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Capita R Alonso-Calleja C Mereghetti L Moreno B del Camino García-Fernández M 《Journal of applied microbiology》2002,92(1):90-96
AIMS: The validity of the international phage set and 13 experimental phages for subtyping Listeria monocytogenes strains isolated from poultry in Spain was investigated. METHODS AND RESULTS: Ninety-six L. monocytogenes strains (52 from serogroup 1/2 and 44 from serogroup 4) were phage-typed using the international phage set, 10 experimental phages for typing serogroup 1/2 strains (seven isolated in France: 1313, 9425, 1807, 351, 881, 717 and 586-, and three from Denmark: 5775, 12682 and 6223-) and three experimental phages isolated in France for typing serogroup 4 strains (2425 A, 4286 and 197). Percentages of serogroup 1/2, serogroup 4 and total phage-typeable strains were 57.7%, 52.3% and 55.2%, respectively. Important differences in the behaviour of the phages tested were found. The typeability rate, the specificity index and the percentage of strong reactions were greater in the phages of international set than in the experimental phages. The number of phage typeable strains and the number of phage types (42) were not modified by the use of experimental phages. CONCLUSIONS: The phage set used was not effective for typing L. monocytogenes strains from poultry in Spain, because a low typeability rate was found. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results suggest the importance of the availability of new phages specific to a geographical area in order to improve the typeability of the system. 相似文献
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Ramos HJ Roncato-Maccari LD Souza EM Soares-Ramos JR Hungria M Pedrosa FO 《Journal of biotechnology》2002,97(3):243-252
To monitor the colonization of wheat roots by Azospirillum brasilense, we constructed several plasmids based on the pBBR1 replicon expressing the gfp and gusA genes constitutively. Both genes were placed under control of the gentamycin resistance gene promoter resulting in high levels of expression in Escherichia coli and A. brasilense. The constructed plasmids were stably maintained in A. brasilense strains even in the absence of selective pressure. The colonization of wheat plants grown under controlled conditions in sterilized vermiculite by A. brasilense strain FP2 (a Sp7-derivative) transconjugants containing these plasmids was monitored. Bacteria expressing GFP were easily observed in fresh plant material by fluorescence microscopy. Cell aggregates and single bacteria were visualized on the surfaces of young root zones, such as roots hairs and lateral roots. Large cellular clumps were observed at the points of lateral root emergence or at intercellular spaces of root epidermal cells 30 days after inoculation. Although we failed to detected bacteria in internal cortical and xylem tissues of wheat roots, the initial stage of endophytic colonization by A. brasilense may involve the sites detected in this work. 相似文献
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Peripheral benzodiazepine receptor ligand-melphalan conjugates for potential selective drug delivery to brain tumors 总被引:3,自引:0,他引:3
Trapani G Laquintana V Latrofa A Ma J Reed K Serra M Biggio G Liso G Gallo JM 《Bioconjugate chemistry》2003,14(4):830-839
To gain insight into the strategy to target PBR ligand-drug conjugates to brain tumors, novel N-imidazopyridinacetyl-melphalan conjugates and the corresponding ethyl esters have been prepared and evaluated for their cytotoxicity in melphalan-sensitive human (SF126, SF188) and rat (RG-2) glioma cell lines. These conjugates exhibited PBR binding affinity with IC(50) values ranging from 57 and 2614 nM. By a computational approach it can be predicted that these conjugates possess significant brain penetration. The stability of the conjugates in 0.05 M phosphate buffer at pH 7.4 and, in some cases, in dilute human serum solution was determined. All the ethyl ester derivatives were stable in 0.05 M phosphate buffer at pH 7.4 and their half-lives exceeded 28 h. Conversely, under the same conditions, the corresponding acids were found to undergo a fast cleavage within a few minutes. HPLC-MS analysis of the mixture from degradation in buffer and physiological medium of the representative cases allowed the identification of their main degradation products. A plausible degradation pathway accounting for the available experimental data is presented. 相似文献
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Platinum toxicity and gene expression in Xenopus embryos: analysis by FETAX and differential display
Monetti C Bernardini G Vigetti D Prati M Fortaner S Sabbioni E Gornati R 《Alternatives to laboratory animals : ATLA》2003,31(4):401-408
Since the level of platinum in the environment is destined to increase, because of its use in vehicle catalytic converters, the toxicity of platinum needs further investigation. In this study, the frog embryo teratogenesis assay-Xenopus (FETAX) was used to compare the embryotoxicity and teratogenicity of two common platinum species, (NH4)2PtCl4 and (NH4)2PtCl6. The uptake rates of the two platinum species were studied, and also their effects on the expression of genes encoding metallothionein and heat-shock protein 70, which are known to be induced by several stress factors. In addition, the differential display technique was used to search for genes that were specifically induced by platinum. A gene for the type I collagen alpha-chain and a novel gene were identified. 相似文献
