Absence of ganglioside GM1 in astroglial cells from newborn rat brain

An immunohistochemical method utilizing anti-ganglioside GM1 antiserum combined with the peroxidase-antiperoxidase technique was applied to a mixed cell population in primary cultures of newborn rat brain. Ganglioside GM1 was demonstrated to be present in neurons and oligodendroglia, but was absent in astroglia. This demonstration was confirmed using a newly developed biotinylated choleragen-avidin-peroxidase procedure. Primary cultures from newborn rat brain cells that had been subjected to a single treatment with trypsin (first passage) and then cultured for 14 days were predominately (95%) composed of astrocytes that stained positively for glial fibrillary acidic protein but were negative for GM1 ganglioside. This preparation contained only 0.34 nmol ganglioside NeuNAc per mg protein compared to 23.9 nmol gangliosidic NeuNAc/mg protein for a five day culture of newborn rat brain mixed cell culture that had not been subjected to passage. Prolongation of culture time from 5 to 21 days in the latter preparation reduced the ganglioside NeuNAc content to 4.9 nmol gangliosidic NeuNAc/mg protein as the proportion of astrocytes in the culture increased. Ganglioside GM1 could not be detected by TLC analysis of the lipid extract obtained from the “pure” astrocyte culture, although small amounts of GM3 and some polysialogangliosides were detected. About half of the label incorporated upon 24 h incubation of astrocytes in the presence of $\text{N-[}{}^3\text{H]acetylmannosammine}$ appeared in ganglioside GM3. It is concluded that astrocytes in mixed cell primary cultures from newborn rat brain, as well as astrocytes in astroglial preparations derived from such cultures, do not contain ganglioside GM1.     

Bacterial Plasmids in Antarctic Natural Microbial Assemblages

Samples of psychrophilic and psychrotrophic bacteria were collected from sea ice, seawater, sediments, and benthic or ice-associated animals in McMurdo Sound, Antarctica. A total of 155 strains were isolated and tested for the presence of plasmids by DNA agarose gel electrophoresis. Thirty-one percent of the isolates carried at least one kind of plasmid. Bacterial isolates taken from sediments showed the highest plasmid incidence (42%), and isolates from seawater showed the lowest plasmid incidence (20%). Plasmids were significantly more frequent in the strains which had been first isolated from low-nutrient media (46%) than in the strains which had been isolated from high-nutrient media (25%). Multiple forms of plasmids were observed in two-thirds of the plasmid-carrying strains. A majority of the plasmids detected were estimated to have a mass of 10 megadaltons or less. Among 48 plasmid-carrying strains, 7 showed antibiotic resistance. It is concluded that bacterial plasmids are ubiquitous in natural microbial assemblages of the pristine marine ecosystem of Antarctica.     

Hepatic dysfunction in primary hypothyroidism

Twenty-seven patients with primary hypothyroidism were studied to evaluate the relationship between hepatic function and thyroid hormone deficiency in this disorder. In hypothyroidism, hypergammaglobulinemia was found in 71%, elevated glutamic oxaloacetic transaminase (GOT) in 48%, high lactic dehydrogenase (LDH) in 58%, hypercholesteremia in 52% and low elimination rate constant of indocyanin green (KICG) in 44%. In each criterion of liver function, these patients were divided into two groups, normal level and abnormal level group, respectively. T3 and T4 in patients with abnormal levels of GOT, glutamic pyruvic transaminase (GPT), gamma-glutamyl transpeptidase (gamma-GTP), leucine aminopeptidase (LAP), alkaline phosphatase (ALP) and 45 minutes retention rate of bromsulphalein (BSP) were not different from those in the normal level group. However, T3 and T4 in patients with abnormal levels of LDH, cholesterol, cholinesterase (ChE) and KICG were lower than those in the normal level group. The abnormal KICG group had a statistically higher cardio-thoracic ratio (CTR) than the normal group (65.7 +/- 18.8% vs 50.4 +/- 8.3%, p less than 0.05). In patients with pericardial effusion, CTR was 65.9 +/- 14.6%, while that in patients without pericardial effusion was 49.9 +/- 7.5% (p less than 0.05). These abnormalities of liver function were normalized in all cases after hormone replacement therapy. Liver biopsy in three cases disclosed normal liver in two cases and mild infiltration of monocyte into Glisson's capsule in one case.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of taurine and γ-aminobutyric acid on akinesia and analgesia induced by D-Ala2-Met-enkephalinamide in rats

