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91.
92.
Aims: To facilitate isolation and differentiation of the almost entirely unknown Jeotgalicoccus spp. Methods and Results: Jeotgalicoccus spp. have been found in dust samples using SSCP‐PCR analysis. As the cultivation of strains is necessary for further studies on virulence, pathogenicity or metabolism, we developed a method for cultural isolation and further differentiation of Jeotgalicoccus spp. We found that J. halotolerans, J. psychrophilus, J. marinus, as well as the related species Salinicoccus roseus grow on Baird Parker (BP) agar as black colonies without clear zones. J. pinnipedialis and S. jeotgali grow only weakly on BP agar without forming clearly delineated colonies. On BP agar, the colony‐forming Jeotgalicoccus and Salinicoccus spp. are not distinguishable from coagulase‐negative Staphylococcus spp. (CNS). However, unlike CNS, all of the above mentioned species are unreactive in the OF test. SSCP‐PCR was able to differentiate between all investigated Jeotgalicoccus and Salinicoccus spp., as all species had different band positions. Conclusions: Jeotgalicoccus spp. and Salinicoccus spp. may be widely distributed in the environment, but, until now, overlooked or confused with staphylococci. Further epidemiological studies, which are required to prove this hypothesis, are facilitated by the observations of our study. Significance and Impact: This not yet published information enables researchers to carry out epidemiological studies on Jeotgalicoccus spp. in a very cheap and easy way. 相似文献
93.
Dubin G Popowicz G Krajewski M Potempa J Dubin A Holak TA 《Journal of biomolecular NMR》2004,28(3):295-296
The increasing antibiotic resistance of an important human pathogen Staphylococcus aureus calls for the development of new therapeutic strategies. Staphylococcal cysteine proteases have been suggested as targets for such therapies. The recent discovery of staphostatins, specific protein inhibitors of these enzymes, gives prospects for the design and production of synthetic, low molecular weight analogs which might become drugs. We have decided to structurally characterize staphostatin A, a representative inhibitor of staphylococcal cysteine proteases, and to assess its binding mode to the target protease with the view of clarifying the specificity determinants. Here we report the (1)H, (15)N and (13)C NMR resonance assignments of staphostatin A. 相似文献
94.
95.
Frequently bacteria are exposed to membrane-damaging cationic antimicrobial molecules (CAMs) produced by the host's immune system (defensins, cathelicidins) or by competing microorganisms (bacteriocins). Staphylococcus aureus achieves CAM resistance by modifying anionic phosphatidylglycerol with positively charged L-lysine, resulting in repulsion of the peptides. Inactivation of the novel S. aureus gene, mprF, which is found in many bacterial pathogens, has resulted in the loss of lysylphosphatidylglycerol (L-PG), increased inactivation by CAM-containing neutrophils, and attenuated virulence. We demonstrate here that expression of mprF is sufficient to confer L-PG production in Escherichia coli, which indicates that MprF represents the L-PG synthase. L-PG biosynthesis was studied in vitro and found to be dependent on phosphatidylglycerol and lysyl-tRNA, two putative substrate molecules. Further addition of cadaverin, a competitive inhibitor of the lysyl-tRNA synthetases, or of RNase A abolished L-PG biosynthesis, thereby confirming the involvement of lysyl-tRNA. This study forms the basis for further detailed analyses of L-PG biosynthesis and its role in bacterial infections. 相似文献
96.
