In order to explore the effect of manganese on DNA-protein crosslinks （DPC） of testicle in chicken. 500, 800, 1 700 mg·kg^-1 MnC12 were added to forage to establish the model of the sub-chronic manganese poison...In order to explore the effect of manganese on DNA-protein crosslinks （DPC） of testicle in chicken. 500, 800, 1 700 mg·kg^-1 MnC12 were added to forage to establish the model of the sub-chronic manganese poisoning. After 30, 60 and 90 d, testicles were taken out to detect hydroxyl radical inhibiting capacity and DPC content. The results showed that compared with control group, hydroxyl radical inhibiting capacity significantly decreased and DPC content notably increased, and there was a time-dose relationship. It demonstrated that manganese could decrease the inhibitng capacity of hydroxyl radical, increase the content of hydroxyl and DPC, and induce DNA damage.展开更多
The crosslinking mechanism of glyoxal and asparagine was analyzed,and the relationship between the mechanism and practical performances of soy protein-based adhesives was also discussed.It is shown that when pH=1 and ...The crosslinking mechanism of glyoxal and asparagine was analyzed,and the relationship between the mechanism and practical performances of soy protein-based adhesives was also discussed.It is shown that when pH=1 and 3,glyoxal reacted with asparagine in the form of major cyclic ether compounds.When pH=5,glyoxal reacted with asparagine in two structural forms of sodium glycollate and cyclic ether compounds.However,amidogens of asparagine were easy to develop protonation under acid conditions.Supplemented by the instability of cyclic ether compounds,the reaction activity and reaction degree between glyoxal and asparagine were relatively small.Under alkaline conditions,glyoxal mainly reacted with asparagine in the form of sodium glycollate.With the increase of pH,the polycondensation was more sufficient and the produced polycondensation products were more stable.The reaction mechanism between glyoxal and asparagine had strong correspondence to the practical performances of the adhesives.Glyoxal solution could develop crosslinking reactions with soy protein under both acid and alkaline conditions.Bonding strength and water resistance of the prepared soy protein-based adhesives were increased significantly.When pH>7,glyoxal had relatively high reaction activity and reaction intensity with soy protein,and the prepared adhesives had high crosslinking density and cohesion strength,showing relatively high bonding strength,water resistance and thermal stability.展开更多
Epoxy resin (EPR) was used to crosslink with Camellia oleifera Abel.protein to prepare wood adhesive,and the bonding performance and curing characteristics of which were mainly investigated,and the synthesis mechanism...Epoxy resin (EPR) was used to crosslink with Camellia oleifera Abel.protein to prepare wood adhesive,and the bonding performance and curing characteristics of which were mainly investigated,and the synthesis mechanism was also discussed by using model compounds.The experimental results show that EPR can significantly improve the bonding performance of Camellia oleifera Abel.protein-based adhesive,and the maximum of which reaches 0.72 MPa satisfies the strength requirement of Type II plywood in GB/T 17657-2013.After alkali treatment,the protein can more easily crosslink with EPR at low curing temperature,and the adhesive has high degree of crystallinity of curing products,high degree of crosslinking reaction,and high bonding strength.The reaction mechanism of EPR-modified Camellia oleifera Abel.protein adhesive can be divided into resinification phase and curing phase.展开更多
Intermediate filaments are one of the key components of the cytoskeleton in eukaryotic cells, and their mechanical properties are found to be equally important for physiological function and disease. While the mechani...Intermediate filaments are one of the key components of the cytoskeleton in eukaryotic cells, and their mechanical properties are found to be equally important for physiological function and disease. While the mechanical properties of single full length filaments have been studied, how the mechanical properties of crosslinks affect the mechanical property of the intermediate filament network is not well understood. This paper applies a mesoscopic model of the intermediate network with varied crosslink strengths to investigate its failure mechanism under the extreme mechanical loading. It finds that relatively weaker crosslinks lead to a more flaw tolerant intermediate filament network that is also 23% stronger than the one with strong crosslinks. These findings suggest that the mechanical properties of interfacial components are critical for bioinspired designs which provide intriguing mechanical properties.展开更多
