Determination of free amino acids in burley tobacco by high performance liquid chromatography

A reversed-phase high performance liquid chromatographic method was developed for determining free amino acids in burley tobacco. The test was done by OPA/3-mercaptopropionic acid as the pre-column derivatizing reagent. Chromatographic column was Elitte C¹⁸ column (4.6 mm × 250 mm i.d., 5 μm). Mobile phase A was 18 mol/l NaAc (pH7.2) including 0.002%(v/v) triethylamine and 0.3%(v/v) furanidine. Mobile phase B was 100 mol/l NaAc (pH7.2)–acetonitrile–methanol (v/v = 1:2:2). The column temperature was 40 °C and the flow rate was 1.0 ml/min. The fluorescence detector was used with 350 nm excitation wave length and 450 nm emission wave length. The average recoveries of the method ranged from 95.3–100.7% with the relative standard deviation of 2.32–9.24%. The method is simple, accurate and has good repeatability. The results of the determination of seventeen kinds of free amino acids in burley leaves were produced by the way of different ratios of cake fertilizer and inorganic fertilizer. The results show that Aspartic acid has the highest content however ratio of cake fertilizer and inorganic fertilizer. The contents of most of the free amino acids are increased and then gradually decreased with the increase in organic manure. The contents of most of the free amino acids are very close at 15:85% ratio and 30:70% ratio of cake fertilizer and inorganic fertilizer. The total amount of free amino acids is the highest at 30:70% ratio of cake fertilizer and inorganic fertilizer. Considering comprehensively, the quality of burley leaves is the best at 30:70% ratio of cake fertilizer and inorganic fertilizer.     

A novel enzyme from bovine neurointermediate pituitary catalyzes dealkylation of alpha-hydroxyglycine derivatives, thereby functioning sequentially with peptidylglycine alpha-amidating monooxygenase in peptide amidation

We report here the isolation of a novel enzyme from bovine neurointermediate pituitary which catalyzes the conversion of alpha-hydroxybenzoylglycine to benzamide. This enzyme, termed HGAD (alpha-hydroxyglycine amidating dealkylase), is a soluble protein with an apparent molecular mass of 45 kDa and no apparent cofactor requirement. Addition of HGAD to purified neurointermediate pituitary PAM (peptidylglycine alpha-amidating monooxygenase, EC 1.14.17.3) increases the rate of formation of amide products by an order of magnitude. Sequential additions of PAM and HGAD gave results consistent with PAM first catalyzing the formation of an intermediate that is subsequently, in a separate reaction, converted by HGAD to the final amide product. Experiments with olefinic inactivators demonstrate that HGAD is not required for turnover-dependent inactivation of PAM and, correspondingly, that HGAD activity is not affected by inactivators of PAM. As expected, HGAD has no effect on the rate of PAM-catalyzed sulfoxidation, where a reaction analogous to that occurring during amidation of glycine-extended substrates is not possible. On the basis of these results, we propose that peptide C-terminal amidation in neurointermediate pituitary is a two-step process, with PAM first catalyzing the conversion of a glycine-extended peptide to the alpha-hydroxyglycine derivative, which is in turn converted to the final amide product by HGAD.     

Pre-cold acclimation promotes cryoprotectant accumulation and enhances freezing tolerance of Meloidogyne incognita

Strong evidence suggests that cryoprotectant accumulation during pre-cold acclimation protects cells against freezing injuries caused by cellular dehydration. In this study, the concentrations of trehalose and glycerol were measured in Meloidogyne incognita and it was found that both cryoprotectants were significantly accumulated in second-stage juveniles (J2) of M. incognita after acclimation at 4°C. However, compared with non-acclimated samples, only a higher level of trehalose was induced in the egg masses of M. incognita in response to cold treatment. Further characterizations indicated that pre-cold acclimation efficiently accelerated the speed of larvae hatching from egg masses that were subjected to freezing at −1°C. In addition, the survival rate and pathogenicity of M. incognita J2 that had been acclimated prior to freezing were significantly enhanced when compared with non-acclimated J2 individuals. As far as we know, this is the first time that this phenomenon has been reported in M. incognita.     

Ecology of Hantaan virus at Twin Bridges Training Area,Gyeonggi Province,Republic of Korea, 2005–2007

The Twin Bridges Training Area (TBTA) in the Republic of Korea consists of dirt roads, barren training areas, and forested hillsides adjacent to linear and broad expanses of tall grasses, herbaceous, and scrub vegetation. Of the six species of small mammals, the striped field mouse, Apodemus agrarius, was the most frequently captured (96.1%). Apodemus agrarius capture rates varied from 17.7 to 33.2% during three trapping periods. Gravid females were observed during November‐December 2006 (8.4%) and March 2007 (5.1%). In 2005, the overall seroprevalence of Hantaan virus (HTNV) was high (34.4%) and lower during surveys in 2006 (14.2%) and 2007 (13.8%). Seroprevalence was directly correlated with weight increase of A. agrarius.     

A water channel of the nematode C.elegans and its implications for channel selectivity of MIP proteins

A genome project focusingon the nematode Caenorhabditis elegans has demonstrated thepresence of eight cDNAs belonging to the major intrinsic proteinsuperfamily. We functionally characterized one of these cDNAs namedC01G6.1. Injection of C01G6.1 cRNA increased the osmotic waterpermeability (P_f) of Xenopusoocytes 11-fold and the urea permeability 4.5-fold but failed toincrease the glycerol permeability. It has been speculated that the MIPfamily may be separated into two large subfamilies based on thepresence or absence of two segments of extra amino acid residues (~15amino acids) at the second and third extracellular loops. BecauseC01G6.1 (designated AQP-CE1), AQP3, and glycerol facilitator (GlpF) all have these two segments, we replaced the segments of AQP-CE1 with thoseof AQP3 and GlpF to identify their roles. The functional characteristics of these mutants were principally similar to that ofwild-type AQP-CE1, although the values of P_f andurea permeability were decreased by 39-74% and 28-65%,respectively. These results suggest that the two segments of extraamino acid residues may not contribute to channel selectivity orformation of the route for small solutes.