Scaling of connectivity in marine populations

Defining the scale of connectivity, or exchange, among marine populations and determining the factors driving this exchange are pivotal to our understanding of the population dynamics, genetic structure, and biogeography of many coastal species. Using a high-resolution biophysical model for the Caribbean region, we report that typical larval dispersal distances of ecologically relevant magnitudes are on the scale of only 10 to 100 kilometers for a variety of reef fish species. We also show the importance of the early onset of active larval movement mediating the dispersal potential. In addition to self-recruitment, larval import from outside the local area is required to sustain most populations, although these population subsidies are very limited in particular systems. The results reveal distinct regions of population isolation based on larval dispersal that also correspond to genetic and morphological clines observed across a range of marine organisms.     

Identification of the DDAH2 Protein in Pig Reproductive Tract Mucus: A Putative Oestrus Detection Marker

Precisely detecting oestrus is important for artificial insemination. The aims of this study were to identify oestrus‐specific sow mucus proteins to determine the optimal time for artificial insemination. The proestrous‐ and oestrous‐stage mucus proteins were purified and analysed with proteomic tools such as two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization–time‐of‐flight analyses. Among the differentially expressed proteins, the dimethylarginine dimethylaminohydrolase 2 (DDAH2) protein showed a 3.6‐fold increase during the proestrous stage compared to that during the oestrous stage. A western immunoblot study revealed that two of three sow mucus samples clearly showed negative anti‐DDAH2 antibody activity during the oestrous stage. This study demonstrated that the pig DDAH2 mucus protein exists during the proestrous stage, but not during the oestrous stage, suggesting that mucus DDAH2 could be useful as an oestrus detection marker.     

Comparing farmers and breeders rankings in varietal selection for low-input environments: A case study of rainfed rice in eastern India

A number of breeding institutions developed a project to assess importance of participatory plant breeding approaches for rainfed rice improvement in eastern India. The results of the first two years of participatory varietal selection are reported here. The objective was to evaluate the respective effects of participation of farmers in varietal evaluation and decentralization of varietal testing from breeding stations to farmers' fields on varietal ranking. Fields representing various hydrological situations were chosen in two to three villages at four rainfed lowland sites and one upland site. Sets of 15 to 25 varieties were tested both in farmers' fields and on-station in 1997 and 1998 and ranked by both farmers and breeders. The effect of participation was judged by comparing the rankings attributed by farmers and breeders to a given set of material in a given trial. The effect of decentralization was determined through comparisons between individual breeders' rankings across trials. Farmers' rankings were not randomly allocated, but agreement within the farmers' group was not always very strong. Except at one site, concordance among breeders' ranking was high, but, because of the limited number of breeders involved, it was seldom significant. In about two-thirds of the trials, there was a good agreement between farmers' and breeders' mean rankings. The consensus was particularly strong when severe constraints induced contrasting behavior in the genotypes. The decentralization effect appeared to be moderate, but variations due to a breeder effect were recorded. The part of genotype by environment interactions for grain yield due to location within one site and year was evaluated through various methods, showing more effect of G × E interactions at some sites than at others. Crossover interactions inducing changes in ranks represented a limited part of the yearly G × E interactions at all sites. Both farmer participation and decentralization of varietal testing in farmers' field would help in best matching the varieties to the needs, although their combined contribution would be more useful in some sites than in others. This revised version was published online in August 2006 with corrections to the Cover Date.     

Microbial removal of lead from solid media and soil

We have isolated a Pseudomonas aeruginosa strain designated CHL004 which is able to remove lead from solidified media and soil. The process for testing removal was generally the same for all experiments. A piece of sterile filter paper was placed on the surface of a plate containing solidified media and lead carbonate or lead contaminated soil and incubated at 29 °C for 30 days. Lead was removed from yeast malt plates but generally not from R2A plates. Dextrose was shown to be a critical component in the YM; without it almost no lead was removed. Sucrose, maltose and lactose could not be substituted for the dextrose although these carbon sources allowed for survival and growth of the isolate. In order to study the initial kinetics of lead uptake, lead nitrate was used in an aqueous environment. The rate of uptake of lead nitrate by CHL004 was very rapid initially then decreased greatly. Sodium azide treated cells did not remove lead. The removal of lead from an urban soil was affected by the pH of the soil. The pH of the soil in YM was 6.9 and 3.3% of the total lead in the soil was removed. When the pH was adjusted to a pH of 5, 8% of the total lead was removed but at a pH of 6, 6.4% was removed.     

