Cell-specific hypomethylation of the pepsinogen gene in pepsinogen-producing cells

The pepsinogen gene is hypomethylated in the stomach, in which it is expressed. For demonstration that this hypomethylation of the pepsinogen gene in the stomach reflects pepsinogen-producing cells, we analyzed fractions of dispersed mucosal cells with various contents of pepsinogen-producing cells prepared from guinea pig stomach by centrifugal elutriation. mRNA expression and the extent of hypomethylation of the pepsinogen gene in each fraction was closely correlated with the content of pepsinogen-producing cells. These results suggested hypomethylation of the pepsinogen gene in pepsinogen-producing cells and differential pepsinogen gene methylation in cell subpopulations in the stomach.     

Mutagenicity of 4-nitroquinoline 1-oxide in the MutaMouse.

As part of a collaborative study, the Mammalian Mutagenesis Study Group (MMS), a sub-organization of the Environmental Mutagen Society of Japan (JEMS) conducted mutagenicity tests in MutaMouse. Using a positive selection method, we studied the organ-specificity and time dependence of mutation induction by 4-nitroquinoline 1-oxide (4NQO). A single dose of 4NQO was administered intraperitoneally (7.5 or 15 mg/kg) or orally (200 mg/kg) to groups of male mice. On days 7, 14 and 28 after treatment, we isolated the liver, kidney, lung, spleen, bone marrow, testis and stomach in the intraperitoneal administration experiment and the liver, lung, bone marrow, testis and stomach in the oral administration experiment. In addition, we performed the peripheral blood micronucleus test to evaluate clastogenicity. In the mice treated intraperitoneally at 7.5 mg/kg, we found increased mutant frequency (MF) only in the lung, where the MF did not vary with expression time. In the mice treated at 15 mg/kg, we found increased MF in the liver, bone marrow and lung. In orally treated mice, the MF was high in the lung and liver and very high in the bone marrow and stomach while the increase in the testis was negligible. As the expression time was prolonged, the MF tended to increase in the liver, decrease in the bone marrow, and remain stable in the lung, testis and stomach. The incidence of micronucleus induction in peripheral blood cells was significantly increased (p<0.01) in the 4NQO groups when compared with the vehicle control group by intraperitoneal treatment. Thus, these assay systems appeared to be of use in detecting not only genetic mutation but also chromosomal aberration.     

The Structures of Cirratiomycin A and B,the New Peptide Antibiotics

The structures of cirratiomycin A and B have been elucidated by a degradative study and ¹H-and ¹³C-NMR spectral analysis. It is revealed here that cirratiomycin A and B are heptapeptides containing three unusual new amino acids, viz, hydroxymethylserine, 2,3,4,5-tetrahydropyridazine-3-carboxylic acid and 2,3-didehydroisoleucine.     

Clustering of the trp genes in Burkholderia (formerly Pseudomonas) cepacia

Abstract Chromosomal location of trp genes of a strain Burkholderia cepacia (formerly Pseudomonas cepacia ) has been determined by transduction using a generalized transducing phage CP75 and by molecular analysis for a cosmid plasmid clone with trp genes isolated from the genomic gene library of the strain. The trp genes were classified into three linkage groups and they all were closely linked on a short chromosomal region probably in the order ( trpA, trpB, trpF)-(trpC, trpD)-trpE .     

Perinatal changes in amylase and serum corticosterone levels in rats

In rats amylase activity in the pancreas increased greatly from day 15 of gestation to a maximum on day 21. Then it decreased to less than one-tenth of this maximum value on about day 5 after birth. It increased again about 15 days after birth and reached the adult level about 30 days after birth.No amylase activity was in the parotid gland before birth: it appeared about 12 days after birth and reached the adult level, which was higher than that in the pancreas, about 30 days after birth.The serum corticosterone level was as high as the adult level before birth. Then it decreased to less than one-tenth of the adult level 5 days after birth and increased again from 15 to 25 days after birth to the adult level. The developmental change in the serum corticosterone level seemed to influence amylase activity in the pancreas both before and after birth, and that in the parotid gland only after birth.The serum contained both pancreatic and paratoid type isozymes of amylase until 1 day after birth but only the parotid type from 3 days after birth.     

Detection of Merkel cell polyomavirus in cervical squamous cell carcinomas and adenocarcinomas from Japanese patients

