Interaction between gabaergic and opioid pathways in the regulation of gonadotropin secretion in males

The effects of naloxone infusion given together with an infusion of LRH on gonadotropin secretion, were studied in 6 normal male volunteers before and after pretreatment with the GABA-transaminase inhibitor, valproic acid. In concordance with previous studies, naloxone infusion augmented the LRH-stimulated secretion of LH. Baseline serum LH concentrations were not significantly different after valproic acid pretreatment compared to control values. Similarly, valproic acid pretreatment failed to blunt the naloxone-augmented LRH-stimulated secretion of LH. Our data suggest that the previously reported animal studies on the central suppressive effect of GABA on endogenous LRH release is less prominent than the suppressive effect of opioidergic regulatory mechanisms in the human male.     

Sequence variations in the Fanconi anaemia gene,FAC: pathogenicity of 1806insA and R548X and recognition of D195V as a polymorphic variant

Fanconi anaemia (FA) is a rare autosomal recessive disorder associated with diverse clinical symptoms, increased chromosomal instability and a marked hypersensitivity to crosslinking agents. At least five complementation groups have been defined, the gene for group C (FAC) being the only FA gene cloned thus far. Several sequence variations have been detected in FA patients, whose assignment to group C, however, had not been ascertained by complementation studies. Using a functional assay, in which we tested the capacity of a variant sequence to correct the defect in FA-C lymphoblasts, we provide evidence for the pathogenic status of 1806insA and R548X and for non-pathogenicity of D195V. Received: 23 April 1996     

Heterogenized polymetallic catalysts Part II. Oxidation of 3,5-di-t-butylphenol by Cu(II), Fe(III) and Pd(II) complexed to a polyphenylene polymer containing ß-di- and triketone surface ligands; an improved catalyst system

Polyphenylene polymer preparation involves the cyclic trimerization polymerization of acetylated methyl benzoate with diacetyl benzene. Since the methyl benzoate groups do not take part in the polymerization they are present in high concentration. The ß-diketone ligands were placed on the surface by reaction of the methylbenzoate group with base and a methyl ketone and the triketone by reaction with base to give the ß-triketone. The ß-triketones can bind two metal ions in a known geometry that is suitable for bimetallic catalysis of the rapid polyelectron oxidation of catechols. The final catalytic surfaces were prepared by treating the chemically modified polymer with copper(II), iron(II) and palladium(II) acetonitrile complexes with non-coordinating BF₄⁻ as the anion. Since the metal ions contain no strongly coordinating ligand, they are very reactive species. These surfaces catalyzed the rapid air oxidation of 3,5-di-tert-butylcatechol (DTBC). The diketone surfaces gave only 3,5-di-tert-butyl-o-quinone (DTBQ) while the triketone surfaces gave ring-cleaved products, confirming the special catalytic effect of the triketone surface. Also, only the triketone catalysts showed any activity for ring cleavage oxidation of DTBQ. These catalysts were much more reactive than previous ones using the same polyphenylene polymer but without the methyl benzoate groups. With these polymers the di- and triketone groups were placed on the surface by chemical modification of the unpolymerized acetyl groups.     

Filamentous vibriophage fs2 encoding the rstC gene integrates into the same chromosomal region as the CTX phage [corrected]

The genome of the filamentous phage of Vibrio cholerae fs2 was found to contain rstC and rstB1 (truncated) genes downstream of ORF500. att-fs2-dir and att-fs2-rev sequences homologous to that of att-CTXphi were found between orf500 and rstC of the fs2 genome. This prompted us to search for the integration site of fs2 in the genomes of V. cholerae O1 and O139. The genome of fs2 was found to integrate downstream of attRS of the CTXphi phage, which integrated into chromosome I of V. cholerae O1 and O139. When infected with fs2, a fimbriate strain of V. cholerae O1 appeared to reduce fimbrial production in an adult rabbit ileal loop assay.     

Effect of willow cultivar and plant age on the melezitose content of giant willow aphid (Tuberolachnus salignus) honeydew

1. The giant willow aphid Tuberolachnus salignus is an invasive pest in New Zealand, attacking over 50 species and hybrids of willow. The aphids produce copious amounts of honeydew, which is used by other insects as a food source.
2. When foraged by honeybees, T. salignus honeydew causes honey to crystallize in the comb and affects bee health; these effects are associated with the elevated melezitose content in the honeydew. The impact of host plant-related factors on T. salignus honeydew melezitose content remains unknown.
3. This study investigated the effect of willow cultivar and plant age on the melezitose content (and that of other sugars) of T. salignus honeydew. To do so, we conducted high-performance liquid chromatography analyses of honeydew samples from 13 willow clones collected in the same season (autumn) from 1- and 2-year old plants under field conditions.
4. Melezitose was the most abundant of the measured sugars in most samples, but its content did not vary significantly with willow cultivar or plant age. By contrast, sucrose was significantly affected by both factors. Fructose and glucose were significantly impacted by willow plant age and cultivar, respectively. A significant cultivar*age interaction was observed for all sugars.
5. We recommend the selection of resistant willow cultivars and further research on potential biocontrol agents to lessen melezitose-related problems in apiculture industries.

     

A methionine-Mettl3-N6-methyladenosine axis promotes polycystic kidney disease

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Notes on some rust fungi in Vietnam

Sixteen rust species and two unconnected Peridermium collected in Vietnam are enumerated. For all the rust species except Hemileia vastarix, Olivea tectonae, and Puccinia thwaitesii, these are the first records of their occurrence in Vietnam. Some taxonomic and pathological considerations are noted for two economically important pine stem rusts.