Instability of serum 17 beta-hydroxysteroid dehydrogenases of placental origin

The stabilization by glycerol of the serum estradiol 17 beta dehydrogenase has been investigated here in terms of time and temperature. The protected enzyme is stable for a month at least at --20 degrees C. Its activity reaches a maximum at 60 degrees C. In another connection, effect of reduced glutathione, of N. acetyl-cysteine and of various mineral ions on the enzymic conversion has been studied.     

Enantioselective inhibitory effect of nicardipine on the hepatic clearance of propranolol in man

The influence of a single oral dose of 30 mg nicardipine on the pharmacokinetics of (R)- and (S)-propranolol, given orally as rac-propranolol 80 mg, was studied in 12 healthy volunteers. The plasma concentrations were higher for the (S)-enantiomer than for the (R)-enantiomer. The Cl_o and the Cl′_intr of (S)-propranolol were significantly lower than the Cl_o and Cl′_intr of (R)-propranolol. The unbound fraction of (R)-propranolol was significantly higher than that of (S)-propranolol. Coadministration of nicardipine significantly increased the AUC and C_max and significantly decreased the Cl_o and Cl′_intr for unbound drug of (R)- and (S)-propranolol. These changes were more important for (R)- than for (S)-propranolol. The protein binding was not altered by nicardipine. The enantioselective effect of nicardipine on the metabolic clearance of propranolol appears to be due to an interaction at the level of the metabolizing enzymes. The effect on blood pressure of rac-propranolol was little affected when nicardipine was coadministered with rac-propranolol, and its bradycardic effect was reduced. © 1994 Wiley-Liss, Inc.     

The orphan receptor cDNA RDC4 encodes a 5-HT1D serotonin receptor.

The cDNA of RDC4, a putative receptor of the G protein-coupled receptor family, has been cloned by PCR methodology. The primary structure of this receptor showed homology with the serotonin 5-HT1A receptor. In this work, RDC4 mRNA has been injected in Y1 adrenal cells and Xenopus oocytes and RDC4 cDNA has been transfected transiently in cos-7 cells. In all these systems serotonin elicited a rise in cyclic AMP levels. Binding studies on membranes of the transfected cos-7 cells using [3H]-LSD showed a pattern of drug affinities consistent with the known properties of a 5-HT1D receptor. RDC4 therefore codes for a 5-HT1D receptor which in the studied systems is positively coupled to adenylate cyclase.     

Mandibuloacral dysplasia is caused by a mutation in LMNA-encoding lamin A/C

Mandibuloacral dysplasia (MAD) is a rare autosomal recessive disorder, characterized by postnatal growth retardation, craniofacial anomalies, skeletal malformations, and mottled cutaneous pigmentation. The LMNA gene encoding two nuclear envelope proteins (lamins A and C [lamin A/C]) maps to chromosome 1q21 and has been associated with five distinct pathologies, including Dunnigan-type familial partial lipodystrophy, a condition that is characterized by subcutaneous fat loss and is invariably associated with insulin resistance and diabetes. Since patients with MAD frequently have partial lipodystrophy and insulin resistance, we hypothesized that the disease may be caused by mutations in the LMNA gene. We analyzed five consanguineous Italian families and demonstrated linkage of MAD to chromosome 1q21, by use of homozygosity mapping. We then sequenced the LMNA gene and identified a homozygous missense mutation (R527H) that was shared by all affected patients. Patient skin fibroblasts showed nuclei that presented abnormal lamin A/C distribution and a dysmorphic envelope, thus demonstrating the pathogenic effect of the R527H LMNA mutation.     

Spleen immune status is affected after acute handling stress but not regulated by cortisol in Eurasian perch,Perca fluviatilis

The effects of acute stress on immune status and its regulation by cortisol/corticosteroid receptors have received little attention in percids. To address that question, we investigated the physiological and immune responses of Eurasian perch, Perca fluviatilis to acute stress. We exposed immature perch to an 1-min exondation and measured at 1 h, 6 h, 24 h and 72 h post-stress: (1) stress-related parameters including plasma cortisol and glucose levels, (2) immune parameters in the plasma and in the spleen (complement, respiratory burst and lysozyme activity, total immunoglobulins; gene expression of lysozyme, complement unit 3, apolipoprotein A1 and 14 kDa, hepcidin and chemotaxin) (3) the corticosteroid receptors gene expression in the spleen after having cloned them. In addition, the in vitro effects of cortisol on the spleen immune parameters were also investigated.Plasma cortisol and glucose levels increased markedly 1 h post-stress and returned at basal levels after 24 h. P. fluviatilis mineralocorticoid receptor, but not glucocorticoid receptors, was significantly up-regulated both in vivo after the stress and in vitro by cortisol at a physiological concentration (100 ng/ml). The plasma immune parameters were not significantly affected by the stress. In contrast, spleno-somatic index, spleen lysozyme activity, lysozyme and hepcidin gene expression were depleted and total immunoglobulins increased along the whole time-course (1–72 h). But, these immune parameters were not regulated in vitro by cortisol at physiological or supra-physiological doses.Our results indicate that handling stress may affect spleen antibacterial defences without clear effects on circulating immune compounds and that the elevation of plasma cortisol after handling stress may not be related to the regulation of this splenic response.     

