Glutamicin CBII,a bacteriocin-like substance produced by

Corynebacterium glutamicum CBII, in the stationary phase of growth, was found to produce spontaneously a substance resembling bacteriocins by its bactericidal properties. This substance designated glutamicin CBII was observed to exhibit bactericidal activity against coryneform bacteria (12 species tested) but not against unrelated gram-positive (3) and gram-negative (3) bacteria, while its action on bacteria with no quite known relatedness to the coryneform group (14) was found to be variable. Glutamicin CBII was partially purified by precipitation with ammonium sulphate (70% saturation), selective heat precipitation and gel chromatography on Sepadex G-50. The antibacterial substance diffused through cellophane membrane with an approximate cut-off of 10000 dalton and its sedimentation coefficient was determined to be 1.1. S by ultracentrifugation. Heating at 100°C for 30 min had no effect on its activity. Glutamicin CBII was proved to be resistant to chloroform, trypsin, chymotrypsin, pronase, and subtilisin. According to its staining behaviour and ¹H NMR spectra it probably represents a glycoprotein containing only a minor protein component.

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Protein kinase C from small intestine epithelial cells

Protein kinase C activity has been identified in cytosolic and membrane fractions from rat and rabbit small intestine epithelial cells. The cytosolic fraction comprised about the 75% of total activity. Protein kinase C activity was resolved from other protein kinase activities by ion exchange chromatography. Phosphatidylserine or phosphatidylinositol were required for protein kinase C to be active. In addition, the activity was enhanced by the presence of a diacylglycerol. Diolein and dimyristin were the most effective (13-14 fold activation). In the presence of phosphatidylserine and diolein, the Ka for activation by Ca2+ was 10(-7)M. The phorbol ester TPA substituted for diacylglycerol in activating protein kinase C. Brush border and basolateral membranes contained protein kinase C activity, although the specific activity of the basal lateral membranes was four-fold higher than the specific activity of the brush border membranes. The presence of PKC in small intestine epithelial cells might have important implications in the Ca2+ mediated control of ionic transport in this tissue.     

The use of gold-substituted silver-intensified diaminobenzidine (DAB) and non-intensified DAB for simultaneous electron microscopic immunoperoxidase labeling of tyrosine hydroxylase and glutamic acid decarboxylase immunoreactivity in the rat medial preoptic area

An improved gold-substituted silver intensification procedure for the peroxidase-diaminobenzidine (DAB) reaction product was developed. The method was applied in the rat medial preoptic area to label tyrosine hydroxylase (TH)-immunoreactive profiles. Following the gold toning, the same sections were immunostained for glutamic acid decarboxylase (GAD) immunoreactivity with non-intensified peroxidase-DAB. Single DAB-labeled GAD axons were found in symmetric synaptic connection with unlabeled dendrites as well as with gold-toned immunoperoxidase-containing TH neurons.     

Properties of free and bound Citrobacter freundii lipopolysaccharides

Culture medium content of free lipopolysaccharide (LPS) components spontaneously released from a Citrobacter freundii culture grown in minimum synthetic medium was determined during early (8-hr culture) and late (24-hr culture) phases of growth. As judged by Limulus-lysate test, free LPS occurred in the medium as early as after 8 hrs of incubation, i.e. at the beginning of log growth phase. As the culture continued to grow the LPS amount released into culture medium kept rising, reaching 30% of endotoxin present in 24-hr Citrobacter culture. The released LPS complex was isolated by separation and its physicochemical, immunochemical and biological properties were determined and compared with those of cell-bound endotoxin recovered from cells by phenol extraction. Comparisons revealed distinct differences in the chemical composition and the degree of heterogeneity; free LPS was less heterogeneous. Immunologically, free LPS differed from bound LPS in the structure of macromolecules, but was identical with it in some antigenic determinants. The biological activity of free LPS preparation was greater than that of cell-bound LPS.     

Arbovirological survey in Silica plateau area, Roznava District, Czechoslovakia

The serosurveys conducted in the Silica plateau area of the Slovak karst region revealed the presence of specific neutralizing antibody against tick-borne encephalitis (TBE) virus in 18% of local inhabitants (33 examined, mostly goats and sheep farmers), 54% of goats (26 examined), 18% of sheep (120 examined) and 13% of cattle (60 examined), against Lipovník (LIP) virus in 30% of inhabitants, 88% of goats, 55% of sheep and 45% of cattle, and against Bhanja (BHA) virus in 27% of inhabitants, 46% of goats, 29% of sheep and 23% of cattle. The results of hemagglutination-inhibition tests with TBE and BHA antigens were analogous. A detailed analysis of these serologic data points to a recent enhancement of the circulation of LIP and BHA viruses and to a very low TBE virus activity in this natural focus of arboviral infections. The immunological surveys of the 32 former "Roznava disease" patients, conducted 25 years after an extensive epidemic of a TBE virus infection that originated in Roznava in 1951, revealed the presence of neutralizing (and also hemagglutination-inhibiting) antibodies against TBE virus in as many as 78% of cases. Antibodies against LIP and BHA viruses were also detectable in the sera of 16% and 9%, respectively, of these individuals. Populations of the ectoparasites examined for the presence of arbovirus comprised 231 Ixodes ricinus, 806 Dermacentor marginatus and 204 Haemaphysalis punctata ticks and 117 specimens of the louse-flies Melophagus ovinus. Two strains of arbivirus that were antigenically related to Lipovník and Tribec viruses belonging to a group of Kemerovo viruses were isolated from male and female I. ricinus ticks collected from cattle.     

