Intraocular pressure elevation can induce retinal ganglion cell death and is a clinically reversible risk factor for glaucoma,the leading cause of irreversible blindness.We previously demonstrated that casein kinase-2...Intraocular pressure elevation can induce retinal ganglion cell death and is a clinically reversible risk factor for glaucoma,the leading cause of irreversible blindness.We previously demonstrated that casein kinase-2 inhibition can promote retinal ganglion cell survival and axonal regeneration in rats after optic nerve injury.To investigate the underlying mechanism,in the current study we increased the intraocular pressure of adult rats to 75 mmHg for 2 hours and then administered a casein kinase-2 inhibitor(4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole)by intravitreal injection.We found that intravitreal injection of 4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole promoted retinal ganglion cell survival and reduced the number of infiltrating macrophages.Transcriptomic analysis showed that the mitogen activated protein kinase signaling pathway was involved in the response to intraocular pressure elevation but was not modulated by the casein kinase-2 inhibitors.Furthermore,casein kinase-2 inhibition downregulated the expression of genes(Cck,Htrsa,Nef1,Htrlb,Prph,Chat,Slc18a3,Slc5a7,Scn1b,Crybb2,Tsga10ip,and Vstm21)involved in intraocular pressure elevation.Our data indicate that inhibition of casein kinase-2 can enhance retinal ganglion cell survival in rats after acute intraocular pressure elevation via macrophage inactivation.展开更多
Protein colloidal nanoparticles(NPs)are ubiquitous present in nature and function as building blocks with multiple functions in both food formulations and biological processes.Food scientists are inspired by naturally...Protein colloidal nanoparticles(NPs)are ubiquitous present in nature and function as building blocks with multiple functions in both food formulations and biological processes.Food scientists are inspired by naturally occurring proteins to induce self-assembly behavior of protein by manipulating environmental parameters,providing opportunities to construct special and expected NPs.Zein and casein,the main proteins derived from corn and milk,are two examples of the most prevalently studied food proteins for nanoarchitectures in recent years.In this article,the compositions,structures,and physicochemical properties of these two proteins and casein derivatives are summarized as well as their interactions and characterizations.Strategies to fabricate zein-sodium caseinate based NPs are critically highlighted and illustrated.Particularly,applications such as encapsulation and delivery of bioactive compounds,producing food packaging for enhanced antioxidative and antimicrobial effects,and stabilization of emulsions to achieve fat replacement.Due to the imperative role of food proteins in diet composition,this review not only provides cutting-edge knowledge for nanoparticle construction but also opens new avenues for efficient utilization and exploitation of food proteins.展开更多
为了探讨昆仑雪菊醇提物对美拉德反应晚期糖基化终产物(advanced glycation end products,AGEs)生成的抑制作用,建立乳糖-酪蛋白和葡萄糖-赖氨酸-亚油酸两种模拟体系,以不同浓度昆仑雪菊醇提物作为抑制剂,研究其对AGEs生成的抑制作用。...为了探讨昆仑雪菊醇提物对美拉德反应晚期糖基化终产物(advanced glycation end products,AGEs)生成的抑制作用,建立乳糖-酪蛋白和葡萄糖-赖氨酸-亚油酸两种模拟体系,以不同浓度昆仑雪菊醇提物作为抑制剂,研究其对AGEs生成的抑制作用。通过分析昆仑雪菊醇提物中总黄酮含量以及反应体系在热处理条件下荧光性AGEs的生成、酪蛋白羰基化程度、赖氨酸相对含量与葡萄糖余量,阐明昆仑雪菊醇提物对AGEs生成的抑制作用程度。结果表明:昆仑雪菊醇提物对AGEs具有显著的抑制作用,0.5 mg/mL醇提物在140℃条件下对AGEs的抑制率可达70.44%;昆仑雪菊醇提物处理后,反应体系中赖氨酸和葡萄糖余量显著高于对照组(P<0.05)。该研究证明,昆仑雪菊醇提物在食品加工过程中能够有效减少AGEs的生成,可为开发食品级的AGEs抑制剂提供数据参考和理论依据,使慢性病患者受益。展开更多
Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reduc...Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reducing the dietary CP level,even supplemented with all amino acids(AAs),detrimentally affects the colonic health,which may be due to the lack of protein-derived peptides.Therefore,this study evaluated the effects of supplementation of casein hydrolysate(peptide source)in low-protein(LP)diets,in comparison with AAs supplementation,on the colonic microbiota,microbial metabolites and mucosal immunity in pigs,aiming to determine whether a supplementation of casein hydrolysate can improve colonic health under very LP level.Twenty-one pigs(initial BW 19.90±1.00 kg,63±1 days of age)were assigned to three groups and fed with control diet(16%CP),LP diets(13%CP)supplemented with free AAs(LPA)or casein hydrolysate(LPC)for 4 weeks.Results:Compared with control diet,LPA and LPC diet decreased the relative abundance of Streptococcus and Escherichia coli,and LPC diet further decreased the relative abundance of Proteobacteria.LPC diet also increased the relative abundance of Lactobacillus reuteri.Both LP diets decreased concentrations of ammonia and cadaverine,and LPC diet also reduced concentrations of putrescine,phenol and indole.Moreover,LPC diet increased total short-chain fatty acid concentration.In comparison with control diet,both LP diets decreased protein expressions of Toll-like receptor-4,nuclear factor-κB,interleukin-1βand tumor necrosis factor-α,and LPC diet further decreased protein expressions of nucleotide-binding oligomerization domain protein-1 and interferon-γ.LPC diet also increased protein expressions of G-protein coupled receptor-43,interleukin-4,transforming growth factor-β,immunoglobulin A and mucin-4,which are indicators for mucosal defense activity.Conclusions:The results showed that supplementing casein hydrolysate showed beneficial effects on the colonic microbiota and mucosal immunity and barrier function in comparison with supplementing free AAs in LP diets.These findings may provide new framework for future nutritional interventions for colon health in pigs.展开更多
