Effect of oleic acid on mitochondrial cytochrome c oxidase activity

Both Km and Vmax values of cytochrome c oxidase for cytochrome c were elevated in oleic acid-incorporated mitochondria, whereas the amount of oleic acid incorporated into submitochondrial particles was smaller than that into mitochondria and the fatty acid had little effect on the enzyme activity. The degree of change in the bulk membrane fluidity was, however, almost the same in mitochondria and submitochondrial particles. Solubilized cytochrome c oxidase was insensitive to the effect of oleic acid. Oleic acid may act as a modifier of the interaction between cytochrome c oxidase and membrane lipids.     

Construction of protocellular structures under simulated primitive earth conditions

We have developed experimental approaches for the construction of protocellular structures under simulated primitive earth conditions and studied their formation and characteristics. Three types of envelopes; protein envelopes, lipid envelopes, and lipid-protein envelopes are considered as candidates for protocellular structures. Simple protein envelopes and lipid envelopes are presumed to have originated at an early stage of chemical evolution, interaction mutually and then evolved into more complex envelopes composed of both lipids and proteins.Three kinds of protein envelopes were constructedin situ from amino acids under simulated primitive earth conditions such as a fresh water tide pool, a warm sea, and a submarine hydrothermal vent. One protein envelope was formed from a mixture of amino acid amides at 80 °C using multiple hydration-dehydration cycles. Marigranules, protein envelope structures, were produced from mixtures of glycine and acidic, basic and aromatic amino acids at 105 °C in a modified sea medium enriched with essential transition elements. Thermostable microspheres were also formed from a mixture of glycine, alanine, valine, and aspartic acid at 250 °C and above. The microspheres did not form at lower temperatures and consist of silicates and peptide-like polymers containing imide bonds and amino acid residues enriched in valine. Amphiphilic proteins with molecular weights of 2000 were necessary for the formation of the protein envelopes.Stable lipid envelopes were formed from different dialkyl phospholipids and fatty acids.Large, stable, lipid-protein envelopes were formed from egg lecithin and the solubilized marigranules. Polycations such as polylysine and polyhistidine, or basic proteins such as lysozyme and cytochromec also stabilized lipid-protein envelopes.     

Two forms of RecA-single-stranded DNA-adenosine 5'-O-(3-thiotriphosphate) complexes with different activities for cleavage of phage phi 80 cI repressor

The kinetics of cleavage of the phage phi 80 cI repressor by Escherichia coli RecA protein were studied. The rate of cleavage in the presence of single-stranded DNA (ssDNA) and either adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), ATP or dATP is very low in the first hour at 37 degrees C and then increases sharply as incubation continues. The initial rate of cleavage of the repressor is greatly increased by incubating the RecA protein with ssDNA prior to addition of ATP gamma S and the repressor. However, when ATP gamma S is present during preincubation of RecA protein with ssDNA, the stimulatory effect of preincubation is greatly reduced. This difference in the effect of preincubation in two different conditions can be explained by formation of RecA-ssDNA-ATP gamma S complexes with different activities for cleavage of the repressor. The active complex is formed by binding of ATP gamma S to a complex of RecA protein and ssDNA. However, when the RecA protein binds to ATP gamma S prior to its binding to ssDNA, the resulting complex has no or only very weak cleavage activity toward the repressor.     

Effects of chronic bifemelane hydrochloride administration on receptors for N-methyl-d-aspartate in the aged-rat brain

We assayed N-methyl-d-aspartate (NMDA) receptors [³H]3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid ([³H]CPP) bindings) and evaluated their distribution in the brain by quantitative autoradiography in young adult and aged rats. In the young adult rats, NMDA receptors were present at relatively high concentrations in the cerebral cortex and hippocampus. In the aged rats, NMDA receptors were decreased in the nealy all areas of the brain, especially in the cerebral cortex and hippocampus. Chronic administration of bifemelane hydrochloride, a drug for sequela of cerebrovascular diseased, at a dose of 15 mg/kg/day for 14 days, markedly attenuated these decrease in NMDA receptors. Since NMDA receptors are considered to be involved in memory and learning processes, our results suggest that bifemelane hydrochloride may be applicable to the treatment of disturbed memory and learning.     

A novel and efficient method for enzymatic synthesis of high purity maltose using moranoline (1-deoxynojirimycin).

