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1.
J Org Chem ; 88(2): 805-817, 2023 01 20.
Article in English | MEDLINE | ID: mdl-36602547

ABSTRACT

Two synthetic strategies employing phosphate tether-mediated one-pot sequential protocols for the total synthesis of the polyketide nonribosomal peptide macrolide, sanctolide A, and the formal synthesis of the (2S)-epimer of sanctolide A are reported. In this work, a phosphate tether-mediated one-pot sequential ring-closing metathesis/cross metathesis/substrate-controlled "H2"/tether removal approach was developed to accomplish the total synthesis of the natural product sanctolide A.


Subject(s)
Biological Products , Macrolides , Phosphates
2.
BMC Genomics ; 23(1): 699, 2022 Oct 10.
Article in English | MEDLINE | ID: mdl-36217140

ABSTRACT

BACKGROUND: One of the most complex prokaryotic organelles are magnetosomes, which are formed by magnetotactic bacteria as sensors for navigation in the Earth's magnetic field. In the alphaproteobacterium Magnetospirillum gryphiswaldense magnetosomes consist of chains of magnetite crystals (Fe3O4) that under microoxic to anoxic conditions are biomineralized within membrane vesicles. To form such an intricate structure, the transcription of > 30 specific structural genes clustered within the genomic magnetosome island (MAI) has to be coordinated with the expression of an as-yet unknown number of auxiliary genes encoding several generic metabolic functions. However, their global regulation and transcriptional organization in response to anoxic conditions most favorable for magnetite biomineralization are still unclear. RESULTS: Here, we compared transcriptional profiles of anaerobically grown magnetosome forming cells with those in which magnetosome biosynthesis has been suppressed by aerobic condition. Using whole transcriptome shotgun sequencing, we found that transcription of about 300 of the > 4300 genes was significantly enhanced during magnetosome formation. About 40 of the top upregulated genes are directly or indirectly linked to aerobic and anaerobic respiration (denitrification) or unknown functions. The mam and mms gene clusters, specifically controlling magnetosome biosynthesis, were highly transcribed, but constitutively expressed irrespective of the growth condition. By Cappable-sequencing, we show that the transcriptional complexity of both the MAI and the entire genome decreased under anaerobic conditions optimal for magnetosome formation. In addition, predominant promoter structures were highly similar to sigma factor σ70 dependent promoters in other Alphaproteobacteria. CONCLUSIONS: Our transcriptome-wide analysis revealed that magnetite biomineralization relies on a complex interplay between generic metabolic processes such as aerobic and anaerobic respiration, cellular redox control, and the biosynthesis of specific magnetosome structures. In addition, we provide insights into global regulatory features that have remained uncharacterized in the widely studied model organism M. gryphiswaldense, including a comprehensive dataset of newly annotated transcription start sites and genome-wide operon detection as a community resource (GEO Series accession number GSE197098).


Subject(s)
Magnetosomes , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Biomineralization/genetics , Ferrosoferric Oxide/analysis , Ferrosoferric Oxide/metabolism , Magnetosomes/genetics , Magnetosomes/metabolism , Magnetospirillum , Sigma Factor/genetics , Transcriptome
3.
mSystems ; 6(5): e0089321, 2021 Oct 26.
Article in English | MEDLINE | ID: mdl-34519524

