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K Kitamoto

Publications and source records attributed to K Kitamoto.

At least 91 records · Page 5Linked to original sources
PubMed1991

The glucoamylase cDNA from Aspergillus oryzae: its cloning, nucleotide sequence, and expression in Saccharomyces cerevisiae.

A cDNA for Aspergillus oryzae glucoamylase was cloned, using oligodeoxyribonucleotide probes derived from amino sequences of peptide fragments of the enzyme. The glucoamylase cDNA, when introduced into Saccharomyces cerevisiae, directed the secretion of active glucoamylase into the culture medium. The complete nucleotide sequence of the cDNA contained an open reading frame encoding 612 amino acid residues. Comparative studies with other fungal glucoamylases showed homologies of 67% with A. niger and 30% with Rhizopus oryzae of the deduced amino acid sequences. In the five conserved regions reported in other fungal glucoamylases, the levels of homologies between those regions of A. oryzae and A. niger enzymes were much higher (78-94%). A. oryzae glucoamylase contained no peptide region abundant in threonine and serine residue (TS-region), like that proposed to adsorb onto raw starch in A. awamori var. kawachii glucoamylase.

Amino Acid Sequence↗
PubMed1991

[A case of anti-myeloperoxidase antibodies-associated idiopathic crescentic glomerulonephritis with pulmonary hemorrhage].

We report a case of idiopathic crescentic glomerulonephritis with pulmonary hemorrhage associated with anti-myeloperoxidase antibodies (anti-MPO ab). A 74 year-old female was admitted to our hospital because of rapidly progressive glomerulonephritic syndrome and dyspnea with bloody sputum. On admission anti-MPO ab, one of anti-neutrophil cytoplasmic antibodies, were detected but anti-GBM antibodies and immune complexes were not detected. Renal biopsy showed crescentic glomerulonephritis and lung biopsy showed massive alveolar hemorrhage. Both tissue had pauci-immune deposit by immunofluorescence microscopy. Hemodialysis and steroid administration were started. Pulmonary hemorrhage was improved remarkably, but renal failure progressed rapidly to end stage kidney, then hemodialysis was continued. Although subsequent 3 years uneventful maintenance hemodialysis had been performed, she admitted to our hospital again because of progressive dyspnea with hemoptysis after upper respiratory tract infection. On admission anti-MPO ab were detected again and steroid administration was started. Pulmonary hemorrhage was improved with decreased anti-MPO ab titer. While tapering the dosis of steroid, anti-MPO ab again increased and pulmonary hemorrhage recurred. Although pulse methylprednisolone therapy and plasma exchange were performed, respiratory failure progressed rapidly and she died of sepsis. Postmortem examination showed no evidence of systemic vasculitis. In this case, titer of anti-MPO ab was associated with not only idiopathic crescentic glomerulonephritis but also with pulmonary hemorrhage. We tried to detect enzymatically active MPO in serum. Titer of serum MPO was also associated with disease activity and anti-MPO ab. It is suggested that both anti-MPO ab and serum MPO are closely related to the pathogenesis of idiopathic crescentic glomerulonephritis and pulmonary hemorrhage.

Aged↗
PubMed1990

The SLP1 gene of Saccharomyces cerevisiae is essential for vacuolar morphogenesis and function.

The SLP1 gene, which is involved in the expression of vacuolar functions in the yeast Saccharomyces cerevisiae (K. Kitamoto, K. Yoshizawa, Y. Ohsumi, and Y. Anraku, J. Bacteriol. 170:2687-2691, 1988), has been cloned from a yeast genomic library by complementation of the slp1-1 mutation. The isolated plasmid has a 7.8-kilobase BamHI-BamHI fragment that is sufficient to complement several characteristic phenotypes of the slp1-1 mutation. The fragment was integrated at the chromosomal SLP1 locus, indicating that it contains an authentic SLP1 gene. By DNA sequencing of the SLP1 gene, an open reading frame of 2,073 base pairs coding for a polypeptide of 691 amino acid residues (Mr, 79,270) was found. Gene disruption of the chromosomal SLP1 did not cause a lethal event. Vacuolar proteins in the delta slp1 mutant are not processed to vacuolar forms but remain in Golgi-modified forms. Carboxypeptidase Y in the delta slp1 mutant is localized mainly to the outsides of the cells. delta slp1 mutant cells have no prominent vacuolar structures but contain numerous vesicles in the cytoplasm, as seen by electron microscopy. Genetic and molecular biological analyses revealed that SLP1 is identical to VPS33, which is required for vacuolar protein sorting as reported by Robinson et al. (J. S. Robinson, D. J. Klionsky, L. M. Banta, and S. D. Emr, Mol. Cell. Biol. 8:4936-4948, 1988). These results indicate that the SLP1 (VPS33) gene is involved in the sorting of vacuolar proteins from the Golgi apparatus and their targeting to the vacuole and that it is required for the morphogenesis of vacuoles and subsequent expression of vacuolar functions.

