Active monitoring of EBLV infection in natural colonies of the mouse-eared Bat (Myotis myotis).

Bats are important reservoir hosts of RNA viruses, including lyssaviruses, which can cross the species barrier to infect humans and other domestic and wild non-flying mammals. Six of the seven Lyssavirus genotypes described to date infect bats. In Europe, two genotypes of Lyssavirus, European bat Lyssavirus types 1 and 2 (EBLV-1 and EBLV-2), circulate among several bat species and numerous bats are found infected every year. To provide epidemiologists and public health officials with data to effectively implement public health measures, we have undertaken field studies to identify the temporal dynamics of virus infection in bat colonies by combining multidisciplinary approaches. We have focused our work on a long-term longitudinal survey of different bat colonies in the Balearic Islands. The prevalence of virus RNA and neutralizing antibodies were analysed in captured bats. The bats were banded to allow for individual monitoring of infection and movements between colonies. The results show different lyssavirus infection episodes across the twelve years of study and provide the first evidence that mortality of the mouse-eared bat (Myotis myotis) in their natural environment does not increase significantly after episodes of EBLV-1 infection.

Sexual dimorphism in the adrenergic control of rat brown adipose tissue response to overfeeding.

Gender-related differences in the brown adipose tissue (BAT) response to overfeeding rats on a cafeteria diet were studied by assessing the balance between the expression of beta-adrenoceptors (beta1-, beta2-, beta3-AR) and alpha2A-AR and their relation to the expression of uncoupling proteins (UCP1, UCP2, UCP3). Cafeteria diet feeding for 15 days, which involved a similar degree of hyperphagia in both sexes, led to a greater body weight excess in females than in males and a lower activation of thermogenesis. Gender-related differences were found for different adrenoceptor expression and protein levels, which might explain, in part, sex differences in the thermogenic parameters. The lower expression of alpha2A-AR in females than in males could be responsible for the higher expression of UCP1 and thermogenic capacity under non-hyperphagic conditions. However, in a situation of high adrenergic stimulation--as occurs with overfeeding--as there is a preferential recruitment of the beta3-AR by noradrenaline compared with other adrenergic receptors, the higher levels of beta3-AR in males rats than in females could be responsible for the greater thermogenic capacity and the lesser weight gain in males. Thus, the alpha2/beta3 balance in BAT could be a key in the thermogenic control.

Composition and structure of helminth communities in two populations of Pipistrellus pipistrellus (Chiroptera: Vespertilionidae) from Spain.

The community composition and structure of helminths of Pipistrellus pipistrellus (Schreber, 1774) from two widely separated Spanish localities, El Saler (n = 42) and the San Pedro pothole (n = 34), were determined and compared. Five species of trematodes, Plagiorchis (Plagiorchis) sp., Lecithodendrium (Lecithodendrium) linstowi Dollfus, 1931, Prosthodendrium (Prosthodendrium) sp., Pycnoporus heteroporus (Dujardin, 1845) and Parabascus semisquamosus (Braun, 1900), and one species of cestode, Hymenolepis pipistrelli López-Neyra, 1941, were found. The two bat populations harboured the same helminth species and showed the same trematode dominance, but the most important differences between the two helminth community structures were attributable to L. (L.) linstowi and H. pipistrelli. The mean species richness in the two localities was not significantly different. The mean number of helminth species per infected bat, mean infracommunity abundance and mean infracommunity diversity showed significant differences between both localities. The number of helminths per bat in both populations displayed an aggregated distribution. Results indicate that the different characteristics of the P. pipistrellus foraging area in both localities are important in determining the composition and structure of helminth communities in this bat species. This is the first study of a Palaearctic bat helminth community.

Effects of cafeteria diet feeding on beta3-adrenoceptor expression and lipolytic activity in white adipose tissue of male and female rats.

OBJECTIVE: To investigate the effects of short term (15 days) cafeteria diet feeding on the expression of beta3-AR in vivo and its association with lipolytic stimulation induced by beta3-AR agonist CGP12177A in isolated white adipocytes. ANIMALS: Six female and 6 male Wistar rats (at 4 weeks of age) were fed on a cafeteria diet plus standard diet for 15 days. The remaining 12 age- and sex-matched rats always received standard diet only. MEASUREMENTS: White gonadal adipose tissue was isolated and used for the determination of beta3-AR and leptin expression, and for in vitro studies of lipolytic activity. RESULTS: Control male rats had higher levels of both beta3-AR and leptin mRNA in white adipose tissue than their female counterparts. Both male and female rats up-regulated the levels of both beta3-AR and leptin mRNA in response to 15 day cafeteria diet feeding. Noradrenaline- and isoprenaline-induced lipolysis were significantly increased in fat cells from control females compared to their male counterparts. CGP12177A stimulation resulted in significantly higher glycerol release in fat cells from cafeteria diet-fed female rats, whereas there were no differences due to dietary treatment in male rats. The maximal lipolytic response of forskolin (stimulating adenylyl cyclase) and dibutyryl cyclic AMP (cyclic AMP analogous) was not affected by sex or cafeteria diet feeding. CONCLUSION: Cafeteria diet feeding brings about higher excess body weight and impaired adipose tissue lipolytic activity in female rats compared to male rats. Thus, the higher levels of beta3-AR mRNA induced by cafeteria feeding are not indicative per se of an increase of the lipolytic response of the adipocytes. The changes seen in other adrenoceptor subtypes (beta1 and beta2) may be more determinant of the overall lipolytic response of adipocytes.

Evolution of European bat lyssaviruses.

Forty-seven European bat lyssaviruses (EBL) and two African insectivorous bat lyssaviruses (Duvenhage viruses) were selected for a comparison to be made of their evolutionary relationships. Studies were based on direct sequencing of the PCR-amplified products of the 400 nucleotides coding for the amino terminus of the nucleoprotein. Phylogenetic relationships were analysed after bootstrap resampling using the maximum parsimony and the neighbour-joining methods. Analyses of both the nucleotide and amino acid sequences placed these viruses in three separate clusters, namely genotype 4 (Duvenhage), genotype 5 (EBL1) and genotype 6 (EBL2). Evolutionary analysis of the nucleoprotein gene of EBL1 and EBL2 indicated low intrinsic heterogeneity mainly due to synonymous substitutions. In addition, both EBL1 and EBL2 evolved into at least two genetically distinguishable lineages (a and b) following geographical drifting. We can speculate that subsequently the lineages EBL1a and EBL1b were introduced into parts of northern Europe from two different geographical directions; EBL1b was probably introduced most recently and was from North Africa. Eptesicus serotinus appears to be the principal reservoir for EBL1 and Myotis dasycneme and M. daubentonii the reservoirs for EBL2.