Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

STUDY ON THE MECHANISM OF INTERFERON ACTION (Ⅺ)——EFFECT OF pppA2'p5'A2'p5'A ON THE LEVEL OF cAMP AND cGMP IN MACROPHAGES

In this paper, the increase of cellular cAMP and cGMP levels in macrophages induced bypppA2'p5'A2'p5'A (briefly 2'-5'P_3A_3) is first reported. The optimal concentration of 2'-5'P_3A_3 for the elevation of cellular cGMP to the highest level is 10^(-7)-10^(-6)mol/L, while thatfor cAMP is 10^(-7)mol/L. The time for cGMP to reach its peak value is 15 min and that forcAMP is 2 h, when the cells are treated with 2'-5' P_3A_3 at 10^(-7)mol/L, which is the optimalconcentration for developing biological effect of macrophages (phagocytosis). These resultssuggest that cGMP and cAMP may be related to, or may be the mediators for, 2'-5'P_3A_3action.

Meat quality traits of four Chinese indigenous chicken breeds and one commercial broiler stock

Meat quality traits of four genotypes of Chinese indigenous chicken [Ninghai chicken(NC),frizzle chicken(FC),Ninghai xiang chicken(XC),and Zhenning loquat chicken(LC)] and one genotype of commercial broiler [Arbor Acres plus broiler(AAB)] were analyzed.The indigenous chickens were raised before the commercial chickens in order to achieve the same final processed days.Indigenous chickens of NC,FC,XC,and LC showed significantly higher inosine-5′-monophosphate(IMP) content,shorter fiber diameter,and lower shear force than those of AAB(P<0.05).In the indigenous genotypes,NC and FC had significantly shorter fiber diameters and lower shear forces than XC and LC(P<0.05),and NC and XC had a higher IMP content than FC and LC(P<0.05).Moreover,the indigenous genotype of LC significantly displayed the highest protein content(P<0.05) in the five genotypes of birds,and no significant differences of protein content were found between the other genotypes of NC,FC,XC,and AAB(P>0.05).The indigenous chickens from FC displayed the highest total lipid content in the five bird genotypes(P<0.05).Significant differences of pH,color values of L* and a*,and drip loss for the five genotypes of birds were also observed.In conclusion,there were significant differences in the meat quality traits of the bird breeds selected in this study,and the indigenous chickens,especially the NC genotype,produced better quality meat as far as the IMP content,fiber diameters,and shear forces were concerned.

Effects of catecholamine-β-adrenoceptor-cAMP system on severe patients with heart failure

Objective To investigate the association between catecholamine-β-adrenoceptor (β-AR)-adenosine 3’,5’-monophosphate (cAMP) system and long-term prognosis in patients with chronic heart failure (CHF).Methods The study population comprised 73 patients with CHF (EF: 23%±10%) with a mean follow-up of 3.8±1.9 years. Plasma levels of norepinephrine (NE) were measured using high performance lipid chromatography,β-adrenergic receptor density (Bmax) and the content of cAMP in peripheral lymphocytes were calculated using 3H-dihydroalpneolo as ligand and competitive immunoassay,respectively. Deaths due to cardiovascular events within the follow-up period were registered.Results The total mortality was 64.7%,57.4% of which was for cardiogenic (worsening heart failure: 32.4%; sudden death: 25.0%). In the cardiogenic death group,plasma levels of NE and epinephrine (E) (3.74 nmol/L±0.09 nmol/L and 3.17 nmol/L±1.0nmol/L) and the contents of peripheral lymphocyte cAMP (3.64 pmol/mg protein±1.4 pmol/mg protein) were significantly increased as compared with the survival group (2.68 nmol/L±0.07 nmol/L,2.41 nmol/L±0.24 nmol/L and 2.73 pmol/mg protein±0.9 pmol/mg protein,respectively,all P <0.01). In the sudden death group,plasma levels of NE and E (5.01 nmol/L±0.06 nmol/L and 4.13 nmol/L±0.08 nmol/L) were significantly increased as compared with the worsening heart failure group (2.49 nmol/L±0.07 nmol/L and 2.33 nmol/L±0.8 nmol/L,all P <0.001) and to the survival group (2.68 nmol/L±0.07 nmol/L and 2.41 nmol/L±0.14 nmol/L,all P <0.01). The incidences of sudden death were 0%,75%,and 100% (χ 2=16.018, P <0.01) in patients with plasma NE<2.5 nmol/L,NE 2.5 nmol/L-4.5 nmol/L,and NE>4.5 nmol/L,respectively. In the worsening heart failure group,the content of peripheral lymphocyte cAMP (4.46 pmol/mg protein±0.18 pmol/mg protein) was significantly increased compared with the sudden death group (2.39 pmol/mg protein±0.9 pmol/mg protein,P <0.001) and to the survival group (2.73 pmol/mg protein±1.1 pmol/mg protein,P <0.001). The worsening heart failure death occurences were 5.0%,72.2%,and 100% (χ 2=14.26,P <0.01) in patients with a content of peripheral lymphocyte cAMP <2.5 nmol/L,cAMP 2.5 nmol/L-4.5 nmol/L,and cAMP>4.5nmol/L,respectively. B max in peripheral lymphocyte was not significantly different ( P >0.05) among the sudden death,worsening heart failure,and survival groups in CHF patients.Conclusions Plasma levels of catecholamine increase significantly,and B max and the contents of cAMP in peripheral lymphocytes decrease significantly in patients with CHF. High plasma catecholamine levels may be associated with sudden death,and high intralymphocyte cAMP content may be associated with worsening heart failure in CHF patients.