Changes in the behavior of the female short-tailed cricket,Anurogryllus muticus (De Geer) (Orthoptera: Gryllidae) following mating

InAnurogryllus muticus females, mating stimulates burrow construction, burrow provisioning, feeding, egg production, and egg-laying. Since mating often occurs before the ovaries are fully developed, the time span between mating and oviposition is used for increased food intake and the accumulation of nutrient reserves in the fatbody. Oviposition triggers maternal care of eggs and emerging hatchlings, and blocks egg consumption. Hatchling behavior is investigated. When hatchlings eat eggs, they prefer newly laid over older, embryonic eggs.     

Generation of Probucol Radicals and Their Reduction by Ascorbate and Dihydrolipoic Acid in Human Low Density Lipoproteins

Probucol, 4.4'-[(1-methylethylidene)bis(thio)]bis-[2,6-bis(1.1-dimethyl)phenol], is a lipid regulating drug whose therapeutic potential depends on its antioxidant properties. Probucol and x-tocopherol were quantitatively compared in their ability to scavenge peroxyl radicals generatcd by the thermal decomposition of the lipid-soluble azo-initiator 2,2'-azo-bis(2,4-dimethyl-valeronitrile), AMVN, in dioleoylphos-phatidylcholine (DOPC) liposomes. Probucol showed 15-times lower peroxyl radical scavenging efficiency than x-tocopherol as measured by the effects on AMVN-induced luminol-dependent chemiluminescence. We suggest that probucol cannot protect x-tocopherol against its loss in the course of oxidation, although probucol is known to prevent lipid peroxidation in membranes and lipoproteins. In human low density lipoproteins (LDL) ESR signals of the probucol phenoxyl radical were detected upon incubation with lipoxygenase + linolenic acid or AMVN. Ascorbate was shown to reduce probucol radicals. Dihydro-lipoic acid alone was not able to reduce the probucol radical but in the presence of both ascorbate and dihydrolipoic acid a synergistic effect of a stepwise reduction was observed. This resulted from ascorbate-dependent reduction of probucol radicals and dihydrolipoic acid-dependent reduction of ascorbyl radicals. The oxidized form of dihydrolipoic acid, thioctic acid, did not affect probucol radicals either in the presence or in the absence of ascorbate.     

Structure and mechanism of Helicobacter pylori fucosyltransferase. A basis for lipopolysaccharide variation and inhibitor design

Helicobacter pylori alpha1,3-fucosyltransferase (FucT) is involved in catalysis to produce the Lewis x trisaccharide, the major component of the bacteria's lipopolysaccharides, which has been suggested to mimic the surface sugars in gastric epithelium to escape host immune surveillance. We report here three x-ray crystal structures of FucT, including the FucT.GDP-fucose and FucT.GDP complexes. The protein structure is typical of the glycosyltransferase-B family despite little sequence homology. We identified a number of catalytically important residues, including Glu-95, which serves as the general base, and Glu-249, which stabilizes the developing oxonium ion during catalysis. The residues Arg-195, Tyr-246, Glu-249, and Lys-250 serve to interact with the donor substrate, GDP-fucose. Variations in the protein and ligand conformations, as well as a possible FucT dimer, were also observed. We propose a catalytic mechanism and a model of polysaccharide binding not only to explain the observed variations in H. pylori lipopolysaccharides, but also to facilitate the development of potent inhibitors.     

