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

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Nucleic Acids Res ; 52(2): 708-723, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38000366

RESUMEN

Replication of Vibrio cholerae chromosome 2 (Chr2) initiates when the Chr1 locus, crtS (Chr2 replication triggering site) duplicates. The site binds the Chr2 initiator, RctB, and the binding increases when crtS is complexed with the transcription factor, Lrp. How Lrp increases the RctB binding and how RctB is subsequently activated for initiation by the crtS-Lrp complex remain unclear. Here we show that Lrp bends crtS DNA and possibly contacts RctB, acts that commonly promote DNA-protein interactions. To understand how the crtS-Lrp complex enhances replication, we isolated Tn-insertion and point mutants of RctB, selecting for retention of initiator activity without crtS. Nearly all mutants (42/44) still responded to crtS for enhancing replication, exclusively in an Lrp-dependent manner. The results suggest that the Lrp-crtS controls either an essential function or more than one function of RctB. Indeed, crtS modulates two kinds of RctB binding to the origin of Chr2, ori2, both of which we find to be Lrp-dependent. Some point mutants of RctB that are optimally modulated for ori2 binding without crtS still remained responsive to crtS and Lrp for replication enhancement. We infer that crtS-Lrp functions as a unit, which has an overarching role, beyond controlling initiator binding to ori2.


Asunto(s)
Proteínas Bacterianas , Replicación del ADN , Proteína Reguladora de Respuesta a la Leucina , Vibrio cholerae , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ADN/metabolismo , Regulación Bacteriana de la Expresión Génica , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Vibrio cholerae/genética , Vibrio cholerae/metabolismo , Proteína Reguladora de Respuesta a la Leucina/metabolismo
2.
Nucleic Acids Res ; 48(19): 11016-11029, 2020 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-33035310

RESUMEN

Studies of bacterial chromosomes and plasmids indicate that their replication initiator proteins bind to origins of replication at many double-stranded sites and also at AT-rich regions where single-stranded DNA is exposed during origin opening. Single-strand binding apparently promotes origin opening by stabilizing an open structure, but how the initiator participates in this process and the contributions of the several binding sites remain unclear. Here, we show that the initiator protein of Vibrio cholerae specific to chromosome 2 (Chr2) also has single-strand binding activity in the AT-rich region of its origin. Binding is strand specific, depends on repeats of the sequence 5'ATCA and is greatly stabilized in vitro by specific double-stranded sites of the origin. The stability derives from the formation of ternary complexes of the initiator with the single- and double-stranded sites. An IHF site lies between these two kinds of sites in the Chr2 origin and an IHF-induced looping out of the intervening DNA mediates their interaction. Simultaneous binding to two kinds of sites in the origin appears to be a common mechanism by which bacterial replication initiators stabilize an open origin.


Asunto(s)
Proteínas Bacterianas/metabolismo , Cromosomas Bacterianos/metabolismo , ADN Helicasas/metabolismo , Replicación del ADN , ADN Bacteriano/metabolismo , Proteínas de Unión al ADN/metabolismo , Transactivadores/metabolismo , Vibrio cholerae/genética , Sitios de Unión , Regulación Bacteriana de la Expresión Génica , Unión Proteica , Origen de Réplica
3.
Nucleic Acids Res ; 48(1): 200-211, 2020 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-31665475

RESUMEN

Escherichia coli replication initiator protein DnaA binds ATP with high affinity but the amount of ATP required to initiate replication greatly exceeds the amount required for binding. Previously, we showed that ATP-DnaA, not ADP-DnaA, undergoes a conformational change at the higher nucleotide concentration, which allows DnaA oligomerization at the replication origin but the association state remains unclear. Here, we used Small Angle X-ray Scattering (SAXS) to investigate oligomerization of DnaA in solution. Whereas ADP-DnaA was predominantly monomeric, AMP-PNP-DnaA (a non-hydrolysable ATP-analog bound-DnaA) was oligomeric, primarily dimeric. Functional studies using DnaA mutants revealed that DnaA(H136Q) is defective in initiating replication in vivo. The mutant retains high-affinity ATP binding, but was defective in producing replication-competent initiation complexes. Docking of ATP on a structure of E. coli DnaA, modeled upon the crystallographic structure of Aquifex aeolicus DnaA, predicts a hydrogen bond between ATP and imidazole ring of His136, which is disrupted when Gln is present at position 136. SAXS performed on AMP-PNP-DnaA (H136Q) indicates that the protein has lost its ability to form oligomers. These results show the importance of high ATP in DnaA oligomerization and its dependence on the His136 residue.


