Biomedical subjects

K Kodaira

Publications and source records attributed to K Kodaira.

At least 19 recordsLinked to original sources

PubMed1999

Cloning and characterization of the gene encoding mouse osteoclast differentiation factor.

Osteoclast differentiation factor (ODF), a ligand for osteoclastogenesis inhibitory factor (OCIF)/ osteoprotegerin (OPG), is a member of the membrane-associated tumor necrosis factor (TNF) family and induces osteoclast-like cell formation in vitro. In the present study, mouse ODF genomic clones were isolated and sequenced to determine their gene structure. The mouse ODF gene is a single copy gene consisting of five exons and spans approximately 40kb of the mouse genome. The first exon encodes the intracellular and transmembrane domains. The extracellular region of ODF containing the TNF homologous domain is encoded by exons 1 through 5. The translation-termination codon and six polyadenylation signal residues are present in exon 5. A major transcription-initiation site is present 143 nucleotides upstream of the initiation-ATG codon. This genomic organization is similar to that of other members of the TNF family, especially the CD40 ligand.

Animals↗

PubMed1999

High-level expressing YAC vector for transgenic animal bioreactors.

The position effect is one major problem in the production of transgenic animals as mammary gland bioreactors. In the present study, we introduced the human growth hormone (hGH) gene into 210-kb human alpha-lactalbumin position-independent YAC vectors using homologous recombination and produced transgenic rats via microinjection of YAC DNA into rat embryos. The efficiency of producing transgenic rats with the YAC vector DNA was the same as that using plasmid constructs. All analyzed transgenic rats had one copy of the transgene and produced milk containing a high level of hGH (0.25-8.9 mg/ml). In transgenic rats with the YAC vector in which the human alpha-lactalbumin gene was replaced with the hGH gene, tissue specificity of hGH mRNA was the same as that of the endogenous rat alpha-lactalbumin gene. Thus, the 210-kb human alpha-lactalbumin YAC is a useful vector for high-level expression of foreign genes in the milk of transgenic animals.

Animals↗

PubMed1999

Terrestrial gamma ray dose rates of Brunei Darussalam.

GPS-indexed in-situ and car-borne survey of terrestrial gamma-ray dose rates were carried out in Brunei and adjacent areas using two portable NaI(Tl) counters. The mean and population weighted average dose rates for Brunei are 34 and 33 nGy/h, respectively. The car-borne data and the in-situ data when spectral analysed separately, were found to show fractal behaviour with D of 1.7 and 1.8, respectively. A contour map of the dose rates was also produced.

Air Pollutants, Radioactive↗

PubMed1997

Functional and structural features of the holin HOL protein of the Lactobacillus plantarum phage phi gle: analysis in Escherichia coli system.

Lactobacillus plantarum phage phi gle has two consecutive cell lysis genes hol-lys (Oki et al., 1996b). In the present study, functional and structural properties of the hol protein (Hol) were characterized in Escherichia coli. Electron microscopic examinations showed that hol under plac in E. coli XL1-Blue injured the inner membrane to yield empty ghost cells with the bulk of the cell wall undisturbed. Northern blot analysis indicated that hol-lys genes under plac were co-transcribed, although the amount of hol transcript was larger than that of lys, ceasing via an apparently rho-independent terminator just downstream of hol. However, deletion and/or fusion experiments suggested that: (1) the N-terminal half of phi gle Hol composed of three putative transmembrane domains may be responsible for interaction with membrane; (2) the N-terminal end (five amino acids) seems nonessential; and (3) the C-terminal half containing charged amino acids appears to be involved in proper hol function. These results suggest that phi gle Hol is a member of the lambdoid holin family, but divergent in several properties from lambda holin.

Amino Acid Sequence↗

PubMed1996

Cloning and nucleotide sequence of the major capsid proteins of Lactobacillus bacteriophage phi gle.

