Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids...Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus.However,there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens.In this article,we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4.Methods: To evaluate the tolerance of broilers for L-lysine·H2SO4,240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0,1%,4%,7% or 10% L-lysine·H2SO4(L-lysine content = 55%).Results: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects.However,4%,7% or 10% Llysine·H2SO4 supplementation produced negative responses on broiler performance,carcass characteristics,blood biochemistry,and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.Conclusion: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance,carcass characteristics,blood biochemistry,intestinal morphology and liver pathology in broilers,but supplementation with 4%,7% or 10% L-lysine·H2SO4 produced a negative response,particularly with respect to intestinal morphology and liver pathology.展开更多
[Objectives]Protoplast fusion of two parental strains with weak L-lysine production ability was carried out to obtain new fusion strains with strong L-lysine production ability.[Methods]The effects of bacterial age,ly...[Objectives]Protoplast fusion of two parental strains with weak L-lysine production ability was carried out to obtain new fusion strains with strong L-lysine production ability.[Methods]The effects of bacterial age,lysozyme concentration,enzymolysis temperature and time on the protoplast formation rate and regeneration rate were investigated by single factor experiments.On this basis,with the protoplast formation rate as an index,the protoplast preparation process was optimized by an orthogonal experiment.[Results]Bacterial age and enzymolysis time had a greater impact on the protoplast formation rate,followed by enzymolysis temperature and lysozyme concentration.The optimal process for the preparation of L-lysine-producing Escherichia coli protoplasts was to prepare parental protoplasts from bacterial cells cultured for 15 h in the late logarithmic growth phase by enzymolysis with 0.8 mg/ml lysozyme at 37℃for 180 min and promote fusion with PEG6000.In order to facilitate the screening of fusion protoplasts,the empty plasmids p ET-28a and p ET-Duet were transformed into L-lysine-producing E.coli,respectively,and strains p ET-28a-lys01 and p ET-Duet-lys01 were obtained.Fusion strains were then obtained through protoplast fusion.Double-resistance KA1-10were screened on plates containing kanamycin and ampicillin,and a high-yielding fusion strain KA8,which produced L-lysine,was screened by fermentation experiments finally.[Conclusions]The results of this study provide a reference method for further improving the yield of L-lysine and other amino acid strains.展开更多
The aim of this study was to estimate the effect of L-lysine on nodule formation by rat bone marrow cells in vitro. In this study, L-lysine was added to medium for mesenchymal stem cell culture to promote proliferatio...The aim of this study was to estimate the effect of L-lysine on nodule formation by rat bone marrow cells in vitro. In this study, L-lysine was added to medium for mesenchymal stem cell culture to promote proliferation and differentiation of the cells, and then nodule formation was estimated in an in vitro rat bone marrow cell culture. Bone marrow cells from the bone shafts of the femora of Fischer 344 rats were cultured in minimum essential medium with 20 μl of L-lysine solution at 10﹣4, 10﹣5, 10﹣6, 10﹣7 or 10﹣8 M. Dexamethasone was also added to the medium at 10 nM for differentiation of stem cells from bone marrow into osteoblast progenitor cells. The subculture was performed for 2 weeks. The quantity of osteocalcin in rat bone marrow cell culture with dexamethasone was 392 ng/ml. In the medium with dexamethasone and 10﹣8 M L-lysine, the quantity of osteocalcin was 437 ng/ml. Nodules only formed upon addition of 20 μl of L-lysine at 10﹣8 M. It was indicated that 10﹣8 M L-lysine should be the optimal concentration for calcification. For nodule formation by rat bone marrow cells in vitro, the optimum concentration of L-lysine in culture medium might be 20 μl of 10﹣8 M. L-lysine could play an important role in matrix production for bone formation in vitro.展开更多
Green solvents for cellulose dissolution is a key topic for green chemistry,especially natural cellulose with high molecular weight,and there are scarce solvents reported.Deep eutectic solvent(DES)is a typical kind of...Green solvents for cellulose dissolution is a key topic for green chemistry,especially natural cellulose with high molecular weight,and there are scarce solvents reported.Deep eutectic solvent(DES)is a typical kind of green solvent that has been attracted much attention recently.Here,high molecular weight natural cellulose(DP>3000)was first isolated from wheat straw and then be directly dissolved in the choline/L-lysine(Ch/Lys)DES.The solution owns excellent stability,and the solubility reaches^5%.Rheological studies revealed that the natural cellulose can be well dispersed in the DES solution and showed gelation at high concentrations.The dissolved cellulose can be regenerated when the dilute acid aqueous solution was added into the solution.It provides an energy conversation and an environmentally friendly route to prepare a cellulose solution,which makes it possible to convert cellulose to valuable chemicals and materials in its homogeneous solution.展开更多
α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment ...α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.展开更多
