Efficient purification of somatomedin-C/insulin-like growth factor I using immunoaffinity chromatography

Somatomedin-C/insulin-like growth factor I was purified from human plasma using a monoclonal antibody affinity column. Combining immunoaffinity chromatography with standard protein purification methods resulted in an overall recovery of 18%. The 35 micrograms of somatomedin-C/insulin-like growth factor I purified from 500 ml of plasma appeared as a single band when analyzed by polyacrylamide gel electrophoresis and could be used in radioimmunoassay and receptor binding studies.     

Inhibition of forskolin-stimulated cardiac adenylate cyclase activity by short-chain alcohols

The diterpene forskolin stimulated rat cardiac adenylate cyclase activity at least 20-fold and potentiated the effect of NaF. The stimulatory effect of forskolin was reduced in the presence of Gpp(NH)p. Ethanol markedly reduced the stimulation of adenylate cyclase by forskolin while potentiating NaF and Gpp(NH)p stimulation. The inhibitory effect of ethanol on forskolin stimulation appeared to be of a mixed type with both a competitive and a non-competitive component. Three other short-chain linear alcohols (methanol, propanol, butanol) also inhibited forskolin-stimulation, this effect being proportional to the number of carbon atoms.     

Hormonal regulation of insulin-like growth factor I secretion by bovine adrenal cells

The role of insulin-like growth factor I (IGF-I) on the specific function of several steroidogenic cells has been recently reported. Since IGF-I is produced by several tissues, we have investigated whether bovine adrenal cells secrete this peptide. Purification of conditioned medium from adrenal cells incubated with [35S]methionine through affinity chromatography (monoclonal anti-IGF-I antibody), high pressure liquid chromatography, and polyacrylamide gel electrophoresis revealed a single band of similar Mr as pure recombinant IGF-I. Moreover, the purified adrenal-secreted IGF-I displaced bound 125I-IGF-I to its adrenal receptors, and pretreatment of adrenal cells with the purified peptide enhanced the acute corticotropin (ACTH)-induced cAMP production as recombinant IGF-I. The basal secretion of IGF-I (6 +/- 1 ng/48 h/10(6) cells) was stimulated 3-, 4.5-, and 9.5-fold by fibroblast growth factor, angiotensin II (A-II), and ACTH, respectively, but not by growth hormone. The stimulatory effects of A-II and ACTH were dose-dependent (ED50 congruent to 2.5 x 10(-8) and 1.5 x 10(-10) M, respectively), and the effects of both hormones were additive. Glucocorticoids were not the mediators of the effect of the two hormones on IGF-I secretion, since inhibition of their steroidogenic action by aminoglutethimide did not significantly modify IGF-I secretion. An immunoreactive IGF-I material was also secreted by mouse adrenal tumor cell line Y-1, but the stimulatory effect of ACTH was only 2-fold, and there was no effect of A-II. Since bovine adrenal cells contain specific IGF-I receptors and this peptide is required for the maintenance of some adrenal cell-specific function, the present data suggest that IGF-I may act in an autocrine fashion to stimulate adrenal cell differentiation stimulated by ACTH and A-II.     

The OLA major histocompatibility complex of sheep. Genetic frequencies compared in Prélpe sheep with and without scrapie

The OLA genic frequencies were studied in both normal "Préalpe" Sheep and those affected with Scrapie. In the non-affected Sheep of contaminated flocks, frequencies were generally decreased, compared with frequencies of the same factors in sick Sheep or in non-infected controls. Three OLA-A genes significantly decreased; at this locus, results in "Préalpe" and "Ile-de-France" Sheep were inversed. This observation excludes OLA genes being involved in pathogeny or resistance to the disease, but suggests the existence of a linkage between the OLA loci and at least one resistance or susceptibility locus.     

Monitoring DNA cytometric parameters during the course of chronic myelogenous leukemia.

The prognostic value of three DNA cytometric parameters--stemline ploidy (STL), stemline shoulder fraction (SSF) and "proliferative" fraction (PRF)--for the prediction of disease transformation and survival was examined for 20 patients with chronic myelogenous leukemia (CML) during the course of their disease and compared with two commonly used hematologic parameters (degree of leukocytosis and percentage of circulating leukemic progenitor cells). With disease progression, STL and SSF increased significantly, whereas PRF showed a steady decrease from diagnosis to blast crisis. The most significant part of these changes took place during the chronic phase, before the clinical onset of disease transformation. Hematologic parameters, in comparison, revealed significant changes later, shortly before blast crisis. The remaining duration of the chronic phase diminished from 25.5 months at the time of diagnosis, when the median STL was 2.0c, to 19.6 months for patients showing an STL of 2.1c, to 15.0 months with an STL of 2.2c and to 1.0 months for those with an STL of greater than or equal to 2.3c. Prognostically relevant limits for SSF and PRF were at 20%. When the SSF passed this limit or the PRF fell below it, the mean remaining chronic phase of these patients amounted to only 14.1 and 10.1 months. Interactive cytometry allows analysis of the DNA cytometric equivalent of changes in leukemic progenitor cells, which are well known from cytogenetic and cell kinetic studies. These three DNA cytometric parameters reflect the "natural history" of CML with the development of a cytogenetically hyperdiploid clone during disease progression in most patients and a simultaneous loss of proliferative potential on the level of myelobasts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibitory diffusible factor IDF45, a G1 phase inhibitor

