Formation of Hydrogen Peroxide by NAD(P)H Oxidation with Isolated Cell Wall-Associated Peroxidase from Cultured Liverwort Cells, Marchantia polymorpha L.

Hydrogen peroxide was formed in isolated cell walls from Marchantiapolymorpha L. in the presence of MnCl₂ by either NADH or NADPHoxidation. This reaction was stimulated by phenols such as 2,4-dichlorophenolor p-coumarate, suggesting a reaction similar to that proposedfor the last step of lignification in higher plant cells, althoughbryophytes have been reported to be devoid of lignin. (Received June 16, 1987; Accepted March 3, 1987)     

Intramolecular disulfide linked alphabeta and alphaalpha in oxidized tropomyosin: separation, identification, and process of formation

The oxidation of rabbit skeletal tropomyosin (TM) by repeated cycles of freezing and melting in 0.3 mM Na bicarbonate was studied by electrophoresis and column chromatography. The oxidized TM showed two bands at ca. 70,000 daltons on sodium dodecyl sulfate (SDS)-polyacrylamide gels. Each band component was separated into disulfide-linked alphabeta and alphaalpha by carboxymethyl cellulose (CMC) column chromatography in urea. Oxidized TM before fractionation, as well as the alphabeta and alphaalpha components, was found to have a molecular weight of about 80,000 daltons, indicating the disulfide bonds to be primarily intramolecular. Oxidation of dilute TM in 1 M NaCl by exposure to air also produced disulfide-linked alphabeta. Partially oxidized TM was found to separate into beta, alphabeta, alpha, and alphaalpha on CMC chromatography, and these were eluted with a linear gradient of NaCl at molarities of ca. 0.09, 0.11, 0.12, and 0.14 M, respectively. The oxidation process was investigated by CMC chromatography, and a possible mechanism is presented. The alphabeta and alphaalpha components may exist as dominant component in TM in vitro rather than as a random mixture of two subunits. A splitting of the electrophoretic band of the alpha subunit into a doublet was observed.     

Ultrasonic absorption in aqueous solution of lysozyme.

The titration curve of ultrasonic absorption at 2.82 MHz in aqueous solutions of lysozyme measured by Zana and Lang [J. Phys. Chem., 74 , 2734 (1970)] is theoretically analyzed. The maxima at pH 3 and pH 11 are describable with proton-transfer reactions of dissociable carboxyl and amino groups by assuming that volume changes due to the reactions are 2.3 and 5.2 cm³/mole, respectively, which are appreciably smaller than those of simple amino acids. The remaining, pH-independent excess absorption over solvent is measured at frequencies ranging from 3 to 150 MHz. The absorption is ascribed to the internal loss of protein. The complex compressibility β′_p ? iβ″_p of lysozyme molecule is evaluated as β′_p = 7.2 × 10^?12 cm²/dyne and β″_P = 4.3 × 10^?14 cm²/dyne from the increments over solvent in absorption as well as in sound velocity.     

miR‐197 induces epithelial–mesenchymal transition in pancreatic cancer cells by targeting p120 catenin

Invasive ductal adenocarcinoma (IDA) of the pancreas manifests poor prognosis due to the early invasion and distant metastasis. In contrast, intraductal papillary mucinous adenoma or carcinoma (IPMA or IPMC) reveals better clinical outcomes. Various molecular mechanisms contribute to these differences but entire picture is still unclear. Recent researches emphasized the important role of miRNA in biological processes including cancer invasion and metastasis. We previously described that miR‐126 is down‐regulated in IDA compared with IPMA or IPMC, and miR‐126 regulates the expression of invasion related molecule disintegrin and metalloproteinase domain‐containing protein 9 (ADAM9). Assessing the difference of miRNA expression profiles of IDA, IPMA, and IPMC, we newly identified miR‐197 as an up‐regulated miRNA specifically in IDA. Expression of miR‐197 in pancreatic cancer cells resulted in the induction of epithelial–mesenchymal transition (EMT) along with the down‐regulation of p120 catenin which is a putative target of miR‐197. Direct interaction between miR‐197 and p120 catenin mRNA sequence was confirmed by 3′UTR assay, and knockdown of p120 catenin recapitulated EMT induction in pancreatic cancer cells. In situ hybridization of miR‐197 and immunohistochemistry of p120 catenin showed mutually exclusive patterns suggesting pivotal role of miR‐197 in the regulation of p120 catenin. This miR‐197/p120 catenin axis could be a novel therapeutic target. J. Cell. Physiol. 228: 1255–1263, 2013. © 2012 Wiley Periodicals, Inc.     