Asunto(s)
Adenosina Difosfato/química , Adenosina Trifosfato/química , Proteínas Bacterianas/química , Replicación del ADN , ADN Bacteriano/genética , Proteínas de Unión al ADN/química , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Adenilil Imidodifosfato/química , Adenilil Imidodifosfato/metabolismo , Aquifex , Bacterias/genética , Bacterias/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Cromosomas Bacterianos/química , Cromosomas Bacterianos/metabolismo , Cristalografía por Rayos X , ADN Bacteriano/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Dimerización , Escherichia coli/metabolismo , Enlace de Hidrógeno , Simulación del Acoplamiento Molecular , Mutación , Plásmidos/química , Plásmidos/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Origen de Réplica , Termodinámica
4.
PLoS Genet ; 14(5): e1007426, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29795553

RESUMEN

Initiation of chromosome replication in bacteria is precisely timed in the cell cycle. Bacteria that harbor multiple chromosomes face the additional challenge of orchestrating replication initiation of different chromosomes. In Vibrio cholerae, the smaller of its two chromosomes, Chr2, initiates replication after Chr1 such that both chromosomes terminate replication synchronously. The delay is due to the dependence of Chr2 initiation on the replication of a site, crtS, on Chr1. The mechanism by which replication of crtS allows Chr2 replication remains unclear. Here, we show that blocking Chr1 replication indeed blocks Chr2 replication, but providing an extra crtS copy in replication-blocked Chr1 permitted Chr2 replication. This demonstrates that unreplicated crtS copies have significant activity, and suggests that a role of replication is to double the copy number of the site that sufficiently increases its activity for licensing Chr2 replication. We further show that crtS activity promotes the Chr2-specific initiator function and that this activity is required in every cell cycle, as would be expected of a cell-cycle regulator. This study reveals how increase of gene dosage through replication can be utilized in a critical regulatory switch.


Asunto(s)
Proteínas Bacterianas/genética , Cromosomas Bacterianos/genética , ADN Bacteriano/genética , Dosificación de Gen , Vibrio cholerae/genética , División Celular/genética , Replicación del ADN/genética , Regulación Bacteriana de la Expresión Génica , Origen de Réplica
5.
BMC Neurol ; 20(1): 286, 2020 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-32718330

RESUMEN

BACKGROUND: Central sensitization is thought to be an important contributing factor in many chronic pain disorders. The Central Sensitization Inventory (CSI) is a patient-reported measure frequently used to assess symptoms related to central sensitization. The aims of the study were to translate and cross-culturally adapt the CSI into Nepali (CSI-NP) and assess its measurement properties. METHODS: The CSI was translated into Nepali using recommended guidelines. The CSI-NP was then administered on 100 Nepalese adults with sub-acute and chronic musculoskeletal pain with additional demographic and pain-related questions. The CSI-Nepali was administered again about 2 weeks later. Four measurement properties of the CSI-NP were evaluated: (1) internal consistency using Cronbach's alpha, (2) test-retest reliability using intraclass correlation coefficient (ICC2,1), (3) measurement errors, and (4) construct validity testing five a priori hypotheses. Confirmation of construct validity was determined if a minimum of 75% of the hypotheses were met. RESULTS: The CSI was successfully translated into Nepali. Internal consistency and test-retest reliability were both excellent (Cronbach's alpha = 0.91, and ICC = 0.98). The standard error of measurement was 0.31 and the smallest detectable change was 0.86. Four out of five (80%) a priori hypotheses were met, confirming the construct validity: the CSI-NP correlated strongly with the Pain Catastrophizing Scale total scores (r = 0.50); moderately with the total number of pain descriptors (r = 0.35); weakly with the Numerical Rating Scale (r = 0.25); and women had significantly higher CSI scores than men. However, the CSI scores did not correlate significantly with the total duration of pain, as hypothesized (r = 0.10). CONCLUSIONS: The Nepali translation of the CSI demonstrated excellent reliability and construct validity in adults with musculoskeletal pain. It is now available to Nepali health care providers to help assess central sensitization-related signs and symptoms in individuals with musculoskeletal pain in research or clinical practice to advance the understanding of central sensitization in Nepalese samples.


