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Biomedical subjects

A Nakazawa

Publications and source records attributed to A Nakazawa.

At least 19 recordsLinked to original sources

Analysis of an upstream regulatory sequence required for activation of the regulatory gene xylS in xylene metabolism directed by the TOL plasmid of Pseudomonas putida.

Transcription from the promoter of a positive regulatory gene, xylS, on the TOL plasmid of Pseudomonas putida is activated by another positive regulator, XylR, in the presence of m-xylene and is dependent on RNA polymerase containing the NtrA protein (sigma 54). Deletion analysis of the upstream region of the xylS gene revealed an upstream regulatory sequence (URS), located between 145 and 188 bp upstream from the transcription start site. The URS is active in either orientation and can be placed 3.9 kb further upstream without loss of activity. Dependence of activation on helical periodicity was observed in the region between the URS and the promoter of the xylS gene, suggesting DNA loop formation between these two sites, which are located about 100 bp apart. The expression of xylR was autogenously repressed by XylR protein. This autogenous repression is decreased in an NtrA- background, irrespective of the presence of the xylS promoter in cis, indicating that NtrA protein, or NtrA-containing RNA polymerase that is not bound to the xylS promoter, is involved in the binding of XylR protein to the URS.

Bacterial Proteins

Detection of human papillomavirus types 16 and 18 in the exfoliated cervical cells using the polymerase chain reaction.

We applied the polymerase chain reaction (PCR) to detect HPV 16 and 18 in cytological samples obtained from the uterine cervices of Japanese women. HPV infection was detected in 17 (25%) of 67 with CIN and 11 (37%) of 30 with cervical carcinoma. It is notable that 11 (16%) of 69 women with normal cervices were infected with either HPV 16 or 18. The polymerase chain reaction is sensitive and useful for epidemiological studies.

Adolescent

Sialyl-Tn, sialyl-Lewis Xi, CA 19-9, CA 125, carcinoembryonic antigen, and tissue polypeptide antigen in differentiating ovarian cancer from benign tumors.

Serum sialyl-Tn, sialyl-Lewis Xi, CA 19-9, CA 125, carcinoembryonic antigen (CEA), and tissue polypeptide antigen were measured in 65 women with early-stage ovarian cancer (45 stage I and 20 stage II cases) and 317 with benign pelvic masses. As a single assay, sialyl-Tn showed the best sensitivity and specificity, 46 and 92%, respectively. CA 19-9 detected the greatest number of cancer patients but had the lowest specificity. The combination of sialyl-Tn, CA 125, tissue polypeptide antigen, and CEA seemed to perform the best, with a sensitivity and specificity of 71 and 76%, respectively. The combination of sialyl-Tn, CA 125, and tissue polypeptide antigen gave similar results and may be more cost-effective. However, one-fifth of the patients with early-stage cancer still showed up as false negatives even with use of the six markers in combination. Approaches other than serum assay alone will be needed to detect all malignant pelvic masses at an early stage.

Antigens, Neoplasm

Microchromosomal assignment of the chicken ovotransferrin and adenylate kinase genes.

Ovotransferrin, an egg-white protein implicated in the transfer of trace elements from the hen oviduct to the developing avian embryo, and cytosolic adenylate kinase, an essential enzyme involved in the interconversion of adenine nucleotides in energetically active tissues, have been mapped to two separate chicken microchromosomes by fluorescent in situ hybridization. Considering present and previous data, the possibility of loss of intron material resulting in the compactation of genes in chicken microchromosomes is briefly discussed.

Adenylate Kinase

[Immunohistochemical study of proliferating cell nuclear antigen (PCNA) in gynecological tumors and their related lesions].

We have investigated whether monoclonal antibody (PC10) of proliferating cell nuclear antigen (PCNA) could be useful as a marker of proliferating cells within formalin-fixed, paraffin-embedded tissue sections of 140 gynecological tumors and their related lesions. There was a positive correlation (r = 0.76) between the labelling index for PCNA and that for Ki67. Immunohistochemical staining for PC10 was confined to the nucleus and showed a diffuse or granular pattern or a mixture of both. The distribution of PC10 staining in non-neoplastic tissues was localized to proliferating cell compartments. In malignant tissues, the localization of the distribution of PCNA-positive cells came to be lost and the proportion of positive cells varied from case to case as well as from field to field within the same tissue section. The cases in which more than 31% of cells were positive for PCNA were as follows: Cervical squamous dysplasia 2/3, squamous carcinoma in situ 2/5, microinvasive squamous carcinoma 2/2, invasive squamous carcinoma 9/13, adenocarcinoma in situ 4/4, microinvasive adenocarcinoma 3/3, invasive adenocarcinoma 6/7, endometrial adenocarcinoma 6/25, ovarian epithelial malignant tumors 11/17, sex cord stromal tumors 2/14, and germ cell tumors 3/22. It is concluded that immunohistochemical staining for PC10 may be useful as a marker for proliferating activity of the cells both in normal and tumor tissues rather than for malignancy.

