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Biomedical subjects

M Inukai

Publications and source records attributed to M Inukai.

At least 37 records · Page 2Linked to original sources
PubMed1993

Screening method for colony-stimulating factor inducers using a human bone marrow stromal cell line, KM-102.

A new screening method for inducers of colony-stimulating factors (CSFs) was established using KM-102, a human bone marrow stromal cell line as the producer. In this method, the assay system which uses CSF dependent cell lines is combined with the CSF production system. Interleukin-1 (IL-1), which is known to upregulate CSF production in many cell populations, was used as a positive control for production of granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF). Induction in the positive controls was clearly detected within 24 hours. Activators of protein kinase C (PKC), protein phosphatase inhibitors and lipopolysaccharide (LPS) were positive in this assay system, but muramyl dipeptide (MDP) and Bestatin which are known macrophage activators, were negative. Inducers of CSFs were successfully detected using this assay method. Among 1,600 microbial strains tested, 2 actinomycete strains were found to produce active substances. One strain produces teleocidin-A, a strong activator of PKC, and the other strain produces a mixture of active compounds including three novel compounds. These three compounds do not induce terminal differentiation of HL-60 cells, suggesting that they are not teleocidin-like substances and form a new class of CSF inducers.

Bone Marrow↗
PubMed1993

Novel microbial metabolites of the phoslactomycins family induce production of colony-stimulating factors by bone marrow stromal cells. I. Taxonomy, fermentation and biological properties.

Three metabolites were isolated from the culture broth of an actinomycete strain identified as Streptomyces platensis SANK 60191, that induce the production of colony-stimulating factors (CSFs) by stromal cell line KM-102 at ED50 concentrations from 40 to 200 ng/ml. The compounds induced quantities of granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF) comparable to those induced by interleukin-1, a strong CSF inducer. These metabolites were called leustroducsins (A, B and C) and were later found to be structurally related to phoslactomycins. This is the first report of CSF inducing activity by members of the phoslactomycin class.

Antifungal Agents↗
PubMed1992

Susceptibility of Pseudomonas species to the novel antibiotics mureidomycins.

Strains of Pseudomonas aeruginosa, including imipenem- or ofloxacin-resistant clinical isolates, and some other species in the genus Pseudomonas were inhibited by novel antibiotics of the mureidomycin (MRD) group. On the other hand, almost all other gram-positive and gram-negative bacteria were resistant to MRDs, though the antibiotics potently inhibited the in vitro peptidoglycan synthesis of Escherichia coli and P. aeruginosa. All of the strains in the genus Pseudomonas that were inhibited by less than or equal to 200 micrograms of MRDs per ml were classified into the rRNA groups I and III, and none of the tested strains of rRNA group I were resistant to MRDs, suggesting that these two groups are closely related to each other evolutionary. Among group I strains, P. aeruginosa, P. mendocina, P. stutzeri, and P. alcaligenes were more susceptible than the others, suggesting a closer relationship among these species.

Anti-Bacterial Agents↗
PubMed1992

Galacardins A and B, new glycopeptide antibiotics.

A strain of actinomycetes identified as Saccharothrix sp. SANK 64289 was found to produce new antibiotics, galacardins A and B. Their physico-chemical properties showed that they were new members of glycopeptide antibiotics. They were structurally related to beta-avoparcin but differed from it only in sugar composition. Though beta-avoparcin does not contain galactose, galacardins A and B did contain two and one moles of galactose, respectively. They showed strong antimicrobial activity against Gram-positive bacteria and also showed excellent in vivo protective activity against Staphylococcus aureus infection in mice.

Actinomycetales↗
PubMed1991

Mureidomycin A, a new inhibitor of bacterial peptidoglycan synthesis.

Mureidomycin A (MRD), a novel peptidylnucleoside antibiotic with antipseudomonal activity, inhibited not only peptidoglycan synthesis but also lipid-intermediate formation from UDP-N-acetylmuramyl (MurNAc)-pentapeptide and UDP-N-acetylglucosamine in an in vitro peptidoglycan-synthesizing system, using ether-treated cells of Pseudomonas aeruginosa. Both types of inhibition by MRD disappeared when UDP-MurNAc-pentapeptide was preincubated with ether-treated cells. Moreover, MRD completely inhibited lipid-intermediate I (undecaprenyl-p-p-MurNAc-pentapeptide) formation at a concentration below the MIC. From these results, it was concluded that the real target of MRD's action was translocase, which catalyzes lipid-intermediate I formation from UDP-MurNAc-pentapeptide and a lipid carrier.

Anti-Bacterial Agents↗
PubMed1991

Helvecardins A and B, novel glycopeptide antibiotics. I. Taxonomy, fermentation, isolation and physico-chemical properties.

A strain of actinomycetes identified as Pseudonocardia compacta subsp. helvetica produced new glycopeptide antibiotics, helvecardins A and B. They were isolated from culture broth mainly by affinity chromatography of D-alanyl-D-alanine and preparative HPLC. The physico-chemical properties of helvecardins A and B showed that they resemble each other. Though helvecardin A was structurally related to beta-avoparcin, it clearly differed in the presence of an O-methyl moiety in its NMR spectrum.