There is no study on food-derived peptide with both anticoagulant and angiotensin I-converting enzyme inhibitory (ACEI) activities yet. In this work, the anticoagulant and ACEI activities of the casein hydrolysates re...There is no study on food-derived peptide with both anticoagulant and angiotensin I-converting enzyme inhibitory (ACEI) activities yet. In this work, the anticoagulant and ACEI activities of the casein hydrolysates released by pepsin digestion were evaluated for the first time to the best of our knowledge. Results indicated that the casein hydrolysate exhibited potent anticoagulant activity by prolonging the thrombin time (TT) and the activated partial thromboplastin time (APTT). Compared with control samples, at 10 mg/mL, the TT and APTT of casein hydrolysate were 186.0 % ± 6.6 % and 163.5 % ± 7.4 %, respectively. The casein hydrolysate also showed a strong ACEI activity with an IC50 value of 1.775 mg/mL. The components of the bioactive casein hydrolysate were analyzed by nanoscale liquid chromatography quadrupole time-of-flight tandem mass spectrometry (NanoLC-Q-TOF-MS/MS). Total of 115 peptides were identified, among which 34, 9, 55 and 17 peptides were derived from α_(s1-), α_(s2-), β-, and κ-casein, respectively. The results of PeptideRanker and PepSite 2 analysis showed that 6 peptides (FRQFYQL, NENLLRF, NPWDQVKR, PVVVPPFLQ, PVRGPFPIIV, and ARHPHPHLSF) have both ACEI and anticoagulant activities by binding to the active sites of ACE and thrombin. This study indicated that casein is a potential functional food supplement that can be used for medical purposes.展开更多
The present study here establishes a complete and effective method for isolating,purifying and identifying extracellular and intracellular peptides,and also describes the characters and bioactivities of peptides from ...The present study here establishes a complete and effective method for isolating,purifying and identifying extracellular and intracellular peptides,and also describes the characters and bioactivities of peptides from fermented casein with Lactobacillus helveticus.Intracellular peptides are much larger in quantity and more complex in composition than extracellular peptides,between which the correlation reveals proteolytic and metabolic mechanisms.In addition,totally 241 different peptide sequences were identified by Nano LC–MS/MS from casein(212)and Lactobacillus helveticus proteins(29).These casein-derived peptides mostly originated from-casein,followed byS1-casein,-casein,andS2-casein,and came from extracell(69)and intracell(143),in which common peptides have a total of 27.Forty-four of the identified peptides were previously described as bioactive,including angiotensinconverting enzyme(ACE)-inhibitory,antioxidant,immunomodulating,antimicrobial,DPP-IV inhibitory,antiamnesic and anticancer effects and so on.Thirteen peptides with the potential of some biological activities are obtained,which were described in previous studies.A total of 47 novel peptides of 5 to 26 amino acids that were not disclosed were obtained.The new sources of natural bioactive peptides may have the very high application value as potential new peptide drugs for treatment human diseases.The product peptide DELQDKIHPF found in both extracell and intracell was quantitatively analyzed using the MRM mode of UPLC-U3Q,23.1 and 9.76 ng/mL,respectively.The quantitative analysis of the potential bioactive peptide may also advance the production of peptide products in the future.展开更多
Casein kinase I is a group of ubiquitous Serine/Threonine kinases that have been implicated in both normal cellular functions and several pathological conditions including Alzheimer's disease and cancer.Recent fin...Casein kinase I is a group of ubiquitous Serine/Threonine kinases that have been implicated in both normal cellular functions and several pathological conditions including Alzheimer's disease and cancer.Recent findings in colon and pancreatic cancer have brought tremendous attention to these molecules as potential therapeutic targets in treatment of digestive cancers.In this review,we summarize up to date what is known about this family of kinases and their involvement in carcinogenesis and other pathological conditions.Our emphasis is on their implications in digestive cancers and their potential for cancer screening and therapy.展开更多
Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk p...Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.展开更多
