Characterization of the interaction of influenza virus NS1 with Akt

Avian influenza viruses belong to the genus influenza A virus of the family Orthomyxoviridae. The influenza virus consists of eight segmented minus stranded RNA that encode 11 known proteins. Among the 11 viral proteins, NS1 (non-structural protein 1, encoded on segment 8) has been implicated in the regulation of several important intra-cellular functions.In this report, we investigated the functional interaction of NS1 with serine threonine kinase Akt, a core intra-cellular survival regulator. In co-immunoprecipitation assays and GST pull-down assays, NS1 directly interacted with Akt. The interaction was mediated primarily through the Akt-PH (Pleckstrin Homology) domain and the RNA-binding domain of NS1. NS1 preferentially interacted with phosphorylated Akt, but not with non-phosphorylated Akt. Functionally, the NS1-Akt interaction enhanced Akt activity both in the intra-cellular context and in in vitro Akt kinase assays. Confocal microscopic analysis revealed that phosphorylated Akt interacted with NS1 during the interphase of the cell cycle predominantly within the nucleus. Finally, mass spectrometric analysis demonstrated the position at Thr215 of NS1 protein is primary phosphorylation target site through Akt activation. The results together supported the functional importance of influenza virus NS1 with Akt, a core intra-cellular survival regulator.     

Fatty acid derivatives and dammarane triterpenes from the glandular trichome exudates of Ibicella lutea and Proboscidea louisiana

Ibicella lutea and Proboscidea louisiana, both of the Martyniaceae family, are known for rich glandular trichomes on their leaves and stems. Chemical investigations of the glandular trichome exudates on leaves of the two plants furnished three types of secondary metabolites, glycosylated fatty acids, glycerides (2-O-(3,6-diacetyloxyfattyacyl)glycerols and 2-O-(3-acetyloxyfattyacyl)glycerols) and dammarane triterpenes. The glycosylated fatty acids from I. lutea were determined to be 6(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-octadecanoic acid (1A), -eicosanoic acid (1B) and -docosanoic acid (1C), as well as their respective deacetyl congeners (2A, 2B and 2C), whereas P. louisiana furnished 8(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-eicosanoic acid (3A) and -docosanoic acid (3B) and their respective deacetyl congeners (4A and 4B), together with 2B. Both plants contained 12 identical 2-O-[(3R,6S)-3,6-diacetyloxyfattyacyl]glycerols (5A-L), in which the fatty acyl moieties contained between 17 and 21 carbon atoms. The corresponding mono-acetyloxy compounds, 2-O-[(3R)-3-acetyloxyfattyacyl]glycerols (6A–L) were detected in both plants. Among these glycerides, ten compounds (5A, 5C, 5F, 5H, 5K, 6A, 6C, 6F, 6H and 6K) had iso-fattyacyl structures and four (5E, 5J, 6E and 6J) had anteiso-fattyacyl structures. A previously unknown dammarane triterpene, betulatriterpene C 3-acetate (7), was isolated together with three known dammarane triterpenes, 24-epi-polacandrin 1,3-diacetate (8), betulatriterpene C (9) and 24-epi-polacandrin 3-acetate (10) from I. lutea, whereas 12 dammarane triterpenes, named probosciderols A–L (12–23), and the known compound betulafolienetriol (11) were isolated from P. louisiana. The structures of these compounds were elucidated by spectroscopic analysis including 2D-NMR techniques and chemical transformations. The 6-O-acetylglucosyloxy-fatty acids 1A–C (42%) and the dammarane triterpenes 7–10 (31%) were the two most abundant constituents in the glandular trichome exudate of I. lutea, whereas the dammarane triterpenes 11–23 (47%) and the glucosyloxy-fatty acids (4A, 4B and 2B) (38%) were the most abundant constituents in the glandular trichome exudate of P. louisiana.     

Silicon enhances growth independent of silica deposition in a low-silica rice mutant, lsi1

To examine whether silica bodies are essential for silicon-enhanced growth of rice seedlings, we investigated the response of rice, Oryza sativa L., to silicon treatment. Silicic acid treatment markedly enhanced the SPAD (soil plant analytical development) values of leaf blades and the growth and development of leaves and lateral roots in cvs. Hinohikari and Oochikara, and a low-silicon mutant, lsi1. Combination of ethanol–benzene displacement and staining with crystal violet lactone enabled more detailed histochemical analysis to visualize silica bodies in the epidermis under bright-field microscopy. Supply of silicon induced the development of motor cells and silica bodies in epidermal cells in Hinohikari and Oochikara but not or marginal in lsi1. X-ray analytical microscopy detected silicon specifically in the leaf sheath, the outermost part of the stem, and the leaf blade midrib, suggesting that silicon is distributed to tissues involved in maintaining rigidity of the plant to prevent lodging, rather than being passively deposited in growing tissues. Silicon supplied at high dose accumulated in all rice seedlings and enhanced growth and SPAD values with or without silica body formation. Silicon accumulated in the cell wall may play an important physiological role different from that played by the silica deposited in the motor cell and silica bodies.     