Bacteriophage phi gle was induced from a lysogenic Lactobacillus strain Gle. phi gle genome is double-stranded DNA of approximately 42.5 kilo-base (kb) pairs. SDS poly-acrylamide gel electrophoresis demonstrated that the phage particles contain 4 major structural (capsid) proteins, gpB, gpG, gpO, and gpP, whose molecular weights (MW) are estimated to be 64, 43, 29 and 26 kilodaltons (kDa), respectively. More than 16 minor proteins ranging from 113 to 9.6 kDa were also detected. The genes for the major capsid proteins were cloned and each DNA sequence was determined. N-terminal amino acid alignments determined by protein sequencing completely coincided with those deduced from the nucleotide sequences.

Amino Acid Sequence↗

PubMed1996

Transgene expression in mammary glands of newborn rats.

Transgene expression in the mammary glands of newborn rats was studied to establish an early selection system for transgenic animals producing exogenous proteins in their milk during lactation. A fusion gene composed of the bovine alpha S1 casein gene promoter and the human growth hormone gene was microinjected into rat embryos. Transgenic lines that produced human growth hormone in their milk were established and used in this study. Immediately after birth, and without any hormone treatment, human growth hormone was found in the extracts of mammary glands from both male and female rats derived from the line secreting human growth hormone in their milk. The expression of the transgene in mammary glands of newborn rats was also detected by the presence of human growth hormone mRNA. Nontransgenic newborn rats did not express the human growth hormone gene in their mammary glands, while the mRNA for rat alpha casein, an endogenous milk protein, was found in all mammary glands from both transgenic and nontransgenic neonates. These results show that analyzing the expression of transgenes in the mammary glands of neonates is a valuable tool to select the desired transgenic animals and to shorten the selection schedules establishing the transgenic animals.

Animals↗

PubMed1996

Overexpression of c-myc induces apoptosis at the prophase of meiosis of rat primary spermatocytes.

Transgenic rats expressing the rat c-myc gene under the control of the human metallothionein II A promoter were produced. We found that the female transgenic rats were fertile, but that the male transgenic rats were sterile. Atrophy of the seminiferous tubules and depletion of sperm were observed in the sterile male testes. The expression of differential stage-specific mRNAs, including those of the c-kit receptor proto-oncogene, meiotic heat-shock protein 70 gene, acrosin gene, and transition protein 1 gene, was analyzed by the reverse transcriptase-polymerase chain reaction during spermatogenesis. The results suggested that spermatogenesis in these sterile rats were arrested at the prophase of meiosis in the primary spermatocytes. We found that apoptotic DNA fragmentation occurred in primary spermatocytes of the sterile transgenic rats. These results suggest that overexpression of the c-myc gene induces apoptosis at the prophase meiosis of the primary spermatocytes thereby causing male sterility in the c-myc transgenic rats.

Animals↗

PubMed1996

The virion proteins encoded by bacteriophage phi K and its host-range mutant phi KhT: host-range determination and DNA binding properties.

The microvirid phage phi K, specific for Escherichia coli K12, contains a circular single-stranded (SS) DNA in the icosahedral virion, which comprises four phage gene products, F (capsid), G (major spike), H (minor spike), and J (core). phi KhT, a host-range mutant of phi K, can grow on E. coli C and B, besides K12, and is more thermosensitive than the parental phage phi K. Sequencing analysis revealed that the genome of phi K and phi KhT consists of 6,089 nucleotides (nt), and codes for eleven genes, whose sequences are similar to those of alpha 3, phi X174, and G4 infective to strain C. In phi KhT, two nt had changed: one is in the gene G, resulting in replacement of the 75th codon Ala with Ser, and the other is at 67th codon of the gene H: Val to Ala. Chemically synthesized gene J protein composed of 23 amino acids (aa) binds to phi K SS DNA more tightly than and preferentially over the host E. coli SS-DNA-binding protein (SSB). These results indicate that the two spike proteins G and H are involved in the determination of phi K host-range, and support a model in which the gene J protein functions in packaging the viral SS DNA into the virion vesicle.

