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1.
FASEB J ; 37(1): e22697, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36527387

RESUMEN

The properties and functions of BMSCs were altered by the diabetic microenvironment, and its mechanism was not very clear. In recent years, the regulation of the function of BMSCs by microRNA has become a research hotspot, meanwhile, HOX genes also have been focused on and involved in multiple functions of stem cells. In this study, we investigated the role of miR-139-5p in diabetes-induced BMSC impairment. Since HOXA9 may be a target gene of miR-139-5p, we speculated that miR-139-5p/HOXA9 might be involved in regulating the biological characteristics and the function of BMSCs in diabetes. We demonstrated that the miR-139-5p expression was increased in BMSCs derived from STZ-induced diabetic rats. MiR-139-5p mimics were able to inhibit cell proliferation, and migration and promoted senescence and apoptosis in vitro. MiR-139-5p induced the down-regulated expression of HOXA9 and c-Fos in BMSCs derived from normal rats. Moreover, miR-139-5p inhibitors reversed the tendency in diabetic-derived BMSCs. Further, gain-and-loss function experiments indicated that miR-139-5p regulated the functions of BMSCs by targeting HOXA9 and c-Fos. In vivo wound model experiments showed that the downregulation of miR-139-5p further promoted the epithelialization and angiogenesis of diabetic BMSC-mediated skin. In conclusion, induction of miR-139-5p upregulation mediated the impairment of BMSCs through the HOXA9/c-Fos pathway in diabetic rats. Therefore, miR-139-5p/HOXA9 might be an important therapeutic target in treating diabetic BMSCs and diabetic complications in the future.


Asunto(s)
Diabetes Mellitus Experimental , Células Madre Mesenquimatosas , MicroARNs , Ratas , Animales , Células Madre Mesenquimatosas/metabolismo , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Proliferación Celular/genética , Regulación hacia Abajo
2.
Int Wound J ; 16(6): 1304-1313, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31448507

RESUMEN

Providing a better understanding of the risk factors for amputation in this particular region, Hunan province, in China might help patients with diabetic foot ulcers receive timely and appropriate medical care and help prevent amputation. Diabetic foot ulcer patients referred to the Third Xiangya Hospital during the period between December 2014 and September 2018 were enrolled. Participants who underwent amputations and received conservative treatments were compared using univariate and multivariate analyses to identify the independent predictors of amputation. Those who required amputation presented significantly higher levels of white blood cell counts, platelet counts, erythrocyte sedimentation rate, C-reactive protein, and glycated haemoglobin (HbA1c) levels. However, levels of haemoglobin, postprandial plasma C-peptide, triglyceride, high-density lipoprotein cholesterol, albumin, and uric acid were decreased in patients with amputations. Patients with more advanced Wagner grades had much higher rates of amputation. Multivariable-adjusted odds ratios in stepwise logistic regression model was 1.317 for HbA1c (95% CI: 1.015-1.709), 0.255 for triglyceride (95% CI: 0.067-0.975), and 20.947 for Wagner grades (95% CI: 4.216-104.080). Independent risk factors for amputation in these Chinese diabetic foot ulcer patients included an elevated HbA1c level, lower triglyceride level, and higher Wagner grades.


Asunto(s)
Amputación Quirúrgica , Pie Diabético/cirugía , Extremidad Inferior/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Sedimentación Sanguínea , Proteína C-Reactiva/análisis , China/epidemiología , Femenino , Hemoglobina Glucada/análisis , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Recuento de Plaquetas , Estudios Retrospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Centros de Atención Terciaria , Triglicéridos/sangre , Adulto Joven
3.
J Pediatr Adolesc Gynecol ; 32(4): 363-367, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30974212

