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N Fukunaga

Publications and source records attributed to N Fukunaga.

At least 37 records · Page 2Linked to original sources
PubMed1995

Identification of virulence-associated antigens and plasmids in Rhodococcus equi from patients with AIDS.

Rhodococcus equi is an emerging opportunistic pathogen of human immunodeficiency virus-infected patients. However, little is known about the characteristics of R. equi isolates from humans. This study characterized the plasmid content, expression of a virulence-associated antigen, and mouse virulence of 19 R. equi isolates from patients with and without AIDS. EcoRI digestion patterns and Southern, Western, and virulence analyses of these isolates with cryptic plasmids allowed definition of a new category of R. equi. Isolates from patients with AIDS tended either to be virulent and have 15- to 17-kDa antigens and an 85-kb plasmid (10(6) bacteria needed for lethality) or have intermediate virulence (10(7) bacteria needed for lethality) and one of four distinct large plasmids that share DNA homology and express a 20-kDa antigen. Most of the non-AIDS isolates were avirulent (> 10(8) bacteria needed for lethality) and did not express any of these antigens.

AIDS-Related Opportunistic Infections↗
PubMed1995

Differential expression in Escherichia coli of the Vibrio sp. strain ABE-1 icdI and icdII genes encoding structurally different isocitrate dehydrogenase isozymes.

The expression of two structurally different isocitrate dehydrogenase isozymes of Vibrio sp. strain ABE-1 in Escherichia coli was examined. At a low temperature (15 degrees C), a thermolabile and monomeric type isozyme (IDH-II), which is quite different in amino acid sequence from the E. coli isocitrate dehydrogenase, was expressed and conferred glutamate prototrophic ability on an E. coli mutant defective in isocitrate dehydrogenase. The ability of IDH-II to confer restoration of the E. coli mutant to glutamate prototrophy was similar to that of IDH-I, which is a dimeric enzyme homologous to the E. coli isocitrate dehydrogenase. At a high temperature (37 degrees C), no functional IDH-II was expressed. Transcription of icdI and icdII genes, which encode IDH-I and IDH-II, respectively, was regulated differently by different environmental conditions. The level of icdII mRNA was increased by lowering the growth temperature for E. coli transformants, while the level of icdI mRNA was increased when E. coli transformants were cultured in acetate minimal medium. Similar patterns of transcriptional regulation of the two icd gene were observed also in Vibrio sp. strain ABE-1. However, activity of isocitrate dehydrogenase kinase, which can phosphorylate IDH-I and consequently inactivate the enzymatic activity, was detected in cell lysates of E. coli but not of Vibrio sp. strain ABE-1.

Acetates↗
PubMed1994

Down-regulation of topoisomerase I in mammalian cells following ionizing radiation.

Modulators of the DNA unwinding enzyme, topoisomerase I (Topo I), inhibit DNA repair and augment the lethal effects of X-rays and other agents that create breaks in DNA. To investigate the role of Topo I in DNA repair, we examined Topo I activity before and after X-irradiation using confluence-arrested hamster and human cells. Topo I activities were higher in unirradiated neoplastic compared to normal hamster or human cells. Following ionizing radiation, however, enzyme activities were dramatically down-regulated to a greater extent in tumor than in normal cells. The extent of Topo I down-regulation correlated to some extent with survival enhancement in irradiated cells. Enzyme activities were down-regulated within 5 min in hamster and human cells. Recovery of Topo I activities in X-irradiated hamster cells required 12 h, whereas irradiated human cells recovered in only 70 min. Decreased Topo I activity was also noted after UV irradiation. In contrast, Topo I protein and mRNA levels remained unchanged following radiation. Administration of 5 mM 3-aminobenzamide or 0.5 mM PD 128763, inhibitors of poly(ADP-ribose) transferase, prevented Topo I down-regulation in X-irradiated or UV-irradiated human or hamster cells. Thus, decreases in Topo I activity following DNA damage are likely caused by ADP-ribosylation of the enzyme. Down-regulation of Topo I may prevent its binding to single-stranded DNA nicks created by X-irradiation, allowing the DNA repair complex (which is concomitantly activated by ADP-ribosylation) access to these lesions.

Adenosine Diphosphate Ribose↗
PubMed1993

Isolation of x-ray-inducible transcripts from radioresistant human melanoma cells.

