Polymer-supported biopolymer synthesis: 3. Preparation of fully and partially protected βh-endorphin segments with a new phenolic poly [N-(2-methoxyethyl)-acrylamide]-based support

A new phenolic peptide resin, which is a bead-form derivative of crosslinked poly[N-(2-methoxyethyl)acrylamide], has been prepared by a suspension polymerization technique. The resin, which is highly expanded in all common peptide solvents, has been used for the solid (gel) phase synthesis of protected acylpeptide hydrazides. Fully protected acylpeptide hydrazide segments corresponding to β_h-endorphin (15–17), β_h-endorphin (6–14) and β_h-endorphin (6–17) have been prepared. Conversion, by selective catalytic transfer hydrogenation, of the fully protected acylpeptide hydrazide segment corresponding to β-_h-endorphin (15–17) to the partially protected form has been explored.     

Increased Drought Tolerance through the Suppression of ESKMO1 Gene and Overexpression of CBF-Related Genes in Arabidopsis

Improved drought tolerance is always a highly desired trait for agricultural plants. Significantly increased drought tolerance in Arabidopsis thaliana (Columbia-0) has been achieved in our work through the suppression of ESKMO1 (ESK1) gene expression with small-interfering RNA (siRNA) and overexpression of CBF genes with constitutive gene expression. ESK1 has been identified as a gene linked to normal development of the plant vascular system, which is assumed directly related to plant drought response. By using siRNA that specifically targets ESK1, the gene expression has been reduced and drought tolerance of the plant has been enhanced dramatically in the work. However, the plant response to external abscisic acid application has not been changed. ICE1, CBF1, and CBF3 are genes involved in a well-characterized plant stress response pathway, overexpression of them in the plant has demonstrated capable to increase drought tolerance. By overexpression of these genes combining together with suppression of ESK1 gene, the significant increase of plant drought tolerance has been achieved in comparison to single gene manipulation, although the effect is not in an additive way. Accompanying the increase of drought tolerance via suppression of ESK1 gene expression, the negative effect has been observed in seeds yield of transgenic plants in normal watering conditions comparing with wide type plant.     

Structure of orthenthose

A new tetrasaccharide, orthenthose, has been isolated from the dried twigs of Orthenthera viminea (Family: Asclepiadaceae). By spectral and chemical procedures, this new tetrasaccharide has been shown to be O-α-l-oleandropyranosyl-(1→4)-O-α-l-oleandropyranosyl-(1→4)-O-α-l-oleandropyranosyl-(1→4)-β-l-oleandropyrano se.     

A new intracellular phytase of enterobacteria: Isolation and characterization

A phytase (myo-inositol-1,2,3,4,5,6-hexakisphosphate phosphohydrolase) has been isolated for the first time from a cell lysate of Pantoea vagans 3.2 enterobacteria and studied. The enzyme has been assigned to the class of histidine acid phosphatases (EC 3.1.3.26). It has been purified to homogeneity, and its primary structure has been determined. The molecular weight of the protein is 46 kDa, and K _m is 0.28 mM. Some physicochemical properties of the enzyme have been examined.     

9-hydroxyrhynchophylline-type oxindole alkaloids

Speciofoline has been assigned the epiallo B configuration on the basis of isomerization studies, NMR and CD spectra, and three new speciofoline isomers, mitrafoline (allo A), isomitrafoline (allo B) and isospeciofoline (epiallo A) have been isolated from Mitragyna speciosa Korth. Two new C-20 vinyl alkaloids, rotundifoleine and isorotundifoleine, have been separated as minor products from crystalline samples of rotundifoline and isorotundifoline respectively, previously isolated from M. parvifolia (Roxb.) Korth. A transient product observed during the isomerization of isorotundifoline has been identified as the pseudo B isomer, 3-epi-isorotundifoline.     

Spectroscopic, magnetic, and electrochemical studies of a dimeric N-substituted-sulfanilamide copper(II) complex. X-ray and molecular structure of the Cu2(N-(pyridin-2-yl)biphenyl-4-sulfonamidate)4 complex

A dinuclear copper(II) complex with a N-substituted sulfonamide as ligand has been investigated. The new N-(pyridin-2-yl)biphenyl-4-sulfonamide ligand has been prepared and structurally characterized. The copper(II) complex has been synthesized and its crystal structure, magnetic properties and EPR spectra were studied in detail. The metal centers are bridged by four nonlinear triatomic NCN groups. The coordination geometry of the copper(II) ions in the dinuclear entity is distorted square planar with two N-pyridyl and two N-sulfonamido atoms. Magnetic susceptibility data show a moderate antiferromagnetic coupling, with −2 J = 284 cm⁻¹. The EPR spectrum of the polycrystalline sample of the title compound has been measured at the X-band frequency at different temperatures.     

