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Biomedical subjects

N Tominaga

Publications and source records attributed to N Tominaga.

At least 73 records · Page 4Linked to original sources
PubMed1986

Intracellular molecular species of human chorionic gonadotropin from normal but non-cultured first trimester placental tissues.

Intracellular forms of human chorionic gonadotropin (hCG) were analyzed by SDS-polyacrylamide gel electrophoresis, protein blotting and immunological techniques in normal but non-cultured first trimester placentae. Placental cells were found to contain the major components of the 23K and 19K forms of the beta-subunit and the 21K form of the alpha-subunit of hCG which remained sensitive to endoglycosidase H and Con A-Sepharose 4B and small amounts of mature (urinary) subunits. An unknown molecular species of the alpha-subunit (Mr = 17K) that was not bound to Con A-Sepharose 4B was also detected. These intracellular molecular species accumulated in the placentae mainly during the first trimester. These results suggest that hCG subunits accumulate in placental cells as predominant intermediates containing high-mannose oligosaccharides.

Chorionic Gonadotropin↗
PubMed1986

Isolation and characterization of proteinases from the sarcocarp of snake-gourd fruit.

Seven proteinases were isolated from the fruit of snake-gourd, Trichosanthes cucumeroides Maxim. Their isozymes are all serine proteinases, and homologous in their respective molecular weights, amino acid compositions, and enzymatic properties. Their molecular weight was estimated to be about 50,000. Using casein as a substrate, the maximum activity was found in the alkaline pH region. The optimum temperature using casein was 70 degrees C at pH 7.3. The enzymes were strongly inhibited by diisopropyl fluorophosphate and not inhibited by inhibitors of sulfhydryl or metalloproteases. The reduced and S-carboxymethylated insulin B-chain was used as a substrate in an investigation of the specificity. The enzyme was found to have a wide specificity for this substrate but preferentially hydrolyzed the peptide bonds involving the carboxyl groups of charged amino acid such as S-cm-cysteine, glutamic acid, histidine, arginine, and lysine. Experimental evidence indicated that the snake-gourd proteinases are similar in their properties to cucumisin, which is isolated from the sarcocarp of melon fruit.

Amino Acids↗
PubMed1986

Endotoxin level of sterile injection solutions and substitution fluid for hemofiltration in Japan and Australia.

The endotoxin contamination levels of sterile distilled water and saline solutions used for injection and hemofiltration in Japan and Australia were examined with a colorimetric limulus test using a chromogenic substrate. The endotoxin levels of injection solutions in most products from both countries measured against E. coli 0111:B4 endotoxin or USP reference standard endotoxin were less than 0.2 pg or 0.0006 endotoxin units (EU) X ml-1. Only 2 solutions in 30 from both countries showed higher levels: 7.7 and 10.8 pg for E. coli 0111:B4 endotoxin X ml-1 (0.02 and 0.03 EU X ml-1). Even these higher values were well below the level recommended by the draft guideline published by the United States Food and Drug Administration (FDA). The endotoxin contamination level of a Japanese hemofiltration substitution fluid ranged from 8.2 to 9.2 pg E. coli 0111:B4 endotoxin X ml-1 (0.024-0.027 EU X ml-1).

Australia↗
PubMed1986

Aspergillus vegetative endocarditis complicated with schizocytic hemolytic anemia in a patient with acute lymphocytic leukemia.

Aspergillus vegetative endocarditis developing in a patient with acute lymphocytic leukemia during the phase of hematological remission has led to a fatal outcome, complicated with severe hemolytic anemia with red cell fragmentation. Systemic aspergillosis may involve heart valves with underlying disorders, but seldom affects intact valves even in severely compromised hosts. Among such rare cases so far reported, only 2 cases have been documented in acute leukemia, despite a huge prevalence of pulmonary and systemic aspergillosis in hematological malignancies. Our present case is essentially the same as in the preceding two cases in that endocarditis occurred during the hematological remission. These clinical, observations may suggest that every leukemic patient suffering from aspergillosis is susceptible to the valvular complication after, rather than during, the period of severe myelosuppression, because platelets play an important role in the formation of thrombotic lesions.

Anemia, Hemolytic↗
PubMed1985

Isolation, primary structure and synthesis of heat-stable enterotoxin produced by Yersinia enterocolitica.

Five heat-stable enterotoxins were isolated from the culture supernatant of Yersinia enterocolitica and purified to homogeneity by DEAE-Sephacel and high-performance liquid chromatographies. They caused acute fluid accumulation in the intestine of suckling mice. The amino acid sequence of one of the enterotoxins was determined to be Ser-Ser-Asp-Trp-Asp-Cys-Cys-Asp-Val-Cys-Cys-Asn-Pro-Ala-Cys-Ala-Gly-Cys, by Edman degradation of its pyridylethylated derivative and a combination of fast atom bombardment mass spectrometry and carboxypeptidase B digestion. This structure was unambiguously confirmed by chemical synthesis. The other enterotoxins had longer or shorter amino acid sequences at their N termini, but the same sequence at their C termini. The six half-cystine residues formed intramolecular disulfide linkages, as shown by measurement of the molecular masses of the enterotoxins by fast atom bombardment mass spectrometry. The sequence of 13 amino acid residues at the C terminus showed similarity to those of heat-stable enterotoxins isolated from enterotoxigenic Escherichia coli [Aimoto, S. et al. (1982) Eur. J. Biochem. 129, 257-263; Takao, T. et al. (1983) FEBS Lett. 152, 1-5] suggesting that these similar sequences are related to the common biological and immunological properties of enterotoxins produced by Y. enterocolitica and enterotoxigenic E. coli.

