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Biomedical subjects

M Satake

Publications and source records attributed to M Satake.

At least 289 records · Page 16Linked to original sources
PubMed1984

A multicopy phr-plasmid increases the ultraviolet resistance of a recA strain of Escherichia coli.

It has been previously reported that the ultraviolet sensitivity of recA strains of Escherichia coli in the dark is suppressed by a plasmid pKY1 which carries the phr gene, suggesting that this is due to a novel effect of photoreactivating enzyme (PRE) of E. coli in the dark (Yamamoto et al., 1983a). In this work, we observed that an increase of UV-resistance by pKY1 in the dark is not apparent in strains with a mutation in either uvrA, uvrB, uvrC, lexA, recBC or recF. The sensitivity of recA lexA and recA recBC multiple mutants to UV is suppressed by the plasmid but that of recA uvrA, recA uvrB and recA uvrC is not. Host-cell reactivation of UV-irradiated lambda phage is slightly more efficient in the recA/pKY1 strain compared with the parental recA strain. On the other hand, the recA and recA/pKY1 strains do not differ significantly in the following properties: Hfr recombination, induction of lambda by UV, and mutagenesis. We suggest that dark repair of PRE is correlated with its capacity of excision repair.

Bacteriophage lambda↗
PubMed1984

HLA antigens in Japanese patients with narcolepsy. All the patients were DR2 positive.

A surprisingly high association between an HLA-DR locus antigen and narcolepsy was revealed in the Japanese. All 40 Japanese patients with narcolepsy (22 males and 18 females) were confirmed to be DR2 positive. However, the DR2 of the patients was found to associate negatively with Bw52, whereas Bw52-DR2 is the commonest haplotype in normal Japanese population. These data suggested that a "disease" allele predisposing to narcolepsy was inherited with relatively rare haplotypes with DR2 in the Japanese.

Female↗
PubMed1984

Nucleotide sequence of the gene encoding respiratory syncytial virus matrix protein.

The amino acid sequence of the matrix protein of the human respiratory syncytial virus (RS virus) was deduced from the sequence of a cDNA insert in a recombinant plasmid harboring an almost full-length copy of this gene. It specifically hybridized to a single 1,050-base mRNA from infected cells. The recombinant containing 944 base pairs of RS viral matrix protein gene sequence lacked five nucleotides corresponding to the 5' end of the mRNA. The nucleotide sequence of the 5' end of the mRNA was determined by the dideoxy sequencing method and found to be 5' NGGGC, wherein the C residue is one nucleotide upstream of the cloned viral sequence. The initiator ATG codon for the matrix protein is embedded in an AATATGG sequence similar to the canonical PXXATGG sequence present around functional eucaryotic translation initiation codons. There is no conserved sequence upstream of the polyadenylate tail, unlike vesicular stomatitis virus and Sendai virus, in which four nucleotides upstream of the polyadenylate tail are conserved in all genes. There is no equivalent of the eucaryotic polyadenylation signal AAUAAA upstream of the polyadenylate tail. The matrix protein of 28,717 daltons has 256 amino acids. It is relatively basic and moderately hydrophobic. There are two clusters of hydrophobic amino acid residues in the C-terminal third of the protein that could potentially interact with the membrane components of the infected cell. The matrix protein has no homology with the matrix proteins of other negative-strand RNA viruses, implying that RS virus has undergone extensive evolutionary divergence. A second open reading frame potentially encoding a protein of 75 amino acids and partially overlapping the C terminus of the matrix protein was also identified.

Amino Acid Sequence↗
PubMed1984

Sequence analysis of the respiratory syncytial virus phosphoprotein gene.

A recombinant cDNA plasmid (pRSA3) containing an almost full-length copy of the mRNA encoding respiratory syncytial virus phosphoprotein was identified in a cDNA library prepared with mRNA from respiratory syncytial virus-infected cells. The cDNA insert was sequenced, and a protein of 27,150 daltons was deduced from the DNA sequence. The protein is relatively acidic, containing two clusters of acidic amino acids, one in the middle of the molecule and the other at the C-terminus. It is devoid of both cysteine and tryptophan. There was no other potential reading frame within the phosphoprotein gene of respiratory syncytial virus. This situation is unlike that with Sendai virus, a paramyxovirus, which has a nonstructural C protein encoded by a second overlapping reading frame near the 5' end of the mRNA for phosphoprotein.

Amino Acid Sequence↗
PubMed1983

Comparative immunofluorescence of murine leukemia virus-derived membrane-associated antigens.

