Feeding Practices and Use of Lysine and Methionine in Pigrationing on Intensified Pig Breeding in the West Center and Hauts Bassins Regions of Burkina Faso

The aim of the study was to assess feeding practices and the use of lysine and methionine in pig rationing on intensified and semi-intensive pig breeding in the Koudougou and Bobo-Dioulasso areas. To this end, a cross-sectional survey was carried out on 87 breeding in these towns. A Discriminant Factorial Analysis (DFA) confirming a k-means classification of the data collected was used to retain 71 breeding divided into three breeding classes: Class A (32.4% of breeding), Class B (14.08%) and Class C (53.52%). The results show that the majority of pig breeders were men between the ages of 36 and 59. Average herd sizes were 35 ± 28;79 ± 42 and 89 ± 21 pigs for Classes A, B and C respectively. The main breeds of pig found on the breeding were crossbred, Large white, local, Landrace and Duroc. Class A (26.1%), B (30%) and C (15.8%) breeders were familiar with both lysine and methionine. Class A breeders distributed feed staggered (65.2%) and in rations (34.8%). Lysine (13%) and methionine (8.7%) were purchased at 5250 FCFA/kg. Those in class B distributed feed staggered (50%) and in the form of rations (50%), in which they incorporated lysine (30%) and methionine (30%) purchased at a cost of 2500 FCFA/kg and 3000 FCFA/kg respectively. Rationing and staggered feeding were practiced by 23.7% and 76.3% of Class C breeders respectively. Only lysine purchased at 3400 FCFA/kg was incorporated into rations by 10.5% of breeders. The high cost of lysine and methionine was incriminated by Class A (100%), B (33.3%) and C (50%) breeders. In conclusion, intensive pig breeding, the practice of rationing and the incorporation of the amino acids lysine and methionine are of ascending importance from classes C, A to B. The high cost of feedstuffs, particularly lysine and methionine, compromises their use in rations, which could have a negative impact on expected breeding performance. The screening and use of feeds rich in and/or enriched with these amino acids, through the development or adaptation of technologies, could improve the efficiency of rations and the productivity of intensive pig breeding in Burkina Faso.

Study on Lysine and Methionine Content Promotion of Soybean Meal by Probiotic Fermentation Process

Soybean meal （SBM） is commonly used for livestock feeds, but its application in diets for livestock is limited due to some antinutritional factors. The contents of methionine and lysine of soybean meal were promoted by Bacillus natto and Leuconostoc mesenteroides fermentation, benefial for the livestock feeds. It was crude protein （CP） 56.8%, methionine 43.56 mg · g^-1, and lysine 74.87 mg · g^-1, cows fed a diet with FSBM milk yield raised 14.2%, the change in the milk protein, the lactose and the dry matter content had also obvious increase. This convenient technique offers helpful exploration for industrialization of soybean meal fermentation.

Lysine, Methionine and Tryptophan Requirements of Beijing Ducklings of 0-2 Weeks of Age

A feed trial was conducted with a total of 1 134 Beijing ducklings to study the optimum level of dietary lysine （Lys） （0.95, 1.10, 1.25%）, methionine （Met） （0.26, 0.46, 0.66%） and tryptophan （Trp） （0.20, 0.30, 0.40%） for those ducklings during a phase of 0-2 weeks. Ducklings were randomly allotted to 27 groups according to a 3 × 3× 3 factorial arrangement and fed a basal corn-soybean-peanut meal diet containing 20.26% CP, 12.45 MJ kg^-1 ME. The results from this study indicate that Lys affected body weight （P〈0.01）, feed intake （0-14 d） （P〈0.01）, but had no effect on feed/gain （0-14 d） （P〉0.05）, uric acid concentration （P 〉 0.05）. Methionine influenced body weight （P 〈 0.01）, feed/gain （P 〈 0.05）, and feed intake （P 〈 0.01）. Tryphtophan had no effect on indices measured. The requirement of the Lys and Met for Beijing ducklings of 0-2 weeks of age were 1.10 and 0.46%. The requirement of Trp for Beijing ducklings of 0-2 weeks of age was not more than 0.20%.

