Parallel increases in rates of fatty acid synthesis and in pyruvate dehydrogenase activity in isolated rat hepatocytes incubated with insulin

The effect of insulin on the activity of pyruvate dehydrogenase is studied in isolated hepatocytes from fed rats. Insulin increases the ‘initial’ activity of pyruvate dehydrogenase by 30% without modifying the total activity of the enzyme. The maximal increase is reached 3 min after addition of the hormone and is dose-dependent. Insulin also increases the rate of fatty acid synthesis.     

Responses of pony mares to the agent of contagious equine metritis 1977.

Reproduction of contagious equine metritis 1977 in Pony mares was achieved with cultures of an unclassified Gram-negative coccobacillus. Infected mares developed a vaginal discharge and associated inflammatory changes of the cervix and vagina. There was evidence of variation in pathogenicity between different strains of the organism. Although all infected mares made spontaneous clinical recoveries, the Gram-negative coccobacillus persisted in the genital tracts of a considerable proportion for a variable period after challenge. Recovery of the organism was not associated solely with the occurrence of oestrus. None of the mares has carried over infection into the following breeding season. There was no evidence of localization of the organism in the urinary tract. Cytological examination of smears of cervical and urethral swabs was of diagnostic value only during the clinical phase of the infection. A serological response was demonstrable in all mares that became infected after exposure to the Gram-negative coccobacillus. The complement-fixation test gave more specific and clear-cut results than either the agglutination or the antiglobulin test, with which there was a problem with non-specific reactions. The experimental findings indicate the value of the complement-fixation test for confirming recent cases of contagious equine metritis in the mare.     

A comparative analysis of the NMR relaxation times of two human colon cancer cell lines

Two human colon cancer cell lines grown in tissue culture were found to have significantly different Nuclear Magnetic Resonance (NMR) relaxation times of water protons in the fresh, intact state and after fragmentation into subcellular fractions. Differences in the protein composition of the subcellular fractions were also demonstrated by protein analysis and gel chromatography. In further studies, these cell lines may be useful to investigate the biochemical basis for the disparity in relaxation times of water protons between tissues which constitutes the basis for Magnetic Resonance Imaging (MRI) tissue contrast.     

Decades of dietary data demonstrate regional food web structures in the Southern Ocean

Understanding regional‐scale food web structure in the Southern Ocean is critical to informing fisheries management and assessments of climate change impacts on Southern Ocean ecosystems and ecosystem services. Historically, a large component of Southern Ocean ecosystem research has focused on Antarctic krill, which provide a short, highly efficient food chain, linking primary producers to higher trophic levels. Over the last 15 years, the presence of alternative energy pathways has been identified and hypotheses on their relative importance in different regions raised. Using the largest circumpolar dietary database ever compiled, we tested these hypotheses using an empirical circumpolar comparison of food webs across the four major regions/sectors of the Southern Ocean (defined as south of 40°S) within the austral summer period. We used network analyses and generalizations of taxonomic food web structure to confirm that while Antarctic krill are dominant as the mid‐trophic level for the Atlantic and East Pacific food webs (including the Scotia Arc and Western Antarctic Peninsula), mesopelagic fish and other krill species are dominant contributors to predator diets in the Indian and West Pacific regions (East Antarctica and the Ross Sea). We also highlight how tracking data and habitat modeling for mobile top predators in the Southern Ocean show that these species integrate food webs over large regional scales. Our study provides a quantitative assessment, based on field observations, of the degree of regional differentiation in Southern Ocean food webs and the relative importance of alternative energy pathways between regions.     

Medium-term organ culture for teleost fish retinae

Whole retinae from Midas cichlids Cichlasoma citrinellum were maintained successfully in superfusion culture for 21 days post-removal and continued to exhibit normal light- and circadian-driven cone movements.     

A reevaluation of rabbit anti-allotype antibody for the presence of cross-reactive idiotypes. I. A species-specific idiotype on rabbit anti-a1 antibody is recognized by guinea pig anti-IdX antibody

Rabbit reagents previously thought to display specificity for a cross-reactive idiotype on anti-VHa allotype antibody from all tested rabbits have recently been shown to be contaminated with an induced (latent) molecule similar or identical to the original antigen (rabbit a1 or a2 allotype). In an attempt to circumvent this problem, we have immunized guinea pigs with rabbit anti-a1 allotype antibody to produce heterologous anti-idiotype antibody. The resulting guinea pig antibody (GP anti-R IdX) recognizes anti-a1 antibody from each of 17 immunized rabbits, and in four tested samples reacts with 22 to 100% of the molecules. Neither goat nor guinea pig anti-a1 reacts with the guinea pig anti-R IdX antibody, even though the goat, guinea pig, and rabbit anti-a1 Ab all recognize a similar set of a1 determinants. The reaction between IdX-bearing rabbit anti-a1 and guinea pig anti-R IdX is inhibited by the original antigen (a1 IgG), demonstrating that the IdX is at or near the antigen combining site of anti-a1 antibody. Immunoelectron microscopy of immune complexes supports this conclusion and demonstrates that the reactive site on the GP anti-R IdX is at or near its antigen combining site.