ABSTRACT

Magnetosomes are complex membrane organelles synthesized by magnetotactic bacteria (MTB) for navigation in the Earth's magnetic field. In the alphaproteobacterium Magnetospirillum gryphiswaldense, all steps of magnetosome formation are tightly controlled by >30 specific genes arranged in several gene clusters. However, the transcriptional organization of the magnetosome gene clusters has remained poorly understood. Here, by applying Cappable-seq and whole-transcriptome shotgun RNA sequencing, we show that mamGFDCop and feoAB1op are transcribed as single transcriptional units, whereas multiple transcription start sites (TSS) are present in mms6op, mamXYop, and the long (>16 kb) mamABop. Using a bioluminescence reporter assay and promoter knockouts, we demonstrate that most of the identified TSS originate from biologically meaningful promoters which mediate production of multiple transcripts and are functionally relevant for proper magnetosome biosynthesis. In addition, we identified a strong promoter in a large intergenic region within mamXYop, which likely drives transcription of a noncoding RNA important for gene expression in this operon. In summary, our data suggest a more complex transcriptional architecture of the magnetosome operons than previously recognized, which is largely conserved in other magnetotactic Magnetospirillum species and, thus, is likely fundamental for magnetosome biosynthesis in these organisms. IMPORTANCE Magnetosomes have emerged as a model system to study prokaryotic organelles and a source of biocompatible magnetic nanoparticles for various biomedical applications. However, the lack of knowledge about the transcriptional organization of magnetosome gene clusters has severely impeded the engineering, manipulation, and transfer of this highly complex biosynthetic pathway into other organisms. Here, we provide a high-resolution image of the previously unappreciated transcriptional landscape of the magnetosome operons. Our findings are important for further unraveling the complex genetic framework of magnetosome biosynthesis. In addition, they will facilitate the rational reengineering of magnetic bacteria for improved bioproduction of tunable magnetic nanoparticles, as well as transplantation of magnetosome biosynthesis into foreign hosts by synthetic biology approaches. Overall, our study exemplifies how a genetically complex pathway is orchestrated at the transcriptional level to ensure the balanced expression of the numerous constituents required for the proper assembly of one of the most intricate prokaryotic organelles.

4.
mBio ; 12(3)2021 05 18.
Article in English | MEDLINE | ID: mdl-34006654

ABSTRACT

Genomic information from various magnetotactic bacteria suggested that besides their common ability to form magnetosomes, they potentially also represent a source of bioactive natural products. By using targeted deletion and transcriptional activation, we connected a large biosynthetic gene cluster (BGC) of the trans-acyltransferase polyketide synthase (trans-AT PKS) type to the biosynthesis of a novel polyketide in the alphaproteobacterium Magnetospirillum gryphiswaldense Structure elucidation by mass spectrometry and nuclear magnetic resonance spectroscopy (NMR) revealed that this secondary metabolite resembles sesbanimides, which were very recently reported from other taxa. However, sesbanimide R exhibits an additional arginine moiety the presence of which reconciles inconsistencies in the previously proposed sesbanimide biosynthesis pathway observed when comparing the chemical structure and the potential biochemistry encoded in the BGC. In contrast to the case with sesbanimides D, E, and F, we were able to assign the stereocenter of the arginine moiety experimentally and two of the remaining three stereocenters by predictive biosynthetic tools. Sesbanimide R displayed strong cytotoxic activity against several carcinoma cell lines.IMPORTANCE The findings of this study contribute a new secondary metabolite member to the glutarimide-containing polyketides. The determined structure of sesbanimide R correlates with its cytotoxic bioactivity, characteristic for members of this family. Sesbanimide R represents the first natural product isolated from magnetotactic bacteria and identifies this highly diverse group as a so-far-untapped source for the future discovery of novel secondary metabolites.


Subject(s)
Bacterial Proteins/biosynthesis , Biosynthetic Pathways , Magnetospirillum/metabolism , Polyketides/metabolism , Secondary Metabolism , Bacterial Proteins/classification , Bacterial Proteins/metabolism , Biological Products/metabolism , Phylogeny
5.
AIDS Behav ; 25(1): 58-67, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32830296

ABSTRACT

Persons living with HIV (PLWH) may be at increased risk for severe COVID-19-related illness. Our community-based participatory research partnership collected and analyzed semi-structured interview data to understand the early impact of the COVID-19 pandemic on a sample of racially/ethnically diverse gay, bisexual, and other men who have sex with men living with HIV. Fifteen cisgender men participated; their mean age was 28. Six participants were Black/African American, five were Spanish-speaking Latinx, and four were White. Seventeen themes emerged that were categorized into six domains: knowledge and perceptions of COVID-19; COVID-19 information sources and perceptions of trustworthiness; impact of COVID-19 on behaviors, health, and social determinants of health; and general COVID-19-related concerns. Interventions are needed to ensure that PLWH have updated information and adhere to medication regimens, and to reduce the impact of COVID-19 on social isolation, economic stability, healthcare access, and other social determinants of health within this vulnerable population.


