Seeking the true time: Exploring otolith chemistry as an age-determination tool

Fish otoliths' chronometric properties make them useful for age and growth rate estimation in fisheries management. For the Eastern Baltic Sea cod stock (Gadus morhua), unclear seasonal growth zones in otoliths have resulted in unreliable age and growth information. Here, a new age estimation method based on seasonal patterns in trace elemental otolith incorporation was tested for the first time and compared with the traditional method of visually counting growth zones, using otoliths from the Baltic and North seas. Various trace elemental ratios, linked to fish metabolic activity (higher in summer) or external environment (migration to colder, deeper habitats with higher salinity in winter), were tested for age estimation based on assessing their seasonal variations in concentration. Mg:Ca and P:Ca, both proxies for growth and metabolic activity, showed greatest seasonality and therefore have the best potential to be used as chemical clocks. Otolith image readability was significantly lower in the Baltic than in the North Sea. The chemical (novel) method had an overall greater precision and percentage agreement among readers (11.2%, 74.0%) than the visual (traditional) method (23.1%, 51.0%). Visual readers generally selected more highly contrasting zones as annuli whereas the chemical readers identified brighter regions within the first two annuli and darker zones thereafter. Visual estimates produced significantly higher, more variable ages than did the chemical ones. Based on the analyses in our study, we suggest that otolith microchemistry is a promising alternative ageing method for fish populations difficult to age, such as the Eastern Baltic cod.     

ISS-An Electronic Syndromic Surveillance System for Infectious Disease in Rural China

Background

syndromic surveillance system has great advantages in promoting the early detection of epidemics and reducing the necessities of disease confirmation, and it is especially effective for surveillance in resource poor settings. However, most current syndromic surveillance systems are established in developed countries, and there are very few reports on the development of an electronic syndromic surveillance system in resource-constrained settings.

Objective

this study describes the design and pilot implementation of an electronic surveillance system (ISS) for the early detection of infectious disease epidemics in rural China, complementing the conventional case report surveillance system.

Methods

ISS was developed based on an existing platform ‘Crisis Information Sharing Platform’ (CRISP), combining with modern communication and GIS technology. ISS has four interconnected functions: 1) work group and communication group; 2) data source and collection; 3) data visualization; and 4) outbreak detection and alerting.

Results

As of Jan. 31^st 2012, ISS has been installed and pilot tested for six months in four counties in rural China. 95 health facilities, 14 pharmacies and 24 primary schools participated in the pilot study, entering respectively 74256, 79701, and 2330 daily records into the central database. More than 90% of surveillance units at the study sites are able to send daily information into the system. In the paper, we also presented the pilot data from health facilities in the two counties, which showed the ISS system had the potential to identify the change of disease patterns at the community level.

Conclusions

The ISS platform may facilitate the early detection of infectious disease epidemic as it provides near real-time syndromic data collection, interactive visualization, and automated aberration detection. However, several constraints and challenges were encountered during the pilot implementation of ISS in rural China.     

Adaptive divergence in body size overrides the effects of plasticity across natural habitats in the brown trout

The evolution of life-history traits is characterized by trade-offs between different selection pressures, as well as plasticity across environmental conditions. Yet, studies on local adaptation are often performed under artificial conditions, leaving two issues unexplored: (i) how consistent are laboratory inferred local adaptations under natural conditions and (ii) how much phenotypic variation is attributed to phenotypic plasticity and to adaptive evolution, respectively, across environmental conditions? We reared fish from six locally adapted (domesticated and wild) populations of anadromous brown trout (Salmo trutta) in one semi-natural and three natural streams and recorded a key life-history trait (body size at the end of first growth season). We found that population-specific reaction norms were close to parallel across different streams and Q_ST was similar – and larger than F_ST – within all streams, indicating a consistency of local adaptation in body size across natural environments. The amount of variation explained by population origin exceeded the variation across stream environments, indicating that genetic effects derived from adaptive processes have a stronger effect on phenotypic variation than plasticity induced by environmental conditions. These results suggest that plasticity does not “swamp” the phenotypic variation, and that selection may thus be efficient in generating genetic change.     

