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1.
EMBO J ; 36(17): 2488-2509, 2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-28694245

RESUMEN

The synaptonemal complex (SC) is a proteinaceous macromolecular assembly that forms during meiotic prophase I and mediates adhesion of paired homologous chromosomes along their entire lengths. Although prompt disassembly of the SC during exit from prophase I is a landmark event of meiosis, the underlying mechanism regulating SC destruction has remained elusive. Here, we show that DDK (Dbf4-dependent Cdc7 kinase) is central to SC destruction. Upon exit from prophase I, Dbf4, the regulatory subunit of DDK, directly associates with and is phosphorylated by the Polo-like kinase Cdc5. In parallel, upregulated CDK1 activity also targets Dbf4. An enhanced Dbf4-Cdc5 interaction pronounced phosphorylation of Dbf4 and accelerated SC destruction, while reduced/abolished Dbf4 phosphorylation hampered destruction of SC proteins. SC destruction relieved meiotic inhibition of the ubiquitous recombinase Rad51, suggesting that the mitotic recombination machinery is reactivated following prophase I exit to repair any persisting meiotic DNA double-strand breaks. Taken together, we propose that the concerted action of DDK, Polo-like kinase, and CDK1 promotes efficient SC destruction at the end of prophase I to ensure faithful inheritance of the genome.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas Fúngicas/metabolismo , Meiosis/fisiología , Proteínas Quinasas/metabolismo , Complejo Sinaptonémico/metabolismo , Fosforilación , Saccharomycetales/metabolismo
2.
Health Commun ; 36(14): 1825-1840, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-32731759

RESUMEN

Primary Caregivers are the fulcrum in the physician-caregiver-child triad. Existing literature discusses static multi-component interventions in detail. In long-term treatments, dynamic intervention design is needed as the environment and situations of the families are dynamic. The objectives of this study are (a) to identify the components of the primary caregiver's perception of the physician's value with reference to the effectiveness of consultation and relationships with the former and with the child; (b) to establish the role of this perception in designing dynamic interventions, and (c) to describe the perception's potential influence on adherence. A PRISMA, chronological, and morphological analysis of the literature is carried out about caregivers' adherence in the pediatric long-term treatment context. We define communication and consultation as the functional, whereas relationship as the emotional component of the caregiver's perception of the physician. We propose a theoretical model that incorporates intervention as an integral component of care. Adherence happens as a response to changing situations and hence fluctuates. Hence, a dynamic intervention design to benefit the child should be incorporated into care through the caregiver-physician bridge. Future research should explore how intervention needs change and the driving reasons for understanding the static and dynamic components of interventions.


Asunto(s)
Cuidadores , Médicos , Comunicación , Familia , Humanos
3.
PLoS Biol ; 14(2): e1002369, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26870961

RESUMEN

Faithful meiotic chromosome segregation and fertility require meiotic recombination between homologous chromosomes rather than the equally available sister chromatid, a bias that in Saccharomyces cerevisiae depends on the meiotic kinase, Mek1. Mek1 is thought to mediate repair template bias by specifically suppressing sister-directed repair. Instead, we found that when Mek1 persists on closely paired (synapsed) homologues, DNA repair is severely delayed, suggesting that Mek1 suppresses any proximal repair template. Accordingly, Mek1 is excluded from synapsed homologues in wild-type cells. Exclusion requires the AAA+-ATPase Pch2 and is directly coupled to synaptonemal complex assembly. Stage-specific depletion experiments further demonstrate that DNA repair in the context of synapsed homologues requires Rad54, a repair factor inhibited by Mek1. These data indicate that the sister template is distinguished from the homologue primarily by its closer proximity to inhibitory Mek1 activity. We propose that once pairing or synapsis juxtaposes homologues, exclusion of Mek1 is necessary to avoid suppression of all templates and accelerate repair progression.


