Surface mucous as a source of genomic DNA from Atlantic billfishes (Istiophoridae) and swordfish (Xiphiidae)

Procedures for sampling genomic DNA from live billfishes involve manual restraint and tissue excision that can be difficult to carry out and may produce stresses that affect fish survival. We examined the collection of surface mucous as a less invasive alternative method for sourcing genomic DNA by comparing it to autologous muscle tissue samples from Atlantic blue marlin (Makaira nigricans), white marlin (Tetrapturus albidus), sailfish (Istiophorus platypterus), and swordfish (Xiphias gladius). Purified DNA from mucous was comparable to muscle and was suitable for conventional polymerase chain reaction, random amplified polymorphic DNA analysis, and mitochondrial and nuclear locus sequencing. The nondestructive and less invasive characteristics of surface mucous collection may promote increased survival of released specimens and may be advantageous for other marine fish genetic studies, particularly those involving large live specimens destined for release

Development and Characterization of 11 Novel Microsatellite Loci for the Roundscale Spearfish Tetrapturus georgii and Their Cross-Species Amplification Among Other Istiophorid Species

Eleven novel polymorphic microsatellite loci were developed and characterized for the recently validated roundscale spearfish Tetrapturus georgii. Characterization of these markers, based on 35 roundscale spearfish from the western North Atlantic, revealed two to 21 alleles per locus with an average expected heterozygosity (HE) of 0·09–0·94, and all loci conformed to Hardy–Weinberg expectations. Cross-amplification of these 11 loci against all other eight known istiophorid species indicates promising prospects for the utility of these markers for istiophorids in general

A Fish Habitat Classification Model for the Upper and Middle Sections of the Bay of Quinte, Lake Ontario

A fish habitat classification model was developed and applied to the upper and middle sections of the Bay of Quinte, Lake Ontario. Available habitat inventories were assembled in a GIS database, bringing bathymetric, shoreline, substrate, and vegetation data together in a series of layers. The classification model was developed in four steps. In the first step, the Defensible Methods (DM) model developed by Minns et al. (2000) was used to estimate suitability values in all habitat patches for a set of nine fish groups each with three life stages. The fish groups were formed from the assemblage of fish species present in the Bay of Quinte by combining them according to thermal and vegetation preferences, and combinations of size and age-at-maturity. Different methods of combining the 27 suitability indices were examined to allow designation of each unique habitat patch to low, medium or high suitability categories for fish. The K-means clustering technique was selected for classifying habitat patches into three suitability categories, thereby exploiting natural breaks in the cumulative distributions of suitability values and maintaining consistency with underlying habitat features. In the second step, the spatially rare habitats for each fish group by life stage combination were used to identify habitat patches that are important for particular fish groups and life stages but which had been classified as medium or low suitability in the first classification step. Criteria for recognizing rarity were used to reassign habitat patches rated low or medium in step one to the high class. In the third step, local expert knowledge of important fish habitats gathered from anglers and fishers were used to develop an expert classification. This expert mapping of important fishing areas was compared with that obtained via suitability and rarity ratings and then, in step four, used to upgrade some areas from low or medium to high. The final habitat classification model is a mixture of suitability, rarity and expert ratings. The habitat suitability class assignments obtained in step one were not changed appreciably by steps two and three. The combined suitability-rarity ratings showed good agreement with the local expert ratings. Important fishing areas either overlapped suitable areas or were close by where fisher access would be restricted by depth or vegetation density. The final habitat classification for the Bay of Quinte provides a context for both conservation and restoration efforts. Periodic updating of the classification system will be needed as conditions change, e.g., as a result of climate change or as the effects of the zebra mussel invasion on macrophytes and substrates mature, or as data on other habitat elements becomes available, e.g., seasonal and spatially thermal habitat maps. Further effort is needed to understand the procedures used by government agencies at different levels to integrate the knowledge embodied in habitat maps into on-going fisheries and fish habitat management

Development and Characterization of Thirteen Microsatellite Markers for the Longbill Spearfish (Tetrapturus pfluegeri)

The longbill spearfish (Tetrapturus pfluegeri; Istiophoridae) is an epipelagic billfish species broadly distributed in the Atlantic Ocean and exploited by multinational fisheries. No data exist on the population structure or genetic diversity of this apex predator, despite a strong need for this information to inform international conservation and management efforts. Thirteen microsatellite loci, comprising mostly tri- and tetra-nucleotide repeats, were isolated and characterized for this species by genotyping individuals (n = 29–42) obtained from western North and South Atlantic fisheries. The average number of alleles ranged from 3 to 16 and the expected heterozygosity ranged from 0.35 to 0.86. This suite of markers provides the first population genetic nuclear resources for the longbill spearfish, allowing initiation of studies for assessing the population structure and demography of this poorly understood species

Scaling and universality in turbulent convection

Anomalous correlation functions of the temperature field in two-dimensional turbulent convection are shown to be universal with respect to the choice of external sources. Moreover, they are equal to the anomalous correlations of the concentration field of a passive tracer advected by the convective flow itself. The statistics of velocity differences is found to be universal, self-similar and close to Gaussian. These results point to the conclusion that temperature intermittency in two-dimensional turbulent convection may be traced back to the existence of statistically preserved structures, as it is in passive scalar turbulence.Comment: 4 pages, 6 figure