Chromosomal variation and evolution in Lycoris (Amaryllidaceae) I. Intraspecific variation in the karyotype of Lycoris chinensis Traub

In 188 bulbs from five populations of Lycoris chinensis from Anhui province, China, several chromosomal variations have been discovered. Although their frequencies are low, some rearranged chromosomes which are aberrant have been found. The aberrants are: (1) small metacentrics (m′); (2) submetacentrics (sm); (3) subtelocentrics (st); (4) acrocentrics (t); and (5) satellite chromosomes (SAT). All can be easily suspected as being derived from telocentric chromosomes (T type chromosomes). Some individuals having one or more B chromosomes have been found, and intrapopulational variation of B chromosomes in number has also been observed. Because of having B chromosome, L. chinensis has some different chromosome complement numbers: 2n?=?16, 2n?=?16?+?1B, 2n?=?16?+?2B, 2n?=?16?+?3B, and 2n?=?16?+?5B. In addition, a new triploid karyotype composed of 3n?=?24?=?9m?+?11t(2SAT)?+?4T chromosomes has been found. Vegetative propagation is an efficient means of perpetuating the aberrant chromosomes and the triploids.     

Centric diatom algae of volcanic Verkhneavachinsk lakes (Kamchatka)

Eleven representatives of diatom algae of the class Centrophyceae from the genera Aulacoseira (1), Conticribra (1), Cyclotella (5), Discostella (1), Stephanodiscus (2), and Thallasiosira (1) have been found in the phytoplankton of 5 volcanic lakes (Bakening volcano, Kamchatka). Stephanodiscus popovskayae, a species new for science, has been discovered in all the lakes, and a species new for the flora of Russia, Cyclotella gordonensis, has been found only in three lakes. The closest similarity in the composition of centric diatoms has been revealed between the lakes of a single water system: Lake Medvezh’e and Lake Verkhneavachinskoe.     

Annonelliptine,an alkaloid from Annona elliptica

Annonelliptine has been isolated from Annona elliptica and its structure has been identified as (R)-7-hydroxy-1-(4′-hydroxybenzyl)-5,6-dimethoxy-N-methyl-1,2,3,4-tetrahydroisoquinoline.     

Glucosinolates in seeds of Neslia paniculata

The glucosinolate fraction in seeds of Neslia paniculata (L.) Desv., subsp. thracica (Velen.) Bornmüller, (Cruciferae), has been isolated and subjected to enzymic hydrolysis. The isothiocyanates thus produced have been separated and identified as cheirolin (II), (R)-9-methylsulfinylnonyl (III), (R)-10-methylsulfinyldecyl (IV), and (R)-11-methylsulfinylundecyl isothiocyanate (V), the last of which has not been previously encountered as a natural compound.     

Distribution of frit flies (Chloropidae: Meromyza Mg.) in Vologda oblast and East Poland

Species diversity and abundance of frit flies from the genus Meromyza have been assessed in coastal biotopes, grasslands, and agro-ecosystems of Vologda oblast (Russia) and Warsaw province (Poland). The Jaccard quotient of similarity (IG) of frit fly abundance has shown a uniformity between coastal banks and grasslands along these banks, as well as between cultivated cereals (except for oats) and field boundaries, cultivated fields, and some reach-in-herbs grasslands, including hayfields. Considerable heterogeneity of species composition of the flies has been revealed in similar biotopes. The biotopes studied have been found to be dominated by one species of frit flies. It has been discovered that cereal rotation in agro-ecosystem results in change in the dominant species of frit fly. The cereal height has been found to influence the abundance and diversity of frit flies. No regularities have been observed in the correlation between the abundances of frit flies in different biotopes. It has been pointed out that M. nigriseta Fed. and M. variegata Mg. can feed on cultivated cereals.     

Structures of verbascoside and orobanchoside,caffeic acid sugar esters from Orobanche rapum-genistae

The complete structural elucidation of the two caffeic acid sugar esters verbascoside and orobanchoside, has been realized by ¹H and ¹³C NMR studies. It has been demonstrated that verbascoside is β-(3′,4′-dihydroxyphenyl)ethyl-O-α-L-rhamnopyranosyl(1→3)-β-D-(4-O-caffeoyl)-glucopyranoside, and orobanchoside is β-hydroxy-β-(3′,4′-dihydroxyphenyl)-ethyl-O-α-L-rhamnopyranosyl(1→2)-β-D-(4-O-caffeoyl)-glucopyranoside.     