Cloning,functional expression,biochemical characterization,and structural analysis of a haloalkane dehalogenase from <Emphasis Type="Italic">Plesiocystis pacifica</Emphasis> SIR-1

A haloalkane dehalogenase (DppA) from Plesiocystis pacifica SIR-1 was identified by sequence comparison in the NCBI database, cloned, functionally expressed in Escherichia coli, purified, and biochemically characterized. The three-dimensional (3D) structure was determined by X-ray crystallography and has been refined at 1.95 Å resolution to an R-factor of 21.93%. The enzyme is composed of an α/β-hydrolase fold and a cap domain and the overall fold is similar to other known haloalkane dehalogenases. Active site residues were identified as Asp123, His278, and Asp249 and Trp124 and Trp163 as halide-stabilizing residues. DppA, like DhlA from Xanthobacter autotrophicus GJ10, is a member of the haloalkane dehalogenase subfamily HLD-I. As a consequence, these enzymes have in common the relative position of their catalytic residues within the structure and also show some similarities in the substrate specificity. The enzyme shows high preference for 1-bromobutane and does not accept chlorinated alkanes, halo acids, or halo alcohols. It is a monomeric protein with a molecular mass of 32.6 kDa and exhibits maximum activity between 33 and 37°C with a pH optimum between pH 8 and 9. The K_m and k_cat values for 1-bromobutane were 24.0 mM and 8.08 s^?1. Furthermore, from the 3D-structure of DppA, it was found that the enzyme possesses a large and open active site pocket. Docking experiments were performed to explain the experimentally determined substrate preferences.     

Seasonal variation in fecundity,egg case viability,gestation, and neonate size for little skates, <Emphasis Type="Italic">Leucoraja erinacea</Emphasis>, in the Gulf of Maine

Landings of the little skate, Leucoraja erinacea, within the territorial waters of the United States are currently regulated by a federal fishery management plan (FMP). For a FMP to be effective, thorough knowledge of a species’ reproductive biology is essential. Currently, little information exists on annual fecundity, egg case viability, gestation length, and neonate total length, for the little skate in the Gulf of Maine. To study these reproductive parameters, mature skates and egg cases were housed in fiberglass tanks with an open seawater system that provided natural, seasonal fluctuations in water temperature. Egg case deposition was highest during summer months with a seasonal peak in June. Of the 324 egg cases laid by seven females (c. 46 eggs per year, per female), 74.1% were viable. Gestation lengths ranged from 22 to 54 weeks throughout the four seasons. Egg cases laid in the fall had the longest gestation times (44.9 weeks, ± 0.13 weeks) and those laid in the spring had the shortest gestation times (24.5 weeks, ± 0.21 weeks). Total lengths of neonates from spring oviposition were statistically the longest (10.74 ± 0.05 cm) when compared to neonates from other seasons; however, egg viability was statistically the lowest for spring when compared seasonally.     

A hierarchical whole-body modeling approach elucidates the link between in Vitro insulin signaling and in Vivo glucose homeostasis

Type 2 diabetes is a metabolic disease that profoundly affects energy homeostasis. The disease involves failure at several levels and subsystems and is characterized by insulin resistance in target cells and tissues (i.e. by impaired intracellular insulin signaling). We have previously used an iterative experimental-theoretical approach to unravel the early insulin signaling events in primary human adipocytes. That study, like most insulin signaling studies, is based on in vitro experimental examination of cells, and the in vivo relevance of such studies for human beings has not been systematically examined. Herein, we develop a hierarchical model of the adipose tissue, which links intracellular insulin control of glucose transport in human primary adipocytes with whole-body glucose homeostasis. An iterative approach between experiments and minimal modeling allowed us to conclude that it is not possible to scale up the experimentally determined glucose uptake by the isolated adipocytes to match the glucose uptake profile of the adipose tissue in vivo. However, a model that additionally includes insulin effects on blood flow in the adipose tissue and GLUT4 translocation due to cell handling can explain all data, but neither of these additions is sufficient independently. We also extend the minimal model to include hierarchical dynamic links to more detailed models (both to our own models and to those by others), which act as submodules that can be turned on or off. The resulting multilevel hierarchical model can merge detailed results on different subsystems into a coherent understanding of whole-body glucose homeostasis. This hierarchical modeling can potentially create bridges between other experimental model systems and the in vivo human situation and offers a framework for systematic evaluation of the physiological relevance of in vitro obtained molecular/cellular experimental data.     