Asunto(s)
Catastrofización/fisiopatología , Sensibilización del Sistema Nervioso Central/fisiología , Comparación Transcultural , Dolor Musculoesquelético/fisiopatología , Psicometría , Traducciones , Adulto , Catastrofización/complicaciones , Femenino , Humanos , Estudios Longitudinales , Masculino , Dolor Musculoesquelético/complicaciones , Nepal , Dimensión del Dolor/métodos , Reproducibilidad de los Resultados , Autoinforme
6.
J Cell Mol Med ; 22(9): 4274-4282, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29971909

RESUMEN

Allogeneic stem cell transplantation is currently the only curative therapy for primary myelofibrosis (MF), while the JAK2 inhibitor, ruxolitinib. Has been approved only for palliation. Other therapies are desperately needed to reverse life-threatening MF. However, the cell(s) and cytokine(s) that promote MF remain unclear. Several reports have demonstrated that captopril, an inhibitor of angiotensin-converting enzyme that blocks the production of angiotensin II (Ang II), mitigates fibrosis in heart, lung, skin and kidney. Here, we show that captopril can mitigate the development of MF in the Gata1low mouse model of primary MF. Gata1low mice were treated with 79 mg/kg/d captopril in the drinking water from 10 to 12 months of age. At 13 months of age, bone marrows were examined for fibrosis, megakaryocytosis and collagen expression; spleens were examined for megakaryocytosis, splenomegaly and collagen expression. Treatment of Gata1low mice with captopril in the drinking water was associated with normalization of the bone marrow cellularity; reduced reticulin fibres, splenomegaly and megakaryocytosis; and decreased collagen expression. Our findings suggest that treating with the ACE inhibitors captopril has a significant benefit in overcoming pathological changes associated with MF.


Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Antineoplásicos/farmacología , Captopril/farmacología , Factor de Transcripción GATA1/genética , Mielofibrosis Primaria/tratamiento farmacológico , Esplenomegalia/tratamiento farmacológico , Administración Oral , Animales , Médula Ósea/efectos de los fármacos , Médula Ósea/metabolismo , Médula Ósea/patología , Colágeno/antagonistas & inhibidores , Colágeno/genética , Colágeno/metabolismo , Modelos Animales de Enfermedad , Agua Potable/administración & dosificación , Reposicionamiento de Medicamentos , Femenino , Factor de Transcripción GATA1/deficiencia , Expresión Génica , Masculino , Megacariocitos/efectos de los fármacos , Megacariocitos/metabolismo , Megacariocitos/patología , Ratones , Ratones Noqueados , Mielofibrosis Primaria/genética , Mielofibrosis Primaria/metabolismo , Mielofibrosis Primaria/patología , Reticulina/antagonistas & inhibidores , Reticulina/genética , Reticulina/metabolismo , Esplenomegalia/genética , Esplenomegalia/metabolismo , Esplenomegalia/patología
7.
Nucleic Acids Res ; 42(16): 10538-49, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25159619

RESUMEN

RctB, the initiator of replication of Vibrio cholerae chromosome 2 (chr2), binds to the origin of replication to specific 12-mer sites both as a monomer and a dimer. Binding to 12-mers is essential for initiation. The monomers also bind to a second kind of site, 39-mers, which inhibits initiation. Mutations in rctB that reduce dimer binding increase monomer binding to 12-mers but decrease monomer binding to 39-mers. The mechanism of this paradoxical binding behavior has been unclear. Using deletion and alanine substitution mutants of RctB, we have now localized to a 71 amino acid region residues important for binding to the two kinds of DNA sites and for RctB dimerization. We find that the dimerization domain overlaps with both the DNA binding domains, explaining how changes in the dimerization domain can alter both kinds of DNA binding. Moreover, dimerization-defective mutants could be initiation-defective without apparent DNA binding defect. These results suggest that dimerization might be important for initiation beyond its role in controlling DNA binding. The finding that determinants of crucial initiator functions reside in a small region makes the region an attractive target for anti-V. cholerae drugs.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Cromosomas Bacterianos , Replicación del ADN , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Vibrio cholerae/genética , ADN/biosíntesis , ADN/metabolismo , Unión Proteica , Multimerización de Proteína , Estructura Terciaria de Proteína
8.
Physiol Plant ; 154(4): 543-59, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25302555

