Fine-Scale Population Structure of Blue Whale Wintering Aggregations in the Gulf of California

Population differentiation in environments without well-defined geographical barriers represents a challenge for wildlife management. Based on a comprehensive database of individual sighting records (1988–2009) of blue whales from the winter/calving Gulf of California, we assessed the fine-scale genetic and spatial structure of the population using individual-based approaches. Skin samples of 187 individuals were analyzed for nine microsatellite loci. A single population with no divergence among years and months and no isolation by distance (Rxy = 0.1–0.001, p>0.05) were found. We ran two Bayesian clustering methods using Structure and Geneland softwares in two different ways: 1) a general analysis including all individuals in which a single cluster was identified with both softwares; 2) a specific analysis of females only in which two main clusters (Loreto Bay and northern areas, and San Jose-La Paz Bay area) were revealed by Geneland program. This study provides information indicating that blue whales wintering in the Gulf of California are part of a single population unit and showed a fine-scale structure among females, possibly associated with their high site fidelity, particularly when attending calves. It is likely that the loss of genetic variation is minimized by male mediated gene flow, which may reduce the genetic drift effect. Opportunities for kin selection may also influence calf survival and, in consequence, have a positive impact on population demography in this small and endangered population.     

Interaction between the ADH1C polymorphism and maternal alcohol intake in the risk of nonsyndromic oral clefts: an evaluation of the contribution of child and maternal genotypes

BACKGROUND: Maternal alcohol consumption has been associated with an increased risk of nonsyndromic oral clefts in some studies. Study of gene-environment interaction may provide insight into the reasons for their discrepancies observed. We focused on a polymorphism of the ADH1C gene (third gene of the class I alcohol dehydrogenase family), involved in the metabolism of ethanol and other alcohols. METHODS: Data come from a French case-control study (1998-2001), which tested the association between maternal alcohol consumption during the first trimester of pregnancy and the risk of nonsyndromic oral clefts (240 cases, 236 controls). A case-parent study design looked at the association with an ADH1C polymorphism (Ile349Val site) and potential gene-environment interaction effects. A log-linear model was used to distinguish the direct effect of the child's genotype from the maternally mediated effects. RESULTS: An increased risk of nonsyndromic oral clefts was observed for women who reported drinking alcohol during the first trimester, compared with women who did not. The mutated ADH1C allele carried by the child seemed to have a protective effect against the risk of oral clefts (RRone copy, 0.71; 95% confidence interval [CI], 0.50-1.02; RRtwo copies, 0.63; 95% CI, 0.3-1.3). The maternal genotype played a less important role than the child's, and its action remains unclear. No significant evidence of interaction effects between the ADH1C genotype and maternal alcohol consumption was observed. CONCLUSIONS: Because the ADH1C gene is involved in the metabolic pathways of many alcohols, we propose several hypotheses about the causal pathway, including ethanol oxidation activity and, more probably, retinol oxidation.     

Community-Based Control of the Brown Dog Tick in a Region with High Rates of Rocky Mountain Spotted Fever, 2012–2013

Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a significant public health risk on American Indian reservations in eastern Arizona. During 2003–2012, more than 250 RMSF cases and 19 deaths were documented among Arizona''s American Indian population. The high case fatality rate makes community-level interventions aimed at rapid and sustained reduction of ticks urgent. Beginning in 2012, a two year pilot integrated tick prevention campaign called the RMSF Rodeo was launched in a ∼600-home tribal community with high rates of RMSF. During year one, long-acting tick collars were placed on all dogs in the community, environmental acaricides were applied to yards monthly, and animal care practices such as spay and neuter and proper tethering procedures were encouraged. Tick levels, indicated by visible inspection of dogs, tick traps and homeowner reports were used to monitor tick presence and evaluate the efficacy of interventions throughout the project. By the end of year one, <1% of dogs in the RMSF Rodeo community had visible tick infestations five months after the project was started, compared to 64% of dogs in Non-Rodeo communities, and environmental tick levels were reduced below detectable levels. The second year of the project focused on use of the long-acting collar alone and achieved sustained tick control with fewer than 3% of dogs in the RMSF Rodeo community with visible tick infestations by the end of the second year. Homeowner reports of tick activity in the domestic and peridomestic setting showed similar decreases in tick activity compared to the non-project communities. Expansion of this successful project to other areas with Rhipicephalus-transmitted RMSF has the potential to reduce brown dog tick infestations and save human lives.     