Enhanced angiogenic potency of monocytic endothelial progenitor cells in patients with systemic sclerosis

Introduction  

Microvasculopathy is one of the characteristic features in patients with systemic sclerosis (SSc), but underlying mechanisms still remain uncertain. In this study, we evaluated the potential involvement of monocytic endothelial progenitor cells (EPCs) in pathogenic processes of SSc vasculopathy, by determining their number and contribution to blood vessel formation through angiogenesis and vasculogenesis.     

Experimental eradication of pinworms (Syphacia obvelata and Aspiculuris tetraptera) from mice colonies using ivermectin.

A spray administration of ivermectin was evaluated for the treatment of pinworm infection in mice. In this study, a spray of 0.1% ivermectin injectable solution over the entire cage once a week, for three consecutive weeks (one cycle treatment), was effective in eradicating both Syphacia obvelata and Aspiculuris tetraptera from mice under experimental conditions. In addition, no acute toxicity was observed in 105 mothers or 687 neonates treated with ivermectin, indicating that ivermectin does not affect murine reproduction. Finally, we attempted to eradicate pinworms from infected mice in our institute using this method. Two cycles of treatment were administered, with a two-week pause between cycles, resulting in complete eradication for at least one year. Treating mouse colonies with spray ivermectin is inexpensive, safe, requires very little labor and is very effective at eradicating pinworms from mice.     

SCRAPPER-dependent ubiquitination of active zone protein RIM1 regulates synaptic vesicle release

Little is known about how synaptic activity is modulated in the central nervous system. We have identified SCRAPPER, a synapse-localized E3 ubiquitin ligase, which regulates neural transmission. SCRAPPER directly binds and ubiquitinates RIM1, a modulator of presynaptic plasticity. In neurons from Scrapper-knockout (SCR-KO) mice, RIM1 had a longer half-life with significant reduction in ubiquitination, indicating that SCRAPPER is the predominant ubiquitin ligase that mediates RIM1 degradation. As anticipated in a RIM1 degradation defect mutant, SCR-KO mice displayed altered electrophysiological synaptic activity, i.e., increased frequency of miniature excitatory postsynaptic currents. This phenotype of SCR-KO mice was phenocopied by RIM1 overexpression and could be rescued by re-expression of SCRAPPER or knockdown of RIM1. The acute effects of proteasome inhibitors, such as upregulation of RIM1 and the release probability, were blocked by the impairment of SCRAPPER. Thus, SCRAPPER has an essential function in regulating proteasome-mediated degradation of RIM1 required for synaptic tuning.     

Persistence of caliciviruses in artificially contaminated oysters during depuration

The fate of calicivirus in oysters in a 10-day depuration was assessed. The norovirus gene was persistently detected from artificially contaminated oysters during the depuration, whereas feline calicivirus in oysters was promptly eliminated. The prolonged observation of norovirus in oysters implies the existence of a selective retention mechanism for norovirus within oysters.     

An asparaginyl endopeptidase mediates in vivo protein backbone cyclization

Proteases can catalyze both peptide bond cleavage and formation, yet the hydrolysis reaction dominates in nature. This presents an interesting challenge for the biosynthesis of backbone cyclized (circular) proteins, which are encoded as part of precursor proteins and require post-translational peptide bond formation to reach their mature form. The largest family of circular proteins are the plant-produced cyclotides; extremely stable proteins with applications as bioengineering scaffolds. Little is known about the mechanism by which they are cyclized in vivo but a highly conserved Asn (occasionally Asp) residue at the C terminus of the cyclotide domain suggests that an enzyme with specificity for Asn (asparaginyl endopeptidase; AEP) is involved in the process. Nicotiana benthamiana does not endogenously produce circular proteins but when cDNA encoding the precursor of the cyclotide kalata B1 was transiently expressed in the plants they produced the cyclotide, together with linear forms not commonly observed in cyclotide-containing plants. Observation of these species over time showed that in vivo asparaginyl bond hydrolysis is necessary for cyclization. When AEP activity was suppressed, either by decreasing AEP gene expression or using a specific inhibitor, the amount of cyclic cyclotide in the plants was reduced compared with controls and was accompanied by the accumulation of extended linear species. These results suggest that an AEP is responsible for catalyzing both peptide bond cleavage and ligation of cyclotides in a single processing event.