RESUMEN

The predicted increase in the frequency and magnitude of extreme heat spikes under future climate can reduce rice yields significantly. Rice sensitivity to high temperatures during the reproductive stage is well documented while the same during the vegetative stage is more speculative. Hence, to identify and characterize novel heat-tolerant donors for both the vegetative and reproductive stages, 71 rice accessions, including approximately 75% New Rice for Africa (NERICAs), were phenotyped across field experiments during summer seasons in Delhi, India, and in a controlled environment study at International Rice Research Institute, Philippines. NERICA-L-44 (NL-44) recorded high seedling survival (52%) and superior growth and greater reproductive success exposed to 42.2°C (sd ± 2.3) under field conditions. NL-44 and the heat-tolerant check N22 consistently displayed lower membrane damage and higher antioxidant enzymes activity across leaves and spikelets. NL-44 recorded 50-60% spikelet fertility, while N22 recorded 67-79% under controlled environment temperature of 38°C (sd±1.17), although both had about 87% fertility under extremely hot field conditions. N22 and NL-44, exposed to heat stress (38°C), had similar pollen germination percent and number of pollen tubes reaching the ovary. NL-44 maintained low hydrogen peroxide production and non-photochemical quenching (NPQ) with high photosynthesis while N22 avoided photosystem II damage through high NPQ under high-temperature stress. NL-44 with its reproductive stage resilience to extreme heat stress, better antioxidant scavenging ability in both vegetative tissue and spikelets and superior yield and grain quality is identified as a novel donor for increasing heat tolerance at both the vegetative and reproductive stages in rice.


Asunto(s)
Adaptación Fisiológica , Calor , Oryza/fisiología , Proteínas de Plantas/fisiología , Antioxidantes/metabolismo , Clorofila/metabolismo , Flores/crecimiento & desarrollo , Estrés Oxidativo , Reproducción
9.
Nucleic Acids Res ; 40(13): 6026-38, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22447451

RESUMEN

The origin region of Vibrio cholerae chromosome II (chrII) resembles plasmid origins that have repeated initiator-binding sites (iterons). Iterons are essential for initiation as well as preventing over-initiation of plasmid replication. In chrII, iterons are also essential for initiation but over-initiation is prevented by sites called 39-mers. Both iterons and 39-mers are binding sites of the chrII specific initiator, RctB. Here, we have isolated RctB mutants that permit over-initiation in the presence of 39-mers. Characterization of two of the mutants showed that both are defective in 39-mer binding, which helps to explain their over-initiation phenotype. In vitro, RctB bound to 39-mers as monomers, and to iterons as both monomers and dimers. Monomer binding to iterons increased in both the mutants, suggesting that monomers are likely to be the initiators. We suggest that dimers might be competitive inhibitors of monomer binding to iterons and thus help control replication negatively. ChrII replication was found to be dependent on chaperones DnaJ and DnaK in vivo. The chaperones preferentially improved dimer binding in vitro, further suggesting the importance of dimer binding in the control of chrII replication.


Asunto(s)
Proteínas Bacterianas/metabolismo , Cromosomas Bacterianos/metabolismo , Replicación del ADN , Proteínas de Unión al ADN/metabolismo , Origen de Réplica , Vibrio cholerae/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Sitios de Unión , Cromosomas Bacterianos/química , ADN Bacteriano/química , ADN Bacteriano/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Dimerización , Chaperonas Moleculares/metabolismo , Mutación , Unión Proteica , Vibrio cholerae/metabolismo
10.
Biochim Biophys Acta ; 1819(7): 826-9, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22306663

RESUMEN

On the basis of limited information, bacteria were once assumed to have no more than one chromosome. In the era of genomics, it has become clear that some, like eukaryotes, have more than one chromosome. Multichromosome bacteria provide opportunities to investigate how split genomes emerged, whether the individual chromosomes communicate to coordinate their replication and segregation, and what selective advantages split genomes might provide. Our current knowledge of these topics comes mostly from studies in Vibrio cholerae, which has two chromosomes, chr1 and chr2. Chr1 carries out most of the house-keeping functions and is considered the main chromosome, whereas chr2 appears to have originated from a plasmid and has acquired genes of mostly unknown origin and function. Nevertheless, unlike plasmids, chr2 replicates once and only once per cell cycle, like a bona fide chromosome. The two chromosomes replicate and segregate using separate programs, unlike eukaryotic chromosomes. They terminate replication synchronously, suggesting that there might be communication between them. Replication of the chromosomes is affected by segregation genes but in a chromosome specific fashion, a new development in the field of DNA replication control. The split genome allows genome duplication to complete in less time and with fewer replication forks, which could be beneficial for genome maintenance during rapid growth, which is the norm for V. cholerae in broth cultures and in the human host. In the latter, the expression of chr2 genes increases preferentially. Studies of chromosome maintenance in multichromosomal bacteria, although in their infancy, are already broadening our view of chromosome biology. This article is part of a Special Issue entitled: Chromatin in time and space.


