Melanoma progression exhibits a significant impact on connexin expression patterns in the epidermal tumor microenvironment

Melanoma depends on, interacts with and reacts to the stroma in which it is embedded, including fibroblasts, extracellular matrix, endothelial cells and immune cells. However, the impact of melanoma on the epidermal tumor microenvironment—the multilayered epithelium of the skin—is poorly understood. Gap junctions are essential for intercellular communication and involved in proliferation, differentiation and homeostasis of keratinocytes. We have shown previously that the gap junction proteins connexin 26 and 30 (Cx26 and Cx30) are induced in the epidermal tumor microenvironment of skin cancers including melanoma. This study compares the extent of Cx26, Cx30 and Cx43 expression in the epidermal microenvironment of melanocytic nevi and melanomas and its association with melanoma thickness, proliferative index of the tumor and its microenvironment, and with 5-year metastasis and survival. We found that induction of Cx26 and Cx30 cell–cell border expression in the epidermal tumor microenvironment correlates to malignancy. Importantly, there was a significant correlation of tumor thickness with the vertical epidermal Cx26 and Cx30 expression pattern and the horizontal Cx26 dissemination. Furthermore, horizontal Cx26 expression correlated with metastasis. Vertical epidermal expression patterns of Cx26 and Cx30 significantly correlated with the proliferative index in the epidermal tumor microenvironment but not with the proliferative index in the tumor. In contrast, Cx43 did not correlate with malignancy, thickness or proliferative index. In summary, here we show for the first time a significant association between the progression of melanoma and alterations in its epithelial tumor microenvironment.     

On subspecific taxa ofHypericum empetrifolium (Hypericaceae) from Crete

The morphology, altitudinal distribution and phytocoenology ofHypericum empetrifolium Willd., var.oliganthum Rech. fil. and var.tortuosum Rech. fil. are reassessed and as a result, the taxa are treated at subspecific rank. Essential characters proved to be growth form, number of flowers, foliage and epidermal surface characters, shape of seeds and testa sculpturing.The different growth forms can be interpreted as adaptations to the local habitats.Hypericum empetrifolium Willd. subsp.empetrifolium is a low subshrub of various vegetation types known as phrygana whereasHypericum empetrifolium Willd. subsp.oliganthum (Rech. f.)Hagemann grows as a cushion-like dwarf shrub in chasmophyte associations rich in relic species.Hypericum empetrifolium Willd. subsp.tortuosum (Rech. f.)Hagemann is confined in the high mountain regions and grows as a true dwarf espalier shrub with low spreading shoots.Dedicated to Hofrat Univ.-Prof. DrK. H. Rechinger on the occasion of his 80th birthday.     

Distribution and functional role of laminin during induction of the embryonic axis in the chick embryo

Laminin is a major glycoprotein of basement membranes and has been shown to promote cell adhesion, and movement of various nonepithelial cells and tumour cells. Using antibodies to laminin in paraffin sections and cultured embryos, we have studied the distribution of laminin and its involvement in the first morphogenetic events, beginning with the first extensive cellular migrations and interactions that result in the induction of the primitive streak (PS) and of the neural plate in the early chick embryo. Laminin immunogold labeling was not detected in the blastoderm at stage X. At stage XIII, laminin immunoreactivity was detected at the ventral surface of the epiblast and in the entire hypoblast. The intense labeling of the hypoblast indicated that these cells are active in laminin synthesis. Extracellular matrix (ECM) started accumulating as the first embryonic spaces were forming, before the morphogenetic movements of gastrulation were initiated. Immunogold labeling revealed a punctate pattern of laminin distribution in the ECM in the blastocoele, and in the space below the neural plate. Laminin, which is a multidomain molecule known to interact with other molecules of the ECM and with the cell surface, could serve as the scaffold for highly specific contact points of migrating cells and for the folding of epithelial sheets during this time in the developing embryo. We incubated blastoderms at stages X and XIII with laminin antibodies (1:30 dilution) for 4 h, then cultured the blastoderms further in plain egg albumin. The laminin antibodies did not interfere with triggering of PS cell movements, but perturbed the normal migration pattern of these cells. A normal PS did not form and, as a consequence, the embryonic axis was not induced.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of salt- and heat-induced alterations of protein synthesis in the cyanobacterium Synechocystis sp. PCC 6803

Protein synthesis of the cyanobacterium Synechocystis spec. PCC 6803 decreases after a 684 mM NaCl salt shock. Qualitative changes were observed during the shock and the subsequent adaptation process using one-dimensional polyacrylamide electrophoresis. Proteins of apparent molecular masses of 13.0, 14.2, 16.6, 20.0, 21.0, 23.0, 33.0, 47.0, 52.0, 65.0 and 72.0 kDa are synthesized at enhanced rates after salt stress. The proteins of 14.2, 21.1 and 52.0 kDa are transiently induced during the first hours of the adaptation phase, while the other proteins are also synthesized at enhanced rates in salt-adapted cells. The proteins of 14.2, 23.0, 33.0 and 65.0 kDa are also induced by heat shock (43°C). Heat shock proteins of about 88.0, 75.0, 58.0, 17.5 and 13.8 kDa, in contrast, are induced by heat shock but not by salt. Two-dimensional polyacrylamide electrophoresis showed that the induced salt and heat shock proteins in some cases consisted of isoforms of different isoelectric points.Abbreviations IP isoelectric point - PAGE polyacrylamide gel electrophoresis - PMSF phenylmethylsulfonyl fluoride     

Differential heat shock gene expression in chick blastula

Summary The component areas of chick blastula show differential expression of heat shock genes. The area opaca (ao), marginal zone (mz) and central area (ca) components of the epiblast display distinct quantitative and minor qualitative differences in the heat-induced and heat-repressible proteins, but are clearly different from the primary hypoblast (endoderm) in their expression of a given stress protein (hsp) as a response to heat shock. The major proteins synthesized in the component areas of epiblast in response to heat shock include hsp 18, 24, 70 and 89 Kd. Two-dimensional electrophoresis shows that each of these proteins consists of multiple charged species. The hypoblast expresses only hsp 70 Kd at non-significant levels and shows marked inhibition in the level of synthesis of heat-shock-repressible proteins. Heat shock during the blastula stage results in an increase in the size of the blastoderm and disrupts normal embryonic development. The heat shock genes provide an important molecular marker, which attests to regional specification in the chick blastula.     

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Repair Kinetics of Radiation-Induced Mitotic Delay

The recovery from radiation-induced mitotic delay in asynchronous sarcoma-180 (S-180) ascites tumor cells has been analyzed in a manner analogous to the repair of sublethal damage. 200-R increments were separated by various fraction intervals (not exceeding the time necessary for mitosis to return to control levels) for total exposures up to 1600 R. The accumulated mitotic delay after the last exposure increment, in percent of an equivalent single exposure, decreased exponentially with overall treatment time in a bimodal fashion. An initial repair process displayed a half time of 2.3 h of overall elapsed time and was followed by a slower process with a half time of 15.1 h. Such a bimodal recovery provides an explanation of why fractionation intervals long with respect to the amitotic period resulting from a single 200 R exposure enhance mitotic delay over that of equivalent single exposures, while shorter fractionation intervals diminish it. It also predicts that mitotic delay vs. dose curves should bend toward the abscissa as the exposure time is increased with large single exposures and large fractionated exposures given over short fraction intervals.     

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