Methods for Equine Preantral Follicles Isolation: Quantitative Aspects

The aim of this study was to test the use of mechanical and mechanical‐enzymatic methods, saline solution (SS), and PBS solution for the manipulation and isolation of mare ovarian preantral follicles (PAFs). The ovaries were subjected to mechanical isolation (mixer) alone or in association with enzymatic digestion (collagenase). Incubation times of 10 and 20 min were employed. In the first group, 4.1 ± 4.9 PAFs were harvested with the mechanical‐enzymatic method vs 71.1 ± 19.2 with the mechanical procedure, showing a significant difference between methods; using SS and PBS, these numbers were 35.7 ± 34.3 and 39.6 ± 39.6, respectively, with no significant difference between solutions. In the second group, there was significant difference between methods, with 7.1 ± 10.6 follicles harvested with the mechanical‐enzymatic method vs 63.2 ± 22.9 with the mechanical procedure; using SS and PBS, means were 35.5 ± 36.4 and 34.9 ± 31.1, respectively. The mechanical method proved more effective than the mechanical‐enzymatic approach. Both SS and PBS can be used as a media for equine PAFs preparation.     

Root growth following defruiting improves peach tree water status

Summary

Tree growth and water status throughout the growing season and after fruit removal were studied in container-grown peach trees. Trees with fruit (F) and defruited (DF) trees were sampled destructively at bud break (8 March), 1 month after fruit removal (3 June), at harvest (6 August), and before leaf fall (15 October) to determine the mass of leaves, current season shoots, branches, trunk, and the entire root system. Tree water status was determined from the mid-day stem water potential (SWP) the day before each sampling date. Root growth in DF trees was greater than that observed in F trees, while the above-ground biomass was similar in DF and F trees. DF trees therefore had lower leaf:root biomass ratios than F trees throughout the fruit growing season. Environmental factors did not fully explain the seasonal variations in SWP, but there was a significant correlation between leaf:root biomass ratios and SWP. Reductions in leaf:root biomass ratios were accompanied by increases in SWP and, ultimately, DF trees had higher SWP values than F trees in mid-Summer. Improvements in tree water status following fruit removal can be explained, in part, by additional root growth.     

Another gene affecting fruit and stem color in squash, Cucurbita pepo

Of the 13 genes described as affecting fruit color in Cucurbita pepo, one, D (Dark stem), also markedly affects stem color. The D allele confers dark stems and dark intermediate-age fruits, is dominant to the d allele for light stems and fruits, and epistatic to two recessive genes conferring light fruit coloration, l-1 and l-2. However, a gene for light fruit coloration, W (Weak fruit color), is epistatic to D in the fruits. We observed variation for stem color in a scallop squash cultivar having light-colored fruits, some plants having dark stems and others light stems. Two true-breeding inbreds of this cultivar, one having dark stems and the other light stems, were developed and, when these inbreds were crossed, the progeny had light stems. In order to elucidate the genetic basis of the dominant light-stem characteristic, these two inbreds were crossed with two near-isogenic tester lines, one of genotype D/D l-1/l-1 l-2/l-2 and the other of genotype d/d l-1/l-1 l-2/l-2. Also, the dominant light stem and light fruit color were introgressed into a third near-isogenic line of genotype D/D l-1/l-1 l-2/l-2, resulting in two new near-isogenic lines, and these lines were then intercrossed. The results showed that the variation in stem color of the scallop squash cultivar derives from segregation of alleles at the W locus, with a newly designated top-dominant allele, W ^S , conferring both, light stems and light fruits. This allele may be genetically unstable and sub-vital.     

Recherche des colorants naturels et artificiels dans les aliments à l'aide de la chromatographie sur couche mince

Résumé La recherche des colorants dans les aliments est de première importance, car non seulement les colorants modifient l'aspect des substances comestibles, mais bien souvent ils interviennent dans les effets physiologiques d'une façon bienfaisante (action vitaminique, antiseptique) ou malfaisante (action toxique). Il faut d'ailleurs distinguer les colorants normaux des colorants ajoutés aux matières alimentaires. Ces additifs pouvant être constitués par des colorants naturels ou artificiels, seuls certains d'entre eux sont autorisés par la loi, d'où l'intérêt de la caractérisation des colorants au point de vue des falsifications et de la santé publique.Dans des milieux aussi complexes que les aliments, la recherche des colorants est longue et difficile, d'autant plus qu'il s'agit la plupart du temps de mélange de principes de teintes variées; la chromatographie, et en particulier la chromatographie sur couche mince, est venue apporter une heureuse solution à la résolution de ce problème compliqué. Cependant elle est rarement applicable directement à l'analyse des aliments, il faut au préalable préparer une liqueur extractive amenant une certaine purification des pigments: fractionnement par solvants, adsorption sur floche de laine, sur ruban polyfibres, sur échangeurs d'ions, formation de complexes insolubles dans l'eau ou solubles dans les solvants organiques, etc.La chromatographie sur couche mince elle-même s'effectue dans des conditions différentes suivant qu'il s'agisse de substances liposolubles (caroténoïdes, quinones) ou de principes hydrosolubles (flavonoïdes, anthocyanes, dérivés sulfurés, etc); dans le premier cas seront utilisées des plaques activées avec des solvants anhydres. Les solvants seront également différents suivant qu'il s'agit de colorants acides ou de colorants basiques. La révélation est souvent inutile, les substances à caractériser étant naturellement colorées; cependant il est utile d'observer les changements de teintes à divers pH et par formation de complexes métalliques. Enfin, pour une meilleure caractérisation, il est prudent d'opérer comparativement avec des substances étalons.