Amino Acid Sequence↗
PubMed1990

[Morphologic transformation of renal lesions by steroid treatment and its therapeutic implication in a patient with lupus nephritis].

When we perform renal biopsy in patients with lupus nephritis (LN), we use the histopathological findings in glomerulus for the choice and dosage of steroid and immunosuppressive therapy. Recently, we experienced a case of LN who underwent three times of renal biopsy and had received various dosages of steroid. Our therapy resulted in her renal function deteriorated over 5 years. In detail, the patient was a 45-year-old female and the first renal biopsy was performed at the active stage of LN with nephrotic syndrome and serological activities. The biopsy specimen showed membranous LN accompanied by mesangial proliferation, necrosis, cellular crescents and intramembranous deposits. Thus, large dose of steroid including pulse therapy was given, and subsequently massive proteinuria and serological activities subsided gradually. However, 4.0 g of proteinuria per day remained in the patient. Accordingly, the second biopsy was done at one and half years later and it showed the regression to nearly pure membranous LN with thickening of glomerular basement membrane and only mild increment of mesangial matrix. Thus, she remained on 15 mg of daily prednisolone. Eventually, she progressed to 2.3 mg/dl of serum creatinine in renal function. The third biopsy was undertaken 5 years later and it showed sclerosing LN with tubular atrophy. Based upon these serial morphologic alterations in LN, we presumed that steroid treatment per se was not adequate for the control of this type of LN and new additional therapy including cytotoxic drugs is probably needed for the improvement of these glomerular lesions.

Biopsy↗
PubMed1990

[High sensitive photometric assay of pancreatic lipase and clinical investigation of urinary lipase in patients with various histopathological types of primary glomerulonephritis].

We measured the activity of urinary lipase by high sensitive photometric method using 1,2-dirinoleoilglycerol as a substrate. Also, we investigated the clinical significance of the activity of urinary lipase in patients with chronic glomerulonephritis (GN) with special reference to the relation between the levels of the enzyme and histopathological changes of the kidney. Urinary activity of N-acetyl-beta-D-glucosaminidase (NAG) and urinary beta 2-microglobulin (BMG) were also measured to compare the difference of renal handling of these 3 substances. We could obtain the following results; 1) Good coefficient of correlation was observed between the activity of urinary lipase and the excretion of urinary BMG. 2) No correlation was observed between the activity of urinary lipase and the amount of urinary NAG in patients with chronic GN. 3) In some of the cases with secondary tubulointerstitial edema and inflammatory infiltration, the values of the activity of urinary lipase were markedly elevated. These results suggested that lipase was removed from the serum mainly by glomerular filtration and reabsorbed almost completely by tubular epithelial cells like the renal handling of BMG. In contrast, NAG secreted through the different renal metabolism in proximal tubule. The activity of urinary lipase might be a diagnostic marker for the secondary acute tubulointerstitial lesions in patients with chronic GN.

Acetylglucosaminidase↗
PubMed1989

[Clinical investigation of urinary activity of NAG and AAP in patients with various types of primary glomerulonephritis].

We investigated the activity of NAG and AAP in the urine of 36 patients with chronic glomerulonephritis (GN) with special reference to the relation between the levels of the enzymes and histopathological changes of the kidney. The subjects consist of 7 cases of minimal change nephrotic syndrome (MCNS), 3 cases of membranous GN, 5 cases of IgA. GN, 5 cases of membranoproliferative GN, 3 cases of focal glomerulosclerosis and 12 cases of chronic renal failure who had creatinine levels of more than 2 mg/dl resulting from chronic GN. Urinary levels of NAG and AAP were significantly higher in cases with GN than those in cases with chronic renal failure. In cases with GN, urinary levels of NAG and AAP correlated with the amounts of urinary protein, while those levels had no correlation with the classification of histopathological changes of glomeruli. The high value of NAG/mg.protein ratio, NAG by urinary protein, might be explained by the degree of tublointerstitial damage. We concluded that urinary levels of NAG and AAP reflects the proximal tubular damage caused by protein reabsorption.

Acetylglucosaminidase↗
PubMed1989

[Therapeutic effects and influence on the urinary enzyme activity of human urinary trypsin inhibitor (urinastatin) in cases with acute renal failure--changes in the urinary activities of NAG and AAP].