Asunto(s)
Emparejamiento Cromosómico , Reparación del ADN , MAP Quinasa Quinasa 1/metabolismo , Roturas del ADN de Doble Cadena , ADN Helicasas/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Meiosis , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
4.
PLoS Genet ; 11(6): e1005335, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26114667

RESUMEN

Accurate chromosome segregation during meiosis relies on the presence of crossover events distributed among all chromosomes. MutSγ and MutLγ homologs (Msh4/5 and Mlh1/3) facilitate the formation of a prominent group of meiotic crossovers that mature within the context of an elaborate chromosomal structure called the synaptonemal complex (SC). SC proteins are required for intermediate steps in the formation of MutSγ-MutLγ crossovers, but whether the assembled SC structure per se is required for MutSγ-MutLγ-dependent crossover recombination events is unknown. Here we describe an interspecies complementation experiment that reveals that the mature SC is dispensable for the formation of Mlh3-dependent crossovers in budding yeast. Zip1 forms a major structural component of the budding yeast SC, and is also required for MutSγ and MutLγ-dependent crossover formation. Kluyveromyces lactis ZIP1 expressed in place of Saccharomyces cerevisiae ZIP1 in S. cerevisiae cells fails to support SC assembly (synapsis) but promotes wild-type crossover levels in those nuclei that progress to form spores. While stable, full-length SC does not assemble in S. cerevisiae cells expressing K. lactis ZIP1, aggregates of K. lactis Zip1 displayed by S. cerevisiae meiotic nuclei are decorated with SC-associated proteins, and K. lactis Zip1 promotes the SUMOylation of the SC central element protein Ecm11, suggesting that K. lactis Zip1 functionally interfaces with components of the S. cerevisiae synapsis machinery. Moreover, K. lactis Zip1-mediated crossovers rely on S. cerevisiae synapsis initiation proteins Zip3, Zip4, Spo16, as well as the Mlh3 protein, as do the crossovers mediated by S. cerevisiae Zip1. Surprisingly, however, K. lactis Zip1-mediated crossovers are largely Msh4/Msh5 (MutSγ)-independent. This separation-of-function version of Zip1 thus reveals that neither assembled SC nor MutSγ is required for Mlh3-dependent crossover formation per se in budding yeast. Our data suggest that features of S. cerevisiae Zip1 or of the assembled SC in S. cerevisiae normally constrain MutLγ to preferentially promote resolution of MutSγ-associated recombination intermediates.


Asunto(s)
Intercambio Genético , Proteínas Fúngicas/genética , Kluyveromyces/genética , Meiosis , Secuencia de Aminoácidos , Secuencia de Bases , Centrómero/genética , Segregación Cromosómica , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas Fúngicas/metabolismo , Prueba de Complementación Genética , Datos de Secuencia Molecular , Proteínas MutL , Proteína MutS de Unión a los Apareamientos Incorrectos del ADN/genética , Proteína MutS de Unión a los Apareamientos Incorrectos del ADN/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Homología de Secuencia de Aminoácido , Complejo Sinaptonémico/genética , Complejo Sinaptonémico/metabolismo
5.
Neurol India ; 65(5): 1019-1024, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28879889

RESUMEN

OBJECTIVES: Assessment of quality of life (QOL) reveals the impact of diseases and factors responsible for the impairment of quality of life. The purpose of this study was to evaluate the QOL among adolescents with epilepsy (AWE) in the state of Andhra Pradesh. MATERIALS AND METHODS: One hundred and fifty AWE aged 13-19 years were evaluated for QOL using the Telugu version of the Quality of Life in Epilepsy Inventory for Adolescents (QOLIE) AD-48 and the data were analyzed to predict the factors responsible for determining the QOL. RESULTS: The mean age of AWE was 15.86 ± 2.14 years. The age at onset of seizures among AWE was 9.28 ± 4.90 years. Generalized (45%) and partial seizures (34%) were the predominant types of seizures. The majority of AWE (77%) were taking anti epileptic medication for 1-8 years, were on monotherapy (55%), and were seizure free for the last 1 year (56%). The mean total QOL score in AWE was 72 ± 15. The high school-educated, seizure-free, and monotherapy-taking AWEs showed a significantly higher mean total QOL when compared to the primary school- educated, seizure-frequent, and polytherapy-taking AWEs (P < 0.01). Education (standardized beta [Sß] = 0.163 P < 0.05), seizure frequency (Sß-0.603; P < 0.01), and poly therapy (Sß-0.08; P < 0.01) were significant predictors of QOL in AWE. CONCLUSIONS: The results of the study suggest that in addition to seizure control, encouraging monotherapy and enhancing the education level may improve the QOL in AWE.