An Elevated Dietary Cysteine to Methionine Ratio Does Not Impact on Dietary Methionine Efficiency and the Derived Optimal Methionine to Lysine Ratio in Diets for Meat Type Chicken

Optimal dietary methionine (Met) to lysine (Lys) ratio in presence of elevated dietary cysteine (Cys) levels was derived for meat type growing chicken. Twelve averaged weighed Ross 308 birds (each 50% of male and female per dietary treatment) were utilized in N balance trials. During starter (d10 - 20) and grower period (d25 - 35) five dietary treatments were used. Diets based on uniform mixtures of maize, wheat, soybean meal, potato protein and fish meal were supplemented with crystalline amino acids (AA). In diets 1 - 3, the dietary Cys to Met ratio was set as 85, 95 and 105 to 100, respectively. Diet 4, at a Cys to Met ratio of 105 to 100, was additionally supplemented with betaine (BET) as methyl group donor. Diets 1 - 4 were limiting in Met, diet 5 without L-Lys·HCl addition was limiting in Lys. Individual N-balance data per treatment were utilized for assessing protein quality and efficiency of dietary Met (Diets 1 - 4) or Lys (Diet 5) based on “Goettingen approach”. Elevated dietary Cys supply and supplemented BET failed to improve both dietary protein quality and Met efficiency. The established optimal Met to Lys ratio was on average 34 to 100 for growing chicken during starter and grower period, respectively.

Construction and Expression of Methionine-rich and Lysine-rich Fusion Gene in Bacillus natto

Methionine and lysine are restrictive essential amino acids of livestock, they are also the most attentive indexes in the feed production to carry out the quality control and quality evaluation. Their contents in feed directly affect livestock protein synthesis. Bacillus natto has excellent probiotic properties. In this experiment, we used the genetic engineering method, fusion PCR technique, to connect methionine-rich gene （zein） from maize endosperm protein with lysine-rich gene （Cflr） from the pepper anther, then the fusion gene was inserted into the expression vector pHT43, and the recombinant plasmid pHT43/zein-Cflr was constructed. The recombinant plasmid was transferred into Bacillus natto, and induced by IPTG for the expression of the fusion gene. We found an apparent band at 40 ku site for the recombinant strain by SDS-PAGE. The contents of methionine and lysine were individually detected with HPLC, the quantities of methionine and lysine in the recombinant strain increased by 18.37% and 24.68% than the wild one, respectively. We also verified the stability of the recombinant bacterium during passaging, and found the stability was 100%. This study provided research-basis for the application of the recombined Bacillus natto as feed additive.

Lipid metabolism and m^(6)A RNA methylation are altered in lambs supplemented rumen-protected methionine and lysine in a low-protein diet

Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rumen-protected methionine and lysine(RML)in a low-protein(LP)diet on lipid metabolism,m^(6)A RNA methylation,and fatty acid(FA)profiles in the liver and muscle of lambs were investigated.Sixty-three male lambs were divided into three treatment groups,three pens per group and seven lambs per pen.The lambs were fed a 14.5%crude protein(CP)diet(adequate protein[NP]),12.5%CP diet(LP),and a LP diet plus RML(LP+RML)for 60 d.Results:The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin(P=0.07),triglyceride(P=0.05),and non-esterified FA(P=0.08).Feeding a LP diet increased the enzyme activity or m RNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet.This effect was reversed by supplementation of RML with a LP diet.The inclusion of RML in a LP diet affected the polyunsaturated fatty acids(PUFA),n-3 PUFA,and n-6 PUFA in the liver but not in the muscle,which might be linked with altered expression of FA desaturase-1(FADS1)and acetyl-Co A carboxylase(ACC).A LP diet supplemented with RML increased(P<0.05)total m^(6)A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein(FTO)and alk B homologue 5(ALKBH5).The m RNA expressions of methyltransferase-like 3(METTL3)and methyltransferase-like 14(METTL14)in the LP+RML diet group were lower than those in the other two groups.Supplementation of RML with a LP diet affected only liver YTH domain family(YTHDF2)proteins(P<0.05)and muscle YTHDF3(P=0.09),which can be explained by limited m^(6)Abinding proteins that were mediated in m RNA fate.Conclusions:Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle.These changes in fat metabolism may be associated with the modification of m^(6)A RNA methylation.

Different dietary methionine to lysine ratios in the lactation diet:effects on the performance of sows and their offspring and methionine metabolism in lactating sows

Background:Over the last decade,the nutritional requirements of lactating modern genotype sows have increased.The current nutritional recommendations might be unable to meet the needs of increased litter size and milk production,and thus the nutritional requirements need to be re-evaluated.The current study was conducted to investigate the effects of dietary methionine to lysine(Met:Lys)ratios on the performance of and methionine metabolism in lactating sows.Results:During the 1st week of lactation,piglets reared on sows in the 0.37 to 0.57 Met:Lys ratio groups grew faster than those reared on sows in the control group(0.27)(P<0.01).The 0.37-ratio group showed increased levels of GSHPx in plasma during lactation(P<0.01)and decreased concentrations of urea nitrogen in the plasma of sows(P<0.05).Compared with the 0.27-ratio group,the levels of T-AOC and GSH-Px in the plasma and homocysteine in the milk of lactating sows were significantly increased in sows in the 0.47-ratio group(P<0.01).In sows fed a 0.57-ratio diet,the levels of glutathione and taurine in the plasma and milk were improved significantly during lactation.However,the content of TBARS in the blood(P<0.05 at day 7 and P=0.06 at weaning day)was increased(P<0.01).Moreover,there were linear increases in the levels of homocysteine in the blood and milk of sows during the lactation period(P<0.01)with increased dietary Met:Lys ratios in the lactation diet.Conclusions:The current study indicated that increasing the dietary Met:Lys ratio(0.37~0.57)in the lactation diet had no significant effect on the overall performance of sows or the colostrum and milk composition,but it increased piglet mean BW and piglet ADG during the first week of lactation.Increasing dietary methionine levels had no significant effect on antioxidant function in lactation sows,even though it increased levels of GSH and GSH-Px in the plasma of sows during lactation.However,the content of homocysteine in the plasma and milk increased during lactation due to a high level of dietary methionine.