Aminoglycosides↗
PubMed1991

Helvecardins A and B, novel glycopeptide antibiotics. II. Structural elucidation.

Helvecardins A and B, which are produced by Pseudonocardia compacta subsp. helvetica, are new members of glycopeptide antibiotics. They contain the same pseudoaglycone as beta-avoparcin and the same compositions of neutral sugar, amino sugar, and amino acid except that 2'-O-methylrhamnose was detected in helvecardins instead of rhamnose in beta-avoparcin, and mannose was not detected in helvecardin B. From these results and 1H NMR and mass spectral analyses, helvecardins A and B were determined beta-avoparcin 2'-O-methylated on rhamnose and demanosylhelvecardin A, respectively.

Aminoglycosides↗
PubMed1991

Helvecardins A and B, novel glycopeptide antibiotics. III. Biological properties.

Helvecardins (HVCs) A and B were strongly active against aerobic and anaerobic Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), but they were inactive against Gram-negative bacteria and fungi. Though HVC A showed only slightly stronger antimicrobial activity than beta-avoparcin (AVP), its in vivo protective activity against S. aureus infection in mice was greatly superior to AVP.

Aminoglycosides↗
PubMed1989

Fosfonochlorin, a new antibiotic with spheroplast forming activity.

A new antibiotic, fosfonochlorin, was found in the culture filtrate of four strains of fungi freshly isolated from soil samples. These strains were identified as Fusarium avenaceum, Fusarium oxysporum, Fusarium tricinctum and Talaromyces flavus. Fosfonochlorin was a low molecular weight antibiotic (MW 158), soluble in water and methanol, but insoluble in acetone, ethyl acetate and chloroform. It was named after its possession of phosphorus and chlorine atoms, each one molar in its structure. The structure was determined as chloroacetylphosphonic acid mainly by the 1H NMR and mass spectrometric analyses. It was moderately active against some species of Gram-negative bacteria and its synergistic effect with glucose-6-phosphate was observed on Staphylococcus aureus and Escherichia coli. Spheroplast formation of the susceptible organisms with this antibiotic suggested that it might inhibit their cell wall synthesis.

Anti-Bacterial Agents↗
PubMed1989

Mureidomycins A-D, novel peptidylnucleoside antibiotics with spheroplast forming activity. I. Taxonomy, fermentation, isolation and physico-chemical properties.

A strain of actinomycetes identified as Streptomyces flavidovirens produced new antibiotics, mureidomycins (MRD's) A approximately D, specifically active against Pseudomonas aeruginosa. They were isolated from the culture filtrate by successive column chromatographies such as Amberlite XAD-2 and CG-50, Whatman DE-52 and Toyopearl HW-40. They were amphoteric white powders and soluble in methanol and water. Their molecular weights and molecular formulae in parentheses were 840 (C38H48N8O12S), 842 (C38H50N12S), 897 (C40H51N9O13S) and 899 (C40H53N9O13S), respectively. m-Tyrosine and two unknown substances were detected by amino acid analyses as their common constituents. MRD's A and C contained uracil but MRD's B and D dihydrouracil instead of uracil.

Amino Acids↗
PubMed1989

Mureidomycins A-D, novel peptidylnucleoside antibiotics with spheroplast forming activity. II. Structural elucidation.

Structures of new antibiotics, mureidomycins (MRD's) A approximately D, were deduced from spectroscopic analyses and degradation studies. Two residues of m-tyrosine, one residue of 2-amino-3-N-methylaminobutyric acid (AMBA) and methionine are present in all components of the complex. Uracil is contained in MRD's A and C, while dihydrouracil in MRD's B and D. Methionine and m-tyrosine are connected through an ureido bond, and uracil or dihydrouracil is linked to AMBA via enamine sugar moiety. In addition, MRD's C and D contain a glycine residue at the N-terminal.

Amino Acids↗
PubMed1989

Mureidomycins A-D, novel peptidylnucleoside antibiotics with spheroplast forming activity. III. Biological properties.

Mureidomycins (MRD's) A-D were specifically active against Pseudomonas aeruginosa. Among them, MRD C was most active, with MICs of 0.1 to 3.13 micrograms/ml against many strains of the target organism. Its activity was comparable to that of cefoperazone, ceftazidime and cefsulodin. MRD C-resistant mutants of P. aeruginosa appeared spontaneously at a high frequency when cultured in the presence of the antibiotic. No cross-resistance was observed with beta-lactam antibiotics. A rapid decrease of turbidity along with spheroplast formation and cell lysis was observed when cells of P. aeruginosa were grown in the presence of MRD C. The compounds exhibited low toxicity and protected mice from experimental infection with P. aeruginosa. The urinary and fecal recoveries of MRD C given subcutaneously were 5 and 18%, respectively.