RESUMEN: Las personas que viven con VIH (PLWH por sus siglas en inglés) pueden tener mayor riesgo de contraer serias enfermedades relacionadas con el COVID-19. Nuestra investigación participativa basada en la comunidad recopiló y analizó datos de entrevistas semiestructuradas para entender el impacto inicial de la pandemia COVID-19 en una muestra de hombres gay, bisexuales y otros hombres que tienen sexo con hombres de diversos grupos étnicos y raciales que viven con VIH. Participaron quince hombres cisgénero con un promedio de edad de 28 años. Seis participantes fueron negros/afroamericanos, cinco latinx hispanohablantes y cuatro blancos. Emergieron diecisiete temas que fueron categorizados en seis ámbitos: conocimiento y percepciones de COVID-19; fuentes de información sobre COVID-19 y percepciones de confiabilidad; impacto de COVID-19 en comportamientos, salud y determinantes sociales de la salud e inquietudes generales relacionadas con COVID-19. Se necesitan intervenciones para garantizar que las personas que viven con VIH tengan información actualizada y cumplan con adherirse a su régimen de tratamiento y reducir el impacto de COVID-19 en lo que respecta a aislamiento social, estabilidad económica, acceso a los servicios de atención médica y otros determinantes sociales de la salud en estas poblaciones vulnerables.


Subject(s)
Bisexuality/psychology , COVID-19/psychology , Homosexuality, Male/psychology , SARS-CoV-2 , Adult , Bisexuality/ethnology , Black People , COVID-19/epidemiology , Community-Based Participatory Research , HIV Infections/drug therapy , HIV Infections/epidemiology , HIV Infections/psychology , Health Knowledge, Attitudes, Practice , Hispanic or Latino , Homosexuality, Male/ethnology , Humans , Interviews as Topic , Male , North Carolina/epidemiology , Pandemics , Qualitative Research , White People
6.
Microb Cell Fact ; 19(1): 206, 2020 Nov 10.
Article in English | MEDLINE | ID: mdl-33168043

ABSTRACT

BACKGROUND: Magnetosomes produced by magnetotactic bacteria represent magnetic nanoparticles with unprecedented characteristics. However, their use in many biotechnological applications has so far been hampered by their challenging bioproduction at larger scales. RESULTS: Here, we developed an oxystat batch fermentation regime for microoxic cultivation of Magnetospirillum gryphiswaldense in a 3 L bioreactor. An automated cascade regulation enabled highly reproducible growth over a wide range of precisely controlled oxygen concentrations (1-95% of air saturation). In addition, consumption of lactate as the carbon source and nitrate as alternative electron acceptor were monitored during cultivation. While nitrate became growth limiting during anaerobic growth, lactate was the growth limiting factor during microoxic cultivation. Analysis of microoxic magnetosome biomineralization by cellular iron content, magnetic response, transmission electron microscopy and small-angle X-ray scattering revealed magnetosomal magnetite crystals were highly uniform in size and shape. CONCLUSION: The fermentation regime established in this study facilitates stable oxygen control during culturing of Magnetospirillum gryphiswaldense. Further scale-up seems feasible by combining the stable oxygen control with feeding strategies employed in previous studies. Results of this study will facilitate the highly reproducible laboratory-scale bioproduction of magnetosomes for a diverse range of future applications in the fields of biotechnology and biomedicine.


Subject(s)
Automation, Laboratory , Fermentation , Magnetosomes/metabolism , Magnetospirillum/growth & development , Magnetospirillum/metabolism , Oxygen/metabolism , Bacterial Proteins/metabolism , Bioreactors , Biotechnology , Carbon/metabolism , Ferrosoferric Oxide/metabolism
7.
Res Sq ; 2020 Aug 12.
Article in English | MEDLINE | ID: mdl-32818212

ABSTRACT

Persons living with HIV (PLWH) may be at increased risk for severe COVID-19-related illness. Our community-based participatory research partnership collected and analyzed semi-structured interview data to understand the early impact of the COVID-19 pandemic on a sample of racially/ethnically diverse gay, bisexual, and other men who have sex with men living with HIV. Fifteen cisgender men participated; their mean age was 28. Six participants were Black/African American, five were Spanish-speaking Latinx, and four were White. Seventeen themes emerged that were categorized into six domains: knowledge and perceptions of COVID-19; COVID-19 information sources and perceptions of trustworthiness; impact of COVID-19 on behaviors, health, and social determinants of health; and general COVID-19-related concerns. Interventions are needed to ensure that PLWH have updated information and adhere to medication regimens, and to reduce the impact of COVID-19 on social isolation, economic stability, healthcare access, and other social determinants of health within this vulnerable population.