Use of molecular techniques to elucidate the mechanisms of action of fungal biocontrol agents: a review

Biological control of fungal plant pathogens appears as an attractive and realistic approach, and numerous microorganisms have been identified as biocontrol agents. There have been many efforts to understand the mechanisms of action of fungal biocontrol agents. Microbiological, microscopic, and biochemical techniques applied over many years have shed light on these mechanisms without fully demonstrating them. More recently, the development of molecular techniques has yielded innovative alternative tools for understanding and demonstrating the mechanisms underlying biocontrol properties. To date, more than 70 publications describe the use of molecular techniques for this purpose. They describe work exploiting targeted or non-targeted gene isolation, gene expression profiling, gene inactivation and/or overexpression, the study of regulatory factors. This work has shed considerable light on mechanisms underlying biocontrol properties. It has also fully demonstrated a number of targeted action mechanisms of some biocontrol agents. This review describes the techniques used in such studies, with their potential and limitations. It should provide a guide for researchers wanting to study the molecular basis of the biocontrol in diverse biocontrol agents.     

Pendrin: the thyrocyte apical membrane iodide transporter?

In the thyroid, the transport of iodide from the extracellular space to the follicular lumen requires two steps: the transport in the cell at the basal side and in the lumen at the apical side. The first step is mediated by the Na(+)/I(-) symporter (NIS). In most reviews and textbooks, the second step is presented as mediated by pendrin. In this review, we analyze this assumption. There are several arguments supporting the concept that indeed pendrin plays an important role in thyroid physiology. However, biochemical, clinical and histological data on the thyroid of a patient with Pendred syndrome do not suggest an essential role in iodide transport, which is corroborated by the lack of a thyroid phenotype in pendrin knockout mice. Experiments in vivo and in vitro on polarized and unpolarized cells show that iodide is transported transport of iodide at the apex of the thyroid cell. Moreover, ectopic expression of pendrin in transfected non-thyroid cells is capable of mediating iodide efflux. It is concluded that pendrin may participate in the iodide efflux into thyroid lumen but not as the unique transporter. Moreover, another role of pendrin in mediating Cl(-)/HCO(3)(-) exchange and controlling luminal pH is suggested.     

A numerical taxonomic study of the Pseudomonas flora isolated from poultry meat

Pseudomonas strains were isolated from both fresh and cold-stored broiler skin. Phenotypically-based numerical taxonomic techniques were used to characterize the isolates and 36 reference strains. For this purpose, Biolog GN Microplates, API 20NE and a number of other biochemical tests were used. Jaccard clustering revealed the predominance of four major Pseudomonas groups: Ps. fragi, Ps. lundensis, strains belonging to Ps. fluorescens biovars and an unidentified group of strains displaying a high degree of similarity to Ps. fluorescens biovars. Within Ps. fluorescens, biovar A was best represented. The marked proteolytic character of members of Ps. fluorescens biovars A, B and C, as well as of members of the unidentified cluster, supports their possible role in the origin of organoleptic defects. In the Ps. lundensis cluster, a distinct group of Ps. lundensis-like species was found. Further genotypic studies should be carried out to clarify the taxonomic status of the Ps. lundensis-like strains and that of the unidentified group resembling Ps. fluorescens biovars A and B.     

Lessons learned from the virus indexing of Musa germplasm: insights from a multiyear collaboration

The Bioversity International Transit Center (ITC) for banana hosts more than 1500 accessions largely covering the genetic diversity of the genus Musa. Its objective is to conserve this genetic diversity and to supply plant materials to users worldwide. All the Musa accessions must be tested for virus presence and, if infected, virus elimination must be attempted, to enable the supply of virus‐free plant material. An international collaborative effort launched under the auspices of Bioversity International (2007–2013) finally led to the implementation of a two‐step process to test the accessions. The first step, called pre‐indexing, involved only molecular tests and was designed as a pre‐screen of new germplasm lines or existing accessions to reduce the need for post‐entry virus therapy and repeated virus indexing. The second step, called full indexing, was performed on either older existing accessions or newer accessions which tested negative during pre‐indexing, and involved molecular tests, transmission electron microscopy (TEM) and symptom observation. In total, 270 germplasm lines (434 samples) were pre‐indexed; while full indexing was carried out on 243 accessions (68 of which had been pre‐indexed). A significant proportion of the samples tested during pre‐indexing was infected with at least one virus (68%), showing the utility of this early pre‐screening step. Banana streak OL virus and Banana mild mosaic virus were the most commonly detected viruses during both pre‐ and full indexing. For 22 accessions, viral particles were observed by TEM in full indexing while the molecular tests were negative, underlining the importance of combining various detection techniques. After full indexing, viruses were not detected in 166 accessions, which were then released for international distribution from the ITC. This publication exemplifies how the practical application of diagnostic protocols can raise fundamental questions related to their appropriate use in routine practice and the need for their continuous monitoring and improvement after their first publication.