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141.
S. Flahaut Abdellah Benachour Jean-Christophe Giard Philippe Boutibonnes Yanick Auffray 《Archives of microbiology》1996,165(5):317-324
Enterococcus faecalis was strongly resistant to high osmotic pressure in complex medium; however, when it was subjected to a moderate osmotic stress
[6.5% (w/v) NaCl or 52% (w/v) sucrose] for 2 h, it showed cross-protection against ethanol (22%), detergents stresses [bile
salts (0.3%) and SDS (0.017%)], hydrogen peroxide challenge (45 mM), and to a minor extent against lethal temperature (62° C).
In response to salt stress [6.5% (w/v) NaCl], E. faecalis induced a large number of stress proteins. In addition, NaCl strongly induced the synthesis of many proteins more than tenfold.
Although the acquired thermotolerance was inhibited markedly by chloramphenicol, the other NaCl-induced cross-tolerances seemed
not to be correlated with de novo protein synthesis. The relationship between the stress protein synthesis and the induction
of different types of cross-protection is discussed.
Received: 7 September 1995 / Accepted: 29 January 1996 相似文献
142.
A detailed study of the upper Pleistocene and Holocene ostracode fauna from the Moroccan margin of the Western Mediterranean is here presented based on sediments of three cores drilled near the Straits of Gibraltar (Sea of Alboran), between 300 and 550 m of depth. Information on the quantitative and qualitative distribution of the ostracodes was obtained, for the first time, in this area. This study also allowed to identify recall the main climatic and eustatic variations as recorded in the sediments and the faunal composition and to identify the corresponding chronological limits from the last glacial maximum to the present time. 相似文献
143.
From photosynthetic studies on a range of monocotyledonous (C-3 and C-4) and dicotyledonous (C-3) plants using a leaf oxygen electrode, we conclude the following. (i) A non-linear model [J.H.M. Thornley (1976) Mathematical models in plant physiology, Academic Press, London; B. Marshall and P.V. Biscoe (1980) J Exp Bot 31:29-39] significantly better describes the photosynthetic light response curve [rate of photosynthesis (P) versus incident photosynthetic photon flux density (I)] than the frequently used linear hyperbolic model [E.I. Rabinowich (1951) Photosynthesis and related processes, vol 2, Wiley, New York]. (ii) When used at the recommended CO2 partial pressures (Ca = 1-5 kPa), CO2 supply saturates the photosynthesis rate in the C-3 dicot Phaseolus coccineus L. but not in the C-3 monocot Hordeum vulgare L.. (iii) Fits using a linear hyperbolic model for P versus I produce relatively large and statistically significant errors (approximately 60%) in the estimation of Pmax and quantum efficiency (alpha) if Ca is not > 5 kPa. (iv) The convexity term, theta, incorporated into the non-linear models for P versus I appears to reflect the limitation placed on the carboxylation processes by the supply of CO2 to the chloroplast stroma. Therefore, the use of a non-linear model providing an estimate of theta should be encouraged, as it is likely to provide information on the physiological status of plants. 相似文献
144.
Mahmud Bani-Yaghoub Roger G Tremblay Abdellah Ajji Munyao Nzau Sandhya Gangaraju David Chitty Bogdan Zurakowski Marianna Sikorska 《Biochimie et biologie cellulaire》2008,86(5):361-369
Every year thousands of people suffer from brain injuries and stroke, and develop motor, sensory, and cognitive problems as a result of neuronal loss in the brain. Unfortunately, the damaged brain has a limited ability to enact repair and current modes of treatment are not sufficient to offset the damage. An extensive list of growth factors, neurotrophic factors, cytokines, and drugs has been explored as potential therapies. However, only a limited number of them may actually have the potential to effectively offset the brain injury or stroke-related problems. One of the treatments considered for future brain repair is bone morphogenetic protein 7 (BMP7), a factor currently used in patients to treat non-neurological diseases. The clinical application of BMP7 is based on its neuroprotective role in stroke animal models. This paper reviews the current approaches considered for brain repair and discusses the novel convergent strategies by which BMP7 potentially can induce neuroregeneration. 相似文献
145.
Jean-Christophe Giard Axel Hartke Sigrid Flahaut Abdellah Benachour Philippe Boutibonnes Yanick Auffray 《Current microbiology》1996,32(5):264-271
Compared with growing bacteria, carbohydrate-starved cells of Enterococcus faecalis show development of a multiresistance state against heat, H2O2, acid, and ethanol, but not against UV irradiation. The kinetics of acquisition of resistance is different according to the
stress. Three hours of starvation provide maximal resistance against ethanol, while the tolerance to heat, H2O2, and acid increases progressively with the duration of starvation. Chloramphenicol treatment does not abolish the ethanol
tolerance. Protein synthesis inhibition during the transitional growth phase and the first hours of starvation partially inhibit
the acquisition of heat and oxidative resistances. Antibiotic treatment after 3 h of starvation does not affect the increase
of these resistances. We suggest that synthesis of specific proteins revealed by 2-D gel analysis in the first 3 h of starvation,
followed by a second mechanism related to protein degradation or alteration, is necessary for acquisition of maximal resistance
towards heat and oxidative stresses. 相似文献
146.
Abdellah Benachour Sigrid Flahaut Jacques Frère Georges Novel 《Current microbiology》1996,32(4):188-194
Various strains of Pediococcus genus were successfully transformed by electroporation using the broad host-range plasmid pSA3 and the lactococcal Rep22
based-replicon pUCB304. Failure to transform Tetragenococcus strains by electroporation have led to use conjugation as an alternative plasmid DNA transfer mechanism. Intergeneric matings
conducted with the broad host-range conjugative plasmid pVA797 from Lactococcus lactis subsp. lactis SL2/797A to Tetragenococcus halophilus and Pediococcus pentosaceus strains have shown that Tetragenococcus strains are not impervious to plasmid DNA transfer. Plasmid and metabolic profiles of wild and mutant strains of Pediococcus pentosaceus NCDO990 have shown that many metabolic traits including lactose utilization are plasmid linked. 相似文献
147.
Axel Hartke Sandrine Bouché Jean-Christophe Giard Abdellah Benachour Philippe Boutibonnes Yanick Auffray 《Current microbiology》1996,33(3):194-199
The lactic acid tolerance response (LATR) of the lactic acid bacterium Lactococcus lactis subsp. lactis has been studied. A dramatic increase in survival to a severe acid stress (pH 3.9) was obtained by preexposing the cells
for 30 min to a mildly acid shock at pH 5.5. Whole-cell protein extract analysis revealed that during the acid tolerance response
33 polypeptides are induced over the level of naive cells. Among these are the major heat shock proteins DnaK and GroEL. In
conjunction with a previous report (Hartke et al. 1994), the results establish that L. lactis can adapt to lactic acid exposure in two different ways: a logarithmic phase LATR, which may be activated by protons, and
a stationary-phase LATR, which needs no activation by protons. Both systems are independent of de novo protein synthesis.
Received: 8 February 1996 / Accepted: 11 March 1996 相似文献