Antigens, Neoplasm

Progressive facial hemiatrophy with localized scleroderma.

A 46-year-old woman who presented with progressive facial hemiatrophy (PFH) following localized scleroderma is described. The patient had a markedly deformed and depressed plaque surrounded by erythema on the right cheek. She also showed linear scleroderma with hair loss on the occipital area and morphea lesions on the neck and shoulder. Histological findings of the facial and other atrophic lesions were consistent with localized scleroderma. Therefore, the PFH and localized scleroderma may have had the same pathological background in this case.

Facial Hemiatrophy

Cloning and characterization of the gene encoding bovine mitochondrial adenylate kinase isozyme 3.

The structure of the gene (AK3) encoding bovine mitochondrial (mt) adenylate kinase isozyme 3 (AK3) has been determined. The gene spans about 46 kb and splits into five exons. The 5'-flanking region of the gene lacks typical transcriptional regulatory elements such as TATA and CAAT boxes. The G + C content of this region is high (71%), and seven GC boxes are recognized. Possible sequences responsive to transcription factors, AP-1, AP-2, Myf-6 and MyoD1, are present in this region. In the 5'-flanking region, there are sequences (mt sequence) which were found in the genes encoding other mt proteins. Transcriptional mapping analyses revealed one major mRNA start point. The promoter activity measurement in Chinese hamster ovary cells by transient expression of the cat gene connected with the 5'-flanking region, showed presence of a functional promoter.

Adenylate Kinase

Synthesis and accumulation of thiamin triphosphate in Escherichia coli cells expressing chicken cytosolic adenylate kinase.

To examine whether cytosolic adenylate kinase (AK1, EC 2.7.4.3) catalyzes synthesis of thiamin triphosphate (TTP) in vivo, chicken AK1 was expressed in Escherichia coli, and cellular AK1 activity and TTP content were determined. E. coli harboring the vector plasmid was used as a control. Chicken AK1 was expressed in the producer strain at a high level (83 U/mg protein) even without inducers, and this expression was doubled (153 U/mg protein) by beta-D-isopropylthiogalactopyranoside (IPTG). TTP was accumulated in the producer cells at a high level (5.7 nmol/g dry weight) without IPTG and this was also doubled (10.2 nmol/g dry weight) by IPTG. TTP content in the control strain was very low (0.2-0.9 nmol/g dry weight) and was unaffected by IPTG. Neither bacterial growth curve nor cellular content of AMP, ADP, ATP, thiamin diphosphate or total thiamin (sum of thiamin and its phosphate esters) was different between the producer and the control strains. These results indicate that chicken AK1 expressed in E. coli catalyzed the synthesis and accumulation of TTP within the bacterial cells.

Adenosine Diphosphate

Structural analyses of a channel-forming fragment of colicin E1 incorporated into lipid vesicles. Fourier-transform infrared and tryptophan fluorescence studies.

Structural changes upon binding to the membrane of a COOH-terminal channel-forming thermolytic fragment of colicin E1 have been studied by means of a variety of spectroscopic techniques. Circular dichroism measurements show that the thermolytic fragment predominantly takes a helical structure in aqueous and detergent solutions. Fourier transform infrared spectroscopic measurements indicate that the content of the beta-structure is significantly increased when the thermolytic fragment is bound to vesicles. On the basis of the result of tryptophan fluorescence measurements, we have concluded that each of the three tryptophan residues of the thermolytic fragment exists in different environments, i.e. one is buried in the lipid bilayer, one exists on the cis side of the vesicles, and one exists near the surface of the lipid bilayer. The Fourier transform infrared and fluorescence data have been used along with the crystal structure of colicin A, which is highly homologous to colicin E1 in structure and function, to propose a model of the thermolytic fragment bound to the lipid vesicles.

