New siphulin derivatives from the lichen Siphula ceratites

From the lichen, Siphula ceratites, two new metabolities, protosiphulin and oxysiphulin, were isolated besides the known compound, siphulin. The structures of the two new chromenones were proved by ¹H NMR and ¹³C NMR spectral analysis in comparison with those of siphulin.     

Effects of auxin on the structure of hemicelluloses of Avene coleoptiles

Avena coleoptile hemicelluloses were fractionated into water-solublehemicelluloses I and IIB and water-insoluble hemicellulose IIA.These hemicelluloses were then subjected to glycosidic linkageanalysis by methylation technique, which revealed that hemicelluloseI was predominantly composed of arabinoxylans and ß-(l4)glucans and hemicellulose IIB was composed of arabinoxylans,ß-(l4) : (l3)-mixed linked glucans, ß-(l4)-glucansand xyloglucans. Hemicellulose IIA was mainly composed of xyloglucansand probably ß-(l4)-glucans. Methylation analysisof hemicelluloses extracted from Avena coleoptile segments treatedwith auxin in the presence of mannitol (0.15 M) indicated thatauxin apparently had no effect on the structure of arabinoxylanand caused a specific decrease in the amount of ß-(l4): (l3)-mixed linked glucan. (Received November 19, 1979; )     

Component analysis and growth process of nasopharyngeal calculus as revealed by Fourier transform infrared (FT-IR) spectroscopy.

A quite rare case of nasopharyngeal calculus in a woman in her twenties associated with the nasal discharge of pseudomonas infection was reported. As the substance was irregularly large in size, we extracted it partially by piecemeal resection using forceps and also by cracking technique using the holmium yttrium-aluminum-garnet (YAG) laser, under saline irrigation and stereotactic microscopic navigator (SMN) system under endoscopic observation. The substance was firmly fixed to the pharyngeal tonsil bed. The final extract was a small piece of singly folded bandage, which is probably the focal background for calculus formation. In a cross section of calculus specimen removed during surgery, Fourier transform infrared (FT-IR) analysis revealed that a) signal ratio of methylene group (organic substance) to amide I (protein) was 21.6% at the nasal cavity side, gradually decreased toward nasal mucous membrane showing approximate 50%, b) signal ratio of amide I to P04(3-) (inorganic substance) ranged between 17.7% and 26.7% at the different sites and inside the calculus, the protein content was approximate 1/5 of the inorganic substance, and c) signal ratio of the methylene group to amide I at the nasal cavity site showed that their contents were almost equal. The quantity of the organic substance was estimated at approximate 1/2 quantity of the protein at both the central part and the part contacted with the mucous membrane. From these results, it seems that throughout the course of calculus growth, both inorganic substance and protein remain almost constant inside the calculus, while organic substance is released from the internal part of the calculus being probably formed at an early stage.     

Induction of G1 cell cycle arrest in human umbilical vein endothelial cells by flavone's inhibition of the extracellular signal regulated kinase cascade.

Dietary flavonoids have demonstrated anti-carcinogenic activity in several animal models, but their mechanisms of action have not yet been clearly established. Here, we show that flavone, a parent compound of flavonoids, inhibits the proliferation, migration, and capillary tube formation of human umbilical vein endothelial cells (HUVECs). Flow cytometric analysis showed that flavone arrests the cell cycle progression at G(1) phase in HUVECs. We observed the down-regulation of the hyperphosphorylated form of retinoblastoma gene product and cyclin-dependent kinases 2 and 4 in flavone-treated cells, but it had no affect on the expression of p53 and cyclin-dependent kinase inhibitors p21(CIP/Waf1) and p27(Kip). Flavone almost completely inhibited the activation of extracellular signal regulated kinase 1. The present results suggest that the flavone moiety of flavonoids is required for anti-proliferative activity of flavonoids and that anti-carcinogenic action of flavonoids in vivo was mediated, at least in part, by inhibiting angiogenesis.     

Synthesis and biological activities of methyl oligobiosaminide and some deoxy isomers thereof

Methyl oligobiosaminide (1) the core structure of oligostatin C, and five analogues, the 6-hydroxy-(2), 2-deoxy- (3), 2-deoxy-6-hydroxy- (4), 3-deoxy- (5), and 3-deoxy-6-hydroxy derivatives (6), were synthesized by coupling the protected pseudo-sugar epoxide 46 with suitable methyl 4-amino-4-deoxy-alpha-D-hexopyranoside derivatives. Compounds 3 and 6 showed notable inhibitory activity against alpha-D-glucosidase and alpha-D-mannosidase, respectively, whereas compound 1 had almost no activity.     

Stimulation of the insulin-sensitive cAMP phosphodiesterase by an ATP-dependent soluble factor from insulin-treated rat adipocytes

The insulin-sensitive cAMP phosphodiesterase (PDE) in the microsomal fraction (Fraction P-2) from basal (-insulin) rat adipocytes was stimulated upon incubation with 2 mM ATP plus the soluble fraction from insulin-treated adipocytes (Fraction S-2+). Fraction S-2+ was prepared in the presence of p-nitrophenylphosphate, sodium vanadate, and EGTA. The ATP-dependent stimulation of PDE was routinely 60-70%. The unknown factor in Fraction S-2 was water-soluble, heat-labile, excluded by Sephadex G-50, mostly retained by Sephadex G-100, and not inhibited with 1 microgram/ml heparin, 3 mM CaCl2, or 30 mM NaF. The soluble factor may be a mediator of insulin action on PDE, possibly a protein kinase.     

