Stabilization of mesophilic Allochromatium vinosum cytochrome c′ through specific mutations modeled by a thermophilic homologue

AVCP cytochrome c′ from mesophilic Allochromatium vinosum exhibits lower stability than a thermophilic counterpart, Hydrogenophilus thermoluteolus cytochrome c′ (PHCP), in which the six specific amino acid residues that are not conserved in AVCP are responsible for its stability. Here we measured the stability of AVCP variants carrying these specific residues instead of the original AVCP ones. Among the six single AVCP variants, all of which formed a dimeric structure similar to that of the wild-type, three were successfully stabilized compared with the wild-type, while one showed lower stability than the wild-type. In addition, the most stabilized and destabilized AVCP variants could bind CO, similar to the wild-type. These results indicated that mesophilic AVCP could be stabilized through specific three mutations modeled by the thermophilic counterpart, PHCP, without changing the CO binding ability.     

Molecular characterization of thyroid hormone receptors from the leopard gecko, and their differential expression in the skin

Thyroid hormones (THs) play crucial roles in various developmental and physiological processes in vertebrates, including squamate reptiles. The effect of THs on shedding frequency is interesting in Squamata, since the effects on lizards are quite the reverse of those in snakes: injection of thyroxine increases shedding frequency in lizards, but decreases it in snakes. However, the mechanism underlying this differential effect remains unclear. To facilitate the investigation of the molecular mechanism of the physiological functions of THs in Squamata, their two specific receptor (TRalpha and beta) cDNAs, which are members of the nuclear hormone receptor superfamily, were cloned from a lizard, the leopard gecko, Eublepharis macularius. This is the first molecular cloning of thyroid hormone receptors (TRs) from reptiles. The deduced amino acid sequences showed high identity with those of other species, especially in the C and E/F domains, which are characteristic domains in nuclear hormone receptors. Expression analysis revealed that TRs were widely expressed in many tissues and organs, as in other animals. To analyze their role in the skin, temporal expression analysis was performed by RT-PCR, revealing that the two TRs had opposing expression patterns: TRalpha was expressed more strongly after than before skin shedding, whereas TRbeta was expressed more strongly before than after skin shedding. This provides good evidence that THs play important roles in the skin, and that the roles of their two receptor isoforms are distinct from each other.     

Cloning of a<Emphasis Type="Italic"> decapentaplegic</Emphasis> orthologue from the sawfly,<Emphasis Type="Italic"> Athalia rosae</Emphasis> (Hymenoptera), and its expression in the embryonic appendages

The cDNA of a decapentaplegic (dpp) orthologue from the sawfly, Athalia rosae (Hymenoptera), was cloned and characterized. The clone (Ar dpp) was 2,566 bp long and encoded 395 amino acids in a single open reading frame. Genomic Southern blotting showed that Ar dpp is a single copy gene. The deduced amino acid sequence can be aligned along its entire length with known insect DPPs. It shared common characteristics such as a signal sequence, a pro-domain region, and a ligand domain with seven cysteines at conserved locations. Ar dpp was expressed as a single 5.0-kb mRNA in embryos, larvae, pupae and adults. In situ hybridization showed that Ar dpp was expressed in the dorsal region proper in early embryonic stages and in the embryonic appendages of cephalic segments (labrum, antenna, mandible, maxilla, and labium), thoracic segments (thoracic legs), and all abdominal segments except the tenth segment (pleuropodia and proleg primordia). The present results indicate that Ar dpp expression reflects the primary determination of embryonic appendages.Edited by D. TautzThe sequence reported in this paper has been deposited in the DDBJ/EMBL/GenBank database with the accession number AB121072     

Reduced pain hypersensitivity and inflammation in mice lacking microsomal prostaglandin e synthase-1

We examined the in vivo role of membrane-bound prostaglandin E synthase (mPGES)-1, a terminal enzyme in the PGE2-biosynthetic pathway, using mPGES-1 knockout (KO) mice. Comparison of PGES activity in the membrane fraction of tissues from mPGES-1 KO and wild-type (WT) mice indicated that mPGES-1 accounted for the majority of lipopolysaccharide (LPS)-inducible PGES in WT mice. LPS-stimulated production of PGE2, but not other PGs, was impaired markedly in mPGES-1-null macrophages, although a low level of cyclooxygenase-2-dependent PGE2 production still remained. Pain nociception, as assessed by the acetic acid writhing response, was reduced significantly in KO mice relative to WT mice. This phenotype was particularly evident when these mice were primed with LPS, where the stretching behavior and the peritoneal PGE2 level of KO mice were far less than those of WT mice. Formation of inflammatory granulation tissue and attendant angiogenesis in the dorsum induced by subcutaneous implantation of a cotton thread were reduced significantly in KO mice compared with WT mice. Moreover, collagen antibody-induced arthritis, a model for human rheumatoid arthritis, was milder in KO mice than in WT mice. Collectively, our present results provide unequivocal evidence that mPGES-1 contributes to the formation of PGE2 involved in pain hypersensitivity and inflammation.     