Asunto(s)
Epilepsia/psicología , Calidad de Vida , Adolescente , Edad de Inicio , Femenino , Humanos , India , Masculino , Encuestas y Cuestionarios , Adulto Joven
6.
J Neuroinflammation ; 12: 113, 2015 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-26048285

RESUMEN

BACKGROUND: The present study was proposed to elucidate the prophylactic role of curcumin in the prevention of hypoxia-induced cerebral edema (HACE). METHODS: Rats were exposed to simulated hypobaric hypoxia at 7620 m for 24 h at 25 ± 1 °C. Transvascular leakage, expression of transcriptional factors (nuclear factor-kappa B (NF-κB) and hypoxia inducible factor 1 alpha (Hif-1α) and also the genes regulated by these transcriptional factors, sodium potassium-adenosine triphosphatase (Na(+)/K(+)-ATPase) and endothelial sodium channel (ENaC) levels and brain tight junction (TJ) proteins like ZO-1, junctional adhesion molecule C (JAMC), claudin 4 and claudin 5 levels were determined in the brain of rats under hypoxia by Western blotting, electro mobility shift assay, ELISA, immunohistochemistry, and histopathology along with haematological parameters. Simultaneously, to rule out the fact that inflammation causes impaired Na(+)/K(+)-ATPase and ENaC functions and disturbing the TJ integrity leading to cerebral edema, the rats were pre-treated with curcumin (100 mg/kg body weight) 1 h prior to 24-h hypoxia. RESULTS: Curcumin administration to rats, under hypoxia showed a significant decrease (p < 0.001) in brain water content (3.53 ± 0.58 wet-to-dry-weight (W/D) ratio) and transvascular leakage (136.2 ± 13.24 relative fluorescence units per gram (r.f.u./g)) in the brain of rats compared to control (24-h hypoxia) (7.1 ± 1.0 W/D ratio and 262.42 ± 24.67 r.f.u./g, respectively). Curcumin prophylaxis significantly attenuated the upregulation of NF-κB (p < 0.001), thereby leading to concomitant downregulation of pro-inflammatory cytokine levels (↓IL-1, IL-2, IL-18 and TNF-α), cell adhesion molecules (↓P-selectin and E-selectin) and increased anti-inflammatory cytokine (↑IL-10). Curcumin stabilized the brain HIF-1α levels followed by maintaining VEGF levels along with upregulated Na(+)/K(+)-ATPase and ENaC levels (p < 0.001) under hypoxia. Curcumin restored the brain ZO-1, JAMC, claudin 4 and claudin 5 levels (p < 0.001) under hypoxia. Histopathological observations revealed the absence of edema and inflammation in the brain of rats supplemented with curcumin. CONCLUSIONS: These results indicate that curcumin is a potent drug in amelioration of HACE as it effectively attenuated inflammation as well as fluid influx by maintaining the tight junction proteins integrity with increased ion channels expression in the brain of rats under hypoxia.