Phosphatidylcholine deficiency upregulates enzymes of triacylglycerol metabolism in CHO cells

We studied the regulation of triacylglycerol (TAG) metabolism by phosphatidylcholine (PC) in CHO MT58 cells, which are deficient in PC synthesis because of a temperature-sensitive CTP:phosphocholine cytidylyltransferase. At the permissive growth temperature (34 degrees C), these cells contained 49% less TAG and 30% less PC than wild-type CHO K1 cells. Treatment with dipalmitoylphosphatidylcholine normalized both the PC and TAG levels. Despite low TAG levels, the incorporation of [14C]oleate into TAG was increased in CHO MT58 cells. The in vitro de novo synthesis of TAG and the activity of diacylglycerol acyltransferase were 90% and 34% higher, respectively. Two other key enzyme activities in TAG synthesis, acyl-CoA synthetase and mitochondrial glycerol-3-phosphate acyltransferase (GPAT), increased by 48% and 2-fold, respectively, and mitochondrial GPAT mRNA increased by approximately 4-fold. Additionally, TAG hydrolysis was accelerated in CHO MT58 cells, and in vitro lipolytic activity increased by 68%. These studies suggest that a homeostatic mechanism increases TAG synthesis and recycling in response to PC deficiency. TAG recycling produces diacylglycerol and fatty acids that can be substrates for de novo PC synthesis and for lysophosphatidylcholine (lysoPC) acylation. In CHO MT58 cells, in which de novo PC synthesis is blocked, lysoPC acylation with fatty acid originating from TAG may represent the main pathway for generating PC.     

Polyunsaturated fatty acid biosynthesis from [1-14C]20:3 n-6 acid in rat cultured Sertoli cells. Linoleic acid effect

Primary culture is a suitable system to study lipid metabolism and polyunsaturated fatty acid biosynthesis. Sertoli cell-enriched preparations were used to determine the fatty acid composition after 5 and 7 days in culture (serum free) as well as the uptake and metabolism of [1-14C]eicosa-8,11,14-trienoic acid. The addition of unlabeled linoleic acid (0.2 and 2.0 microg/ml) was also evaluated. Fatty acid methyl esters derived from cellular lipids were analyzed by gas liquid chromatography and radiochromatography. After 5 days in culture, cells had significantly less 18:2, 20:4, 22:5 and 24:5 and more 18:3, 20:3, 22:4 and 24:4 n-6 fatty acids than non-cultured cells. On day 7, an additional increment in 22:4 n-6 and a decrease in linoleic, gamma-linoleic and 24:4 n-6 fatty acids were observed. The presence of linoleic acid (low dose) produced a significant decrease in saturated and monounsaturated acids and an increase in 18:2, 20:4 and 22:5 n-6 fatty acids. At a high concentration almost all fatty acids belonging to 18:2 n-6 increased significantly. The drop in 20:4 n-6/20:3 n-6 ratio was considered as an indirect evidence of a Delta 5 desaturase activity depression. This assumption was corroborated by studying the transformation of [1-14C]eicosa-8,11,14-trienoic acid into 20:4, 22:4, 22:5, 24:4 and 24:5 n-6 fatty acids. We conclude that Sertoli cells after 7 days in culture evidenced changes in the fatty acid profile similar to those described under fat deprivation. The addition of linoleic acid reverted this pattern and indicated that the Delta 5 desaturase activity is a limiting step in the polyunsaturated fatty acid biosynthesis.     

