Changes in cytokeratin expression in epidermal keratinocytes during wound healing

In order to investigate the re-epithelialization process during wound healing, the hair on the back of guinea pigs was shaved and then excisional wounds were made through the entire thickness of the skin. Histological changes were observed and changes in the expression of different cytokeratin polypeptides were examined using an immunohistochemical technique. Immunohisto chemical study revealed that the proliferating and migrating keratinocytes expressed the same cytokeratins as the basal cells of normal epidermis. In addition, the entire epidermis of fairly remote areas from the edges of the wound where no thickening was observed showed a temporarily abnormal staining pattern. The suprabasal cells in the regenerating epidermis temporarily expressed cytokeratins not only specific for suprabasal cells but also specific for basal cells. The cytokeratins expressed in normal basal keratinocytes were also present in the thickened granular layers. These data indicate that the expression of cytokeratins in the epidermal keratinocytes (even in fairly remote areas from the wound edges) changes during wound healing, that the origin of the migrating keratinocytes from the remaining epidermis seems to be the basal cells in the epidermis, and that the appearance of keratohyalin granules is not related to changes in cytokeratin expression.     

Influence of Axis Removal on Amino-, Carboxy- and Endopeptidase Activities in Cotyledons of Germinating Vigna mungo Seeds

Endopeptidase (azocaseolytic enzyme) and carboxypeptidase activitiesin cotyledons of germinating Vigna mungo seeds increased until3 days after the onset of imbibition and decreased thereafter.In detached and incubated cotyledons, the endopeptidase activityincreased only a little while the carboxypeptidase activitycontinued increasing even after 3 days of incubation. The activitiesof leucine-aminopeptidase and alanine-aminopeptidase, exceptfor that of one leucine-aminopeptidase isoenzyme relativelyabundantly present in unimbibed dry cotyledons, increased slightlyon the first day and declined during germination. In detachedcotyledons, the activities maintained their initial levels throughoutthe incubation period. When cotyledons were detached from germinatingseedlings on days 2 and 4 then incubated, the endopeptidaseactivity started to decrease just after removal of the axisbut the carboxypeptidase activity increased more markedly thanwhen the axis remained attached. Exogenously supplied GA₃, kinetin,IAA, or their combinations, showed no significant effect onthe developmental patterns of the endopeptidase and carboxypeptidaseactivities in cotyledons. These results are discussed in relationto the role of the axis in controlling peptidase formation incotyledons of germinating V. mungo seeds. (Received November 18, 1983; Accepted February 28, 1984)     

Spontaneous and Ethyl Methanesulfonate-Induced Mutations Controlling Viability in DROSOPHILA MELANOGASTER. III. Heterozygous Effect of Polygenic Mutations

Spontaneous and EMS-induced mutations were accumulated for several generations on the second chromosome of Drosophila melanogaster by keeping this chromosome heterozygous under conditions of minimal natural selection. This article reports studies of heterozygous effects of these mutants.--Both lethal and mildly deleterious mutants have a deleterious heterozygous effect. There was no discernible difference between heterozygotes in which all the mutants were on one chromosome and those where the mutants were distributed over both homologs; thus the coupling-repulsion effect of MUKAI and YAMAZAKI (1964, 1968) is not confirmed. The spontaneous polygenic mutants have a dominance of 0.4 to 0.5, and the same value is found at very low EMS doses. However, the value at higher EMS doses is only about half as high. Since the low doses have a large fraction of spontaneous mutants, the dominance of EMS mutants is less, in the range 0.1 to 0.3, but still larger than for lethals.     

Spin coupling between electron carriers in the dehydrogenase segments of the respiratory chain.

The $\text{in vitro}$ RNA synthesis and poly(A) synthesis catalyzed by cauliflower RNA polymerase are stimulated by an addition of polyethylenimine (PEI) at a low concentration to the reaction medium. Evidence is presented that PEI exerts its stimulative effect on a reaction coexisting of enzyme, template, and substrate, and not on the template or enzyme alone.     

Transmembrane phospholipid motions induced by F glycoprotein in hemagglutinating virus of Japan.

