Neural control of the expression of a Ca2+-activated K+ channel involved in the induction of myotonic-like characteristics

Summary 1. Expression of the apamin-sensitive K⁺ channel (SK⁺) in rat skeletal muscle is neurally regulated. The regulatory effect of the nerve over the expression of some muscle ion channels has been attributed to the electrical activity triggered by the nerve and/or to a trophic effect of some molecules transported from the soma to the axonal endings. 2. SK⁺ channels apparently are involved in myotonic dystrophy (MD), therefore understanding the factors that regulate their expression may ultimately have important clinical relevance. 3. To establish if axoplasmic transport is involved in this process, we used two experimental approaches in adult rats: (a) Both sciatic nerves were severed, leaving a short or a long nerve stump attached to the anterior tibialis (AT). (b) Colchicine or vinblastine (VBL), two axonal transport blockers of different potencies, was applied on one leg to the sciatic nerve. To determine whether electrical activity affects the expression of SK⁺ channels, denervated AT were directly stimulated. The corresponding contralateral muscles were used as controls. 4. With these experimental conditions we measured (a) apamin binding to muscle membranes, (b) muscle contractile characteristics, and (c) electromyographic activity. 5. In the short- and long-nerve stump experiments, 5 days after denervation¹²⁵I-apamin binding to AT membranes was 2.0 times higher in the short-stump side. This difference disappeared at longer times. The delayed expression of SK⁺ channels in the muscle left with a longer nerve stump can be attributed to the extra axoplasm contained in the longer stump, which maintains a normally repressive signal for a longer period of time. Ten to 15 days after application of axonal transport blockers we found that the muscle half-relaxation time increased in the drug-treated side and apamin partially reverted the prolonged relaxation. Myotonic-like discharges specifically blockable by apamin were always present in the drug-treated leg.¹²⁵I-Apamin binding, which is undetectable in a microsomal preparation from hind leg control muscles, was increased in the drug-treated preparations. Apamin binding to denervated and stimulated AT muscles was lower than in the contralateral unstimulated muscles [3.3±1.0 vs 6.8±0.8 (n=4) fmol/mg protein]. 6. Our results demonstrate that electrical activity and axoplasmic transport are involved in the control of expression of SK⁺ in rat skeletal muscle. However, the increased expression of this channel induces myotonic-like characteristics that are reversed by apamin. This myotonic activity could be a model for MD.     

An increase of acidic isoform of catalase in red blood cells from HIV(+) population

A systemic oxidative stress of HIV (+) individuals has been recognized from a low glutathione level and a high level of inflammatory cytokines such as TNF. Previously, we demonstrated that the catalase enzyme activity in HIV (+) population is significantly altered depending on the cell types; the level was significantly high in red blood cells while the enzymes in white blood cells were remarkably low (Res Commun Subs Abuse 16: 161–176, 1995). In this study, we further characterized the difference in RBC catalase molecules between HIV (+) and control population. We have found that RBC from HIV (+) population, whether they were asymptomatic or symptomatic, contained a significantly elevated catalase protein accompanied by the enzyme activities, and that the majority of the elevated protein were acidic pl of the molecules with an identical subunit mass of approximately 60 KDa. These results suggest that catalase is induced prior to and/or during erythroid differentiation lineage in HIV (+) population as a somatic defense to respond and compensate for a systemic oxidative stress and for an anemic condition. (Mol Cell Biochem 165: 77–81, 1996)     

Markers for selection of the rice Xa21 disease resistance gene

Six molecular markers were mapped to a 7.4-cM region of rice chromosome 11 containing the Xa21 gene, which confers resistance to the pathogen Xanthomonas oryzae pv oryzae. Three markers, RG103, 248 and 818, co-segregated with Xa21 in a population of 1141 plants. Multiple copies of all marker loci were present within the region that was introgressed from Oryza longistaminata into O. sativa. The marker loci were cloned and primers were designed that defined sequence-tagged sites. Physical mapping of the three tightly linked central markers revealed that RG103, the marker that hybridizes to the Xa21 gene, resides on a separate DNA fragment from the other two markers.Disclaimer: Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Candida albicans stress mannoproteins expression in superficial and systemic candidiasis

The presence of heat shock mannoproteins (HSMPs) reactive with sIgA was demonstrated in several C. albicans strains. The subculture of the C. albicans isolated from mucosal surfaces on Sabouraud's dextrose agar at 25 °C switched off the HSMP expression. A re-expression of the HSMPs was obtained in the same medium by shifting the temperature of incubation to 37 °C. However, expression of HSMPs in two strains isolated from deep infections was maintained during several subcultures on Sabouraud's dextrose agar at 25 °C. A glycoprotein of 200 kDa seemed to be the main HSMP reacting with vaginal sIgA. The data presented in this study suggest that factors other than temperature can influence the expression of C. albicans HSMPs and therefore these antigens should be referred as stress mannoproteins.Abbreviations HSMPs heat shock mannoproteins - MAb monoclonal antibody - sIgA secretory IgA     

Polypores new to Japan 1. Species ofPolyporus,with a note onP. hartmanni

Polyporus admirabilis, P. dictyopus, P. guianensis, P. pseudobetulinus, P. tubaeformis andP. udus are reported for Japan for the first time.Polyporus tubaeformis had been confused withP. melanopus, but the Japanese collections were conspecific with Norwegian isolates ofP. tubaeformis. A key to allPolyporus species in Japan is provided.Polyporus hartmanni is reported for the first time outside the Australian continent. As the species has a bipolar heterothallism and produces brown rot, its taxonomic relationship withPolyporus s. str. is discussed.The Japanese Science and Technology Agency (STA) is thanked by the authors for financial support.     

