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1.
Environ Monit Assess ; 196(6): 531, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38724710

RESUMEN

The Samarco/Vale/BHP mine tailing dam breach that took place in Minas Gerais, southeastern Brazil, in 2015, deposited high concentrations of metals and metalloids in the Rio Doce basin, severely impacting freshwater and riverine forest ecosystems. To assess developmental instability of caddisflies in response to the environmental impacts of the dam breach, we investigated the fluctuating asymmetry (FA) in the species Smicridea (Rhyacophylax) coronata (Trichoptera: Hydropsychidae). FA was assessed at individual and populational scales using geometric morphometric methods in the cephalic capsule and mandibles of larvae and also on the forewings of adults, both collected under the impacted condition, and under the least disturbed condition. The levels of FA increased in response to stressors on the forewings at the populational scale, and on the mandibles, at individual scale. These morphological variations in the larval and adult stages may lead to detrimental effects and result in high mortality rates as well as lower adult fitness. Trichoptera forewings are revealed as suitable traits for assessing FA, holding potential for applications in biomonitoring programs. Directional asymmetry levels were higher than FA levels for all traits, and this correlation could be explained by a transition from fluctuating to directional asymmetry in the presence of heightened disturbance. Our results validate the relationship between the impacts from the dam breach and increased developmental instability in this species with likely cascade effects on the insect community.


Asunto(s)
Monitoreo del Ambiente , Larva , Minería , Animales , Larva/crecimiento & desarrollo , Insectos , Brasil , Contaminantes Químicos del Agua
2.
PLoS Pathog ; 17(8): e1009772, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34352039

RESUMEN

Understanding SARS-CoV-2 evolution and host immunity is critical to control COVID-19 pandemics. At the core is an arms-race between SARS-CoV-2 antibody and angiotensin-converting enzyme 2 (ACE2) recognition, a function of the viral protein spike. Mutations in spike impacting antibody and/or ACE2 binding are appearing worldwide, imposing the need to monitor SARS-CoV2 evolution and dynamics in the population. Determining signatures in SARS-CoV-2 that render the virus resistant to neutralizing antibodies is critical. We engineered 25 spike-pseudotyped lentiviruses containing individual and combined mutations in the spike protein, including all defining mutations in the variants of concern, to identify the effect of single and synergic amino acid substitutions in promoting immune escape. We confirmed that E484K evades antibody neutralization elicited by infection or vaccination, a capacity augmented when complemented by K417N and N501Y mutations. In silico analysis provided an explanation for E484K immune evasion. E484 frequently engages in interactions with antibodies but not with ACE2. Importantly, we identified a novel amino acid of concern, S494, which shares a similar pattern. Using the already circulating mutation S494P, we found that it reduces antibody neutralization of convalescent and post-immunization sera, particularly when combined with E484K and with mutations able to increase binding to ACE2, such as N501Y. Our analysis of synergic mutations provides a signature for hotspots for immune evasion and for targets of therapies, vaccines and diagnostics.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , COVID-19/virología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Sustitución de Aminoácidos/genética , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/inmunología , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/inmunología , Línea Celular , Humanos , Evasión Inmune , Mutación/genética , Unión Proteica , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo
3.
Gastroenterology ; 160(3): 941-945.e8, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33197449

RESUMEN

The increasing incidence of primary and recurring Clostridioides difficile infections (CDI), which evade current treatment strategies, reflects the changing biology of C difficile. Here, we describe a putative plasmid-mediated mechanism potentially driving decreased sensitivity of C difficile to vancomycin treatment. We identified a broad host range transferable plasmid in a C difficile strain associated with lack of adequate response to vancomycin treatment. The transfer of this plasmid to a vancomycin-susceptible C difficile isolate decreased its susceptibility to vancomycin in vitro and resulted in more severe disease in a humanized mouse model. Our findings suggest plasmid acquisition in the gastrointestinal tract to be a possible mechanism underlying vancomycin treatment failure in patients with CDI, but further work is needed to characterize the mechanism by which plasmid genes determine vancomycin susceptibility in C difficile.


