Brachythecium complexum J.D.Orgaz,sp. nov., a new species from Japan

Abstract

Two types of fires were distinguished, rapid fires and bonfires, the amount of ash deposited and the intensity of heating both being greater during a bonfire. Rapid-fire sites are recolonized largely by the pre-burn species, but on bonfire sites, after an initial delay period, in which both angiosperm and bryophyte growth is inhibited, a characteristic bonfire community is formed in which Funaria hygrometrica is the most conspicuous species. Field experiments and soil analyses confirmed that edaphic conditions were of primary importance in determining the establishment of the bonfire community and showed that a major difference between the two sorts of fire lay in their effect on the surface soil.

After a bonfire, high concentrations of soluble organic matter and inorganic nutrients were found. With the exception of the calcium concentrations, these decreased with time, the levels of potassium, magnesium and phosphorus approaching or even reaching those of the unburnt soil after 18 months. It seems very likely that after an initial increase in the levels of both ammonium- and nitrate-nitrogen, the rate of nitrification would be stimulated and remain high for a considerable length of time. Rapid fires, as expected, appeared to have relatively little effect on the surface soil, levels of calcium and phosphorus in particular were never as high as in bonfire soils and it is most unlikely that there was any stimulation of nitrification.     

Xylitol Production by a Corynebacterium Species

The washed cells of a gluconate-utilizing Corynebacterium strain grown in a gluconate- xylose medium produced xylitol from D-xylose in the presence of gluconate. The amount of xylitol was progressively increased with increasing gluconate concentration.

An extract of cells grown in the gluconate-xylose medium showed NADPH-dependent D-xylose reductase activity and NADP-dependent 6-phosphogluconate dehydrogenase activity.

These enzymes in the cell-free extract were purified by Sephadex G–100 gel filtration.

The reduction of D-xylose to xylitol was demonstrated by the coupling the D-xylose reductase activity to the 6-phosphogluconate dehydrogenase activity with NADP as a cofactor using the cell-free extract and the fractionated enzymes.     

Biological evaluation of novel benzisoxazole derivatives as PPARδ agonists

We discovered novel peroxisome proliferator-activated receptor δ agonists with a characteristic benzisoxazole ring. Compound 5 exhibited potent human PPARδ transactivation activity. Furthermore, it stimulated the differentiation of oligodendrocyte precursor cells in vitro. This indicates that this potential drug may be effective for the treatment of demyelinating disorders such as multiple sclerosis.     

A monoclonal antibody against insect CALNUC recognizes the prooncoprotein EWS specifically in mammalian cells. Immunohistochemical and biochemical studies of the antigen in rat tissues

A monoclonal antibody against insect CALNUC was shown to recognize an 85-kDa nuclear protein specifically in mammalian cells. Amino acid sequencing of the protein purified from rat liver revealed it to be EWS, a prooncoprotein for Ewing sarcomas and related tumors. Using the antibody, distribution of EWS was studied in rat tissues fixed with 4% paraformaldehyde by immunohistochemical methods. On thaw-fixed cryosections or those of perfusion-fixed tissues, almost all cell nuclei showed the specific staining. In immersion-fixed tissues, the staining unexpectedly disappeared in particular tissues (kidney cortex, liver, etc.), although it was recovered by autoclaving the cryosections. Western blotting also demonstrated the ubiquitous expression of EWS in the tissues. In extracts from the liver, the 85-kDa band rapidly disappeared in a Ca(2+)-dependent manner, but never in the testis. The antigen was very labile in kidney homogenates even without Ca2+. Biochemical studies with digoxigenin-labeled EWS showed that the Ca(2+)-dependent disappearance was associated with upward mobility shifts of EWS. These suggested that EWS was ubiquitously expressed in rat tissues, and that the antigen was masked in particular tissues during the immersion fixation.     

