Cysteine improves boar sperm quality via glutathione biosynthesis during the liquid storage

Zhu Zhendong,Zeng Yao,Zeng Wenxian 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.2

Objective: Sperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage. Methods: Sperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4- HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting. Results: Compared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine. Conclusion: These data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress. Objective: Sperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage.Methods: Sperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4-HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting.Results: Compared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine.Conclusion: These data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress.

Polymerization of Vinyl Acetate Initiated by Hydrosilane in the Presence of Platinum Complex

Ming Yuan,Wenxian Zhu,Jiaxing Lv,Panpan Zhang,Huadong Tang 한국고분자학회 2021 폴리머 Vol.45 No.3

In this work, a series of hydrosilanes including phenylsilane, diphenylsilane, triethylsilane (TES), and tris(trimethylsilyl)silane combined with catalytical amount of platinum complex such as dichloro(1,5-cyclooctadiene) platinum (COD) and dichloro(dicyclopentadienyl)platinum have been used to initiate the polymerization of vinyl acetate (VAc) at 70-95 ℃. An ultrahigh molecular weight PVAc with number-average molecular weight (Mn) up to 1.17×10<SUP>6</SUP> Da and polydispersity index (PDI) of 2.59 has been synthesized using TES as an initiator in the presence of 9.7 ppm of COD. A kinetic study indicates that the polymerization at VAc/TES/COD molar ratio = 3.0×10<SUP>5</SUP> : 60 : 1 smoothly reached 81.0% conversion in 28.0 h at 85 ℃, producing PVAc with Mn increasing linearly from 1.41×105 to 6.01×10<SUP>5</SUP> Da with the increase of monomer conversion. A mechanistic investigation revealed that COD was firstly reduced by reductive TES, producing Pt nanoparticles and corresponding silane radicals to initiate the polymerization of VAc.

Rational Design and Molecular Engineering of Peptide Aptamers to Target Human Pancreatic Trypsin in Acute Pancreatitis

Weiyi Shao,Wenxian Zhu,Yanhua Wang,Jingwei Lu,Ge Jin,Yixin Wang,Wenli Su 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.1

Human pancreatic trypsin (hPT) is an established target for acute pancreatitis (AP) therapeutics. Here, a bioinformatics protocol of protein docking, peptide refinement, dynamics simulation and affinity analysis was described to perform rational design and molecular engineering of hPT peptide aptamers. Protein docking was employed to model the intermolecular interactions between hPT and its cognate inhibitory protein, the human pancreatic trypsin inhibitor (hTI). A number of peptide fragments were cut out from the interaction sites of docked hPT–hTI complexes, from which a decapeptide fragment 13LNGCTLEYRP22 was found to exhibit potent inhibition against hPT (Ki = 5.3 ± 0.8 μM). We also carried out alanine scanning and virtual mutagenesis to systematically examine the independent contribution of peptide residues to binding affinity, and the harvested knowledge were then used to guide modification and optimization of the decapeptide fragment. Subsequently, inhibition studies of nine promising candidates against recombinant hPT were conducted, from which four samples were successfully identified to have high or moderate potency (Ki < 10 μM). In particular, the peptides LQVCTLEYCN and LQICTLEYCT were found to inhibit hPT activity significantly (Ki = 0.23 ± 0.04 and 0.85 ± 0.18 μM, respectively). Structural analysis of hPT– peptide complex systems unraveled diverse chemical interactions such as hydrogen bonds, salt bridges and hydrophobic forces across the complex interfaces.

Enhanced electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode material co-coated by graphene/TiO2

Dang Mengyue,Li Ying,Xu Chaoxiang,He Yulin,Yu Chunpeng,Liu Wenbo,Jin Hongming,Zhu Mingyuan,Zhang Jiujun,Li Wenxian 한국물리학회 2021 Current Applied Physics Vol.32 No.-

The electrochemical performances of LiNi0.5Co0.2Mn0.3O2 (NCM523) layered cathode material, such as poor rate capacity and cycling stability caused by undesirable intrinsic conductivity and low rate of lithium ion transportation, are not fairly good especially at elevated rate and cut-off voltage. To improve these properties, in this study, the co-coating layer of graphene and TiO2 was constructed on NCM523 surface. The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. The enhancement of cycle performance and rate capacity was contributed to the uniform co-modified surface, interacting each other and thus exhibiting synergistic effects.