Acoustic telemetry survey of the dusky grouper (Epinephelus marginatus) in the Marine Reserve of Cerbère-Banyuls: informations on the territoriality of this emblematic species

The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations (Epinephelus marginatus). Density survey and observation of the reproductive behavior of this species have been conducted there for the last 30 years. However, information on the behavior or habitat utilization for this species during winter time is limited. We conducted acoustic telemetry surveys from September 2005 to June 2006 in the Marine Reserve of Cerbère-Banyuls for a dusky grouper population. Six groupers were tagged and followed within the integral reserve and in the adjacent partial reserve. The results from the tracking of these individuals indicated that the largest dusky groupers are sedentary fishes with a high degree of site fidelity and a high sensitivity to variations of environmental conditions such as storms. This together with the life history characteristics of this species encourages the conservation and the protection of essential habitats of this species. Acoustic tracking coupled to the use of a fixed Kernel can be proposed to follow fish populations. To cite this article: J. Pastor et al., C. R. Biologies 332 (2009).     

Plasmodium falciparum and P. vivax gametocyte-specific exoantigens stimulate proliferation of TCR gammadelta+ lymphocytes

Immune modulation of Plasmodium vivax and P. falciparum gametocytes occurs over the course of erythrocytic infection. The response is linked to proliferative and inflammatory responses, which may be stimulated by stage-specific gametocyte proteins. Stage-specific exoantigens were purified from supernatants of P. falciparum and P. vivax gametocyte cultures, and either primary or secondary postinfection lymphocytes were stimulated for proliferation. Five of 25 exoantigens purified from P. falciparum gametocyte cultures and 6 of 28 exoantigens isolated from P. vivax were gametocyte stage specific. Metabolic labeling of soluble P. falciparum gametocyte proteins confirmed synthesis and secretion of 5 stage-specific exoantigens, with molecular masses of 118, 62, 52, 37, and 33 kDa. Purified gametocyte exoantigens within the range of 50 to 100 kDa stage-specifically stimulated proliferation of lymphocytes from postprimary P. falciparum infections, and from postprimary and secondary P. vivax infection patients with homologous purified exoantigens. T-cell receptor (TCR)gammadelta+, and CD3+ CD8+ and CD3+ CD4- CD8- T cells were specifically upregulated from P. falciparum primary- and P. vivax secondary-infection lymphocytes, respectively, using gametocyte stage-specific exoantigens. CD25+ was the major activation marker expressed by CD3+ and gammadelta T cells when stimulated with gametocyte exoantigens. None of the T cell markers was significantly upregulated using gametocyte stage-specific exoantigens with primary-infection P. vivax lymphocytes.     

First evidence of multiple paternity in the blue shark (Prionace glauca)

Multiple paternity (MP) is defined as the behaviour in which females successfully mate with multiple males leading to offspring from different sires within the same litter. MP seems to be frequent and an evolutionary advantage in elasmobranchs. Here the authors report for the first time the occurrence of MP in the cosmopolitan blue shark Prionace glauca L. The evidence, gathered via microsatellite genotyping of pregnant females and their embryos, suggests that MP is very frequent in this species. Knowledge of MP in P. glauca should help describe more precisely its reproductive biology and contribute to the management of its populations.     

Fatty acid profiles in hepatic membranes of rats with different levels of circulating estrogen and prolactin

Plasma and liver microsomal fatty acid patterns of female rats (Rattus norvegicus) with either low or high serum levels of prolactin (PRL) were studied. Hyperprolactinemia was achieved by grafting anterior pituitary glands or by estradiol administration. One group treated with estradiol also received bromocriptine to inhibit PRL secretion. Ovariectomized (OVX) rats showed a decrease in PRL levels as compared with intact animals (controls). Rats possessing high levels of circulating PRL showed a significant decrease of linoleic acid in the fatty acid pattern of total and polar liver microsomal lipids. High PRL levels in the presence of normal estrogen levels significantly increased arachidonic acid in the same group of lipids. The group of rats treated with estrogen evidenced a decrease in arachidonic acid and in the unsaturation index. From these results it is possible to infer a decrease in the activity of the desaturases. The changes observed in the estradiol-treated group were not modified by bromocriptine administration. OVX rats showed no changes when compared with controls. It is concluded that, while PRL decreases the microsomal unsaturation index, estrogen administration causes a decrease in poly-unsaturated fatty acid biosynthesis and that this effect is independent of PRL levels.