Amino Acid Sequence↗
PubMed1984

Primary structure of heat-stable enterotoxin produced by Yersinia enterocolitica.

A heat-stable enterotoxin was isolated and purified from the culture supernatant of Yersinia enterocolitica by reversed-phase high-performance liquid chromatography. The amino acid sequence of the purified toxin was determined to be as follows: (sequence; see text) (X: not determined). The C-terminal sequence containing 6 half-cystine residues was highly homologous to that of heat-stable enterotoxin of enterotoxigenic Escherichia coli.

Amino Acid Sequence↗
PubMed1984

Amino acid sequence around the reactive serine of cucumisin from melon fruit.

Cucumisin is a diisopropyl fluorophosphate-sensitive enzyme. The inactivation by DFP is accompanied by the formation of 1 mol of labeled serine residue per mol of enzyme. From the soluble portion of the chymotryptic digest of the diisopropyl phosphoryl derivative of cucumisin, two peptides containing phosphorus were isolated; their amino acid sequences were determined to be Gly-Thr-Ser(P)-Met and Asn-Ile-Ile-Ser-Gly-Thr-Ser(P)-Met, respectively. The four residues Gly-Thr-Ser-Met in the above amino acid sequence are identical with those of subtilisin.

Amino Acid Sequence↗
PubMed1983

Studies of peptide antibiotics. XLIV. Syntheses and biological activities of gramicidin S analogs containing delta-hydroxy-L-norvaline or glycine.

The antibiotic gramicidin S (GS) has the structure of cyclo (-L-Val1-L-Orn2-L-Leu3-D-Phe4-L-Pro5-L-Val1'-L-Orn2'-L-Leu3'-D-Phe4'-L-Pro5'-) and is basic in character. Five GS analogs including [Gly1,1']-GS and the neutral [L-Hnv2,2']-GS (Hnv represents delta-hydroxynorvaline) were synthesized by the solid-phase method to evaluate the role of L-Val1,1' and L-Orn2,2' residues in GS. The hybrid analogs [( Gly1]-GS and [L-Hnv2]-GS) and [D-Tyr4,4']-GS showed high antibacterial activities, whereas [Gly1,1']-GS and [L-Hnv2,2']-GS possessed no activity. Inhibitory effects by these analogs for the adsorption of 14C-labeled GS on cells of bacteria sensitive to GS were determined. The structure-activity relationship of GS is discussed on the basis of the results on these GS analogs.

Amino Acid Sequence↗
PubMed1981

Adsorption of 14C-labeled gramicidin S on cell of bacteria.

Gramicidin S (GS) containing 14C-labeled proline was synthesized by a solid-phase method, and the labeled GS dihydrochloride was obtained as crystals. The labeled GS exhibited same antibacterial activity as natural GS. Strains sensitive to GS (B. subtilis and S. aureus) and an insensitive strain (E. coli) were treated with the labeled GS, and the amount of the labeled GS adsorbed on the cells was measured. GS was adsorbed rapidly on the cells of the sensitive strains; the amount adsorbed increased linearly with GS concentration up to 1-1.5 microgram/ml, and at a lower rate at above 1.5 microgram/ml. GS molecules covered most of the cell surface at the minimum inhibitory concentration of 1.5 microgram/ml; the number of molecules adsorbed per cell was 1.3-1.4 x 10(6). No GS was adsorbed by the insensitive strain.

Adsorption↗
PubMed1977

Purificantion and characterization of inorganic pyrophosphatase from Thiobacillus thiooxidans.

An inorganic pyrophosphatase [EC 3.6.1.1] was isolated from Thiobacillus thiooxidans and purified 975-fold to a state of apparent homogeneity. The enzyme catalyzed the hydrolysis of inorganic pyrophosphate and no activity was found with a variety of other phosphate esters. The cation Mg2+ was required for maximum activity; Co2+ and Mn2+ supported 25 per cent and 10.6 per cent of the activity with Mg2+, respectively. The pH optimum was 8.8. The molecular weight was estimated to be 88,000 by gel filtration and SDS gel electrophoresis, and the enzyme consisted of four identical subunits. The isoelectric point was found to be 5.05. The enzyme was exceptionally heat-stable in the presence of 0.01 M Mg2+.

Acidithiobacillus thiooxidans↗
PubMed1975

Isolation and characterization of a proteinase from the sarcocarp of melon fruit.

A proteinase from the sarcocarp of melon (Cucumis Melo L. var. Prince) was purified by a three-step procedure involving batch-wise treatment with CM-cellulose fibers, column chromatography on CM-cellulose powder and gel filtration on Sephadex G-75. The final enzyme preparation was homogeneous on acrylamide gel electrophoresis. Its molecular weight was estimated by two different methods to be about 50,000. Anlayses indicated tha presence of 475 amino acid residues and at least 7 moles of hexose. The maximum activity was found in the alkaline pH region against casein as a substrate. The optimum temperature against casein was 70 degrees at pH 7.1. The enzyme was strongly inhibited by diisopropyl fluorophosphate, partly inhibited by HgCl2 and not inhibited by EDTA, p-chloromercuribenzoic acid, N-tosyl-L-lysine chloromethyl ketone, N-tosyl-L-phenylalanine chloromethyl ketone, and soybean trypsin inhibitor. The reduced and carboxymethylated insulin B-chain was cleaved at the peptide bonds of Asn3-Gln4, Cm-Cys7-Gly8, Glu13-Ala14, Leu15-Tyr16, Cm-Cys19-Gly20, Phe25-Tyr26, Pro28-Lys29, and Lys29-Ala30 by the enzyme.

Amino Acids↗