In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal p...In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets. These methods were compared to the nitrogen-free (N-free) diet method. The difference method was based on soy- bean meal as the only protein source, with the experi- mental diets containing crude protein levels at 15% and 20%. The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the pro- tein source, with the experimental diet containing a crude protein level of 17.5%. The N-free diet was prepared with starches and paper fibers. In each meth- od,64 Tianfu meat drakes (7-weeks-old) with an av- erage body weight of 2.77±0.16 kg were used and divided into four groups, and fed four different diets. Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino aciddigestibility, endogenous amino acid loss and true a- mino acid digestibility. The results demonstrated that using the difference, enzyme-hydrolyzed casein and N-free diet methods, endogenous amino acid losses were 0. 9946,1. 2243 and 0. 9297 mg/g dry matter in- take ( DMI), respectively. The true amino acid digest- ibility measured by the difference method was 88.93 %±4.43 %. Using the enzyme-hydrolyzed ca- sein method with two dietary crude protein levels of 15% and 20%, the digestibility was 91.15%±4.33% and 91.97%±4. 16%, respectively, and by the N-free diet methods with two dietary crude protein levels of 15% and 20% ,it was 88.55%±4.29% and 88.82 %±4.61%, respectively. The results suggested that when the dietary protein level was 15% to 20 %, the true amino acid digestibility and endogenous ami- no acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.展开更多
The flocculation of kaolinite colloidal particles was carried out at pH = 6 in suspension of initial turbidity varying between 24 NTU and 102 NTU by a casein extracted from Cocos nucifera cream. During Jar-test essays...The flocculation of kaolinite colloidal particles was carried out at pH = 6 in suspension of initial turbidity varying between 24 NTU and 102 NTU by a casein extracted from Cocos nucifera cream. During Jar-test essays, 90% to 99% of colloids were eliminated in the sediments. The optimal doses of casein used depend on the initial colloids concentrations of the suspension and were found to be 60 mg/L and 100 mg/L respectively for suspensions having turbidity of 24 NTU and 102 NTU. The corresponding residual turbidity are respectively 2.80 NTU and 10.22 NTU for clarified water. The structural analysis of the freeze-dried sediments by FTIR shows sharp adsorption bands at 1558 cm–1 and 1653 cm–1, indicating the presence of casein in the sediment. The flocculation process between the particles of kaolinite and the coconut casein is adsorption and bridging.展开更多
Drying technology of angiotensin converting enzyme (ACE) inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying a...Drying technology of angiotensin converting enzyme (ACE) inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying and freeze drying (P〉0.05). Spay drying was the best drying process for practical industry production. The inlet temperature ranged from 140℃ to 160℃ and the exit temperature ranged from 70 ℃ to 90 ℃ during the spay drying process. Under the optimal conditions, scale-up of angiotensin converted enzyme inhibitory peptide from 1 L to 10 L and the experiment was successively conducted. Peptide yield was 29% and half inhibitory concentration (IC50) was 0.53 g. L^-1.展开更多
High hydrostatic pressure(HHP) processing is applied to a Konjac glucomannan(KGM)-casein(CS) mixture to explore the changes in the mixture's properties and microstructures.The mixture's viscosity increases by ...High hydrostatic pressure(HHP) processing is applied to a Konjac glucomannan(KGM)-casein(CS) mixture to explore the changes in the mixture's properties and microstructures.The mixture's viscosity increases by -18.1% at low HHP(200 MPa) and decreases by about 5.3-31.7% at high HHP(600 MPa).Scanning electron microscopy analysis shows that low HHP induces a denser and more compact structure,and high HHP leads to a porous and reticular structure.X-ray diffraction shows that the mixture is amorphous without dramatic changes; only some small crystalline peaks appear under excessive pressure.Fourier transform infrared analysis indicates that the non-covalent interactions(hydrogen bonds,etc.) are probably the most important factors for the modification of mixture properties.Bonding enhances under low pressure,and weakens with increasing pressure and time.展开更多
The effects of heat treatment(heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy.Heat treatment from 60to 100℃resulted in an increase in th...The effects of heat treatment(heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy.Heat treatment from 60to 100℃resulted in an increase in their fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying activity index,but decreased the size polydispersity of caseins.In the pH range of 5.5to 7.0,the fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying properties decreased with increased heating pH,but the size polydispersity of caseins increased with increased pH.The relationship between the surface fluorescence intensity and emulsifying activity was also investigated,revealing a correlation coefficient of 0.90.These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions.展开更多
