Nucleotide sequence of a cloned cDNA corresponding to secreted mu chain of mouse immunoglobulin

The cDNA complementary to a mouse immunoglobulin mu heavy chain mRNA has been cloned into the PstI site of the plasmid vector pBR322. A hybrid plasmid pmu 183.5 containing a 1850 bp insert has been selected by differential screening. The nucleotide sequence of the inset encodes the four constant domains, the terminal piece and the 3'-untranslated region.     

Characterization of Lactobacillus collinoides response to heat, acid and ethanol treatments

Tolerance to stress and cross-protection in Lactobacillus collinoides were examined after exposure to ethanol, acid or heat shock. Ethanol and heat-adapted cells demonstrate induced homologous␣tolerance and cross-resistance to acid stress. No cross-protection of acid-adapted cells against ethanol and heat stresses was observed. Heat was the only pretreatment leading to cross-protection against the two other stresses. Whole-cell protein extract analysis revealed that each treatment induced a battery of stress proteins; the synthesis of some of these polypeptides being induced by more than one condition. The greatest overlap was observed between ethanol and heat treatments. Ten proteins were found to be common to these stresses. Received: 7 November 1998 / Received revision: 10 February 1999 / Accepted: 12 February 1999     

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.     

Assignment of the chicken tyrosine hydroxylase gene to chromosome 6 by FISH.

The gene for tyrosine hydroxylase, the first and rate-limiting enzyme in the biosynthetic pathway of catecholamine neurotransmitters, has been localized in situ to chromosome 6 in the chicken. It is the first DNA marker to be reported for this telocentric macrochromosome. Use of a 45-kb biotinylated chicken-specific cosmid probe and a sensitive fluorescent detection system proved to be highly efficient, with over 90% of metaphases showing positive hybridization signals on one or (usually) both chromosome 6 homologs, in physically mapping this single-gene locus.     

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