Complete nucleotide sequence of the glutamate dehydrogenase gene from Escherichia coli K-12

A 2.3-kb PstI-ClaI chromosomal DNA segment, carrying the complete coding region of the glutamate dehydrogenase (GDH) structural gene from Escherichia coli K-12, has been sequenced. The complete amino acid sequence (447 residues) of the GDH monomer has been deduced, and comparisons are made with reported amino acid sequences of GDH from other organisms.     

Predation on endemic Hawaiian land snails by the invasive snail Oxychilus alliarius

The native land snails of the Hawaiian Islands have suffered numerous extinctions and continue to decline rapidly. A leading cause of these extinctions has been the impact of non-native predators. Oxychilus alliarius is a European predatory snail that has been in Hawaii since at least 1937 and has become one of the most abundant invasive snails in the islands. It is a facultative carnivore and will also consume non-animal food. However, this species has been mostly ignored as a threat and the majority of conservation attention has been focused on Euglandina rosea, the Rosy Wolf Snail. Here we report predation by O. alliarius on two rare and endemic Hawaiian snail species: Kaala subrutila (Helicarionidae) and Pleuropoma cf. sandwichiensis (Helicinidae). The wide distribution of O. alliarius in Hawaii, its high abundance, and now compelling evidence that it preys on native (and probably endangered) snails, indicate that it could be a much greater threat than previously thought.     

(—)-Massoniresinol,a lignan from Pinus massoniana

A new lignan, named (—)-massoniresinol, has been isolated from Pinus massoniana needles. Its structure has been proved to be (2R,3S,4R)-3,4-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-4-(4-hydroxy-3-methoxybenzyl)-3-tetrahydrofuranmethanol by ¹H NMR, ¹³C NMR, mass and CD spectroscopy.     

Chthamalus stellatus (Poli) und C. depressus (Poli) in der adria

A study has been made of the ecology of Chthamalus stellatus (Poli) and C. depressus (Poli) in the region of Rovinj (Yugoslavia). The distribution has been examined at several localities of different habitat conditions particularly with respect to wave action.     

Torvonin-A,a spirostane saponin from Solanum torvum leaves

A new steroidal saponin, torvonin-A, has been isolated from S. torvum leaves and its structure has been established as neochlorogenin-3-O-β-L-rhamnopyranosyl (1→2)β-L-rhamnopyranoside.     

Taste attractiveness of different hydrobionts for roach Rutilus rutilus, bitterling Rhodeus sericeus amarus, and rainbow trout Oncorhynchus mykiss

Comparative study of the taste attractiveness of different aquatic invertebrates (daphnids Daphnia longispina and D. pulex, larvae of Chironomidae, whirligig Gyrinus marinus, water skaters Gerris spp.) and plants (duckweed Lemna minor, filamentous alga Cladophora sp.) for roach Rutilus rutilus, bitterling Rhodeus sericeus amarus, and rainbow trout Oncorhynchus mykiss has been performed. Roach’s taste preferences for agar-agar pellets, containing the aqueous extracts of the organisms under study, varies from maximum (daphnids, filamentous alga, larvae of chironomids) to minimum (duckweed) or it can be absent (whirligig). Different taste preferences to pellets containing the extracts of aquatic organisms has been also found in bitterling (daphnids, larvae of chironomids, water skaters) but not in rainbow trout (daphnids, water skaters). It has been suggested that whirligigs and water skaters do not contain any deterrent substances ensuring chemical defense from predators. It has been demonstrated that intraoral gustatory reception of food items follows two alternative behavioral stereotypes that are different from each other in the time during which food items are retained in the oral cavity and the number of manipulations (subsequent grasps of a food item) during the perception process. We discuss the importance of gustatory reception as the major sensory mechanism that ensures feeding selectivity of fish and decreases interspecific competition over food.     

Magnetic susceptibility equation for dinuclear high-spin cobalt(II) complexes considering the exchange interaction between two axially distorted octahedral cobalt(II) ions

A new magnetic susceptibility equation has been obtained for dinuclear high-spin cobalt(II) complexes considering the exchange interaction between two axially distorted octahedral cobalt(II) ions. A computational program has been developed, and the temperature dependencies of the magnetic susceptibility have been demonstrated. A characteristic χ_A versus T curve due to the zero-field splitting was shown when the distortion parameter v was positive.     

Synthesis and SAR of hydroxyethylamine based phenylcarboxyamides as inhibitors of BACE

A series of N-((2S,3R)-1-(3,5-difluorophenyl)-3-hydroxy-4-(3-methoxybenzylamino)-butan-2-yl)benzamides has been synthesized as BACE inhibitors. A variety of P2 and P3 substituents has been explored, and these efforts have culminated in the identification of several 1,3,5-trisubstituted phenylcarboxyamides with potent BACE inhibitory activity.