Asunto(s)
Edema Encefálico/epidemiología , Edema Encefálico/prevención & control , Encéfalo/metabolismo , Curcumina/uso terapéutico , Hipoxia/complicaciones , Canales Iónicos/metabolismo , Proteínas de Uniones Estrechas/metabolismo , Animales , Barrera Hematoencefálica/efectos de los fármacos , Encéfalo/efectos de los fármacos , Edema Encefálico/metabolismo , Curcumina/farmacología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Canales Epiteliales de Sodio/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Incidencia , Masculino , FN-kappa B/metabolismo , Ratas , Ratas Sprague-Dawley , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Factores de Transcripción/metabolismo
7.
J Food Sci Technol ; 51(11): 3425-31, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26396341

RESUMEN

The present study was carried out to develop and evaluate ready to eat extruded snacks incorporated with garlic powder at various levels (5 %, 10 %, 15 %, 20 %). The organoleptic evaluation was conducted for the developed products and the well accepted products were selected for further studies like physical properties and shelf life (stored at room temperature for 2 months). The organoleptic evaluation of the developed snacks revealed that 15 % and 20 % garlic incorporated snacks were not acceptable due to strong garlic flavor, therefore T1 (control), T2 (5 % garlic) and T3 ( 10 % garlic) were selected for further studies. The physical properties showed significant changes with incorporation of garlic powder at 0 %-10 % level. There was an increase in mass flow rate, tap density and bulk density but decrease in the water holding capacity, oil absorption capacity and expansion ratio. The water soluble index and moisture retention of the products showed the same values for all the three selected treatments. The products were packed by ordinary, nitrogen and vacuum packing and stored for 2 months. It was found that there was an increase in moisture content and microbial load, however the increase was within limits. The increase in the moisture content was low in nitrogen packed products where as the microbial load decreased with increase in the percentage of garlic incorporation. The nitrogen and vacuum packed products showed less microbial load than the ordinary packed products. Garlic powder can be incorporated at 5 and 10 % levels in ready-to-eat extruded snacks with well acceptability and can be stored for a period of 2 months with nitrogen packing as an effective packaging.

8.
Sci Rep ; 14(1): 2091, 2024 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-38267448

RESUMEN

This study employs repeated, large panels of serological surveys to document rapid and substantial waning of SARS-CoV-2 antibodies at the population level and to calculate the extent to which infection and vaccination separately contribute to seroprevalence estimates. Four rounds of serological surveys were conducted, spanning two COVID waves (October 2020 and April-May 2021), in Tamil Nadu (population 72 million) state in India. Each round included representative populations in each district of the state, totaling ≥ 20,000 persons per round. State-level seroprevalence was 31.5% in round 1 (October-November 2020), after India's first COVID wave. Seroprevalence fell to 22.9% in round 2 (April 2021), a roughly one-third decline in 6 months, consistent with dramatic waning of SARS-Cov-2 antibodies from natural infection. Seroprevalence rose to 67.1% by round 3 (June-July 2021), with infections from the Delta-variant induced second COVID wave accounting for 74% of the increase. Seroprevalence rose to 93.1% by round 4 (December 2021-January 2022), with vaccinations accounting for 63% of the increase. Antibodies also appear to wane after vaccination. Seroprevalence in urban areas was higher than in rural areas, but the gap shrunk over time (35.7 v. 25.7% in round 1, 89.8% v. 91.4% in round 4) as the epidemic spread even in low-density rural areas.


Asunto(s)
COVID-19 , Humanos , India/epidemiología , COVID-19/epidemiología , COVID-19/prevención & control , SARS-CoV-2 , Estudios Seroepidemiológicos , Vacunación , Anticuerpos Antivirales
9.
Scand J Immunol ; 78(1): 92-7, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23654353

RESUMEN

Tuberculosis (TB) constitutes the major cause of death due to infectious diseases. Cytokines play a major role in defence against Mycobacterium tuberculosis infection. Polymorphisms in the genes encoding various cytokines have been associated with tuberculosis susceptibility. Household contacts (HHC) are at increased risk of developing the disease. In this study, we examined the association of IL-1ß and IL-10 cytokine gene polymorphisms with risk of developing tuberculosis in TB patients, their HHC and healthy controls (HC) using JavaStat and SPSS. Multifactor dimensionality reduction (MDR) analyses were performed to explore the potential gene-gene interactions. The genotype and allele frequencies of IL-1ß +3954C/T polymorphism did not vary significantly between TB patients and HC. GG (P < 0.005, OR = 0.219 and 95% CI = 0.059-0.735) and GA (P < 0.0001, OR = 2.938 and 95% CI = 1.526-5.696) genotypes of IL-10-1082 G/A polymorphism were found to be significantly associated with patients versus HC. HHC with CC (P < 0.03, OR = 1.833 and 95% CI = 1.1-3.35) genotype in IL-1ß and GA (P < 0.0001, OR = 4.612 and 95% CI = 2.225-9.702) genotype in IL-10 were at increased risk of developing tuberculosis. MDR tests revealed high-risk genotypes in IL-1ß and IL-10 based on the association model. Our results demonstrate that the polymorphisms of IL-1ß and IL-10 genes may be valuable markers to predict the risk for the development of TB in household contacts.