RESUMEN

STUDY OBJECTIVE: To compare clinician perspectives for the treatment of pelvic inflammatory disease (PID) with those of adolescent patients and parents. DESIGN: Cross-sectional study. SETTING: Urban academic pediatric and adolescent medicine practices and school-based health clinics in a large urban community with a high prevalence of sexually transmitted infections and a national sample of adolescent-serving clinicians. PARTICIPANTS: Female patients aged 12-19 years, parents raising an adolescent older than the age of 12 years in the urban community, and clinicians who serve adolescents recruited from regional and national listservs. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Visual analogue scale scores on a scale of 0-10 corresponding to preferences on patient disposition in 17 clinical scenarios for a hypothetical patient with PID. RESULTS: Compared with adolescents, clinicians were significantly more likely to endorse hospitalizations when patients presented with severe or complicated illness (ß = 0.9; standard error [SE], 0.22; P < .001), possible surgical emergency (ß = 0.83; SE, 0.2; P < .001), concurrent pregnancy (ß = 0.59; SE, 0.3; P = .046), or failure of outpatient treatment (ß = 0.58; SE, 0.29; P = .045). Compared with clinicians, adolescents were significantly more likely to endorse hospitalizations when patients presented at a young age (ß = 1.36; SE, 0.38; P < .001), were homeless (ß = 0.88; SE, 0.32; P = .007), were afraid to inform a partner (ß = 1.66; SE, 0.40; P < .001), or had unaware parents (ß = 2.86; SE, 0.39; P < .001). CONCLUSION: Clinicians were more likely to recommend hospitalization when doing so adhered to national guidelines on PID treatment. Adolescents opted for hospitalization more often than clinicians in scenarios in which patients exhibited social vulnerability. Clinicians should engage with adolescents in shared disposition planning and use a more nuanced approach to PID management for adolescents who might not be able to tolerate an outpatient regimen.


Asunto(s)
Prioridad del Paciente , Enfermedad Inflamatoria Pélvica/terapia , Pautas de la Práctica en Medicina , Adolescente , Adulto , Niño , Estudios Transversales , Femenino , Hospitalización , Humanos , Masculino , Padres/psicología , Embarazo
4.
Lab Chip ; 16(3): 506-14, 2016 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-26687070

RESUMEN

We report on a novel and cost-effective microfluidic platform that integrates immunomagnetic separation and cell enumeration via DNA-induced bead aggregation. Using a two-stage immunocapture microdevice, 10 µL of whole blood was processed to isolate CD4+ T-cells. The first stage involved the immuno-subtraction of monocytes by anti-CD14 magnetic beads, followed by CD4+ T-cell capture with anti-CD4 magnetic beads. The super hydrophilic surface generated during polydimethylsiloxane (PDMS) plasma treatment allowed for accurate metering of the CD4+ T-cell lysate, which then interacted with silica-coated magnetic beads under chaotropic conditions to form aggregates. Images of the resulting aggregates were captured and processed to reveal the mass of DNA, which was used to back-calculate the CD4+ T-cell number. Studies with clinical samples revealed that the analysis of blood within 24 hours of phlebotomy yielded the best results. Under these conditions, an accurate cell count was achieved (R(2) = 0.98) when compared to cell enumeration via flow cytometry, and over a functional dynamic range from 106-2337 cells per µL.


Asunto(s)
Antirretrovirales/administración & dosificación , Infecciones por VIH , Técnicas Analíticas Microfluídicas , Monitoreo Fisiológico , Recuento de Linfocito CD4/instrumentación , Recuento de Linfocito CD4/métodos , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Humanos , Masculino , Técnicas Analíticas Microfluídicas/instrumentación , Técnicas Analíticas Microfluídicas/métodos , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos
6.
Sex Transm Dis ; 40(6): 496-8, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23680907

RESUMEN

National survey data designed to delineate clinician perspectives on the indications to hospitalize adolescents for pelvic inflammatory disease indicate that clinicians endorse care consistent with the Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines but that there is less agreement on the social factors that may impair an adolescent's ability to self-care in the outpatient setting.


Asunto(s)
Actitud del Personal de Salud , Enfermedad Inflamatoria Pélvica/terapia , Guías de Práctica Clínica como Asunto/normas , Adolescente , Conducta del Adolescente , Centers for Disease Control and Prevention, U.S./normas , Femenino , Encuestas de Atención de la Salud , Hospitalización , Humanos , Autocuidado , Enfermedades de Transmisión Sexual/terapia , Estados Unidos
7.
Microbes Infect ; 15(5): 409-15, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23500187

RESUMEN

The mechanism of intrauterine hepatitis B virus infection has not been established. In this study, venous blood, cord blood, and placental tissues from 171 chronic hepatitis B virus infected pregnant women were tested for hepatitis B surface antigen, hepatitis B core antigen, and hepatitis B virus DNA. We found that residence, mode of delivery, age, and number of gestational weeks of pregnant women were not correlated with intrauterine hepatitis B virus infection, while neonates of mothers who were hepatitis B s antigen positive and hepatitis B e antigen positive (P < 0.01) or who had high hepatitis B virus DNA levels (≥10(6) copies/ml) were more likely to get an intrauterine infection (P < 0.01). The hepatitis B virus infection rate in placental cell layers gradiently decreased from the mother's side to the fetus's side of the placenta, but the odds ratio value of correlation between placental hepatitis B virus infection and intrauterine infection gradiently increased. The way of intrauterine hepatitis B virus infection may be through a layer-layer transmission pathway, although the possibility of placental leakage cannot be excluded.