We recently reported that the distribution and location of Moloney murine leukemia virus-derived membrane-associated gp70 and p30 antigens on the surface of 3.7% formaldehyde-fixed, chronically infected mouse fibroblasts were completely distinct, as judged by immunofluorescent light microscopy (M. Satake, P. N. McMillan, and R. B. Luftig (1981), Proc. Nat. Acad. Sci. USA 78, 6266). gp70, one of the two env gene products, exhibited a multiple-dot fluorescent pattern on the external surface of infected cells, while p30, one of the gag gene products, exhibited a diffuse fluorescence pattern which was apparently derived from Pr65gag molecules associated with the cytoplasmic face of the cell membrane. We have now examined the membrane fluorescence patterns of p15E, the other env gene product, as well as p15, p12, and p10, the other gag gene products. In these studies, both multivalent and monoclonal antibodies as well as fluorescein- and rhodamine-conjugated probes were used. We found that: (i) each of the env gene products, gp70 and p15E, exhibited characteristic and distinctive multiple-dot staining patterns. Further, each protein was labeled on intact cells with 125I-protein A plus homologous antiserum, confirming that both gp70 and p15E had externally exposed antigenic determinants. (ii) Among the gag gene products, p15 exhibited a different membrane fluorescence pattern than the diffuse pattern seen with p30, p12, and p10. The p15 pattern had an additional multiple-dot component. (iii) By double immunofluorescence we observed that the p15E and p15 multiple-dot patterns were superimposable at the same loci on infected cells. These three results suggest, first, that the cleavage of gp70 and p15E occurs prior to the arrival of the env polyprotein precursor at the cell surface and, second, there is an association between p15E and p15 antigenic determinants at the cell membrane. This latter association between an env and a gag gene product may be important for viral assembly.

Animals↗
PubMed1983

The cytoskeleton of murine leukemia virus (MuLV)-infected mouse fibroblasts as observed under varying conditions of formaldehyde fixation.

Mouse fibroblasts chronically infected with Moloney murine leukemia virus (MuLV) were fixed using variable amounts of formaldehyde, then examined by indirect immunofluorescence light microscopy. Several antisera were employed to detect both external and internal antigens associated with the cells, eg, MuLV gp70, tubulin, vimentin, and actin. Our results indicate that the cell membranes could be partially permeabilized to IgG molecules directed against the three cytoskeletal antigens only after 3.7%, but not 1%, formaldehyde treatment. Complete permeabilization was achieved by subsequent acetone treatment of cells after 3.7% formaldehyde fixation. In such cells, normal-appearing cytoskeletal networks of microtubules and intermediate filaments were observed. Stress fibers were also seen; however, they appeared less numerous and thinner than those of uninfected mouse fibroblasts. Further, a significant amounts of F-actin fluorescence was localized in granules in the cytoplasm of infected cells. Similar observations were made using JLS-V9 mouse cells chronically infected with 334C virus, another MuLV. These results taken together suggest that subtle differences exist in the organization of actin within MuLV-infected and uninfected mouse fibroblasts.

Actins↗
PubMed1983

Amelioration of the ultraviolet sensitivity of an Escherichia coli recA mutant in the dark by photoreactivating enzyme.

When a recA strain of Escherichia coli is transformed with a multicopy plasmid, pKY1, carrying the phr gene of E. coli, its extreme ultraviolet sensitivity is decreased. Derivatives of pKY1 were prepared in which the phr gene was inactivated by inserting transposon Tn1000. None of the 20 phr- derivatives decreased the UV sensitivity of the recA strain. In an analogous experiment, we obtained 11 derivatives which failed to decrease the UV sensitivity of the recA strain. None of them complemented phr strain. Furthermore, TN1000 insertion sites in both types of derivatives were mapped in the same region of the plasmid. From these observations, we propose that the E. coli phr gene product has repair activity in the dark.

Bacterial Proteins↗
PubMed1983

Binding characteristics of a sea anemone toxin from Parasicyonis actinostoloides with crayfish leg nerves.

A sea anemone toxin from Parasicyonis actinostoloides which inhibits the inactivation process of the sodium channel was acylated by using cold or tritium labeled propionyl N-hydroxysuccinimide ester. Acylation changed the isoelectric point of the peptide but did not change the toxicity to the crayfish nerve. Propionyl-toxin bound to leg nerves with Kd of 310 nM and Bmax of 104 pmol/g of wet nerve. The binding affinity and physiological activity of the toxin to crayfish nerves were suppressed with a common dependence on membrane depolarizations induced by elevated external K+ concentrations.

Animals↗
PubMed1983

[Immunochemical characterization of light smooth-surfaced membrane of the rat brain].

