the Illumina HiSeq platform. In addition, a reference genome for one of the individuals was assembled using both PacBio and Illumina HiSeq technologies. Our results showed a high degree of synteny between the five genomes, although several regions lacked detectable long-range synteny. These regions were associated with the presence of accessory genes, lower genetic similarity, variation in read-map depth, as well as transposable elements and genes associated with host-pathogen interactions (e.g. effectors and CAZymes). Such patterns are regarded as hallmarks of accelerated evolution, particularly of accessory subgenomic compartments in fungal pathogens. Our findings thus showed that the genome of C. albifundus is made-up of core and accessory subgenomic compartments, which is an important step towards characterizing its pangenome. This study also highlights the value of comparative genomics for understanding mechanisms that may underly and influence the biology and evolution of pathogens.


Assuntos
Ascomicetos/genética , Genoma Fúngico , Doenças das Plantas/microbiologia , Árvores/microbiologia , África , Biologia Computacional , Evolução Molecular , Ordem dos Genes , Variação Genética , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Sequências Repetitivas Dispersas , Sintenia
17.
PeerJ ; 7: e6698, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024760

RESUMO

With the increased availability of genome sequences for bacteria, it has become routine practice to construct genome-based phylogenies. These phylogenies have formed the basis for various taxonomic decisions, especially for resolving problematic relationships between taxa. Despite the popularity of concatenating shared genes to obtain well-supported phylogenies, various issues regarding this combined-evidence approach have been raised. These include the introduction of phylogenetic error into datasets, as well as incongruence due to organism-level evolutionary processes, particularly horizontal gene transfer and incomplete lineage sorting. Because of the huge effect that this could have on phylogenies, we evaluated the impact of phylogenetic conflict caused by organism-level evolutionary processes on the established species phylogeny for Pantoea, a member of the Enterobacterales. We explored the presence and distribution of phylogenetic conflict at the gene partition and nucleotide levels, by identifying putative inter-lineage recombination events that might have contributed to such conflict. Furthermore, we determined whether smaller, randomly constructed datasets had sufficient signal to reconstruct the current species tree hypothesis or if they would be overshadowed by phylogenetic incongruence. We found that no individual gene tree was fully congruent with the species phylogeny of Pantoea, although many of the expected nodes were supported by various individual genes across the genome. Evidence of recombination was found across all lineages within Pantoea, and provides support for organism-level evolutionary processes as a potential source of phylogenetic conflict. The phylogenetic signal from at least 70 random genes recovered robust, well-supported phylogenies for the backbone and most species relationships of Pantoea, and was unaffected by phylogenetic conflict within the dataset. Furthermore, despite providing limited resolution among taxa at the level of single gene trees, concatenated analyses of genes that were identified as having no signal resulted in a phylogeny that resembled the species phylogeny of Pantoea. This distribution of signal and noise across the genome presents the ideal situation for phylogenetic inference, as the topology from a ≥70-gene concatenated species phylogeny is not driven by single genes, and our data suggests that this finding may also hold true for smaller datasets. We thus argue that, by using a concatenation-based approach in phylogenomics, one can obtain robust phylogenies due to the synergistic effect of the combined signal obtained from multiple genes.

18.
Addict Behav Rep ; 8: 170-175, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30505923

RESUMO

INTRODUCTION: Although the World Health Organization (WHO) has recommended guidelines for the treatment of opioid dependence, there are myriad challenges to successfully implementing such guidelines in resource constrained settings, such as in low and middle-income countries (LMICs). To highlight these challenges, this paper presents a clinical case study of an adolescent study participant in a randomized controlled trial comparing two counseling programs in Lusaka, Zambia. CASE DESCRIPTION: This 15 year-old male reported smoking marijuana and heroin daily, and injecting heroin monthly (while needle sharing). The patient was linked to the only physician capable of treating heroin addiction in Zambia. The patient was placed on a 30-day detox regimen of Tramadol administered from home, as in-patient detox services are unavailable in Zambia. The patient experienced complications with out-patient detox, including a relapse that led to violent behavior and temporary incarceration. The patient's treatment regimen was altered to include Lorazepam, a mild sedative, and psychosocial counseling. After completing detox the client was prescribed Naltrexone for maintenance as Methadone is listed as a banned substance in Zambia, and Buprenorphine is not available and is cost prohibitive. CONCLUSIONS: Despite a considerable amount of time and resources expended to successfully treat the patient, the majority of WHO guidelines for opioid dependence treatment were not attainable within the Zambian context. Additional research into the effectiveness and implementation of evidence-based interventions for substance use in LMICs is warranted.

19.
IMA Fungus ; 9(1): 27-36, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30018870

RESUMO

Fusarium is a diverse assemblage that includes a large number of species of considerable medical and agricultural importance. Not surprisingly, whole genome sequences for many Fusarium species have been published or are in the process of being determined, the availability of which is invaluable for deciphering the genetic basis of key phenotypic traits. Here we investigated the distribution, genic composition, and evolutionary history of a locus potentially determining growth rate in the pitch canker pathogen F. circinatum. We found that the genomic region underlying this locus is highly conserved amongst F. circinatum and its close relatives, except for the presence of a 12 000 base pair insertion in all of the examined isolates of F. circinatum. This insertion encodes for five genes and our phylogenetic analyses revealed that each was most likely acquired through horizontal gene transfer from polyphyletic origins. Our data further showed that this region is located in a region low in G+C content and enriched for repetitive sequences and transposable elements, which is situated near the telomere of Chromosome 3 of F. circinatum. As have been shown for other fungi, these findings thus suggest that the emergence of the unique 12 000 bp region in F. circinatum is linked to the dynamic evolutionary processes associated with subtelomeres that, in turn, have been implicated in the ecological adaptation of fungal pathogens.

20.
IMA Fungus ; 9(1): 199-223, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30018880

RESUMO

Draft genomes of the species Annulohypoxylon stygium, Aspergillus mulundensis, Berkeleyomyces basicola (syn. Thielaviopsis basicola), Ceratocystis smalleyi, two Cercospora beticola strains, Coleophoma cylindrospora, Fusarium fracticaudum, Phialophora cf. hyalina and Morchella septimelata are presented. Both mating types (MAT1-1 and MAT1-2) of Cercospora beticola are included. Two strains of Coleophoma cylindrospora that produce sulfated homotyrosine echinocandin variants, FR209602, FR220897 and FR220899 are presented. The sequencing of Aspergillus mulundensis, Coleophoma cylindrospora and Phialophora cf. hyalina has enabled mapping of the gene clusters encoding the chemical diversity from the echinocandin pathways, providing data that reveals the complexity of secondary metabolism in these different species. Overall these genomes provide a valuable resource for understanding the molecular processes underlying pathogenicity (in some cases), biology and toxin production of these economically important fungi.

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