Asunto(s)
Virus de la Hepatitis B/aislamiento & purificación , Hepatitis B/transmisión , Hepatitis B/virología , Transmisión Vertical de Enfermedad Infecciosa , Placenta/virología , Complicaciones Infecciosas del Embarazo/virología , Viremia , Adulto , ADN Viral/sangre , Femenino , Antígenos del Núcleo de la Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/sangre , Humanos , Recién Nacido , Embarazo , Adulto Joven
8.
Artículo en Inglés | MEDLINE | ID: mdl-31131365

RESUMEN

OBJECTIVE: The objective of this study is to estimate consumers' maximum willingness-to-pay (WTP) for follow-up PID services by physicians and community health nurses (CHNs), differences by consumer type (adolescents versus parents), and the differences in health-provider predicted WTP consumer estimates and actual consumer WTP estimates. METHODS: In this IRB-approved study, a contingent valuation method was used to collect WTP data regarding co-payments to physicians or nurses for clinical service delivery from the consumers of adolescent PID services (parents and adolescents) and health providers using a national convenience sample. Consumers were recruited from an academic pediatric and adolescent medicine clinic and five health department school-based health clinics in a large urban community with high (sexually transmitted infection) STI prevalence. Participants completed a web-based survey. Data were analyzed using linear regression analyses. RESULTS: Adolescents were willing to pay $36 more (95 % Cl : $27.9-44.3) for community health nursing care and parents were willing to pay $48 more dollars (95 % Cl : $40.3-$57.4) than physician's predicted. There were no significant differences in adolescent and parents WTP for physician or nursing services Consumers (adolescents & parents) WTP for physician PID services were on average $18.50 higher than CHN PID services (p = 0.01). Using physician estimates for WTP as the reference group, adolescents were willing to pay $56 more (95 % Cl : $48.6-$63.4) for physician care and parents were willing to pay $66 more (95 % Cl : $59.0-$72.8) than physician's predicted. CONCLUSION: Adolescents and parents are willing to pay more for physician follow-up for PID, but they are open to CHN follow-up visits based on the mean WTP for CHN visits. Since WTP also reflects the value that individuals place on a service, our data demonstrate that providers consistently underestimate the value consumers place on clinical services for x adolescents with PID.

9.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 6): o1916, 2012 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-22719670

RESUMEN

The crystal structure of the title compound, C(31)H(22)N(4)O(4), features weak C-H⋯O inter-actions. The dihedral angle between the fused benzene and furan rings is 2.49 (15)°, while that between the triazole and pyridine rings is 10.23(18)°.

10.
Sex Transm Infect ; 87(7): 583-7, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22001169

RESUMEN

PURPOSE: There is limited information about how the consumers of adolescent pelvic inflammatory disease (PID) care value health states associated with the disorder. The aim of this study is to determine and compare adolescent and parent PID-related health utilities. METHODS: Adolescent girls (N=134) and parents (N=121) completed a web-based utility elicitation survey. Participants reviewed five scenarios describing the health states associated with PID (outpatient treatment (mild-moderate disease), inpatient treatment (severe disease), ectopic pregnancy, infertility and chronic abdominal pain). After each scenario, participants were asked to rate health-related quality of life (HRQL) using a Visual Analogue Scale (VAS) and to complete a time trade-off (TTO) assessment. Data were evaluated using multiple linear (VAS) and quantile (TTO) regression analyses. RESULTS: Adolescents had significantly lower mean valuations (p<0.01) than the parents on the VAS for HRQL in each health state (outpatient (62 vs 76), inpatient (57 vs 74), ectopic (55 vs 73), infertility (59 vs 68) and chronic abdominal pain (48 vs 61)). Using quantile regression analysis, adolescents were also willing to give up more time for health gains indicated by lower median TTO scores (p<0.01) for outpatient treatment (0.98 vs 1.0), inpatient treatment (0.96 vs 1.0) and ectopic pregnancy (0.98 vs 1.0). CONCLUSIONS: The authors demonstrate that adolescents assign more disutility (lower valuations) than parents for HRQL and three of five of the TTO assessments for PID-related health states. Future economic evaluations using patient-specific preferences to determine resource allocation for PID management in adolescents should include adolescent health outcomes and utilities.


