Transport properties of two extremely thermophilic species ofThermus

Thermus flavus and T. ruber grew optimally at 75 and 60 °C, respectively, but transport of monosaccharides (D-quinovose) and ammo acids (2-aminoisobutyric acid) had optima about 20 °C lower. Both transports were active, inhibited by 2,4-dinitrophenol but hardly at all by uranyl(2+) ions. Several transport systems are apparently involved with each class of compounds. Preincubation with glucose curtailed subsequent transport severely. Practical cessation of transport below 35 °C may be associated with the rather uniform composition of membrane lipids where iso- and anteiso-C₁₅ and C₁₇ acids are practically the only components.     

The effect of quaternary ammonium compounds and amine oxides on spores of bacillus cereus

The effect of 1-dodecylpiperidine 1-oxide and N,N’-bis(dodecyldimethyl)-1,2-ethane diammonium dibromide on the spores ofBacillus cereus. particularly their binding to intact spores and spores with reduced cystine bonds, was investigated. The Langmuir type of binding is involved in both cases. Both compounds decreased the thermoresistance of spores. DPNO decreased the fraction of non-germinating spores, the effect of the drug increasing with increasing concentration. This phenomenon was associated with a faster release of dipicolinic acid to the medium. Only microgermination proceeded in the presence of BDED and dipicolinic acid was released only in substantially lower amounts. Both compounds also influenced respiration.     

A lipopolysaccharide fromAspergillus flavus conidia

A lipopolysaccharide was isolated by extraction ofAspergillus flavus conidia with 45 % phenol at 68–70 °C. Quantitative analysis revealed 7 % nucleic acids, 5.5 % proteins, 46 % polysaccharides and 49 % lipids, of which 12 % were covalently bound. Glucose, mannose, galactose and fucose were detected as monosaccharide components of the polysaccharide moiety by gas chromatography; palmitic acid, stearic acid, oleic acid, linoleic acid and myristic acid were mainly present in the lipidic fraction. This material differs from the bacterial lipopolysaccharides, both in composition of the polysaccharide moiety and representation of fatty acids in the lipidic fraction.     

Relationship between the Number of Homoeologues, Chiasma Frequency and the Frequency of Telosome Pairing in Wheat

Pairing frequencies of a single telosome in groups of two, three, four, five and six equally related homoeologues were calculated for a range of values of c (the ratio of actual chiasma frequency to the total possible number of chiasmata, as described by Driscoll, Bielig and Darvey 1979). At low c values, the frequency of telosome pairing is little affected by the number of homoeologues. At high c values, the frequency is little affected by the number of homoeolgues if the number is even; if the number is odd, the frequency is dependent on the number of homoeologues and increases with increasing numbers of homoeologues. At intermediate c values, the pairing frequency is dependent on the number of homoeologues for both even and odd numbers of homoeologues.     

Contents,accumulation and release of energy in green,dead and decomposing plant materials in an upland grassland near Kameničky,Czechoslovakia

The energy content was studied in above-ground live plant material and in litter in a natural grassland ecosystem with dominantNardus stricto l., defined phytosociologically asPolygalo-Nardetum strictae Preising 1950 corr. Oberdorfer 1957, and in two of its fertilized variants in the course of 1975 to 1977. Based on the determined production characteristics and data on decomposition processes, the amounts of energy accumulated by the green parts of the stands and the amount of energy released during decomposition from the litter were calculated. Changes in the energy content of litter in different stages of decomposition were determined. With progressing decomposition the energy content per gram ash-free decomposing plant litter increases.     

Independent actions of gonadotropin releasing hormone upon cyclic GMP production and luteinizing hormone release

Gonadotropin releasing hormone (GnRH) and its potent analog [D-Ser(tBu)6]des-Gly10-GnRH N-ethylamide elevate pituitary cyclic GMP levels while stimulating gonadotropin release in cultured pituitary cells. Addition of mycophenolic acid to pituitary cell cultures decreased basal and GnRH-induced cGMP production to undetectable levels, but did not reduce basal or GnRH-stimulated luteinizing hormone (LH) release. Elevation of endogenous cGMP levels by sodium nitroprusside, or addition of cGMP or its potent derivatives, was also without effect on basal or GnRH-stimulated LH release. These findings demonstrate that the elevation of intracellular cGMP during GnRH action does not mediate the release of LH by pituitary cells.     

X-linked dominant inheritance of partial phosphorylase kinase deficiency in mice

A new mouse strain, the V strain, with a partial deficiency of phosphorylase kinase has been established. The deficiency is caused by an X-linked dominant gene (Phk ^c ). Muscle extracts of homozygous and heterozygous females and hemizygous males have about 25% of the activity found in extracts of normal (C3H/HeHan) mice. This dominant phosphorylase kinase deficiency of the new V strain is different from that of the I-strain mice with the X-linked recessive deficiency of skeletal muscle phosphorylase kinase. The muscle extracts of V-strain and normal mice contain the same phosphorylase phosphatase activity of about 1 U/mg. Heart and liver extracts from V mice contained about 50% and 66%, respectively, of the phosphorylase kinase activity compared to that found in the same organs from the normal mice. The glycogen content of the skeletal muscle of the V strain was normal, i.e., 0.9 mg/g. Phosphorylase kinase was purified from the skeletal muscle of the V strain by (a) hydrophobic chromatography on methylamine Sepharose, (b) ammonium sulfate precipitation, and (c) gel filtration of Sepharose 4B. The enzyme has a similar structure to the normal murine and rabbit skeletal muscle enzyme, except that the proportion of the subunits differs. The molar ratio of the subunits of the V strain mice is (+)::=0.54:1:1.169, in comparison with that of the rabbit (+)::=1.1:1.0:1.0 and that of normal murine enzyme 0.9:1.0:0.7.This work was supported by the Minister für Wissenschaft und Forschung des Landes Nordrhein-Westfalen, West Germany and of the Fonds der Chemie, West Germany, and forms part of the md thesis of A. Vrbica.     

Reconstitution of lipoproteins. II. Lipid-protein interaction between dimyristoyl-lecithin and dimyristoyl-lecithin:cholesterol vesicles and purified apolipoprotein C-I and C-III2 studied by isomeric spin-labelled lecithins

The reconstitution of purified apolipoprotein C-I and C-III2 with sn-3-dimyristoyl-lecithin and sn-3-dimyristoyl-lecithin:cholesterol (10:1) vesicles was studied by electron spin resonance spectroscopy using isomeric 5'-, 12'-, and 16'-(N-oxyl-4",4"-dimethyloxazolidine)stearoyl spin-labelled lecithin probes. Results obtained from the temperature-induced changes of lipoprotein recombinants showed the hydrophilic nature of the lipid-protein interactions. The temperature-induced phospholipid phase transition, as measured by 5'-(N-oxyl-4",4"-dimethyloxazolidine)stearoyl spin-labelled lecithin probe in recombinants containing apoprotein C-1 or apoprotein C-iii2, is very broad and has a small cooperative unit indicative of extensive lipid-protein interactions occurring at the head group region of the phospholipid bilayer. When 12"- and 16'-(N-oxyl-4",4"-dimethyloxazolidine)stearoyl spin-labelled lecithins are used as probes in the same system, similar sharper and more cooperative lipid phase changes are detected. These results indicate a surface location for both apoprotein C-I and apoprotein C-III2 with respect to the phospholipid bilayer in lipoprotein recombinants with and without cholesterol.