Asunto(s)
Predisposición Genética a la Enfermedad , Interleucina-10/genética , Interleucina-1beta/genética , Polimorfismo Genético , Adulto , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Tuberculosis/genética
10.
PLoS Genet ; 4(11): e1000263, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19008956

RESUMEN

In humans, meiotic chromosome segregation errors increase dramatically as women age, but the molecular defects responsible are largely unknown. Cohesion along the arms of meiotic sister chromatids provides an evolutionarily conserved mechanism to keep recombinant chromosomes associated until anaphase I. One attractive hypothesis to explain age-dependent nondisjunction (NDJ) is that loss of cohesion over time causes recombinant homologues to dissociate prematurely and segregate randomly during the first meiotic division. Using Drosophila as a model system, we have tested this hypothesis and observe a significant increase in meiosis I NDJ in experimentally aged Drosophila oocytes when the cohesin protein SMC1 is reduced. Our finding that missegregation of recombinant homologues increases with age supports the model that chiasmata are destabilized by gradual loss of cohesion over time. Moreover, the stage at which Drosophila oocytes are most vulnerable to age-related defects is analogous to that at which human oocytes remain arrested for decades. Our data provide the first demonstration in any organism that, when meiotic cohesion begins intact, the aging process can weaken it sufficiently and cause missegregation of recombinant chromosomes. One major advantage of these studies is that we have reduced but not eliminated the SMC1 subunit. Therefore, we have been able to investigate how aging affects normal meiotic cohesion. Our findings that recombinant chromosomes are at highest risk for loss of chiasmata during diplotene argue that human oocytes are most vulnerable to age-induced loss of meiotic cohesion at the stage at which they remain arrested for several years.


Asunto(s)
Envejecimiento/genética , Envejecimiento/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Predisposición Genética a la Enfermedad , Meiosis , No Disyunción Genética , Oocitos/metabolismo , Animales , Proteínas de Ciclo Celular/genética , Proteínas Cromosómicas no Histona/genética , Segregación Cromosómica , Intercambio Genético , Drosophila/genética , Drosophila/metabolismo , Femenino , Humanos , Modelos Animales , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Cohesinas
11.
Genetics ; 181(4): 1207-18, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19204374

RESUMEN

Normally, meiotic crossovers in conjunction with sister-chromatid cohesion establish a physical connection between homologs that is required for their accurate segregation during the first meiotic division. However, in some organisms an alternative mechanism ensures the proper segregation of bivalents that fail to recombine. In Drosophila oocytes, accurate segregation of achiasmate homologs depends on pairing that is mediated by their centromere-proximal heterochromatin. Our previous work uncovered an unexpected link between sister-chromatid cohesion and the fidelity of achiasmate segregation when Drosophila oocytes are experimentally aged. Here we show that a weak mutation in the meiotic cohesion protein ORD coupled with a reduction in centromere-proximal heterochromatin causes achiasmate chromosomes to missegregate with increased frequency when oocytes undergo aging. If ORD activity is more severely disrupted, achiasmate chromosomes with the normal amount of pericentric heterochromatin exhibit increased nondisjunction when oocytes age. Significantly, even in the absence of aging, a weak ord allele reduces heterochromatin-mediated pairing of achiasmate chromosomes. Our data suggest that sister-chromatid cohesion proteins not only maintain the association of chiasmate homologs but also play a role in promoting the physical association of achiasmate homologs in Drosophila oocytes. In addition, our data support the model that deterioration of meiotic cohesion during the aging process compromises the segregation of achiasmate as well as chiasmate bivalents.


