Effect of gonadotropin-releasing hormone on fertility in repeat-breeder California dairy cows

To assess the potential benefit to fertility from gonadotropin-releasing hormone (GnRH) administration to third service cows managed in typical California dairy systems, 963 cows were enlisted from 14 dairies served by 6 veterinary practices. The cows were randomly assigned to receive either GnRH (100 mug) or placebo at the time of the third artificial insemination. Fertility data were entered onto a proprietary microcomputer program common to all six practices, and collated independently by a third party. For the duration of the trial (1 yr), GnRH and placebo-treated cows had 43.2 and 39.3% conception rates, respectively (P=0.35). When treatments administered in summer months (July, August, September) were excluded, conception rates were 48.1 and 41.0%, respectively (P<0.1). The conception rates of cows treated with GnRH in August tended to be lower than those of placebo-treated cows (95% logarithmic confidence intervals of odds ratio = -1.139, 0.377). Between-herd variation in benefit from GnRH was evident, with two dairies showing no benefit, one dairy showing a negative effect, and four showing a range of effects from lightly beneficial to significantly beneficial. First-lactation cows did not benefit at any time from GnRH treatment. The data suggest that GnRH administered to third-service dairy cows under California conditions may result in increased conception rates in non-summer months, but that other unidentified variables may have important influence on the outcome of such treatment.     

The oxidation of proline by mitochondrial preparations

The oxidation by mitochondria of various rat tissues of proline, pyrroline-5-carboxylate (P5C) and a number of aldehydes has been studied and ADP/O ratios determined for liver mitochondria. High oxidative activity for proline and P5C was found only in the liver and kidney. During the oxidation by liver and kidney mitochondria of proline and P5C; glutamate, ammonia, aspartate and some ornithine accumulated, thus suggesting that proline may normally be converted to ornithine by mitochondria. The oxidation of P5C (glutamic acid semialdehyde) by a mitochondrial dehydrogenase may be the same enzyme that oxidizes succinic acid semi-aldehyde but different from that oxidizing acetaldehyde.     

The importance of arginine in evolution

The special chemistry and metabolism of arginine has been considered in relation to the evolution of metabolic and structural features of animals. Arginine and compounds derived from it act in muscle as a major reserve of ATP and as a regulatory sink for phosphate. The metabolism of arginine in less complex animals has been extended to produce urea, firstly as an osmotic regulator and subsequently as a means for terrestrial animals to excrete surplus nitrogen. The ornithine component of arginine is metabolised to form important polyamines and also proline. It is also argued that the change from phosphoarginine to phosphocreatine was a permissive step in the development of the vertebrates which are rich in connective tissue.     

Discovery of novel benzylidene-1,3-thiazolidine-2,4-diones as potent and selective inhibitors of the PIM-1, PIM-2, and PIM-3 protein kinases

Novel substituted benzylidene-1,3-thiazolidine-2,4-diones (TZDs) have been identified as potent and highly selective inhibitors of the PIM kinases. The synthesis and SAR of these compounds are described, along with X-ray crystallographic, anti-proliferative, and selectivity data.     

Identifying the neural circuitry of alcohol craving and relapse vulnerability

With no further intervention, relapse rates in detoxified alcoholics are high and usually exceed 80% of all detoxified patients. It has been suggested that stress and exposure to priming doses of alcohol and to alcohol-associated stimuli (cues) contribute to the relapse risk after detoxification. This article focuses on neuronal correlates of cue responses in detoxified alcoholics. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) can be associated with alcohol craving and functional brain activation in neuronal systems that process attentional relevant stimuli, reward expectancy and experience. Increased functional brain activation elicited by such alcohol-associated cues predicted an increased relapse risk, whereas high brain activity elicited by affectively positive stimuli may represent a protective factor and was correlated with a decreased prospective relapse risk. These findings are discussed with respect to psychotherapeutic and pharmacological treatment options.     