Asunto(s)
Antibacterianos/farmacología , Clostridioides difficile/genética , Infecciones por Clostridium/tratamiento farmacológico , Plásmidos/genética , Vancomicina/farmacología , Animales , Antibacterianos/uso terapéutico , Clostridioides difficile/efectos de los fármacos , Clostridioides difficile/aislamiento & purificación , Infecciones por Clostridium/microbiología , Modelos Animales de Enfermedad , Farmacorresistencia Bacteriana/genética , Vida Libre de Gérmenes , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Plásmidos/aislamiento & purificación , Vancomicina/uso terapéutico , Secuenciación Completa del Genoma
4.
Appl Microbiol Biotechnol ; 105(4): 1379-1394, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33521847

RESUMEN

The incorporation of nanomaterials (NMs), including metal(loid) oxide (MOx) nanoparticles (NPs), in the most diversified consumer products, has grown enormously in recent decades. Consequently, the contact between humans and these materials increased, as well as their presence in the environment. This fact has raised concerns and uncertainties about the possible risks of NMs to human health and the adverse effects on the environment. These concerns underline the need and importance of assessing its nanosecurity. The present review focuses on the main mechanisms underlying the MOx NPs toxicity, illustrated with different biological models: release of toxic ions, cellular uptake of NPs, oxidative stress, shading effect on photosynthetic microorganisms, physical restrain and damage of cell wall. Additionally, the biological models used to evaluate the potential hazardous of nanomaterials are briefly presented, with particular emphasis on the yeast Saccharomyces cerevisiae, as an alternative model in nanotoxicology. An overview containing recent scientific advances on cellular responses (toxic symptoms exhibited by yeasts) resulting from the interaction with MOx NPs (inhibition of cell proliferation, cell wall damage, alteration of function and morphology of organelles, presence of oxidative stress bio-indicators, gene expression changes, genotoxicity and cell dead) is critically presented. The elucidation of the toxic modes of action of MOx NPs in yeast cells can be very useful in providing additional clues about the impact of NPs on the physiology and metabolism of the eukaryotic cell. Current and future trends of MOx NPs toxicity, regarding their possible impacts on the environment and human health, are discussed. KEY POINTS: • The potential hazardous effects of MOx NPs are critically reviewed. • An overview of the main mechanisms associated with MOx NPs toxicity is presented. • Scientific advances about yeast cell responses to MOx NPs are updated and discussed.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Humanos , Iones , Nanopartículas del Metal/toxicidad , Metales , Nanopartículas/toxicidad , Estrés Oxidativo , Óxidos
5.
BMC Pregnancy Childbirth ; 21(1): 632, 2021 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-34535094

RESUMEN

BACKGROUND: Immunological protection via breastfeeding is well known. The immunological profile of human milk changes during lactation. No clinical trials have been conducted in lactating women with the newest mRNA vaccines against SARS- CoV-2. A Few studies have shown the presence of antibodies in breastmilk after vaccination. The aim of this work is to study possible antibodies transfer via breastmilk and also the immunological characteristics of lactating women compared to non-lactating women, after using the BNT162b2 Pfizer vaccine. METHODS: This is a prospective cohort study with a convenience homogenous sample of 24 healthcare workers (14 lactating and 10 non-lactating women) enrolled at the time of COVID-19 vaccination. Clinical data was registered in a questionnaire. Titers of SARS-CoV-2 spike IgG, IgA and IgM were quantified in post vaccination blood and human milk. Antibody quantification was performed by an in-house ELISA to SARS-CoV-2 trimeric spike protein. RESULTS: All women showed immunity after vaccination with positive antibodies for IgM, IgA and IgG antibodies. The dominant serum antibody response was IgG. Modest levels of antibodies in breastmilk of lactating mothers were observed in this study, especially IgG in 42.9%. There was a moderate association between higher titers of IgG and a longer duration of breastfeeding (R= 0.55, p=0.041). CONCLUSIONS: Evidence of antibody transfer in human milk after COVID-19 vaccination is scarce. The presence of antibodies in human milk is reported, but immunization through breastfeeding is still to be established.