Graft copolymerization of casein with acrylonitrile wascarried out using potassium persulfate as an initiator.First,solubility of casein in several solvents was studiedin order to choose a solvent for graft reaction.P...Graft copolymerization of casein with acrylonitrile wascarried out using potassium persulfate as an initiator.First,solubility of casein in several solvents was studiedin order to choose a solvent for graft reaction.Percentgrafting and grafting efficiency under various concentra-tions of initiator and monomer,and various times wereevaluated.A method to separate side chain from graftcopolymer was explored.Side chain length and its distri-bution were investigated.FTIR spectra for side chain,casein,and grafted copolymer were taken to establishthe occurrence of grafting.The thermal property ofgraft copolymer was measured and confirmed that the T_pof the copolymer was improved appreciably.展开更多
Sorafenib,a multikinase inhibitor used for the treatment of hepatocellular carcinoma,is limited by its low oral bioavailability.To overcome this drawback,we have developed novel camel milk casein-derived nanoparticles...Sorafenib,a multikinase inhibitor used for the treatment of hepatocellular carcinoma,is limited by its low oral bioavailability.To overcome this drawback,we have developed novel camel milk casein-derived nanoparticles as a drug delivery system.Camel milk casein is not only biocompatible on oral administration but is actually a dietary protein of pharmaceutical relevance.Casein is used because of its amphiphilic nature,self-assembling property,ability to show sustained release,and capability of encapsulating both hydrophilic and hydrophobic drugs.In this study,camel milk casein nanoparticles loaded with sorafenib were developed and characterized.Characterization of casein nanoparticles was done by dynamic light scattering(DLS),zeta potential analysis,scanning light microscopy(SEM),and FTIR.The drug content in nanoparticle and drug-protein binding studies were conducted by UV spectroscopy.The cytotoxicity and cellular uptake efficiency studies were performed in HepG2 cell lines.It was observed that the cytotoxic effect of sorafenib loaded camel milk casein nanoparticles was more than free sorafenib in HepG2 cells.This work suggests camel milk casein as a suitable drug delivery molecule for sorafenib.In the future,it may also be used in enhancing the efficacy and specific distribution of other water-insoluble anticancer drugs.展开更多
The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteratio...The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteration of Ikaros activity (e.g.haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells.This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia.The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation.Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization.As a consequence,the ability of Ikaros to regulate cell cycle progression,chromatin remodeling,target gene expression,and thymocyte differentiation are controlled by CK2.In addition,hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitinmediated degradation.Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization.Thus,the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor.This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.展开更多
A nutritional intervention for 8 weeks was conducted in the elderly (>65 y) living in nursing homes in Shanghai, who showed body weight within the normal range but albumin levels of <35 g/L. The intervened took ...A nutritional intervention for 8 weeks was conducted in the elderly (>65 y) living in nursing homes in Shanghai, who showed body weight within the normal range but albumin levels of <35 g/L. The intervened took 400 kcal/day of a balanced liquid nutrition formula containing casein as a major protein source (90% of total protein) in addition to their daily diets, while the non-intervened took only daily diets. Daily diet intakes during the trial were 1738 ± 240 kcal/day in the intervened and 1612 ± 187 kcal/day in the non-intervened. The energy intake in the intervened wascompensated for by reducing their daily diets, which resulted in a similar level to that in the non-intervened. This intervention resulted in intakes of protein and carbohydrate being significantly increased: P16.4%, F27.3%, C56.3% in the intervened;P13.0%, F36.3%, C50.7% in the non-intervened. Albumin level of the intervened increased from 32.7 ± 3.1 g/L to 37.3 ± 1.9 g/L, while it did not significantly change in the non-intervened: 30.0 ± 4.2 g/L to 31.3 ± 4.6 g/L. Using GNRI (geriatric nutritional risk index), nutritional risk levels were assessed;GNRI of the intervened significantly improved from 88.7 ± 6.3 (intermediate risk) to 95.7 ± 4.5 (low risk), while its status did not change in the non-intervened: 84.6 ± 7.7 (intermediate risk) to 86.5 ± 7.9 (intermediate risk). The intervention using a casein-based balanced liquid nutrition formula effectively improved protein-malnutrition in the elderly. This result suggests that a casein-based balanced liquid nutrition formula is an effective nutrition source that can be applied to a nutritional program to improve malnutrition of the elderly.展开更多
基金supported by the National Natural Science Foundation of China,Nos.81570849,81100931the Natural Science Foundation of Guangdong Province of China,Nos.2015A030313446,2020A1515011413(all to LPC).