Asunto(s)
Segregación Cromosómica/fisiología , Heterocromatina/fisiología , No Disyunción Genética/genética , Intercambio de Cromátides Hermanas/fisiología , Factores de Edad , Animales , Proteínas Portadoras/genética , Proteínas Portadoras/fisiología , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiología , Senescencia Celular/genética , Senescencia Celular/fisiología , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/fisiología , Emparejamiento Cromosómico/fisiología , Segregación Cromosómica/genética , Regulación hacia Abajo/genética , Drosophila/genética , Drosophila/fisiología , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiología , Femenino , Masculino , Modelos Biológicos , Oocitos/metabolismo , Oocitos/fisiología , Huso Acromático/fisiología , Cohesinas
12.
Curr Med Imaging Rev ; 15(2): 170-183, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31975663

RESUMEN

BACKGROUND: The sub-acute ischemic stroke is the most basic illnesses reason for death on the planet. We evaluate the impact of segmentation technique during the time of breaking down the capacities of the cerebrum. OBJECTIVE: The main objective of this paper is to segment the ischemic stroke lesions in Magnetic Resonance (MR) images in the presence of other pathologies like neurological disorder, encephalopathy, brain damage, Multiple sclerosis (MS). METHODS: In this paper, we utilize a hybrid way to deal with segment the ischemic stroke from alternate pathologies in magnetic resonance (MR) images utilizing Random Decision Forest (RDF) and Gravitational Search Algorithm (GSA). The RDF approach is an effective machine learning approach. RESULTS: The RDF strategy joins two parameters; they are; the number of trees in the forest and the number of leaves per tree; it runs quickly and proficiently when dealing with vast data. The GSA algorithm is utilized to optimize the RDF data for choosing the best number of trees and the number of leaves per tree in the forest. CONCLUSION: This paper provides a new hybrid GSA-RDF classifier technique to segment the ischemic stroke lesions in MR images. The experimental results demonstrate that the proposed technique has the Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), and Mean Bias Error (MBE) ranges are 16.5485 %, 7.2654 %, and 2.4585 %individually. The proposed RDF-GSA algorithm has better precision and execution when compared with the existing ischemic stroke segmentation method.


Asunto(s)
Algoritmos , Infarto Encefálico/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Árboles de Decisión , Aprendizaje Automático , Imagen por Resonancia Magnética/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Infarto Encefálico/complicaciones , Diagnóstico Diferencial , Humanos , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Accidente Cerebrovascular/etiología
14.
Nat Commun ; 10(1): 970, 2019 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-30814509

RESUMEN

Faithful meiotic chromosome inheritance and fertility rely on the stimulation of meiotic crossover recombination by potentially genotoxic DNA double-strand breaks (DSBs). To avoid excessive damage, feedback mechanisms down-regulate DSBs, likely in response to initiation of crossover repair. In Saccharomyces cerevisiae, this regulation requires the removal of the conserved DSB-promoting protein Hop1/HORMAD during chromosome synapsis. Here, we identify privileged end-adjacent regions (EARs) spanning roughly 100 kb near all telomeres that escape DSB down-regulation. These regions retain Hop1 and continue to break in pachynema despite normal synaptonemal complex deposition. Differential retention of Hop1 requires the disassemblase Pch2/TRIP13, which preferentially removes Hop1 from telomere-distant sequences, and is modulated by the histone deacetylase Sir2 and the nucleoporin Nup2. Importantly, the uniform size of EARs among chromosomes contributes to disproportionately high DSB and repair signals on short chromosomes in pachynema, suggesting that EARs partially underlie the curiously high recombination rate of short chromosomes.


