Autoantigenic nuclear proteins of a clinically atypical renal vasculitis     

Julio Avila  Elisa Acosta  María-del-Valle Machargo  María-Francisca Arteaga  Eduardo Gallego  Haridian Cañete  José-Javier García-Pérez  Pablo Martín-Vasallo 《Journal of Autoimmune Diseases》2008,5(1):3

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Detection of streptomycin resistance in Erwinia amylovora strains isolated from apple orchards in Chihuahua, Mexico     

Adrian Ponce de León Door  Alejandro Romo Chacón  Carlos Acosta Muñiz. 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(2):223-229

Fire blight, one of the most severe diseases of apple and pear, is caused by the bacterium Erwinia amylovora. One control method is the use of antibiotics like streptomycin; however, streptomycin is the only antibiotic registered to control fire blight. A total of 107 E. amylovora strains were isolated from apple orchards located in Cuauhtémoc and Guerrero, Chihuahua, two major apple-producing areas in Mexico, showing 40 and 24 % streptomycin-resistant strains, respectively. The identification of E. amylovora strains was performed by polymerase chain reaction (PCR) amplification of a 900-bp region located within the non-transferable pEA29 plasmid and by amplification of a specific 1,269-bp region located on the E. amylovora chromosome. The 107 isolates tested carried the pEA29 plasmid, and 36 % of the isolates from both locations showed high resistance to streptomycin at levels that ranged from 200 to ≥1,000 μg ml^?1 streptomycin. The strA-strB and aadA genes, which encode enzymes that inactivate streptomycin, and a mutation in codon 43 of the rpsL gene that confers high resistance to the antibiotic were examined to determine the mechanism of streptomycin resistance. In total, 95 % of the resistant strains showed a single base pair mutation in codon 43 of the rpsL gene, causing an amino acid substitution in ribosomal protein S12. The presence of strA-strB and aadA genes or the rpsL mutation was not identified in the other 5 % of resistant strains, suggesting the existence of a new streptomycin resistance mechanism in E. amylovora.  相似文献   

Health risk behaviors and work injury among hispanic adolescents and farmworkers     

Vela Acosta MS  Sanderson M  Cooper SP  Pérez A  Roberts RE 《Journal of agricultural safety and health》2007,13(2):117-136

Adolescents may engage in health risk behaviors that increase their likelihood of injury. Employment places adolescents at risk of work-related injuries. This study responds to the paucity of data on the relationship between adolescent health risk behaviors and work-related injury. This cross-sectional study included the administration of anonymous surveys to ninth graders (n=4914) who attended high schools in south Texas. An aggregate risk score (ARS) was developed based on health risk behaviors. The ARS was analyzed as an outcome using linear regression. Associations between health risk behaviors and work-related injury were assessed with logistic regression. Of the respondents, 19% reported they had a job, and 14% reported that they had been employed in farmwork. Farmwork-related injury was reported by 9% of adolescents, and 12% reported other work-related injury. Mean ARS scores were significantly higher (p < 0.05) for both male and female adolescents who reported a work-related injury compared to nonworking adolescents, and for males who had done migrant farmwork compared to all other adolescent males. The ARS increased as hours worked per week increased. After controlling for confounding factors, a statistically significant association was found between ARS and non-farmwork, work-related injury, but not between ARS and farmwork-related injury. Farmworkers with high ARS were more likely to report non-farmwork, work-related injuries. The predictors of work-related injury in the adolescent groups, particularly for farmworkers and migrants who are under additional stress, remain an important occupational health area to be addressed.  相似文献   

Enzyme activities in semiarid soils under conservation reserve program,native rangeland,and cropland     

Veronica Acosta‐Martínez  Susanne Klose  Ted M. Zobeck 《植物养料与土壤学杂志》2003,166(6):699-707

