Elucidation of the structure of talinolol metabolites in man determination of talinolol and hydroxylated talinolol metabolites in urine and analysis of talinolol in serum

The objective of this study was to determine the structure of talinolol metabolites formed and the amounts excreted in urine. Talinolol metabolites in urine were identified by comparing their HPLC retention times and their GC—MS profile with those of previously characterized reference compounds. The metabolites were quantified by HPLC with a normal-phase silica column, a single chloroform extraction and UV detection. Less than 1% of an administered dose was found in urine as hydroxylated talinolol. Other metabolites could be excluded. A sensitive method to determine talinolol in serum and a simple method for analysis of talinolol in urine are described. These methods were found to be precise and accurate for the measurement of talinolol in samples obtained from patients during chronic talinolol treatment as well as from healthy volunteers after a single dose of talinolol.     

New intragenic deletions in the Phex gene clarify X-linked hypophosphatemia-related abnormalities in mice

X-linked hypophosphatemic rickets (XLH) in humans is caused by mutations in the PHEX gene. Previously, three mutations in the mouse Phex gene have been reported: Phex^Hyp, Gy, and Phex^Ska1. Here we report analysis of two new spontaneous mutations in the mouse Phex gene, Phex^Hyp-2J and Phex^Hyp-Duk. Phex^Hyp-2J and Phex^Hyp-Duk involve intragenic deletions of at least 7.3 kb containing exon 15, and 30 kb containing exons 13 and 14, respectively. Both mutations cause similar phenotypes in males, including shortened hind legs and tail, a shortened square trunk, hypophosphatemia, hypocalcemia, and rachitic bone disease. In addition, mice carrying the Phex^Hyp-Duk mutation exhibit background-dependent variable expression of deafness, circling behavior, and cranial dysmorphology, demonstrating the influence of modifying genes on Phex-related phenotypes. Cochlear cross-sections from Phex^Hyp-2J/Y and Phex^Hyp-Duk/Y males reveal a thickening of the temporal bone surrounding the cochlea with the presence of a precipitate in the scala tympani. Evidence of the degeneration of the organ of Corti and spiral ganglion also are present in the hearing-impaired Phex^Hyp-Duk/Y mice, but not in the normal-hearing Phex^Hyp-2J/Y mice. Analysis of the phenotypes noted in Phex^Hyp-Duk/Y an Phex^Hyp-2J/Y males, together with those noted in Phex^Ska1/Y and Phex^Hyp/Y males, now allow XLH-related phenotypes to be separated from non-XLH-related phenotypes, such as those noted in Gy/Y males. Also, identification of the genetic modifiers of hearing and craniofacial dysmorphology in Phex^Hyp-Duk/Y mice could provide insight into the phenotypic variation of XLH in humans. *Bothauthorscontributedequallytothisresearch.     

Marine Bacteroidetes enzymatically digest xylans from terrestrial plants

Marine Bacteroidetes that degrade polysaccharides contribute to carbon cycling in the ocean. Organic matter, including glycans from terrestrial plants, might enter the oceans through rivers. Whether marine bacteria degrade structurally related glycans from diverse sources including terrestrial plants and marine algae was previously unknown. We show that the marine bacterium Flavimarina sp. Hel_I_48 encodes two polysaccharide utilization loci (PULs) which degrade xylans from terrestrial plants and marine algae. Biochemical experiments revealed activity and specificity of the encoded xylanases and associated enzymes of these PULs. Proteomics indicated that these genomic regions respond to glucuronoxylans and arabinoxylans. Substrate specificities of key enzymes suggest dedicated metabolic pathways for xylan utilization. Some of the xylanases were active on different xylans with the conserved β-1,4-linked xylose main chain. Enzyme activity was consistent with growth curves showing Flavimarina sp. Hel_I_48 uses structurally different xylans. The observed abundance of related xylan-degrading enzyme repertoires in genomes of other marine Bacteroidetes indicates similar activities are common in the ocean. The here presented data show that certain marine bacteria are genetically and biochemically variable enough to access parts of structurally diverse xylans from terrestrial plants as well as from marine algal sources.     