Asunto(s)
Anticuerpos Antivirales/metabolismo , Lactancia Materna , Vacunas contra la COVID-19/inmunología , COVID-19/prevención & control , Lactancia/inmunología , Leche Humana/inmunología , SARS-CoV-2/inmunología , Adulto , Vacuna BNT162 , Biomarcadores/metabolismo , COVID-19/inmunología , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunización Pasiva , Estudios Prospectivos
6.
Int J Mol Sci ; 22(10)2021 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-34069929

RESUMEN

The success of antiretroviral treatment (ART) is threatened by the emergence of drug resistance mutations (DRM). Since Brazil presents the largest number of people living with HIV (PLWH) in South America we aimed at understanding the dynamics of DRM in this country. We analyzed a total of 20,226 HIV-1 sequences collected from PLWH undergoing ART between 2008-2017. Results show a mild decline of DRM over the years but an increase of the K65R reverse transcriptase mutation from 2.23% to 12.11%. This increase gradually occurred following alterations in the ART regimens replacing zidovudine (AZT) with tenofovir (TDF). PLWH harboring the K65R had significantly higher viral loads than those without this mutation (p < 0.001). Among the two most prevalent HIV-1 subtypes (B and C) there was a significant (p < 0.001) association of K65R with subtype C (11.26%) when compared with subtype B (9.27%). Nonetheless, evidence for K65R transmission in Brazil was found both for C and B subtypes. Additionally, artificial neural network-based immunoinformatic predictions suggest that K65R could enhance viral recognition by HLA-B27 that has relatively low prevalence in the Brazilian population. Overall, the results suggest that tenofovir-based regimens need to be carefully monitored particularly in settings with subtype C and specific HLA profiles.


Asunto(s)
Farmacorresistencia Viral/genética , Infecciones por VIH/genética , Adenina/uso terapéutico , Adulto , Anciano , Fármacos Anti-VIH/farmacología , Brasil/epidemiología , Farmacorresistencia Viral/fisiología , Femenino , Infecciones por VIH/tratamiento farmacológico , Transcriptasa Inversa del VIH/genética , VIH-1/efectos de los fármacos , VIH-1/genética , VIH-1/patogenicidad , Humanos , Masculino , Persona de Mediana Edad , Mutación/efectos de los fármacos , Inhibidores de la Transcriptasa Inversa/farmacología , Tenofovir/uso terapéutico , Insuficiencia del Tratamiento , Carga Viral/efectos de los fármacos , Zidovudina/uso terapéutico
7.
Molecules ; 26(21)2021 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-34771129

RESUMEN

We report herein a set of 3'-azido-3'-deoxythymidine (AZT) derivatives based on triazoles and triazolium salts for HIV-1 infection. The compounds were synthesized via click chemistry with Cu(I) and Ru(II) catalysts. Triazolium salts were synthesized by reaction with methyl iodide or methyl triflate in good yields. The antiviral activity of the compounds was tested using two methodologies: In method one the activity was measured on infected cells; in method two a pre-exposure prophylaxis experimental model was employed. For method one the activity of the compounds was moderate, and in general the triazolium salts showed a decreased activity in relation to their triazole precursors. With method two the antiviral activity was higher. All compounds were able to decrease the infection, with two compounds able to clear almost all the infection, while a lower antiviral activity was noted for the triazolium salts. These results suggest that these drugs could play an important role in the development of pre-exposure prophylaxis therapies.


Asunto(s)
Fármacos Anti-VIH/farmacología , Desarrollo de Medicamentos , VIH-1/efectos de los fármacos , Triazoles/farmacología , Zidovudina/farmacología , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Sales (Química)/síntesis química , Sales (Química)/química , Sales (Química)/farmacología , Triazoles/síntesis química , Triazoles/química , Zidovudina/síntesis química , Zidovudina/química
8.
J Clin Rheumatol ; 26(7): 289-294, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31397760

