Biochemical characterization of C4 protein of cotton leaf curl Kokhran virus-Dabawali

Background: Cotton leaf curl Kokhran Virus-Dabawali (CLCuKV-Dab) is a monopartite begomovirus encoding two proteins V1 and V2 in the virion sense and four proteins Cl, C2, C3 and C4 in the complementary sense. The C4 protein of monopartite begomoviruses has been implicated to play a role in symptom determination and virus movement. The present work aims at the biochemical characterization of this protein. Methods: The C4 protein of CLCuKV-Dab was purified in fusion with GST and tested for the ability to hydrolyze ATP and other phosphate containing compounds. ATPase activity was assayed by using radiolabeled gamma-32P]-ATP and separating the product of reaction by thin layer chromatography. The hydrolysis of other compounds was monitored by the formation of a blue colored phosphomolybdate complex which was estimated by measuring the absorbance at 655 nm. Results: The purified GST-C4 protein exhibited metal ion dependent ATPase and inorganic pyrophosphatase activities. Deletion of a sequence resembling the catalytic motif present in phosphotyrosine phosphatases resulted in 70% reduction in both the activities. Mutational analysis suggested arginine 13 to be catalytically important for the ATPase and cysteine 8 for the pyrophosphatase activity of GST-C4. Interaction of V2 with GST-C4 resulted in an increase in both the enzymatic activities of GST-C4. Conclusions: The residues important for the enzymatic activities of GST-C4 are present in a motif different from the classical Walker motifs and the non-classical ATP binding motifs reported so far. General significance: The C4 protein of CLCuKV-Dab, a putative natively unfolded protein, exhibits enzymatic activities.

Establishment, characterization, and virus susceptibility of a new marine cell line from red spotted grouper (Epinephelus akaara)

A marine fish cell line from the snout of red spotted grouper Epinephelus akaara, a protogynous hermaphrodite, was established, characterized, and subcultured with more than 60 passages. The grouper snout cell line (GSC) cells multiplied well in Dulbecco's modified Eagle's medium (DMEM) medium supplemented with 10% fetal bovine serum. The optimal growth temperature was 25 degrees C, and morphologically the cells were fibroblastic. Chromosome analysis revealed that the GSC cell line has a normal diploid karyotype with 2n = 8st + 40t. A virus titration study indicated that the cells were susceptible to turbot Scophthalmus Maximus rhabdovirus (SMRV) (10(8.5) TCID50 ml(-1)), while the viral titer of frog Rana grylio virus 9807 (RGV(9807)) reached 10(3.5) TCID50 ml-1. The infection was confirmed by cytopathic effect (CPE), immunofluorescence, and electron microscopy experiments, which detected the viral particles in the cytoplasm of virus-infected cells, respectively. Further, significant fluorescent signals were observed when the GSC cells were transfected with pEGFP vector DNA, indicating their potential utility for transgenic and genetic manipulation studies.

Novel dermaseptin, adenoregulin and caerin homologs from the Central American red-eyed leaf frog, Agalychnis callidryas, revealed by functional peptidomics of defensive skin secretion

By integrating systematic peptidome and transcriptome studies of the defensive skin secretion of the Central American red-eyed leaf frog, Agalychnis callidryas, we have identified novel members of three previously described antimicrobial peptide families, a 27-mer dermaseptin-related peptide (designated DRP-AC4), a 33-mer adenoregulin-related peptide (designated ARP-AC1) and most unusually, a 27-mer caerin-related peptide (designated CRP-AC1). While dermaseptin and adenoregulin were originally isolated from phyllomedusine leaf frogs, the caerins, until now. had only been described in Australian frogs of the genus, Litoria. Both the dermaseptin and adenoregulin were C-terminally amidated and lacked the C-terminal tripeptide of the biosynthetic precursor sequence. In contrast, the caerin-related peptide, unlike the majority of Litoria analogs. was not C-terminally amidated. The present data emphasize the need for structural characterization of mature peptides to ensure that unexpected precursor cleavages and/or post-translational modifications do not produce mature peptides that differ in structure to those predicted from cloned biosynthetic precursor cDNA. Additionally, systematic study of the secretory peptidome can produce unexpected results such as the CRP described here that may have phylogenetic implications. It is thus of the utmost importance in the functional evaluation of novel peptides that the primary structure of the mature peptide is unequivocally established - something that is often facilitated by cloning biosynthetic precursor cDNAs but obviously not reliable using such data alone. (C) 2008 Elsevier Masson SAS. All rights reserved.

Effect of red clover-derived isoflavone supplementation on insulin-like growth factor, lipid and antioxidant status in healthy female volunteers: a pilot study

Background: Isoflavones are estrogen-like plant compounds that may protect against cardiovascular disease and endocrine-responsive cancer. Isoflavones may, because of their ability to act as selective estrogen receptor modulators, alter insulin-like growth factor (IGF) status.

A novel Kazal-type trypsin inhibitor from the skin secretion of the Central American red-eyed leaf frog, Agalychnis callidryas.

