Yanbian University

The tiger population in Southwest Primorye is small and predominantly isolated from the main Sikhote-Alin population, which constitutes approximately 90% of the wild Amur tiger population. By 1996, this population declined to fewer than 10 individuals, but it has since grown and expanded into nearby habitats, now numbering over 50 individuals. Therefore, the regular genetic monitoring of this population is essential, as it has grown from a few founding members and remained geographically isolated.

Genetic diversity was assessed using nine heterologous microsatellite markers amplified from non-invasively collected samples of 20 individual tigers. The Southwest Primorye tiger population exhibited moderate genetic diversity, with allelic richness (Na) at 3.67 and observed heterozygosity (Ho) at 0.63. Additionally, we detected a slight tendency toward heterozygosity excess at several loci, with an overall negative FIS, which may be influenced by recent genetic admixture or subtle population structuring. comparative assessment between our study and Sugimoto et al. (2012) revealed a marginal increase in genetic diversity over time, suggesting improved genetic health of the population, potentially due to genetic exchange with other populations.

The significant growth and expansion of the Southwest Primorye tiger population into adjacent areas of Northeast China over the past two decades suggest a positive population trajectory. This modest increase in genetic diversity indicates a potentially favorable population condition. However, continuous genetic monitoring remains essential to track genetic trends, detect potential risks, and inform conservation strategies. This study highlights the need for ongoing evaluations to ensure the long-term survival of the Amur tiger population in Southwest Primorye.

Diabetes mellitus necessitates strict control of postprandial hyperglycemia via α-glucosidase inhibitors. In this study, novel azole derivatives of Echinocystic acid (EA), a natural pentacyclic triterpenoid, were synthesized through molecular hybridization to enhance hypoglycemic potential. Compound A4 exhibited superior α-glucosidase inhibition (IC₅₀ = 2.72 μM) than that of EA (IC₅₀ = 59.91 μM), and acarbose (IC₅₀ = 342.0 μM). Kinetic analysis revealed mixed-type inhibition (Ki = 15.31 μM, Kis = 10.23 μM), suggesting ternary complex formation. Analysis by spectroscopic studies confirmed A4 altered the enzyme's microenvironment and secondary structure. The combination of molecular docking and molecular dynamics simulations further elucidated the interaction between A4 and α-glucosidase. A4 enhanced binding stability through π-cation and π-π stacking interactions, with low RMSD values indicating structural stability. In vivo studies showed that A4 has an excellent safety profile, with no organ damage observed at a single dose of 0.5 g/kg. In a sucrose loading test in normal mice, A4 demonstrated glucose control comparable to that of acarbose at the same dose. Diabetic mice treated with A4 exhibited reduced fasting blood glucose, improved glucose tolerance, lipid normalization, and antioxidant effects, underscoring its therapeutic promise.

B vitamins are essential for energy metabolism, nervous health, blood production, and the immune system. Their quantification in nutritional supplements and food is mandatory to manage a correct daily intake and dosage. In this study, a fast and sustainable method for the analysis of 8 B vitamins (VB₁, VB₂, VB₃, nicotinamide, VB₅, VB₆, VB₉, VB₁₂) in real samples using a 2D-carbon microfiber fractionation system combined with a triple quadrupole mass spectrometer (2DμCFs-QqQ-MS/MS) is presented. The method shortens the analysis time to 5 min, showing high sensitivities (LODs: 1.7-13.7 ng mL^-1, LOQs: 5.5-45.7 ng mL^-1, obtained with standard solutions), good reproducibility (RSDs <15 %), and strong linear correlations (R² > 0.997). When applied for B vitamin determination in nutritional supplements, results matched product label values at a 95 % confidence level, with batch reproducibility never exceeding 5 %. Furthermore, coupling a 2D-carbon microfiber fraction system with a quadrupole time-of-flight high-resolution mass spectrometry (2DμCFs-QTOF-HRMS) it is possible to carry out quick monitoring of B vitamin contents together with impurity evaluation in real samples.