Stimulation of some litter-decomposing basidiomycetes by shikimic acid

Shikimic acid, which constitutes 1.5-2.5% of the dry matter in needles of Scots pine, was found to stimulate the growth of various litter-decomposing basidiomycetes of the genera Marasmius, Mycena and Xeromphalina in a synthetic nutrient medium. Out of eighteen litter-decomposing species, ten were stimulated by shikimic acid, wheras the eight mycorrhizal and four wood-rotting species tested were not affected. Maximal effect was obtained at a concentration of ca 2 m M . Growth experiments at varying pH-values indicated active uptake of shikimic acid. Even in the presence of aromatic amino acids, shikimic acid stimulated the growth of the fungi. In certain species the strong inhibiting effect of phenylalanine, tyrosine and tryptophan, when added simultaneously, was reversed in the presence of shikimic acid. Fungi which were stimulated by shikimic acid were also able to use this compound as their sole carbon source. Maximal stimulating effect of shikimic acid occurred when glucose had been added at optimal concentration.     

Behavioral and biochemical assessment of time-related changes in globus pallidus and striatal dopamine induced by intranigrally administered neurotensin

Microinjection of neurotensin (NT; 2 and 5 μg) into the substantia nigra zona compacta caused an increase in dopamine (DA) and DA metabolites in the rodent globus pallidus and striatum which persisted for at least 20 hours after peptide administration. Similar NT treatments given unilaterally into the nigra caused circling away from the injected side in amphetamine-pretreated rats, but were without effect when microinjected into saline-pretreated animals. Circling also occurred when the animals were given amphetamine 20 hours after intranigral NT administration. Contralateral rotation was observed with unilateral intranigral injections of gamma-hydroxybutyric acid (GHB; 400 μg) or with lower intranigral GHB doses (250 μg) in amphetamine-pretreated animals. The effects of GHB and NT differed in the manner in which the animals rotated as well as in the profile of DA and DA metabolite changes induced by these drugs. These studies indicated that: (1) dopaminergic functions of the globus pallidus are influenced, like the striatum, by manipulations of the substantia nigra; (2) NT and GHB likely act via different mechanisms to effect nigral dopamine-containing cells; and (3) NT was capable of inducing changes in dopamine neurons which had long term consequences.     

Triterpenes from Periandra dulcis roots

Three oleanane triterpenes were isolated from the roots of Periandra dulcis,and identified as 3β-hydroxy-25-al-olean-18-en-30-oic acid (periandric acid I), 3β-hydroxy-25-al-olean-12-en-30-oic acid (periandric acid II) and 3-oxo-25-hydroxy-olean-12-en-30-oic acid. The former two compounds (periandric acids I and II) were identical with the aglycones obtained by hydrolysis of periandrin I and II, respectively and the latter one was a new triterpene.     

Phytase production byAspergillus ficuum on semisolid substrate

Summary Phytase production byAspergillus ficuum was studied using solid state cultivation on several cereal grains and legume seeds. The microbial phytase was used to hydrolyze the phytate in soybean meal and cotton seed meal. Wheat bran, soybean meal, cottonseed meal and corn meal supported good fungal growth and yielded a high level of phytase when an adequate amount of moisture was present. The level of phytase production on solid substrate was higher than that obtained by submerged liquid fermentation. Higher levels of phosphorus (more than 10 mg Pi/100 g substrate) in the growth medium (static culture) inhibited phytase synthesis, and the degree of phosphorus inhibition was less apparent in semisolid medium than in liquid medium. A static cultivation on semisolid substrate produced a higher level of phytase (2-20-fold) than that obtained by agitated cultivation. The minimal amount of water required for growth and enzyme production on those substrates was about 15%, while the optimum level for phytase production was between 25 and 35% and that for cell growth was above 50%. Optimum pH for phytase production was between 4 and 6.A ficuum grew well on raw (unheated) substrate containing a minimal amount of water and produced as much phytase as on heated substrate. About half of the phytic acid in soybean meal and cottonseed meal was hydrolyzed by treatment withA. ficuum phytase.     

Enzymes metabolizing dimethylamine, trimethylamine and trimethylamine N-oxide in the yeast Sporopachydermia cereana grown on amines as sole nitrogen source

Abstract Sporopachydermia cereana , an ascosporogenous yeast, grew on dimethylamine, trimethylamine or trimethylamine N -oxide as sole nitrogen sources and produced mono-oxygenases for dimethylamine and trimethylamine that were significantly more stable than the corresponding enzymes found in Candida utilis . No trimethylamine mono-oxygenase activity was found in S. cereana grown on dimethylamine. In cells grown on trimethylamine N -oxide (but not on the other nitrogen sources), evidence for an enzyme metabolizing the N -oxide, possibly an aldolase, but more probably a reductase was obtained. All these activities showed a similar requirement for the presence of FAD or FMN in the extract buffer during isolation to retain activity. Amine mono-oxygenase activities showed a similar sensitivity to inhibitors, including proadifen hydrochloride and carbon monoxide as the corresponding enzymes in C. utilis . The trimethylamine N -oxide-dependent oxidation of NADH was more sensitive to inhibition by EDTA, N -ethylmaleimide and β-phenylethylamine than the mono-oxygenases, and less sensitive to KCN, and activity was significantly higher with NADPH than was observed with the 2 mono-oxygenases.     

Cyclic nucleotide phosphodiesterases in larval brain of wild type and dunce mutant strains of Drosophila melanogaster: isoenzyme pattern and activation by Ca2+/calmodulin

Like adult heads and whole flies, larval brains of wild type Drosophila melanogaster contain two major soluble cyclic nucleotide phosphodiesterases, forms I and II. Larval brains of the learning-defective mutant strain, dunceM11, contain only the form I enzyme. In both wild type and dunce strains the form I enzyme is activated by Ca2+/calmodulin. A time-dependent loss of this Ca2+ activation was observed.     

Interaction of fatty acids with lipid bilayers

We present a method by which it is possible to describe the binding of fatty acids to phospholipid bilayers. Binding constants for oleic acid and a number of fatty acids used as spectroscopic probes are deduced from electrophoresis measurements. There is a large shift in $\text{p}\text{K}$ value for the fatty acids on binding to the phospholipid bilayers, consistent with stronger binding of the uncharged form of the fatty acid. For dansylundecanoic acid, fluorescence titrations are consistent with the binding constants derived from the electrophoresis experiments. For 12-(9-anthroyloxy)stearic acid, fluorescence and electrophoresis data are inconsistent, and we attribute this to quenching of fluorescence at high molar ratios of 12-anthroylstearic acid to phospholipid in the bilayer.