Formaldehyde fixation is the main method for crosslinking cellular proteins prior to their usage in immunocytochemistry. In order to create these links, formaldehyde undergoes a Mannich reaction in which the formaldeh...Formaldehyde fixation is the main method for crosslinking cellular proteins prior to their usage in immunocytochemistry. In order to create these links, formaldehyde undergoes a Mannich reaction in which the formaldehyde forms a methylene bridge between the aminogroup of two amino acids. Crosslinking increases protein stability allowing for more accurate preservation of in vivo conformations which in turn increases binding affinity of fluorochrome conjugated antibodies for fluorescent imaging. Formaldehyde is also a known carcinogen as classified by the National Cancer Institute. Malonic acid, a green, plant-based, water-soluble, and relatively inexpensive polycarboxylic acid has been shown to undergo crosslinking of proteins through an unknown mechanism. To test whether malonic acid can crosslink proteins within cells we fixed SH-5YSY cells with either malonic acid or formaldehyde and then stained with a fluorochrome conjugated antibody for the cytoskeletal protein α-tubulin. The cells were then imaged 72 hours after fixation. We observed a non-significant difference in the fluorescence of immunostained SH-5YSY cells fixed with malonic acid as compared to paraformaldehyde (p-value = 0.2469, ANOVA). In addition, we have created a theoretical mechanism showing malonic acid forming a propyl bridge for crosslinking proteins in a similar mechanism to that of formaldehyde. Here, we show that malonic acid is able to fix cells and retain fluorescence just as well as paraformaldehyde up to 72 hours after fixation and present several possible mechanisms for this chemical process.展开更多
This work presents an approach to build a high-performance, low-viscous and replaceable separation matrix, semi-crosslinked polyacrylamide （semi-CPA） capillary gel electrophoresis. Non- denatured basic proteins, suc...This work presents an approach to build a high-performance, low-viscous and replaceable separation matrix, semi-crosslinked polyacrylamide （semi-CPA） capillary gel electrophoresis. Non- denatured basic proteins, such as lysozyme, cytochrome C, ribonuclease A and trypsin were separa- ted. The impacts of monomer and cross-linker concentrations on protein separation were studied, and the ability of dynamic capillary inner wall coating was demonstrated. The UV absorption interfer- ence by semi-CPA gel matrix was successfully overcome by a partial filling technique, which results in sensitivity 20 times higher than other protein separation method. The excellent separation ability, reproducibility and dynamic coating ability made semi-CPA an ideal separation media in both capillar- y electrophoresis and microfluidic chip separation scheme.展开更多
文摘In order to explore the effect of manganese on DNA-protein crosslinks （DPC） of testicle in chicken. 500, 800, 1 700 mg·kg^-1 MnC12 were added to forage to establish the model of the sub-chronic manganese poisoning. After 30, 60 and 90 d, testicles were taken out to detect hydroxyl radical inhibiting capacity and DPC content. The results showed that compared with control group, hydroxyl radical inhibiting capacity significantly decreased and DPC content notably increased, and there was a time-dose relationship. It demonstrated that manganese could decrease the inhibitng capacity of hydroxyl radical, increase the content of hydroxyl and DPC, and induce DNA damage.
基金Funded by the National Natural Science Foundation of China(No.32160348)the Department Program of Guizhou Province(No.ZK[2021]162)+1 种基金the Guizhou Province Science and Technology Plan Project(No.[2020]1Y128)the Forestry Department Foundation of Guizhou Province of China(Nos.J[2022]21 and[2020]C14)。
文摘The crosslinking mechanism of glyoxal and asparagine was analyzed,and the relationship between the mechanism and practical performances of soy protein-based adhesives was also discussed.It is shown that when pH=1 and 3,glyoxal reacted with asparagine in the form of major cyclic ether compounds.When pH=5,glyoxal reacted with asparagine in two structural forms of sodium glycollate and cyclic ether compounds.However,amidogens of asparagine were easy to develop protonation under acid conditions.Supplemented by the instability of cyclic ether compounds,the reaction activity and reaction degree between glyoxal and asparagine were relatively small.Under alkaline conditions,glyoxal mainly reacted with asparagine in the form of sodium glycollate.With the increase of pH,the polycondensation was more sufficient and the produced polycondensation products were more stable.The reaction mechanism between glyoxal and asparagine had strong correspondence to the practical performances of the adhesives.Glyoxal solution could develop crosslinking reactions with soy protein under both acid and alkaline conditions.Bonding strength and water resistance of the prepared soy protein-based adhesives were increased significantly.When pH>7,glyoxal had relatively high reaction activity and reaction intensity with soy protein,and the prepared adhesives had high crosslinking density and cohesion strength,showing relatively high bonding strength,water resistance and thermal stability.