Twelve x-ray-induced transcripts (xips), differentially expressed 8- to 230-fold in x-irradiated versus unirradiated radioresistant human melanoma (U1-Mel) cells, were isolated as cDNA clones (xip1 through xip12) after four rounds of differential hybridization. Northern analyses revealed rare, medium, and abundant xips, ranging in size from 1.2 to 10 kb. All transcripts were transiently expressed and induced by low, but not by high (> 600 cGy), doses of radiation. Three transcripts (xip4, -7, and -12) were induced only by ionizing radiation, and many (i.e., xip1, -2, -3, -5, -6, -8, -9, -10, and -11) were also induced by UV irradiation or phorbol 12-myristate 13-acetate. Heat shock did not induce any of the xips, but it decreased basal levels of xip4, -7, -11, and -12. Three xip cDNA clones were identified as encoding thymidine kinase, DT diaphorase, and tissue-type plasminogen activator. The remaining nine cDNA clones showed little homology to known genes. Three clones contained regions homologous to c-fes/fps protooncogene, recombination activating gene 1, or the human angiogenesis factor gene. X-ray-inducible genes may function in damaged cells to regulate DNA repair, apoptosis, mutagenesis, and carcinogenesis.

Base Sequence↗
PubMed1993

Genes encoding two isocitrate dehydrogenase isozymes of a psychrophilic bacterium, Vibrio sp. strain ABE-1.

The genes coding for two structurally different isocitrate dehydrogenase isozymes (IDH-I and IDH-II) of a psychrophilic bacterium, Vibrio sp. strain ABE-1, were cloned and sequenced. Open reading frames of the genes (icdI and icdII) are 1,248 and 2,229 bp in length, respectively. The amino acid sequences predicted from the open reading frames of icdI and icdII corresponded to the N-terminal amino acid sequences of the purified IDH-I and IDH-II, respectively. No homology was found between the deduced amino acid sequences of the isozymes; however, the IDH-I, a dimeric enzyme, had a high amino acid sequence identity (74.3%) to the Escherichia coli IDH. The deduced amino acid sequence of the IDH-II, a monomeric enzyme, was not related to any known sequence. However, the IDH-II had an amino acid sequence homologous to that of a cyanogen bromide-cleaved peptide containing a putative active-site methionyl residue of the monomeric IDH of Azotobacter vinelandii. The two genes (icdlI and icdII) were found to be tandemly located in the same orientation. Northern (RNA) blot analyses showed that the two genes are transcribed independently. Primer extension experiments located single transcriptional start sites 39 and 96 bp upstream of the start codons of icdI and icdII, respectively. The amount of icdI transcript but not icdII increased when Vibrio sp. strain ABE-1 cells were cultured in acetate minimal medium.

Amino Acid Sequence↗
PubMed1992

Enhanced induction of tissue-type plasminogen activator in normal human cells compared to cancer-prone cells following ionizing radiation.

Normal human fibroblast (i.e., GM2936B, GM2907A, and IMR-90) and cancer-prone human fibroblast (i.e., Fanconi's anemia, Bloom's syndrome, and Ataxia telangiectasia) cells demonstrated the induction of intracellular and extracellular levels of tissue-type plasminogen activator (t-PA) at 6 and 12 hr, respectively, following ionizing radiation. Induced t-PA enzymatic activities following ionizing radiation were blocked by actinomycin D treatments. t-PA enzymatic activities were induced over 14-fold in Ataxia telangiectasia cells, over 9-fold in Bloom's syndrome cells, and over 6-fold in Fanconi's anemia cells, as compared to normal human fibroblasts. Similarly, the induction of t-PA mRNA levels in cancer-prone cells were between 5- to 10-fold higher than those observed in normal cells following equitoxic doses of ionizing radiation. Temporal induction of t-PA mRNA levels for normal and cancer-prone human cells were consistent with quantifiable enzymatic activities. The elevated induction of an intracellular protease (i.e., t-PA) in cancer-prone human cells is reminiscent of an "SOS"-like response observed in yeast and bacteria.

Ataxia Telangiectasia↗
PubMed1992

Purification and characterization of monomeric isocitrate dehydrogenase with NADP(+)-specificity from Vibrio parahaemolyticus Y-4.

