Effect of a cold stimulus on the synthesis of uncoupling protein in brown adipose tissue of rats and newborn rabbits

Rats are known to respond to a cold stimulus by increasing the activity and amount of the uncoupling protein in brown adipose tissue. A 48 h cold stimulus was found to increase the synthesis of uncoupling protein 3.g-fold in 4–5 week old rats whereas no change was observed with newborn rabbits. The lack of response in the latter case may reflect a difference between rabbits and rats or that synthesis is already maximal in newborn rabbits.     

Mitochondrial DNA of the basidiomycete Polyporus ciliatus

Summary Mitochondrial (mt) DNA of the white rot fungus Polyporus ciliatus was isolated and characterized. As a result of detailed restriction enzyme analysis, a physical map was established showing that this circular DNA has a molecular weight of 88.2 kb. By heterologous cross hybridization the sites of three mt genes were recognized. By nonselective cloning of mt DNA fragments in Saccharomyces cerevisiae, an autonomously replicating sequence (ars) was identified which has potential application in the development of a prokaryotic/eukaryotic shuttle vector.     

Immunoelectron microscopic studies on the localization of peptidoglycan peptide subunit pentapeptides in bacterial cell walls

The peptide subunit pentapeptide H-L-Ala-D-Glu(L-Lys-D-Ala-D-Ala-OH)-NH₂ of peptidoglycan was localized in the cell walls of several Gram-positive bacteria employing the indirect immunoferritin technique. Specific antibodies to the D-alanyl-D-alanine moiety of non-crosslinked peptide subunit pentapeptide were raised in rabbits by immunization with synthetic immunogen albumin-(CH₂CO-Gly-L-Ala-L-Ala-D-Ala-D-Ala-OH)₃₉. Specificity of these antibodies for the peptide subunit pentapeptide and not for the peptide subunit tetrapeptide was corroborated in a Farr-type radio-active hapten binding assay. Specificity of labelling with ferritin was established by immunoelectron microscopic controls, and by the excellent correlation between specific labelling of cells with ferritin and the particular peptidoglycan primary structure of bacterial strains investigated. Cells of Lactobacillus gasseri, Streptococcus pyogenes and Staphylococcus aureus revealing non-crosslinked peptide subunit pentapeptides in their peptidoglycans could specifically be labelled. Lactobacillus acidophilus and Bacillus subtilis, on the contrary, missing such pentapeptides, failed in labelling.The implication of this method to possibly localize the points of attack of penicillin or cycloserine is discussed.Abbreviations used meso-A₂pm meso-diaminopimelic acid - DSM Deutsche Sammlung für Mikroorganismen, Göttingen, FRG This paper is dedicated to Professor Gerhart Drews on the occasion of his 60th birthday     

The case for a polyphyletic origin of mitochondria: Morphological and molecular comparisons

The comparative morphology and pigmentation of protists suggest that those with tubular mitochondrial cristae belong to a different lineage than those with lamellar cristae and that the evolutionary divergence might have been very early. We propose that the difference in cristal morphology is the result of separate origins of the mitochondria from endosymbionts related to the Rhodospirillaceae (purple nonsulfur bacteria) but differing in the morphology of their internal membranes. Comparisons of the cytochromes c of protists and the Rhodospirillaceae and of 16s rRNA T1 oligonucleotide catalogs in the Rhodospirillaceae do not contradict, and in fact provide support for, the idea. More extensive evidence may be lacking simply because cytochromes c have been studied in very few protists with tubular mitochondrial cristae.     

Response of muscle protein turnover to insulin after acute exercise and training.

To determine whether the enhanced insulin-sensitivity of glucose metabolism in muscle after acute exercise also extends to protein metabolism, untrained and exercise-trained rats were subjected to an acute bout of exercise, and the responses of protein synthesis and degradation to insulin were measured in epitrochlearis muscles in vitro. Acute exercise of both untrained and trained rats decreased protein synthesis in muscle in the absence or presence of insulin, but protein degradation was not altered. Exercise training alone had no effect on protein synthesis or degradation in muscle in the absence or presence of insulin. Acute exercise or training alone enhanced the sensitivities of both protein synthesis and degradation to insulin, but the enhanced insulin-sensitivities from training alone were not additive to those after acute exercise. These results indicate that: a decrease in protein synthesis is the primary change in muscle protein turnover after acute exercise and is not altered by prior exercise training, and the enhanced insulin-sensitivities of metabolism of both glucose and protein after either acute exercise or training suggest post-binding receptor events.     

Immunocytochemistry of magnocellular neurons of supraoptic and paraventricular nuclei of normal and Brattleboro rats with vasopressin anti-idiotype antibody

Summary A vasopressin anti-idiotype antibody was generated by immunization with purified IgG of a primary vasopressin antiserum. The anti-idiotype antibody immunostained neurons in the supraoptic and paraventricular nuclei of the hypothalamus of normal and Brattleboro rats. The distribution of immunostained perikarya in these hypothalamic nuclei together with the staining of fibers in median eminence and neural lobe was similar to that observed in normal rats with anti-vasopressin and suggests strongly that vasopressinergic neurons are being stained. Absorption studies with vasopressin and a vasopressin-binding receptor protein further indicate that a receptor associated with vasopressinergic neurons is recognized by the anti-idiotype antibody.Supported by NIH grants ES03239, NS18626 and NSF grant BNS-8310914. D.T.P. is the receipient of RCDA award NS00869     

Thermotoga maritima sp. nov. represents a new genus of unique extremely thermophilic eubacteria growing up to 90°C

A novel type of bacterium has been isolated from various geothermally heated locales on the sea floor. The organisms are strictly anaerobic, rod-shaped, fermentative, extremely thermophilic and grow between 55 and 90°C with an optimum of around 80°C. Cells show a unique sheath-like structure and monotrichous flagellation. By 16S rRNA sequencing they clearly belong to the eubacteria, although no close relationship to any known group could be detected. The majority of their lipids appear to be unique in structure among the eubacteria. Isolate MSB8 is described as Thermotoga maritima, representing the new genus Thermotoga.Dedicated to Otto Kandler on the occasion of his 65th birthday Present addresses: University of South Dakota, Vermillion, USA; University of Illinois, Urbana, USA; Universität für Bodenkultur, Wien, Austria     

Pyrococcus furiosus sp. nov. represents a novel genus of marine heterotrophic archaebacteria growing optimally at 100°C

Ten strains representing a novel genus of marine thermophilic archaebacteria growing at between 70 and 103°C with an optimal growth temperature of 100°C and a doubling time of only 37 min were isolated from geothermally heated marine sediments at the beach of Porto di Levante, Vulcano, Italy. The organisms are spherical-shaped, 0.8 to 2.5 m in width and exhibit monopolar polytrichous flagellation. They are strictly anaerobic heterotrophs, growing on starch, maltose, peptone and complex organic substrates. Only CO₂ and H₂ could be detected as metabolic products, the latter being inhibitory to growth at high concentrations. Hydrogen inhibition can be prevented by the addition of S^o, whereupon H₂S is formed in addition, most likely as the result of a detoxification reaction. The GC-content of the DNA of isolate Vc 1 is 38 mol%. The new genus is named Pyrococcus, the fireball. Type species and strain is Pyrococcus furiosus Vc 1 (DSM 3638).