RESUMEN
In this study, long-term effects of Ni, a widespread heavy metal in the aquatic ecosystems, have been determined on growth and lethality of the clam Ruditapes philippinarum, a known bioindicator of the marine environment. Three/four-month-old bivalves have been exposed to different concentrations of Ni dissolved in synthetic seawater. Growth and lethality as endpoints after 28 days of treatment have been observed. Obtained results are the following: EC25 = 3.97 ± 0.94 and 9.45 ± 1.59 mg/L and NOEC = 1.56 and 6.25 mg/L for growth and mortality, respectively. Moreover, this study can be considered a new tool for the evaluation of fitness of bivalve clam, together with other biological responses following to the biological impacts of metal pollution.
Asunto(s)
Bivalvos/efectos de los fármacos , Níquel/toxicidad , Animales , Bivalvos/crecimiento & desarrollo , Monitoreo del Ambiente , Contaminantes Ambientales/administración & dosificación , Contaminantes Ambientales/toxicidad , Níquel/administración & dosificaciónRESUMEN
OBJECTIVE: To characterize true coagulase-negative Staphylococcus (CoNS) infections in infants receiving neonatal intensive care. STUDY DESIGN: Retrospective cohort study of neonatal intensive care unit (NICU) infants with clinical sepsis and CoNS isolated from ≥ 2 blood cultures (BCs) or one BC and a sterile site (proved infection) or CoNS isolated from one BC and deemed significant after blinded data review (probable infection). RESULT: In all, 98% of 40 proved and 96% of 55 probable infections occurred in infants with birth weight (BW) <2000 g and gestation <34 weeks. Total central lines (CLs) placed, but not CL duration or presence in situ, predicted proved (odds ratio (OR) 3.5, 95% confidence interval (CI) 1.4 to 8.3; P=0.005) and probable infection (OR 2.7, 95% CI 1.3 to 5.6; P=0.007) by multivariate analysis as did lethargy and gastric residuals. CONCLUSION: True CoNS infection is unlikely in infants with BW >2000 g and gestation >34 weeks. Total CL required for care, lethargy and gastric residuals predicted true CoNS infection.
Asunto(s)
Bacteriemia/diagnóstico , Bacteriemia/microbiología , Cateterismo Venoso Central , Coagulasa/metabolismo , Infección Hospitalaria/diagnóstico , Infección Hospitalaria/microbiología , Medios de Cultivo , Contaminación de Equipos , Recien Nacido con Peso al Nacer Extremadamente Bajo , Recién Nacido de Bajo Peso , Unidades de Cuidado Intensivo Neonatal , Infecciones Estafilocócicas/diagnóstico , Infecciones Estafilocócicas/microbiología , Staphylococcus/enzimología , Bacteriemia/epidemiología , Infección Hospitalaria/epidemiología , Estudios Transversales , Diagnóstico Diferencial , Femenino , Humanos , Recién Nacido , Masculino , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Infecciones Estafilocócicas/epidemiologíaRESUMEN
The posttranslational translocation of proteins across the endoplasmic reticulum (ER) membrane in yeast requires ATP hydrolysis and the action of hsc70s (DnaK homologues) and DnaJ homologues in both the cytosol and ER lumen. Although the cytosolic hsc70 (Ssa1p) and the ER lumenal hsc70 (BiP) are homologous, they cannot substitute for one another, possibly because they interact with specific DnaJ homologues on each side of the ER membrane. To investigate this possibility, we purified Ssa1p, BiP, Ydj1p (a cytosolic DnaJ homologue), and a GST-63Jp fusion protein containing the lumenal DnaJ region of Sec63p. We observed that BiP, but not Ssa1p, is able to associate with GST-63Jp and that Ydj1p stimulates the ATPase activity of Ssa1p up to 10-fold but increases the ATPase activity of BiP by <2-fold. In addition, Ydj1p and ATP trigger the release of an unfolded polypeptide from Ssa1p but not from BiP. To understand further how BiP drives protein translocation, we purified four dominant lethal mutants of BiP. We discovered that each mutant is defective for ATP hydrolysis, fails to undergo an ATP-dependent conformational change, and cannot interact with GST-63Jp. Measurements of protein translocation into reconstituted proteoliposomes indicate that the mutants inhibit translocation even in the presence of wild-type BiP. We conclude that a conformation- and ATP-dependent interaction of BiP with the J domain of Sec63p is essential for protein translocation and that the specificity of hsc70 action is dictated by their DnaJ partners.
Asunto(s)
Adenosina Trifosfato/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Proteínas de Transporte de Membrana , Chaperonas Moleculares/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatasas , Secuencia de Bases , Transporte Biológico Activo , Cartilla de ADN/genética , Retículo Endoplásmico/metabolismo , Proteínas Fúngicas/genética , Proteínas del Choque Térmico HSP40 , Proteínas HSP70 de Choque Térmico/química , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Membranas Intracelulares/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Modelos Moleculares , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Mutación , Conformación Proteica , Procesamiento Proteico-Postraduccional , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genéticaRESUMEN
Twelve thousand two hundred and eighty nine Pap smears were collected from public hospitals and from private practices during a four year period (January 1987 to December 1990). 4.2% of Pap smears exhibited condylomatous or dysplastic lesions. 94.5% of such lesions were encountered in Pap smears taken from the transformation zone and which contained endocervical cells. Therefore, these smears represent the only adequate sample for cervical cancer screening. In our study, a close concertation between biologists and clinicians results in an improvement of the smear quality. The percentage of those containing endocervical cells increased from 49% in 1987 to 72% in 1990. Then, more cervical lesions were encountered on smears of patients from a low socio-economic level. New techniques such as detection of human papillomavirus (HPV) DNA on routine Pap smears by in situ hybridization would allow to improve the cytological diagnosis of HPV infections, mainly for non specific cytological alterations (11% in our series for 1990) and for cytological aspects of dysplasia only. These results point out how a cervical cancer screening can be better carried out.