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941.
942.
Characterization of Staphylococcus aureus Isolates from Buffalo, Bovine, Ovine, and Caprine Milk Samples Collected in Rio de Janeiro State, Brazil 下载免费PDF全文
Marta Aires-de-Sousa Carlos E. S. R. Parente Olney Vieira-da-Motta Isabel C. F. Bonna Denise A. Silva Hermínia de Lencastre 《Applied microbiology》2007,73(12):3845-3849
Eighty-four staphylococcal isolates were obtained from milk samples from cows, sheep, goats, and buffalo with subclinical mastitis and from colonization samples from ostriches. The animals were hosted in 18 small dairy herds and an ostrich breeding located in 10 municipalities of the state of Rio de Janeiro, Brazil. Thirty isolates were identified as Staphylococcus aureus by biochemical and molecular techniques and were comparatively characterized by phenotypic and genotypic methods. The molecular characterization by pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) revealed five clonal types (PFGE A, spa type t359, sequence type 747 [ST747]; PFGE B, spa type t1180, ST750; PFGE C, spa type t605, ST126; PFGE D, spa type t127, ST751; and PFGE F, spa type t002, ST5). None of the isolates harbored the Panton-Valentine leukocidin or exfoliative toxin D gene. The detection of major clone A (in 63% of the isolates) in different herds, among all animal species studied, and in infection and colonization samples evidenced its geographical spread among Rio de Janeiro State and no host preference among the animal species. Comparison with S. aureus from a human origin suggested that all but one clone found in the present study might be animal specific. 相似文献
943.
Measuring ELF fields produced by mobile phones and personal digital assistants (PDAs) 总被引:1,自引:0,他引:1
Silva M 《Bioelectromagnetics》2007,28(7):583-4; discussion 584-5
944.
We assessed potential non-response bias in obtaining information on residential extremely low-frequency power frequency magnetic field (MF) in Taiwan. All households occupied by children aged less than 7 years in two study districts, one in an urban town and the other in a rural town, were visited and solicited for on-site measurements in late 2003. The initial response rate was only 32% (33/104, urban) and 60% (61/101, rural). In the same season 1 year later, we performed a second survey of those who declined to be measured at the initial survey and successfully measured another 77 residences (50 and 27 for urban and rural districts, respectively). The two districts were selected mainly because the local public health officers were quite willing to assist the initial survey and to inform residents of the second survey. Except for meteorological conditions, the two surveys came up with very similar findings regarding residential characteristics and power facilities surrounding the houses. The mean residential MF for the urban residences was .121 and .140 micro-Tesla (microT) (P = .620) for the two surveys. The corresponding figures for the rural residences were .119 and .115 microT (P = .802). Although limited in its scope, this study tends to indicate that measurement studies of residential MF are less likely to suffer from serious selection bias if sampling is confined within a small district where people have similar socioeconomic characteristics. 相似文献
945.
Gasparin G Miyata M Coutinho LL Martinez ML Teodoro RL Furlong J Machado MA Silva MV Sonstegard TS Regitano LC 《Animal genetics》2007,38(5):453-459
Differences in domestication and selection processes have contributed to considerable phenotypic and genotypic differences between Bos taurus and Bos indicus cattle breeds. Of particular interest in tropical and subtropical production environments are those genetic differences between subspecies that underlie the phenotypic extremes in tolerance and susceptibility to parasite infection. In general, B. taurus cattle are more susceptible to ectoparasites than B. indicus cattle in tropical environments, and much of this difference is under genetic control. To identify genomic regions involved in tick resistance, we developed a B. taurus x B. indicus F(2) experimental population to map quantitative trait loci (QTL) for resistance to the Riphicephalus (Boophilus) microplus tick. About 300 individuals were measured for parasite load in two seasons (rainy and dry) and genotyped for 23 microsatellite markers covering chromosomes 5, 7 and 14. We mapped a suggestive chromosome-wide QTL for tick load in the rainy season (P < 0.05) on chromosome 5. For the dry season, suggestive (P < 0.10) chromosome-wide QTL were mapped on chromosomes 7 and 14. The additive effect of the QTL on chromosome 14 corresponds to 3.18% of the total observed phenotypic variance. Our QTL-mapping study has identified different genomic regions controlling tick resistance; these QTL were dependent upon the season in which the ticks were counted, suggesting that the QTL in question may depend on environmental factors. 相似文献
946.