Asunto(s)
Aceptación de la Atención de Salud/estadística & datos numéricos , Enfermedad Inflamatoria Pélvica/diagnóstico , Enfermedad Inflamatoria Pélvica/terapia , Calidad de Vida/psicología , Adolescente , Adulto , Factores de Edad , Niño , Femenino , Salud , Humanos , Internet , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Adulto Joven
11.
World J Pediatr ; 7(3): 232-9, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21633859

RESUMEN

BACKGROUND: Melamine-contaminated milk powder was the cause of the 2008 outbreak of urolithiasis in young children and infants in China, but the prognosis of these children remains unknown. We hypothesized that urolithiasis induced by melamine-contaminated milk powder may be associated with secondary renal injury. METHODS: A total of 8335 children (≤6 years old) with a history of consuming melamine-contaminated milk powder were screened. Urine analysis and urinary system ultrasonography were performed. For children with urolithiasis, the basic information and the results of examination were recorded, and effective therapy was given. They were followed up for 6 months after the original diagnosis, and urinary microprotein profiles were measured. RESULTS: Of the 8335 children, 105 (1.26%) were diagnosed with melamine-contaminated milk powder-associated urolithiasis. The size of the stone was correlated with the duration of exposure to melamine. Six months later, 69.8% (67) of the children with urolithiasis passed stones (follow-up rate: 91.4%). Of the 67 children, 28 passed stones within 2 months. The higher possibility of passing a stone was correlated with the smaller diameter of the stone (P<0.001). The detection rate of abnormal urinary microprotein excretion (microalbumin, immunoglobulin G, and N-acetyl-ß-D-glucosidase) was 52.4% in children with persistent stones and 38.2% in those who passed their stones. The detection rate was lower in children who passed stones within 2 months (31.8%) than in those who passed stones in 2 to 6 months (50.0%). The levels of microalbumin/creatinine and immunoglobulin G/creatinine were significantly higher in children with persistent stones than in those who passed their stones. CONCLUSIONS: Early passage of a stone may reduce the renal injury induced by melamine-contaminated milk powder-associated urolithiasis.


Asunto(s)
Triazinas/efectos adversos , Urolitiasis/inducido químicamente , Animales , Niño , Preescolar , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Contaminación de Alimentos , Humanos , Lactante , Recién Nacido , Masculino , Leche , Estudios Prospectivos
12.
ACS Appl Mater Interfaces ; 1(1): 90-6, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20355759

RESUMEN

Solution-processable polyelectrolyte complexes (PECs) between poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA) were synthesized in aqueous NaOH and obtained in their solid forms by protection and deprotection of carboxylic acid groups. Elemental analysis, conductance measurement, and FT-IR showed that the composition and ionic complexation degree (ICD) of the PECs can be controlled effectively by tuning the NaOH concentration in both parent polyelectrolyte solutions. Thermal gravity analysis showed that PECs revealed good thermal stability, and differential scanning calorimetry showed that the glass transition temperature (Tg) of PECs increased with increasing ICD and finally became undetectable when ICD was above 0.16. Viscosity properties of the PEC solutions were well correlated to the ICD of PECs, and it was found that solid PECs could be redissolved in dilute NaOH without breaking the ionic complexation between PDDA and PAA. Homogeneous PEC membranes (HPECMs) were made from their concentrated solutions, and their morphologies were examined by field emission scanning electron microscopy. These novel HPECMs were subjected to dehydration of organics for the first time, and a very promising performance was obtained. Furthermore, another two solution-processable PECs between weak anionic polyelectrolyte and cationic polyelectrolyte were also synthesized by the same method and showed a very high separation performance.

