N-叔丁氧酰基-O-烷基-L-酪氨酸甲酯的合成工艺研究

以L-酪氨酸为原料,经由羧基、氨基保护后,对其侧链酚羟基进行修饰,得到两个未见文献报道酪氨酸的衍生物Ia,Ib,其总收率分别为74.5%,75.6%,合成方法简便,成本低廉,具有较高的商业应用价值.化合物结构经MS,IR,1H NMR和13C NMR的验证.

Abstract：

The carboxyl and amino groups of L-tyrosine were protected with methyl esterification for the carboxyl group and with tert-butyloxy carbonylation for the amino group, and then the hydroxyl group was alkylated with n-butyl bromide and methyl-bromoacetate alternatively. Thus two new L-tyrosine derivatives (Ia and Ib) were obtained with an overall yield 74.5% and 75.6%, respectively. The established synthesis technology of L-tyrosine derivatives has advantages over other known ways for its facile operation and low cost. Therefore it has a promising prospect of commercial application. The chemical structures of the compounds were confirmed by MS, IR, 1H NMR and 13C NMR.     

Effects of Exogenous Amino Acids on the Contents of Amino Acids in Tobacco Leaves

The effect of three amino acids on the growth of flue-cured tobacco was studied with water culture. The results showed that the three amino acids improved the growth of flue-cured tobacco and increased the contents of chlorophyll a,chlorophyll b and carotenoid in tobacco. At the same time, the activities of NR (nitrate reductase), INV(invertase) and root growth activity were also significantly enhanced. The exogenous glutamic, aspartate and phenylalanine all increased the amino acid contents of tobacco leaves. Of these three amino acids, glutamic had the greatest effect, the next was aspartate,and phenylalanine had the least effect. These three amino acids all had significantly increased the accumulation of amino acids in the leaves of individual plants of tobacco; and the magnitude of accumulation indicated aspartate＞glutamic＞phenylalanine.     

Amino Acids Analysis in Different Antigens and Relationship with Immunoreactivity in Cysticercus cellulosae

The six antigens of Cysticercus cellulosae: CFag, CSag, CBWag, CWag, UCWag and TSag were prepared respectively. The amino acids of the antigens were determined quantitative by automatic amino acid analyzer. The relationship of original reaction was confirmed between amino acids and antigens. The results showed that there were 17 amino acids among all of the antigens. There were no significant difference (P >0.05) of Asp, Glu, Lys, His in composition of all antigens by data analysis software SPSS. There are also no significant difference ( P ＞ 0.05) in the composition of all amino acids between CSag and CBWag. The composition of Thr, Ser, Tyr, Ved, Pro in UCWag shows significant difference (P ＜ 0.05) with other antigens.The sensitivity and peculiarity of UCWag are higher than that of the others. Pro and Glu show significant linear correspondence with sensitivity and peculiarity of antigens respectively.     

Purification of Aminopeptidase N Protein and Differences in cDNAs Encoding APN1 Between Susceptible and Resistant Helicoverpa armigera Strains to Bacillus thuringiensis Toxins

The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera were successfully separated, and most of the Aminopeptidase N (APN) activities in BBMV were preserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-l-propane-sulphonate (CHAPS) can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C (PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified using a Mono-Q column. The results of immunoblotting showed that the 120 and 170 kDa proteins in the BBMV could bind CrylAc, and 120 kDa APN was a glycosylphosphalidylinositol(GPI)-anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after being selected for more than five years in laboratory using Bt insecticides and Bt transgenic cotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1 083.3 and 48.7 times that of susceptible strain. The genes encoding APNI in midgut of susceptible and resistant H.armigera were cloned by PCR and RACE techniques. The inferred amino acid sequences of APNI possessed the common character of APN family in insects. In comparison with APNI in susceptible strain, three nucleotide mutations were observed in the APNI of Bt-M strain and resulted in two amino acid replace in the putative protein sequences, and eight nucleotide mutations were observed in Bt-P strain and resulted in five amino acid replace.     