Las personas que viven con VIH (PLWH por sus siglas en inglés) pueden tener mayor riesgo de contraer serias enfermedades relacionadas con el COVID-19. Nuestra investigación participativa basada en la comunidad recopiló y analizó datos de entrevistas semiestructuradas para entender el impacto inicial de la pandemia COVID-19 en una muestra de hombres gay, bisexuales y otros hombres que tienen sexo con hombres de diversos grupos étnicos y raciales que viven con VIH. Participaron quince hombres cisgénero con un promedio de edad de 28 años. Seis participantes fueron negros/afroamericanos, cinco latinx hispanohablantes y cuatro blancos. Emergieron diecisiete temas que fueron categorizados en seis ámbitos: conocimiento y percepciones de COVID-19; fuentes de información sobre COVID-19 y percepciones de confiabilidad; impacto de COVID-19 en comportamientos, salud y determinantes sociales de la salud e inquietudes generales relacionadas con COVID-19. Se necesitan intervenciones para garantizar que las personas que viven con VIH tengan información actualizada y cumplan con adherirse a su régimen de tratamiento y reducir el impacto de COVID-19 en lo que respecta a aislamiento social, estabilidad económica, acceso a los servicios de atención médica y otros determinantes sociales de la salud en estas poblaciones vulnerables.

8.
J Infect Dis ; 222(11): 1837-1842, 2020 11 09.
Article in English | MEDLINE | ID: mdl-32496516

ABSTRACT

AIDS Clinical Trials Group study A5308 found reduced T-cell activation and exhaustion in human immunodeficiency virus (HIV) controllers start antiretroviral therapy (ART). We further assessed HIV-specific T-cell responses and post-ART viral loads. Before ART, the 31% of participants with persistently undetectable viremia had more robust HIV-specific T-cell responses. During ART, significant decreases were observed in a broad range of T-cell responses. Eight controllers in A5308 and the Study of the Consequences of the Protease Inhibitor Era (SCOPE) cohort showed no viremia above the level of quantification in the first 12 weeks after ART discontinuation. ART significantly reduced HIV-specific T-cell responses in HIV controllers but did not adversely affect controller status after ART discontinuation.


Subject(s)
Anti-Retroviral Agents/therapeutic use , HIV Infections/drug therapy , HIV Infections/immunology , HIV-1/drug effects , T-Lymphocytes/immunology , Adult , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Cohort Studies , HIV Protease Inhibitors/therapeutic use , Humans , Lymphocyte Activation/drug effects , Viral Load/drug effects , Viremia/immunology
9.
Clin Infect Dis ; 70(8): 1636-1642, 2020 04 10.
Article in English | MEDLINE | ID: mdl-31131858

ABSTRACT

BACKGROUND: Despite low plasma human immunodeficiency virus (HIV) RNA, HIV controllers have evidence of viral replication and elevated inflammation. We assessed the effect of antiretroviral therapy (ART) on HIV suppression, immune activation, and quality of life (QoL). METHODS: A5308 was a prospective, open-label study of rilpivirine/emtricitabine/tenofovir disoproxil fumarate in ART-naive HIV controllers (N = 35), defined as having HIV RNA <500 copies/mL for ≥12 months. The primary outcome measured change in %CD38+HLA-DR+ CD8+ T cells. Residual plasma viremia was measured using the integrase single-copy assay. QoL was measured using the EQ-5D questionnaire. Outcomes were evaluated using repeated measures general estimating equations models. RESULTS: Before ART, HIV controllers with undetectable residual viremia <0.6 HIV-1 RNA copies/mL had higher CD4+ counts and lower levels of T-cell activation than those with detectable residual viremia. ART use was effective in further increasing the proportion of individuals with undetectable residual viremia (pre-ART vs after 24-48 weeks of ART: 19% vs 94%, P < .001). Significant declines were observed in the %CD38+HLA-DR+CD8+ T cells at 24-48 (-4.0%, P = .001) and 72-96 (-7.2%, P < .001) weeks after ART initiation. ART use resulted in decreases of several cellular markers of immune exhaustion and in a modest but significant improvement in self-reported QoL. There were no significant changes in CD4+ counts or HIV DNA. CONCLUSIONS: ART in HIV controllers reduces T-cell activation and improves markers of immune exhaustion. These results support the possible clinical benefits of ART in this population.


