Starvation-Induced Multiresistance in Enterococcus faecalis JH2-2

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.     

Plasmid Transfer by Electroporation and Conjugation in Tetragenococcus and Pediococcus Genera and Evidence of Plasmid-Linked Metabolic Traits

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.     

Possible gastrointestinal disorders for athletes during Ramadan: an overview

Ramadan is considered to be the month of the stomach break. It has been reported that Ramadan has some health benefits. In most Muslims countries, there is a huge modification in the diet during this month. These changes could induce some gastrointestinal (GI) disorders (e.g. diarrhea, cramps, fullness, nausea). The aims of the present overview were to present some challenges that could be observed for athletes during the training sessions or competition and present some practical recommendations to avoid GI disorders during Ramadan. Based on previous studies, we could advance that the prevalence of GI disorders will be more pronounced when athletes travel for international competitions during Ramadan. Besides, GI disorders are more frequent for athletes when there is a huge modification in the training load. Dehydration observed during Ramadan is one of the factors that may induce GI disorders. The latter could be exacerbated by sweat loss during training sessions. Carbohydrate is frequently used by athletes to improve performance and is associated with some GI disorders. Therefore, during Ramadan, coaches and athletes should be advised to maintain the same diet and a good hydration as before the fasting month, and avoid air travel when preparing for competitions.     

The Lactic Acid Stress Response of Lactococcus lactis subsp. lactis

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