Amino Acid Sequence↗

PubMed1996

Common carotid artery wall properties in Takayasu's arteritis.

The vessel wall properties of the common carotid artery have been noninvasively and quantitatively assessed with an ultrasonic instrument. Stiffness parameter beta, which represents the mechanical properties of the vessel, was calculated from the relationship between blood pressure and the diameter of the artery. There are no reports that quantitatively assess wall properties in Takayasu's arteritis. The authors compared, in vivo, the vessel wall properties of the common carotid artery in 14 patients with Takayasu's arteritis versus those in 60 normal subjects (controls). They measured changes in the inner diameter of the artery between systole and diastole with an ultrasonic, phase-locked, echo-tracking system. Beta was significantly higher in Takayasu's arteritis than in normal subjects (better than a 99% confidence interval). The findings for each decade were as follows: 3rd decade (20s): 35.7 +/- 28.9 vs 5.01-6.46, P=0.0001; 4th decade (30s): 19.5 +/- 9.71 vs 6.09-7.80, P=0.02; 5th decade (40s): 26.2 +/- 11.3 vs 7.26-9.28, P = 0.0001; 6th decade (50s): 19.1 +/- 4.27 vs 8.66-11.25, P = 0.0001. Takayasu's arteritis significantly impaired the mechanical performance of the common carotid artery. Thus, beta shows promise as a useful diagnostic indicator of Takayasu's arteritis.

Adult↗

PubMed1995

Determination of the single strand origin of Shigella sonnei plasmid pKYM.

The Shigella sonnei plasmid pKYM replicates by a rolling-circle mechanism in Escherichia coli. A 571 nucleotides HincII restriction fragment of the pKYM DNA harbors two potential hairpin loops (I and II). We cloned the fragment into a -ori defective M13 vector phage, M13 delta lac183. The chimera phage, MDKY5, showed a larger plaque size, and increased phage yield and rate of progeny replicative form DNA (RF) synthesis. Rifampicin reduced rate of conversion of the single- to double-stranded RF DNA. In addition, we introduced nucleotide deletions within the cloned pKYM DNA, by Bal31 nuclease digestion. Each of the deletion mutants thus constructed was lacking in a sequence containing the hairpin loops and formed smaller plaques. The in vivo analyses revealed that a 136 nucleotides sequence containing the two hairpins I and II is the pKYM minus origin for complementary strand synthesis (single strand origin, referred to as SSO) and harbors a recognition site(s) by host E. coli RNA polymerase, for primer RNA synthesis. Moreover, we found a 24 nt sequence, upstream of the SSO domain having 83% homology to the recombination site A (RSA) which functions in plasmid sitespecific recombination and/or transfer.

Base Sequence↗

PubMed1995

Comparative studies on the minus origin mutants of Escherichia coli spherical single-stranded DNA phages.

The minus origins for complementary strand DNA synthesis (-ori) of Escherichia coli spherical single-stranded DNA (microvirid) phages G4, phi K, alpha 3, and St-1 closely resemble each other in DNA structure and contain two potential secondary hairpin loops (I and II) that have been implicated as direct recognition sites for host E. coli dnaG protein (primase). We introduced mutations (deletion or insertion) within the -ori regions of phi K and G4 by the nuclease digestion method. Mutants thus constructed produced minute plaques, showed thermosensitivity, and they remarkably reduced the phage yield and rate of viral DNA synthesis. Deletions in the phi K mutants (dTa) were ranging from 1 nucleotide (nt) to 102 nt centered at the hairpin II; a dTa8 mutant was entirely lacking in the two hairpins besides the starting point for primer RNA synthesis. On the other hand, the G4 mutants (dSa) had deletions centered at hairpin I; two mutants dSa35 and dXN completely lost the hairpin I and the primer RNA starting point. In addition, progeny phage populations of several phi K and G4 mutants contained revertant-like phages. DNA sequencing analysis revealed that these secondary phages had been generated by spontaneous DNA rearrangement with additional insertion or deletion near the parental mutation sites, via an unknown recA-independent pathway.