Responses of N_2O reductase gene(nosZ)-denitrifier communities to long-term fertilization follow a depth pattern in calcareous purplish paddy soil

The effect of long-term fertilization on soil denitrifying communities was analysed by measuring the abundance and diversity of the nitrous oxide(N_2O)reductase gene,nos Z.Soil samples were collected from plots of a long-term fertilization experiment established in 1982 in Suining City,China.The fertilizer treatments were no fertilizer(CK),three chemical fertilizer(CF)treatments(N,NP,NPK),manure(M)alone,and manure with chemical fertilizers(NM,NPM,NPKM).The abundance and diversity of the denitrifying bacteria were assessed by real-time quantitative PCR,terminal restriction fragment length polymorphism(T-RFLP),and cloning and sequencing of nos Z genes.The diversity and abundance of nos Z-denitrifiers was higher in soil amended with manure and chemical fertilizers(CFM)than in soil amended with CF alone,and the highest in topsoil(0–20 cm).The nos Z-denitrifier community composition was more complex in CFM soil than in CF soil.Specific species were detected only in the CFM soil.The abundance of nos Z-denitrifier in the NPKM treatment was approximately two times higher than that in the CK,N,and NPK treatments.Most of the cloned nos Z sequences were closely related to nos Z sequences from Bradyrhizobiaceae and Rhodospirillaceae in Alphaproteobacteria.Of the measured abiotic factors,soil organic matter correlated significantly with the abundance(P0.01);available phosphorus correlated significantly with the topsoil community composition(P0.01),whereas soil organic matter correlated significantly with the subsoil(20–90 cm)community composition(P0.01).This study demonstrated that long-term CFM fertilization affected both the abundance and composition of the nos Z-denitrifier community.     

Molecular Characteristics of New Wheat Starch and Its Digestion Behaviours

In order to understand the effect of starch molecular characteristics on the gel structure, which subsequently influence the gel digestion behaviours, three wheat starches, control （conventional wheat starch）, two new wheat cultivars with different genetic backgrounds （by knocking out SBE IIb and SBE IIa, respectively） were used in this study. In comparison with control, slight differences in the morphology of the starch granules of new wheat 1 were observed, whereas the starch granules of new wheat 2 had irregular shapes both for A-type granules and B-type granules. Starch molecular weight size was determined by SE-HPLC, and the results indicate that there was a subtle increase in the amylose content in the starch of new wheat 1 compared to that of control. The starch of new wheat 2 had the highest amylose content, and the molecular weight （MW） of its amylopectin was the lowest among the three starches. Fourier transform infrared spectroscopy （FTIR） was employed to investigate starch gel structure and the results suggest that the molecules of starch gel from new wheat 2 are more likely to re-associate to form an organized conformation. The digestion behaviours of the three starch gels were measured using a mixture of pancreatin a-amylase and amyloglucosidase. The results indicated that the starch gels of control and new wheat 1 had very high digestibility of 91.7 and 91.9%, respectively, whereas the digestibility of wheat 2 starch gel was only 36.2%. In comparison with the digestion curve pattems of control and new wheat 1 starch gels, the new wheat 2 exhibited a much lower initial velocity. These results indicated that the molecules in the starch of new wheat 2 are more readily to re-associate to form an organized structure during gel formation because of its unique molecular characteristics.     

Functional diversity of soil microbial communities in response to supplementing 50% of the mineral N fertilizer with organic fertilizer in an oat field

The effects of supplementing 50% of the mineral N fertilizer with organic fertilizer on the metabolism and diversity of soil microbial communities in an oat field were investigated using Biolog-Eco plates. The experiment consisted of five treatments: no fertilizer(CK), mineral N fertilizer applied at 90 and 45 kg ha–1 N in the form of urea(U1 and U2, respectively), and U2 supplemented with organic fertilizer in the form of sheep manure at 90 and 45 kg ha–1 N(U2 OM1 and U2 OM2, respectively). Each treatment had three replications. The experiment was conducted in 2018 and 2019 in Pinglu District, Shanxi Province, China. The carbon source utilization by soil microbial communities, such as amino acids, amines, carbohydrates, carboxylic acids, and polymers, increased when 50% of the mineral N fertilizer was replaced with organic fertilizer in both years. This result was accompanied by increased richness, dominance, and evenness of the microbial communities. The utilization of amino acid, amine, and carboxylic acid carbon sources and community evenness were further improved when the organic fertilizer amount was doubled in both years. Biplot analysis indicated that amines and amino acids were the most representative of the total carbon source utilization by the soil microbial communities in both years. The highest oat yield was achieved at a total N application rate of 135 kg ha–1 in the treatment involving 45 kg ha–1 N in the form of urea and 90 kg ha–1 N in the form of sheep manure in both years. It was concluded that the application of 50% of the conventional rate of mineral N fertilizer supplemented with an appropriate rate of organic fertilizer enhanced both the functional diversity of soil microbial communities and oat yield. Amine and amino acid carbon sources may be used as a substitute for total carbon sources for assessing total carbon source utilization by soil microbial communities in oat fields in future studies.     

