Histological Study and LYVE-1 Immunolocalization of Mouse Mesenteric Lymph Nodes with “In Vivo Cryotechnique”

The “in vivo cryotechnique” (IVCT) is a powerful tool to directly freeze living animal organs in order to maintain biological components in frozen tissues, reflecting their native states. In this study, mesenteric lymph nodes of living mice were directly frozen with IVCT, and we did morphological studies and immunohistochemical analyses on a hyaluronic acid receptor, LYVE-1. In lymph nodes, widely open lymphatic sinuses were observed, and many lymphocytes adhered to inner endothelial cells along subcapsular sinuses. The LYVE-1 was clearly immunolocalized at inner endothelial cells of subcapsular sinuses, as well as those of medullary sinuses. Conventional pre-embedding electron microscopy also showed LYVE-1 immunolocalization along both the apical and basal sides of cell membranes of inner endothelial cells. By triple-immunostaining for LYVE-1, smooth muscle actin, and type IV collagen, the LYVE-1 was immunolocalized only in the inner endothelial cells, but not in outer ones which were surrounded by collagen matrix and smooth muscle cells. Thus, the functional morphology of lymph nodes in vivo was demonstrated and LYVE-1 immunolocalization in inner endothelial cells of subcapsular sinuses suggests hyaluronic acid incorporation into lymph node parenchyma

Correlation between serum esterase polymorphism and production performance of Yuxi fat-tailed sheep

The polymorphism of serum esterase (Es) of Henan Yuxi fat-tailed sheep was detected through polyacrylamide gel electrophoresis (PAGE), and the correlation between serum esterase and productivity was analyzed. The research result indicated that there are two alleles on the Es loci of Henan Yuxi fat-tailed sheep: Es+ and Es-. The gene frequencies of Es+ and Es- were 0.55 and 0.45, respectively. Besides, the frequencies of three genotypes (Es++, Es+- and Es--) are 0.425, 0.250 and 0.325, respectively. The recommended height of Es++ genotype is significantly higher than that of Es+- genotype (P<0.05), but the above two produce indistinctive difference in recommended height with Es-- genotype (P>0.05). The chest circumference of Es++ genotype is significantly higher than that of Es-- (P<0.05), but the above two produce indistinctive difference in chest circumference with Es+- genotype (P>0.05). Es exerts no significant impact on other indexes (P>0.05).Keywords: Henan Yuxi fat-tailed sheep, serum esterase (Es), polymorphismAfrican Journal of Biotechnology Vol. 12(9), pp. 986-98

A Benchmark for Accurate GPCR Ligand Binding Affinity Prediction with Free Energy Perturbation

G protein-coupled receptors (GPCRs) are among the most important drug targets in the pharmaceutical industry. Free energy perturbation (FEP), which can accurately predict the relative binding free energies of drug molecules, is now widely used in drug discovery. With the development of structural biology tools such as cryoelectron-microscopy (cryo-EM), the structures of a large number of GPCRs have been resolved, which provides the basis for FEP calculations. In this study, we developed an FEP protocol for GPCR FEP calculation. We performed calculations on 226 perturbation pairs of 139 ligands against 8 GPCRs, spanning 12 datasets (A2A , mGlu5 , D3, OX2 , CXCR4, β1, δ and TA1 receptors) and obtained promising results, particularly for agonist ligands in the TA1 datasets (R2, 0.58, RMSE, 1.07 kcal · mol−1 ). The average R2 is 0.61 and the average RMSE is 0.94 kcal · mol−1 , which is comparable to experimental accuracy(<1 kcal · mol−1 ). We also investigated factors that impact the accuracy of FEP results, including ligand binding pose, water placement, and protein structure. Our input structures for FEP calculation are publicly available as a benchmark dataset for future GPCR-FEP studies (https://doi.org/10.5281/zenodo.7988248). This represents the largest collection of GPCR FEP calculations known to us thus far. This work is expected to significantly contribute to the advancement of GPCR-targeted drug discovery

4862F, a New Inhibitor of HIV-1 Protease, from the Culture of Streptomyces I03A-04862

We have isolated an extraordinary pentapeptide, called 4862F, from the culture broth of Streptomyces albosporus I03A-04862 by Diaion HP-20 macroporous adsorbent resin column, ODS-A and Sephadex LH-20 chromatography, followed by preparative HPLC. This peptide shows inhibitory activity against HIV-1 protease. The structure was elucidated by spectroscopic approaches, including ESI-MS and various NMR methods. Absolute configuration of the amino acid residues in 4862F was defined using Marfey’s method, and the structure was identified as N,N,N-(trimethylated)-Tyr-L-Leu-L-Val-L-Leu-(dehydrated)-His. The peptide 4862F displays inhibitory activity against HIV-1 protease, with IC50 values of 15.26 nM, using a fluorescence-based assay