Prolonged diapause of specialist seed-feeders makes predator satiation unstable in masting of<Emphasis Type="Italic"> Quercus crispula</Emphasis>

Quercus crispula (=Q. mongolica var. grosseserrata) is the predominant tree species in cool temperate, mixed broadleaf/conifer forests in northern Japan. We compared 11 years of data on acorn production in a population of Q. crispula, with data on seed-insect populations, to try to answer the following questions: (1) Does Q. crispula show a regular pattern of masting? (2) How long do principal seed predators remain in diapause? (3) How do the seed predators affect the pattern of predator satiation? Q. crispula showed a tendency to alternate bearing, with significant synchrony between individual trees. The principal acorn-feeding insects (Curculio spp. weevils), which infested 25%–70% of matured acorns, generally exhibited a prolonged diapause of 2 years. No significant negative relationship was found between the rate of injury by the weevils and the density of mature acorns, indicating that simple predator satiation fails due to the synchrony of the life-cycle of acorn-feeding insects and the periodical production of acorns. However, the rate of injury by the weevils was negatively correlated with the relative abundance of mature acorns to the number of weevil larvae that had matured 2 years previously. Thus, the proportion of sound acorns notably increased in a rich crop after a disturbance in alternate bearing. Prolonged diapause of specific seed predators is critical in determining the peak year of sound-seed production.     

Cytologic features of hyalinizing trabecular adenoma of the thyroid

OBJECTIVE: To clarify the cytologic findings of hyalinizing trabecular adenoma (HTA) in order to reduce erroneous diagnoses of papillary carcinoma. STUDY DESIGN: Review of aspiration cytologic smears of 16 HTA cases and comparison with those of 20 papillary carcinoma cases. RESULTS: The smears from HTA were slightly cellular, and 5 of 16 cases were insufficient for evaluation. Vague, curved nuclear palisading, radiating arrangement surrounding hyaline materials and yellow bodies were observed in 9 (81.8%) of 11 cases that had sufficient material. The tumor cells were mainly spindled; elongated, polygonal and stellate cells were also seen. In 9 of 11 cases, tumor cells with cytoplasmic processes were occasionally observed. The cytoplasm was faintly stained and somewhat filamentous. The cell border was indistinct. Neither papillary nor follicular structures were seen. Intranuclear cytoplasmic inclusions were identified in 100% of HTA and 75% of papillary carcinomas. The incidences of nuclear grooves in HTA and papillary carcinoma were 81.8% and 100%, respectively. CONCLUSION: Cytologic findings indicating HTA are vague, curved nuclear palsiading; radiating arrangement surrounding hyaline material; elongated cells; cell processes; ill-defined cell border; faintly stained and filamentous cytoplasm; yellow bodies; and hyaline material in the background. All are useful cytologic characteristics in distinguishing HTA from papillary carcinoma. A lack of papillary architecture and sheetlike arrangement may also suggest HTA rather than papillary carcinoma.     