Subject(s)
HIV Infections , HIV-1 , CD4 Lymphocyte Count , CD4-Positive T-Lymphocytes , CD8-Positive T-Lymphocytes , HIV Infections/drug therapy , Humans , Lymphocyte Activation , Prospective Studies , Quality of Life , Viral Load
10.
Health Behav Res ; 2(3)2019.
Article in English | MEDLINE | ID: mdl-31799502

ABSTRACT

Gay, bisexual, and other men who have sex with men (GBMSM) have higher rates of HIV infection compared to the general population in the United States, and the infection rate is growing among Latinx GBMSM, compared to a decline in most other demographic subgroups. Uptake of pre-exposure prophylaxis (PrEP), a biomedical strategy designed to reduce HIV transmission, is very low among Latinx GBMSM. HIV testing is a critical first step in the HIV prevention and care continua. We analyzed data from a community-based sample of Latinx GBMSM in the southeastern United States to identify the most common HIV testing barriers and the factors associated with barriers. The five most commonly reported HIV testing barriers included not knowing where to get tested, not having health insurance, fear of being HIV positive, practicing safer sex and perceiving not needing to be tested, and not being recommended to get tested. Using multivariable logistic regression modeling, speaking only Spanish, being unemployed, and adhering to traditional notions of masculinity were associated with increased barriers to HIV testing. We recommend that interventions to increase HIV testing among Latinx GBMSM be in Spanish and use culturally congruent messaging, be accessible to those who are unemployed, and incorporate positive risk-reducing aspects of masculinity.

11.
Appl Environ Microbiol ; 85(24)2019 12 15.
Article in English | MEDLINE | ID: mdl-31604767

ABSTRACT

Magnetosomes are membrane-enveloped single-domain ferromagnetic nanoparticles enabling the navigation of magnetotactic bacteria along magnetic field lines. Strict control over each step of biomineralization generates particles of high crystallinity, strong magnetization, and remarkable uniformity in size and shape, which is particularly interesting for many biomedical and biotechnological applications. However, to understand the physicochemical processes involved in magnetite biomineralization, close and precise monitoring of particle production is required. Commonly used techniques, such as transmission electron microscopy (TEM) or Fe measurements, allow only for semiquantitative assessment of the magnetosome formation without routinely revealing quantitative structural information. In this study, lab-based small-angle X-ray scattering (SAXS) is explored as a means to monitor the different stages of magnetosome biogenesis in the model organism Magnetospirillum gryphiswaldense SAXS is evaluated as a quantitative stand-alone technique to analyze the size, shape, and arrangement of magnetosomes in cells cultivated under different growth conditions. By applying a simple and robust fitting procedure based on spheres aligned in linear chains, it is demonstrated that the SAXS data sets contain information on both the diameter of the inorganic crystal and the protein-rich magnetosome membrane. The analyses corroborate a narrow particle size distribution with an overall magnetosome radius of 19 nm in Magnetospirillum gryphiswaldense Furthermore, the averaged distance between individual magnetosomes is determined, revealing a chain-like particle arrangement with a center-to-center distance of 53 nm. Overall, these data demonstrate that SAXS can be used as a novel stand-alone technique allowing for the at-line monitoring of magnetosome biosynthesis, thereby providing accurate information on the particle nanostructure.IMPORTANCE This study explores lab-based small-angle X-ray scattering (SAXS) as a novel quantitative stand-alone technique to monitor the size, shape, and arrangement of magnetosomes during different stages of particle biogenesis in the model organism Magnetospirillum gryphiswaldense The SAXS data sets contain volume-averaged, statistically accurate information on both the diameter of the inorganic nanocrystal and the enveloping protein-rich magnetosome membrane. As a robust and nondestructive in situ technique, SAXS can provide new insights into the physicochemical steps involved in the biosynthesis of magnetosome nanoparticles as well as their assembly into well-ordered chains. The proposed fit model can easily be adapted to account for different particle shapes and arrangements produced by other strains of magnetotactic bacteria, thus rendering SAXS a highly versatile method.


