The effect of the glycolipoprotein extract (G-90) from earthworm Eisenia foetida on the wound healing process in alloxan-induced diabetic rats.

Diabetes is now regarded as a major public health problem. The number of patients is estimated to increase to over 439 million cases by 2030. One of the major health clinical problems in patients with diabetes patients is impaired wound healing. Diabetic foot ulcer is a major complication of diabetes mellitus in 12 to 25% of patients, which increases the risk of damage in the limbs or amputation. The earthworm Eisenia foetida glycolipoprotein (as known G-90) is a blend of macromolecules with some biological properties including mitogenicity, anticoagulation, fibrinolysis, bacteriostatic and antioxidatiaon. Given the biological properties of G-90, this study was conducted to investigate the effect of extract obtained from the homogenate of Eisenia foetida (G-90) on the wound healing process in alloxan-induced diabetic rats. The results of the present study revealed that treatment by using G-90 can speed up the wound healing process, which is exactly similar to the effect of D-panthenol treatment in rats. These findings also demonstrated that G-90 treatment decreases the risk of infection in the wound site compared with D-panthenol treatment. In addition, histological analysis indicated that a better extracellular matrix formation with increased fibroblast proliferation, neovascularization, collagen synthesis and early epithelial layer formation was observed in G-90 treated group. Therefore, the G-90 could be considered as a new wound healing agent introducing promising therapeutic approaches in both human and veterinary medicine. Copyright © 2016 John Wiley & Sons, Ltd.

Structural and functional characterization of a mutant of Pseudocerastes persicus natriuretic peptide.

We hereby report on a mutational analysis of a novel natriuretic peptide (PNP), recently isolated by us from the Iranian snake venom. The PNP variant (mutPNP) with four substitutions (G16T, K18S, R21S, G23R) and a disulfide bonded ring shortened by 3 residues. mutPNP peptide was expressed in pET32 and purified by affinity separation on nickel resin followed by RP-HPLC chromatography. The conformation of mutPNP was characterized in solution by 1H nuclear magnetic resonance spectroscopy, where it was found that the 14-residue disulfide bonded ring, like the 17-residue ring in PNP, retains a high degree of conformational flexibility. The conformation of mutPNP bound to NPR-C receptor was predicted by homology protein structure modeling. When injected intravenously into rats, mutPNP, in contrast to PNP had no physiological effect on blood pressure or on diuresis. The loss of physiological activity is explained in terms of the modeled bound conformation and the ensemble of solution conformations obtained using the NMR constraints.

Solution structure of long neurotoxin NTX-1 from the venom of Naja naja oxiana by 2D-NMR spectroscopy.

The NMR solution structures of NTX-1 (PDB code 1W6B and BMRB 6288), a long neurotoxin isolated from the venom of Naja naja oxiana, and the molecular dynamics simulation of these structures are reported. Calculations are based on 1114 NOEs, 19 hydrogen bonds, 19 dihedral angle restraints and secondary chemical shifts derived from 1H to 13C HSQC spectrum. Similar to other long neurotoxins, the three-finger like structure shows a double and a triple stranded beta-sheet as well as some flexible regions, particularly at the tip of loop II and the C-terminal tail. The solution NMR and molecular dynamics simulated structures are in good agreement with root mean square deviation values of 0.23 and 1 A for residues involved in beta-sheet regions, respectively. The overall fold in the NMR structure is similar to that of the X-ray crystallography, although some differences exist in loop I and the tip of loop II. The most functionally important residues are located at the tip of loop II and it appears that the mobility and the local structure in this region modulate the binding of NTX-1 and other long neurotoxins to the nicotinic acetylcholine receptor.

Functional and structural characterization of a novel member of the natriuretic family of peptides from the venom of Pseudocerastes persicus.

A novel peptide, PNP (Pseudocerastes persicus natriuretic peptide), was isolated from the venom of the Iranian viper P. persicus. Amino acid sequencing revealed that the 37-residue peptide belongs to the family of natriuretic peptides. The physiological effects of intra-venously PNP infused into anesthetized rats on urine flow, sodium excretion and blood pressure were comparable to those of atrial natriuretic peptide (ANP). In PC12 cells that were treated with either PNP, ANP, or C-type natriuretic peptide, PNP induced a similar cGMP response as ANP. Since PC12 cells only express the natriuretic peptide receptor (NPR)-A receptor we conclude that PNP binds to the NPR-A receptor. The solution conformation of PNP was characterized using (1)H nuclear magnetic resonance spectroscopy and indicates a high degree of conformational flexibility.