Background Hyperglycemia in brain and spinal cord could aggravate neurologic impairment. Recent studies showed that L-lysine monohydrochlonde (LMH) could increase the insulin secretion and regulate the blood glucose...Background Hyperglycemia in brain and spinal cord could aggravate neurologic impairment. Recent studies showed that L-lysine monohydrochlonde (LMH) could increase the insulin secretion and regulate the blood glucose level. The aim of the present study was to investigate the effects of LMH on pancreatic islet B cells, the levels of endogenous insulin and blood glucose in spinal cord injured rats.Methods Forty male Wistar rats were divided into four groups, namely, normal control group, model group, high-dose LMH group (621.5 mg/kg equal to LMH 1/8 LD50), and low-dose LMH group (310.8 mg/kg equal to LMH 1/16 LD50). The model of spinal cord injured rat was established by hemi-transection at the lower right thoracic spinal cord. LMH was administered via intraperitoneal injection once spinal cord injury was produced in rats. All rats were sacrificed 48 hours after spinal cord injured. The effects of LMH on pancreatic islet B cells, the content of endogenous insulin, end the level of blood glucose were observed with immunohistochemical method, radioimmunoassay method, end biochemical analyzer, respectively. Results The insulin immunohistochemical intensities of islet B cells were significantly weaker in model group then those in normal control group (P 〈0.01). The levels of endogenous insulin were significantly lower and the blood glucose levels were significantly higher in model group than those in normal control group (P 〈0.01). The insulin immunohistochemical intensities of islet B cells were significantly stronger in high-dose LMH group then those in model group (P〈0.05). In addition, we found that the levels of endogenous insulin were significantly higher and the blood glucose levels were significantly lower in high-dose LMH group then those in model group (P 〈0.05). There were no significant differences in the insulin immunohistochemical intensities of islet B cells, the levels of endogenous insulin and the blood glucose between low-dose LMH group and model group (P 〉0.05). Conclusion LMH, but dose-dependent, might participate in the regulation of pancreatic islet B cells, and then reduce the blood glucose levels in the spinal cord injured rats.展开更多
The high amount of l-lysine can increase the potential risk of cardiovascular disease.Additionally,2-methoxy benzaldehyde(2-MB)has high toxicity and can easily pollute the environment.In this work,carbon quantum dots(...The high amount of l-lysine can increase the potential risk of cardiovascular disease.Additionally,2-methoxy benzaldehyde(2-MB)has high toxicity and can easily pollute the environment.In this work,carbon quantum dots(CQDs)can be encapsulated into Eu-BTB(H_(3)BTB=1,3,5-tri(4-carboxyphenyl)benzene),forming the multi-emission composite material Eu-BTB@CQDs.It has two emissions peaks(617 nm for Eu and 470 nm for CQDs).Eu-BTB@CQDs can be applied as bi-functional ratiometric“off&on”luminescent sensor for l-lysine and 2-MB with high sensitivity and selectivity,the low limit of detection(LOD)for l-lysine is 3.68μmol/L and for 2-MB is 0.54μmol/L,respectively.Additionally,Eu-BTB@CQDs can quantitatively discriminate l-lysine in the mixed d-and l-lysine water solutions(five different concentrations ratio of l/d-lysine has been set)makes the chiral detection of l-lysine are more meaningful.On the other hand,Eu-BTB@CQDs also can detect 2-MB over 4-methoxybenzaldehyde(4-MB)with high selectivity.Further the detection of 2-MB and l-lysine in the lake water real samples with the reasonable recovery rate.Finally,the detection mechanisms for l-lysine and 2-MB were also investigated and discussed in detail.展开更多
It is highly desired to accurately and selectively detect and image intracellular L-lysine and pH in biological systems because they could act as the biomarkers in certain abnormal conditions and may give us a warning...It is highly desired to accurately and selectively detect and image intracellular L-lysine and pH in biological systems because they could act as the biomarkers in certain abnormal conditions and may give us a warning of the occurrence of diseases.It has been attracted more focuses to design new ratiometric fluorescent probe for monitoring L-lysine and pH to improve detection accuracy.Carbonized polymer dots(CPDs),which possess carbon/polymer hybrid structure rather than pure carbon structure and constitute of a carbon core and large amounts of functional groups/polymer chains on the surface,rise up as a new type of fluorescent nanomaterials and especially display many advantages for bioanalysis.In this study,o-phenylenediamine(o-PD)and poly(styrene-co-maleic anhydride)(PSMA)are used as the precursors to synthesize the desired CPDs through one-step hydrothermal amide method.The prepared CPDs display two well-resolved fluorescence emission bands,i.e.,a very weak emission centered at 470 nm in blue region and a strong emission centered at 558 nm in yellow region.It is found that the two emissions are both responsive to L-lysine based on the surface passivation mechanism,whereas,only the yellow emission is responsive to pH due to the protonation/deprotonation process of the amino groups.Based on the different responsive behaviors,ratiometric detection and imaging of L-lysine and pH are achieved.The prepared ratiometric CPDs probe is successfully applied for L-lysine and pH sensing and imaging at two emission channels in live cell and zebrafish with satisfactory results.展开更多
基金The present study was supported by the 111 Project(B16044)of China
文摘Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus.However,there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens.In this article,we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4.Methods: To evaluate the tolerance of broilers for L-lysine·H2SO4,240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0,1%,4%,7% or 10% L-lysine·H2SO4(L-lysine content = 55%).Results: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects.However,4%,7% or 10% Llysine·H2SO4 supplementation produced negative responses on broiler performance,carcass characteristics,blood biochemistry,and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.Conclusion: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance,carcass characteristics,blood biochemistry,intestinal morphology and liver pathology in broilers,but supplementation with 4%,7% or 10% L-lysine·H2SO4 produced a negative response,particularly with respect to intestinal morphology and liver pathology.