Free radical scavenging activity of propolis

We investigated the radical scavenging activity of propolis by ESR spectroscopy using spin trapping method. In addition, we examined the influence of a diet of 2% propolis on mice under oxidative stress. At low concentrations, the methanolic extract of propolis exhibited strong scavenging activity in vitro towards both the superoxide anion radical, generated by the hypoxanthine-xanthine oxidase reaction, and the NO radical, generated from the mixture of NOC-7 (NO generator) and carboxy-PTIO (spin trapping agent). An inhibitory effect of propolis on lipid peroxidation in vivo was observed, as determined by measurement of thiobarbituric acid-reactive substances in mouse liver homogenate. The level of vitamin C in the brain of mice under oxidative stress significantly increased compared with control mice under atmosphere, which was not observed in the mice given 2% propolis. The level of alpha-tocopherol in the brain of mice given 2% propolis significantly increased compared with control mice under atmosphere, which was not observed in mice under oxidative stress. SOD activity in the brain and plasma of mice given 2% propolis significantly decreased under atmosphere and oxidative stress compared with control mice. These results suggest that propolis possesses potent antioxidant activity in vitro and in vivo.     

The second meiosis occurs in cytochalasin D-treated eggs of Corbicula leana even though it is not observed in control androgenetic eggs because the maternal chromosomes and centrosomes are extruded at first meiosis

The hermaphroditic freshwater clam Corbicula leana reproduces by androgenesis. In the control (androgenetic development), all maternal chromosomes and maternal centrosomes at the meiotic poles were extruded as the two first polar bodies, and subsequently, second meiosis did not occur. But, in C. leana eggs treated with cytochalasin D (CD) to inhibit polar body extrusion, the second meiosis occurred. At metaphase-I, the spindle showed the typical bipolar structure and two spheroid centrosomes were located at its poles. All the maternal chromosomes were divided at anaphase-I, but they were not extruded as polar bodies due to the effects of CD. After completion of first meiosis, the maternal centrosomes split into four. At the second meiosis, twin or tetrapolar spindles were formed and two groups of maternal chromosomes divided into four sets of chromosomes. After the second meiosis, the spindle disassociated and the four maternal centrosomes disappeared. Four groups of maternal chromosomes transformed into the four female pronuclei. Male and female pronuclei became metaphase chromosomes of the first mitosis. The present study clearly indicates that typical meiosis systems still proceed in androgenetic triploid C. leana. We conclude that the androgenetic form may have arisen from the meiotic form.     

Hypoxia stimulates pancreatic stellate cells to induce fibrosis and angiogenesis in pancreatic cancer

Pancreatic cancer is characterized by excessive desmoplastic reaction and by a hypoxic microenvironment within the solid tumor mass. Chronic pancreatitis is also characterized by fibrosis and hypoxia. Fibroblasts in the area of fibrosis in these pathological settings are now recognized as activated pancreatic stellate cells (PSCs). Recent studies have suggested that a hypoxic environment concomitantly exists not only in pancreatic cancer cells but also in surrounding PSCs. This study aimed to clarify whether hypoxia affected the cell functions in PSCs. Human PSCs were isolated and cultured under normoxia (21% O(2)) or hypoxia (1% O(2)). We examined the effects of hypoxia and conditioned media of hypoxia-treated PSCs on cell functions in PSCs and in human umbilical vein endothelial cells. Hypoxia induced migration, type I collagen expression, and vascular endothelial growth factor (VEGF) production in PSCs. Conditioned media of hypoxia-treated PSCs induced migration of PSCs, which was inhibited by anti-VEGF antibody but not by antibody against hepatocyte growth factor. Conditioned media of hypoxia-treated PSCs induced endothelial cell proliferation, migration, and angiogenesis in vitro and in vivo. PSCs expressed several angiogenesis-regulating molecules including VEGF receptors, angiopoietin-1, and Tie-2. In conclusion, hypoxia induced profibrogenic and proangiogenic responses in PSCs. In addition to their established profibrogenic roles, PSCs might play proangiogenic roles during the development of pancreatic fibrosis, where they are subjected to hypoxia.