The management of European estuaries: A comparison of the features,controls and management framework of the Tagus (Portugal) and Humber (England)

The paper describes the local, national, European and wider-area framework, statutes, and formal and voluntary mechanisms for managing European estuaries. These aspects are discussed in relation to two large and representative estuarine systems, the Tagus, Portugal, and the Humber, on the English North Sea coast As estuaries are sites of many activities and uses, most of which are encouraged or at least condoned, management has the role of preventing and resolving conflicts between those uses and users. Accepted uses of estuaries include the discharge and dumping of waste materials, fin and shell-fisheries, conservation, land reclamation, natural usage, abstraction by industry, and recreation. Estuarine management is now being carried out within the constraints of local and regional government planning, planning and activities of water pollution control bodies, fisheries control bodies, and navigation and port authorities The Tagus and Humber estuaries support all of the above activities and uses, and have controls within a European legislative framework but have differing histories of management and planning in order to resolve conflicts. In addition the Humber is subject to controls placed on North Sea areas. The paper discusses the relevant national and European legislation (Directives) and accepted practices for management. Furthermore, the paper discusses the formulation and practice of estuarine management plans as used by various bodies (nature conservation, water quality and regional authority). It is of particular note that the lessons from these two estuaries are relevant to many other European estuaries.     

Comparative biochemical studies of carotenoids in sea urchins—III. Relationship between developmental mode and carotenoids in the Australian echinoids Heliocidaris erythrogramma and H. tuberculata and a comparison with Japanese species

The sea urchin Heliocidaris tuberculata is typical of most echinoids in having a small egg and a feeding larva, while H. erythrogramma has a large egg and modified development through a non-feeding larvae. The carotenoids in the gonads of these two species were investigated from the comparative biochemical points of view. The carotenoid content of the buoyant eggs of H. erythrogramma was approximately 60 times that of the negatively-buoyant eggs of H. tuberculata. With respect to cytoplasmic volume, however, the carotenoid concentration in the eggs of H. tuberculata was approximately twice that in the eggs of H. erythrogramma. In both species β-echinenone was the principal carotenoid found and their carotenoid patterns were similar. It is very interesting from a functional point of view that carotenoid levels per cytoplasmic volume are conserved across most of the species we have examined irrespective of phylogeny and egg size. In light of this result we suggest that carotenoids may play an important role in developing stage in all echinoids including indirect and direct developers.     

Cloning and expression of the Neisseria meningitidis 5C outer membrane protein

The 5C outer membrane protein, one of the N. meningitidis class 5 proteins, was preferably expressed in bacteria isolated from the nasopharynx and its role in adhering to the mucosal cells and invading them as well as the development of anti-5C antibodies in healthy carriers was demonstrated. Anti-5C monoclonal antibodies are bactericidal in the presence of the human complement. The immunodominant region of the 5C protein is highly conserved among the different strains of N. meningitidis, and the opc gene, which encodes the protein, does not seem to show antigenic variations. Here the isolation of the opc gene from the Cuban strain B:4:P1.15 by PCR (Polymerase Chain Reaction) is presented. Under the regulation of the tryptophan promoter, the gene was cloned and sequenced in E. coli with a high level of expression and fused to the amino-terminal end of the interleukin-2 gene. In the dot-blot experiments, the presence of the gene in those strains which did not express the protein in the whole cell ELISA was also detectable.     

Diurnal rhythm of galanin-like immunoreactivity in the paraventricular and suprachiasmatic nuclei and other hypothalamic areas

The peptide galanin (GAL), when injected into the rat hypothalamus, is known to stimulate feeding behavior and affect the secretion of various hormones, including insulin and the adrenal steroid, corticosterone. To determine whether endogenous peptide levels shift in relation to natural rhythms of feeding and circulating hormone levels, rats were sacrificed at different times of the light/dark cycle, and their GAL levels were measured, via radioimmunoassay, in medial hypothalamic dissections and micropunched hypothalamic areas. The results suggest the existence of two distinct diurnal rhythms for hypothalamic GAL. One rhythm, detected exclusively in the area of the SCN, is characterized by bimodal peaks of GAL, threefold higher than basal peptide levels, around the onset of the dark and light periods. The second rhythm shows a single peak of GAL towards the middle of the nocturnal feeding cycle, specifically between the third and sixth hour. This latter rhythm is evident in the dorsal region of the medial hypothalamus, localized specifically to the lateral portion of the PVN. Moreover, it is inversely related to circulating insulin but unrelated to the adrenal steroids, suggesting a possible association between this pancreatic hormone and GAL in the PVN.