Asunto(s)
Cromosomas Fúngicos/genética , Roturas del ADN de Doble Cadena , Meiosis/genética , Saccharomyces cerevisiae/genética , Telómero/genética , Emparejamiento Cromosómico/genética , Cromosomas Fúngicos/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Recombinación Genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas Reguladoras de Información Silente de Saccharomyces cerevisiae/metabolismo , Sirtuina 2/metabolismo , Telómero/metabolismo
15.
Toxicology ; 231(1): 1-10, 2007 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-17208344

RESUMEN

During early embryonic development, at blastocyst stage, the embryo has an outer coat of cells and an inner cell mass (ICM). ICM is the reservoir of embryonic stem (ES) cells, which are pluripotent, i.e., have the potential to differentiate into all cell types of the body. Cell lines have been developed from ES cells. In addition, there are embryonic germ (EG) cell lines developed from progenitor germ cells, and embryonic carcinoma (EC) cell lines developed from teratomas. These cell lines are being used for the study of basic and applied aspects in medical therapeutics, and disease management. Another potential of these cell lines is in the field of environmental mutagenesis. In addition to ES cells, there are adult stem cells in and around different organs and tissues of the body. It is now possible to grow pure populations of specific cell types from these adult stem cells. Treating specific cell types with chemical or physical agents and measuring their response offers a shortcut to test the toxicity in various organ systems in the adult organism. For example, to evaluate the genotoxicity of a chemical (e.g., drug or pesticide) or a physical agent (e.g., ionizing radiation or non-ionizing electromagnetic radiation) during embryonic development, a large number of animals are being used. As an alternative, use of stem cell lines would be a feasible proposition. Using stem cell lines, efforts are being made to standardize the protocols, which will not only be useful in testing the toxicity of a chemical or a physical agent, but also in the field of drug development, environmental mutagenesis, biomonitoring and other studies.


Asunto(s)
Células Madre Embrionarias/citología , Pruebas de Toxicidad/métodos , Toxicogenética/métodos , Diferenciación Celular , Línea Celular , Regulación del Desarrollo de la Expresión Génica , Humanos , Mutación
16.
Infect Genet Evol ; 6(3): 220-7, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16054876

RESUMEN

Bacterial isolates from respiratory and urinary tract infections in an Indian hospital setting were genotyped using FAFLP analysis. The 77 different isolates analyzed belonged to five genera namely Escherichia, Staphylococcus, Pseudomonas, Enterobacter and Pantoea. Before carrying out FAFLP analysis all the isolates were subjected to16S-23S ribosomal RNA-based species identification. Cluster analysis of FAFLP profiles of 77 isolates generated five groups corresponding to five bacterial genera that are used in the study. Further analyses of the dendrograms revealed efficient species and strain differentiation. Cluster analysis identified genetically distant clones among the clinical isolates of Staphylococcus aureus, two distinct genetic lineages among the Escherichia coli strains and a single cluster of closely related Pseudomonas aeruginosa isolates. Ribosomal spacer region amplification identified different species accurately but intraspecies discrimination could not be accomplished completely. Comparison of FAFLP profiles of our isolates, with a pilot database of validated strains, was very useful in identification and worked better in conjunction with dendrogram analysis.


Asunto(s)
ADN Bacteriano/análisis , Epidemiología Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Infección Hospitalaria , ADN Bacteriano/genética , Fluorescencia , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/genética , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/epidemiología , Infecciones por Bacterias Gramnegativas/genética , Infecciones por Bacterias Gramnegativas/microbiología , Hospitales , Humanos , India/epidemiología , Filogenia , Reacción en Cadena de la Polimerasa , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/genética , Infecciones del Sistema Respiratorio/microbiología , Especificidad de la Especie , Infecciones Urinarias/epidemiología , Infecciones Urinarias/genética , Infecciones Urinarias/microbiología
17.
J Environ Biol ; 27(2 Suppl): 459-60, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-17436544

RESUMEN

The ascorbic acid level was highest in immature proglottides and lowest in gravid proglottides of Avitellina lahorea, the gut parasite of sheep. The ascorbic acid content in all the regions of the parasite viz., immature, mature and gravid taken together remained higher to the value of the host serum. The above gradient between the parasite and the host serum interface suggested its active uptake on the part of the parasite.