基金Funded by the Science and Technology Department Program of Guizhou Province (ZK[2021]162 and [2019]2325)the Special Project of"Doctor Professor Service Group of Kaili University (BJFWT201906)+1 种基金the Cultivation Project of Guizhou University of China ([2019]37)the Camellia Engineering Technology Research Center of Guizhou Province ([2018]5252)。
文摘Epoxy resin (EPR) was used to crosslink with Camellia oleifera Abel.protein to prepare wood adhesive,and the bonding performance and curing characteristics of which were mainly investigated,and the synthesis mechanism was also discussed by using model compounds.The experimental results show that EPR can significantly improve the bonding performance of Camellia oleifera Abel.protein-based adhesive,and the maximum of which reaches 0.72 MPa satisfies the strength requirement of Type II plywood in GB/T 17657-2013.After alkali treatment,the protein can more easily crosslink with EPR at low curing temperature,and the adhesive has high degree of crystallinity of curing products,high degree of crosslinking reaction,and high bonding strength.The reaction mechanism of EPR-modified Camellia oleifera Abel.protein adhesive can be divided into resinification phase and curing phase.
文摘Intermediate filaments are one of the key components of the cytoskeleton in eukaryotic cells, and their mechanical properties are found to be equally important for physiological function and disease. While the mechanical properties of single full length filaments have been studied, how the mechanical properties of crosslinks affect the mechanical property of the intermediate filament network is not well understood. This paper applies a mesoscopic model of the intermediate network with varied crosslink strengths to investigate its failure mechanism under the extreme mechanical loading. It finds that relatively weaker crosslinks lead to a more flaw tolerant intermediate filament network that is also 23% stronger than the one with strong crosslinks. These findings suggest that the mechanical properties of interfacial components are critical for bioinspired designs which provide intriguing mechanical properties.
文摘Formaldehyde fixation is the main method for crosslinking cellular proteins prior to their usage in immunocytochemistry. In order to create these links, formaldehyde undergoes a Mannich reaction in which the formaldehyde forms a methylene bridge between the aminogroup of two amino acids. Crosslinking increases protein stability allowing for more accurate preservation of in vivo conformations which in turn increases binding affinity of fluorochrome conjugated antibodies for fluorescent imaging. Formaldehyde is also a known carcinogen as classified by the National Cancer Institute. Malonic acid, a green, plant-based, water-soluble, and relatively inexpensive polycarboxylic acid has been shown to undergo crosslinking of proteins through an unknown mechanism. To test whether malonic acid can crosslink proteins within cells we fixed SH-5YSY cells with either malonic acid or formaldehyde and then stained with a fluorochrome conjugated antibody for the cytoskeletal protein α-tubulin. The cells were then imaged 72 hours after fixation. We observed a non-significant difference in the fluorescence of immunostained SH-5YSY cells fixed with malonic acid as compared to paraformaldehyde (p-value = 0.2469, ANOVA). In addition, we have created a theoretical mechanism showing malonic acid forming a propyl bridge for crosslinking proteins in a similar mechanism to that of formaldehyde. Here, we show that malonic acid is able to fix cells and retain fluorescence just as well as paraformaldehyde up to 72 hours after fixation and present several possible mechanisms for this chemical process.
基金Supported by the Key Project in the National Science ＆ Tech- nology Pillar Program During the Eleventh Five-Year Plan Pe- riod （2009BAK59B02）
文摘This work presents an approach to build a high-performance, low-viscous and replaceable separation matrix, semi-crosslinked polyacrylamide （semi-CPA） capillary gel electrophoresis. Non- denatured basic proteins, such as lysozyme, cytochrome C, ribonuclease A and trypsin were separa- ted. The impacts of monomer and cross-linker concentrations on protein separation were studied, and the ability of dynamic capillary inner wall coating was demonstrated. The UV absorption interfer- ence by semi-CPA gel matrix was successfully overcome by a partial filling technique, which results in sensitivity 20 times higher than other protein separation method. The excellent separation ability, reproducibility and dynamic coating ability made semi-CPA an ideal separation media in both capillar- y electrophoresis and microfluidic chip separation scheme.