Subject(s)
Magnetosomes/ultrastructure , Magnetospirillum/cytology , Magnetospirillum/metabolism , Nanostructures/chemistry , Bacterial Proteins , Evaluation Studies as Topic , Ferrosoferric Oxide , Membrane Proteins/metabolism , Microscopy, Electron , Scattering, Small Angle , X-Ray Diffraction
12.
J Antimicrob Chemother ; 74(5): 1376-1380, 2019 05 01.
Article in English | MEDLINE | ID: mdl-30668695

ABSTRACT

BACKGROUND: The AIDS Clinical Trials Group study A5353 demonstrated the efficacy and safety of dolutegravir and lamivudine for initial treatment of HIV-1 infection at week 24 in individuals with HIV-1 RNA 1000-500 000 copies/mL. Optimal ART for treatment-naive individuals must be durable. OBJECTIVES: The aim of this study was to estimate the efficacy and safety of dolutegravir plus lamivudine at week 48 and compare the efficacy in participants with baseline HIV-1 RNA ≤100 000 copies/mL versus >100 000 copies/mL. METHODS: Virological success was defined as HIV-1 RNA <50 copies/mL by FDA Snapshot criteria. Definition of virological failure included confirmed HIV-1 RNA >200 copies/mL at week 24 or later. The proportion of participants with virological success was estimated using two-sided exact Clopper-Pearson 95% CI. Comparison between screening HIV-1 RNA (≤100 000 versus >100 000 copies/mL) strata was carried out by Fisher's exact test. The study was registered with ClinicalTrials.gov, number NCT02582684. RESULTS: A total of 120 enrolled eligible participants were included in the analysis. At week 48, 102 of the 120 participants (85%; 95% CI 77%-91%) had virological success. Virological success was similar between screening HIV-1 RNA groups. Six (5%) participants had virological non-success and one additional participant experienced virological failure while on study but off study treatment. No new drug resistance mutations were observed. Six (5%) participants had study-related grade 3 or higher adverse events and none discontinued study treatment. CONCLUSIONS: These results add to the evidence that dolutegravir plus lamivudine is a safe and effective option for initial ART in individuals with HIV-1 RNA <500 000 copies/mL.


Subject(s)
Anti-HIV Agents/therapeutic use , HIV Infections/drug therapy , Heterocyclic Compounds, 3-Ring/therapeutic use , Lamivudine/therapeutic use , RNA, Viral/blood , Adult , Drug Resistance, Viral/genetics , Drug Therapy, Combination , Female , HIV Seropositivity/drug therapy , HIV-1/drug effects , Humans , Male , Mutation , Oxazines , Pilot Projects , Piperazines , Pyridones , Treatment Failure , Viral Load/drug effects , Young Adult
13.
AIDS Patient Care STDS ; 32(11): 450-458, 2018 11.
Article in English | MEDLINE | ID: mdl-30398955

ABSTRACT

Young racial/ethnic minority men who have sex with men (MSM) and transgender women with HIV often have poor health outcomes. They also utilize a wide array of social media. Accordingly, we developed and implemented weCare, a social media intervention utilizing Facebook, texting, and GPS-based mobile social and sexual networking applications to improve HIV-related care engagement and health outcomes. We compared viral load suppression and clinic appointment attendance among 91 participants during the 12-month period before and after weCare implementation. McNemar's chi-square test analyses were conducted comparing the pre- and postintervention difference using paired data. Since February 2016, intervention staff and 91 intervention participants (79.1% African American and 13.2% Latino, mean age = 25) exchanged 13,830 messages during 3,758 conversations (average: 41.3 conversations per participant) across a variety of topics, including appointment reminders, medication adherence, problem solving, and reducing barriers. There were significant reductions in missed HIV care appointments (68.0% vs. 53.3%, p = 0.04) and increases in viral load suppression (61.3% vs. 88.8%, p < 0.0001) 12 months postimplementation. Our results highlight the initial success of weCare in improving care engagement and viral suppression. Social media is an important tool, especially for young MSM and transgender women, to support individual- (e.g., viral suppression) and community- (e.g., reduced transmission efficiency) level health. It may also be a useful tool for improving engagement with biomedical HIV prevention tools (e.g., PrEP use).