Base Sequence↗

PubMed1994

An acrosomal protein, sp32, in mammalian sperm is a binding protein specific for two proacrosins and an acrosin intermediate.

An acrosomal protein, sp32, was completely purified from acid extracts of ejaculated porcine sperm. Purified sp32 gave a single 32-kDa protein band on SDS-polyacrylamide gel electrophoresis and was characterized as a binding protein specific for 55-, 53-, and 49-kDa forms of (pro)acrosin. This protein was not capable of binding a 43-kDa acrosin intermediate and 35-kDa mature acrosin. sp32 significantly accelerated autoactivation of proacrosin at a basic pH in vitro and affected the maturation pathway of proacrosin. In the presence of sp32, the 49-kDa acrosin intermediate from the 55- and 53-kDa proacrosins was accumulated, instead of the 43-kDa acrosin intermediate. These results suggest that sp32 interacts with both the amino- and carboxyl-terminal sequences of the 53-kDa proacrosin. The cDNA clones coding for porcine and guinea pig sp32 have been identified from testis cDNA libraries in lambda gt11. The deduced amino acid sequence indicates that sp32 is initially synthesized as a 61-kDa precursor protein with a putative signal peptide at the amino terminus. The carboxyl-terminal half of the precursor molecule corresponds to the mature sp32. Thus, sp32 is produced by post-translational modification of the precursor. The binding of sp32 to proacrosin may be involved in packaging the acrosin zymogen into the acrosomal matrix.

Acrosin↗

PubMed1994

Correlation of ultrasound-measured common carotid artery stiffness with pathological findings.

To quantitatively and noninvasively evaluate common carotid atherosclerosis in a series of patients, we measured the stiffness parameter beta, which represents the mechanical properties of the vessel. beta was calculated from the relationship between blood pressure and the diameter of the artery as measured by an ultrasonic, phase-locked, echotracking system. Increases in the severity grade of atherosclerosis as subsequently determined at autopsy were correlated with increased beta values in 60 common carotid arteries (r = .68). Patients with beta values greater than 13 had a pathological diagnosis of atherosclerosis in the common carotid artery. The sensitivity of this discrimination ratio was 80%, and the specificity was 80% as well. Thus, beta shows promise as a useful diagnostic indicator for detecting asymptomatic common carotid atherosclerosis.

Adult↗

PubMed1993

The C. elegans unc-18 gene encodes a protein expressed in motor neurons.

The C. elegans unc-18 gene is required to maintain normal acetylcholine levels. We determined the complete structure of an unc-18 cDNA that encodes a protein of 591 highly charged and hydrophilic amino acids. The protein shows sequence similarity with elements of the secretory pathway in the yeast S. cerevisiae. Antibodies raised against a portion of the unc-18-encoded protein (UNC-18) detected a 68 kd soluble antigen on immunoblots and intensely stained all vertical cord motor neurons in situ. These findings suggest that UNC-18 participates in the axonal transport system and influences the acetylcholine flow in motor neurons.

Amino Acid Sequence↗

PubMed1993

A study on cerebral nicotine receptor distribution, blood flow, oxygen consumption, and other metabolic activities--a study on the effects of smoking on carotid and cerebral artery blood flow.

We investigated middle cerebral artery flow velocity (MCA-FV) by a noninvasive method to determine whether or not smoking causes an increase in cerebral blood flow (CBF). Furthermore we determined sequentially the changes in CBF caused by smoking in order to evaluate changes in responses at different times in daily activities and the effect from meals. The subjects were 25 healthy individuals ranging in age from 20 to 36 yr. MCA-FV was measured by a transcranial Doppler system. They smoked a filtered cigarette for 5 min at 1 P.M., 3 P.M., 6 P.M., 8 P.M., 10 P.M., 8 A.M., and 11 A.M. Results (1) Smoking caused increases in both common carotid artery flow volume and MCA-FV, and the percentage increase of these parameters showed a good correlation (r = 0.809). (2) MCA-FV increased significantly during the first (by 6.6%) and second halves (by 5.4%) of the smoking period. (3) The change in MCA-FV after meals was slight. (4) Smoking tended to increase MCA-FV during each smoking session but the changes were not significant. The pulsatility index reduced significantly during almost every smoking session. These results lead to the conclusion that smoking reduces vascular resistance in cerebral arteries and increases CBF.