RESUMEN

INTRODUCTION: Hypovitaminosis D has been frequently described in systemic sclerosis (SSc). Cytokines are important mediators of tissue damage and clinical dysfunction in SSc and may be influenced by vitamin D levels. OBJECTIVE: To evaluate the serum levels of vitamin D and its correlation with the clinical features and cytokine profiles in SSc patients. METHODS: Case-control study, including 50 SSc patients and 35 healthy non matched controls. Serum levels of 25(OH) vitamin D were measured by chemiluminescence assay, and serum concentrations of interleukin 2 (IL-2), IL-4, IL-6, IL-10, tumor necrosis factor, and interferon γ were determined by flow cytometry. RESULTS: Fourteen patients (28%) had diffuse cutaneous SSc, 94% were female, 80% European derived, with a mean age of 57.2 ± 12.8 years. The serum vitamin D levels in SSc patients were 23.9 ± 8.5 ng/mL and 30.2 ± 6.2 ng/mL in the control group (standardized mean difference -6.19; 95% confidence interval, -9.9 to -2.3; p = 0.002), despite the more frequent supplementation of vitamin D in SSc patients (p = 0.014). No significant associations were found among vitamin D concentrations and cytokine levels. Serum levels of IL-6 were significantly elevated in SSc patients (p = 0.024) and were positively correlated with the modified Rodnan skin score (rs = 0.291, p =0.041). CONCLUSIONS: Despite lower vitamin D levels in SSc patients, there was no clear association with any cytokine. Serum levels of IL-6 were significantly elevated and positively correlated with the extent of skin involvement in SSc patients.


Asunto(s)
Esclerodermia Sistémica , Deficiencia de Vitamina D , Adulto , Anciano , Estudios de Casos y Controles , Citocinas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerodermia Sistémica/diagnóstico , Vitamina D , Deficiencia de Vitamina D/complicaciones , Deficiencia de Vitamina D/diagnóstico
9.
Chem Res Toxicol ; 32(2): 245-254, 2019 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-30656935

RESUMEN

The expansion of the industrial use of nickel oxide (NiO) nanoparticles (NPs) raises concerns about their potential adverse effects. Our work aimed to investigate the mechanisms of toxicity induced by NiO NPs, using the yeast Saccharomyces cerevisiae as a cell model. Yeast cells exposed to NiO NPs exhibited typical hallmarks of regulated cell death (RCD) by apoptosis [loss of cell proliferation capacity (cell viability), exposure of phosphatidylserine at the outer cytoplasmic membrane leaflet, nuclear chromatin condensation, and DNA damage] in a process that required de novo protein synthesis. The execution of yeast cell death induced by NiO NPs is Yca1p metacaspase-dependent. NiO NPs also induced a decrease in the mitochondrial membrane potential and an increase in the frequency of respiratory-deficient mutants, which supports the involvement of mitochondria in the cell death process. Cells deficient in the apoptosis-inducing factor ( aif1Δ) displayed higher tolerance to NiO NPs, which reinforces the involvement of mitochondria in RCD by apoptosis. In summary, this study shows that NiO NPs induce caspase- and mitochondria-dependent apoptosis in yeast. Our results warn about the possible harmful effects associated with the use of NiO NPs.


Asunto(s)
Apoptosis/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Nanopartículas/toxicidad , Níquel/química , Saccharomyces cerevisiae/metabolismo , Caspasas/metabolismo , Daño del ADN/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , Nanopartículas/química , Saccharomyces cerevisiae/efectos de los fármacos , Proteínas de Saccharomyces cerevisiae/metabolismo
10.
Appl Microbiol Biotechnol ; 103(15): 6257-6269, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31152204

RESUMEN

In this work, the physicochemical characterization of five (Al2O3, In2O3, Mn3O4, SiO2 and SnO2) nanoparticles (NPs) was carried out. In addition, the evaluation of the possible toxic impacts of these NPs and the respective modes of action were performed using the yeast Saccharomyces cerevisiae. In general, in aqueous suspension, metal(loid) oxide (MOx) NPs displayed an overall negative charge and agglomerated; these NPs were practically insoluble (dissolution < 8%) and did not generate detectable amounts of reactive oxygen species (ROS) under abiotic conditions. Except In2O3 NPs, which did not induce an obvious toxic effect on yeast cells (up to 100 mg/L), the other NPs induced a loss of cell viability in a dose-dependent manner. The comparative analysis of the loss of cell viability induced by the NPs with the ions released by NPs (NPs supernatant) suggested that SiO2 toxicity was mainly caused by the NPs themselves, Al2O3 and SnO2 toxic effects could be attributed to both the NPs and the respective released ions and Mn3O4 harmfulness could be mainly due to the released ions. Al2O3, Mn3O4, SiO2 and SnO2 NPs induced the loss of metabolic activity and the generation of intracellular ROS without permeabilization of plasma membrane. The co-incubation of yeast cells with MOx NPs and a free radical scavenger (ascorbic acid) quenched intracellular ROS and significantly restored cell viability and metabolic activity. These results evidenced that the intracellular generation of ROS constituted the main cause of the cytotoxicity exhibited by yeasts treated with the MOx NPs. This study highlights the importance of a ROS-mediated mechanism in the toxicity induced by MOx NPs.