Subject(s)
Anti-HIV Agents/therapeutic use , Continuity of Patient Care , HIV Infections/drug therapy , Homosexuality, Male/psychology , Social Media/statistics & numerical data , Transgender Persons , Adolescent , Adult , Black or African American , Ethnicity/psychology , Ethnicity/statistics & numerical data , Female , HIV Infections/ethnology , HIV Infections/psychology , Health Services Accessibility , Healthcare Disparities/ethnology , Hispanic or Latino , Homosexuality, Male/ethnology , Homosexuality, Male/statistics & numerical data , Humans , Male , Medication Adherence/ethnology , Minority Groups , Sexual Behavior , Sexual and Gender Minorities , Text Messaging , Treatment Outcome , Young Adult
14.
AIDS Educ Prev ; 30(3): 243-253, 2018 06.
Article in English | MEDLINE | ID: mdl-29969308

ABSTRACT

Throughout the world, we continue to face profound challenges to reducing the impact of the HIV epidemic. Community-engaged research has emerged as an approach to increase our understanding of HIV and reduce health disparities, increase health equity, and promote community and population health. Our partnership has conducted more than 25 community-engaged research studies in the U.S. and Guatemala, and members have identified nine themes to facilitate community-engaged research and expedite advances in HIV prevention, care, and treatment. These themes include the inclusion of multisectoral partners, trust building and maintenance, the alignment of partner priorities, a can-do attitude, capacity and desire to move beyond service and conduct research, flexibility, power sharing, empowerment, an assets orientation, the shared and timely use of findings, and a stepwise approach. To reduce HIV disparities, community-engaged research is as critical now as ever, and we desperately need to reinvigorate our commitment to and support of it.


Subject(s)
Community-Based Participatory Research/organization & administration , HIV Infections/prevention & control , HIV Infections/therapy , Homosexuality, Male , Adult , Guatemala , Humans , Male , Sexual Partners , United States
15.
PLoS Genet ; 12(6): e1006116, 2016 06.
Article in English | MEDLINE | ID: mdl-27362352

ABSTRACT

Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro-and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds.


Subject(s)
Cell Membrane/metabolism , Detergents/metabolism , Membrane Microdomains/metabolism , Membrane Proteins/metabolism , Bacillus subtilis/metabolism , Microscopy, Fluorescence/methods , Protein Transport/physiology
16.
JIMD Rep ; 27: 17-26, 2016.
Article in English | MEDLINE | ID: mdl-26404456

ABSTRACT

Cellular phenotyping of human dermal fibroblasts (HDFs) from patients with inherited diseases provides invaluable information for diagnosis, disease aetiology, prognosis and assessing of treatment options. Here we present a cell phenotyping protocol using image cytometry that combines measurements of crucial cellular and mitochondrial parameters: (1) cell number and viability, (2) thiol redox status (TRS), (3) mitochondrial membrane potential (MMP) and (4) mitochondrial superoxide levels (MSLs). With our protocol, cell viability, TRS and MMP can be measured in one small cell sample and MSL on a parallel one. We analysed HDFs from healthy individuals after treatment with various concentrations of hydrogen peroxide (H2O2) for different intervals, to mimic the physiological effects of oxidative stress. Our results show that cell number, viability, TRS and MMP decreased, while MSL increased both in a time- and concentration-dependent manner. To assess the use of our protocol for analysis of HDFs from patients with inherited diseases, we analysed HDFs from two patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (VLCADD), one with a severe clinical phenotype and one with a mild one. HDFs from both patients displayed increased MSL without H2O2 treatment. Treatment with H2O2 revealed significant differences in MMP and MSL between HDFs from the mild and the severe patient. Our results establish the capacity of our protocol for fast analysis of cellular and mitochondrial parameters by image cytometry in HDFs from patients with inherited metabolic diseases.

17.
Beilstein J Org Chem ; 10: 2332-2337, 2014.
Article in English | MEDLINE | ID: mdl-25298800

ABSTRACT

An efficient and divergent synthesis of polyol subunits utilizing a phosphate tether-mediated, one-pot, sequential RCM/CM/reduction process is reported. A modular, 3-component coupling strategy has been developed, in which, simple "order of addition" of a pair of olefinic-alcohol components to a pseudo-C 2-symmetric phosphoryl chloride, coupled with the RCM/CM/reduction protocol, yields five polyol fragments. Each of the product polyols bears a central 1,3-anti-diol subunit with differential olefinic geometries at the periphery.

