Changes in quinolinic acid production and its related enzymes following D-galactosamine and lipopolysaccharide-induced hepatic injury

Increases in quinolinic acid (QUIN), a neurotoxic L-tryptophan metabolite, have been observed in human serum and cerebrospinal fluid and in animal models of severe hepatic injury. The aim of this study was to evaluate the changes in QUIN accumulation and its related enzymes after acute hepatic injury induced by D-galactosamine and endotoxin. Gerbils were given an intraperitoneal injection of pyrogen-free saline alone as control, lipopolysaccharide (LPS) alone (150 ng/kg), D-galactosamine alone (500 mg/kg) or a combination of D-galactosamine with LPS. Concentrations of QUIN, its related metabolites, and related enzyme activities were determined. D-Galactosamine treatment significantly decreased activities of hepatic aminocarboxymuconate-semialdehyde decarboxylase (ACMSDase) resulting in increased QUIN concentrations in serum and tissues. The magnitude of QUIN responses was markedly increased by endotoxin due to the increased availability of L-kynurenine, a rate-limiting substrate for QUIN synthesis. Further, infiltration of monocytes/macrophages, which is a possible major source of QUIN production in the liver, was shown by immunohistochemistry after hepatic injury induced by D-galactosamine and endotoxin. Increased serum QUIN concentrations are probably due to the increased substrate availability and the decreased activity of aminocarboxymuconate-semialdehyde decarboxylase in the liver, accompanying the increased monocyte/macrophage infiltration into the liver after hepatic injury.     

Cellular distribution of parchorin, a chloride intracellular channel-related protein, in various tissues

The cellulardistribution of parchorin, a new chloride intracellular channel familymember, was investigated in rabbit tissues by immunohistochemistryusing an antibody recognizing the sequence containing aparchorin-specific repeat. Parchorin preferentially resides in theepithelium of the ducts of the lacrymal, parotid, submandibular, andmammary glands and the pancreas, prostate, and testis. In the tracheaand lung, parchorin was found in the airway epithelium and type IIalveolar cells. In the kidney, parchorin was distributed mainly fromthe thick ascending limb to the distal convoluted tubule. In the eye,both pigment and nonpigment epithelia of the ciliary body werepositive, whereas only the pigment epithelium was positive in theretina. Parchorin was also present in the cochlea and semicircularcanal. The amount of parchorin in the gastric mucosa, but not in thesubmandibular glands, increased after weaning. In the mammary gland,parchorin expression was greater in a lactating rabbit (1 wk afterdelivery) compared with a pregnant (3 wk) rabbit. The cellulardistribution and changes in expression indicate that parchorin plays animportant role, possibly in chloride transport, in the cells thatcreate an ion gradient for water movement.

     

Lectin binding pattern in normal human labial mucosa

Summary The pattern of lectin binding in normal human labial mucosa was examined by light and electron microscopy using eight different lectins (ConA, LCA, WGA, UEA-1, RCA-1, SBA, DBA and PNA) and compared with the patterns in normal human skin and oesophageal mucosa. As seen by light microscopy, ConA, LCA, and WGA stained cell membranes in all layers of the mucosae. RCA-1 stained the plasma membrane of cells in the basal and middle layers, whereas cells in the superficial layers showed little positive staining. UEA-1, SBA, and PNA stained the cells in the middle layers weakly in some cases. No positive staining for DBA was seen. By electron microscopy, reaction product indicating ConA-binding sites was observed in the plasma membrane, cisternae of the endoplasmic reticulum, nuclear envelope and the Golgi apparatus. Binding of LCA, WGA, and RCA-1 was observed in the plasma membrane. These results show that the binding pattern of PNA, SBA, and RCA-1 in labial mucosa is different from that in the normal skin or oesophageal mucosa, although the labial mucosal epithelium, epidermis, and oesophageal epithelium are all stratified squamous epithelia. These differences in the cell-surface sugar residues are likely to be related to the possible functional differences in these tissues.     

Relief effect of vitamin A on the decreased motility of sperm and the increased incidence of malformed sperm in mice exposed neonatally to bisphenol A

Administration of 50 g of bisphenol A (BPA) for the first 5 days after birth resulted in a decrease in the percentage of moving sperm, and an increase in the incidence of malformed sperm, in the epididymides of mice at 10 weeks of age, although no marked changes were found in the testicular histology between BPA-treated and vehicle-treated control mice. The deteriorating effects of 50 g of BPA were ameliorated by the concurrent administration of 100 IU of retinol acetate (RA). Neonatal treatment with 0.5 g of BPA for 5 days resulted in an increase in the incidence of malformed sperm, whereas the BPA effect became more severe in mice nursed by mothers fed a vitamin A-deficient (VAD) diet only a few days before and after parturition. On the other hand, neonatal treatment with 20 g of estrogen for the first 5 days after birth resulted in an increase in the number of estrogen receptor (ER)-positive cells in the epithelium of the vas deferens, whereas only a few epithelial cells showed weak ER-positive signals in the vehicle-treated control mice at 18 days after birth. This increase, however, was suppressed by the concurrent administration of RA. Although five daily treatments with 50 g BPA led to no significant increase in the number of ER-positive cells, it may have been due to the weak estrogenic activity of BPA, as discussed. These findings clearly showed that in mice, neonatal exposure to a relatively large dose of BPA causes damage to the motility and morphology of sperm, but the BPA effect is, to some extent, inhibited by a supplement of VA, and enhanced under a VAD condition.This work was supported by Grants-in-Aid for Encouragement of Young Scientists, Scientific Research (C) and Scientific Research on Priority Areas (A) from the Ministry of Education, Science, Sports, and Culture, Japan     

Ligand-binding properties of annexin from Caenorhabditis elegans (annexin XVI, Nex-1)