Asunto(s)
Nanopartículas del Metal/toxicidad , Metaloides/toxicidad , Viabilidad Microbiana/efectos de los fármacos , Óxidos/toxicidad , Especies Reactivas de Oxígeno/metabolismo , Saccharomyces cerevisiae/efectos de los fármacos , Fenómenos Químicos , Relación Dosis-Respuesta a Droga , Metabolismo/efectos de los fármacos , Nanopartículas del Metal/química , Metaloides/química , Óxidos/química , Solubilidad
11.
Bioinformatics ; 33(15): 2416-2418, 2017 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-28379466

RESUMEN

SUMMARY: Reconstructing and analyzing a large number of genome-scale metabolic models is a fundamental part of the integrated study of microbial communities; however, two of the most widely used frameworks for building and analyzing models use different metabolic network representations. Here we describe Mackinac, a Python package that combines ModelSEED's ability to automatically reconstruct metabolic models with COBRApy's advanced analysis capabilities to bridge the differences between the two frameworks and facilitate the study of the metabolic potential of microorganisms. AVAILABILITY AND IMPLEMENTATION: This package works with Python 2.7, 3.4, and 3.5 on MacOS, Linux and Windows. The source code is available from https://github.com/mmundy42/mackinac . CONTACT: mundy.michael@mayo.edu or soares.maria@mayo.edu.


Asunto(s)
Bacterias/metabolismo , Biología Computacional/métodos , Redes y Vías Metabólicas , Modelos Biológicos , Programas Informáticos , Genoma
12.
Chem Res Toxicol ; 31(8): 658-665, 2018 08 20.
Artículo en Inglés | MEDLINE | ID: mdl-30043610

RESUMEN

The present work aimed to elucidate whether the toxic effects of nickel oxide (NiO) nanoparticles (NPs) on the yeast Saccharomyces cerevisiae were associated with oxidative stress (OS) and what mechanisms may have contributed to this OS. Cells exposed to NiO NPs accumulated superoxide anions and hydrogen peroxide, which were intracellularly generated. Yeast cells coexposed to NiO NPs and antioxidants (l-ascorbic acid and N- tert-butyl-α-phenylnitrone) showed quenching of reactive oxygen species (ROS) and increased resistance to NiO NPs, indicating that the loss of cell viability was associated with ROS accumulation. Mutants lacking mitochondrial DNA (ρ0) displayed reduced levels of ROS and increased resistance to NiO NPs, which suggested the involvement of the mitochondrial respiratory chain in ROS production. Yeast cells exposed to NiO NPs presented decreased levels of reduced glutathione (GSH). Mutants deficient in GSH1 ( gsh1Δ) or GSH2 ( gsh2Δ) genes displayed increased levels of ROS and increased sensitivity to NiO NPs, which underline the central role of GSH against NiO NPs-induced OS. This work suggests that the increased levels of intracellular ROS (probably due to the perturbation of the electron transfer chain in mitochondria) combined with the depletion of GSH pool constitute important mechanisms of NiO NPs-induced loss of cell viability in the yeast S. cerevisiae.