Transfer of phospholipid from the envelope of hemagglutinating virus of Japan (HVJ) to erythrocyte (RBC) membrane and the virus-induced transfer of phospholipid between RBC membranes were studied using spin-labeled phosphatidylcholine (PC). The transfer of PC from membranes labeled densely with PC to unlabeled membranes was followed by the peak height increase in the electron spin resonance spectrum. The two kinds of transfer reactions took place very rapidly as reported previously. To obtain further details, the transfer reactions were studied with HVJ, HVJ inactivated by trypsin, HVJ harvested early, HVJ grown in fibroblast cells, the fibroblast HVJ activated by trypsin, influenza virus, and glutaraldehyde-treated RBCs. The results demonstrated that the viral F glycoprotein played a crucial role in the transmembrane phospholipid movements as well as in the fusion and hemolysis of RBCs. The transfer from HVJ to RBC's occurred partially through an exchange mechanism not accompanying the envelope fusion. This was shown by a decrease in the exchange broadening of the electron spin resonance spectrum of released spin-labeled HVJ (HVJ) and also by an increase in the ratio of PC to viral proteins incorporated into RBC membranes. HVJ modified RBC membrane so as to be able to exchange its phospholipids with those of inactive membranes such as fibroblast HVJ, influenza virus, glutaraldehyde-treated RBC'S, and phosphatidylcholine vesicles. HVJ affected the fluidity of RBC membranes markedly, the environments around PC being much fluidized. The virus-induced fusion was discussed based on close apposition of the membranes by HANA proteins and on the destabilization and fluidization of RBC membranes by F glycoproteins.     

Characterization of iron-sulfur clusters in rat liver submitochondrial particles by electron paramagnetic resonance spectroscopy. Alterations produced by chronic ethanol consumption

Iron-sulfur clusters present in rat liver submitochondrial particles were characterized by ESR at temperatures between 30 and 5.5 K combined with potentiometric titrations. The spectral and thermodynamic characteristics of the iron-sulfur clusters were generally similar to those previously reported for pigeon or bovine heart submitochondrial particles. Clusters N-1a, N-1b, N-2, N-3 and N-4 of NADH dehydrogenase had midpoint oxidation-reduction potentials at pH 7.5 of ?425, ?265, ?85, ?240 and ?260 mV, respectively. Clusters S-1 and S-3 of succinate dehydrogenase had midpoint potentials of 0 and +65 mV, respectively. The iron-sulfur cluster of electron-transferring flavoprotein-ubiquinone oxidoreductase exhibited the g_z signal at g = 2.08 and had a midpoint potential of +30 mV. This signal was relatively prominent in rat liver compared to pigeon or bovine heart.Submitochondrial particles from rats chronically treated with ethanol (36% of total calories, 40 days) showed decreases of 20–30% in amplitudes of signals due to clusters N-2, N-3 and N-4 compared to those from pair-fed control rats. Signals from clusters N-1b, S-1, S-3 and electron-transferring flavoprotein-ubiquinone oxidoreductase were unaffected. Microwave power-saturation behavior was similar for both submitochondrial particle preparations, suggesting that the lower signal amplitudes reflected a lower content of these particular clusters. NADH dehydrogenase activity was significantly decreased (46%), whilst succinate dehydrogenase activity was elevated (25%), following chronic ethanol consumption. The results indicate that chronic ethanol treatment leads to an alteration of the structure and function of the NADH dehydrogenase segment of the electron transfer chain. This alteration is one of the factors contributing to the lower respiration rates observed following chronic ethanol administration.     

Reduction by a model of NAD(P)H: XI. Stereochemistry of a lactate dehydrogenase-model reaction

Stereochemistry of the biomimetic reduction of α-keto esters with NAD(P)H-model compounds has been investigated. The model compound with the R-configuration reduces the α-keto esters to the (R)-α-hydroxy esters, whereas (S)-α-hydroxy esters are afforded by the reduction with the S-configurational model compounds. It has been concluded that pro-R and -S hydrogens of the model compounds with R- and S-configuration, respectively, contribute predominantly to the reduction.