13.
J Bacteriol ; 186(3): 750-7, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14729701

RESUMEN

The modified nucleoside 2-thiocytidine (s(2)C) has so far been found in tRNA from organisms belonging to the phylogenetic domains Archaea and Bacteria. In the bacteria Escherichia coli and Salmonella enterica serovar Typhimurium, s(2)C is present in position 32 of only four tRNA species-, and. An in-frame deletion of an S. enterica gene (designated ttcA, for "two-thio-cytidine") was constructed, and such a mutant has no detectable s(2)C in its tRNA. The TtcA protein family is characterized by the existence of both a PP-loop and a Cys-X(1)-X(2)-Cys motif in the central region of the protein but can be divided into two distinct groups based on the presence and location of additional Cys-X(1)-X(2)-Cys motifs in terminal regions of the sequence. Mutant analysis showed that both cysteines in this central conserved Cys-X(1)-X(2)-Cys motif are required for the formation of s(2)C. The DeltattcA1 mutant grows at the same rate as the congenic wild-type strain, and no growth disadvantage caused by the lack of s(2)C was observed in a mixed-population experiment. Lack of s(2)C32 did not reduce the selection rate at the ribosomal aminoacyl-tRNA site (A-site) for at any of its cognate CGN codons, whereas A-site selection at AGG by was dependent on the presence of s(2)C32. The presence of s(2)C32 in peptidyl- or in peptidyl- interfered with decoding in the A-site. The presence of s(2)C32 in decreased the rate of translation of the CGA codon but not that of the CGU codon.


Asunto(s)
Proteínas Bacterianas/química , Citidina/metabolismo , ARN Bacteriano/metabolismo , ARN de Transferencia/metabolismo , Salmonella typhimurium/química , Compuestos de Sulfhidrilo/metabolismo , Secuencias de Aminoácidos , Arginina/metabolismo , Proteínas Bacterianas/fisiología , Codón , Secuencia Conservada , Oxidación-Reducción , Biosíntesis de Proteínas , Salmonella typhimurium/genética , Azufre/metabolismo
14.
J Bacteriol ; 186(3): 758-66, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14729702

RESUMEN

tRNA from Salmonella enterica serovar Typhimurium contains five thiolated nucleosides, 2-thiocytidine (s(2)C), 4-thiouridine (s(4)U), 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U), 5-carboxymethylaminomethyl-2-thiouridine (cmnm(5)s(2)U), and N-6-(4-hydroxyisopentenyl)-2-methylthioadenosine (ms(2)io(6)A). The levels of all of them are significantly reduced in cells with a mutated iscS gene, which encodes the cysteine desulfurase IscS, a member of the ISC machinery that is responsible for [Fe-S] cluster formation in proteins. A mutant (iscU52) was isolated that carried an amino acid substitution (S107T) in the IscU protein, which functions as a major scaffold in the formation of [Fe-S] clusters. In contrast to the iscS mutant, the iscU52 mutant showed reduced levels of only two of the thiolated nucleosides, ms(2)io(6)A (10-fold) and s(2)C (more than 2-fold). Deletions of the iscU, hscA, or fdx genes from the isc operon lead to a similar tRNA thiolation pattern to that seen for the iscU52 mutant. Unexpectedly, deletion of the iscA gene, coding for an alternative scaffold protein for the [Fe-S] clusters, showed a novel tRNA thiolation pattern, where the synthesis of only one thiolated nucleoside, ms(2)io(6)A, was decreased twofold. Based on our results, we suggest two principal distinct routes for thiolation of tRNA: (i) a direct sulfur transfer from IscS to the tRNA modifying enzymes ThiI and MnmA, which form s(4)U and the s(2)U moiety of (c)mnm(5)s(2)U, respectively; and (ii) an involvement of [Fe-S] proteins (an unidentified enzyme in the synthesis of s(2)C and MiaB in the synthesis of ms(2)io(6)A) in the transfer of sulfur to the tRNA.


Asunto(s)
Proteínas de Escherichia coli , Nucleósidos/metabolismo , ARN Bacteriano/metabolismo , ARN de Transferencia/metabolismo , Salmonella typhimurium/genética , Compuestos de Sulfhidrilo/metabolismo , Proteínas HSP70 de Choque Térmico/fisiología , Proteínas Hierro-Azufre/metabolismo , Mutación , Operón , Salmonella typhimurium/crecimiento & desarrollo , Tiouridina/metabolismo
15.
RNA ; 9(6): 760-8, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12756333

