Biochemical changes of rat brain membranes with aging

Modification of membrane composition and enzymatic activities both in total brain homogenate and purified synaptic plasma membrane of 3 and 24 month old rats has been investigated. Protein, cholesterol and phospholipid content and (Na+, K+)ATPase and 2',3' cyclic nucleotide phosphohydrolase activities were determined. The major changes occurred in the whole homogenate where a general increase in total protein and cholesterol content with age and a significant increase of the cholesterol/phospholipids molar ratio has been detected. In S.P.M. aging process induced a decrease of protein, cholesterol and phospholipids content associated with an increased membrane viscosity and a decrease of delta E. These data are consistent with a change in the structural organization and in the distribution pattern of different cell population in the aging brain. A possible artifactual effect of freezing on the reported parameter is also discussed.     

Lathyrus nissolia subsp.futakii subsp. nova in der Tschechoslowakei

A new subspecies,Lathyrus nissolia L. subsp.futakii Chrtková subsp. nova is described from East Slovakia. The diacritical characters are: high and rich branched stems, 50–110 cm long and larger, 10–12 mm long, bright orange-red flowers. It differs also in ecology, growing in wet lowland forests with the level of the ground water up to 15 cm over the earth also in summer.     

Quantitative changes in potassium,sodium, and calcium in the submaxillary salivary gland and blood serum of rats exposed to 2880-MHz microwave radiation

Na⁺, K⁺, and Ca²⁺ concentrations in the blood serum and submaxillary salivary gland (SSG) were investigated in adult, male rats exposed to 2880-MHz microwaves modulated with 1.5-μs pulses at a pulse repetition rate of 1000 Hz or in a hyperthermal environment. Rats were exposed, one at a time, for 30 min to microwaves producing a specific absorption rate (SAR) of: 4.2, 6.3,6.8,8.4, 10.8, or 12.6 W/kg, or were sham exposed under similar environmental conditions. In a second series, one group of rats was exposed singly for 15, 30, or 60 min to microwaves producing an SAR of 9.5 W/kg and other rats were exposed for similar periods at 40 °C; and 10 rats were sham exposed. Flame photometric analysis indicated that the thresholds of microwave radiation required to induce a change in Na⁺, K⁺, and Ca²⁺ concentrations in the salivary glands are 6.8, 6.8, and 6.3 W/kg, respectively. The directions of Na⁺, K⁺, and Ca²⁺ ion shifts in exposed rats' salivary glands are similar, whether affected by microwaves or hyperthermia. Greater changes in Na⁺ and K⁺ concentrations in SSG of rats exposed to microwaves for 15 and 30 min were found than in those exposed at 40 °C. On the other hand, exposure to hyperthermia at 40 °C or to microwaves for 1 h caused Na⁺ concentration to be increased by 68.7 and 59.5% and K⁺ concentration to be decreased by 29.6 and 21.7%, respectively.     

Phylogenetic depth ofThermotoga maritima inferred from analysis of thefus gene: Amino acid sequence of elongation factor G and organization of theThermotoga str operon

Summary The gene (fus) coding for elongation factor G (EF-G) of the extremely thermophilic eubacteriumThermotoga maritima was identified and sequenced. The EF-G coding sequence (2046 bp) was found to lie in an operon-like structure between the ribosomal protein S7 gene (rpsG) and the elongation factor Tu (EF-Tu) gene (tuf). TherpsG, fus, andtuf genes follow each other immediately in that order, which corresponds to the order of the homologous genes in thestr operon ofEscherichia coli. The derived amino acid sequence of the EF-G protein (682 residues) was aligned with the homologous sequences of other eubacteria, eukaryotes (hamster), and archaebacteria (Methanococcus vannielii). Unrooted phylogenetic dendrogram, obtained both from the amino acid and the nucleotide sequence alignments, using a variety of methods, lend further support to the notion that the (present) root of the (eu)bacterial tree lies betweenThermotoga and the other bacterial lineages.     

Urinary but Not Brain Isatin Levels Are Reduced in Germ-Free Rats

Germ-free rats excreted considerably smaller amounts of the monoamine oxidase-inhibiting compound isatin than the substantially larger output by conventional animals of the same strain, although concentrations in brain and other tissues were similar in the two groups. Thus, isatin is likely to be elaborated both endogenously in rat tissues and "exogenously" by flora inhabiting the lumen of the alimentary tract.     

Selected chromosome counts of the Czechoslovak flora III

Chromosome numbers compared with as yet published data are given for the following 12 Phanerogams (both native species and aliens) from Czechoslovakia:Ambrosia trifida L.,Cardamine chelidonia L.,Dephne cneorum L.,Epipactis albensis Nováková etRydlo,Linum flavum L.subsp flavum, Lunaria rediviva L.,Nepeta grandiflora M.BIEB.,Reseda luteola L.,Thlaspi montanum L.,Tithymalus salicifolius (Host)Klotzsch etGarcke,Tithymalus virgultosus (Klokov) Holub andVerbascum speciosum Schrad. subsp.speciosum. The chromosome number 2n=40 is presented for the first time in autogamousEpipactis albensis Nováková etRydlo. New chromosome numbers were found inCardamine chelidonia L. (2n=32) and inTithymalus salicifolius (Host) Klotzch etGarcke (2n=40). Known but less frequent cytotypes are reported inLinum flavum L. subsp.flavum (2n=28) and inVerbascum speciosum Schrad. subsp.speciosum (2n=30).     

The effect of phosphate deficiency on mitochondrial activity and adenylate levels in bean roots

Bean plants ( Phaseolus vulgaris ) were grown for 16–20 days with or without phosphate in Knop nutrient medium. It was found in previous experiments that for roots grown on a P_i-deficient medium respiration is mainly carried out by the cyanide-insensitive pathway. Mitochondria isolated from—P_i, roots had poor respiratory control and their respiration exhibited 62% inhibition by cyanide and was inhibited (30%) by salicylhydroxamic acid (SHAM). In contrast, mitochondria obtained with control (+P_i) roots had respiratory control and ADP/O ratios typical for succinate as the substrate; their respiration was inhibited to 95% by cyanide and insensitive to SHAM. The integrity of mitochondrial membranes was similar in both types of mitochondria. Cytochrome oxidase activity, however, was about 20% lower in -P_i mitochondria, but the cytochrome composition was the same in both types of mitochondria. The cytochrorae pathway was not operating at full capacity in mitochondria isolated from—P_i roots but the alternative oxidation pathway participated in a great part in mitochondrial respiration, similar to in vivo whole roots. The participation of the non-phosphorylating., alternative pathway decreased the respiratory control ratio in mitochondria and had an effect on the total adenine nucleotide pool and energy charge values which were lower (16 and 13% respectively) in -P_i roots. About 50% lower ADP and 20% lower ATP levels were observed whereas AMP levels were several times higher.     

Seasonal commitment of HMGCoA reductase activity to vitellogenin production

In female frogs (Rana Esculenta) during gametogenesis the cholesterol synthesized in the liver by 3-hydroxy-3-methylglutaryl coenzyme A reductase is mostly exported into the blood and taken up by the oocytes.In order to understand the fate of the neosynthesized cholesterol, female and male frogs and estrogenized male controls were injected with the labelled precursor¹⁴C mevalonate.In females and in estrogenized controls, mevalonate-derived radioactivity is found in a plasmatic lipoprotein that has been identified as vitellogenin by immunological detection.The increased 3-hydroxy-3-methylglutaryl coenzyme A reductase activity present in females in Fall is likely to be committed to provide cholesterol for the lipidation of this cholesterol-rich protein.