Alternative matrices for cortisol measurement in fish

Plasma cortisol is the most commonly used indicator of stress in fish but, as the blood sampling procedure itself can be a source of stress, it would be helpful to measure cortisol using less invasive matrices. It is also necessary to find alternative matrices as stress indicators in dead fish in which blood sampling is impossible. In the present study, we investigated transport stress in three aquaculture species, European sea bass (Dicentrarchus labrax L.), common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss Walbaum), by cortisol determination (radioimmunoassay) in plasma and other matrices (skin mucus, gut content, lateral muscle and caudal fin). Cortisol significantly increased after transport in all species and matrices, except in the sea bass gut content, where it remained unchanged. The three species responded to transport stress by producing different cortisol levels. In conclusion, the significant correlation found between plasma cortisol and most of the other matrices opens up the possibility of using them to evaluate stress in fish: mucus sampling is a less invasive method than blood sampling, and in addition to muscle and fin sampling, it can be used in postmortem fish.     

Evaluation of result variability with a commercial Johne's disease enzyme-linked immunosorbent assay kit and repeat testing of samples.

Two hundred one serum samples from individual dairy cows with a range of results on initial testing with a commercial Johne's disease enzyme-linked immunosorbent assay (ELISA) kit were repeat tested 5 times in each of 2 laboratories with kits produced by the same manufacturer. The results for the samples with all 10 replicates showed that the values for individual samples often had a coefficient of variation greater than 20%. As expected, the standard deviation for the results increased as the average value increased and the coefficient of variation was greater in samples with low mean values. The different lots of the commercial ELISA kit used in this study had a significant effect on both the optical density and the calculated sample to positive (S/P) ratio for test replicates. Based on the variability detected in S/P ratios of replicate samples, application of a single cutoff point to interpret individual test results as positive or negative for antibodies to Mycobacterium avium subspecies paratuberculosis could result in inconsistent classification of animals as positive or negative for Johne's disease. Such inconsistency in test interpretation leads to frustration in large animal veterinarians or producers trying to make management decisions based on individual test results. Instead of dichotomizing the test results as positive or negative based on a single cutoff value, reporting numerical values and supplying a classification scheme that includes a suspect category reflecting the uncertainty inherent in the test is recommended to provide more reliable result interpretation.     

Production of Haploid Sugar Beet (Beta vulgaris L.) by Culturing Unpollinated Ovules

The culture of unpollinated ovules is shown to be a suitable system for the production of haploid sugar beet (Beta vulgaris L.). The yield of haploids depended upon the genotype and varied between 0 and 13 % with a mean of 1.0 %. Haploid plants could be produced from approximately 50 % of all genotypes examined. The majority of the haploids isolated (about 90%) maintained the haploid genome level during the in vitro culture and propagation; 10% of the haploid clones showed a spontaneous doubling to the diploid genome level.     

Effects of type of added salt and ionic strength on physicochemical and functional properties of casein isolates produced by electroacidification

A procedure developed for soybean protein precipitation which was based on electrodialysis was tested for the production of acid casein from reconstituted skim milk. In a previous paper, the performance of bipolar membrane electroacidification (BMEA) was evaluated under different conditions of ionic strength (micro(added) = 0, 0.25, 0.5, or 1.0 M) and added salt (CaCl(2), NaCl, or KCl) (1). The aim of this study, which is the complement of the work on evaluation of BMEA performance, was to evaluate the functionality of the protein isolates produced by BMEA and to compare the BMEA isolates to commercial isolates and an isolate produced by chemical acidification. It was not possible to show differences between the functional properties of isolates produced by BMEA, except at 1 M CaCl(2) micro(added), due to the variability of the isolates. However, the results showed that it is possible to obtain isolates similar to commercial isolates and that the addition of salt during the process does not induce variations in functional properties. From results on mineral concentrations, it appeared that the addition of monovalent cations did not influence the retention of monovalent or divalent cations in the BMEA isolates, while addition of divalent cations (CaCl(2)) influenced the retention of magnesium. According to previous results on evaluation of BMEA performances under different conditions of ionic strength and added salt, the difference observed for the BMEA isolate produced at 1.0 M CaCl(2) was confirmed.     