Asunto(s)
Bacterias/genética , Cromosomas Bacterianos/metabolismo , ADN Bacteriano/genética , Segregación Cromosómica , Cromosomas Bacterianos/genética , Replicación del ADN , ADN Bacteriano/metabolismo , Regulación Bacteriana de la Expresión Génica , Genoma Bacteriano , Humanos
11.
Plant Cell Rep ; 31(2): 271-9, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21996937

RESUMEN

The rice Ubiquitin1 (Ubi1) promoter was tested to evaluate its capacity to express the heterologous gusA gene encoding ß-glucuronidase in transgenic rice tissue relative to the commonly used Ubi1 corn promoter and the rice gibberellic acid insensitive (GAI) gene promoter element. Experimental results showed increased expression of gusA gene in rice tissue when driven by the native Ubi1 promoter when compared to the use of corn Ubi1 promoter. Results further indicated that the cis-regulatory elements present in the native promoter element might have been responsible for high expression. However, the gusA gene expression level when driven by the rice GAI promoter was notably lower than both Ubi1 promoters. The present study, thus, for the first time helped to demonstrate that the native Ubi1 promoter is a promising genetic element in transgenic approaches for constitutive expression of any gene in rice tissue.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Oryza/genética , Poliubiquitina/genética , Regiones Promotoras Genéticas/genética , Análisis de Varianza , Southern Blotting , Western Blotting , Clonación Molecular , Cruzamientos Genéticos , ADN de Plantas/genética , Fluorometría , Glucuronidasa/genética , Glucuronidasa/metabolismo , Plantas Modificadas Genéticamente , Zea mays/metabolismo
12.
JNMA J Nepal Med Assoc ; 60(248): 364-368, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35633222

RESUMEN

Introduction: Preterm babies are born before 37 completed weeks of gestation. It is an important cause of neonatal morbidity and mortality. This study aimed to find out the prevalence of neonatal intensive care unit admissions among preterm babies in a tertiary care centre. Methods: A descriptive cross-sectional study on a total of 133 preterm infants was conducted in a tertiary care centre from November, 2020 to April, 2021 with ethical approval from the Institutional Review Committee (Reference number: 380). Preterm babies who met the eligibility criteria were included in the study. Convenience sampling was done. Data were analysed using the Statistical Package for the Social Sciences version 20.0. Point estimate at 95% Confidence Interval was calculated along with frequency and percentage for binary data. Results: Out of 133 preterm babies, 54 (40.60%) (32.25-48.95 at 95% Confidence Interval) had neonatal intensive care unit admissions. Hyaline membrane disease was the most common illness in preterm neonates 34 (62.96%) followed by neonatal sepsis 20 (37.03%). Conclusions: The prevalence of neonatal intensive care unit admissions among preterm babies in our study was similar to other studies done in similar settings. Preterm newborns are significantly vulnerable and maternal risk factors should be taken into account. Anticipated preterm deliveries should have mandatory institutional delivery and adequate postnatal care is needed to improve the outcomes of preterm babies. Keywords: morbidity; mortality; neonatal intensive care unit; preterm infants.


Asunto(s)
Enfermedades del Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Estudios Transversales , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Centros de Atención Terciaria
13.
J Nepal Health Res Counc ; 19(1): 62-65, 2021 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-33934134

RESUMEN

BACKGROUND: The study is aimed at highlighting the pattern of congenital defect in a tertiary care hospital. Congenital anomalies are recognized as a growing cause of neonatal morbidity and mortality in developing countries and a major cause of distress to parents. METHODS: This was a prospective descriptive study conducted between September 2019 and August 2020 with the objective to determine the types of congenital anomalies among live born neonates at Manipal Teaching Hospital (MTH), Pokhara and to determine their immediate outcome. Neonatal and maternal characteristics were noted. RESULTS: Twenty four out of 2515 live births had congenital anomalies during the study period, giving an incidence rate of 9.42 congenital anomalies per 1000 live birth per year. Single system involvement was seen in 79.2 % cases, remaining 5 (20.8%) neonates had involvement of more than one system; 54.2% of these newborns were discharged, 33.3% expired, 8.3% left against medical advice and 4.2% were referred out. CONCLUSIONS: This study highlights the importance of clinical examination of neonates to detect anomalies in our setting.