Adult↗

PubMed1992

Nucleotide sequence of the genome of the bacteriophage alpha 3: interrelationship of the genome structure and the gene products with those of the phages, phi X174, G4 and phi K.

The complete nucleotide sequence of the genome of the circular single-stranded DNA (isometric) phage alpha 3 has been determined and compared with that of the related phages phi X174 and G4. The alpha 3 genome consists of 6087 nucleotides, which is 701 nucleotides longer than the nucleotide sequence of the phi X174 genome and 510 nucleotides more than that of the G4 genome. The results demonstrated that the three phage species have 11 homologous genes (A, A*, B, C, K, D, E, J, F, G and H), the order of which is fundamentally identical, suggesting that they have evolved from a common ancestor. The sequence of some genes and untranslated intergenic regions, however, differs significantly from phage to phage: for example, the degree of amino acid sequence homology of the gene product is averaged at 47.7% between alpha 3 and phi X174 and 46.9% between alpha 3 and G4, and alpha 3 has a remarkable longer intergenic region composed of 758 nucleotides between the genes H and A compared with the counterparts of phi X174 and G4. Meanwhile, in vivo experiments of genetic complementation showed that alpha 3 can use none of the gene products of phi X174 and G4, whereas the related phage phi K can rescue alpha 3 nonsense mutants of the genes B, C, D and J. These sequencing and in vivo rescue results indicated that alpha 3 is closely related to phi K, but distantly remote from phi X174 or G4, and supported an evolutional hypothesis which has been so far proposed that the isometric phages are classified into three main groups: the generic representatives are phi X174, G4 and alpha 3.

Amino Acid Sequence↗

PubMed1991

Correlation of common carotid flow volume measured by ultrasonic quantitative flowmeter with pathological findings.

To evaluate the possibility of quantitatively diagnosing carotid and cerebral atherosclerosis noninvasively, we measured common carotid flow volume in 60 sides (30 patients), using an ultrasonic quantitative flowmeter, and then compared these findings to the severity score of carotid and cerebral atherosclerosis as determined at autopsy. Stenosis decreased common carotid flow volume in the carotid and cerebral arteries. Increases in the severity score varied inversely with reduced flow volume, which was high in inverse correlation (r = -0.696). Patients with flow volumes of 8.5 ml/sec or greater did not have stenosis greater than or equal to 75%, whereas all patients with flow volumes of 6.4 ml/sec or less had stenosis greater than or equal to 50%, with 45% of these having stenosis greater than or equal to 75%. These pathological findings confirm that the common carotid flow volume reflects the degree of carotid and cerebral atherosclerosis present and that the lower limit of common carotid flow volume in healthy subjects is 6.5 ml/sec.

Arteriosclerosis↗

PubMed1990

Acrosin biosynthesis in meiotic and postmeiotic spermatogenic cells.

It has been widely accepted that mammalian sperm acrosin is first synthesized only in the postmeiotic stages of spermatogenic cells. In this study, we carried out Northern blot analysis of RNAs prepared from purified populations of mouse spermatogenic cells. The acrosin mRNA was obviously found in meiotic pachytene spermatocytes, and the mRNA content markedly increased in postmeiotic round spermatids. Also, the acrosin mRNA in pachytene spermatocytes was functionally associated with polysomes. These results provide evidence that acrosin biosynthesis is already started in meiotic cells and continues through the early stages of spermiogenesis.

Acrosin↗