There is limited knowledge of biochemical processes in low carbon content soils of semiarid regions under different land use and management. This study investigated several enzyme activities of C, N, P, and S transformations in semiarid soils with different clay (10–21 %) and sand (59–85 %) contents that were under conservation reserve program (CRP), native rangeland (NR), and cropland (CL) under sunflowers (Eriophyllum ambiguum (Gray)), continuous cotton (Gossypium hirsutum L.), or in rotations with wheat (Triticum aestivum L.) or sorghum (Sorghum bicolor L.) in West Texas, USA. Soils under CRP and NR showed higher total C and N contents than cultivated soils under continuous cotton, but soil pH (6.7–8.4) was not affected by the management or land use studied. The activities of β‐glucosidase, β‐glucosaminidase, arylamidase, acid and alkaline phosphatase, phosphodiesterase, and arylsulfatase (mg product (kg soil)^–1 h^–1) were lower in CL under continuous cotton compared to cotton in rotation with other crops, CRP, and NR. The enzyme activities were also lower when compared to soils from other regions. Linear regression analyses indicated positive correlations between enzyme activities and total C (r values up to 0.96, P < 0.01). There was a positive relationship between enzyme activities and total N, but soil pH showed the opposite trend. Enzyme activities were significantly intercorrelated with r values up to 0.98 (P < 0.001). The specific enzyme activities (mg product (g organic C)^–1) were lower in continuous cotton in comparison to the uncultivated soils (i.e., NR and CRP) reflecting differences in organic matter quantity and quality due to cultivation. Among the enzymes studied, the specific activities of β‐glucosidase and arylamidase showed a more pronounced decrease with increasing soil depth. In general, soils under CRP or wheat‐cotton rotations revealed higher enzyme activities than soils under the common agricultural practice for these regions, i.e., continuous cotton under conventional tillage.  相似文献   

Cotton Genetic Resources in the Western States of Mexico: In situ Conservation Status and Germplasm Collection for ex situ Preservation     

Mauricio Ulloa  James McD. Stewart  Enrique A. Garcia-C.  Salvador Godoy-A.  Arturo Gaytan-M.  N. Sebastián Acosta 《Genetic Resources and Crop Evolution》2006,53(4):653-668

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Lithospheric Contributions to Arc Magmatism: Isotope Variations Along Strike in Volcanoes of Honshu, Japan     

AB Kersting  RJ Arculus  DA Gust 《Science (New York, N.Y.)》1996,272(5267):1464-1468

Major chemical exchange between the crust and mantle occurs in subduction zone environments, profoundly affecting the chemical evolution of Earth. The relative contributions of the subducting slab, mantle wedge, and arc lithosphere to the generation of island arc magmas, and ultimately new continental crust, are controversial. Isotopic data for lavas from a transect of volcanoes in a single arc segment of northern Honshu, Japan, have distinct variations coincident with changes in crustal lithology. These data imply that the relatively thin crustal lithosphere is an active geochemical filter for all traversing magmas and is responsible for significant modification of primary mantle melts.  相似文献   

Size Dependence of Structural Metastability in Semiconductor Nanocrystals     

CC Chen  AB Herhold  CS Johnson  AP Alivisatos 《Science (New York, N.Y.)》1997,276(5311):398-401

The kinetics of a first-order, solid-solid phase transition were investigated in the prototypical nanocrystal system CdSe as a function of crystallite size. In contrast to extended solids, nanocrystals convert from one structure to another by single nucleation events, and the transformations obey simple unimolecular kinetics. Barrier heights were observed to increase with increasing nanocrystal size, although they also depend on the nature of the nanocrystal surface. These results are analogous to magnetic phase transitions in nanocrystals and suggest general rules that may be of use in the discovery of new metastable phases.  相似文献   

Virulence factors and pathogenicity of Hafnia alvei for gilthead seabream, Sparus aurata L     

Padilla D  Real F  Gómez V  Sierra E  Acosta B  Déniz S  Acosta F 《Journal of fish diseases》2005,28(7):411-417