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Summary The detection of dyes in foods is of primary importance, since not only do the dyes modify the aspect of edible substances, but very often intervene in the physiological effects in a beneficial (vitaminic or antiseptic action) or a harmful (toxic effects) way. One must distinguish normal colouring matter from dyes added to foods. As these additives include natural colouring matters and artificial dyes, only a few of them are authorized by law, hence the importance of the characterization of the dyes from the standpoint of adulterations and public health.In medium as complex as are the foods the detection of dyes is long and difficult in as much as most of the times it concerns mixtures of compounds of various colourings; chromatography, and more especially thin-layer chromatography, has brought a happy solution to this complicated problem. However, it is seldom applicable directly to the analysis of foods, the preliminary preparation of an extractive liquor bringing a certain purification of the pigments: solvents fractionation, adsorption on soft wool or polyfiber, on ion exchangers, formation of water-insoluble, (or soluble in organic solvents) complexes.This layer chromatography in itself is carried out in different conditions depending on whether one has to do with fat soluble substances (carotenoïds, quinones), or water soluble ones (flavonoïds, anthocyans, sulphurid derivatives). In the first case plates activated by anhydrous solvents will be used. Solvents will also differ depending on whether the dyes are acid or basic. Development is usually useless, as the substances to be characterized are coloured naturally; it is useless to observe alterations of tints at various values of pH, and by the formation of metal complexes. To conclude, for a better characterization it will be safer to operate comparatively with standard substances.

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Zusammenfassung Der Nachweis von Farbstoffen in den Lebensmitteln ist von größter Bedeutung, da dieselben nicht nur das Aussehen verändern, sondern oft auch auf die physiologischen Wirkungen einen günstigen (vitaminisierende oder antiseptische Wirkung) oder nachteiligen (giftige Wirkung) Einfluß haben. Es ist übrigens zwischen normalen und den Nahrungsmitteln zugesetzten Farbstoffen zu unterscheiden. Diese Fremdstoffe können natürliche oder künstliche Farbstoffe sein. Von ihnen sind nur einige durch Gesetz zugelassen. Hier liegt die große Bedeutung der Farbstoffidentifizierung zum Nachweis der Fälschungen und zum Schutz der öffentlichen Gesundheit.Auf einem so komplexen Gebiet wie der Lebensmittel, ist der Farbstoffnachweis langwierig und schwierig, um so mehr da es sich zumeist um Gemische verschiedener Farbprinzipien handelt. Zur Lösung dieser komplizierten Probleme trägt die Chromatographie und insbesondere die DC entscheidend bei. Letztere kann jedoch selten direkt zur Lebensmittelanalyse angewandt werden. Als Vorbereitung muß eine Extraktionsflüssigkeit, die zu einer Pigmentreinigung führt, hergestellt werden: Trennung durch Lösungsmittel, Adsorbierung auf Wollbausch, auf Mehrfachstreifen, auf Ionenaustauscher, Bildung unlöslicher Komplexe in Wasser oder löslicher Komplexe in organischen Lösungsmitteln, usw. — Die DC selbst wird unter verschiedenen Bedingungen durchgeführt, wenn es sich um fettlösliche (Carotinoide, Chinone) oder wasserlösliche (Flavonoide, Anthocyane, Schwefelabkömmlinge, usw.) Stoffe handelt. Im ersten Fall benutzt man mit wasserfreien Lösungsmitteln aktivierte Plättchen. Auch die Lösungsmittel sind verschieden und zwar ob es sich um saure oder basische Farbstoffe handelt. Meist bedarf es keiner Entwicklung, da die Stoffe natürliche Färbung aufweisen. Es ist jedoch wichtig, die Farbänderungen bei verschiedenem pH und bei der Bildung von Metallkomplexen zu beobachten. Schließlich ist es ratsam für eine gute Identifizierung, Vergleichsversuche mit Standard-Stoffen durchzuführen.