Farah SM de Souza EM Pedrosa FO Irino K da Silva LR Rigo LU Steffens MB Pigatto CP Fadel-Picheth CM 《Letters in applied microbiology》2007,44(6):607-612
AIMS: To investigate the prevalence and characteristics of Shiga toxin-producing Escherichia coli (STEC) in cattle from Paraná State, southern Brazil. METHODS AND RESULTS: One hundred and seven faeces cattle samples were cultured on Sorbitol-MacConkey agar. Escherichia coli colonies were tested for production of Shiga toxin using Vero-cell assay. A high prevalence (57%) of STEC was found. Sixty-four STEC were serotyped and examined for the presence of stx(1), stx(2), eae, ehxA and saa genes and stx(2) variants. The isolates belonged to 31 different serotypes, of which three (O152:H8, O175:H21 and O176:H18) had not previously been associated with STEC. A high prevalence of stx(2)-type genes was found (62 strains, 97%). Variant forms found were stx(2), stx(2c), stx(2vhb), stx(2vO111v/OX393) and a form nonclassifiable by PCR-RFLP. The commonest genotypes were stx(2)ehxA saa and stx(1)stx(2)ehxA saa. CONCLUSIONS: A high frequency of STEC was observed. Several strains belong to serotypes previously associated with human disease and carry stx(2) and other virulence factors, thus potentially representing a risk to human health. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study of STEC in Paraná State, and its findings emphasize the need for proper cattle handling to prevent human contamination. 相似文献
947.
Thyroid Hormones Reorganize the Cytoskeleton of Glial Cells Through Gfap Phosphorylation and Rhoa-Dependent Mechanisms 总被引:1,自引:0,他引:1
Zamoner A Funchal C Jacques-Silva MC Gottfried C Barreto Silva FR Pessoa-Pureur R 《Cellular and molecular neurobiology》2007,27(7):845-865
Thyroid hormones (3,5,3′-triiodo-l-thyronine, T3; 3,5,3′,5′-l-tetraiodothyronine, T4; TH) play crucial roles in the growth and differentiation of the central nervous system. In this study, we investigated the
actions of TH on proliferation, viability, cell morphology, in vitro phosphorylation of glial fibrillary acidic protein (GFAP)
and actin reorganization in C6 glioma cells. We first observe that long-term exposure to TH stimulates cell proliferation
without induce cell death. We also demonstrate that after 3, 6, 12, 18, and 24 h treatment with TH, C6 cells and cortical
astrocytes show a process-bearing shape. Furthermore, immunocytochemistry with anti-actin and anti-GFAP antibodies reveals
that TH induces reorganization of actin and GFAP cytoskeleton. We also observe an increased in vitro 32P incorporation into GFAP recovered into the high-salt Triton insoluble cytoskeletal fraction after 3 and 24 h exposure to
5×10−8 and 10−6 M T3, and only after 24 h exposure to 10−9 M T4. These results show a T3 action on the phosphorylating system associated to GFAP and suggest a T3-independent effect of T4 on this cytoskeletal protein. In addition, C6 cells and astrocytes treated with lysophosphatidic acid, an upstream activator
of the RhoA GTPase pathway, totally prevented the morphological alterations induced by TH, indicating that this effect could
be mediated by the RhoA signaling pathway. Considering that IF network can be regulated by phosphorylation leading to reorganization
of IF filamentous structure and that alterations of the microfilament organization may have important implications in glial
functions, the effects of TH on glial cell cytoskeleton could be implicated in essential neural events such as brain development. 相似文献
948.
Diniz PH Silva JH Gomez MV Guatimosim C Gomez RS 《Cellular and molecular neurobiology》2007,27(6):757-770
Experimental data suggest that halothane anesthesia is associated with significant changes in dopamine (DA) concentration
in some brain regions but the mechanism of this effect is not well known. Rat brain cortical slices were labeled with [3H]DA to further characterize the effects of halothane on the release of this neurotransmitter from the central nervous system.