Virulence factors (eae gene, haemolytic capacity, fimbriae, resistance to the bactericidal effect of serum, siderophore production) and pathogenicity for gilthead seabream, Sparus aurata L., were analysed for 23 Hafnia alvei strains. None of the strains used in LD50 studies were lethal for seabream at doses as high as >10(8) cfu mL(-1). In chronic challenge studies differences in severity of the inflammatory response were observed between strains. On the basis of correlation of the inflammatory response to different strains of H. alvei in seabream with those virulence factors studied, it was only possible to establish a positive correlation between pathogenicity and resistance to the bactericidal effect of fish serum. Gilthead seabream is thus a species with considerable resistance to experimental infection with H. alvei. The bacterium does, however, have the capacity to remain viable in seabream for up to 3 months, without any clinical signs. Hafnia alvei is a well-recognized human and animal pathogen. Thus, as the pathogen can coexist with aquaculture operations, cultured gilthead seabream could represent a risk to human health as a carrier in some circumstances.  相似文献   

Synergistic Effect of Porcine Follicular Fluid and Dibutyryl Cyclic Adenosine Monophosphate on Development of Parthenogenetically Activated Oocytes from Pre‐Pubertal Gilts     

AB Nascimento  MS Albornoz  L Che  JA Visintin  V Bordignon 《Reproduction in domestic animals》2010,45(5):851-859

This study investigated the effect of porcine follicular fluid (PFF) and dibutyryl cyclic adenosine monophosphate (dbcAMP) during in vitro maturation (IVM) of porcine oocytes on meiotic maturation, fertilization and embryo development, and compared the effect of supplementing the embryo culture media with PFF or foetal bovine serum (FBS) on embryo development. Oocytes from pre‐pubertal gilts were IVM for 44 h, and parthenogenetically activated or in vitro‐fertilized. Embryos were cultured in porcine zygote medium (PZM3) for 7 days. Cleavage and blastocyst rates were evaluated at 48 h and 7 days of culture. The supplementation of the IVM medium with 25% PFF and 1 mm dbcAMP for the first 22 h resulted in more (p < 0.05) embryos developing to the blastocyst stage as compared with the inclusion of dbcAMP alone. The dbcAMP + PFF combination increased (p < 0.05) the average number of nuclei per blastocyst as compared with either of these components alone or in its absence. A synergistic effect of dbcAMP + PFF during IVM was also reflected in the capacity of oocytes to regulate sperm penetration and prevent polyspermy, as twice as many oocytes from the control group were penetrated by more than one sperm as compared with those matured in the presence of both dbcAMP and PFF. The supplementation of PZM3 with 10% FBS from days 5 to 7 of culture significantly improved the total cell quantity in embryos derived either from control or dbcAMP + PFF matured oocytes. There was no effect on the total cell quantity when FBS was replaced by the same concentration of PFF. These studies showed that dbcAMP, PFF and FBS can improve both the quantity (57.3% vs 41.5%) and quality (74.8 vs 33.3 nuclei) of porcine blastocysts derived from oocytes recovered of pre‐pubertal gilts.  相似文献   

Fullerene and omega-3 and omega-6 fatty acids on fish brain antioxidant status     

da Silva Acosta D  Kneip FC  Alves de Almeida E  Ventura-Lima J  Monserrat JM  Geracitano LA 《Fish physiology and biochemistry》2012,38(5):1477-1485

The carbon nanomaterial fullerene (C(60)) can act as anti or pro-oxidant. The aim of this study was to evaluate, in cell suspensions of carp brains (Cyprinus carpio, Cyprinidae), the effect of C(60) after a pre-treatment with polyunsaturated fatty acid (PUFAs) such as omega-3 (docosahexaenoic acid, DHA) and omega-6 (linoleic acid, LA). Assays consisted of a pre-treatment with PUFA (48?h) and then exposure to C(60) (2?h). Cell viability and total anti-oxidant capacity did not differ (p?>?0.05). A reduction (p?相似文献