New insight about the functionality of oenological tannins; Main results of the working group on oenological tannins

This communication synthetize all the results obtained by the OIV working group on oenological tannins to the current date. The obtained results confirm that oenological tannins really exert a protection effect against grape juice and wine oxidation because they have antioxidant activity, they consume directly oxygen and they exert an inhibitory effect on the laccase activity. Moreover, oenological tannins also exert a copigmentation effect which can improve and protect de color of red wines

Rythmes d'activité chez le hérisson au cours de l'hibernation

The body temperature (Tb) of both male and female hedgehogs living under natural climatic conditions was measured during the whole hibernation period (September to March). Three successive phases were distinguished : (1) the pre-hibernation phase (September-October) was characterized by short spontaneous hypothermic bouts ; (2) the hibernation phase (from the end of October onwards) showed an alternation of long deep torpor bouts (up to 10 days in males and 14 days in females) and short spontaneous arousals (6 to 72 hours) ; (3) the final phase corresponded to the last arousal and occurred earlier in males (January-February) than in females (end of February-beginning of March). Tb was shown to vary with Ta. Concerning the light-dark cycles, the entries in torpor occurred more often at night (75 %) and the arousals in the day-time (73 %). The analysis of food consumption emphasized that hedgehogs still fed during the pre-hibernation phase, fasted during the hibernation phase, and fed again regularly from the last arousal. These results were related to energetics of hibernation as hedgehogs spent about 80 % of their time in hypothermia (= energy economy) and 20 % only in euthermia (= energy expenditure corresponding to body mass loss).Vignault M.-P., Saboureau M. Rythmes d'activité chez le hérisson au cours de l'hibernation. In: Revue d'Écologie (La Terre et La Vie), tome 48, n°2, 1993. pp. 109-119

Activity rhythms of hibernating hedgehogs

The body temperature (Tb) of both male and female hedgehogs living under natural climatic conditions was measured during the whole hibernation period (September to March). Three successive phases were distinguished: (1) the pre-hibernation phase (September-October) was characterized by short spontaneous hypothermic bouts; (2) the hibernation phase (from the end of October onwards) showed an alternation of long deep torpor bouts (up to 10 days in males and 14 days in females) and short spontaneous arousals (6 to 72 hours); (3) the final phase corresponded to the last arousal and occurred earlier in males (January-February) than in females (end of February-beginning of March

Complete nucleotide sequence of the genome of Spiroplasma citri virus SpV1-R8A2 B.

International audienc

Influence of two prefermentative treatments to reduce the ethanol content and pH of red wines obtained from overripe grapes

This study researches treatments for reducing the ethanol content and pH of wine, by either adding or replacing a portion of overripe red grape juice with acidified water or with a white grape juice of low potential ethanol content previously treated with cationic exchange. All treatments resulted in wines with lower ethanol content; however, the treatments did not always correct wine acidity effectively and sometimes the wine composition was negatively affected because the other wine components were diluted. Specifically, both adding and substituting with acidified water caused an increase in wine pH and a general dilution of the other wine components, particularly when the water was added. In contrast, adding acidified must, unlike acidified water, significantly reduced wine pH and the dilution effect was lower, especially when a portion of the original must was replaced by a low sugar content white must treated by cationic exchange. Moreover, this practice is not unauthorized and seems not to affect, but rather improve, the sensory quality of the wine

Characterization of the recA gene regions of Spiroplasma citri and Spiroplasma melliferum

In previous studies (A. Marais, J. M. Bove, and J. Renaudin, J. Bacteriol. 178:862-870, 1996), we have shown that the recA gene of Spiroplasma citri R8A2 was restricted to the first 390 nucleotides of the N-terminal part. PCR amplification and sequencing studies of five additional strains of S. citri have revealed that these strains had the same organization at the recA region as the R8A2 strain. In contrast to S. citri, Spiroplasma melliferum was found to contain a full-length recA gene. However, in all five S. melliferum strains tested, a TAA stop codon was found within the N-terminal region of the recA reading frame. Our results suggest that S. melliferum, as well as S. citri, is RecA deficient. In agreement with the recA mutant genotype of S. citri and S. melliferum, we have shown that these organisms are highly sensitive to UV irradiation

The repetitive domain of ScARP3d triggers entry of Spiroplasma citri into cultured cells of the vector Circulifer haematoceps.

Spiroplasma citri is a plant pathogenic mollicute transmitted by the leafhopper vector Circulifer haematoceps. Successful transmission requires the spiroplasmas to cross the intestinal epithelium and salivary gland barriers through endocytosis mediated by receptor-ligand interactions. To characterize these interactions we studied the adhesion and invasion capabilities of a S. citri mutant using the Ciha-1 leafhopper cell line. S. citri GII3 wild-type contains 7 plasmids, 5 of which (pSci1 to 5) encode 8 related adhesins (ScARPs). As compared to the wild-type strain GII3, the S. citri mutant G/6 lacking pSci1 to 5 was affected in its ability to adhere and enter into the Ciha-1 cells. Proteolysis analyses, Triton X-114 partitioning and agglutination assays showed that the N-terminal part of ScARP3d, consisting of repeated sequences, was exposed to the spiroplasma surface whereas the C-terminal part was anchored into the membrane. Latex beads cytadherence assays showed the ScARP3d repeat domain (Rep3d) to be involved, and internalization of the Rep3d-coated beads to be actin-dependent. These data suggested that ScARP3d, via its Rep3d domain, was implicated in adhesion of S. citri GII3 to insect cells. Inhibition tests using anti-Rep3d antibodies and competitive assays with recombinant Rep3d both resulted in a decrease of insect cells invasion by the spiroplasmas. Unexpectedly, treatment of Ciha-1 cells with the actin polymerisation inhibitor cytochalasin D increased adhesion and consequently entry of S. citri GII3. For the ScARPs-less mutant G/6, only adhesion was enhanced though to a lesser extent following cytochalasin D treatment. All together these results strongly suggest a role of ScARPs, and particularly ScARP3d, in adhesion and invasion of the leafhopper cells by S. citri