RESUMEN

Using mutants (tgt, mnmA(asuE, trmU), mnmE(trmE), miaA, miaB, miaE, truA(hisT), truB) of either Escherichia coli or Salmonella enterica serovar Typhimurium and the trm5 mutant of Saccharomyces cerevisiae, we have analyzed the influence by the modified nucleosides Q34, mnm(5)s(2)U34, ms(2)io(6)A37, Psi39, Psi55, m(1)G37, and yW37 on -1 frameshifts errors at various heptameric sequences, at which at least one codon is decoded by tRNAs having these modified nucleosides. The frequency of -1 frameshifting was the same in congenic strains only differing in the allelic state of the various tRNA modification genes. In fact, in one case (deficiency of mnm(5)s(2)U34), we observed a reduced ability of the undermodified tRNA to make a -1 frameshift error. These results are in sharp contrast to earlier observations that tRNA modification prevents +1 frameshifting suggesting that the mechanisms by which -1 and +1 frameshift errors occur are different. Possible mechanisms explaining these results are discussed.


Asunto(s)
Sistema de Lectura Ribosómico , ARN de Transferencia/química , ARN de Transferencia/metabolismo , Anticodón , Secuencia de Bases , Escherichia coli/genética , Modelos Genéticos , Mutación , Nucleósidos/química , Saccharomyces cerevisiae/genética , Salmonella typhimurium/genética
16.
FEMS Microbiol Lett ; 211(2): 219-23, 2002 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-12076816

RESUMEN

The Bacillus subtilis global regulator AbrB was found to negatively control expression of sigW and genes of the sigma(W) regulon. AbrB bound to DNA regions in the autoregulatory sigW promoter and to some, but not all, of the other sigma(W)-dependent promoters in B. subtilis. Defects in antibiotic resistance properties caused by spo0A mutations are at least partially correlated with AbrB repression of the sigma(W) regulon.


Asunto(s)
Bacillus subtilis/genética , Proteínas Bacterianas , Proteínas de Unión al ADN/fisiología , Regulación Bacteriana de la Expresión Génica , Regulón , Factor sigma/genética , Factores de Transcripción/fisiología , Bacillus subtilis/metabolismo , Secuencia de Bases , Proteínas de Unión al ADN/genética , Regulación hacia Abajo , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Factor sigma/fisiología , Factores de Transcripción/genética
17.
J Mol Biol ; 317(4): 481-92, 2002 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-11955004

RESUMEN

Out of more than 500 sequenced cytosolic tRNAs, there is only one with an unmodified adenosine in the wobble position (position 34). The reason for this rare occurrence of A34 is that it is mostly deaminated to inosine-34 (I34). I34 is a common constituent in the wobble position of tRNAs and has a decoding capacity different from that of A34. We have isolated a mutant (proL207) of Salmonella typhimurium, in which the wobble nucleoside G34 has been replaced by an unmodified A in tRNA(Pro)(GGG), which is the only tRNA that normally reads the CCC codon. Thus, this mutant apparently has no tRNA that is considered cognate for the codon CCC. Despite this, the mutant grows normally. As expected, Pro-tRNA selection at the CCC codon in the A-site in a mutant deleted for the proL gene, which encodes the tRNA(Pro)(GGG), was severely reduced. However, in comparison this rate of selection was only slightly reduced in the proL207 mutant with its A34 containing tRNA(Pro)(AGG) suggesting that this tRNA reads CCC. Moreover, measurements of the interference by a tRNA residing in the P-site on the apparent termination efficiency at the A-site indicated that indeed the A34 containing tRNA reads the CCC codon. We conclude that A34 in a cytosolic tRNA is not detrimental to the cell and that the mutant tRNA(Pro)(AGG) is able to read the CCC codon like its wild-type counterpart tRNA(Pro)(GGG). We suggest that the decoding of the CCC codon by a 5'-AGG-3' anticodon occurs by a wobble base-pair between a protonated A34 and a C in the mRNA.


Asunto(s)
Adenosina/genética , Codón/genética , Citidina/genética , Citosol/metabolismo , ARN de Transferencia de Prolina/genética , ARN de Transferencia de Prolina/metabolismo , Salmonella typhimurium/genética , Emparejamiento Base , Secuencia de Bases , Codón de Terminación/genética , Genes Bacterianos/genética , Código Genético , Mutación/genética , Biosíntesis de Proteínas , ARN de Transferencia de Prolina/química , Especificidad por Sustrato
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