Halothane induced an increase on the release of [3H]DA that was dependent on incubation time and anesthetic concentration (0.012, 0.024, 0.048, 0.072 and 0.096 mM). This effect
was independent of extracellular or intracellular calcium. In addition, [3H]DA release evoked by halothane was not affected by TTX (blocker of voltage-dependent Na+ channels) or reserpine (a blocker of vesicular monoamine transporter). These data suggest that [3H]DA release induced by halothane is non-vesicular and would be mediated by the dopamine transporter (DAT) and norepinephrine
transporter (NET). GBR 12909 and nomifensine, inhibitors of DAT, decreased the release of [3H]DA evoked by halothane. Nisoxetine, a blocker of NET, reduced the release of [3H]DA induced by halothane. In addition, GBR 12909, nisoxetine and, halothane decrease the uptake of [3H]DA into rat brain cortical slices. A decrease on halothane-induced release of [3H]DA was also observed when the brain cortical slices were incubated at low temperature and low extracellular sodium, which
are known to interfere with the carrier-mediated release of the neurotransmitter. Ouabain, a Na+/K+ ATPase pump inhibitor, which induces DA release through reverse transport, decreased [3H]DA release induced by halothane. It is suggested that halothane increases [3H]DA release in brain cortical slices that is mediated by DAT and NET present in the plasma membrane. 相似文献
949.
Sumida M Kotaki M Islam MM Djong TH Igawa T Kondo Y Matsui M Anslem de S Khonsue W Nishioka M 《Zoological science》2007,24(6):547-562
The rice frog (Fejervarya limnocharis) species complex is widely distributed, from India to Japan, and most prevalently in Southeast Asia. Conspicuous morphological variation has been reported for this species complex throughout its distribution range. In the present study, we used mtDNA gene sequence and allozyme analyses to infer evolutionary affinities within this species complex using eight populations (Sri Lanka; Bangkok and Ranong in Thailand; Taiwan; and Hiroshima, Okinawa, Ishigaki and Iriomote in Japan). We also conducted crossing experiments among four populations from Japan, Thailand, and Sri Lanka in order to find out more about the reproductive isolating mechanisms that might exist among the East, Southeast, and South Asian populations of this species complex. The crossing experiments revealed that the Sri Lanka population is reproductively isolated from the Hiroshima, Bangkok, and Ranong populations by complete hybrid inviability, and that the Bangkok population may be reproductively isolated from the Hiroshima population by partial hybrid inviability. Thus, it is not unreasonable to regard the Sri Lanka population as a species separated from F. limnocharis. The mtDNA and allozyme data showed that the Ranong population is most closely related to the Bangkok population in nuclear genome, but more similar to the Okinawa and Taiwan populations in mtDNA genome. The present, preliminary survey may raise questions about the species status of these particular populations and also about the nature of the biological species concept. 相似文献
950.
L. C. S. Ferreira R. Bressan-Smith T. F. Elias F. F. Silva L. H. Viana J. G. Oliveira 《Photosynthetica》2007,45(1):23-29
Primary leaves of young plants of common bean (Phaseolus vulgaris cv. Carioca and Negro Huasteco) and cowpea (Vigna unguiculata Walp cv. Epace 10) were exposed to high irradiance (HI) of 2 000 μmol m−2 s−1 for 10, 20, and 30 min. The initial fluorescence (F0) was nearly constant in response to HI in each genotype except for Carioca. A distinct reduction of maximum fluorescence
(Fm) was clearly observed in stressed genotypes of beans after 20 min followed by a slight recovery for the longer stress times.
In common bean, the maximum quantum yield (Fv/Fm) was reduced slowly from 10 to 30 min of HI. In cowpea, only a slight reduction of Fv/Fm was observed at 20 min followed by recovery to normal values at 30 min. HI resulted in changes in the photochemical (qP) and non-photochemical (qN) quenching in both species, but to a different extent. In cowpea plants, more efficiency in the use of the absorbed energy
under photoinhibitory conditions was related to increase in qP and decrease in qN. In addition, lipid peroxidation changed significantly in common bean genotypes with an evident increase after 20 min of
HI. Hence the photosynthetic apparatus of cowpea was more tolerant to HI than that of common bean and the integrity of cowpea
cell membranes was apparently maintained under HI. 相似文献