基金Supported by the Focus on Research and Development Plan in Shandong Province(2019JZZY011003,2020CXGC010603)National Natural Science Foundation of China(31801527)。
文摘[Objectives]Protoplast fusion of two parental strains with weak L-lysine production ability was carried out to obtain new fusion strains with strong L-lysine production ability.[Methods]The effects of bacterial age,lysozyme concentration,enzymolysis temperature and time on the protoplast formation rate and regeneration rate were investigated by single factor experiments.On this basis,with the protoplast formation rate as an index,the protoplast preparation process was optimized by an orthogonal experiment.[Results]Bacterial age and enzymolysis time had a greater impact on the protoplast formation rate,followed by enzymolysis temperature and lysozyme concentration.The optimal process for the preparation of L-lysine-producing Escherichia coli protoplasts was to prepare parental protoplasts from bacterial cells cultured for 15 h in the late logarithmic growth phase by enzymolysis with 0.8 mg/ml lysozyme at 37℃for 180 min and promote fusion with PEG6000.In order to facilitate the screening of fusion protoplasts,the empty plasmids p ET-28a and p ET-Duet were transformed into L-lysine-producing E.coli,respectively,and strains p ET-28a-lys01 and p ET-Duet-lys01 were obtained.Fusion strains were then obtained through protoplast fusion.Double-resistance KA1-10were screened on plates containing kanamycin and ampicillin,and a high-yielding fusion strain KA8,which produced L-lysine,was screened by fermentation experiments finally.[Conclusions]The results of this study provide a reference method for further improving the yield of L-lysine and other amino acid strains.
文摘The aim of this study was to estimate the effect of L-lysine on nodule formation by rat bone marrow cells in vitro. In this study, L-lysine was added to medium for mesenchymal stem cell culture to promote proliferation and differentiation of the cells, and then nodule formation was estimated in an in vitro rat bone marrow cell culture. Bone marrow cells from the bone shafts of the femora of Fischer 344 rats were cultured in minimum essential medium with 20 μl of L-lysine solution at 10﹣4, 10﹣5, 10﹣6, 10﹣7 or 10﹣8 M. Dexamethasone was also added to the medium at 10 nM for differentiation of stem cells from bone marrow into osteoblast progenitor cells. The subculture was performed for 2 weeks. The quantity of osteocalcin in rat bone marrow cell culture with dexamethasone was 392 ng/ml. In the medium with dexamethasone and 10﹣8 M L-lysine, the quantity of osteocalcin was 437 ng/ml. Nodules only formed upon addition of 20 μl of L-lysine at 10﹣8 M. It was indicated that 10﹣8 M L-lysine should be the optimal concentration for calcification. For nodule formation by rat bone marrow cells in vitro, the optimum concentration of L-lysine in culture medium might be 20 μl of 10﹣8 M. L-lysine could play an important role in matrix production for bone formation in vitro.
基金This work is supported by the National Natural Science Foundation of China(No.51673180 and 51873201).
文摘Green solvents for cellulose dissolution is a key topic for green chemistry,especially natural cellulose with high molecular weight,and there are scarce solvents reported.Deep eutectic solvent(DES)is a typical kind of green solvent that has been attracted much attention recently.Here,high molecular weight natural cellulose(DP>3000)was first isolated from wheat straw and then be directly dissolved in the choline/L-lysine(Ch/Lys)DES.The solution owns excellent stability,and the solubility reaches^5%.Rheological studies revealed that the natural cellulose can be well dispersed in the DES solution and showed gelation at high concentrations.The dissolved cellulose can be regenerated when the dilute acid aqueous solution was added into the solution.It provides an energy conversation and an environmentally friendly route to prepare a cellulose solution,which makes it possible to convert cellulose to valuable chemicals and materials in its homogeneous solution.