In vitro responsiveness of aldosterone-producing adenoma to angiotensin II, K and ACTH

In vitro responsiveness to various stimulators of aldosterone secretion was studied in a perifusion system using slices obtained from three aldosterone-producing adenomas (APAs), three adjacent nontumorous glands and three normal adrenal glands. All three APA tissues responded to angiotensin II, K and ACTH in vitro. Angiotensin II (10 nM), K (12 mM) and ACTH (10 nM) caused more than a 2-fold increase in aldosterone secretion. The sensitivity of APA tissues to angiotensin II was identical to that in normal adrenal cortex. In slices obtained from APA, angiotensin II induced rapid increases in [3H]inositol and [45Ca] efflux, both of which preceded the aldosterone response. These results suggest that APA cells have an almost normal transducing system to stimulators of aldosterone secretion.     

Chloroplast DNA of black pine retains a residual inverted repeat lacking rRNA genes: nucleotide sequences of trnQ, trnK, psbA, trnI and trnH and the absence of rps16

Summary A physical map of black pine (Pinus thunbergii) chloroplast DNA (120 kb) was constructed and two separate portions of its nucleotide sequence were determined. One portion contains trnQ-UUG, ORF510, ORF83, trnK-UUU (ORF515 in the trnK intron), ORF22, psbA, trnI-CAU (on the opposing strand) and trnH-GUG, in that order. Sequence analysis of another portion revealed the presence of a 495 by inverted repeat containing trnI-CAU and the 3 end of psbA but lacking rRNA genes. The position of trnI-CAU is unique because most chloroplast DNAs have no gene between psbA and trnH (trnI-CAU is usually located further downstream). Black pine chloroplast DNA lacks rps16, which has been found between trnQ and trnK in angiosperm chloroplast DNAs, but possesses ORF510 instead. This ORF is highly homologous to ORF513 found in the corresponding region of liverwort chloroplast DNA and ORF563 located downstream from trnT in Chlamydomonas moewusii chloroplast DNA. A possible pathway for the evolution of black pine chloroplast DNA is discussed.     

The alpha-helix to beta-sheet transition in poly(L-lysine): effects of anesthetics and high pressure.

Poly(L-lysine) exists in a random-coil formation at a low pH, alpha-helix at a pH above 10.6, and transforms into beta-sheet when the alpha-helix polylysine is heated. Each conformation is clearly distinguishable in the amide-I band of the infrared spectrum. The thermotropic alpha-to-beta transition was studied by using differential scanning calorimetry. At pH 10.6, the transition temperature was 43.5 degrees C and the transition enthalpy was 170 cal/mol residue. At pH 11.85, the measurements were 36.7 degrees C and 910 cal/mol residue, respectively. Volatile anesthetics (chloroform, halothane, isoflurane and enflurane) partially transformed alpha-helix polylysine into beta-sheet. The transformation was reversed by the application of hydrostatic pressure in the range of 100-350 atm. Apparently, the alpha-to-beta transition was induced by anesthetics through partial dehydration of the peptide side-chains (beta-sheet surface is less hydrated than alpha-helix). High pressure reversed this process by re-hydrating the peptide. Because the membrane spanning domains of channel and receptor proteins are predominantly in the alpha-helix conformation, anesthetics may suppress the activity of excitable cells by transforming them into a less than optimal structure for electrogenic ion transport and neurotransmission. Proteins and lipid membranes maintain their structural integrity by interaction with water. That which attenuates the interaction will destabilize the structure. These data suggest that anesthetics alter macromolecular conformations essentially by a solvent effect, thereby destroying the solvation water shell surrounding macromolecules.     

Impairment of cold-induced increase in thyroxine 5'-deiodinase activity in mouse brown adipose tissue by the intracerebroventricular administration of bombesin.

Effects of bombesin on brown adipose tissue (BAT) thyroxine (T4) 5'-deiodinase (5'D) activity and rectal temperature were examined in male mice. Immediately following an intracerebroventricular (ICV) or intravenous (IV) injection of bombesin (0.1-100 ng/animal) or vehicle (20 mM bacitracin dissolved in 0.9% saline), the mice were placed in a room at 4 degrees C or 22 degrees C for 30, 60, 120 or 240 min. The ICV injection of bombesin dose-dependently lessened cold-induced increase in BAT 5'D activity and increased hypothermia determined at 120 min of cold exposure, whereas the IV injection of bombesin was without effect. Bombesin (ICV)-induced hypothermia preceded the inhibition of BAT 5'D activity by at least 30 min at 4 degrees C. BAT 5'D activity was not affected by ICV injection of bombesin in mice kept at 22 degrees C, although the rectal temperature was significantly decreased. Bombesin thus appears to prevent cold-induced increase in T4 5'D activity in mouse BAT by its central effect. Bombesin-induced excessive hypothermia itself and/or the decrease in sympathetic tone of BAT by bombesin might decrease cold-induced increase in BAT 5'D activity.