Occurrence of natural triploidy in Rhamdia quelen (Siluriformes, Heptapteridae).

Five specimens of Rhamdia quelen collected from the Lindóia Stream, PR, Brazil, were cytogenetically analyzed. The diploid chromosome number found was 58, including 30 metacentric, 16 submetacentric, 10 subtelocentric, and 2 acrocentric chromosomes. Supernumerary or B chromosomes, frequently observed in this fish group, were not detected. One of the individuals was triploid, with 3n = 87. A silver-stained nucleolar organizer region was found on a pair of submetacentric chromosomes of the diploid specimens, and on three chromosomes of the triploid individual, confirming triploidy. Treatment with fluorochrome chromomycin A(3) revealed fluorescent bands coincident with those of the silver-stained nucleolar organizer region, in both diploid and triploid individuals, showing that this is a GC-rich region. Heterochromatin distribution was visualized by the C-banding technique, mainly in the terminal chromosome regions of the individuals and was also observed in the pericentromeric regions of some chromosomes and at both telomeres.

Characterization and overproduction of EcoO109I methyltransferase.

In order to characterize EcoO109I methyltransferase, a recombinant Escherichia coli clone that overproduces the enzyme was constructed. The coding region of M.EcoO109I was joined to the lac promoter of an expression vector, pUC118, and the resulting plasmid was introduced into E. coli HB101. M.EcoO109I was purified homogeneously from IPTG-induced cells, and was found to consist of a monomer subunit. M.EcoO109I uniquely methylates the inner deoxycytidylate residue in the sequence 5'-(A/G)GGNCC(C/T)-3' to produce 5-methylcytosine. The enzyme was most active at pH 8.0-8.5 and 50 degrees C. The enzyme activity was not affected by the addition of Mg2+ or EDTA.

Evidence of horizontal transfer of the EcoO109I restriction-modification gene to Escherichia coli chromosomal DNA.

A DNA fragment carrying the genes coding for EcoO109I endonuclease and EcoO109I methylase, which recognize the nucleotide sequence 5'-(A/G)GGNCC(C/T)-3', was cloned from the chromosomal DNA of Escherichia coli H709c. The EcoO109I restriction-modification (R-M) system was found to be inserted between the int and psu genes from satellite bacteriophage P4, which were lysogenized in the chromosome at the P4 phage attachment site of the corresponding leuX gene observed in E. coli K-12 chromosomal DNA. The sid gene of the prophage was inactivated by insertion of one copy of IS21. These findings may shed light on the horizontal transfer and stable maintenance of the R-M system.

Characterization of high- and low-molecular weight zinc-dependent acid phosphatases in bovine liver.

We have purified two forms of Zn2+-dependent acid phosphatase (Zn2+-APase) from bovine liver, both of which require Zn2+ to hydrolyze the substrate p-nitrophenyl phosphate in an acidic environment. The apparent molecular weights of these two forms of Zn2+-APase were estimated to be about 100,000 and 62,000 by gel filtration, and about 44,000 and 31,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, respectively. The low-molecular weight (LMW) Zn2+-APase catalyzed the hydrolysis of myo-inositol-1-phosphate in the presence of 3 mM Mg2+ at physiological pH, but the high-molecular weight (HMW) enzyme did not. The LMW-Zn2+-APase of bovine liver was recognized by polyclonal antibodies developed against the Zn2+-APase of bovine brain, but the HMW-Zn2+-APase was not.

myo-Inositol monophosphatase in the brain has zinc ion-dependent tyrosine phosphatase activity.

1. myo-Inositol monophosphatase (E.C. 3.1.3.25) hydrolyzes inositol monophosphate to form free myo-inositol, the precursor for the inositol phospholipid second-messenger signaling systems. The biochemical properties of the enzyme were examined in detail. 2. The enzyme exhibited significant hydrolytic activity only on phosphotyrosine among physiological substrates tested in the presence of Zn2+ ions in an acidic environment. 3. The enzyme was recognized and immunoprecipitated with polyclonal antibodies developed against the Zn2+-dependent tyrosine phosphatase of bovine brain. 4. These results indicate that myo-inositol monophosphatase exhibits Zn2+-dependent tyrosine phosphatase activity in an acidic environment and has immunological identity with a Zn2+-dependent tyrosine phosphatase.

Alteration of myo-inositol monophosphatase in Alzheimer's disease brains.

myo-Inositol monophosphatase (E.C.3.1.3.25) catalyzes the hydrolysis of myo-inositol 1-phosphate in the presence of Mg2+ at a physiologic pH to form free myo-inositol, maintaining a supply that represents the precursor for inositol phospholipid second messenger signaling systems. In the present study the activity and protein level of myo-inositol monophosphatase were investigated in samples from normal human and Alzheimer's disease (AD) postmortem brains. The separation profile on Sephadex G-100 gel filtration chromatography revealed one major form of myo-inositol monophosphatase in crude extracts from both normal human and AD brains. In AD brains myo-inositol monophosphatase activity and its protein level were significantly higher than in control brains. The activity of myo-inositol monophosphatase per enzyme molecule was similar in control and AD brains. These results suggest that myo-inositol monophosphatase is upregulated in AD, probably reflecting compensatory mechanisms concerned with phospholipid metabolism.