文摘Intraocular pressure elevation can induce retinal ganglion cell death and is a clinically reversible risk factor for glaucoma,the leading cause of irreversible blindness.We previously demonstrated that casein kinase-2 inhibition can promote retinal ganglion cell survival and axonal regeneration in rats after optic nerve injury.To investigate the underlying mechanism,in the current study we increased the intraocular pressure of adult rats to 75 mmHg for 2 hours and then administered a casein kinase-2 inhibitor(4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole)by intravitreal injection.We found that intravitreal injection of 4,5,6,7-tetrabromo-2-azabenzimidazole or 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole promoted retinal ganglion cell survival and reduced the number of infiltrating macrophages.Transcriptomic analysis showed that the mitogen activated protein kinase signaling pathway was involved in the response to intraocular pressure elevation but was not modulated by the casein kinase-2 inhibitors.Furthermore,casein kinase-2 inhibition downregulated the expression of genes(Cck,Htrsa,Nef1,Htrlb,Prph,Chat,Slc18a3,Slc5a7,Scn1b,Crybb2,Tsga10ip,and Vstm21)involved in intraocular pressure elevation.Our data indicate that inhibition of casein kinase-2 can enhance retinal ganglion cell survival in rats after acute intraocular pressure elevation via macrophage inactivation.
文摘Protein colloidal nanoparticles(NPs)are ubiquitous present in nature and function as building blocks with multiple functions in both food formulations and biological processes.Food scientists are inspired by naturally occurring proteins to induce self-assembly behavior of protein by manipulating environmental parameters,providing opportunities to construct special and expected NPs.Zein and casein,the main proteins derived from corn and milk,are two examples of the most prevalently studied food proteins for nanoarchitectures in recent years.In this article,the compositions,structures,and physicochemical properties of these two proteins and casein derivatives are summarized as well as their interactions and characterizations.Strategies to fabricate zein-sodium caseinate based NPs are critically highlighted and illustrated.Particularly,applications such as encapsulation and delivery of bioactive compounds,producing food packaging for enhanced antioxidative and antimicrobial effects,and stabilization of emulsions to achieve fat replacement.Due to the imperative role of food proteins in diet composition,this review not only provides cutting-edge knowledge for nanoparticle construction but also opens new avenues for efficient utilization and exploitation of food proteins.
文摘为了探讨昆仑雪菊醇提物对美拉德反应晚期糖基化终产物(advanced glycation end products,AGEs)生成的抑制作用,建立乳糖-酪蛋白和葡萄糖-赖氨酸-亚油酸两种模拟体系,以不同浓度昆仑雪菊醇提物作为抑制剂,研究其对AGEs生成的抑制作用。通过分析昆仑雪菊醇提物中总黄酮含量以及反应体系在热处理条件下荧光性AGEs的生成、酪蛋白羰基化程度、赖氨酸相对含量与葡萄糖余量,阐明昆仑雪菊醇提物对AGEs生成的抑制作用程度。结果表明:昆仑雪菊醇提物对AGEs具有显著的抑制作用,0.5 mg/mL醇提物在140℃条件下对AGEs的抑制率可达70.44%;昆仑雪菊醇提物处理后,反应体系中赖氨酸和葡萄糖余量显著高于对照组(P<0.05)。该研究证明,昆仑雪菊醇提物在食品加工过程中能够有效减少AGEs的生成,可为开发食品级的AGEs抑制剂提供数据参考和理论依据,使慢性病患者受益。
基金supported by National Key Basic Research Program of China(2013CB127300)Natural Science Foundation of China(31430082).