Asunto(s)
Ácido Ascórbico/metabolismo , Sangre , Cestodos/metabolismo , Maduración Sexual , Animales , Ovinos
18.
Indian J Clin Biochem ; 20(2): 104-9, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23105541

RESUMEN

Alocholism is the multifactorial disease influenced by genetic environmental interaction and genetic variation of the genes may be associated with alcohol dependence due to its modified function in behavioral and physiological responses. In the present study, genetic variation was detected in the subtypes of gene, coding for the alcohol metabolizing enzyme Alcohol Dehydrogenase 2 (ADH2). Blood samples were collected from the alcoholic and non alcoholic subjects and genotyping was performed using PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism), analysis to determine genetic polymorphisms in the ADH2 gene subtypes. The three subtypes of ADH2 gene (ADH2.1, ADH2.2 and ADH2.3) were found in both alcoholics (Family History Positive and Family History Negative) as well as non alcoholics.

19.
J Assoc Physicians India ; 44(8): 521-4, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9251421

RESUMEN

During the year 1993-1994, 73 renal transplant cases have been screened for the presence of anti-HLA antibodies using the standard lymphocytotoxicity assay. Amongst the 9 related transplantations with 100% negative crossmatch 6 were successful. About 8.2% of the patients had a shift from positive to negative crossmatch. It was observed that an increased number of transfusions (ranging from 3 to 21) in males and females yielded negative crossmatches. In females, however, owing to various factors such as pregnancies, parity and infections, varied percentages were observed with different donors. The crossmatches in diabetics and hypertensive patients suggest no particular correlation and probably have no role in the outcome of the assay.


Asunto(s)
Prueba de Histocompatibilidad , Trasplante de Riñón/inmunología , Transfusión Sanguínea , Pruebas Inmunológicas de Citotoxicidad , Femenino , Antígenos HLA/inmunología , Humanos , Inmunización , Isoanticuerpos/análisis , Masculino , Embarazo
20.
Indian Pediatr ; 32(9): 979-82, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8935260

RESUMEN

The present study was conducted to evaluate and compare the specific cellular responses of children vaccinated with three different strains of BCG. The study comprised of normal children with normal weight and normal general responses (PHA) to in vitro leukocyte migration inhibition test (LMIT). The three strains of BCG under study were Japan-BCG, Glaxo-BCG and Madras-BCG. One hundred children were selected at random from each group. The mean ages of these infants were 9.9 +/- 9.5, 9.8 +/- 7.6 and 9.8 +/- 8.3 weeks, respectively. Six weeks after vaccination, the diameter (in mm) of induration at the vaccination site was measured. Three months after vaccination, in vitro LMIT was performed against PPD tuberculin antigen. This test was done again after 3 months in all the children who tested negative. The mean value of the diameter of the Glaxo-BCG group (10.0 +/- 13.5 mm) was significantly higher (p < 0.05) than the mean values of Japan-BCG (9.10 +/- 3.9 mm) and Madras-BCG (8.38 +/- 4.1 mm). The mean LMI values were similar in all the three groups. There was no correlation between the in vitro and in vivo parameters. The number of children positive to LMI (PPD) were 59, 58 and 63, for the Madras, Japan and Glaxo-BCG groups, respectively. A total number of 91, 91 and 95 were positive to LMIT at the end of 6 months after BCG in the Madras, Japan and Glaxo-BCG groups, respectively. The observations suggested that there were no major differences between the three strains of BCG in their capacity to induce cellular responses.


Asunto(s)
Vacuna BCG/clasificación , Tuberculosis , Vacunación , Análisis de Varianza , Vacuna BCG/administración & dosificación , Estudios de Evaluación como Asunto , Femenino , Humanos , Lactante , Masculino , Tuberculosis/inmunología , Tuberculosis/prevención & control
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