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Frederico Figueiredo Amancio Tiago Pires Heringer Cristina da Cunha Hueb Barata de Oliveira Liliane Boaventura Fassy Frederico Bruzzi de Carvalho Daniela Pagliari Oliveira Claudio Dornas de Oliveira Fernando Otoni Botoni Fernanda do Carmo Magalh?es José Roberto Lambertucci Mariangela Carneiro 《PloS one》2015,10(6)
The purpose of our study was to describe the clinical profile of dengue-infected patients admitted to Brazilian intensive care units (ICU) and evaluate factors associated with death. A longitudinal, multicenter case series study was conducted with laboratory-confirmed dengue patients admitted to nine Brazilian ICUs situated in Minas Gerais state, southeastern Brazil from January 1, 2008, to December 31, 2013. Demographic, clinical and laboratory data; disease severity scores; and mortality were evaluated. A total of 97 patients were studied. The in-ICU and in-hospital mortality rates were 18.6% and 19.6%, respectively. Patients classified as having severe dengue according to current World Health Organization classifications showed an increased risk of death in a univariate analysis. Nonsurvivors were older, exhibited lower serum albumin concentrations and higher total leukocyte counts and serum creatinine levels. Other risk factors (vomiting, lethargy/restlessness, dyspnea/respiratory distress) were also associated with death in a univariate analysis. Multivariate analysis indicated that in-hospital mortality was significantly associated with Acute Physiology and Chronic Health Evaluation II and the Sequential Organ Failure Assessment score. The ICU and in-hospital mortality observed in this study were higher than values reported in similar studies. An increased frequency of ICU admission due to severe organ dysfunction, higher severity indices and scarcity of ICU beds may partially explain the higher mortality. 相似文献
29.
Ilmara Varotto Roma Neto Renan Augusto Ribeiro Mariangela Hungria 《World journal of microbiology & biotechnology》2010,26(7):1291-1302
Biodiversity of diazotrophic symbiotic bacteria in the tropics is a valuable but still poorly studied resource. The objective
of this study was to determine if a second housekeeping gene, glnII, in addition to the 16S rRNA, can be employed to improve the knowledge about taxonomy and phylogeny of rhizobia. Twenty-three
elite rhizobial strains, very effective in fixing nitrogen with twenty-one herbal and woody legumes (including species from
fourteen tribes in the three subfamilies of the family Leguminosae) were selected for this study; all strains are used as commercial inoculants in Brazil. Complete sequences of the 16S rRNA
and partial sequences (480 bp) of the glnII gene were obtained. The same primers and amplification conditions were successful for sequencing the glnII genes of bacteria belonging to five different rhizobial genera—Bradyrhizobium, Mesorhizobium, Methylobacterium, Rhizobium, Sinorhizobium)—positioned in distantly related branches. The analysis of the concatenated genes (16S rRNA + glnII) considerably improved information about phylogeny and taxonomy of rhizobia in comparison to the single analysis of the 16S
rRNA. Nine strains might belong to new species. The complementary analysis of the glnII gene was successful with all strains and improved the phylogenetic clustering and clarified the taxonomic position of several
strains. The strategy of including the analysis of glnII, in addition to the 16S rRNA, is cost- and time- effective for the characterization of large rhizobial culture collections
or in surveys of many isolates. 相似文献
30.
Little information is available on the functional relationship between bursa and thymus during chicken embryogenesis. We, therefore, investigated embryonic thymuses taken at 17 days in ovo from chickens bursectomized at 68-72 hours, with histological, histochemical (PAS, Alcian blue), and immunoreaction (anti-cytokeratin B, anti-PCNA/cyclin and anti-CD3, CD4 and CD8 antibodies) methods and compared these data with those from normal and sham-operated chickens of the same age. The bursectomized thymuses distinctly differed from normal and sham-operated thymuses: they were smaller, and the cortical zone was thinner and contained fewer epithelial cells and thymocytes. Only few cortical thymocytes were immunoreactive for PCNA, indicating low proliferative rate. More cortical thymocytes as compared with the normal, expressed CD3 on their cell membrane, whereas the thymocytes at the cortical-medullary border expressing anti- CD4 and anti-CD8 antidodies were less numerous than in normal thymus. The medullary zone contained few epithelial clusters made up of fewer cells than medullary clusters in normal chickens. Some cystic formations were enlarged and contained PAS- or Alcian-blue positive amorphous material. All these data suggest that early bursectomy affects both morphological and functional thymic development. 相似文献