Effects of taurine or γ-aminobutyric acid (GABA) on akinesia and analgesia induced by D-Ala²-Met-enkephalinamide were investigated in rats. Administration of taurine (dose range: 2.375×10^?2 M–9.5×10^?2 M/10 μl) into the left lateral ventricle 10 min prior to the injection of D-Ala²-Met-enkephalinamide (50 μg/10 μl) produced a dose-dependent reduction in the duration of akinesia and to some extent of analgesia, as estimated at 30 min and 60 min following the enkephalinamide injection; at the first estimation-time (10 min), taurine did not alter the duration of akinesia or that of analgesia. The median effective dose (ED₅₀) for akinesia determined at 60 min after D-Ala²-Met-enkephalinamide was 5 times greater and that for analgesia assessed at the same time was 1.7 times greater in taurine-treated rats than the respective doses in control animals. Administration of GABA under similar experimental conditions produced a dose-dependent reduction in the duration of analgesia from the initial estimation time (10 min) following the injection of D-Ala²-Met-enkephalinamide. The ED₅₀ for analgesia determined at 30 min after D-Ala²-Met-enkephalinamide was 3 times greater in GABA-treated rats than in control animals. Unlike the effects of taurine, GABA did not alter the duration of akinesia. Neither the duration of akinesia nor that of analgesia was modified by taurine or GABA alone in rats tested 9 min after the injection of each amino acid. These findings suggest that taurine may promote a recovery from both akinesia and analgesia, while GABA decreases only the analgesia induced by D-Ala²-Met-enkephalinamide.     

Production of D-phenylglycine-related amino acids by immobilized microbial cells

Bacterial dihydropyrimidinase was shown to catalyze the hydrolytic cleavage of various 5-substituted hydantoins to the corresponding N-carbamyl-D-amino acids under alkaline conditions. Therefore, an enzymatic method for preparing the D-forms of phenylglycine-related amino acids was developed using immobilized bacterial cells with high enzyme activity. Alkalophilic bacteria were a good enzyme source for this process. The process is simple and economical for use in the production of various amino acids with the D-configuration.     

Troponin in embryonic chick skeletal muscle cells in vitro. An immunoelectron microscope study

The fine structurel distribution of troponin on thin filaments in developing myofibrils was investigated by the use of immunoelectron microscopy. Embryonic chick skeletal muscle cells grown in vitro were treated with antibodies against each of the troponin components (troponin T, I, and C) from adult chicken muscles. Each antibody was distributed along the thin filaments with a period of 38 nm. It is concluded that these newly synthesized regulatory proteins are assembled at their characteristic position from the initial phases of myofibrillogenesis.     

Glucose uptake in mouse brain regions under hypoxic hypoxia

Glucose uptake of individual structures within the brain was studied by dry-autoradiography with 2-deoxy-D-[¹⁴C(U)]glucose under mild hypoxic hypoxia (12% O₂88% N₂ or 9% O₂91% N₂ for 1 hr). Glucose consumption in the whole brain was estimated by combined gas chromatography-mass spectrometry (GC-MS). Mild hypoxia increased the optical density of the autoradiograph in all regions. The deuterated G-6-P (Glucose-6-phosphate) synthesized from deuterated glucose decreased significantly with 9% O₂ hypoxia (P<0.05). The ratio of the deuterated G-6-P to deuterated glucose, a more appropriate indicator of glucose utilization than the concentration of deuterated G-6-P, decreased significantly with 12% O₂ hypoxia (P<0.01). The hippocampus, white matter, colliculus superior, and corpus geniculatum laterale appeared to be particulary sensitive to hypoxia.     

Natural occurence of a biopolymer, poly (adenosine diphosphate ribose).

Evidence for the natural occurrence of poly(adenosine diphosphate ribose) in vivo was obtained using a sensitive radioimmunoassay and poly(adenosine diphosphate ribose) glycohydrolase, which specifically hydrolyzes poly(adenosine diphosphate ribose). Calf thymus, liver, kidney, brain, pancreas and spleen contained poly(adenosine diphosphate ribose). Naturally occurring poly(adenosine diphosphate ribose) in calf thymus is composed of molecules of various chain lengths, like that synthesized by an in vitro system. Calf thymus was estimated to contain about 0.02 microgram/mg DNA of poly(adenosine diphosphate ribose).     

Isolation and characterization of a plaque-forming lambda bacteriophage carrying a ColE1 plasmid

A plaque-forming lambdaimm434 bacteriophage carrying the entire genome of colicinogenic factor E1 has been isolated and characterized. This phage, lambdaimm434ColE1, can lysogenize as a stable plasmid within a recombination-deficient Escherichia coli cell that lacks the normal attachment site for lambda phage. Furthermore, it has been found that lambdaimm434ColE1 phage carrying amber mutations in the O and P genes of the lambda genome, i.e., lambdaimm434OamPamColE1, behaves as a plaque-forming phage, and this finding suggests that the ColE1 factor DNA permits replication of the DNA of the plaque-forming phage.