An inhibitory diffusible factor of 45 kDa (IDF45) was isolated from medium conditioned by dense cultures of 3T3 cells. The procedure involved Bio-Gel P150 chromatography and 2 reverse-phase FPLC. After the final step of purification, 60 ng/ml of IDF45 inhibited 50% of alpha-globulin-stimulated DNA synthesis. It was shown that IDF45 acted in the G1 phase of the cell cycle. When added for 8 h in the G1 phase of the cell cycle, it was able to inhibit DNA synthesis in the S phase which followed this G1 phase. Furthermore, IDF45 inhibited the early stimulation of RNA synthesis induced by alpha-globulin.     

Deorphanization and Characterization of Human Olfactory Receptors in Heterologous Cells

Olfaction plays an indispensable role in human and animals in self and environmental recognition, as well as intra‐ and interspecific communication. Following the discovery of a family of olfactory receptors (ORs) by Buck and Axel in 1991, it has been established that the sense of smell begins with the molecular recognition of a chemical odorant by one or more ORs expressed in the olfactory sensory neurons. Therefore, characterization of the molecular interactions between odorant molecules and ORs is a key step in the elucidation of the general properties of the olfactory system and in the development of applications, i.e., design of new odorants, search for blockers, etc. The process putted in place at ChemCom to improve the expression of ORs at the cytoplasmic membrane of the HEK293 cell and assays enabling large‐scale deorphanization, and to characterize the interaction between chemical odorants and ORs is described. The family of human ORs includes ca. 400 putatively functional ORs which are GPCRs (G protein‐coupled receptors); to date over 100 human ORs have been deorphanized.     

Effect of a diazafluoranthen derivative on phospholipases A study at the air-water interface

AC-3579 (2-N-methylpiperazinomethyl-1,3-diazafluoranthen 1-oxide) produces in rat hepatocytes a hypertrophy of the endoplasmic reticulum.Two possibilities that can explain this phenomenon are (1) that AC-3579 inactivates the phospholipases, and (2) that an AC-3579-lipid interaction hinders the enzymic activity.To demonstrate these hypotheses, a physicochemical model of biological membrane, the lipid-water interface, has been used. Dipalmitoyl dl-α-phosphatidylcholine was spread at the air-water interface, the enzymes (phospholipase A or phospholipase C) dissolved in the aqueous phase.The enzymic reaction was first studied with and without AC-3579 dissolved in the aqueous phase; no enzymic inactivation was observed. However in AC-3579- lipid complex completely inhibited the enzymic reaction in the case of phospholipase A.An explanation is given in terms of steric hindrance to the enzyme-substrate complex formation.     

A DNA Metabarcoding Study of a Primate Dietary Diversity and Plasticity across Its Entire Fragmented Range

In tropical regions, most primary ecosystems have been replaced by mosaic landscapes in which species must cope with a large shift in the distribution of their habitat and associated food resources. Primates are particularly vulnerable to habitat modifications. Most species persist in small fragments surrounded by complex human-mediated matrices whose structure and connectivity may strongly influence their dispersal and feeding behavior. Behavioral plasticity appears to be a crucial parameter governing the ability of organisms to exploit the resources offered by new matrix habitats and thus to persist in fragmented habitats. In this study, we were interested in the dietary plasticity of the golden-crowned sifaka (Propithecus tattersalli), an endangered species of lemur, found only in the Daraina region in north-eastern Madagascar. We used a DNA-based approach combining the barcoding concept and Illumina next-generation sequencing to (i) describe the species diet across its entire range and (ii) evaluate the influence of landscape heterogeneity on diet diversity and composition. Faeces from 96 individuals were sampled across the entire species range and their contents were analyzed using the trnL metabarcoding approach. In parallel, we built a large DNA reference database based on a checklist of the plant species of the Daraina region. Our results suggest that golden-crowned sifakas exhibit remarkable dietary diversity with at least 130 plant species belonging to 80 genera and 49 different families. We highlighted an influence of both habitat type and openness on diet composition suggesting a high flexibility of foraging strategies. Moreover, we observed the presence of numerous cultivated and naturalized plants in the faeces of groups living in forest edge areas. Overall, our findings support our initial expectation that P. tattersalli is able to cope with the current level of alteration of the landscape and confirm our previous results on the distribution and the dispersal ability of this species.