Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea) across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ15N values of bulk skin, with distinct “low δ15N” and “high δ15N” groups. δ15N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ15N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation efforts in light of this species’ imminent risk of extinction in the Pacific

Analysis of the unexplored features of rrs (16S rDNA) of the Genus Clostridium

<p>Abstract</p> <p>Background</p> <p>Bacterial taxonomy and phylogeny based on <it>rrs </it>(16S rDNA) sequencing is being vigorously pursued. In fact, it has been stated that novel biological findings are driven by comparison and integration of massive data sets. In spite of a large reservoir of <it>rrs </it>sequencing data of 1,237,963 entries, this analysis invariably needs supplementation with other genes. The need is to divide the genetic variability within a taxa or genus at their <it>rrs </it>phylogenetic boundaries and to discover those fundamental features, which will enable the bacteria to naturally fall within them. Within the large bacterial community, <it>Clostridium </it>represents a large genus of around 110 species of significant biotechnological and medical importance. Certain <it>Clostridium </it>strains produce some of the deadliest toxins, which cause heavy economic losses. We have targeted this genus because of its high genetic diversity, which does not allow accurate typing with the available molecular methods.</p> <p>Results</p> <p>Seven hundred sixty five <it>rrs </it>sequences (> 1200 nucleotides, nts) belonging to 110 <it>Clostridium </it>species were analyzed. On the basis of 404 <it>rrs </it>sequences belonging to 15 <it>Clostridium </it>species, we have developed species specific: (i) phylogenetic framework, (ii) signatures (30 nts) and (iii) <it>in silico </it>restriction enzyme (14 Type II REs) digestion patterns. These tools allowed: (i) species level identification of 95 <it>Clostridium </it>sp. which are presently classified up to genus level, (ii) identification of 84 novel <it>Clostridium </it>spp. and (iii) potential reduction in the number of <it>Clostridium </it>species represented by small populations.</p> <p>Conclusions</p> <p>This integrated approach is quite sensitive and can be easily extended as a molecular tool for diagnostic and taxonomic identification of any microbe of importance to food industries and health services. Since rapid and correct identification allows quicker diagnosis and consequently treatment as well, it is likely to lead to reduction in economic losses and mortality rates.</p

Is the timing of spawning in sparid fishes a response to sea temperature regimes?

Published spawning seasons of sparid fish were investigated to determine if there were consistent patterns that could be related to large-scale physical variability, and whether these relationships were species-specific or characteristic of higher taxonomic groupings. For individual species, genera and the family Sparidae as a whole, there was a consistent pattern; spawning at lower latitudes was concentrated close to the month of lowest sea surface temperature, while spawning at higher latitudes was more variable with greater deviations from the month of minimum sea surface temperature. The distribution of sparids may be limited by a lack of tolerance of one or more early life-history stage to high water temperatures, so targeting spawning to the coolest part of the year could be a tactic allowing maximum penetration into warmer waters. Such a link between the physiology of early life-history stages and timing of spawning could have direct consequences for patterns of distributions over a number of taxonomic scales. If there are similar constraints on the reproduction of other species, even minor increases in water temperature due to global warming that may be within the tolerance of adults, may impose constraints on the timing of spawning, with flow-on effects for both species and whole ecosystems

Total and specific dietary polyphenol intakes and 6-year anthropometric changes in a middle-aged general population cohort

International audienceBACKGROUND:Dietary polyphenols are suggested anti-obesogenic agents. Prospective evidence in general populations of an association between polyphenol intakes and anthropometry is lacking.OBJECTIVE:To assess the associations between dietary polyphenol intakes and changes in body mass index (BMI) and waist circumference (WC) over a 6-year period.METHODS:Individual intakes of 264 different polyphenols (mg/day) were estimated using the Phenol-Explorer database and the mean of 6-17 24-h dietary records collected in 1994-1996. BMI in kg/m2 and WC in cm were measured in 1995-1996, 1998-1999 and 2001-2002. Linear mixed effect models allowed for the assessment of longitudinal associations between energy adjusted quartiles of total polyphenol intake as well as intake of 15 polyphenol classes and changes of these respective polyphenol classes in anthropometry over the 6 years of follow-up. Adjustment variables included sex, age, socio-economic status, lifestyle, dietary intakes and health status.RESULTS:Participants in the highest quartile of intake of flavanones (BMI change: -0.28 (-0.43; -0.13), P=0.009), flavones (BMI change: -0.29 (-0.44; -0.14), P=0.008), and lignans (BMI change: -0.28 (-1.63; -0.09), P=0.01) experienced a less notable increase in BMI over time compared to their counterparts in the bottom quartile of intake of the respective polyphenol classes. Participants in the highest quartile of intake of flavanones (WC change: -1.39 (-2.02; -0.92), P=0.001), flavones (WC change: -1.57 (-2.32; -0.92), P=0.001), hydroxycinnamic acids (WC change: -1.27 (-1.92; -0.63), P=0.01), lignans (WC change: -1.16 (-1.80; -0.51), P=0.006) and total polyphenol intake (WC change: -1.39 (-2.05; -0.74), P=0.001) experienced a less notable increase in WC over time compared to their counterparts in the bottom quartile of intake of the respective polyphenols.CONCLUSIONS:Dietary polyphenol intakes may help reduce weight gain over time in the general population. This could have important public health implications because moderate increases in BMI and WC over time have been shown to increase disease risk