The Carnivorous Pale Pitcher Plant Harbors Diverse,Distinct, and Time-Dependent Bacterial Communities

The ability of American carnivorous pitcher plants (Sarracenia) to digest insect prey is facilitated by microbial associations. Knowledge of the details surrounding this interaction has been limited by our capability to characterize bacterial diversity in this system. To describe microbial diversity within and between pitchers of one species, Sarracenia alata, and to explore how these communities change over time as pitchers accumulate and digest insect prey, we collected and analyzed environmental sequence tag (454 pyrosequencing) and genomic fingerprint (automated ribosomal intergenic spacer analysis and terminal restriction fragment length polymorphism) data. Microbial richness associated with pitcher plant fluid is high; more than 1,000 unique phylogroups were identified across at least seven phyla and 50 families. We documented an increase in bacterial diversity and abundance with time and observed repeated changes in bacterial community composition. Pitchers from different plants harbored significantly more similar bacterial communities at a given time point than communities coming from the same genetic host over time. The microbial communities in pitcher plant fluid also differ significantly from those present in the surrounding soil. These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction.Characterization of the phyllosphere is fundamental to our understanding of the ecology and evolution of plant populations and plant diversity and their interactions with other organisms (46, 64, 66). The carnivorous pitcher plant genus Sarracenia is an obvious system to address basic questions in plant-microbe interaction because each pitcher (a modified leaf) of the plant contains a microcosm composed of larval insects, fungi, algae, rotifers, nematodes, and bacteria that, together, ultimately break down nutrients from insect prey for the plant (1, 10, 20, 28, 37). Each pitcher represents a naturally defined and discrete community with a finite volume and a discrete life span (each leaf lasts only one season). Several investigations have explored species interactions within Sarracenia pitchers (13, 20, 34, 54), and competition, predation and dispersal frequency appear to be important drivers of community composition in the system (1, 20, 43, 44). Studies involving community patterns on a larger scale within pitchers, however, are few, and the processes that produce these patterns remain unknown (33).     

Geographical variation in temporal and spatial vocalization patterns of male harbour seals in the mating season

In the aquatically mating harbour seal, Phoca vitulina, oestrous females show marked differences in spatial and temporal distribution between geographical areas. This suggests that the males' display behaviour may also vary between areas. We recorded male vocalizations in two areas, the Moray Firth and Orkney, U.K. In the Moray Firth, females haul out on a few intertidal sandbars and travel along predictable routes to forage at sea. In Orkney, female haul out sites are much less influenced by tidal availability and females are much more dispersed. In the Moray Firth, males vocalized only during a short mating season, from 1 July to 12 August. Vocalizations varied significantly with the tide, the peak at high tide clearly coinciding with the period when most females were in the water. In contrast, vocalizations in Orkney were significantly related to both tidal and diel patterns. We suggest that the timing of male vocalizations reflects differences in female availability between sites. In the inner Moray Firth, vocalizations were heard throughout the females' range, whereas vocalizations in Orkney were heard only in two discrete areas. However, at both sites the density of vocalizing males was highest in narrow channels and/or along predictable female travel routes. Therefore, males clearly adapt their temporal and spatial behaviour patterns to variations in female distribution and density. These results suggest that male mating strategies in aquatically mating pinnipeds are more variable than was previously envisaged. Copyright 1999 The Association for the Study of Animal Behaviour.     

A limited survey of aflatoxins and fumonisins in retail maizebased products in the UK using immunoassay detection

A total of 27 maize-based products destined for human consumption were collected from retail outlets within the city of Glasgow in the UK and were analysed for the presence of aflatoxins using immunoaftinity column chromatography with fluorescence detection and for fumonisins by competitive ELISA. Aflatoxins were detected at a trace level below 4 in eight (30%) of the 27 samples tested, no sample contained aflatoxins at a high level although one sample of sweetcorn did contain aflatoxins at a level of 5-10 Fumonisins were detected in eight (30%) of the samples at levels from 1 to 8mgkg^-1 and a further eight samples contained fumonisin at a level below 1 mgkg^-1 but above the detectable level. The highest concentration of fumonisins was found in a sample of fine corn meal at 8-12mgkg^-1.