Animals↗
PubMed1985

Dual functions of the signal peptide in protein transfer across the membrane.

Most secretory proteins in both prokaryotic and eukaryotic cells are synthesized from a precursor with an amino-terminal extension of 20 to 25 amino acid residues called a signal peptide. These signal peptides are removed during translocation of the secretory proteins across the membrane. When two precursor structures are fused, the internalized second signal peptide was found to exert two different roles, depending upon either the distance between the two signal peptides, or whether the first signal peptide functions cotranslationally or posttranslationally. One role is to function as the usual signal peptide to translocate the protein downstream of the internal signal peptide. The other role is to function as a stop-transfer signal to create a transmembrane protein with the second signal peptide anchoring the protein in the membrane.

Bacterial Outer Membrane Proteins↗
PubMed1984

Apolipoprotein, an intermediate in the processing of the major lipoprotein of the Escherichia coli outer membrane.

A new intermediate (apolipoprotein) in the synthesis of the major lipoprotein of the Escherichia coli outer membrane has been identified. The accumulation of this new form of the lipoprotein was observed when excessive production of lipoprotein was induced or when the membrane fraction containing the prolipoprotein accumulated in the presence of globomycin was incubated at 60 degrees C. The new form of the lipoprotein could be chased into the mature lipoprotein. In addition, from sequential analysis of this new protein by Edman degradation, the NH2 terminus was found to be cysteine, containing a free unmodified amino group and a glyceride-modified sulfhydryl group. These results indicate that this protein is an intermediate in the conversion of glyceride-modified prolipoprotein to the mature lipoprotein. It is believed that the lipoprotein signal peptidase directly cleaves the lipoprotein signal peptide at the peptide bond between the glycine residue at position 20 and the cysteine residue at position 21 of the prolipoprotein. The resulting intermediate, designated here as apolipoprotein, is subsequently acylated at its free amino group to yield the final mature lipoprotein.

Amino Acid Sequence↗
PubMed1983

Association of the prolipoprotein accumulated in the presence of globomycin with the outer membrane of Escherichia coli.

The prolipoprotein, a secretory precursor of the outer membrane lipoprotein of Escherichia coli, is known to be accumulated in the cell envelope when cells are grown in the presence of a cyclic antibiotic, globomycin. The prolipoprotein was localized in the cytoplasmic membrane when it was separated from the outer membrane by sucrose-density gradient centrifugation. However, when the envelope fraction was treated with sodium sarcosinate, the prolipoprotein was found almost exclusively in the sarcosinate-insoluble outer membrane fraction. The prolipoprotein separated in the cytoplasmic membrane by sucrose-density gradient centrifugation was soluble in sarcosinate and could not form a complex with the outer membrane once solubilized in sarcosinate. Labeling of the two lysine residues at positions 2 and 5 of the prolipoprotein with [3H]dinitrophenylfluorobenzene was enhanced 26-fold when the cells were disrupted by sonication. On the other hand, a tryptic fragment of the ompA protein, which is known to exist in the periplasmic space, increased its susceptibility to [3H]dinitrophenylfluorobenzene only 5.3-times upon disruption of the cell structure. These results indicate that the prolipoprotein accumulated in the presence of globomycin is translocated across the cytoplasmic membrane and interacts with the outer membrane. At the same time, it is attached to the cytoplasmic membrane with its amino-terminal signal peptide in such a way that the amino-terminal portion of the signal peptide containing two lysine residues is left inside the cytoplasm.

Anti-Bacterial Agents↗
PubMed1983

Effects of inserting eight amino acid residues into the major lipoprotein on its assembly in the outer membrane of Escherichia coli.

A DNA sequence consisting of 24 base pairs was inserted into the structural gene (lpp) coding for the major lipoprotein of the Escherichia coli outer membrane which was carried on a high-copy-number plasmid in which expression was regulated through a lac promoter-operator region. This modification resulted in the insertion of eight amino acid residues, Glu-Glu-Phe-Leu-Glu-Glu-Phe-Leu, between the glutamine residue at position 9 and the leucine residue at position 10 of the wild-type lipoprotein sequence. When production of the mutant lipoprotein was induced by a lac inducer, the cells became swollen, showed unusual morphology, and eventually lysed. When the membrane fraction was analyzed after the induction, the mutant lipoprotein was found to have been normally secreted across the cytoplasmic membrane and assembled in the outer membrane. This lipoprotein was modified with glycerol and palmitic acid and even formed the bound form, which was linked covalently to peptidoglycan. The major difference between the membrane-associated mutant lipoprotein and the wild-type lipoprotein was that the mutant lipoprotein became sensitive to trypsin treatment. These results indicate that the substantial alteration in mutant lipoprotein structure near the amino-terminal end does not interfere with modification of the amino-terminal cysteine residue or cleavage of the signal peptide by the prolipoprotein-specific signal peptidase. However, this mutant lipoprotein assembled in the outer membrane appears to have deleterious effects with respect to envelope structure and cellular morphology and viability.

Amino Acid Sequence↗