Labeling of v-Src and BCR-ABL tyrosine kinases with [C]herbimycin A and its use in the elucidation of the kinase inactivation mechanism

The ansamycin antibiotic, herbimycin A, selectively inactivates cytoplasmic tyrosine kinases, most likely by binding irreversibly to the reactive SH group(s) of kinases. To further investigate the mechanism of herbimycin A action, we attempted to label tyrosine kinases with [¹⁴C]herbimycin A. p60^v-src and p2 10^BCR-ABL in immune complexes were labeled with [¹⁴C]herbimycin A, demonstrating that the antibiotic binds directly to tyrosine kinases. Digestion of [¹⁴C]herbimycin A-labeled p60^v-src with Staphylococcus taureus V8 protease revealed that the herbimycin A binding site is within the C-terminal 26-kDa fragment of p60^v-src, which contains the tyrosine kinase domain. Herbimycin A treatment inhibited labeling of p60^v-src by [¹⁴]C]fluorosulfonylbenzoyl adenosine, an affinity labeling reagent of nucleotide binding sites, indicating that herbimycin A-modified p60^v-src cannot interact with ATP. The results suggest that herbimycin A inactivates tyrosine kinases by binding directly to the kinase domain, thereby inhibiting access to ATP.     

Arm-specific telomere dynamics of each individual chromosome in induced pluripotent stem cells revealed by quantitative fluorescence in situ hybridization

We have reported that telomere fluorescence units (TFUs) of established induced pluripotent stem cells (iPSCs) derived from human amnion (hAM933) and fetal lung fibroblasts (MRC-5) were significantly longer than those of the parental cells, and that the telomere extension rates varied quite significantly among clones without chromosomal instability, although the telomeres of other iPSCs derived from MRC-5 became shorter as the number of passages increased along with chromosomal abnormalities from an early stage. In the present study we attempted to clarify telomere dynamics in each individual chromosomal arm of parental cells and their derived clonal human iPSCs at different numbers of passages using quantitative fluorescence in situ hybridization (Q-FISH). Although no speci?c arm of any particular chromosome appeared to be consistently shorter or longer than most of the other chromosomes in any of the cell strains, telomere elongation in each chromosome of an iPSC appeared to be random and stochastic. However, in terms of the whole genome of any specific cell, the telomeres showed overall elongation associated with iPSC generation. We have thus demonstrated the specific telomere dynamics of each individual chromosomal arm in iPSCs derived from parental cells, and in the parental cells themselves, using Q-FISH.     

Involvement of protein phsophatase-1 in cytoskeletal organization of cultured endothelial cells

The phosphorylation and dephosphorylation of cytoskeletal proteins regulate the shape of eukaryotic cells. To elucidate the role of serine/threonine protein phosphatases (PP) in this process, we studied the effect of calyculin A (CLA), a potent and specific inhibitor of protein phosphatases 1 (PP-1) and 2A (PP-2A) on the cytoskeletal structure of cultured human umbilical vien endothelial cells (HUVECs). The addition of CLA (5 min) caused marked alterations in cell morphology, such as cell constriction and bleb formation. Microtubules and F-actin were reorganized, becoming markedly condensed around the nucleus. Although the fluorescence intensity of phosphoamino acids was not significantly different to immunocytochemistry between cells with and without CLA, polypeptides of 135, 140, 158, and 175 kDa were specifically phosphorylated on serine and/or threonine residues. There was no significant effect on tyrosine residues. The effects of CLA on cytoskeletal changes and protein phosphorylation were almost completely inhibited by the non-selective kinase inhibitor, K-252a. The effect of CLA on cell morphology was at least 100 times more potent than that of okadaic acid, consistent with the inhibitory potency against PP-1. The catalytic subunit of PP-1 was also identified in HUVECs by Western blotting with its monoclonal antibody. These results suggest that PP-1 is closely involved in sustaining the normal structure of the cytoskeleton. © 1995 Wiley-Liss, Inc.