Asunto(s)
Nanopartículas del Metal/toxicidad , Níquel/toxicidad , Estrés Oxidativo , Saccharomyces cerevisiae/efectos de los fármacos , Antioxidantes/farmacología , ADN Mitocondrial/metabolismo , Transporte de Electrón , Glutatión/metabolismo , Mutación , Especies Reactivas de Oxígeno/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo
13.
J Immunol ; 197(10): 4042-4052, 2016 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-27798165

RESUMEN

The ability of HIV-1 to replicate and to establish long-term reservoirs is strongly influenced by T cell activation. Through the use of membrane-tethered, genetically encoded calcium (Ca2+) indicators, we were able to detect for the first time, to our knowledge, the formation of Ca2+ territories and determine their role in coordinating the functional signaling nanostructure of the synaptic membrane. Consequently, we report a previously unknown immune subversion mechanism involving HIV-1 exploitation, through its Nef accessory protein, of the interconnectivity among three evolutionarily conserved cellular processes: vesicle traffic, signaling compartmentalization, and the second messenger Ca2+ We found that HIV-1 Nef specifically associates with the traffic regulators MAL and Rab11b compelling the vesicular accumulation of Lck. Through its association with MAL and Rab11b, Nef co-opts Lck switchlike function driving the formation Ca2+ membrane territories, which, in turn, control the fusion of LAT-transporting Rab27 and Rab37 vesicles and the formation of LAT nanoclusters at the immunological synapse. Consequently, HIV-1 Nef disengages TCR triggering from the generation of p-LAT and p-SLP nanoclusters driving TCR signal amplification and diversification. Altogether our results indicate that HIV-1 exploits the interconnectivity among vesicle traffic, Ca2+ membrane territories, and signaling nanoclusters to modulate T cell signaling and function.


Asunto(s)
Calcio/metabolismo , VIH-1/fisiología , Sinapsis Inmunológicas/metabolismo , Transducción de Señal , Linfocitos T/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/metabolismo , Células HEK293 , VIH-1/inmunología , Humanos , Sinapsis Inmunológicas/ultraestructura , Células Jurkat , Activación de Linfocitos , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Glicoproteínas de Membrana/metabolismo , Fosforilación , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Interleucina-1/metabolismo , Linfocitos T/metabolismo , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/química , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología , Proteínas de Unión al GTP rab/metabolismo , Proteínas rab27 de Unión a GTP
14.
Appl Microbiol Biotechnol ; 102(6): 2827-2838, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29423633

RESUMEN

The increasing use of nanoparticles (NPs) has spurred concerns about their toxic effects. This work aimed to assess the potential hazards of nickel oxide (NiO) NPs using the yeast Saccharomyces cerevisiae as a cell model. Yeast cells exposed for 6 h to 100 mg/L NiO NPs presented reduced metabolic activity (esterase activity and FUN-1 dye processing) and enhanced accumulation of reactive oxygen species. NiO NPs induced the loss of cell viability in a dose-dependent manner. Study of the dissolution of NiO NPs in aqueous media, together with the toxicological data, suggests that the nickel released by the NPs cannot explain all the toxic effects observed in S. cerevisiae caused by the NPs. Transmission electron microscopy observations revealed that NiO NPs were adsorbed onto cell surface but did not enter into yeast cells. Isogenic mutants (cwp1∆ and cwp2∆) with increased cell wall porosity did not display enhanced susceptibility to NiO NPs compared to the wild type strain. Our results suggest that NiO NPs exert their toxic effect by an indirect mechanism. This work contributes to knowledge of the potential hazards of NiO NPs and to the elucidation of their mechanisms of toxic action.


Asunto(s)
Viabilidad Microbiana/efectos de los fármacos , Nanopartículas/toxicidad , Níquel/toxicidad , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/fisiología , Adsorción , Microscopía Electrónica de Transmisión , Nanopartículas/ultraestructura , Especies Reactivas de Oxígeno/análisis , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/ultraestructura , Propiedades de Superficie
16.
Yeast ; 34(9): 383-395, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28581036