NADP(+)-dependent isocitrate dehydrogenase [IDH: EC 1.1.1.42] was purified to electrophoretic homogeneity from Vibrio parahaemolyticus Y-4, and shown to be a monomeric protein of molecular weight 80,000 with a pI of 5.0. The amino acid composition and partial sequence at the N-terminus resembled those reported for other bacterial monomeric IDHs. Immunotitration with antisera to the monomeric and dimeric enzymes (antisera to IDH-II and -I of Vibrio ABE-1) showed an immunochemical distinction between the monomeric and dimeric IDHs, but there is similarity within the IDHs of each group. The circular dichroism spectra of the native and heat-denatured enzyme are also similar to those of monomeric IDH (IDH-II of Vibrio ABE-1). These monomeric IDHs are proteins comprising 17-22% helix and 25-35% beta-pleated sheet in the native state.

Amino Acid Sequence↗
PubMed1992

Effect of Ca2+ and K+ on the intracellular pH of an Escherichia coli L-form.

The L-form NC7, derived from Escherichia coli K12, grew in a complex medium containing 0.2 M-CaCl2 as osmotic stabilizer, but not at pH values above 7.8. The cessation of growth at alkaline pH was not due to cell death. In complex media containing K+ or Na+, the L-form grew ove a wide pH range. Growth at alkaline pH was inhibited by 1 mM-amiloride, indicating that Na+/H+ antiport activity was required for growth at alkaline pH. The internal pH (pHi) of the L-form in media containing K+, Na+ or Ca2+ was constant at about 7.8 to 8.0 at external pH (pHo) values of 7.2 and 8.2. The rates of O2 consumption by intact cells, lactate oxidation by membrane vesicles from cells grown in Ca(2+)-containing medium, and cell division were all strongly repressed under alkaline conditions.

Amiloride↗
PubMed1989

Mechanism of biosynthesis of unsaturated fatty acids in Pseudomonas sp. strain E-3, a psychrotrophic bacterium.

Biosynthesis of palmitic, palmitoleic, and cis-vaccenic acids in Pseudomonas sp. strain E-3 was investigated with in vitro and in vivo systems. [1-14C]palmitic acid was aerobically converted to palmitoleate and cis-vaccenate, and the radioactivities on their carboxyl carbons were 100 and 43%, respectively, of the total radioactivity in the fatty acids. Palmitoyl coenzyme A desaturase activity was found in the membrane fraction. [1-14C]stearic acid was converted to octadecenoate and C16 fatty acids. The octadecenoate contained oleate and cis-vaccenate, but only oleate was produced in the presence of cerulenin. [1-14C]lauric acid was aerobically converted to palmitate, palmitoleate, and cis-vaccenate. Under anaerobic conditions, palmitate (62%), palmitoleate (4%), and cis-vaccenate (34%) were produced from [1-14C]acetic acid, while they amounted to 48, 39, and 14%, respectively, under aerobic conditions. In these incorporation experiments, 3 to 19% of the added radioactivity was detected in released 14CO2, indicating that part of the added fatty acids were oxidatively decomposed. Partially purified fatty acid synthetase produced saturated and unsaturated fatty acids with chain lengths of C10 to C18. These results indicated that both aerobic and anaerobic mechanisms for the synthesis of unsaturated fatty acid are operating in this bacterium.

Acetates↗
PubMed1989

Osteoma of the testis with its histogenetic consideration.

Although a few cases of osteoma in renal pelvis and urinary bladder have been reported, no cases of osteoma in the testis have been presented. A case of so-called osteoma of the testis incidentally found in a 30-year-old man was presented with discussion for its histogenetic considerations.

Adult↗
PubMed1987

Isozymes of isocitrate dehydrogenase from an obligately psychrophilic bacterium, Vibrio sp. strain ABE-1: purification, and modulation of activities by growth conditions.

Each of the two isozymes, which are different in thermostability and quaternary structure, of isocitrate dehydrogenase (NADP+) [IDH: EC 1.1.1.42] was purified to an electrophoretically homogeneous state from an obligately psychrophilic marine bacterium, Vibrio sp. strain ABE-1. Hydrophobic chromatography was an efficient procedure to separate the two isozymes from each other. The isoelectric points of isozyme I (IDH-I; a dimer, Mr 88,100) and isozyme II (IDH-II; a monomer, Mr 80,500) were found to be pH 4.9 and 5.2, respectively. The two isozymes were similar in amino acid compositions, though there were slight differences in the contents of nonpolar and hydroxyl amino acids. However, their NH2-terminal amino acid sequences and immunochemical properties were clearly different from each other. The NH2-terminal amino acid sequence analysis also indicated that the subunits of IDH-I are chemically identical or highly homologous. Non-immuno-crossreactivity between the isozymes enabled us to measure the intracellular contents of the isozymes. IDH-I and -II were found to be differentially regulated in vivo by various growth conditions. IDH-I was induced by acetate, while IDH-II remained almost unchanged.