The chemical complexity of the defensive skin secretion of the red-eyed leaf frog, (Agalychnis callidryas), has not been elucidated in detail. During a systematic study of the skin secretion peptidomes of phyllomedusine frogs, we discovered a novel Kazal-type protein with potent trypsin inhibitory activity (Ki = 1.9 nM) that displays the highest degree of structural similarity with Kazal proteins from bony fishes. The protein was located in reverse-phase HPLC fractions following a screen of such for trypsin inhibition and subsequent partial Edman degradation of the peak active fraction derived the sequence: ATKPR-QYIVL-PRILRPV-GT. The molecular mass of the major component in this fraction was established by MALDI-TOF MS as 5893.09 Da. This partial sequence (assuming blank cycles to be Cys residues) was used to design a degenerate primer pool that was employed successfully in RACE-PCR to clone homologous precursor-encoding cDNA that encoded a mature Kazal protein of 52 amino acid residues with a computed molecular mass of 5892.82 Da. The protein was named A. callidryas Kazal trypsin inhibitor (ACKTI). BLAST analysis revealed that ACKTI contained a canonical Kazal motif (C-x(7)-C-x(6)-Y-x(3)-C-x(2,3)-C). This novel amphibian skin Kazal trypsin inhibitor adds to the spectrum of trypsin inhibitors of Kunitz- and Bowman Birk-type reported from this amphibian source.

Recombinant canine distemper virus strain Snyder Hill expressing green or red fluorescent proteins causes meningoencephalitis in the ferret

The propensity of canine distemper virus (CDV) to spread to the central nervous system is one of the primary features of distemper. Therefore, we developed a reverse genetics system based on the neurovirulent Snyder Hill (SH) strain of CDV (CDV(SH)) and show that this virus rapidly circumvents the blood-brain and blood-cerebrospinal fluid (CSF) barriers to spread into the subarachnoid space to induce dramatic viral meningoencephalitis. The use of recombinant CDV(SH) (rCDV(SH)) expressing enhanced green fluorescent protein (EGFP) or red fluorescent protein (dTomato) facilitated the sensitive pathological assessment of routes of virus spread in vivo. Infection of ferrets with these viruses led to the full spectrum of clinical signs typically associated with distemper in dogs during a rapid, fatal disease course of approximately 2 weeks. Comparison with the ferret-adapted CDV(5804P) and the prototypic wild-type CDV(R252) showed that hematogenous infection of the choroid plexus is not a significant route of virus spread into the CSF. Instead, viral spread into the subarachnoid space in rCDV(SH)-infected animals was triggered by infection of vascular endothelial cells and the hematogenous spread of virus-infected leukocytes from meningeal blood vessels into the subarachnoid space. This resulted in widespread infection of cells of the pia and arachnoid mater of the leptomeninges over large areas of the cerebral hemispheres. The ability to sensitively assess the in vivo spread of a neurovirulent strain of CDV provides a novel model system to study the mechanisms of virus spread into the CSF and the pathogenesis of acute viral meningitis.

AcT-2: A Novel Myotropic and Antimicrobial Type 2 Tryptophyllin from the Skin Secretion of the Central American Red-Eyed Leaf Frog, Agalychnis callidryas

Tryptophyllins are a diverse family of amphibian peptides originally found in extracts of phyllomedusine frog skin by chemical means. Their biological activities remain obscure. Here we describe the isolation and preliminary pharmacological characterization of a novel type 2 tryptophyllin, named AcT-2, from the skin secretion of the red-eyed leaf frog, Agalychnis callidryas. The peptide was initially identified during smooth muscle pharmacological screening of skin secretion HPLC fractions and the unique primary structure—GMRPPWF-NH2—was established by both Edman degradation and electrospray MS/MS fragmentation sequencing. A. cDNA encoding the biosynthetic precursor of AcT-2 was successfully cloned from a skin secretion-derived cDNA library by means of RACE PCR and this contained an open-reading frame consisting of 62 amino acid residues with a single AcT-2 encoding sequence located towards the C-terminus. A synthetic replicate of AcT-2 was found to relax arterial smooth muscle (EC50 = 5.1 nM) and to contract rat urinary bladder smooth muscle (EC50 = 9.3 μM). The peptide could also inhibit the growth of the microorganisms, Staphylococcus aureus, (MIC = 256 mg/L) Escherichia coli (MIC = 512 mg/L), and Candida albicans (128 mg/L). AcT-2 is thus the first amphibian skin tryptophyllin found to possess both myotropic and antimicrobial activities.

Identification and Functional Analysis of a Novel Tryptophyllin Peptide from the Skin of the Red-eye Leaf Frog, Agalychnis callidryas

Amphibian skin has proved repeatedly to be a largely untapped source of bioactive peptides and this is especially true of members of the Phyllomedusinae subfamily of frogs native to South and Central America. Tryptophyllins are a group of peptides mainly found in the skin of members of this genus. In this study, a novel tryptophyllin (TPH) type 3 peptide, named AcT-3, has been isolated and structurally-characterised from the skin secretion and lyophilised skin extract of the red-eye leaf frog, Agalychnis callidryas. The peptide was identified in and purified from the skin secretion by reverse-phase HPLC. MALDI-TOF mass spectrometry and MS/MS fragmentation sequencing established its primary structure as: pGlu-Gly-Lys-Pro-Tyr-Trp-Pro-Pro-Pro-Phe-Leu-Pro-Glu, with a non-protonated molecular mass of 1538.19Da. The mature peptide possessed the canonical N-terminal pGlu residue that arises from post-translational modification of a Gln residue. The deduced open-reading frame consisted of 63 amino acid residues encoding a highly-conserved signal peptide of approximately 22 amino acid residues, an intervening acidic spacer peptide domain, a single AcT-3 encoding domain and a C terminal processing site. A synthetic replicate of AcT-3 was found to antagonise the effect of BK on rat tail artery smooth muscle and to contract the intestinal smooth muscle preparations. It was also found that AcT-3 could dose-dependently inhibit the proliferation of human prostate cancer cell lines after 72h incubation.

Squirrelpox virus in Northern Ireland: quantifying the risk to red squirrels.

Information and collated statistical analysis on the decline of red squirrels.