Effects of molasses on the fermentation characteristics of mixed silage prepared with rice straw,local vegetable by-products and alfalfa in Southeast China

This experiment was conducted to study the effect of molasses on the fermentation characteristics of mixed silage ensiled rice straw and vegetable by-products with alfalfa.Mixture(202 g kg~(–1) dry matter(DM))consisting of rice straw,broccoli residue and alfalfa at the ratio of 5:4:1 was ensiled with three experimental treatments:(1)no additives(control);(2)molasses at 2.5%(M1);(3)molasses at 5%(M2)on a fresh matter basis of mixture,respectively.All treatments were packed into laboratory-scale silos,and three silos per treatment were sampled on days 1,3,5,14 and 30.The result showed that the p H value of all mixed silages decreased gradually with the time of ensiling except for the control silage,in which a significant increase(P0.05)on day 30 occurred.The lactic acid content increased gradually with the time of ensiling and reached the highest value on day 14,and a marked decrease(P0.05)was found in the control silage on day 30.The changes of acetic acid content showed similar pattern with lactic acid content.A trace amount of propionic and butyric acid contents were found in the three mixed silages during the fermentation period.Comparing to the control,M1 and M2 treatments improved the fermentation quality of mixed silages as indicated by higher(P0.05)lactic acid contents and lower(P0.05)p H and ammonia-N contents.The Flieg points also showed that M1 and M2 silages were well preserved,whereas the control silage had a bad quality.Overall,the findings of this study suggested that adding molasses could improve fermentation quality of mixed silage,and M1 was more suitable for practical application.     

Identification of SSR Marker Linked to a Major Dwarfing Gene in Common Wheat

A segregating population with 410 F 2 individuals from the cross MERCIA(Rht-B1a) ×Dwarf 123 was made to identify a new major dwarfing gene carrying by novel wheat germplasm Dwarf 123.Combination of bulk segerant analysis method was used.A total of 145 SSR markers were tested for polymorphisms among parental lines and DNA bulks of F 2 population.Out of 145 primer pairs only three markers revealed corresponding polymorphism among parental lines and F 2 DNA bulks.The marker Barc20 was close to the dwarfing gene with a genetic distance of 1.8 cM,and markers Gwm513 and Gwm495 were linked to the gene with genetic distance of 6.7 and 13 cM,respectively.Linkage analysis mapped the dwarfing gene to the long arm of chromosome 4B with the order of Barc20-dwarfing gene-Gwm513-Gwm495.The Comparision between the new gene and the known Rht-B1 alleles showed that dwarfing gene Rht-Ai123 was different from the others.The identification of the new dwarfing gene and its linked markers will greatly facilitate its utilization in wheat high yield breeding for reducing plant height.     

Mapping quantitative trait loci associated with starch paste viscosity attributes by using double haploid populations of rice(Oryza sativa L.)

The paste viscosity attributes of starch, measured by rapid visco analyzer(RVA), are important factors for the evaluation of the cooking and eating qualities of rice in breeding programs. To determine the genetic roots of the paste viscosity attributes of rice grains, quantitative trait loci(QTLs) associated with the paste viscosity attributes were mapped, using a double haploid(DH) population derived from Zhongjiazao 17(YK17), a super rice variety, crossed with D50, a tropic japonica variety. Fifty-four QTLs, for seven parameters of the RVA profiles, were identified in three planting seasons. The 54 QTLs were located on all of the 12 chromosomes, with a single QTL explaining 5.99 to 47.11% of phenotypic variation. From the QTLs identified, four were repeatedly detected under three environmental conditions and the other four QTLs were repeated under two environments. Most of the QTLs detected for peak viscosity(PKV), trough viscosity(TV), cool paste viscosity(CPV), breakdown viscosity(BDV), setback viscosity(SBV), and peak time(PeT) were located in the interval of RM6775–RM3805 under all three environmental conditions, with the exception of pasting temperature(PaT). For digenic interactions, eight QTLs with six traits were identified for additive×environment interactions in all three planting environments.The epistatic interactions were estimated only for PKV, SBV and PaT. The present study will facilitate further understanding of the genetic architecture of eating and cooking quality(ECQ) in the rice quality improvement program.