ABSTRACT: BACKGROUND: Merkel cell polyomavirus (MCPyV) was identified originally in Merkel cell carcinoma (MCC), a rare form of human skin neuroendocrine carcinoma. Evidence of MCPyV existence in other forms of malignancy such as cutaneous squamous cell carcinomas (SCCs) is growing. Cervical cancers became the focus of our interest in searching for potentially MCPyV-related tumors because: (i) the major histological type of cervical cancer is the SCC; (ii) the uterine cervix is a common site of neuroendocrine carcinomas histologically similar to MCCs; and (iii) MCPyV might be transmitted during sexual interaction as demonstrated for human papillomavirus (HPV). In this study, we aimed to clarify the possible presence of MCPyV in cervical SCCs from Japanese patients. Cervical adenocarcinomas (ACs) were also studied. RESULTS: Formalin-fixed paraffin-embedded tissue samples from 48 cervical SCCs and 16 cervical ACs were examined for the presence of the MCPyV genome by polymerase chain reaction (PCR) and sequencing analyses. PCR analysis revealed that 9/48 cervical SCCs (19 %) and 4/16 cervical ACs (25 %) were positive for MCPyV DNA. MCPyV-specific PCR products were sequenced to compare them with reference sequences. The nucleotide sequences in the MCPyV large-T (LT)-sequenced region were the same among MCPyV-positive cervical SCCs and AC. Conversely, in the MCPyV viral protein 1 (VP1)-sequenced, two cervical SCCs and three cervical ACs showed several nucleotide substitutions, of which three caused amino acid substitutions. These sequencing results suggested that three MCPyV variants of the VP1 were identified in our cases. Immunohistochemistry showed that the LT antigen was expressed in tumor cells in MCPyV-positive samples. Genotyping of human HPV in the MCPyV-positive samples revealed that infected HPVs were HPV types 16, 31 and 58 for SCCs and HPV types 16 and 18 for ACs. CONCLUSIONS: This study provides the first observation that MCPyV coexists in a subset of HPV-associated cervical cancers from Japanese patients. The prevalence of MCPyV in these lesions was close to that observed in the cutaneous SCCs. Further worldwide epidemiological surveys are warranted to determine the possible association of MCPyV with pathogenesis of cervical cancers.     

Glycolytic intermediates induce amorphous calcium carbonate formation in crustaceans

It has been thought that phosphorus in biominerals made of amorphous calcium carbonate (ACC) might be related to ACC formation, but no such phosphorus-containing compounds have ever been identified. Crustaceans use ACC biominerals in exoskeleton and gastroliths so that they will have easy access to calcium carbonate inside the body before and after molting. We have identified phosphoenolpyruvate and 3-phosphoglycerate, intermediates of the glycolytic pathway, in exoskeleton and gastroliths and found them important for stabilizing ACC.     

Transgenic mouse model of cutaneous adnexal tumors

TMEM207 was first characterized as being an important molecule for the invasion activity of gastric signet-ring cell carcinoma cells. In order to unravel the pathological properties of TMEM207, we generated several transgenic mouse lines, designated C57BL/6-Tg (ITF-TMEM207), in which murine TMEM207 was ectopically expressed under a truncated (by ~200 bp) proximal promoter of the murine intestinal trefoil factor (ITF) gene (also known as Tff3). Unexpectedly, a C57BL/6-Tg (ITF-TMEM207) mouse line exhibited a high incidence of spontaneous intradermal tumors with histopathological features that resembled those of various human cutaneous adnexal tumors. These tumors were found in ~14% female and 13% of male 6- to 12-month-old mice. TMEM207 immunoreactivity was found in hair follicle bulge cells in non-tumorous skin, as well as in cutaneous adnexal tumors of the transgenic mouse. The ITF-TMEM207 construct in this line appeared to be inserted to a major satellite repeat sequence at chromosome 2, in which no definite coding molecule was found. In addition, we also observed cutaneous adnexal tumors in three other C57BL/6-Tg (ITF-TMEM207) transgenic mouse lines. We believe that the C57BL/6-Tg (ITF-TMEM207) mouse might be a useful model to understand human cutaneous adnexal tumors.KEY WORDS: Cutaneous adnexal tumor, Mouse model, TMEM207     

Remodeling of the Rad51 DNA Strand-Exchange Protein by the Srs2 Helicase

Homologous recombination is associated with the dynamic assembly and disassembly of DNA–protein complexes. Assembly of a nucleoprotein filament comprising ssDNA and the RecA homolog, Rad51, is a key step required for homology search during recombination. The budding yeast Srs2 DNA translocase is known to dismantle Rad51 filament in vitro. However, there is limited evidence to support the dismantling activity of Srs2 in vivo. Here, we show that Srs2 indeed disrupts Rad51-containing complexes from chromosomes during meiosis. Overexpression of Srs2 during the meiotic prophase impairs meiotic recombination and removes Rad51 from meiotic chromosomes. This dismantling activity is specific for Rad51, as Srs2 Overexpression does not remove Dmc1 (a meiosis-specific Rad51 homolog), Rad52 (a Rad51 mediator), or replication protein A (RPA; a single-stranded DNA-binding protein). Rather, RPA replaces Rad51 under these conditions. A mutant Srs2 lacking helicase activity cannot remove Rad51 from meiotic chromosomes. Interestingly, the Rad51-binding domain of Srs2, which is critical for Rad51-dismantling activity in vitro, is not essential for this activity in vivo. Our results suggest that a precise level of Srs2, in the form of the Srs2 translocase, is required to appropriately regulate the Rad51 nucleoprotein filament dynamics during meiosis.     

Capoamycin,a New Isotetracenone Antibiotic

A new antibiotic was obtained from the cultured broth of an actinomycete identified as Streptomyces capoamus, and has been named capoamycin. The structure of capoamycin was elucidated by NMR spectral analysis and chemical degradation, which revealed that capoamycin was composed of a modified benz[a]anthraquinone chromophore, a β-C-olivoside and (E,E)-2,4- decadienoic acid. Capoamycin inhibited the growth of Gram-positive bacteria, yeasts and fungi, induced differentiation of mouse myeloid leukemia cells (M1) and prolonged the survival periods of mice bearing Ehrlich ascites carcinoma.