Acetates↗
PubMed1985

[An autopsy case of Prader-Labhart-Willi syndrome].

An autopsy case of 23-years-old man with Prader-Labhart-Willi syndrome (P-L-W syndrome), who had died by acute renal failure due to burn injury, was reported. P-L-W syndrome was constituted by hypotonia, hypogonadism, hypomentia, obesity and other minor anomalies, however, CNS anomaly had not been reported. The patient sat at 3 years of age, walked at 4 years old, began to utter single words at 3-4 years, and he began to obese at 4 years of age. He fulfilled the condition of P-L-W syndrome mentioned above. On his age 15, laboratory findings on admission revealed remarkable diabetic pattern by oral glucose tolerance test and intelligence quotient was 28, and the other laboratory findings were within normal limit. During his clinical history, complications of diabetes mellitus, such as diabetic retinopathy and neuropathy, were aggrevated, and upstanding and gait were impossible at 20 years of age. On his age 23, he suffered from burn injury at left lower extremity and he fell in acute renal insufficiency. Five autopsy cases of P-L-W syndrome have been reported so far, however, CNS anomaly has not been observed. Following anomalies in our case was recognized, such as shortness of the frontal lobe, partial micropolygyria of the dentate nucleus, heterotopia of the inferior olivary nucleus, ectopia of Purkinje cell in the molecular layer, heterotopia of middle sized neuron in the deep white matter of the cerebellum and large number of residual nerve cells in the cerebral subcortical white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Blue nevus of the uterine cervix. An ultrastructural study of two cases.

Two cases of blue nevus of the uterine cervix were studied ultrastructurally. Both were incidental findings in hysterectomy specimens. The pigmented cells were characterized by both solitary and compound melanosomes at different stages of development and by basement membrane surrounding the interdigitated cytoplasm. The evidence suggests that the pigmented cells in uterine blue nevus may be Schwann's cells with melanin synthesis.

Female↗
PubMed1979

Purification and some properties of two NADP+-specific isocitrate dehydrogenases from an obligately psychrophilic marine bacterium, Vibrio sp., strain ABE-1.

Two isozymes of NADP+-specific isocitrate dehydrogenase [ICDH; EC 1.1.1.42] were confirmed to be present in an obligately psychrophilic marine bacterium, Vibrio sp., strain ABE-1, on the basis of the temperature-activity curve and electrophoretic mobilities. These isozymes were separated and purified about 170-fold for isozyme I (specific activity at 40 degrees C, 24.3 units/mg protein) and about 180-fold for isozyme II (specific activity at 20 degrees C, 59.2 units/mg protein), though the isozymes were still not homogeneous. The molecular weights of these isozymes determined by gel filtration were both about 85,000, but the properties of the isozymes were considerably different from each other. The thermostability of isozyme I resembled those of mesophiles, but isozyme II was extremely labile above 20 degrees C. NaCl affected the ICDH isozymes in different ways; the salt protected isozyme I from heat inactivation, but not isozyme II. Nevertheless it enormously enhanced the activity of isozyme II at low concentrations. Moreover, these ICDH isozymes showed different pH optima, Km values for isocitrate, susceptibilities to concerted inhibition by glyoxylate plus oxalacetate, and effects of 2-mercaptoethanol on their stabilities.

Drug Stability↗
PubMed1979

Congenital cerebellar hypoplasia in newborn calves.

A sporadic outbreak of congential cerebellar ataxia (CCA) was seen in calves. The abnormality of this disorder of the central nervous system characteristic was cerebellar hypoplasia, which was observed in eight calves. The cerebellum was almost completely absent in some of these calves and approximately one-fifth of the normal size in some others. Six of the eight calves were also affected with hydrocephaly. The significant changes of the cerebellum were complete or partial destruction of the cortex, deficiency of granules and/or Purkinje cells, clumping of the remaining granule cells, and an irregular cavity formation in the terminal portion of the folium. The clinicopathological changes of CCA quite closely resembled those of the bovine viral diarrhea-mucosal disease virus infection.

Animals↗