Biochemical properties of nematode O-acetylserine(thiol)lyase paralogs imply their distinct roles in hydrogen sulfide homeostasis

O-Acetylserine(thiol)lyases (OAS-TLs) play a pivotal role in a sulfur assimilation pathway incorporating sulfide into amino acids in microorganisms and plants, however, these enzymes have not been found in the animal kingdom. Interestingly, the genome of the roundworm Caenorhabditis elegans contains three expressed genes predicted to encode OAS-TL orthologs (cysl-1–cysl-3), and a related pseudogene (cysl-4); these genes play different roles in resistance to hypoxia, hydrogen sulfide and cyanide. To get an insight into the underlying molecular mechanisms we purified the three recombinant worm OAS-TL proteins, and we determined their enzymatic activities, substrate binding affinities, quaternary structures and the conformations of their active site shapes. We show that the nematode OAS-TL orthologs can bind O-acetylserine and catalyze the canonical reaction although this ligand may more likely serve as a competitive inhibitor to natural substrates instead of being a substrate for sulfur assimilation. In addition, we propose that S-sulfocysteine may be a novel endogenous substrate for these proteins. However, we observed that the three OAS-TL proteins are conformationally different and exhibit distinct substrate specificity. Based on the available evidences we propose the following model: CYSL-1 interacts with EGL-9 and activates HIF-1 that upregulates expression of genes detoxifying sulfide and cyanide, the CYSL-2 acts as a cyanoalanine synthase in the cyanide detoxification pathway and simultaneously produces hydrogen sulfide, while the role of CYSL-3 remains unclear although it exhibits sulfhydrylase activity in vitro. All these data indicate that C. elegans OAS-TL paralogs have distinct cellular functions and may play different roles in maintaining hydrogen sulfide homeostasis.     

The cryptic genetic structure of the North American captive gorilla population

Western lowland gorillas (Gorilla gorilla gorilla) were imported from across their geographical range to North American zoos from the late 1800s through 1974. The majority of these gorillas were imported with little or no information regarding their original provenance and no information on their genetic relatedness. Here, we analyze 32 microsatellite loci in 144 individuals using a Bayesian clustering method to delineate clusters of individuals among a sample of founders of the captive North American zoo gorilla collection. We infer that the majority of North American zoo founders sampled are distributed into two distinct clusters, and that some individuals are of admixed ancestry. This new information regarding the existence of ancestral genetic population structure in the North American zoo population lays the groundwork for enhanced efforts to conserve the evolutionary units of the western lowland gorilla gene pool. Our data also show that the genetic diversity estimates in the founder population were comparable to those in wild gorilla populations (Mondika and Cross River), and that pairwise relatedness among the founders is no different from that expected for a random mating population. However, the relatively high level of relatedness (R = 0.54) we discovered in a pair of known breeding pairs reveals the need for incorporating genetic relatedness estimates in the captive management of western lowland gorillas.     

PROLACTIN-Deficiency in Adult Offspring of Diabetic Mothers

Maternal diabetes induces fetal alterations, resulting in lasting consequences for the glucose tolerance of the offspring over several generations. In our experimental rat model, circulating prolactin, oestradiol, progesterone and corticosterone levels, known to influence insulin secretion and action, are determined in plasma of female adult offspring of mildly and severely diabetic mothers. Prolactin and progesterone levels are equally low in both groups as compared to controls, stressing the involvement of the CNS in the transgeneration effect; oestradiol and corticosterone levels are normal. No correlation is found between these hormonal alterations and the known differences in glucose tolerance.     

Heritable variation in locomotion,reward sensitivity and impulsive behaviors in a genetically diverse inbred mouse panel

Drugs of abuse, including alcohol and stimulants like cocaine, produce effects that are subject to individual variability, and genetic variation accounts for at least a portion of those differences. Notably, research in both animal models and human subjects point toward reward sensitivity and impulsivity as being trait characteristics that predict relatively greater positive subjective responses to stimulant drugs. Here we describe use of the eight collaborative cross (CC) founder strains and 38 (reversal learning) or 10 (all other tests) CC strains to examine the heritability of reward sensitivity and impulsivity traits, as well as genetic correlations between these measures and existing addiction-related phenotypes. Strains were all tested for activity in an open field and reward sensitivity (intake of chocolate BOOST®). Mice were then divided into two counterbalanced groups and underwent reversal learning (impulsive action and waiting impulsivity) or delay discounting (impulsive choice). CC and founder mice show significant heritability for impulsive action, impulsive choice, waiting impulsivity, locomotor activity, and reward sensitivity, with each impulsive phenotype determined to be non-correlating, independent traits. This research was conducted within the broader, inter-laboratory effort of the Center for Systems Neurogenetics of Addiction (CSNA) to characterize CC and DO mice for multiple, cocaine abuse related traits. These data will facilitate the discovery of genetic correlations between predictive traits, which will then guide discovery of genes and genetic variants that contribute to addictive behaviors.