Surveillance and control of rabies in La Reunion,Mayotte, and Madagascar

Mayotte and La Reunion islands are currently free of animal rabies and surveillance is performed by the French Human and Veterinary Public Health Services. However, dog rabies is still enzootic in Madagascar with 4 to 10 confirmed human cases each year. The number of antirabies medical centres in Madagascar is still scarce to provide easy access to the local population for post-exposure rabies prophylaxis. Furthermore, stray dog populations are considerable and attempts to control rabies by mass campaigns of dog vaccination have not received sufficient attention from the national health authorities. To address these challenges, an expanded program to control rabies needs to be initiated by the Malagasy authorities.     

Bartonellae in animals and vectors in New Caledonia

Bartonellae are gram-negative facultative intracellular alpha-proteobacteria from the family Bartonellaceae. The natural history of bartonellae consists of a reservoir/host, which is a vertebrate with chronic intravascular infection with sustained bacteremia, and a vector (usually an arthropod) that transfers the bacteria from the reservoir to a susceptible yet uninfected host. In order to reveal the sources and reservoirs of Bartonella infection in animals and vectors in New Caledonia, we collected the blood samples of 64 dogs, 8 cats, 30 bovines, 25 horses and 29 wild deer Cervus timorensis russa and 308 associated blood-sucking parasites (14 keds Hippobosca equina, 258 ticks (22 Rhipicephalus microplus, 235 Rhipicephalus sanguineus, and 1 Haemaphysalis longicornis), 12 fleas Ctenocephalides felis and 24 dog lice Trichodectes canis). We isolated ten strains of Bartonella: four Bartonella henselae from cats and six Bartonella chomelii from cattle. The strains were characterized by sequencing of five genes (16S, ITS, rpoB, gltA and ftsZ). The six strains isolated from cattle were close to the reference strain of B. chomelii and were, probably, imported from France with cattle of Limousin race. PCR showed that 35% of keds collected from deer and 31% of deer were infected by B. aff. schoenbuchensis; all other samples were negative. Our data confirmed that in New Caledonia, as in other regions of the world, cats are the major reservoirs of B. henselae. We also confirmed that Hippoboscidae flies may serve as the vectors of ruminant-associated bartonellae.     

LHYMO: A new Water Framework Directive-compliant multimetric index to assess lake hydromorphology and its application to French lakes

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Serotypes of Streptococcus agalactiae cultured from dairy milk samples in Québec

Streptococcus agalactiae remains an important pathogen of dairy herds in Québec, but data about antigenic characteristics of this microorganism are sparse. This study was conducted to determine the variety of S. agalactiae serotypes in dairy herds in Québec. Two hundred and ninety-five isolates cultured from the milk of individual cows from 7 regions of Québec were serotyped. Sixty-two percent of the isolates were untypable. Among the 38% of typeable isolates, serotype III was found most frequently. In conclusion, the heterogeneity found among antigenic determinants of isolates from bovine milk suggests that an immunological method for the detection of S. agalactiae performed directly on bovine milk would not be a practical approach.     

Structural characterization of the major flavonoid glycosides from Arabidopsis thaliana seeds

Information gains from the seed of the model plant Arabidopsis thaliana (Brassicaceae) have greatly contributed to a better understanding of flavonoid synthesis and may be used for crop improvement. However, exhaustive identification of the flavonoid accumulated in Arabidopsis seed was still lacking. Complementary investigations of seed flavonoids by LC-ESI-MS, LC-ESI-MS-MS, and NMR spectroscopy in Arabidopsis led to full characterization of monoglycosides, namely, quercetin 3-O-alpha-rhamnopyranoside and kaempferol 3-O-alpha-rhamnopyranoside, and diglycosides, namely, quercetin and kaempferol 3-O-beta-glucopyranoside-7-O-alpha-rhamnopyranoside and quercetin and kaempferol 3,7-di-O-alpha-rhamnopyranoside. Interestingly, the tt7 mutant that lacks flavonoid-3'-hydroxylase and consequently accumulates only kaempferol derivatives was shown to contain three additional products, kaempferol 3-O-beta-glucopyranoside, kaempferol 3-O-alpha-rhamnopyranoside-7-O-beta-glucopyranoside, and the triglycoside kaempferol 3-O-beta-[alpha-rhamnopyranosyl(1-->2)-glucopyranoside]-7-O-alpha-rhamnopyranoside. Taken together these results allow a scheme for flavonol glycosylation to be proposed.     