Passive scalar turbulence in high dimensions

Exploiting a Lagrangian strategy we present a numerical study for both perturbative and nonperturbative regions of the Kraichnan advection model. The major result is the numerical assessment of the first-order $1/d$-expansion by M. Chertkov, G. Falkovich, I. Kolokolov and V. Lebedev ({\it Phys. Rev. E}, {\bf 52}, 4924 (1995)) for the fourth-order scalar structure function in the limit of high dimensions $d$'s. %Two values of the velocity scaling exponent $\xi$ have been considered: %$\xi=0.8$ and $\xi=0.6$. In the first case, the perturbative regime %takes place at $d\sim 30$, while in the second at $d\sim 25$, %in agreement with the fact that the relevant small parameter %of the theory is $\propto 1/(d (2-\xi))$. In addition to the perturbative results, the behavior of the anomaly for the sixth-order structure functions {\it vs} the velocity scaling exponent, $\xi$, is investigated and the resulting behavior discussed.Comment: 4 pages, Latex, 4 figure

Comparative Population Genetics and Evolutionary History of Two Commonly Misidentified Billfishes of Management and Conservation Concern

Background: Misidentifications between exploited species may lead to inaccuracies in population assessments, with potentially irreversible conservation ramifications if overexploitation of either species is occurring. A notable showcase is provided by the realization that the roundscale spearfish (Tetrapturus georgii), a recently validated species, has been historically misidentified as the morphologically very similar and severely overfished white marlin (Kajikia albida) (IUCN listing: Vulnerable). In effect, no information exists on the population status and evolutionary history of the enigmatic roundscale spearfish, a large, highly vagile and broadly distributed pelagic species. We provide the first population genetic evaluation of the roundscale spearfish, utilizing nuclear microsatellite and mitochondrial DNA sequence markers. Furthermore, we re-evaluated existing white marlin mitochondrial genetic data and present our findings in a comparative context to the roundscale spearfish. Results: Microsatellite and mitochondrial (control region) DNA markers provided mixed evidence for roundscale spearfish population differentiation between the western north and south Atlantic regions, depending on marker-statistical analysis combination used. Mitochondrial DNA analyses provided strong signals of historical population growth for both white marlin and roundscale spearfish, but higher genetic diversity and effective female population size (1.5-1.9X) for white marlin. Conclusions: The equivocal indications of roundscale spearfish population structure, combined with a smaller effective female population size compared to the white marlin, already a species of concern, suggests that a species-specific and precautionary management strategy recognizing two management units is prudent for this newly validated billfish

The Behavioural and Genetic Mating System of the Sand Tiger Shark, Carcharias taurus, an Intrauterine Cannibal

Sand tiger sharks (Carcharias taurus) have an unusual mode of reproduction, whereby the first embryos in each of the paired uteri to reach a certain size (‘hatchlings’) consume all of their smaller siblings during gestation (‘embryonic cannibalism’ or EC). If females commonly mate with multiple males (‘behavioural polyandry’) then litters could initially have multiple sires. It is possible, however, that EC could exclude of all but one of these sires from producing offspring thus influencing the species genetic mating system (‘genetic monogamy’). Here, we use microsatellite DNA profiling of mothers and their litters (n = 15, from two to nine embryos per litter) to quantify the frequency of behavioural and genetic polyandry in this system. We conservatively estimate that nine of the females we examined (60%) were behaviourally polyandrous. The genetic mating system was characterized by assessing sibling relationships between hatchlings and revealed only 40 per cent genetic polyandry (i.e. hatchlings were full siblings in 60% of litters). The discrepancy stemmed from three females that were initially fertilized by multiple males but only produced hatchlings with one of them. This reveals that males can be excluded even after fertilizing ova and that some instances of genetic monogamy in this population arise from the reduction in litter size by EC. More research is needed on how cryptic post-copulatory and post-zygotic processes contribute to determining paternity and bridging the behavioural and genetic mating systems of viviparous species

Helicobacter pylori-derived neutrophil-activating protein increases the lifespan of monocytes and neutrophils

P>An invariable feature of Helicobacter pylori-infected gastric mucosa is the persistent infiltration of inflammatory cells. The neutrophil-activating protein (HP-NAP) has a pivotal role in triggering and orchestrating the phlogistic process associated with H. pylori infection. Aim of this study was to address whether HP-NAP might further contribute to the inflammation by increasing the lifespan of inflammatory cells. We report that HP-NAP is able to prolong the lifespan of monocytes, in parallel with the induction of the anti-apoptotic proteins A1, Mcl-1, Bcl-2 and Bcl-X(L). This effect does not result from a direct action on the apoptotic machinery, but rather it requires the release of endogenous pro-survival factors, such as interleukin-1 beta, which probably acts in synergy with other unidentified mediators. We also report that HP-NAP promotes the survival of Ficoll-purified neutrophils in a monocyte-dependent fashion: indeed, mononuclear cell depletion of Ficoll-purified neutrophils completely abolished the pro-survival effect by HP-NAP. In conclusion, our data reinforce the notion that HP-NAP has a pivotal role in sustaining a prolonged activation of myeloid cells