Amino Acid Sequence

Characterization of a processed pseudogene derived from the gene encoding bovine adenylate kinase isozyme 2.

We have isolated an intronless processed pseudogene for an isoform of bovine adenylate kinase isozyme 2 (AK2B). The pseudogene which was flanked by 11-nucleotide (nt) direct repeats contained an open reading frame of 519 bp which encodes 173 amino acids (aa), 61 aa shorter than AK2B. In the entire pseudogene sequence, substitutions as well as deletions and insertions were noted in 78 nt positions as compared with the AK2B cDNA (95.1% homology). Northern-blot analysis showed that this pseudogene was not expressed in bovine tissues.

Adenylate Kinase

Detection of human papillomavirus type 16 in sexual partners of patients having cervical cancer by polymerase chain reaction.

The polymerase chain reaction (PCR) was employed to detect human papillomavirus (HPV) 16 and 18 in cytological samples from the uterine cervix and in urine samples from the male consorts. HPV 16 was detected in 2 (25%) of 8 males whose wives were positive for HPV 16, while it was detected in only one (7%) of 14 consorts whose wives were negative for HPV 16 and 18. This is the first report of the detection of HPV 16 in urine. Viral detection in urine samples by the PCR method is a non-invasive, convenient and useful tool for large-scale epidemiologic studies and investigations of the mechanism of virus transmission.

Adenocarcinoma

[Detection of HPV DNA in the uterine cervical lesions by polymerase chain reaction and in situ hybridization].

Human papillomavirus (HPV) is found in close association with carcinogenesis of the uterine cervix. We applied a new in vitro gene amplification technology, the polymerase chain reaction (PCR) to detect HPV 16 and 18 in cervical exfoliated cells. HPV infections were detected in 5 (16%) of 31 women with no pathological lesions of the uterine cervix (normal), 16 (24%) of 67 with cervical intraepithelial neoplasia (CIN) and 6 (38%) of 16 with invasive cervical cancer. Moreover, 10% formalin-fixed and paraffin-embedded tissue sections were prepared from the uterine cervix of these 27 women with PCR-proven HPV infection and were examined for the histological localization of HPV-DNA by in situ hybridization with biotin-labeled DNA probes of HPV types 6/11, 16/18 and 31/33/35. HPV-DNA type 16/18 was detected in 3 of 5 normal women, 2 of 4 CINs I, 2 of 3 CINs II, 6 of 9 CINs III and 6 of 6 invasive cervical cancers. HPV-DNA type 6/11 was detected in 6 of 6 condylomas. Viral DNA sequence was detected in the superficial cells of CIN I and II, and it was distributed through entire thickness layer of undifferentiated cells derived from CIN III and squamous cell carcinoma. In addition, the staining intensity became weak as the lesion progressed. These differences between lesions might be due to the difference in the viral form in the nuclei, ie whether an episomal or integrated form. Thus, an in situ hybridization technique with a biotin-labeled DNA probe as well as the PCR method is useful for the detection of HPV in clinical samples.

Base Sequence

[Alcohol-induced variant angina and considerations of its mechanism: a case report].

A 64-year-old man had episodes of angina pectoris several hours after ingestion of alcohol. Otherwise, anginal attacks never occurred. He was diagnosed as having variant angina based on the typical ST elevation in leads II, III and aVF during the anginal attacks. We performed an alcohol challenge test on his 4th admission day. He was given 540 ml of "sake" at 6:00 p.m. and anginal attacks with ST elevations occurred 9.5 hours after its ingestion. The peak value of plasma ethanol was 136 mg/dl at 9:00 p.m. and it returned to 0 when angina occurred. By alcohol ingestion, urinary excretion of Mg increased in association with a slight decrease in serum Mg. The ratio of serum Ca to Mg was increased from 4.0 at the control state before taking alcohol to 4.5 at the occurrence of anginal attack. Mg content in red blood cells and in plasma catecholamines did not differ between before and after ingesting alcohol. We concluded that the change in the extracellular Ca-Mg equilibrium may contribute to the mechanism of alcohol-induced variant angina.

Aged

Mechanism of adenylate kinase. Critical evaluation of the X-ray model and assignment of the AMP site.