New convulsive compounds,brasiliamides A and B,from Penicillium brasilianum batista JV-379

New convulsive compounds, brasiliamides A (1) and B (2), were isolated by activity-guided fractionation from okara fermented with a soil isolate of Penicillium brasilianum Batista JV-379. Their structures were elucidated on the basis of spectral and chemical evidence and by X-ray crystallography of the hydrogenated product of 2. In the 1H- and 13C-NMR spectra of 2, the signals were complicated, all being doubled or broadened in several deuterated solvents at room temperature. The conformational change of 2 was clarified as the rotational isomerization of amide bonds in solution by NMR measurements at various temperatures. Four rotamers of 2 at two amide bonds were presented at -60 degrees C in CDCl3, whereas only two isomers were apparent at room temperature, owing to rapid rotation of one of the amide bonds. Brasiliamides A and B respectively showed convulsive activity against silkworms with ED50 values of 300 and 50 microg/g of diet.     

Molecular phylogeography of domesticated barley traces expansion of agriculture in the Old World

Barley (Hordeum vulgare ssp. vulgare) was first cultivated 10,500 years ago in the Fertile Crescent and is one of the founder crops of Eurasian agriculture. Phylogeographic analysis of five nuclear loci and morphological assessment of two traits in >250 domesticated barley accessions reveal that landraces found in South and East Asia are genetically distinct from those in Europe and North Africa. A Bayesian population structure assessment method indicates that barley accessions are subdivided into six clusters and that barley landraces from 10 different geographical regions of Eurasia and North Africa show distinct patterns of distribution across these clusters. Using haplotype frequency data, it appears that the Europe/North Africa landraces are most similar to the Near East population (F ST = 0.15) as well as to wild barley (F ST = 0.11) and are strongly differentiated from all other Asian populations (F ST = 0.34-0.74). A neighbor-joining analysis using these F ST estimates also supports a division between European, North African, and Near East barley types from more easterly Asian accessions. There is also differentiation in the presence of a naked caryopsis and spikelet row number between eastern and western barley accessions. The data support the differential migration of barley from two domestication events that led to the origin of barley--one in the Fertile Crescent and another farther east, possibly at the eastern edge of the Iranian Plateau--with European and North African barley largely originating from the former and much of Asian barley arising from the latter. This suggests that cultural diffusion or independent innovation is responsible for the expansion of agriculture to areas of South and East Asia during the Neolithic revolution.     

NESTMATE RECOGNITION AND KIN RECOGNITION IN ANTS

Abstract  All ants (Hymenoptera, Formicidae) are highly eusocial insects that are characterized by reproductive division of labor with sterile castes (worker and soldier) helping fertile castes (queen and male) to reproduce.
Ant societies, like other complex animal societies, have developed a sophisticated communication system, in which recognition behaviors are frequently involved Recognition abilities allow individuals to orient and modulate their behaviors effectively and appropriately in response to the characteristics andlor signals expressed by other organisms. Among recognition behaviors, nestmate recognition and kin recognition mechanisms have attracted great attention of sociobiologists, ecologists, insect physiologists and biochemists since 1970's. This is parallel with the popularization of Hamilton's kin selection theory. The present paper aims at reviewing the current understanding on nestmate/kin recognition in ants. This review consists of three parts. The first part concerns the diversity of recognition behaviors and their ecological implications with emphasis on nestmatelkin recognition; in the second part, the current understandings on the mechanism of nestmatelkin recognition are outlined; and in the third part, we discuss the ontogenetic development of nestmate recognition behavior and naturally mixed colonies. The study of the integration mechanism of social parasite may provide heuristic clues to the understanding of kin/nestmate recognition system.     

Expression and localization of aquaporins in rat gastrointestinal tract

A family of water-selective channels, aquaporins (AQP), has beendemonstrated in various organs and tissues. However, the localizationand expression of the AQP family members in the gastrointestinal tracthave not been entirely elucidated. This study aimed to demonstrate theexpression and distribution of several types of the AQP family and tospeculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1-5 and AQP8 was examined in various portions through the gastrointestinal tract.AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon,and their expression was relatively intense in the small intestine andcolon. In contrast, AQP4 mRNA was selectively expressed in the stomachand small intestine and AQP8 mRNA in the jejunum and colon.Immunohistochemistry and in situ hybridization demonstrated cellularlocalization of these AQP in these portions. AQP1 was localized onendothelial cells of lymphatic vessels in the submucosa and laminapropria throughout the gastrointestinal tract. AQP3 was detected on thecircumferential plasma membranes of stratified squamous epithelialcells in the esophagus and basolateral membranes of cardiac glandepithelia in the lower stomach and of surface columnar epithelia in thecolon. However, AQP3 was not apparently detected in the smallintestine. AQP4 was present on the basolateral membrane of the parietalcells in the lower stomach and selectively in the basolateral membranesof deep intestinal gland cells in the small intestine. AQP8 mRNAexpression was demonstrated in the absorptive columnar epithelial cellsof the jejunum and colon by in situ hybridization. These findings mayindicate that water crosses the epithelial layer through these waterchannels, suggesting a possible role of the transcellular route forwater intake or outlet in the gastrointestinal tract.