Patterns of amphibian diversity in Brazilian Amazonia: conservation implications

A literature survey was conducted to determine the amphibian diversity and distribution in Brazilian Amazonia. Patterns of endemisms and similarity of fauna between localities were also addressed. Twenty-eight inventories were found for the region, the majority localized in areas with easier access by road or river. A minimum of 163 amphibian species was recorded for Brazilian Amazonia. Although many species are endemic to the Amazonian lowlands as an entity, the patterns of species uniqueness among sites suggested low endemic distribution within the lowlands of the Amazon Basin. The mean similarity between localities varied from low to intermediate (mean=0.40), indicating that the Brazilian Amazonia is characterized by distinctive assemblages of amphibians throughout its extension. Localities further apart had lower similarity. No threatened species were recorded. These results contribute to determine priority areas for new inventories and establishment of conservation units. We suggest that areas next to the Amazon deforestation frontier should be prioritized for new studies due to the high rate of alteration and potential loss of species. Additionally, studies on amphibian population dynamics are few in Brazilian Amazonia and more of them should be emphasized to help to draw a better picture of the status of amphibians in this region.     

Aquatic Gastropods as Mercury Indicatorsin the Pantanal of Poconé Region (Mato Grosso, Brasil)

Gold mining is the principal polluting activity in themunicipality of Poconé at the northern limit ofthe Pantanal of Mato Grosso, Brasil and ischaracterized by the inadequate use of mercury in thegold extraction process. A way to contribute to theassessment of the environmental impact of mercuryrelease in the Pantanal is to make use of bioaccumulation. Thus, determinations of total mercuryin 188 Gastropods of three different species were madein seven different sampling sites during the dry andwet periods. Increase of mercury levels in the snailswas restricted to the gold mining area and adjacentsedimentation areas. The largest mercuryconcentrations were found at the Tanque dos Padressite, reaching 2.04 g g^-1 in individuals ofPomacea scalaris. In the other sampling sites,molluscs collected in the Araras/Piuval Bay complex,a mercury retention area, showed the largest mercuryconcentration, reaching up to 1.12 g g^-1.     

Temperature responses of NO and N2O emissions from boreal organic soil

Both NO and N₂O are produced in soil microbial processes and have importance in atmospheric physics and chemistry. In recent years several studies have shown that N₂O emissions from organic soils can be high at low temperatures. However, the effects of low temperature on NO emissions from soil are unknown. We studied in laboratory conditions, using undisturbed soil cores, the emissions of NO and N₂O from organic soils at various temperatures, with an emphasis on processes and emissions during soil freezing and thawing periods. We found no soil freezing- or thawing-related emission maxima for NO, while the N₂O emissions were higher both during soil freezing and thawing periods. The results suggest that different factors are involved in the regulation of NO and N₂O emissions at low temperatures.     

A predator unmasked: life cycle of Bdellovibrio bacteriovorus from a genomic perspective

Predatory bacteria remain molecularly enigmatic, despite their presence in many microbial communities. Here we report the complete genome of Bdellovibrio bacteriovorus HD100, a predatory Gram-negative bacterium that invades and consumes other Gram-negative bacteria. Its surprisingly large genome shows no evidence of recent gene transfer from its prey. A plethora of paralogous gene families coding for enzymes, such as hydrolases and transporters, are used throughout the life cycle of B. bacteriovorus for prey entry, prey killing, and the uptake of complex molecules.     

The BRCT domain is a phospho-protein binding domain

The carboxyl-terminal domain (BRCT) of the Breast Cancer Gene 1 (BRCA1) protein is an evolutionarily conserved module that exists in a large number of proteins from prokaryotes to eukaryotes. Although most BRCT domain-containing proteins participate in DNA-damage checkpoint or DNA-repair pathways, or both, the function of the BRCT domain is not fully understood. We show that the BRCA1 BRCT domain directly interacts with phosphorylated BRCA1-Associated Carboxyl-terminal Helicase (BACH1). This specific interaction between BRCA1 and phosphorylated BACH1 is cell cycle regulated and is required for DNA damage-induced checkpoint control during the transition from G2 to M phase of the cell cycle. Further, we show that two other BRCT domains interact with their respective physiological partners in a phosphorylation-dependent manner. Thirteen additional BRCT domains also preferentially bind phospho-peptides rather than nonphosphorylated control peptides. These data imply that the BRCT domain is a phospho-protein binding domain involved in cell cycle control.     

The chemistry of sexual deception in an orchid-wasp pollination system

The "sexually deceptive" orchid Chiloglottis trapeziformis attracts males of its pollinator species, the thynnine wasp Neozeleboria cryptoides, by emitting a unique volatile compound, 2-ethyl-5-propylcyclohexan-1,3-dione, which is also produced by female wasps as a male-attracting sex pheromone.