The substrate binding sites of adenylate kinase (AK) proposed by X-ray crystallographic studies [Pai, E. F., Sachsenheimer, W., Schirmer, R. H., & Schulz, G. E. (1977) J. Mol. Biol. 114, 37-45, and subsequent revisions] were evaluated by site-specific mutagenesis in conjunction with structural analysis by NMR. The residues examined in this report include two near an adenosine site (threonine-39 and arginine-44) and two in the phosphate binding region (arginine-128 and arginine-149). The results and conclusions are summarized as follows: (a) Although Thr-39 is very close to an adenine site [Egner, U., Tomasselli, A. G., & Schulz, G. E. (1987) J. Mol. Biol. 195, 649-658], it is nonessential either structurally or functionally. (b) The R44M mutant enzyme showed significant increases in the Michaelis and dissociation constants of adenosine 5'-monophosphate (AMP) (36- and 22-fold, respectively) while all other kinetic parameters were relatively unperturbed. The proton NMR property of this mutant was unchanged in the free enzyme and only slightly perturbed in the binary complexes with AMP and with MgATP (adenosine 5'-triphosphate), and in the ternary complex with MgAP5A [P1,P5-bis(5'-adenosyl) pentaphosphate]. These results indicate that Arg-44 interacts specifically with AMP starting at the binary complex, and suggest that the MgATP site proposed by Pai et al. (1977) is likely to be the AMP site. (c) The kinetic parameters of R149M were dramatically perturbed: kcat decreased by a factor of 1540, Km increased to 130-fold, and kcat/Km decreased by a factor of 2 X 10(5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Monophosphate

Upstream regulatory sequence for transcriptional activator XylR in the first operon of xylene metabolism on the TOL plasmid.

Transcription of the first operon coding for m-xylene-degrading enzymes on the TOL plasmid of Pseudomonas putida is activated by the xylR gene product in the presence of m-xylene. The operon has the consensus sequence of the ntr/nif promoters at -24 and -12 regions, and the transcription is dependent on an RNA polymerase containing a sigma factor NtrA (RpoN or sigma 54). Deletion derivatives of the upstream sequence of the operon promoter were made in vitro and connected with the xylE gene on a plasmid. Their promoter activities were analyzed in Escherichia coli by monitoring catechol 2,3-dioxygenase activity, the xylE gene product. A cis-acting DNA element was identified, which is required for activation of the operon promoter by XylR protein in the presence of the inducer. This regulatory sequence of about 40 base-pairs in length was located 150 base-pairs upstream from the transcription start site. Analysis of the mutants containing insertions between the upstream regulatory sequence and the promoter sequence demonstrated strong dependence of the activation upon helical periodicity of DNA. The regulatory sequence functioned in the inverse orientation or at a distance of more than 1 x 10(3) base-pairs upstream from the promoter though less efficient. These results indicated that this upstream regulatory sequence might be the binding site for XylR protein. DNA-loop formation through protein-protein interaction between XylR protein attached to the upstream sequence and the NtrA-containing RNA polymerase bound by the promoter sequence was suggested for activation of the operon transcription. A sequence similar to the regulatory sequence of the first operon of xylene metabolism was found in the upstream region of the xylS gene, which is also activated by XylR protein in the presence of m-xylene.

Base Sequence

Isolation and characterization of the gene encoding bovine adenylate kinase isozyme 2.

Mitochondrial adenylate kinase isozyme 2 (AK2) exists in two isoforms, AK2A and AK2B, which have the same amino-acid sequence except for the C-terminal portion. We have isolated the gene encoding AK2 from a bovine genomic library. The gene covers about 25 kb and consists of seven exons and six introns. The nucleotide sequences from exon 1 to the 5' half of exon 6 encode the portion common to AK2A and AK2B, while the sequences of the 3' half of exon 6 and exon 7 direct the unique portions of AK2A and AK2B, respectively. Therefore, an alternative splicing mechanism is suggested in generating two types of mRNA encoding AK2A and AK2B. The 5'-flanking region of the gene lacks a TATA box, but contains three CAAT boxes. The G + C content of this region is high and eight copies of GC box are found. These features of the promoter region resemble those of 'housekeeping' genes. S1 mapping and primer extension analyses revealed multiple transcription start points. The 581-bp region just upstream from the start codon functions as a promoter in the expression of the cat gene in Chinese hamster ovary cells.

Adenylate Kinase