Polymerase chain reaction-based snake origin tracing in commercial venom crystals by targeting the mitochondrial D-loop.

Snake venom is a valuable raw material for numerous therapeutic formulations because of its life-saving pharmacological potential. However, due to their high price, fake "snake venoms" have captured a significant portion of the global market, and there is currently no reliable reported DNA-based method available for quickly distinguishing between fakes and originals. Therefore, in this study, a set of newly designed snake-specific universal primers targeting mitochondrial D-loop fragments were employed to detect snake origins in commercial venom crystals by only simplex polymerase chain reaction analysis. Under the optimal thermal cycling conditions, only the 145-149 bp snake-specific mitochondrial D-loop fragments from pure and mixed backgrounds were amplified by the newly designed primers. Specificity was achieved by confirming no DNA amplification occurred in the DNA admixture of ten different chordates, and universality by individual DNA amplification of nine different snakes. The primers that efficiently amplified the minimum mitochondrial DNA contained in a total of 10-2 ng in a 10.0 µl reaction were also successfully able to detect the snake origin in commercial cobra venom crystals. These findings suggest that the newly designed primers can be used to differentiate the original and fake commercial snake venom crystals in order to achieve the highest standards of snake venom-based medications through amplifying the snake-specific mitochondrial D-loop fragments.

Virtual screening, molecular dynamics, density functional theory and quantitative structure activity relationship studies to design peroxisome proliferator-activated receptor-γ agonists as anti-diabetic drugs.

Type 2 diabetes (T2D) is generally characterized by elevated blood glucose levels, insulin resistance, and relative lack of insulin; however, insulin resistance is the predominant risk factor. Hence, the use of insulin sensitizer drugs to increase insulin sensitivity has gained immense interest as an attractive treatment option for T2D and their major target is a nuclear receptor PPAR-γ (peroxisome proliferator-activated receptor-γ). A wide range of synthetic insulin sensitizers such as thiazolidinedione act as PPAR-γ agonists thereby enhancing insulin action and improving hyperglycemia in patients. Nonetheless, they pose severe adverse effects for human, necessitating an emergent need to develop effective insulin sensitizer drugs. Herein, virtual screening of 10,000 ligands is performed and the best five ligands are identified. MET364, ILE341, CYS285, ALA292, PHE282, and LEU330 residues are found to play an important role in ligand binding. It is shown from the molecular dynamics simulations results of the top-ranked ligands that increased numbers of hydrogen bonds are formed with PPAR-γ catalytic residues. Quantum chemical calculations reveal that all the best ligands can demonstrate good thermodynamic stability and pharmacokinetic properties. Partial-least-square (PLS) regression of quantitative structural activity relationship (QSAR) is utilized to model and predict the binding energy for ligands. Principal component analysis is further explored for the best ligands' QSAR pattern recognition. Importantly, the predicted values of the binding energy of the potential ligands by the PLS regression is favourably compared with the values of binding energy obtained from molecular docking with incredible high accuracy of 98%.

Antiviral Peptides as Promising Therapeutics against SARS-CoV-2.

Over 50 peptides, which were known to inhibit SARS-CoV-1, were computationally screened against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. Based on the binding affinity and interaction, 15 peptides were selected, which showed higher affinity compared to the α-helix of the human ACE2 receptor. Molecular dynamics simulation demonstrated that two peptides, S2P25 and S2P26, were the most promising candidates, which could potentially block the entry of SARS-CoV-2. Tyr489 and Tyr505 residues present in the "finger-like" projections of the RBD were found to be critical for peptide interaction. Hydrogen bonding and hydrophobic interactions played important roles in prompting peptide-protein binding and interaction. Structure-activity relationship indicated that peptides containing aromatic (Tyr and Phe), nonpolar (Pro, Gly, Leu, and Ala), and polar (Asn, Gln, and Cys) residues were the most significant contributors. These findings can facilitate the rational design of selective peptide inhibitors targeting the spike protein of SARS-CoV-2.

Multimorbidity predicts falls differentially according to the type of fall in postmenopausal women.

OBJECTIVE: To ascertain whether the risk of falls of different types is related to morbidity (number of chronic medical conditions) among postmenopausal women. STUDY DESIGN: This cohort study uses data from a population-based prospective cohort study (OSTPRE). The study population consisted of 10,594 women aged 47-56 years living in Kuopio Province, Eastern Finland, in 1989, who responded to postal enquiries at both baseline and 5-year follow-up, in 1994. Morbidity (i.e. number of diagnosed chronic medical conditions) was reported in 1989 and falls in 1994. Falls were categorized as slip or nonslip, and 'frequent falls' was defined as two or more in a 12-month period. RESULTS: The risk (odds ratio (OR) with 95% CI) of a fall increased with the number of chronic medical conditions. The OR was 1.28 (1.17-1.40) for those with 1-2 conditions and 1.41 (1.24-1.60) for those with multimorbidity (≥3 conditions) compared with healthy respondents. Multimorbidity was associated with a greater risk of the woman experiencing frequent nonslip falls (OR=2.57; 2.01-3.29) than frequent slip falls (OR=1.46; 1.17-1.80). Adjusting with logistic regression for age, number of medications and smoking did not affect the risk estimates. CONCLUSION: Multimorbidity has a much smaller effect on slip than on nonslip falls in postmenopausal women. This should be taken into account when investigating the effects of multimorbidity on fall risk in varying weather conditions.