Asunto(s)
Anomalías Congénitas , Anomalías Congénitas/epidemiología , Humanos , Incidencia , Recién Nacido , Nepal/epidemiología , Estudios Prospectivos
14.
Science ; 373(6558): 1040-1046, 2021 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-34446607

RESUMEN

The antitumor efficacy of cancer immunotherapy can correlate with the presence of certain bacterial species within the gut microbiome. However, many of the molecular mechanisms that influence host response to immunotherapy remain elusive. In this study, we show that members of the bacterial genus Enterococcus improve checkpoint inhibitor immunotherapy in mouse tumor models. Active enterococci express and secrete orthologs of the NlpC/p60 peptidoglycan hydrolase SagA that generate immune-active muropeptides. Expression of SagA in nonprotective E. faecalis was sufficient to promote immunotherapy response, and its activity required the peptidoglycan sensor NOD2. Notably, SagA-engineered probiotics or synthetic muropeptides also augmented anti-PD-L1 antitumor efficacy. Taken together, our data suggest that microbiota species with specialized peptidoglycan remodeling activity and muropeptide-based therapeutics may enhance cancer immunotherapy and could be leveraged as next-generation adjuvants.


Asunto(s)
Antígeno B7-H1/antagonistas & inhibidores , Enterococcus/metabolismo , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Melanoma Experimental/terapia , N-Acetil Muramoil-L-Alanina Amidasa/metabolismo , Peptidoglicano/metabolismo , Animales , Carga Bacteriana , Proteínas Bacterianas/metabolismo , Enterococcus/enzimología , Enterococcus faecalis/metabolismo , Enterococcus faecium/metabolismo , Microbioma Gastrointestinal , Inmunoterapia , Melanoma Experimental/inmunología , Ratones , Ratones Endogámicos C57BL , Proteína Adaptadora de Señalización NOD2/metabolismo , Fragmentos de Péptidos/metabolismo , Probióticos , Transducción de Señal
15.
Biomedicines ; 9(9)2021 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-34572293

RESUMEN

Inflammatory bowel disease (IBD) is characterized by gastrointestinal inflammation comprised of Crohn's disease and ulcerative colitis. Centers for Disease Control and Prevention report that 1.3% of the population of the United States (approximately 3 million people) were affected by the disease in 2015, and the number keeps increasing over time. IBD has a multifactorial etiology, from genetic to environmental factors. Most of the IBD treatments revolve around disease management, by reducing the inflammatory signals. We previously identified the surface layer protein A (SlpA) of Lactobacillus acidophilus that possesses anti-inflammatory properties to mitigate murine colitis. Herein, we expressed SlpA in a clinically relevant, food-grade Lactococcus lactis to further investigate and characterize the protective mechanisms of the actions of SlpA. Oral administration of SlpA-expressing L. lactis (R110) mitigated the symptoms of murine colitis. Oral delivery of R110 resulted in a higher expression of IL-27 by myeloid cells, with a synchronous increase in IL-10 and cMAF in T cells. Consistent with murine studies, human dendritic cells exposed to R110 showed exquisite differential gene regulation, including IL-27 transcription, suggesting a shared mechanism between the two species, hence positioning R110 as potentially effective at treating colitis in humans.