RESUMEN

During exposure of yeast cells to low levels of hydrogen peroxide (H2 O2 ), the expression of several genes is regulated for cells to adapt to the surrounding oxidative environment. Such adaptation involves modification of plasma membrane lipid composition, reorganization of ergosterol-rich microdomains and altered gene expression of proteins involved in lipid and vesicle traffic, to decrease permeability to exogenous H2 O2 . Opi1p is a transcriptional repressor that is inactive when present at the nuclear membrane/endoplasmic reticulum, but represseses transcription of inositol upstream activating sequence (UASINO )-containing genes, many of which are involved in the synthesis of phospholipids and fatty acids, when it is translocated to the nucleus. We investigated whether H2 O2 in concentrations inducing adaptation regulates Opi1p function. We found that, in the presence of H2 O2 , GFP-Opi1p fusion protein translocates to the nucleus and, concomitantly, the expression of UASINO -containing genes is affected. We also investigated whether cysteine residues of Opi1p were implicated in the H2 O2 -mediated translocation of this protein to the nucleus and identified cysteine residue 159 as essential for this process. Our work shows that Opi1p is redox-regulated and establishes a new mechanism of gene regulation involving Opi1p, which is important for adaptation to H2 O2 in yeast cells. Copyright © 2017 John Wiley & Sons, Ltd.


Asunto(s)
Núcleo Celular/metabolismo , Retículo Endoplásmico/metabolismo , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Proteínas Represoras/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Adaptación Biológica , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/efectos de los fármacos , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Ácidos Grasos/biosíntesis , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Inositol/análisis , Inositol/química , Microdominios de Membrana/metabolismo , Proteínas de Transporte de Monosacáridos/efectos de los fármacos , Proteínas de Transporte de Monosacáridos/genética , Mio-Inositol-1-Fosfato Sintasa/efectos de los fármacos , Mio-Inositol-1-Fosfato Sintasa/genética , Oxidación-Reducción , Estrés Oxidativo , Permeabilidad , Fosfolípidos/biosíntesis , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/efectos de los fármacos
17.
Immunol Rev ; 256(1): 118-32, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24117817

RESUMEN

Immunological synapses are specialized cell-cell contacts formed between T lymphocytes and antigen-presenting cells. They are induced upon antigen recognition and are crucial for T-cell activation and effector functions. The generation and function of immunological synapses depend on an active T-cell polarization process, which results from a finely orchestrated crosstalk between the antigen receptor signal transduction machinery, the actin and microtubule cytoskeletons, and controlled vesicle traffic. Although we understand how some of these particular events are regulated, we still lack knowledge on how these multiple cellular elements are harmonized to ensure appropriate T-cell responses. We discuss here our view on how T-cell receptor signal transduction initially commands cytoskeletal and vesicle traffic polarization, which in turn sets the immunological synapse molecular design that regulates T-cell activation. We also discuss how the human immunodeficiency virus (HIV-1) hijacks some of these processes impairing immunological synapse generation and function.


Asunto(s)
Citoesqueleto/fisiología , Sinapsis Inmunológicas/fisiología , Vesículas Transportadoras/metabolismo , Animales , Transporte Biológico , VIH/fisiología , Humanos , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/virología
18.
BMC Bioinformatics ; 17(1): 343, 2016 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-27590448

RESUMEN

BACKGROUND: The explosive growth of microbiome research has yielded great quantities of data. These data provide us with many answers, but raise just as many questions. 16S rDNA-the backbone of microbiome analyses-allows us to assess α-diversity, ß-diversity, and microbe-microbe associations, which characterize the overall properties of an ecosystem. However, we are still unable to use 16S rDNA data to directly assess the microbe-microbe and microbe-environment interactions that determine the broader ecology of that system. Thus, properties such as competition, cooperation, and nutrient conditions remain insufficiently analyzed. Here, we apply predictive community metabolic models of microbes identified with 16S rDNA data to probe the ecology of microbial communities. RESULTS: We developed a methodology for the large-scale assessment of microbial metabolic interactions (MMinte) from 16S rDNA data. MMinte assesses the relative growth rates of interacting pairs of organisms within a community metabolic network and whether that interaction has a positive or negative effect. Moreover, MMinte's simulations take into account the nutritional environment, which plays a strong role in determining the metabolism of individual microbes. We present two case studies that demonstrate the utility of this software. In the first, we show how diet influences the nature of the microbe-microbe interactions. In the second, we use MMinte's modular feature set to better understand how the growth of Desulfovibrio piger is affected by, and affects the growth of, other members in a simplified gut community under metabolic conditions suggested to be determinant for their dynamics. CONCLUSION: By applying metabolic models to commonly available sequence data, MMinte grants the user insight into the metabolic relationships between microbes, highlighting important features that may relate to ecological stability, susceptibility, and cross-feeding. These relationships are at the foundation of a wide range of ecological questions that impact our ability to understand problems such as microbially-derived toxicity in colon cancer.