The microsomal fraction of the rat brain had been subfractionated by a sucrose density gradient centrifugation into three distinct membrane fractions, namely "light smooth-surfaced membrane" LSM, "heavy smooth-surfaced membrane" HSM, and "rough-surfaced membrane". They were different in their chemical compositions and enzymatic activities as well as their buoyant densities. In the present experiment antisera to purified LSM and HSM were raised in rabbits to characterize the two membranes immunochemically and immunohistochemically. Antigenicity of these membranes was studied by using [125I]-protein A autoradiography and immunohistochemical localization of the antigens in the rat brain was revealed by the indirect immunoperoxidase technique. By [125I]-protein A autoradiography (Fig. 1), differences in the antigenicity between LSM and HSM were clearly shown. Two out of nine antisera to LSM were relatively specific to LSM; anti-LSM #8 serum detected a protein band of Mr 53,000 which is relatively specific to LSM (Fig. 1 B-a) and anti-LSM #9 serum reacted with three proteins specific to LSM (Mr 53,000, Mr 46,000, and Mr 27,000) (Fig. 1 C-a). However, anti-HSM sera did not discriminate between LSM and HSM antigens (Fig. 1 D & E) and non-immune serum did not detect any antigen at all (Fig. 1 F). Indirect immunoperoxidase pattern by anti-LSM #8 revealed heavy staining of the neuropil in the cortices of cerebrum, hippocampus and cerebellum (Fig. 2 A, B & C). The perivascular structures identical to glial end-feet were also stained but the cell bodies and dendritic trunks of the neurons were not stained.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Microtubule-depolymerizing agents inhibit Moloney murine leukaemia virus production.

The effects of microtubule-depolymerizing agents on virion production in MJD-54 cells chronically infected with Moloney murine leukaemia virus were examined. By measuring the amount of reverse transcriptase activity remaining in particles recovered from culture fluids, we found that incubation with 1 microM- or 10 microM-colchicine, vinblastine or nocodazole resulted in 30 to 40% decreases in virus production. The decrease in virus production did not seem to be due to general damage to the cells since cellular RNA and protein synthesis were only slightly, if at all, inhibited by the drug treatment (less than 10%). Furthermore, virus proteins accumulated inside drug-treated cells, viz, [35S]methionine-labelled Pr65gag showed a 1.5-fold increase over a 3 h continuous label interval. Consistent with this accumulation of virus protein, electron microscope studies showed that inside drug-treated cells ther was a 2- to 2.5-fold accumulation of virions within cytoplasmic vesicles. All of these results support the idea that cytoplasmic microtubules play a role in the production of murine leukaemia virus.

Animals↗
PubMed1981

Increased concentration and accelerated synaptosomal uptake of noradrenaline in the central nervous tissues of neonatally hemispherectomized adult rats.

Neonatally hemispherectomized adult rat brain was analyzed. The content of noradrenaline (NA) had increased significantly in the brain stem (+ 116%) and the cerebellum (+ 100%) by the 3rd month after operation. The Km for the high affinity uptake of NA by the brain stem synaptosomes stayed unchanged but Vmax was almost doubled by the operation. Fluorescence histochemical findings also suggest sprouting of noradrenergic axons in specific brain regions.

Animals↗
PubMed1981

Acidic sphingoglycolipids in invertebrate nervous tissue: presence of several kinds of sphingophosphonoglycolipids in the nervous tissue of Aplysia kurodai, a sea gastropod.

Several hitherto unknown sphingophosphonoglycolipids were identified in the lipid extract from the nervous tissue, nerve fibers and ganglia of Aplysia kurodai, which has only a small amount of gangliosides, if any. The most abundant sphingophosphonoglycolipids of the nerve fiber (FGL-VII) and ganglion (GGL-V) are ceramide bis(2-aminoethylphosphono)-pentaosides. Their oligosaccharide moieties consist of 1 mol each of glucose, 3-O-methylgalactose and galactosamine and 2 mol of galactose. Another main glycolipid (FGL-II) may be ceramide mono(2-aminoethylphosphono)-pentaoside which contains 1 mol each of glucose, galactosamine and fucose and 2 mol of galactose as its oligosaccharide moiety.

Animals↗
PubMed1981

Reduced glycine receptor in the spinal cord in amyotrophic lateral sclerosis.

Transmitter receptor binding was estimated in the spinal cord of 6 subjects with amyotrophic lateral sclerosis (ALS) and 4 control subjects in assays using 3H-quinuclidinyl benzilate for muscarinic cholinergic receptors, 3H-strychnine for glycinergic receptors, 3H-spiroperidol for dopaminergic receptors, 3H-muscimol for GABAergic receptors, and 3H-dihydroalprenolol for beta-adrenergic receptors. In ALS, glycinergic receptor binding was greatly reduced in the anterior gray matter. This finding may be attributed to loss of large neurons in the anterior gray matter, known to be characteristic of ALS.

Adult↗
PubMed1981

Potential-dependent effects of sea anemone toxins and scorpion venom on crayfish giant axon.

Effects of two kinds of sea anemone toxin (Parasicyonis actinostoloides and Anemonia sulcata) and scorpion venom (Leiurus quinquestriatus) on crayfish giant axons were examined electrophysiologically. All toxins acted on the axon in a similar manner to prolong the falling phase of the action potential. In all cases the development of toxicity was reduced when the nerve membrane was depolarized by a current injection. However, the ranges of membrane potential where the significant reduction in toxicity took place were different for each toxin. The action of Parasicyonis toxin was also suppressed by depolarization resulting from treatment of the axon with a neurotoxic alkaloid, veratridine. The mechanism of the potential-dependent toxin action is discussed with reference to the present data and relevant works by other investigators.

Animals↗