文摘Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reducing the dietary CP level,even supplemented with all amino acids(AAs),detrimentally affects the colonic health,which may be due to the lack of protein-derived peptides.Therefore,this study evaluated the effects of supplementation of casein hydrolysate(peptide source)in low-protein(LP)diets,in comparison with AAs supplementation,on the colonic microbiota,microbial metabolites and mucosal immunity in pigs,aiming to determine whether a supplementation of casein hydrolysate can improve colonic health under very LP level.Twenty-one pigs(initial BW 19.90±1.00 kg,63±1 days of age)were assigned to three groups and fed with control diet(16%CP),LP diets(13%CP)supplemented with free AAs(LPA)or casein hydrolysate(LPC)for 4 weeks.Results:Compared with control diet,LPA and LPC diet decreased the relative abundance of Streptococcus and Escherichia coli,and LPC diet further decreased the relative abundance of Proteobacteria.LPC diet also increased the relative abundance of Lactobacillus reuteri.Both LP diets decreased concentrations of ammonia and cadaverine,and LPC diet also reduced concentrations of putrescine,phenol and indole.Moreover,LPC diet increased total short-chain fatty acid concentration.In comparison with control diet,both LP diets decreased protein expressions of Toll-like receptor-4,nuclear factor-κB,interleukin-1βand tumor necrosis factor-α,and LPC diet further decreased protein expressions of nucleotide-binding oligomerization domain protein-1 and interferon-γ.LPC diet also increased protein expressions of G-protein coupled receptor-43,interleukin-4,transforming growth factor-β,immunoglobulin A and mucin-4,which are indicators for mucosal defense activity.Conclusions:The results showed that supplementing casein hydrolysate showed beneficial effects on the colonic microbiota and mucosal immunity and barrier function in comparison with supplementing free AAs in LP diets.These findings may provide new framework for future nutritional interventions for colon health in pigs.
基金The China Postdoctoral Science Foundation(2019M661072)the Basic Research Program of Liaoning Education Department(2017J080)the National Natural Science Foundation of China(31771926)funded this study.
文摘There is no study on food-derived peptide with both anticoagulant and angiotensin I-converting enzyme inhibitory (ACEI) activities yet. In this work, the anticoagulant and ACEI activities of the casein hydrolysates released by pepsin digestion were evaluated for the first time to the best of our knowledge. Results indicated that the casein hydrolysate exhibited potent anticoagulant activity by prolonging the thrombin time (TT) and the activated partial thromboplastin time (APTT). Compared with control samples, at 10 mg/mL, the TT and APTT of casein hydrolysate were 186.0 % ± 6.6 % and 163.5 % ± 7.4 %, respectively. The casein hydrolysate also showed a strong ACEI activity with an IC50 value of 1.775 mg/mL. The components of the bioactive casein hydrolysate were analyzed by nanoscale liquid chromatography quadrupole time-of-flight tandem mass spectrometry (NanoLC-Q-TOF-MS/MS). Total of 115 peptides were identified, among which 34, 9, 55 and 17 peptides were derived from α_(s1-), α_(s2-), β-, and κ-casein, respectively. The results of PeptideRanker and PepSite 2 analysis showed that 6 peptides (FRQFYQL, NENLLRF, NPWDQVKR, PVVVPPFLQ, PVRGPFPIIV, and ARHPHPHLSF) have both ACEI and anticoagulant activities by binding to the active sites of ACE and thrombin. This study indicated that casein is a potential functional food supplement that can be used for medical purposes.
文摘The present study here establishes a complete and effective method for isolating,purifying and identifying extracellular and intracellular peptides,and also describes the characters and bioactivities of peptides from fermented casein with Lactobacillus helveticus.Intracellular peptides are much larger in quantity and more complex in composition than extracellular peptides,between which the correlation reveals proteolytic and metabolic mechanisms.In addition,totally 241 different peptide sequences were identified by Nano LC–MS/MS from casein(212)and Lactobacillus helveticus proteins(29).These casein-derived peptides mostly originated from-casein,followed byS1-casein,-casein,andS2-casein,and came from extracell(69)and intracell(143),in which common peptides have a total of 27.Forty-four of the identified peptides were previously described as bioactive,including angiotensinconverting enzyme(ACE)-inhibitory,antioxidant,immunomodulating,antimicrobial,DPP-IV inhibitory,antiamnesic and anticancer effects and so on.Thirteen peptides with the potential of some biological activities are obtained,which were described in previous studies.A total of 47 novel peptides of 5 to 26 amino acids that were not disclosed were obtained.The new sources of natural bioactive peptides may have the very high application value as potential new peptide drugs for treatment human diseases.The product peptide DELQDKIHPF found in both extracell and intracell was quantitatively analyzed using the MRM mode of UPLC-U3Q,23.1 and 9.76 ng/mL,respectively.The quantitative analysis of the potential bioactive peptide may also advance the production of peptide products in the future.
基金Supported by The Merit Review grant (the Department of Veterans Affairs of the United States) and the Grant-in-Aid (the American Heart Association) to Dr. Chai
文摘Casein kinase I is a group of ubiquitous Serine/Threonine kinases that have been implicated in both normal cellular functions and several pathological conditions including Alzheimer's disease and cancer.Recent findings in colon and pancreatic cancer have brought tremendous attention to these molecules as potential therapeutic targets in treatment of digestive cancers.In this review,we summarize up to date what is known about this family of kinases and their involvement in carcinogenesis and other pathological conditions.Our emphasis is on their implications in digestive cancers and their potential for cancer screening and therapy.
基金supported by an earmark fund for the National Key Basic Research Program of China(2011CB100805)
文摘Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.
文摘In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets. These methods were compared to the nitrogen-free (N-free) diet method. The difference method was based on soy- bean meal as the only protein source, with the experi- mental diets containing crude protein levels at 15% and 20%. The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the pro- tein source, with the experimental diet containing a crude protein level of 17.5%. The N-free diet was prepared with starches and paper fibers. In each meth- od,64 Tianfu meat drakes (7-weeks-old) with an av- erage body weight of 2.77±0.16 kg were used and divided into four groups, and fed four different diets. Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino aciddigestibility, endogenous amino acid loss and true a- mino acid digestibility. The results demonstrated that using the difference, enzyme-hydrolyzed casein and N-free diet methods, endogenous amino acid losses were 0. 9946,1. 2243 and 0. 9297 mg/g dry matter in- take ( DMI), respectively. The true amino acid digest- ibility measured by the difference method was 88.93 %±4.43 %. Using the enzyme-hydrolyzed ca- sein method with two dietary crude protein levels of 15% and 20%, the digestibility was 91.15%±4.33% and 91.97%±4. 16%, respectively, and by the N-free diet methods with two dietary crude protein levels of 15% and 20% ,it was 88.55%±4.29% and 88.82 %±4.61%, respectively. The results suggested that when the dietary protein level was 15% to 20 %, the true amino acid digestibility and endogenous ami- no acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.
文摘The flocculation of kaolinite colloidal particles was carried out at pH = 6 in suspension of initial turbidity varying between 24 NTU and 102 NTU by a casein extracted from Cocos nucifera cream. During Jar-test essays, 90% to 99% of colloids were eliminated in the sediments. The optimal doses of casein used depend on the initial colloids concentrations of the suspension and were found to be 60 mg/L and 100 mg/L respectively for suspensions having turbidity of 24 NTU and 102 NTU. The corresponding residual turbidity are respectively 2.80 NTU and 10.22 NTU for clarified water. The structural analysis of the freeze-dried sediments by FTIR shows sharp adsorption bands at 1558 cm–1 and 1653 cm–1, indicating the presence of casein in the sediment. The flocculation process between the particles of kaolinite and the coconut casein is adsorption and bridging.
基金Supported by Scientific Research Foundation for Young Scholars of Heilongjiang Province of China (QC07C25)The National High Technology Research and Development Program of China (2008AA10Z315)
文摘Drying technology of angiotensin converting enzyme (ACE) inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying and freeze drying (P〉0.05). Spay drying was the best drying process for practical industry production. The inlet temperature ranged from 140℃ to 160℃ and the exit temperature ranged from 70 ℃ to 90 ℃ during the spay drying process. Under the optimal conditions, scale-up of angiotensin converted enzyme inhibitory peptide from 1 L to 10 L and the experiment was successively conducted. Peptide yield was 29% and half inhibitory concentration (IC50) was 0.53 g. L^-1.
基金Supported by China Postdoctoral Science Foundation(No.2014M551502)National Natural Science Foundation of China(No.31301599)
文摘High hydrostatic pressure(HHP) processing is applied to a Konjac glucomannan(KGM)-casein(CS) mixture to explore the changes in the mixture's properties and microstructures.The mixture's viscosity increases by -18.1% at low HHP(200 MPa) and decreases by about 5.3-31.7% at high HHP(600 MPa).Scanning electron microscopy analysis shows that low HHP induces a denser and more compact structure,and high HHP leads to a porous and reticular structure.X-ray diffraction shows that the mixture is amorphous without dramatic changes; only some small crystalline peaks appear under excessive pressure.Fourier transform infrared analysis indicates that the non-covalent interactions(hydrogen bonds,etc.) are probably the most important factors for the modification of mixture properties.Bonding enhances under low pressure,and weakens with increasing pressure and time.
基金International Science&Technology Cooperation Program of China(2011DFA32550)Ministry of Science and Technology of China(2012BAD12B08)
文摘The effects of heat treatment(heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy.Heat treatment from 60to 100℃resulted in an increase in their fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying activity index,but decreased the size polydispersity of caseins.In the pH range of 5.5to 7.0,the fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying properties decreased with increased heating pH,but the size polydispersity of caseins increased with increased pH.The relationship between the surface fluorescence intensity and emulsifying activity was also investigated,revealing a correlation coefficient of 0.90.These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions.
文摘Graft copolymerization of casein with acrylonitrile wascarried out using potassium persulfate as an initiator.First,solubility of casein in several solvents was studiedin order to choose a solvent for graft reaction.Percentgrafting and grafting efficiency under various concentra-tions of initiator and monomer,and various times wereevaluated.A method to separate side chain from graftcopolymer was explored.Side chain length and its distri-bution were investigated.FTIR spectra for side chain,casein,and grafted copolymer were taken to establishthe occurrence of grafting.The thermal property ofgraft copolymer was measured and confirmed that the T_pof the copolymer was improved appreciably.
文摘Sorafenib,a multikinase inhibitor used for the treatment of hepatocellular carcinoma,is limited by its low oral bioavailability.To overcome this drawback,we have developed novel camel milk casein-derived nanoparticles as a drug delivery system.Camel milk casein is not only biocompatible on oral administration but is actually a dietary protein of pharmaceutical relevance.Casein is used because of its amphiphilic nature,self-assembling property,ability to show sustained release,and capability of encapsulating both hydrophilic and hydrophobic drugs.In this study,camel milk casein nanoparticles loaded with sorafenib were developed and characterized.Characterization of casein nanoparticles was done by dynamic light scattering(DLS),zeta potential analysis,scanning light microscopy(SEM),and FTIR.The drug content in nanoparticle and drug-protein binding studies were conducted by UV spectroscopy.The cytotoxicity and cellular uptake efficiency studies were performed in HepG2 cell lines.It was observed that the cytotoxic effect of sorafenib loaded camel milk casein nanoparticles was more than free sorafenib in HepG2 cells.This work suggests camel milk casein as a suitable drug delivery molecule for sorafenib.In the future,it may also be used in enhancing the efficacy and specific distribution of other water-insoluble anticancer drugs.
基金Supported by (in part) An NIH R01 HL095120 grant,a St.Baldrick’s Foundation Career Development Award,the Four Diamonds Fund of the Pennsylvania State University College of Medicine,and the John Wawrynovic Leukemia Research Scholar Endowment (SD)
文摘The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteration of Ikaros activity (e.g.haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells.This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia.The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation.Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization.As a consequence,the ability of Ikaros to regulate cell cycle progression,chromatin remodeling,target gene expression,and thymocyte differentiation are controlled by CK2.In addition,hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitinmediated degradation.Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization.Thus,the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor.This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.
文摘A nutritional intervention for 8 weeks was conducted in the elderly (>65 y) living in nursing homes in Shanghai, who showed body weight within the normal range but albumin levels of <35 g/L. The intervened took 400 kcal/day of a balanced liquid nutrition formula containing casein as a major protein source (90% of total protein) in addition to their daily diets, while the non-intervened took only daily diets. Daily diet intakes during the trial were 1738 ± 240 kcal/day in the intervened and 1612 ± 187 kcal/day in the non-intervened. The energy intake in the intervened wascompensated for by reducing their daily diets, which resulted in a similar level to that in the non-intervened. This intervention resulted in intakes of protein and carbohydrate being significantly increased: P16.4%, F27.3%, C56.3% in the intervened;P13.0%, F36.3%, C50.7% in the non-intervened. Albumin level of the intervened increased from 32.7 ± 3.1 g/L to 37.3 ± 1.9 g/L, while it did not significantly change in the non-intervened: 30.0 ± 4.2 g/L to 31.3 ± 4.6 g/L. Using GNRI (geriatric nutritional risk index), nutritional risk levels were assessed;GNRI of the intervened significantly improved from 88.7 ± 6.3 (intermediate risk) to 95.7 ± 4.5 (low risk), while its status did not change in the non-intervened: 84.6 ± 7.7 (intermediate risk) to 86.5 ± 7.9 (intermediate risk). The intervention using a casein-based balanced liquid nutrition formula effectively improved protein-malnutrition in the elderly. This result suggests that a casein-based balanced liquid nutrition formula is an effective nutrition source that can be applied to a nutritional program to improve malnutrition of the elderly.