Annexins are structurally related proteins that bind phospholipids in a calcium-dependent manner. Recently, we showed that annexins IV, V, and VI also bind glycosaminoglycans in a calcium-dependent manner. Annexins are widely distributed from lower to higher eukaryotes, and the nematode Caenorhabditis elegans has been found to contain Nex-1, an annexin homologue. Here, we characterize the ligand-binding properties of Nex-1 using recombinant Nex-1. Nex-1 binds to liposomes containing phosphatidylserine. The apparent K(d) was calculated by Biacore to be 4.4 nM. Compared to mammalian annexins, the Nex-1 phospholipid-binding specificities were similar whereas the K(d) values were one order of magnitude larger. The Nex-1 glycosaminoglycan-binding specificities were investigated by affinity chromatography and solid-phase assays. Nex-1 binds to heparin, heparan sulfate, and chondroitin sulfate but not to chondroitin and chemically N- or O-desulfated heparin. Besides phospholipids, heparan sulfate and/or chondroitin (sulfate), probably on perlecan, could be endogenous ligands of Nex-1.     

Synthetic Nucleosides and Nucleotides. 43. Inhibition of Vertebrate Telomerases by Carbocyclic Oxetanocin G (C.OXT-G) Triphosphate Analogues and Influence of C.OXT-G Treatment on Telomere Length in Human HL60 Cells

Telomerase, responsible for telomere synthesis, is expressed in ～ 90% of human tumor cells but seldom in normal somatic cells. In this study, inhibition by carbocyclic oxetanocin G triphosphate (C.OXT-GTP) and its analogues was investigated in order to clarify the susceptibility of telomerase to various nucleotide analogues. C.OXT-GTP competitively inhibited telomerase activity with respect to dGTP. However, C.OXT-GTP had a potent inhibitory effect on DNA polymerase α. It was examined whether the nucleoside (C.OXT-G) was able to alter telomere length in cultured human HL60 cells. Contrary to expectation, long-term treatment with 10 μM C.OXT-G was found to cause telomere lengthening.     

Complete genome sequence of Treponema succinifaciens type strain (6091)

Treponema succinifaciens Cwyk and Canale-Parola 1981 is of interest because this strictly anaerobic, apathogenic member of the genus Treponema oxidizes carbohydrates and couples the Embden-Meyerhof pathway via activity of a pyruvate-formate lyase to the production of acetyl-coenzyme A and formate. This feature separates this species from most other anaerobic spirochetes. The genome of T. succinifaciens 6091(T) is only the second completed and published type strain genome from the genus Treponema in the family Spirochaetaceae. The 2,897,425 bp long genome with one plasmid harbors 2,723 protein-coding and 63 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Complete genome sequence of Cellulophaga lytica type strain (LIM-21)

Cellulophaga lytica (Lewin 1969) Johansen et al. 1999 is the type species of the genus Cellulophaga, which belongs to the family Flavobacteriaceae within the phylum 'Bacteroidetes' and was isolated from marine beach mud in Limon, Costa Rica. The species is of biotechnological interest because its members produce a wide range of extracellular enzymes capable of degrading proteins and polysaccharides. After the genome sequence of Cellulophaga algicola this is the second completed genome sequence of a member of the genus Cellulophaga. The 3,765,936 bp long genome with its 3,303 protein-coding and 55 RNA genes consists of one circular chromosome and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Sensory rhodopsin-I as a bidirectional switch: opposite conformational changes from the same photoisomerization

The phototaxis receptor sensory rhodopsin I (SRI) exists in two protein conformations, each of which is converted to the other by light absorption by the protein's retinylidene chromophore. One conformer inhibits a histidine-kinase attached to its bound transducer HtrI and its formation induces attractant motility responses, whereas the other conformer activates the kinase and its formation induces repellent responses. We performed Fourier transform infrared spectroscopy with temperature, pH, and mutation-induced shifts in the conformer equilibrium, and found that both conformers when present in the unphotolyzed dark state contain an all-trans retinal configuration that is photoisomerized to 13-cis, i.e., the same photoisomerization causes the opposite conformational change in the photointerconvertible pair of conformers depending on which conformer is present in the dark. Therefore, switching between the protein global conformations that define the two conformers is independent of the direction of isomerization. Insights into this phenomenon are gained from analysis of the evolution of the receptor from light-driven proton pumps, which use similar conformers for transport. The versatility of the conformational changes of microbial rhodopsins, including conformer interexchangeability in the photocycle as shown here, is likely a significant factor in the evolution of the diverse functionality of this protein family.     

Genome sequence of Phaeobacter daeponensis type strain (DSM 23529T), a facultatively anaerobic bacterium isolated from marine sediment,and emendation of Phaeobacter daeponensis

TF-218^T is the type strain of the species Phaeobacter daeponensis Yoon et al. 2007, a facultatively anaerobic Phaeobacter species isolated from tidal flats. Here we describe the draft genome sequence and annotation of this bacterium together with previously unreported aspects of its phenotype. We analyzed the genome for genes involved in secondary metabolite production and its anaerobic lifestyle, which have also been described for its closest relative Phaeobacter caeruleus. The 4,642,596 bp long genome of strain TF-218^T contains 4,310 protein-coding genes and 78 RNA genes including four rRNA operons and consists of five replicons: one chromosome and four extrachromosomal elements with sizes of 276 kb, 174 kb, 117 kb and 90 kb. Genome analysis showed that TF-218^T possesses all of the genes for indigoidine biosynthesis, and on specific media the strain showed a blue pigmentation. We also found genes for dissimilatory nitrate reduction, gene-transfer agents, NRPS/ PKS genes and signaling systems homologous to the LuxR/I system.