18.
Clin Infect Dis ; 48(4): e47-9, 2009 Feb 15.
Article in English | MEDLINE | ID: mdl-19133803

ABSTRACT

We report the second case of severe postvaccinial encephalitis with acute disseminated encephalomyelitis since smallpox vaccination was reintroduced in 2002. Both affected patients responded dramatically with early intervention of intravenous immunoglobulin. Our patient, who also received concurrent vaccinia immunoglobulin and corticosteroids, demonstrated full recovery.


Subject(s)
Encephalomyelitis, Acute Disseminated/drug therapy , Immunoglobulins, Intravenous/therapeutic use , Immunologic Factors/therapeutic use , Smallpox Vaccine/adverse effects , Steroids/therapeutic use , Vaccinia/complications , Vaccinia/drug therapy , Adult , Encephalomyelitis, Acute Disseminated/chemically induced , Humans , Male , Treatment Outcome , Young Adult
19.
Mol Ecol ; 16(19): 4089-96, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17725572

ABSTRACT

Despite its often featureless appearance, the deep-ocean floor includes some of the most diverse habitats on Earth. However, the accurate assessment of global deep-sea diversity is impeded by a paucity of data on the geographical ranges of bottom-dwelling species, particularly at the genetic level. Here, we present molecular evidence for exceptionally wide distribution of benthic foraminifera, which constitute the major part of deep-sea meiofauna. Our analyses of nuclear ribosomal RNA genes revealed high genetic similarity between Arctic and Antarctic populations of three common deep-sea foraminiferal species (Epistominella exigua, Cibicides wuellerstorfi and Oridorsalis umbonatus), separated by distances of up to 17, 000 km. Our results contrast with the substantial level of cryptic diversity usually revealed by molecular studies, of shallow-water benthic and planktonic marine organisms. The very broad ranges of the deep-sea foraminifera that we examined support the hypothesis of global distribution of small eukaryotes and suggest that deep-sea biodiversity may be more modest at global scales than present estimates suggest.


Subject(s)
Biodiversity , Gene Flow , Antarctic Regions , Arctic Regions , Evolution, Molecular , Geography , Oceans and Seas , Phylogeny , RNA, Ribosomal/chemistry
20.
Infect Immun ; 74(3): 1612-20, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16495532

ABSTRACT

We investigated the immunogenicity of gonococcal transferrin binding protein B (TbpB) expressed with and without a eukaryotic secretion signal from a nonpropagating Venezuelan equine encephalitis virus replicon particle (VRP) delivery system. TbpB was successfully expressed in baby hamster kidney (BHK) cells, and the presence of the eukaryotic secretion signal not only apparently increased the protein's expression but also allowed for extracellular localization and glycosylation. Mice immunized with VRPs produced significant amounts of serum antibody although less than the amounts produced by mice immunized with recombinant protein. The response of mice immunized with VRPs encoding TbpB was consistently more Th1 biased than the response of mice immunized with recombinant protein alone. Boosting with recombinant protein following immunization with TbpB VRPs resulted in higher specific-antibody levels without altering the Th1/Th2 bias. Most of the immunization groups produced significant specific antibody binding to the intact surface of the homologous Neisseria gonorrhoeae strain. Immunization with TbpB VRPs without a eukaryotic secretion signal generated no measurable specific antibodies on the genital mucosal surface, but inclusion of a eukaryotic secretion signal or boosting with recombinant protein resulted in specific immunoglobulin G (IgG) and IgA in mucosal secretions after TbpB VRP immunization. The TbpB VRP system has potential for an N. gonorrhoeae vaccine.


Subject(s)
Antibodies, Bacterial/biosynthesis , Bacterial Vaccines/administration & dosage , Gonorrhea/immunology , Neisseria gonorrhoeae/chemistry , Recombinant Proteins/immunology , Replicon/physiology , Transferrin-Binding Protein B/administration & dosage , Animals , Antigens, Bacterial/administration & dosage , Antigens, Bacterial/genetics , Antigens, Bacterial/immunology , Bacterial Vaccines/genetics , Bacterial Vaccines/immunology , Encephalitis Virus, Venezuelan Equine/genetics , Female , Immunoglobulin A/biosynthesis , Mice , Mice, Inbred BALB C , Neisseria gonorrhoeae/genetics , Recombinant Proteins/administration & dosage , Recombinant Proteins/genetics , Replicon/genetics , Transferrin-Binding Protein B/genetics , Transferrin-Binding Protein B/immunology , Vaccination , Vagina/immunology
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