Mesenchymal stem/progenitor cells developed in cultures from UC blood

Background Whether umbilical cord blood (UCB) serves as a source of mesenchymal stem/progenitor cells (MSPC) is controversial. MSPC are the best candidates for cellular therapy of orthopedic skeletal tissues. In order to explore the possibility of UCB as a useful source of MSPC, we identified, expanded in culture, and characterized MSPC from UCB harvests on a large scale. Methods Mononuclear cells isolated from UCB harvests (n=411) were cultured in media supplemented with 10% FBS. MSPC-like cells cultured from each UCB harvest were expanded ex vivo by successive subcultivation. UCB harvests with a more than 1000-fold expanding capacity (n=9) were examined for surface Ag phenotypes and in vitro differentiation potentials into osteogenic, chondrogenic and adipogenic lineages. Results Ninety-five out of a total of 411 UCB units (23.1%) generated MSPC-like cells during cultivation. Nine UCB units (2.2%) yielded MSPC with more than 1000-fold expansion capacity. These cells positively expressed MSPC-related Ag, but did not express myeloid, histocompatibility or endothelial Ag. These cells also possessed multiple capacities for osteogenic, chondrogenic and adipogenic differentiation. Discussion Although the incidence of UCB harvests producing MSPC in culture was low, some of them showed a more than 1000-fold expanding capacity, which is enough in cell numbers to be an allogeneic source for cellular therapy. Our results may encourage the use of UCB as an attractive target for allogeneic cellular therapeutic options in tissue engineering.     

Comparison of folate quantification in foods by high-performance liquid chromatography-fluorescence detection to that by stable isotope dilution assays using high-performance liquid chromatography-tandem mass spectrometry

A comparison study on folate quantitation was carried out between the recently developed stable isotope dilution assay using liquid chromatography-tandem mass spectrometry (LC-MS-MS) and the frequently used HPLC with fluorimetric detection (LC-FD). By applying LC-MS-MS, spinach, wheat bread, beef, and blood plasma were found to contain 159.2, 19.8, 1.2, and 5.6 microg/100 g total folates, respectively, whereas the respective quantitative data obtained by LC-FD were 95.5, 16.2, 0.7, and 6.8 microg/100 g. In all samples, LC-MS-MS revealed superior selectivity and precision and circumvented the shortcomings of conventional LC techniques, i.e., ambiguous peak assignment as well as high detection limits for 5-formyltetrahydrofolate, 10-formylfolic acid, and folic acid. The affinity chromatography columns used in this study showed excellent cleanup performance and permitted detection limits as low as 0.1, 0.5, 0.1, 0.08, and 0.1 microg/100 g for tetrahydrofolate (H(4)folate), 5-methyl-H(4)folate, 5-formyl-H(4)folate, 10-formylfolate, and pteroylglutamic acid, respectively. Thus, a 10-fold higher sensitivity compared to solid-phase anion-exchange cartridges was achieved. However, affinity chromatography columns revealed a significantly higher affinity toward the natural vitamers than to the racemic isotopomeric standards, which has to be considered when applying the latter in stable isotope dilution assays.     

The structural interpretations of residue Ser297 in catalytic efficiency of Escherichia coli phenylalanine aminotransferase

Escherichia coli phenylalanine aminotransferase (ecPheAT) catalyzes the biosynthesis of phenylalanine and tyrosine. The crystal structure of ecPheAT was determined in our previous study. The comparison of the 3-D structure of several aminotransferases revealed that the residue at position 297 plays an important role in enzyme function. Analysis of activities and kinetic parameters of wild type and mutant ecPheATs suggested that the residue Ser(297) was structurally selected for better catalytic efficiency. Computational modeling of ecPheAT mutants further suggested that Ser in position 297 could make ecPheAT easy with change of conformation from open form to closed form.     

Redifferentiation of dedifferentiated human chondrocytes in high-density cultures

The ommatidia in the ventral two-thirds of the compound eye of male Pieris rapae crucivora are not uniform. Each ommatidium contains nine photoreceptor cells. Four cells (R1-4) form the distal two-thirds of the rhabdom, four cells (R5-8) approximately occupy the proximal one-third of the rhabdom, and the ninth cell (R9) takes up a minor basal part of the rhabdom. The R5-8 photoreceptor cells contain clusters of reddish pigment adjacent to the rhabdom. From the position of the pigment clusters, three types of ommatidia can be identified: the trapezoidal (type I), square (type II), and rectangular type (type III). Microspectrophotometry with an epi-illumination microscope has revealed that the reflectance spectra of type I and type III ommatidia peak at 635 nm and those of type II ommatidia peak at 675 nm. The bandwith of the reflectance spectra is 40-50 nm. Type II ommatidia strongly fluoresce under ultra-violet and violet epi-illumination. The three types of ommatidia are randomly distributed. The ommatidial heterogeneity is presumably crucial for color discrimination.