Zinc-ion-dependent acid phosphatase exhibits magnesium-ion-dependent myo-inositol-1-phosphatase activity.

We have purified bovine brain Zn(2+)-dependent acid phosphatase (Zn(2+)-APase), which requires Zn2+ ions to hydrolyze the substrate p-nitrophenyl phosphate (pNPP) in an acidic environment. The substrate specificity and metal requirement of Zn(2+)-APase at a physiological pH was also studied. The enzyme exhibited hydrolytic activity on myo-inositol-1- and -2-monophosphates, 2'-adenosine monophosphate, 2'-guanosine monophosphate, and the alpha- and beta-glycerophosphates, glucose-1-phosphate, and fructose-6-phosphate in 50 mM Tris-HCl buffer (pH 7.4) in the presence of Mg2+ ions, but not on pNPP and phosphotyrosine. Zn2+, Mn2+ and Co2+ ions were less effective for activation. Among the above substrates, myo-inositol-1-phosphate was the most susceptible to hydrolysis by the enzyme in the presence of 3 mM Mg2+ ions. The enzyme exhibited an optimum pH at around 8 for myo-inositol-1-phosphate in the presence of 3 mM Mg2+ ions. The Mg(2+)-dependent myo-inositol-1-phosphatase activity of the enzyme was significantly inhibited by Li+ ions. The Zn(2+)-dependent p-nitrophenyl phosphatase activity and Mg(2+)-dependent myo-inositol-1-phosphatase activity of the purified enzyme fraction exhibited similar behavior on Sephadex G-100 and Mono Q colomns. These findings suggest that Zn(2+)-APase also exhibits Mg(2+)-dependent myo-inositol-1-phosphatase activity under physiological conditions.

[Study of early gastric carcinomas with a pyloric stenosis].

From 1969 to 1989, 1106 cases of early gastric carcinomas were treated in our hospital, and 9 cases (0.8%) of an early gastric carcinoma with a pyloric stenosis were found among them. Five of these cases involved males and 4 cases females. The average age of these patients was 57.1 years. An accurate preoperative diagnosis was very difficult and 7 cases had been considered to be advanced gastric carcinoma preoperatively. In all these cases the lesions were found located on the pyloric ring or in the antral region. Further, all cases evidenced a submucosal infiltration and/or ulceration in the lesion. Most of the stenotic cases had lesions greater than 3.1 cm in diameter, with diameters of over 1.1 cm in the ulceration and the submucosal infiltration. Some early gastric carcinomas in the antral region with no pyloric stenosis also had lesions that were over this size.

[A clinicopathological study of early mucinous adenocarcinoma of the stomach].

From 1963 to 1986, 1126 cases (1300 lesions) of early gastric carcinoma were treated at Fukui Prefectural Hospital. Mucinous adenocarcinomas comprised 16 lesions in this series. These cases of mucinous adenocarcinoma were younger than all the other early carcinomas of the stomach and they often were locted in the lower third of the stomach. Macroscopically, most were types "Iia + IIc". Dividing them into 3 grouping: papillary, tubular, and signet ring cell types, depending on the microscopic appearance of the intramucosal carcinoma, the signet ring cell group differed from the other two as to age, macroscopic appearance, and region it occupied. An immunochemical study showed that CA19-9 stained positively in a mucous lake, much like a carcinoma cell, but that CEA stained little.

[Early carcinoma of the gastric remnant: pathological features relating to the interval between the initial and second surgery].

Twenty cases of early carcinoma of the gastric remnant have been treated at our hospital and examined clinico-pathologically. In 11 cases, the interval after the initial gastrectomy, due to the gastric carcinoma, was done was short compared with length of the interval of 9 cases after a gastrectomy for a benign gastric disease. There were two types of gastric remnant carcinomas in cases in which the interval extended 10 years. The first type developed at the site of the gastro-intestinal anastomosis, especially when the anastomosis was found to be joined by the Billroth II method, and the carcinoma was associated with a gastritis cystica polyposa (GCP). The other type showed a polypoid appearance except for the stomal site.

Development of a heart disease screening system for school children and its results in the Tokyo area in 1980.

After the revision of the School Health Law in Japan the systems for heart disease screening for school children showed a great advance and the computerized devices for automatic evaluation of selected leads ECG and PCG were developed rapidly and have been improved in Japan. Two systems of heart disease screening for school children have been developed, that is, the Tokyo system and the "ECG-PCG for all children system". The Tokyo system utilizes a questionnaire, a physical examination by school physicians and a chest X-ray for the primary screening procedure and ECG-PCG for the secondary procedure. The "ECG-PCG for all children system" utilizes a questionnaire, a chest X-ray and ECG-PCG. The superiority of the ECG-PCG system was shown in comparison with the Tokyo system. Nearly twice as many cases of congenital heart disease were detected by the ECG-PCG system as compared with the Tokyo system, and many cases were disclosed for the first time. The "ECG-PCG for all children system" will probably be more popular in the near future in accordance with the advance of computerized systems.