As part of a project to characterise plant-derived natural products that modulate bacterial multidrug resistance (MDR), bioassay-guided fractionation of a chloroform extract of the aerial parts of Rosmarinus officinalis led to the characterisation of the known abietane diterpenes carnosic acid (1), carnosol (2) and 12-methoxy-trans-carnosic acid. Additionally, a new diterpene, the cis A/B ring junction isomer of 12-methoxy-trans-carnosic acid, 12-methoxy-cis-carnosic acid (5), was isolated. The major components were assessed for their antibacterial activities against strains of Staphylococcus aureus possessing efflux mechanisms of resistance. Minimum inhibitory concentrations ranged from 16 to 64 microg/ml. Incorporation of 1 and 2 into the growth medium at 10 microg/ml caused a 32- and 16-fold potentiation of the activity of erythromycin against an erythromycin effluxing strain, respectively. Compound 1 was evaluated against a strain of S. aureus possessing the NorA multidrug efflux pump and was shown to inhibit ethidium bromide efflux with an IC50 of 50 microM, but this activity is likely to be related to the inhibition of a pump(s) other than NorA. The antibacterial and efflux inhibitory activities of these natural products make them interesting potential targets for synthesis. 相似文献
97.
Sánchez-Mendoza M. Ortigoza-Ferado J. Barrón-Romero B.L. Mota-de-la-Garza L. 《World journal of microbiology & biotechnology》2001,17(2):211-213
MAb anti-Staphylococcal enterotoxins (MAb-SE) were produced in mice with a mixture of reference SE types A, B, C1 and D at a concentration of 1 g each per mouse; the last booster injection was by intrasplenic route. Nine clones were chosen, two produced anti-SEB and anti-SED, one anti-SEA and anti-SEB, two anti-SED, two anti-SEB and one produced anti-SEC1. The MAb-SE were partially purified as judged by PAGE–SDS. The partially purified antibodies could demonstrate the presence of SE in milk samples containing 0.5 g of toxin m l–1. 相似文献
98.
Microbial characterization during composting of municipal solid waste 总被引:29,自引:0,他引:29
Hassen A Belguith K Jedidi N Cherif A Cherif M Boudabous A 《Bioresource technology》2001,80(3):217-225
This study investigates the prevailing physico-chemical conditions and microbial community; mesophilic bacteria, yeasts and filamentous fungi, bacterial spores, Salmonella and Shigella as well as faecal indicator bacteria: total coliforms, faecal coliforms and faecal Streptococci, present in a compost of municipal solid waste. Investigations were conducted in a semi-industrial pilot plant using a moderate aeration during the composting process. Our results showed that: (i) auto-sterilization induced by relatively high temperatures (60–55°C) caused a significant change in bacterial communities. For instance, Escherichia coli and faecal Streptococci populations decreased, respectively, from 2×107 to 3.1×103 and 107 to 1.5×103 cells/g waste dry weight (WDW); yeasts and filamentous fungi decreased from 4.5×106 to 2.6×103 cells/g WDW and mesophilic bacteria were reduced from 5.8×109 to 1.8×107 bacteria/g WDW. On the other hand, the number of bacterial spores increased at the beginning of the composting process, but after the third week their number decreased notably; (ii) Salmonella disappeared completely from compost by the 25th day as soon as the temperature reached 60°C; and (iii) the bacterial population increased gradually during the cooling phase. While Staphylococci seemed to be the dominant bacteria during the mesophilic phase and at the beginning of the thermophilic phase, bacilli predominated during the remainder of the composting cycle. The appearance of gram-negative rods (opportunistic pathogens) during the cooling phase may represent a serious risk for the sanitary quality of the finished product intended for agronomic reuse. Compost sonication for about 3 min induced the inactivation of delicate bacteria, in particular gram-negatives. By contrast, gram-positive bacteria, especially micrococcus, spores of bacilli, and fungal propagules survived, and reached high concentrations in the compost. 相似文献
99.
100.
Cysteine-319 belongs to the flexible flap at the active site of Proteus vulgaris urease. Replacing this cysteine by threonine resulted in a 20-fold increase of specific activity. Temperature stability increased, susceptibility to inhibition by dipyridyl disulfide decreased, and pH optimum shifted from 8 to 6.9. K
m (35 to 12 mM) and Vmax (47.4 to 1.8 mol min–1) were substancially altered. Both variants of the enzyme were irreversibly inhibited by phenylmethanesulfonyl fluoride. 相似文献