Lowering of pH does not directly affect the junctional resistance of crayfish lateral axons

Summary The effect of pH was tested on the junction between crayfish lateral axons. By means of a glass capillary inserted into one of the axons, one side of the nunction was perfused with solutions of known pH while the junctional resistance,R _j, was monitored. Integrity of the gap junction was checked electron microscopically.R _j remained unchanged when the pH of the perfusate was lowered from 7.1 to 6.0. However, when the pH of the unperfused side of the junction was lowered by substituting acetate for chloride in the external solution,R _j rose, attesting to the integrity of the junction and its capacity to uncouple in the perfused state. We suggest that H⁺ does not affect the junctional channels directly, but acts through an intermediary which is inactivated or removed by the perfusion.     

What is the correct value for Na, K-ATPase activity in homogenates of cerebral cortex?

Activity of Na, K-ATPase in homogenates of fresh cerebral cortex of rats was compared with that of cortex frozen under different conditions. Activity yields after rapid in situ freezing of the exposed cerebral cortex were twice, higher (26.1 U) than in homogenates of the fresh cortex (13.3 U). Fresh brain kept on ice for 60 and 300 s and subsequently frozen in liquid nitrogen yielded activities comparable to those of the tissue frozen in situ (24.1 U and 24.9 U for 60 s and 300 s periods, respectively). Inhibition of Na, K-ATPase by 10(-7) M vanadate was significantly stronger (38%) in homogenates of the fresh brain then in those of the cortex frozen in situ (28%). High Na, K-ATPase activity (47.6 U) in suspensions of synaptosomal membranes (SM) prepared from fresh cortical homogenates was only slightly inhibited by 10(-7) M vanadate (12%). Various treatments of homogenates or SM suspensions, like increase of piston rotation speed, repeated freezing and thawing procedure or vigorous shaking did not significantly affect the enzyme activity. Mg-ATPase activity and its sensitivity to vanadate was also modified by tissue treatment but the effect was much less pronounced.     

Taurine Levels in Discrete Brain Nuclei of Rats

Concentrations of taurine have been measured in 44 microdissected rat brain nuclei or areas. Taurine is ubiquitously present and distributed unevenly in the rat brain: the ratio of the highest (pyriform cortex) to lowest (midbrain reticular formation) concentrations is 4.7:1. High taurine levels were found in cerebral cortical areas, caudate-putamen, cerebellum, median eminence, and supraoptic nucleus. Acute pain stress reduced taurine levels in the hypothalamus and the lower brainstem nuclei but not in cortical areas. Increased locomotor and behavioral activities following a high dose of amphetamine elevated taurine concentrations significantly in the substantia nigra and locus ceruleus.     

Enhancive and suppressive effects of cytomegalovirus on human lymphocyte responses in vitro.

Virus-specific lymphocyte proliferation in the presence of cytomegalovirus (CMV) without and with monocytes was studied in healthy persons. Three categories of lymphocyte response could be distinguished: seropositive low responders, naturally high responders, and lymphocyte populations responding well to CMV antigen in the presence of added CMV-incubated autologous monocytes. This latter category could be identified by preincubating autologous monocytes with CMV. CMV-seronegative persons were nonresponders. Early CMV antigens were produced in monocytes but not in lymphocytes by all CMV isolates. Infection of monocytes as detected by antibody to early viral protein did not appear to abort the antigen-presenting ability. The virus-specific responding lymphocytes were mainly of the T4+ phenotype. In contrast, addition of CMV to polyclonal mitogens significantly suppressed total lymphocyte DNA synthesis. CMV thus may have an enhanced virus-specific stimulatory effect on lymphocytes together with monocytes but a suppressive effect on the total lymphocyte population.     

Long-term hyperalgesia in rats induced by neonatal administration of vasopressin antiserum

Vasopressin antiserum was given to two day old rats and the nociceptive thresholds were evaluated three months later. The rats were hypersensitive to pain when electrical current, but not heat, was used as the noxious stimulus. These animals were also insensitive to cold-water swim, a non-opioid form of stress analgesia. The vasopressin content in the pituitary or in the hypothalamus was not however modified by the neonatal treatment. The present results suggest a physiological role for vasopressin in non-opioid pain inhibitory systems.