A transglycosylation reaction with moranoline (1-deoxynojirimycin) was done with soluble starch as the glucosyl donor and Bacillus macerans amylase as a cyclodextrin glycosyltransferase [EC 2.4.1.19]. The resultant transglycosylation products with moranoline, obtained by treating the reaction mixture with a strong cation exchange resin, were hydrolyzed by beta-amylase [EC 3.2.1.2] from sweet potatoes. The hydrolysate was treated with a strong cation exchange resin, and high purity maltose was obtained.     

Acute pulmonary alveolar hypoxia increases lung and plasma endothelin-1 levels in conscious rats.

To investigate the effect of pulmonary alveolar hypoxia on the synthesis and release of endothelin (ET)-1, ET-1-like immunoreactivity (-LI) levels of the lung and plasma were measured in conscious unrestrained rats under hypoxic conditions. Sixty-min exposure to alveolar hypoxia (10% O2 or 5% O2) increased the ET-1-LI level in the lung. The plasma ET-1-LI level in hypoxic rats also increased significantly. The increase of plasma and lung ET-1-LI levels were parallel to the severity of hypoxia. These results demonstrates that acute pulmonary alveolar hypoxia increases lung and plasma ET-1-LI levels in conscious unrestrained rats, suggesting a possible physiological or pathophysiological significance of ET in alveolar hypoxia.     

Somatostatin receptors in the senescent rat brain: a quantitative autoradiographic study.

To examine the effects of aging on the density and distribution of somatostatin receptors (SS-R) in the rat brain, receptor autoradiography for SS-R was carried out in rats aged 3 and 24 months using 125I-labeled Tyr11-SS-14. Autoradiograms were quantitatively assessed by an image analyzer to evaluate changes in the expression of SS-R due to senescence. Statistically significant decreases in SS-R binding were found in specific regions of the brains of senescent rats as compared to young adult rats. The regions affected included the periaqueductal gray matter (73% loss versus young adult rats), the interpeduncular nucleus (73% loss), the pontine nucleus (63% loss), the superior colliculus (46% loss), the ventral tegmental area (46% loss), the temporal cortex (39% loss), the frontal cortex (34% loss), the hippocampus (33% loss), the amygdala (27% loss) and the claustrum (26% loss). There was no significant change in SS-R expression in the spinal cord with aging. Significant reductions in SS-R binding in these brain regions may be involved in the impairment of sensory and cognitive function that can occur with aging.     

Studies on the relationship between paracoccidioidomycosis in ddY mice and their estrous cycle

The relationship between paracoccidioidomycosis in ddY mouse and its estrous cycle was studied. Adult ddY mice of both sexes were used as experimental animals. Estrous cycle of female mice was examined before inoculation of Paracoccidioides brasiliensis yeast cells and mice were divided into 5 groups such as proestrus, estrus, metestrus-I, metestrus-II and diestrus. Each mouse was inoculated intravenously with 10⁶ P. brasiliensis yeast cell units and sacrificed on day 28 after inoculation. Their internal organs were cultured, and in addition, their histopathologies were studied. As a result, there was no difference in the organ cultures among the male and the female mice of 5 groups. However, histopathologically, the female groups at estrus, metestrus-I and metestrus-II were affected more severely than the male group, and the susceptibility of the female mice to the fungus was closely related to their estrous cycles.Abbreviations BHI-D brain heart infusion agar supplemented with 1.0% of anhydrous dextrose - PAS periodic acid-Schiff techniques - PBS phosphate buffered saline solution - SD standard deviation     

Virulence and pathogenicity of human and environmental isolates of Cladosporium carrionii in new born ddY mice

Three strains of Cladosporium carrionii, two human isolates and one from a xerophilous plant, were used to study the effect of culture conditions in 106 newborn ddY mice. Growth in a complex medium (YPG) and a basal synthetic medium (BSM) was compared. Filamentous forms developed during static incubation while conidia were readily formed with shaking. Mice inoculated intraperitoneally were sacrified and autopsied after 4 weeks. Mortality was related only to sporulated exponential phase growing cells. Invasiveness ability was preserved in all experimental conditions. BSM medium that inhibited exopigment formation appeared more suitable than YPG to obtain intact cells for further studies.Biochemical and physiological alteration associated with shape changes during differentiation of vegetative cells into spores could play an important role in virulence of C. carrionii