Stability of neuronal and glial marker enzymes in post-mortem rat brain

The enzymatic activities in post-mortem rat brain kept at 4°C and at 25°C were determined for a number of enzymes localized in specific cell types in the central nervous system. Choline acetyltransferase (CAT), glycerol-3-phosphate dehydrogenase (GPDH), glutamine synthetase (GS), lactate dehydrogenase (LDH) and 2,3-cyclic nucleotide phosphohydrolase (CNPase) were found to be very stable at both 4°C and 25°C with only slight, if any, losses of activity being seen even at periods as long as 72 hr. Glutamic acid decarboxylase (GAD) activity was less stable than that of the other enzymes. In brains kept at 4°C GAD activity was stable out to 24 hr after which it began to decline rapidly to 65% of control at 72 hr. In brains kept at 25°C, GAD activity was stable for 6–8 hr and then began to steadily decline to 58% of control at 24 hr and 29% of control at 72 hr. Assuming that these enzymes have similar stabilities in post-mortem human brain, the effect of post-mortem delay in processing tissues may be of lesser significance than other factors with regard to the measured enzyme activities in human brain samples.     

Proteolytic activity of black-pigmented Bacteroides strains

Abstract The proteolytic activity of several black-pigmented Bacteroides species was measured. Bacteroides gingivalis was the only species having collagenolytic activity. General proteolytic activity on gelatin and Azocoll was shown in cultures of B. gingivalis, B. asaccharolyticus, B. endodontalis, B. intermedius, B. corporis and to a lesser extent B. melaninogenicus; B. loescheii did not show proteolytic activity. When culture filtrates were tested, B. gingivalis showed high cell free proteolytic activity, whereas the other species had only very weak cell free activity. Growth curves of B. gingivalis revealed two distinct proteolytic activities; general proteolytic activity was found during the logarithmic growth phase, whereas a second peak containing high collagenolytic activity was found after prolonged incubation of cells showing autolysis.     

Accumulation of porphyrins and pyrrole pigments by Staphylococcus aureus ssp. anaerobius and its aerobic mutant

Abstract The anaerobic, Gram-positive coccus Staphylococcus aureus ssp. anaerobius and its aerobic mutant MVF-SR, when kept under anaerobic conditions, excreted coproporphyrin (mainly type III) into the medium and enriched uroporphyrin (mainly type I) within the cells.
The rate of porphyrin synthesis stayed practically unaltered when the growth medium was supplemented with 50 μ g/ml 5-aminolevulinic acid (ALA), but was significantly enhanced upon supplementation with hemin (0.5 μ g/ml). When hemin and ALA were given simultaneously, a more than two-fold increase in porphyrin production compared to normal growth medium was observed. These observations indicate a stimulation of porphyrin synthesis in S. aureus by hemin.
An as yet unidentified violet pigment with an intense red-violet fluorescence under UV light ( λ = 366 nm) was found to be present in considerable amounts in cells of S. aureus ssp. anaerobius , whereas the supernatant medium of aerobically grown cells of the mutant MVF-SR contained an equally unidentified blue, non-fluorescing pigment.     

Adenine nucleotide content and energy charge of Bacillus megaterium during batch growth in low-phosphate medium

Abstract The effect of a low phosphate concentration on intracellular adenine nucleotides, oxygen consumption and poly-β-hydroxybutyric acid synthesis, was investigated with batch cultures of Bacillus megaterium . At low phosphate concentrations the cells contained much larger amounts of poly-β-hydroxybutyric acid, but displayed lower adenylate energy charge and oxygen uptake than did control cells. The ratio of ATP to ADP was much greater in the control cells. The levels of ATP and AMP were lower in low-phosphate cells.     

Temporal Distribution of [3H]-Imipramine Binding in Rat Brain Regions is Not Changed by Chronic Methamphetamine

Specific binding of [³H]-imipramine in the rat suprachiasmatic nuclei, occipital cortex and caudate putamen underwent significant and replicable changes throughout 24 hr under a light-dark cycle or under constant conditions. Daily variations were also found in the medial and dorsal raphe nuclei and the lateral hypothalamus. Methamphetamine, a psychoactive drug with marked effect on circadian rhythms in physiological and hormonal parameters and adrenergic receptors, did not have any significant effect on imipramine binding rhythms in eight discrete brain regions. Thus a drug known to reduce serotoninergic neurotransmission did not change characteristics of the modulatory binding site related to serotonin uptake.     

Cytoarchitectonic localization of foci of electrocortical activity accompanying focused attention in cats

Beta electrocorticographic rhythms (30-45 Hz) develop during focused immobile attention within two distinct foci in cats. A multiple electrode exploration was performed, followed by post-mortem histological analysis, to determine the precise localization of these foci. Electrode tips recording beta rhythms in the waking attentive cat were located: in motor areas (Brodmann's areas 4 and 6), in a band extending from the postcruciate cortex to the walls of the presylvian sulcus, crossing the frontal pole (anterior beta focus); in the posterior parietal associative area 5a, along the divisions of the ansate sulcus (posterior beta focus). The two foci are separated by somatic areas 3, 2 and 1, where beta rhythms were never recorded. The location of the posterior focus may suggest that area 5 is, in the cat as it is in the monkey, involved in motor control.     

A comparative study of salivary secretion by parotid and mandibular glands of anaesthetized Capra hircus: effect of pilocarpine

A study was made of basal secretion and the effect of the infusion of pilocarpine on the flow and composition of saliva in the parotid and mandibular glands of the anaesthetized lactating goat. In the parotid gland there was a basal flow (1.6 +/- 0.29 microliter/min) which was not present in the mandibular gland. There is a statistically significant dose-effect relationship between pilocarpine and salivary flow in both glands. Salival composition and its variation with respect to the flow of saliva did not conform to either of the two glands to an exclusive monogastric or ruminant model.     

Stress by forced swimming in the rat: effects of mianserin and moclobemide on GABAergic-monoaminergic systems in the brain

The stress caused by forced swimming in male rats provoked a decrease in brain NA levels without changes in DA and 5-HT content, MAO and GABAergic activity. Acute or chronic treatment with mianserin did not modify the decrease in NA concentration in the brain of stressed rats. Acute treatment with moclobemide (IMAO) did not modify the decrease in NA content caused by stress; chronic treatment blocked the decrease in NA content in stressed rats.     

Poly(ADP-ribose) accessibility to poly(ADP-ribose) glycohydrolase activity on poly(ADP-ribosyl)ated nucleosomal proteins

Hydrolysis of protein-bound 32P-labelled poly(ADP-ribose) by poly(ADP-ribose) glycohydrolase shows that there is differential accessibility of poly(ADP-ribosyl)ated proteins in chromatin to poly(ADP-ribose) glycohydrolase. The rapid hydrolysis of hyper(ADP-ribosyl)ated forms of histone H1 indicates the absence of an H1 dimer complex of histone molecules. When the pattern of hydrolysis of poly(ADP-ribosyl)ated histones was analyzed it was found that poly(ADP-ribose) attached to histone H2B is more resistant than the polymer attached to histone H1 or H2A or protein A24. Polymer hydrolysis of the acceptors, which had been labelled at high substrate concentrations (greater than or equal to 10 microM), indicate that the only high molecular weight acceptor protein is poly(ADP-ribose) polymerase and that little processing of the enzyme occurs. Finally, electron microscopic evidence shows that hyper(ADP-ribosyl)ated poly(ADP-ribose) polymerase, which is dissociated from its DNA-enzyme complex, binds again to DNA after poly(ADP-ribose) glycohydrolase action.