Changes in proanthocyanidin chain length in winelike model solutions

Reactions of seed and skin proanthocyanidins in the presence or absence of (-)-epicatechin were followed in winelike solutions over 53 days at 30 degrees C. Proanthocyanidins were separated from flavanol monomers by sequential elution from a Sep Pak cartridge, and changes in proanthocyanidin composition were monitored by thiolysis analysis of the proanthocyanidin fraction. In solutions containing no free (-)-epicatechin, trace amounts of monomers were released and important losses of proanthocyanidins were measured, but their average composition and mean degree of polymerization (mDP) were hardly modified. In the presence of (-)-epicatechin, the mDP value decreased and oligomeric proanthocyanidins accumulated throughout the incubation while losses of total units were dramatically reduced. Our data indicate that interflavanic bond cleavage of proanthocyanidins occurred under mild acidic conditions such as encountered in wine and that the resulting carbocation proceeded to unknown species. The latter reaction did not take place in the presence of (-)-epicatechin. Epicatechin added to the intermediate carbocation, thus being incorporated as the end unit of a shorter proanthocyanidin chain. The results of this study are discussed in relation to the loss of astringency reported during wine aging.     

The substrate of Greatwall kinase, Arpp19, controls mitosis by inhibiting protein phosphatase 2A

Initiation and maintenance of mitosis require the activation of protein kinase cyclin B-Cdc2 and the inhibition of protein phosphatase 2A (PP2A), which, respectively, phosphorylate and dephosphorylate mitotic substrates. The protein kinase Greatwall (Gwl) is required to maintain mitosis through PP2A inhibition. We describe how Gwl activation results in PP2A inhibition. We identified cyclic adenosine monophosphate-regulated phosphoprotein 19 (Arpp19) and α-Endosulfine as two substrates of Gwl that, when phosphorylated by this kinase, associate with and inhibit PP2A, thus promoting mitotic entry. Conversely, in the absence of Gwl activity, Arpp19 and α-Endosulfine are dephosphorylated and lose their capacity to bind and inhibit PP2A. Although both proteins can inhibit PP2A, endogenous Arpp19, but not α-Endosulfine, is responsible for PP2A inhibition at mitotic entry in Xenopus egg extracts.     

Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by a new cytometric assay

The adhesion of methyl ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is promising for various applications concerning the study of interactions between microorganisms and an emulsified hydrophobic substrates.     

Carbon and nitrogen mobilization in Larix x eurolepis leafy stem cuttings assessed by dual (13)C and (15)N labeling: relationships with rooting

Changes in use of both stored and newly synthesized sources of carbon (C) and nitrogen (N) were investigated during rooting of leafy cuttings of Larix x eurolepis A. Henry. We used dual (13)C and (15)N long-term labeling of reserves of stock plants and followed isotope dilution of the labels in the cuttings to determine the respective proportions of C and N derived from stock plant reserves (Q(C,old), Q(N,old)) and from newly synthesized sources (Q(C,new), Q(N,new)). We also assessed their partitioning into the growing needles and roots. Because rooting development occurred over several months, destructive harvests were made during three periods (t(0): April 9; t(1): May 15 to June 5; t(2): June 12 to June 26). Total C content (Q(C)) of cuttings did not change with time, whereas total N content (Q(N)) decreased significantly between t(0) and t(2). In rooted cuttings, unlike unrooted cuttings, total N concentration decreased less markedly in needles and in the lower stem component between t(1) and t(2) than between t(0) and t(2). The lower stem of rooted cuttings contained more Q(N,old) than that of unrooted cuttings and showed lower C:N and (13)C:(15)N ratios. The increase in Q(N,new) in the lower stem was positively correlated with rooting status. At t(1), new roots appeared and grew mainly at the expense of Q(C,new) and Q(N,old). By t(2), root growth was mainly dependent on new assimilates. We conclude that in leafy cuttings the initial amount of N reserves, rather than C reserves, may constitute a limiting factor for rooting.