16.
Health Phys ; 119(6): 746-757, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32384373

RESUMEN

The molecule 3,3'-diindolylmethane (DIM) is small, a major bioactive metabolite of indole-3 carbinol (13C), and a phytochemical compound from cruciferous vegetables released upon exposure to the gut acid environment. DIM is a proposed anti-cancer agent and was previously demonstrated to prevent radiation damage in the bone marrow and the gastrointestinal tract. Here we investigated the effect of DIM on radiation-induced injury to the lung in a murine model through untargeted metabolomics and gene expression studies of select genes. CBA mice were exposed to thoracic irradiation (17.5 Gy). Mice were treated with vehicle or DIM (250 mg kg, subcutaneous injection) on days -1 pre-irradiation through +14 post-irradiation. DIM induced a significant improvement in survival by day 150 post-irradiation. Fibrosis-related gene expression and metabolomics were examined using lung tissue from days 15, 45, 60, 90, and 120 post-irradiation. Our qRT-PCR experiments showed that DIM treatment reduced radiation-induced late expression of collagen Iα and the cell cycle checkpoint proteins p21/waf1 (CDKN1A) and p16ink (CDKN2A). Metabolomic studies of lung tissue demonstrated a significant dampening of radiation-induced changes following DIM treatment. Metabolites associated with pro-inflammatory responses and increased oxidative stress, such as fatty acids, were suppressed by DIM treatment compared to irradiated samples. Together these data suggest that DIM reduces radiation-induced sequelae in the lung.


Asunto(s)
Anticarcinógenos/farmacología , Indoles/farmacología , Lesión Pulmonar/tratamiento farmacológico , Traumatismos Experimentales por Radiación/tratamiento farmacológico , Tórax/efectos de la radiación , Rayos X/efectos adversos , Animales , Femenino , Lesión Pulmonar/etiología , Lesión Pulmonar/patología , Ratones , Ratones Endogámicos CBA , Traumatismos Experimentales por Radiación/etiología , Traumatismos Experimentales por Radiación/patología
17.
Sci Rep ; 9(1): 2198, 2019 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-30778109

RESUMEN

The increasing potential for accidental radiation exposure from either nuclear accidents or terrorist activities has escalated the need for radiation countermeasure development. We previously showed that a 30-day course of high-dose captopril, an ACE inhibitor, initiated 1-4 h after total body irradiation (TBI), improved Hematopoietic Acute Radiation Syndrome (H-ARS) and increased survival in mice. However, because of the time likely required for the deployment of a stockpiled radiation countermeasure to a radiation mass casualty site, there is a need for therapies that can be administered 24-48 hours after initial exposure. Using C57BL/6 mice exposed to an LD50-80/30 of 60Co TBI (7.75-7.9 Gy, 0.615 Gy/min), we show that low-dose captopril administration, initiated as late as 48 h post-TBI and continued for 14 days, significantly enhanced overall survival similarly to high-dose, rapid administration. Captopril treatment did not affect radiation-induced cell cycle arrest genes or the immediate loss of hematopoietic precursors. Reduced mortality was associated with the recovery of bone marrow cellularity and mature blood cell recovery at 21-30 days post-irradiation. Captopril reduced radiation-induced cytokines EPO, G-CSF, and SAA in the plasma. Finally, delayed captopril administration mitigated brain micro-hemorrhage at 21 days post-irradiation. These data indicate that low dose captopril administered as late as 48 h post-TBI for only two weeks improves survival that is associated with hematopoietic recovery and reduced inflammatory response. These data suggest that captopril may be an ideal countermeasure to mitigate H-ARS following accidental radiation exposure.


Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/administración & dosificación , Captopril/administración & dosificación , Hematopoyesis/efectos de los fármacos , Hematopoyesis/efectos de la radiación , Protectores contra Radiación/administración & dosificación , Irradiación Corporal Total , Síndrome de Radiación Aguda/sangre , Síndrome de Radiación Aguda/etiología , Síndrome de Radiación Aguda/mortalidad , Síndrome de Radiación Aguda/prevención & control , Animales , Recuento de Células Sanguíneas , Ciclo Celular/efectos de los fármacos , Ciclo Celular/efectos de la radiación , Citocinas/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/efectos de la radiación , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/efectos de la radiación , Mediadores de Inflamación/metabolismo , Ratones , Dosis de Radiación , Exposición a la Radiación , Tiempo de Tratamiento , Irradiación Corporal Total/efectos adversos
18.
J Pain Res ; 11: 2385-2396, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30425551