We studied the therapeutic effects of human urinary trypsin inhibitor (UTI) in 5 cases with acute renal failure, resulting from traumatic shock in 1 case, post-operative shock in 2 cases, septic shock in 1 case, and dehydration in 1 case. We administered 300,000 u/day of UTI intravenously at the initial phase of acute renal failure for 7 days. We measured the activities of urinary N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase (AAP) and the activities of serum beta-glucuronidase, PMN-elastase serially. As a control, we also studied same markers in 5 cases with acute renal failure without the administration of UTI. We could obtain the following results. 1) Urinary activities of NAG and AAP were already elevated markedly at the onset phase of acute renal failure. 2) The administration of UTI caused a significant decrease of the activities of NAG and AAP in the urine as compared with those in the controls. 3) The administration of UTI caused also the significant suppression of the activities of beta-glucuronidase and PMN-elastase in the serum. These results suggested that UTI has the protective effects on the tubular epithelial cell injuries in cases of acute renal failure.

Acetylglucosaminidase↗
PubMed1988

Changes induced in the permeability barrier of the yeast plasma membrane by cupric ion.

A specific effect of Cu2+ eliciting selective changes in the permeability of intact Saccharomyces cerevisiae cells is described. When 100 microM CuCl2 was added to a cell suspension in a buffer of low ionic strength, the permeability barrier of the plasma membranes of the cells was lost within 2 min at 25 degrees C. The release of amino acids was partial, and the composition of the amino acids released was different from that of those retained in the cells. Mostly glutamate was released, but arginine was mainly retained in the cells. Cellular K+ was released rapidly after CuCl2 addition, but 30% of the total K+ was retained in the cells. These and other observations suggested that Cu2+ caused selective lesions of the permeability barrier of the plasma membrane but did not affect the permeability of the vacuolar membrane. These selective changes were not induced by the other divalent cations tested. A novel and simple method for differential extraction of vacuolar and cytosolic amino acid pools by Cu2+ treatment was established. When Ca2+ was added to Cu2+-treated cells, a large amount of Ca2+ was sequestered into vacuoles, with formation of an inclusion of a Ca2+-polyphosphate complex in the vacuoles. Cu2+-treated cells also showed enhanced uptake of basic amino acids and S-adenosylmethionine. The transport of these substrates showed saturable kinetics with low affinities, reflecting the vacuolar transport process in situ. With Cu2+ treatment, selective leakage of K+ from the cytosolic compartment appears to create a large concentration gradient of K+ across the vacuolar membrane and generates an inside-negative membrane potential, which may provide a driving force of uptake of positively charged substances into vacuoles. Cu2+ treatment provides a useful in situ method for investigating the mechanisms of differential solute pool formation and specific transport phenomena across the vacuolar membrane.

Amino Acids↗
PubMed1988

Dynamic aspects of vacuolar and cytosolic amino acid pools of Saccharomyces cerevisiae.

By using the Cu2+ method (Y. Ohsumi, K. Kitamoto, and Y. Anraku, J. Bacteriol. 170:2676-2682, 1988) for differential extraction of the vacuolar and cytosolic amino acid pools from yeast cells, the amino acid compositions of the two pools extracted from Saccharomyces cerevisiae cells, grown in synthetic medium supplemented with various amino acids, were determined. Histidine and lysine in the medium expanded the vacuolar pool extremely. Glutamate also accumulated in the cells, but mainly in the cytosol. The composition of amino acids in the cytosolic pool was fairly constant, in contrast to that in the vacuolar pool. Cells grown in synthetic medium supplemented with 10 mM arginine accumulated arginine in the vacuoles at a concentration of about 430 mM. This large arginine pool was metabolically active and was effectively utilized during nitrogen starvation. Arginine efflux from the vacuoles was coupled with K+ influx, with an arginine/K+ exchange ratio of 1, as judged by the initial rate. The vacuolar arginine pool was exchangeable with lysine added to the medium and was decreased by treatment of the cells with the mating pheromone, alpha-factor.

Amino Acids↗
PubMed1988

Mutants of Saccharomyces cerevisiae with defective vacuolar function.

Mutants of the yeast Saccharomyces cerevisiae that have a small vacuolar lysine pool were isolated and characterized. Mutant KL97 (lys1 slp1-1) and strain KL197-1A (slp1-1), a prototrophic derivative of KL97, did not grow well in synthetic medium supplemented with 10 mM lysine. Genetic studies indicated that the slp1-1 mutation (for small lysine pool) is recessive and is due to a single chromosomal mutation. Mutant KL97 shows the following pleiotropic defects in vacuolar functions. (i) It has small vacuolar pools for lysine, arginine, and histidine. (ii) Its growth is sensitive to lysine, histidine, Ca2+, heavy metal ions, and antibiotics. (iii) It has many small vesicles but no large central vacuole. (iv) It has a normal amount of the vacuolar membrane marker alpha-mannosidase but shows reduced activities of the vacuole sap markers proteinase A, proteinase B, and carboxypeptidase Y.

Arginine↗