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71.
AIMS: To investigate intracellular localization of nickel and its chemical nature in Pseudomonas aeruginosa. METHODS AND RESULTS: Transmission electron micrographs of Ni-loaded bacteria exhibited a darkened electron opaque zone throughout the cell periphery. Energy dispersive X-ray analysis confirmed the deposition of metallic nickel. Cell fractionation revealed that 88% of the accumulated nickel was restricted to the periplasm and membrane. X-ray diffraction patterns ascertained the chemical nature of cellular Ni as phosphide (Ni5P4, NiP2 and Ni12P5) and carbide (Ni3C) crystals. CONCLUSION: Pseudomonas aeruginosa accumulated nickel as its phosphide and carbide crystal mostly in the cell envelope region, indicating the predominant role of phosphoryl and carboxyl/carbonyl groups of cell wall/membrane components in cation sequestration. SIGNIFICANCE AND IMPACT OF THE STUDY: The data contribute significantly to a better understanding of bacteria-metal interaction and will be useful in developing biotechnological strategies for toxic metal bioremediation. 相似文献
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Gulen Irem Kaya Buket Sar?kaya Mustafa Ali Onur Nehir Unver Somer Francesc Viladomat Carles Codina Jaume Bastida Ina L. Lauinger Marcel Kaiser Deniz Tasdemir 《Phytochemistry letters》2011,4(3):301-305
Two new alkaloid N-oxides, 1-O-acetyldihydromethylpseudolycorine N-oxide, and 11-hydroxyvittatine N-oxide, ten known alkaloids; arolycoricidine, haemanthamine, O-methylnorbelladine, narcidine, dihydrolycorine, 8-O-demethylmaritidine, stylopine and protopine, nicotinic acid and tyramine were isolated from Galanthus trojanus A.P. Davis & N. Özhatay (Amaryllidaceae). The chemical structures of the isolates were elucidated by UV, IR, MS, CD, 1D and 2D NMR experiments. The in vitro antiprotozoal and cytotoxic potentials of the compounds were also evaluated. 相似文献
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A. Mahanti I. Samanta S. Bandopaddhay S.N. Joardar T.K. Dutta S. Batabyal T.K. Sar D.P. Isore 《Letters in applied microbiology》2013,56(4):291-298
In total, 363 Escherichia coli were isolated from 165 faecal samples of healthy buffaloes in West Bengal, India. Twenty‐four of these isolates (6·61%) were found to carry at least one gene characteristic for Shiga toxin–producing Escherichia coli (STEC). These STEC strains belonged to 13 different O‐serogroups. The stx1 gene was present in 23 (95·8%) of total STEC isolates, whereas 20 (83·3%) STEC isolates carried the gene stx2. Twelve strains of E. coli (50% of total STEC isolates) possessed enterohaemolysin (ehxA) gene in combination with others. Fourteen (58·33%) isolates found to possess saa gene. However, no E. coli was detected harbouring gene for intimin protein (eaeA). Of 23 stx1‐positive isolates, seven (30·43%) were positive for genes of the stx1C subtype. Of the 20 isolates with the stx2 gene, 25% (5/20) possessed stx2C and 10% (2/20) possessed stx2d gene. The phylogenetic analysis after RAPD of STEC strains revealed six major clusters. The isolated STEC strains were resistant most frequently to erythromycin (95·83%), cephalothin (62·5%), amikacin (54·17%), kanamycin (45·83%) and gentamicin (41·67%) group of antibiotics. No ESBL‐producing (blaCTXM, blaTEM, blaSHV) or quinolone resistance gene (qnrA) was detected in the STEC isolates.
Significance and Impact of the Study
The buffaloes from different districts of West Bengal, India, are important reservoir of multidrug‐resistant Shiga toxin–producing Escherichia coli (STEC). India is home to more than 56% of world buffalo population, traditionally raised by farmers. So, there is a major risk of transmission of STEC among the human population of this part of the globe. However, there is no prevalence study of STEC from healthy or diarrhoeic buffalo in India. The present study reports for the first time in India about isolation, molecular characterization and antibiotic resistance pattern of STEC in healthy buffaloes. 相似文献76.
Kheng Chheng Michael J. Carter Kate Emary Ngoun Chanpheaktra Catrin E. Moore Nicole Stoesser Hor Putchhat Soeng Sona Sin Reaksmey Paul Kitsutani Borann Sar H. Rogier van Doorn Nguyen Hanh Uyen Le Van Tan Daniel Paris Stuart D. Blacksell Premjit Amornchai Vanaporn Wuthiekanun Christopher M. Parry Nicholas P. J. Day Varun Kumar 《PloS one》2013,8(4)
BackgroundFebrile illnesses are pre-eminent contributors to morbidity and mortality among children in South-East Asia but the causes are poorly understood. We determined the causes of fever in children hospitalised in Siem Reap province, Cambodia.ConclusionWe identified a microbiological cause of fever in almost 50% of episodes in this large study of community-acquired febrile illness in hospitalized children in Cambodia. The range of pathogens, antimicrobial susceptibility, and co-morbidities associated with mortality described will be of use in the development of rational guidelines for infectious disease treatment and control in Cambodia and South-East Asia. 相似文献
77.
The study aimed to determine the reproductive characteristics of the broad‐snout Chondrostoma holmwoodii population (spawning season, number of eggs and first age of sexual maturity) in order to assess the population status in the Tahtal? Dam Lake reservoir. A total of 1208 specimens were examined of which 72.1% were females and 27.9% males (female:male ratio = 1 : 0.40); the percentage of males, however, declined in the higher age classes (IV and V). The monthly determined gonadosomatic index indicated that the peak reproduction period of the species is in April and early May. The study covered age classes I–V, with specimens at age II reaching maturity. The total number of eggs per female varied from 8000 to 41 700, the mean number of eggs increasing proportionally with age of the spawner. Egg diameters also increased during the 5‐month ripening period from December to April. 相似文献
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Aniek D. van der Woude Esther J. M. Stoop Michael Stiess Sen Wang Roy Ummels Gunny van Stempvoort Sander R. Piersma Alessandro Cascioferro Connie R. Jiménez Edith N. G. Houben Joen Luirink Jean Pieters Astrid M. van der Sar Wilbert Bitter 《Cellular microbiology》2014,16(2):280-295
The pathogenicity of mycobacteria is closely associated with their ability to export virulence factors. For this purpose, mycobacteria possess different protein secretion systems, including the accessory Sec translocation pathway, SecA2. Although this pathway is associated with intracellular survival and virulence, the SecA2‐dependent effector proteins remain largely undefined. In this work, we studied a Mycobacterium marinum secA2 mutant with an impaired capacity to initiate granuloma formation in zebrafish embryos. By comparing the proteomic profile of cell envelope fractions from the secA2 mutant with wild type M. marinum, we identified putative SecA2‐dependent substrates. Immunoblotting procedures confirmed SecA2‐dependent membrane localization for several of these proteins, including the virulence factor protein kinase G (PknG). Interestingly, phenotypical defects of the secA2 mutant are similar to those described for ΔpknG, including phagosomal maturation. Overexpression of PknG in the secA2 mutant restored its localization to the cell envelope. Importantly, PknG‐overexpression also partially restored the virulence of the secA2 mutant, as indicated by enhanced infectivity in zebrafish embryos and restored inhibition of phagosomal maturation. These results suggest that SecA2‐dependent membrane localization of PknG is an important determinant for M. marinum virulence. 相似文献
80.
Srey Viseth Horm Sek Mardy Sareth Rith Sovann Ly Seng Heng Sirenda Vong Paul Kitsutani Vannra Ieng Arnaud Tarantola Sowath Ly Borann Sar Nora Chea Buth Sokhal Ian Barr Anne Kelso Paul F. Horwood Ans Timmermans Aeron Hurt Chanthap Lon David Saunders Sam An Ung Nima Asgari Maria Concepcion Roces Sok Touch Naomi Komadina Philippe Buchy 《PloS one》2014,9(10)