RESUMEN

BACKGROUND: Both socioeconomic and psychological factors have been shown to predict patient function in samples of individuals with chronic pain in Western countries. However, little is known about their role as predictors of function in individuals with chronic pain from developing countries. PURPOSE: The purpose of this study was to examine the associations between measures of socioeconomic factors (income, education) and psychological factors (catastrophizing and resilience) and measures of function in a sample of individuals with chronic pain from rural Nepal. In addition, we sought to evaluate the moderating effects of socioeconomic factors on the associations between the psychological variables and function. METHODS: We interviewed 143 adults with chronic musculoskeletal pain from rural areas of Nepal to assess income, education level, pain intensity, catastrophizing, resilience, physical function, and depression. We performed two regression analyses to evaluate the direct and unique effects of the socioeconomic and psychological variables and pain intensity as predictors of patient function, as well as the moderating influence of income, education level, and pain intensity on the associations between the psychological variables and function. RESULTS: Education and income both predicted physical function, but only income predicted depression. In addition, pain catastrophizing, but not resilience, evidenced a direct and significant independent association with depression. Neither catastrophizing nor resilience made independent and significant direct contributions to the prediction of physical function. The association between resilience and physical function was moderated by pain intensity and income, and income (but not education or pain intensity) moderated the associations between both 1) resilience and depression and 2) catastrophizing and depression. CONCLUSION: The results suggest the possibility that cultural differences may influence the role that psychosocial factors play in chronic pain adjustment. These findings have important implications regarding how psychosocial pain interventions should be adapted by individuals in developing countries.

19.
Elife ; 72018 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-30277210

RESUMEN

Binary fission has been well studied in rod-shaped bacteria, but the mechanisms underlying cell division in spherical bacteria are poorly understood. Rod-shaped bacteria harbor regulatory proteins that place and remodel the division machinery during cytokinesis. In the spherical human pathogen Staphylococcus aureus, we found that the essential protein GpsB localizes to mid-cell during cell division and co-constricts with the division machinery. Depletion of GpsB arrested cell division and led to cell lysis, whereas overproduction of GpsB inhibited cell division and led to the formation of enlarged cells. We report that S. aureus GpsB, unlike other Firmicutes GpsB orthologs, directly interacts with the core divisome component FtsZ. GpsB bundles and organizes FtsZ filaments and also stimulates the GTPase activity of FtsZ. We propose that GpsB orchestrates the initial stabilization of the Z-ring at the onset of cell division and participates in the subsequent remodeling of the divisome during cytokinesis.


Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas del Citoesqueleto/metabolismo , Staphylococcus aureus/metabolismo , Factores de Virulencia/metabolismo , Proteínas Bacterianas/genética , División Celular/genética , Proteínas del Citoesqueleto/genética , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Genes Esenciales/genética , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Hidrólisis , Microscopía Fluorescente , Unión Proteica , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Imagen de Lapso de Tiempo/métodos , Factores de Virulencia/genética
20.
Plant Physiol Biochem ; 45(6-7): 490-500, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17466529

RESUMEN

Acyl carrier protein (ACP) is a central cofactor for de novo fatty acid synthesis, acyl chain modification and chain-length termination during lipid biosynthesis in living organisms. Although the structural and functional organization of the ACPs in bacteria and plant are highly conserved, the individual ACP is engaged in the generation of sets of signature fatty acids required for specific purpose in bacterial cells and plant tissues. Realizing the fact that the bacterial ACP being originated early in molecular evolution is characteristically different from the plant's counterpart, we explored the property of an ACP from Azospirillum brasilense (Ab), a plant-associative aerobic bacterium, to find its role in changing the fatty acid profile in heterologous systems. Functional expression of Ab-ACP in Escherichia coli, an enteric bacterium, and Brassica juncea, an oil-seed crop plant, altered the fatty acid composition having predominantly 18-carbon acyl pool, reflecting the intrinsic nature of the ACP from A. brasilense which usually has C18:1 rich membrane lipid. In transgenic Brassica the prime increment was found for C18:3 in leaves; and C18:1 and C8:2 in seeds. Interestingly, the seed oil quality of the transgenic Brassica potentially improved for edible purposes, particularly with respect to the enhancement in the ratio of monounsaturated (C18:1)/saturated fatty acids, increment in the ratio of linoleic (C18:2)/linolenic (C18:3) and reduction of erucic acid (C22:1).


Asunto(s)
Proteína Transportadora de Acilo/genética , Azospirillum brasilense/genética , Brassica napus/genética , Escherichia coli/genética , Ácidos Grasos/metabolismo , Proteína Transportadora de Acilo/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Brassica napus/microbiología , Clonación Molecular , Isopropil Tiogalactósido/farmacología , Cinética , Datos de Secuencia Molecular , Plantas Modificadas Genéticamente/metabolismo , Proteínas Recombinantes/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA