A Novel Exponential Kinetic Model for Casein Tryptic Hydrolysis to Prepare Active Peptides

The kinetics of casein tryptic hydrolysis to prepare activepeptides was investigated. Taking into account the reaction mechanismincluding single substrate hydrolysis, irreversible enzymeinactivation, and substrate inhibition, a set of exponentialequations was established to characterize the enzymatic hydrolysiscurves. The verification was carried out by a series of experimentalresults and indicated that the average regressive error was less than5/100. According to the proposed kinetic model, the kinetic constantsand thermodynamic constants of the reaction system were alsocalculated.

Antiviral active peptide from oyster

An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster(Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin.The hydrolysate was fractioned into four ranges of molecular weight(>10 kDa,10-5 kDa,5-1 kDa and <1 kDa) using ultrafiltration membranes and dialysis.The fraction of 10-5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column,Sephadex G-25 column,and high performance liquid chromatogram(HPLC) by activity-guided isolation.The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect(CPE).The result shows that the peptide has high inhibitory activity on herpetic virus.

Effects of Soybean Active Peptides on Performance and Serum Lipid of 14-day Old Early Weaned Piglets

This purpose was to evaluate the efficacy of soybean active peptides (SAP) in 14-day old early weaned piglets feed. Eighteen crossbreed piglets Duroc ×Landrace ×Yorkshire (14-day old) were randomly divided into three groups with six piglets each group. Control was fed with 8% animal plasma (AP). Trial 1 was fed with 4.9% AP and 4.9% SAP. Trial 2 was fed with 12.62% SAP. This raising period was 30 days and divided into three periods with earlier period (0-15 days), latter period (16-30 days) and whole period (0-30 days). The results showed that average daily gains (ADG) in trial 1 were increased 16.33%, 12.64% and 13.94% (P >0.05) and Efficiency of feed conversions (EFC) improved 17.35%, 11.40% and 13.46% than control in respective periods; ADG in trial 2 were reduced 12.24%, increased 4.21% and reduced 0.40% (P>0.05) and EFC were improved 19.81%, 13.08% and 15.76% than control in respective periods. Means of TG and LDL-C/ HDL-C in trial 1 were lowest in three groups and reduced 6.54% (P >0.05) and 0.96% than control. Means of TG, TC, LDL-C, HDL-C, LDL-C/ HDL-C were the highest in trial 2 among three groups and increased 8.93% (P >0.05), 39.69% (P <0.05), 34.94% (P >0.05), 27.31% (P >0.05) and 5.96% than control respectively. It was concluded that substituting part Ap for SAP in 14-day old piglets Feed was practicable.

Mechanism of annexin A1/N-formylpeptide receptor regulation of macrophage function to inhibit hepatic stellate cell activation through Wnt/β-catenin pathway

BACKGROUND Hepatic fibrosis is a common pathological process of chronic liver diseases with various causes,which can progress to cirrhosis.AIM To evaluate the effect and mechanism of action annexin(Anx)A1 in liver fibrosis and how this could be targeted therapeutically.METHODS CCl4(20%)and active N-terminal peptide of AnxA1(Ac2-26)and N-formylpeptide receptor antagonist N-Boc-Phe-Leu-Phe-Leu-Phe(Boc2)were injected intraperitoneally to induce liver fibrosis in eight wild-type mice/Anxa1 knockout mice,and to detect expression of inflammatory factors,collagen deposition,and the role of the Wnt/β-catenin pathway in hepatic fibrosis.RESULTS Compared with the control group,AnxA1,transforming growth factor(TGF)-β1,interleukin(IL)-1βand IL-6 expression in the liver of mice with hepatic fibrosis induced by CCl4 was significantly increased,which promoted collagen deposition and expression ofα-smooth muscle actin(α-SMA),collagen type I and connective tissue growth factor(CTGF),and increased progressively with time.CCl4 induced an increase in TGF-β1,IL-1βand IL-6 in liver tissue of AnxA1 knockout mice,and the degree of liver inflammation and fibrosis and expression ofα-SMA,collagen I and CTGF were significantly increased compared with in wild-type mice.After treatment with Ac2-26,expression of liver inflammatory factors,degree of collagen deposition and expression of a-SMA,collagen I and CTGF were decreased compared with before treatment.Boc2 inhibited the anti-inflammatory and antifibrotic effects of Ac2-26.AnxA1 downregulated expression of the Wnt/β-catenin pathway in CCl4-induced hepatic fibrosis.In vitro,lipopolysaccharide(LPS)induced hepatocyte and hepatic stellate cell(HSC)expression of AnxA1.Ac2-26 inhibited LPS-induced RAW264.7 cell activation and HSC proliferation,decreased expression ofα-SMA,collagen I and CTGF in HSCs,and inhibited expression of the Wnt/β-catenin pathway after HSC activation.These therapeutic effects were inhibited by Boc2.CONCLUSION AnxA1 inhibited liver fibrosis in mice,and its mechanism may be related to inhibition of HSC Wnt/β-catenin pathway activation by targeting formylpeptide receptors to regulate macrophage function.

Clinical value of rapid urine trypsinogen-2 test strip, urinary trypsinogen activation peptide, and serum and urinary activation peptide of carboxypeptidase B in acute pancreatitis

AIM: To assess the usefulness of urinary trypsinogen-2 test strip, urinary trypsinogen activation peptide (TAP),and serum and urine concentrations of the activation peptide of carboxypeptidase B (CAPAP) in the diagnosisof acute pancreatitis.METHODS: Patients with acute abdominal pain and hospitalized within 24 h after the onset of symptoms were prospectively studied. Urinary trypsinogen-2 was considered positive when a clear blue line was observed (detection limit 50 μg/L). Urinary TAP was measured using a quantitative solid-phase ELISA, and serum and urinary CAPAP by a radioimmunoassay method.RESULTS: Acute abdominal pain was due to acute pancreatitis in 50 patients and turned out to be extrapancreatic in origin in 22 patients. Patients with acute pancreatitis showed significantly higher median levels of serum and urinary CAPAP levels, as well as amylase and lipase than extrapancreatic controls. Median TAP levels were similar in both groups. The urinary trypsinogen-2 test strip was positive in 68% of patients with acute pancreatitis and 13.6% in extrapancreatic controls (P<0.01). Urinary CAPAP was the most reliable test for the diagnosis of acute pancreatitis (sensitivity 66.7%, specificity 95.5%, positive and negative predictive values 96.6% and 56.7%, respectively), with a 14.6 positive likelihood ratio for a cut-off value of 2.32 nmol/L.CONCLUSION: In patients with acute abdominal pain,hospitalized within 24 h of symptom onset, CAPAP in serum and urine was a reliable diagnostic marker of acute pancreatitis. Urinary trypsinogen-2 test strip showed a clinical value similar to amylase and lipase.Urinary TAP was not a useful screening test for the diagnosis of acute pancreatitis.

Prediction of the severity of acute pancreatitis on admission by urinary trypsinogen activation peptide: A meta-analysis

AIM: To undertake a meta-analysis on the value of urinary trypsinogen activation peptide (uTAP) in predicting severity of acute pancreatitis on admission.METHODS: Major databases including Medline, Embase, Science Citation Index Expanded and the Cochrane Central Register of Controlled Trials in the Cochrane Library were searched to identify all relevant studies from January 1990 to January 2013. Pooled sensitivity, specificity and the diagnostic odds ratios (DORs) with 95%CI were calculated for each study and were compared to other systems/biomarkers if mentioned within the same study. Summary receiver-operating curves were conducted and the area under the curve (AUC) was evaluated.RESULTS: In total, six studies of uTAP with a cut-off value of 35 nmol/L were included in this meta-analysis. Overall, the pooled sensitivity and specificity of uTAP for predicting severity of acute pancreatitis, at time of admission, was 71% and 75%, respectively (AUC = 0.83, DOR = 8.67, 95%CI: 3.70-20.33). When uTAP was compared with plasma C-reactive protein, the pooled sensitivity, specificity, AUC and DOR were 0.64 vs 0.67, 0.77 vs 0.75, 0.82 vs 0.79 and 6.27 vs 6.32, respectively. Similarly, the pooled sensitivity, specificity, AUC and DOR of uTAP vs Acute Physiology and Chronic Health Evaluation II within the first 48 h of admission were found to be 0.64 vs 0.69, 0.77 vs 0.61, 0.82 vs 0.73 and 6.27 vs 4.61, respectively.CONCLUSION: uTAP has the potential to act as a stratification marker on admission for differentiating disease severity of acute pancreatitis.

The effect of tailing lipidation on the bioactivity of antimicrobial peptides and their aggregation tendency Special Issue:Emerging Investigators

Antimicrobial peptides(AMPs)are potentially powerful alternatives to conven-tional antibiotics in combating multidrug resistance,given their broad spectrum of activity.They mainly interact with cell membranes through surface electrostatic potentials and the formation of secondary structures,resulting in permeability and destruction of target microorganism membranes.Our earlier work showed that two leading AMPs,MSI-78(4–20)and pardaxin(1–22),had potent antimicrobial activ-ity against a range of bacteria.It is known that the attachment of moderate-length lipid carbon chains to cationic peptides can further improve the functionality of these peptides through enhanced interactions with the membrane lipid bilayer,inducing membrane curvature,destabilization,and potential leakage.Thus,in this work,we aimed to investigate the antimicrobial activity,oligomerization propensity,and lipid-membrane binding interactions of a range of N-terminal lipidated analogs of MSI-78(4–20)and pardaxin(1–22).Molecular modeling results suggest that aggregation of the N-lipidated AMPs may impart greater structural stability to the peptides in solu-tion and a greater depth of lipid bilayer insertion for the N-lipidated AMPs over the parental peptide.Our experimental and computationalfindings provide insights into how N-terminal lipidation of AMPs may alter their conformations,with subsequent effects on their functional properties in regard to their self-aggregation behavior,membrane interactions,and antimicrobial activity.

Effect of Volatile Oil of Amomum on Expressions of Platelet Activating Factor and Mastocarcinoma-related Peptide in the Gastric Membrane of Chronic Gastritis Patients with Helicobacter-pylori Infection

Objective： To observe the effect of volatile oil of amomum （VOA） on the expressions of mastocarcinoma-related peptide （PS2） and platelet activating factor （PAF） in helicobacter pylori- associated gastritis （HPG） and to analyze its potential mechanism. Methods： Eighty patients with HPG were randomly assigned to two groups, 42 patients in the treated group treated with 0.5 mL VOA, thrice per day; and the 38 patients in the control group receiving Western tertiary medicinal treatment. Gastroscopic picture and helicobacter pylori （HP） infection （by quick urease and Warthin- Starry stain） of the gastro-membrane, expressions of PS2 and PAF （by immunohistochemical assay and Western blotting） as well as the contents of aminohexose and phospholipid （by Neuhaus method） in the gastric membrane of all patients were detected before treatment and 4 weeks after treatment. The clinical efficacy in the two groups was compared. Results： The total effective rate in the treated group was 88.1%, which was significantly higher than that in the control group （78.9%, P〈0.05）. After treatment, in the treated group, gastric membranous contents of aminohexose and phospholipid was increased, expression of PS2 elevated but that of PAF lowered, all showing significant difference as compared with those in the control group （P〈0.01）. In the control group, the expressions of PS2 and PAF changed insignificantly. The radical eliminating rate of HP in the treated group and the control group was insignificantly different between them （76.1% vs. 65.8%, P 〉 0.05）. Conclusion： The mechanism of VOA for anti-gastritis might be related with its action in increasing the expression of PS2 and decreasing the expression of PAF, and thus regulating the hydrophobicity of the gastric membrane.

Chemical synthesis of Ub-AMC via ligation of peptide hydrazides

The C-terminal conjugate of ubiquitin with 7-amino-4-methylcoumarin （Ub-AMC） is an important probe for fluorescencebased analysis of deubiquitinating enzyme （DUB） activity. It is important to develop more efficient methods for the preparation of Ub-AMC because the currently available technology is still expensive for scaled-up production. In the present work we report an efficient strategy for total chemical synthesis of Ub-AMC through ligation of peptide hydrazides. Three peptide segments are assembled via N-to-C sequential ligation and the resulting product is converted to Ub-AMC via TCEP-mediated desulfurization. The synthetic Ub-AMC is shown to have expected biological functions throug

基于PACAP-cAMP信号通路研究电针治疗骶上脊髓损伤后逼尿肌反射亢进型膀胱的效应机制

Objective:To elucidate the underlying mechanism and effect of electroacupuncture(EA)on the neurogenic bladder following suprasacral spinal cord injury(ssCI).A rat model of detrusor hyperreflexia after SsCI was established to examine the urodynamics,detrusor muscle tissue morphology,the protein and mRNA expression levels of pituitary adenylate cyclase activating peptide(PACAP)and its receptor PAC1R,and cyclic adenosine monophosphate(cAMP)content in the detrusor muscle with a focus on the PACAPcAMP signaling pathway.Method:A total of 72 female SD rats were randomized into control group and sham operation group(n=12 per group)by using a random number table.The remaining 48 rats were established into the model of detrusor hyperreflexia after SsCI.After successful modeling,these rats were randomly assigned to model,EA,and EA+PACAP6-38 groups(n=12 per group).The unsuccessful modeled rats were used for exploratory observation.For the rats in EA group,"Ciliao(BL32)""Zhongji(CV3)",and"Sanyinjiao(SP6)"were needled and stimulated by EA.The PACAP receptor antagonist PACAP6-38 was administered intraperitoneally in the EA+PACAP6-38 group before EA,and EA was applied for seven consecutive days.After treatment,the urodynamics of the rats were analyzed,and hematoxylin and eosin staining was used to examine rat bladder detrusor tissue morphology.The expressions of PACAP-38 and PAC1R were detected by immunohistochemistry and Western blot.The mRNA expression levels of PACAP-38 and PAC1R were examined by RT-qPCR,while cAMP content was detected by ELISA.Results:(1)Compared with sham operation group,it was exhibited disarray in the transitional epithelium cells of the bladder in the modeled rats.The intercellular space was significantly widened,accompanied by inflammatory cell infiltration and noticeable tissue edema.Both the bladder initial pressure and leak point pressure of the rats were higher(P<0.01),whereas the maximum cystometric capacity and bladder compliance were lower(P<0.01).The protein and mRNA expression levels of PACAP-38 and PAC1R in the detrusor muscle,together with the cAMP content,were lower(P<0.05).(2)Compared with the model rats,the EA group showed reduced inflammatory response in the detrusor muscle tissue,with decreased monocyte infiltration and less severe tissue edema.The bladder smooth muscle cells exhibited increased integrity,and there was decreased cellular tissue edema,inflammatory cell infiltration,and fibroplasia.The bladder initial pressure and leak point pressure were lower(P<0.05),while the maximum cystometric capacity and bladder compliance were higher(P<0.01).The protein and mRNA expression levels of PACAP-38 and PAC1R in the detrusor muscle,along with the cAMP content,were higher(P<0.05).(3)Compared to the EA group,the EA+PACAP6-38 group showed a less organized arrangement of muscle fibers in the detrusor muscle tissue,larger intercellular space,monocyte infltration,and considerable tissue edema.The changes in bladder initial pressure and leak point pressure were not significant(P>0.05),while the maximum cystometric capacity and bladder compliance were lower(P<0.05).The changes in the protein and mRNA expressions of PACAP-38 within the detrusor muscle were not signifcant(P>0.05),whereas the protein and mRNA expressions of PAC1R were reduced(P<0.05),and the cAMP content within the detrusor muscle was lower(P<0.05).Conclusion:EA can ameliorate the uninhibited contractile condition of the detrusor muscle in the bladder following SSCI.By mediating the PACAP-cAMP signaling pathway,it reduces the pathological damage to the detrusor muscle,thereby improving bladder function.