文摘α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.
文摘Background Hyperglycemia in brain and spinal cord could aggravate neurologic impairment. Recent studies showed that L-lysine monohydrochlonde (LMH) could increase the insulin secretion and regulate the blood glucose level. The aim of the present study was to investigate the effects of LMH on pancreatic islet B cells, the levels of endogenous insulin and blood glucose in spinal cord injured rats.Methods Forty male Wistar rats were divided into four groups, namely, normal control group, model group, high-dose LMH group (621.5 mg/kg equal to LMH 1/8 LD50), and low-dose LMH group (310.8 mg/kg equal to LMH 1/16 LD50). The model of spinal cord injured rat was established by hemi-transection at the lower right thoracic spinal cord. LMH was administered via intraperitoneal injection once spinal cord injury was produced in rats. All rats were sacrificed 48 hours after spinal cord injured. The effects of LMH on pancreatic islet B cells, the content of endogenous insulin, end the level of blood glucose were observed with immunohistochemical method, radioimmunoassay method, end biochemical analyzer, respectively. Results The insulin immunohistochemical intensities of islet B cells were significantly weaker in model group then those in normal control group (P 〈0.01). The levels of endogenous insulin were significantly lower and the blood glucose levels were significantly higher in model group than those in normal control group (P 〈0.01). The insulin immunohistochemical intensities of islet B cells were significantly stronger in high-dose LMH group then those in model group (P〈0.05). In addition, we found that the levels of endogenous insulin were significantly higher and the blood glucose levels were significantly lower in high-dose LMH group then those in model group (P 〈0.05). There were no significant differences in the insulin immunohistochemical intensities of islet B cells, the levels of endogenous insulin and the blood glucose between low-dose LMH group and model group (P 〉0.05). Conclusion LMH, but dose-dependent, might participate in the regulation of pancreatic islet B cells, and then reduce the blood glucose levels in the spinal cord injured rats.
基金supported financially by Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2019ZD15).
文摘The high amount of l-lysine can increase the potential risk of cardiovascular disease.Additionally,2-methoxy benzaldehyde(2-MB)has high toxicity and can easily pollute the environment.In this work,carbon quantum dots(CQDs)can be encapsulated into Eu-BTB(H_(3)BTB=1,3,5-tri(4-carboxyphenyl)benzene),forming the multi-emission composite material Eu-BTB@CQDs.It has two emissions peaks(617 nm for Eu and 470 nm for CQDs).Eu-BTB@CQDs can be applied as bi-functional ratiometric“off&on”luminescent sensor for l-lysine and 2-MB with high sensitivity and selectivity,the low limit of detection(LOD)for l-lysine is 3.68μmol/L and for 2-MB is 0.54μmol/L,respectively.Additionally,Eu-BTB@CQDs can quantitatively discriminate l-lysine in the mixed d-and l-lysine water solutions(five different concentrations ratio of l/d-lysine has been set)makes the chiral detection of l-lysine are more meaningful.On the other hand,Eu-BTB@CQDs also can detect 2-MB over 4-methoxybenzaldehyde(4-MB)with high selectivity.Further the detection of 2-MB and l-lysine in the lake water real samples with the reasonable recovery rate.Finally,the detection mechanisms for l-lysine and 2-MB were also investigated and discussed in detail.
基金financially supported by the National Natural Science Foundation of China(Nos.21874001,21575004)the Foundation for Innovation Team of Bioanalytical Chemistry of Anhui Province。
文摘It is highly desired to accurately and selectively detect and image intracellular L-lysine and pH in biological systems because they could act as the biomarkers in certain abnormal conditions and may give us a warning of the occurrence of diseases.It has been attracted more focuses to design new ratiometric fluorescent probe for monitoring L-lysine and pH to improve detection accuracy.Carbonized polymer dots(CPDs),which possess carbon/polymer hybrid structure rather than pure carbon structure and constitute of a carbon core and large amounts of functional groups/polymer chains on the surface,rise up as a new type of fluorescent nanomaterials and especially display many advantages for bioanalysis.In this study,o-phenylenediamine(o-PD)and poly(styrene-co-maleic anhydride)(PSMA)are used as the precursors to synthesize the desired CPDs through one-step hydrothermal amide method.The prepared CPDs display two well-resolved fluorescence emission bands,i.e.,a very weak emission centered at 470 nm in blue region and a strong emission centered at 558 nm in yellow region.It is found that the two emissions are both responsive to L-lysine based on the surface passivation mechanism,whereas,only the yellow emission is responsive to pH due to the protonation/deprotonation process of the amino groups.Based on the different responsive behaviors,ratiometric detection and imaging of L-lysine and pH are achieved.The prepared ratiometric CPDs probe is successfully applied for L-lysine and pH sensing and imaging at two emission channels in live cell and zebrafish with satisfactory results.