Some Properties of Neutral Proteolytic System in Rabbit Skeletal Muscle

The properties of the neutral proteolytic activity concentrated in a fraction (F–1) separated from rabbit muscle homogenate were examined by measuring the effects of various reagents and metal ions, the time course of the proteolysis and Ca-stability. The obtained results have indicated that F–1 contains two types of neutral protease active on proteins, tentatively named Protease I and II, The former, which is activated by Ca²⁺ and Ca-labile, shows an explosive production of Cu-Folin phenol reagent positive materials at the early stage of incubation. The latter, which is Ca-stable, shows a large production of ninhydrin positive materials throughout the incubation time. The proteolysis by F–1 was similar to the autolysis of muscle homogenate in all the properties examined. Therefore, Proteases I and II were assumed to be main enzymes responsible for the muscle proteolysis at the neutral pH region. As there has been no factor denying their functioning in living muscle, it is probable that Proteases I and II take important parts in the muscle catabolism.     

Analysis of CLDN14 gene in deaf Moroccan patients with non-syndromic hearing loss

Mutations in the CLDN14 gene, encoding the tight junction claudin 14 protein has been reported to date in an autosomal recessive form of isolated hearing loss DFNB29. In order to identify the contribution of CLDN14 to inherited deafness in Moroccan population, we performed a genetic analysis of this gene in 80 Moroccan familial cases. Our results show the presence of 7 mutations: 6 being conservative and one leading to a missense mutation (C11T) which was found at heterozygous and homozygous states, with a general frequency of 6.87%. The pathogenicity of the resulting T4M substitution is under discussion.     

Utilisation des isotopes stables pour l’identification de l’origine du carbone dans la datation du charbon de bois du Paléolithique

Recent years have brought many results of radiocarbon dating the earliest periods of the Upper Palaeolithic that can bring light on the origins of figurative art by Sapiens or Neanderthals. These dates are often close to the limit of the field of radiocarbon dating; because they require measurements of the lowest amounts of radiocarbon, controls are particularly essential. Here we examine the case of the dating of charcoal, whose identification after decontamination is difficult. We suggest a method that does not require additional manipulation to determine whether carbon comes exclusively from charcoal: using the proportion of stable carbon isotopes 13C/12C which is often regarded as a signature (δ13C).     

The Expression of Urotensin II Receptor (U2R) is Up‐regulated by Interferon‐γ

Abstract

Urotensin‐II (U‐II) was identified as the natural ligand of the G protein‐coupled receptor GPR14, which has been correspondingly renamed Urotensin‐II receptor (U2R). The tissue distribution of U2R and the pharmacological effects of U‐II suggest a novel neurohormonal system with potent cardiovascular effects. We here report the human rhabdomyosarcoma cell line TE‐671 as the first natural and endogenous source of functional U2R in an immortalized cell line. In TE‐671 cells, U‐II stimulated extracellular signal regulated kinase phosphorylation and increased c‐fos mRNA expression. Furthermore, we demonstrate that the expression of U2R mRNA and functional U‐II high affinity binding sites are serum‐responsive and that they are specifically up‐regulated by interferon γ (IFNγ). We propose that IFNγ contributes to the previously observed increase of U2R density in the heart tissue of congestive heart failure (CHF) patients and we suggest that U2R up‐regulation, as a consequence of an inflammatory response, could lead to a clinical worsening of this disease.     

Some Observations on the Irradiance and Carbon Fixation in Grane Langsø

Photosynthetically active radiation (PAR) was registered daily in 0.25 m and 11.25 m in 3 years. Upwards irradiance of green light was 1 % of downward irradiance. Incubator ¹⁴C experiments showed that the phytoplankton enhanced its carbon uptake substantially with increasing concentrations of the carrier CO₂ in the ampoules. Severe carbon limitation of photosynthesis occurred in spring and summer 1961, where the real carbon fixation was only about 34 % of that calculated by the usual procedure. Utilization of light and DIC by the phytoplankton and its compensation depth was determined. Photoinhibition occurred down to 10–11 m, and net primary production was nearly always positive in any depth down to the lake bottom.     

Double-inducible gene activation system for caspase 3 and 9 in epidermis

Expression of genes with tight and precise temporal and spatial control is desired in a wide variety of applications ranging from cultured cells and transgenic animals to gene therapy. While current inducible systems, such as RU486 and chemical inducers of dimerization (CID), have improved earlier inducible models (Gossen et al., 1995, Science. 268:1766-1769; Wang et al., 1994, Proc Natl Acad Sci USA 91:8180-8184), no single system is perfect at present. One potential drawback of these systems is leakage of transgene expression, causing limitations of each system. We have developed an inducible model containing both RU486 and CID systems, which in addition to inducing caspase activation, has potential applicability specifically to other genes encoding proteins that require a dimerization event for activation. This Double-Inducible Gene Activation System generates two barriers for the target gene expression and protein activation thereby minimizing leakage.     

Molecular cloning and functional expression of a sodium bicarbonate cotransporter from guinea-pig parotid glands

We recently found that the concentration of HCO3- in guinea-pig saliva is very similar to that of human saliva; however, the entity that regulates HCO3- transport has not yet been fully characterized. In order to investigate the mechanism of HCO3- transport, we identified, cloned, and characterized a sodium bicarbonate (Na(+)/HCO3- cotransporter found in guinea-pig parotid glands (gpNBC1). The gpNBC1 gene encodes a 1079-amino acid protein that has 95% and 96% homology with human and mouse parotid NBC1, respectively. Oocytes expressing gpNBC1 were exposed to HCO3- or Na(+)-free solutions, which resulted in a marked change in membrane potentials (V(m)), suggesting that gpNBC1 is electrogenic. Likewise, a gpNBC1-mediated pH recovery was observed in gpNBC1 transfected human hepatoma cells; however, in the presence of 4, 4-diisothiocyanostilbene-2,2-disulfonic acid, a specific NBC1 inhibitor, such changes in V(m) and pH(i) were not observed. Together, the data show that the cloned guinea-pig gene is a functional, as well as sequence homologue of human NBC1.