Characterization of a cloned cDNA encoding rabbit myelin P2 protein

Myelin P2 is a 14,800-Da cytosolic protein found in rabbit sciatic nerves. It belongs to a family of fatty acid binding proteins and shows a 72% amino acid sequence similarity to aP2/422, the adipocyte lipid binding protein, a 58% sequence similarity to rat heart fatty acid binding protein, and a 40% sequence similarity to cellular retinoic acid binding protein. In order to isolate cDNA clones representing P2, a cDNA library was constructed from poly(A+) RNA isolated from sciatic nerves of 10-day-old rabbit pups. By use of a mixed synthetic oligonucleotide probe based on the rabbit P2 amino sequence, 12 cDNA clones were selected from about 25,000 recombinants. Four of these were further characterized. They contained an open reading frame, which when translated, agreed at 128 out of 131 residues with the known rabbit P2 amino acid sequence. These cDNAs recognize a 1.9-kilobase mRNA present in sciatic nerve, spinal cord, and brain, but not present in liver or heart. The levels of P2 mRNA parallel myelin formation in sciatic nerve and spinal cord with maximal amounts being detected at about 15 postnatal days. This initial study will allow characterization of the P2 gene and its regulation, as well as further studies into the role of P2, the first metabolically active myelin-specific protein to be characterized at the genetic level.     

Collagen synthesis by human fibroblasts. Regulation by transforming growth factor-beta in the presence of other inflammatory mediators.

C1r2C1s2 is a subcomponent of first component C1 of the complement cascade. Previously two distinct models for its structure have been described, in which C1r2C1s2 is either a linear rod-like assembly of the globular domains found in each of C1s and C1r, or these domains are arranged to form an asymmetric X-shaped structure. These two models were evaluated by using hydrodynamic simulations and neutron scattering. The data on C1s, C1s2 and C1r are readily represented by straight hydrodynamic cylinders, but not C1r2 or C1r2C1s2. Tests of the X-structure for C1r2 and C1r2C1s2 successfully predicted the experimental sedimentation coefficients, thus supporting this model. Neutron scattering analyses on C1s and C1r2 are consistent with a linear structure for C1s, but not for C1r2. An X-shaped structure for C1r2 was found to give a good account of the neutron data at large scattering angles. The total length of the C1s and C1r monomers was determined as 17-20 nm, which is compatible with electron microscopy. On the basis of the known sequences of C1r and C1s, this length is accounted for by a linear arrangement of a serine-proteinase domain (length 4 nm), two short consensus repeat domains (2 x 4 nm), and a globular entity containing the I, II and III domains (4-7 nm).     

Influence of phospholipase C on muscarinic acetylcholine receptor binding in rat brain

Treatment of neural membranes from rat cerebral cortex with phospholipase C (phosphatidylcholine cholinephosphohydrolase) inhibited the binding of radiolabelled antagonists to muscarinic acetylcholine receptors. This inhibition was incomplete, was not competitive, and did not appear to be related to the production of inhibitory products. The affinity of carbamylcholine for cortex muscarinic receptors was increased by phospholipase C action. The distribution of receptors between states of high and low affinity was not affected by phospholipase C; rather, the affinity for carbamylcholine of the lowest affinity receptors was selectively increased. This suggests that membrane lipids influence the interaction of the receptor binding subunit with other structures in the synaptic membrane.     

Effect of xiphidiocercarial infection on oxidation of glycolytic and Krebs cycle intermediates in Lymnaea luteola (Mollusca)

With the aim of assessing the effect of xiphidiocercarial infection on its gastropod host, Lymnaea luteola, the oxidation of glycolytic and tricarboxylic acid cycle intermediates by digestive gland homogenates of uninfected and infected snails was studied manometrically. The oxidation of glycolytic and NAD-linked substrates was reduced in infected snails. On the other hand, succinate oxidation was very high in infected snails and the reasons for this are discussed.     

Identification and characterization of Neopestalotiopsis clavispora associated with leaf blight of small cardamom (Elettaria cardamomum Maton)

Leaf blight is a major foliar disease prevalent in all cardamom‐cultivating tracts, manifesting in diverse forms of symptoms. In this study, six symptomatological variants were delineated based on the expression of foliar symptoms in cardamom genotypes (Malabar, Mysore and Vazhukka) and designated as SV 1 to SV 6. Among the symptomatological variants, SV 1, SV 2, SV 3 and SV 6 were more pronounced in Vazhukka, while SV 4 and SV 5 were prominent in Malabar type. Subsequent isolation from the variants yielded whitish colonies, which were correspondingly coded as SV 1 to SV 6. The conidia were fusiform, five‐celled, with three median versicoloured cells, two terminal hyaline cells and measured 23.1–27.25 × 3.84–4.43 μm. The apical cells had two to three tubular, flexuous, unbranched appendages, whereas the basal appendage was single, tubular and unbranched. Based on conidial characteristics and molecular characterization with internal transcribed spacer rDNA region, partial β‐tubulin, translation elongation factor 1 alpha and large subunit (28S) of the nrRNA genes revealed identity of the pathogens as Neopestalotiopsis clavispora. The pathogenicity test was performed on Malabar, Mysore and Vazhukka genotypes, and Koch’s postulates were proved. In‐vitro interaction at three temperature regimes indicated that N. clavispora was inhibitory to Colletotrichum gloeosporioides at 10 and 30°C. Among the fungicides, carbendazim, propiconazole and carbendazim‐mancozeb completely arrested hyphal growth of N. clavispora under in‐vitro conditions. This study constitutes first report on the association of Neopestalotiopsis clavispora with leaf blight disease of small cardamom.