Parasite diversity as an indicator of environmental change? An example from tropical grouper (Epinephelus fuscoguttatus) mariculture in Indonesia

Fish parasites are used to monitor long-term change in finfish grouper mariculture in Indonesia. A total of 210 Epinephelus fuscoguttatus were sampled in six consecutive years between 2003/04 and 2008/09 and examined for parasites. The fish were obtained from floating net cages of a commercially run mariculture facility that opened in 2001. The fauna was species rich, consisting of ten ecto- and 18 endoparasite species. The ectoparasite diversity and composition was relatively stable, with the monogeneans Pseudorhabdosynochus spp. (83-100% prevalence, Berger-Parker Index of 0·82-0·97) being the predominant taxon. Tetraphyllidean larvae Scolex pleuronectis and the nematodes Terranova sp. and Raphidascaris sp. 1 were highly abundant in 2003/04-2005/06 (max. prevalence S. pleuronectis 40%, Terranova sp. 57%, Raphidascaris sp. 1 100%), and drastically reduced until 2008/09. These parasites together with the prevalence of Trichodina spp., ecto-/endoparasite ratio and endoparasite diversity illustrate a significant change in holding conditions over the years. This can be either referred to a definite change in management methods such as feed use and fish treatment, or a possible transition of a relatively undisturbed marine environment into a more affected habitat. By visualizing all parameters within a single diagram, we demonstrate that fish parasites are useful bioindicators to monitor long-term change in Indonesian grouper mariculture. This also indicates that groupers can be used to monitor environmental change in the wild. Further taxonomic and systematic efforts in less sampled regions significantly contributes to this new application, supporting fish culture and environmental impact monitoring also in other tropical marine habitats.     

Contrasting demographic history and population structure in Capsella rubella and Capsella grandiflora, two closely related species with different mating systems

Both mating system and population history can have large impacts on genetic diversity and population structure. Here, we use multilocus sequence data to investigate how these factors impact two closely related Brassicaceae species: the selfing Capsella rubella and the outcrossing C. grandiflora. To do this, we have sequenced 16 loci in approximately 70 individuals from 7 populations of each species. Patterns of population structure differ strongly between the two species. In C. grandiflora, we observe an isolation-by-distance pattern and identify three clearly delineated genetic groups. In C. rubella, where we estimate the selfing rate to be 0.90-0.94, the pattern is less clear with some sampling populations forming separate genetic clusters while others are highly mixed. The two species also have divergent histories. Our analysis gives support for a bottleneck approximately 73 kya (20-139 kya) in C. rubella, which most likely represents speciation from C. grandiflora. In C. grandiflora, there is moderate support for the standard neutral model in 2 of 3 genetic clusters, while the third cluster and the total data set show evidence of expansion. It is clear that mating system has an impact on these two species, for example affecting the level of genetic variation and the genetic structure. However, our results also clearly show that a combination of past and present processes, some of which are not affected by mating system, is needed to explain the differences between C. rubella and C. grandiflora.     

Swedish Experience Using Environmental Accounts Data for Integrated Product Policy Issues

This article quantifies and ranks the environmental pressure caused by different product groups consumed in Sweden. This is done using information from economic and environmental statistics. An analysis for the year 1998 is performed for approximately 50 product groups using input-output analysis. This type of analysis has some major advantages for integrated product policy (IPP) purposes: the underlying data are regularly updated, the data systems are being harmonized by international standards, and the connection between environmental goals and IPP goals can be investigated. This article summarizes two Swedish reports, one for the Producer Responsibility Committee and one for the Swedish Environmental Protection Agency. The results show that the volume of consumption is an important factor in environmental pressure from products as well as impact intensities. The most important product categories for private consumption are petroleum products, electricity, construction, and food and beverages, as well as transport. Possibilities of building indicators for IPP are also discussed.