Asunto(s)
Metabolismo , Microbiota , Programas Informáticos , Bacterias/metabolismo , Redes y Vías Metabólicas , Modelos Biológicos , Especificidad de la Especie
19.
Appl Environ Microbiol ; 82(24): 7063-7073, 2016 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-27694231

RESUMEN

Lactobacillus crispatus and Lactobacillus iners are common inhabitants of the healthy human vagina. These two species are closely related and are thought to perform similar ecological functions in the vaginal environment. Temporal data on the vaginal microbiome have shown that nontransient instances of cooccurrence are uncommon, while transitions from an L. iners-dominated community to one dominated by L. crispatus, and vice versa, occur often. This suggests that there is substantial overlap in the fundamental niches of these species. Given this apparent niche overlap, it is unclear how they have been maintained as common inhabitants of the human vagina. In this study, we characterized and compared the genomes of L. iners and L. crispatus to gain insight into possible mechanisms driving the maintenance of this species diversity. Our results highlight differences in the genomes of these two species that may facilitate the partitioning of their shared niche space. Many of the identified differences may impact the protective benefits provided to the host by these two species. IMPORTANCE: The microbial communities that inhabit the human vagina play a critical role in the maintenance of vaginal health through the production of lactic acid and lowering the environmental pH. This precludes the growth of nonindigenous organisms and protects against infectious disease. The two most common types of vaginal communities are dominated by either Lactobacillus iners or Lactobacillus crispatus, while some communities alternate between the two over time. We combined ecological theory with state-of-the-art genome analyses to characterize how these two species might partition their shared niche space in the vagina. We show that the genomes of L. iners and L. crispatus differ in many respects, several of which may drive differences in their competitive abilities in the vagina. Our results provide insight into factors that drive the complicated temporal dynamics of the vaginal microbiome and demonstrate how closely related microbial species partition shared fundamental niche space.


Asunto(s)
Biodiversidad , Lactobacillus crispatus/genética , Lactobacillus/genética , Vagina/microbiología , Evolución Molecular , Femenino , Genoma Bacteriano , Genómica , Humanos , Lactobacillus/clasificación , Lactobacillus/aislamiento & purificación , Lactobacillus crispatus/clasificación , Lactobacillus crispatus/aislamiento & purificación , Filogenia
20.
Parasitology ; 143(8): 957-70, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27041483

RESUMEN

Invasive stages of apicomplexan parasites require a host cell to survive, proliferate and advance to the next life cycle stage. Once invasion is achieved, apicomplexans interact closely with the host cell cytoskeleton, but in many cases the different species have evolved distinct mechanisms and pathways to modulate the structural organization of cytoskeletal filaments. The host cell cytoskeleton is a complex network, largely, but not exclusively, composed of microtubules, actin microfilaments and intermediate filaments, all of which are modulated by associated proteins, and it is involved in diverse functions including maintenance of cell morphology and mechanical support, migration, signal transduction, nutrient uptake, membrane and organelle trafficking and cell division. The ability of apicomplexans to modulate the cytoskeleton to their own advantage is clearly beneficial. We here review different aspects of the interactions of apicomplexans with the three main cytoskeletal filament types, provide information on the currently known parasite effector proteins and respective host cell targets involved, and how these interactions modulate the host cell physiology. Some of these findings could provide novel targets that could be exploited for the development of preventive and/or therapeutic strategies.


Asunto(s)
Apicomplexa/fisiología , Citoesqueleto/metabolismo , Interacciones Huésped-Parásitos , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestructura , Animales , Citoesqueleto/ultraestructura , Microtúbulos/metabolismo , Microtúbulos/ultraestructura , Orgánulos/metabolismo , Orgánulos/ultraestructura , Transducción de Señal
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