Identification of the lysine and histidine transporter family in Camellia sinensis and the characterizations in nitrogen utilization

In plants,the lysine and histidine transporter(LHT)family represent a class of proteins that mediate the uptake,translocation,and utilization of amino acids.The tea plant(Camellia sinensis)is a perennial evergreen with a relatively high level of amino acids.However,systematic identification and molecular characterization of the LHT gene family has rarely been reported in tea plants.In this study,22 CsLHTs were identified from the‘Shuchazao’genome and classified into two groups.The modeled three-dimensional structure and the conserved domains presented a high similarity among the LHTs proteins.Moreover,it was predicted that a few genes were conserved through the analysis of the physiochemical characters,structures and cis-elements in promoters.The expression patterns in tea plants revealed that CsLHT7 was mainly expressed in the roots,and CsLHT4 and CsLHT11 exhibited relatively high expression in both the roots and leaves.Moreover,the expression of all three genes could be induced by organic nitrogen.Additionally,heterogeneous expression of CsLHT4,CsLHT7 and CsLHT11 in Arabidopsis thaliana decreased the aerial parts biomass compared with that in WT plants while significantly increased the rosette biomass only for CsLHT11transgenic plants versus WT plants.Overall,our results provide fundamental information about CsLHTs and potential genes in N utilization for further analysis in tea plants.

Bacillus subtilis Co-transfected with a Lysine-rich and a Methionine-rich Protein Gene and Its Effect on Cow Milk Production

The probiotic Bacillus subtilis （B. subtilis） was widely applied in animal production as feed additive. Lysine （Lys） and methionine （Met） were the two most important limiting amino acids in livestock animal feed. Raising Lys and Met contents in B. subtilis would provide better effects for animal production and save Lys and Met supplements. We still didn＇t know whether Lys- rich and Met-rich protein genes from plants could be transfected into B. subtilis and expressed at a high level so as to improve animal production, such as milk production as an additional diet. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were cloned from pepper anther and maize endosperm, respectively. Then they were constructed into plasmids individually and successfully cotransfected into B. subtilis. Upon IPTG induction, mRNAs and protein expressions could be observed. Lys and Met contents in the fermentation broth were raised by 65.92% and 46.39%, respectively. After feeding 200 g and 400 g· cow^-1· d^-1, transgenic B. subtilis fermentation broth, the milk yield, milk protein and milk fat contents all significantly increased. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were successfully transfected into B. subtilis. Contents of Lys and Met in the transgenic B. subalis obviously raised and the fermentation broth of the transgenic bacteria could effectively improve milk yield and quality.

Effects of methionine supplementation in a reduced protein diet on growth performance, oxidative status, intestinal health, oocyst shedding, and methionine and folate metabolism in broilers under Eimeria challenge

Background This study investigated effects of different methionine(Met)supplementation levels in a reduced protein diet on growth performance,intestinal health,and different physiological parameters in broilers under Eimeria challenge.A total of 600 fourteen-day-old Cobb500 male broilers were challenged with E.maxima,E.tenella,and E.acervulina,and randomly allocated in a 2×5 factorial arrangement.Birds received normal protein diets(20%crude protein,NCP)or reduced protein diets(17%crude protein,LCP),containing 2.8,4.4,6.0,7.6,and 9.2 g/kg of Met.Results On 6 and 9 days post inoculation(DPI),increasing Met level linearly improved the growth performance(P<0.05).Total oocyst shedding linearly increased as Met level increased(P<0.05).Duodenal villus height(VH):crypt depth(CD)in the LCP groups were higher on 6 DPI(P<0.01)while lower on 9 DPI(P<0.05)compared to the NCP groups.Jejunal CD and duodenal VH:CD changed quadratically as Met level increased(P<0.05).On 6 DPI,liver glutathione(GSH)and glutathione disulfide(GSSG)linearly increased as Met level increased(P<0.05).On 9 DPI,GSSG quadratically increased,whereas GSH:GSSG quadratically decreased as Met levels increased(P<0.05).The expression of amino acid transporters linearly decreased as Met level increased(P<0.05).The expression of zonula occludens 2 and claudin-1 linearly increased on 6 DPI whereas decreased on 9 DPI as Met level increased(P<0.05).The expressions of cytokines were lower in the LCP groups than the NCP groups(P<0.05).Interaction effects were found for the expression of IL-10 and TNFαon 6 DPI(P<0.05),where it only changed quadratically in the NCP group as Met level increased.The expression of Met and folate metabolism genes were lower in the LCP groups than the NCP groups on 9 DPI(P<0.05).The expression of these genes linearly or quadratically decreased as Met level increased(P<0.05).Conclusion These results revealed the regulatory roles of Met in different physiological parameters including oxidative status,intestinal health,and nutrient metabolism in birds fed reduced protein diet and challenged with Eimeria.

Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine

The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.

Wetting alternating with partial drying during grain filling increases lysine biosynthesis in inferior rice grain

Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.

Improvement of glucose metabolism in middle-aged mice on a high-fat diet by whole-grain highland barley is related to low methionine levels

Methionine restriction(MR)is an effective dietary strategy to regulate energy metabolism and alleviate oxidative stress and inflammation in the body,especially in the middle-aged and elderly population.However,the high methionine content of meat products makes this dietary strategy impossible to combine with protein supplementation and MR.Highland barley(HB),a low-methionine cereal,not only provides the body with protein but also has improved glucose metabolism and antioxidant and anti-inflammatory properties.Therefore,this study evaluated the feasibility of HB as a source of methionine-restricted dietary protein and the potential mechanisms.Middle-aged C57BL/6J mice were fed a control diet(CON),a high-fat diet(HFD),a whole-grain HB high-fat diet(HBHF),or a HBHF+methionine diet(HBHFmet)for 25 weeks.The results showed that the HBHF could keep the body weight,fasting glucose,insulin,homeostasis model assessment of insulin resistance(HOMA-IR),blood lipids,inflammation,and oxidative stress of HFD mice at normal levels.Compared with the HFD groups,HBHF inhibited pancreatic cell apoptosis and improved insulin secretion while improving hepatic and skeletal muscle glucose metabolism.However,these efficacies were attenuated in HBHFmet group mice.These findings suggest that HBHF has an MR strategy.

Effect of exogenous free N^(ε)-(carboxymethyl)lysine on diabetes-associated cognitive dysfunction:neuroinflammation,and metabolic disorders

Diabetes-associated cognitive dysfunction has already been attracted considerable attention.Advanced glycation end products(AGEs)from daily diets are thought to be a vital contributor to the development of this diseases.However,the effect of one of the best-characterized exogenous AGEs N^(ε)-(carboxymethyl)lysine(CML)on cognitive function is not fully reported.In the present study,diabetical Goto-Kakizaki(GK)rats were treated with free CML for 8-weeks.It was found that oral consumption of exogenous CML significantly aggravated diabetes-associated cognitive dysfunction in behavioral test.In details,exogenous CML increased levels of oxidative stress,promoted the activation of glial cells in the brain,up-regulated the release of inflammatory cytokines interleukin-6,inhibited the protein expression of the brain-derived neurotrophic factor and thus led to neuroinflammation.Furthermore,exogenous CML promoted the amyloidogenesis in the brain of GK rats,and inhibited the expression of GLUT4.Additionally,several tricarboxylic acid cycle and glutamate-glutamine/γ-aminobutyric acid cycle intermediates including pyruvate,succinic acid,glutamine,glutamate were significantly changed in brain of GK rats treated with exogenous free CML.In conclusion,exogenous free CML is a potentially noxious compounds led to aggravated diabetes-associated cognitive dysfunction which could be possibly explained by its effects on neuroinflammation,energy and neurotransmitter amino acid homeostasis.

Effects of Supplemental Glutamine and Lysine on Growth Performance of Broiler Chickens

The optimum levels of Lysine and Glutamine needed for growth performance and maintenance of the chicken broilers were evaluated in a randomized 3 × 4 factorial arrangement of dietary treatments. The battery cages measured 99 × 66 × 25 cm that can be sufficient for 5 birds. Day old Chicken broilers totaling 180 were assigned to dietary treatments comprising of 3 concentrations of Lysine (0.85, 1.14, and 1.42) each in combination with 4 concentrations of Glutamine (0, 1, 2, and 3). Each dietary treatment was replicated 3 times and each replication had 5 birds. The birds were given feed and water ad libitum with a 23-hour light regimen for a period of 4 weeks. Then, the experimental birds were evaluated for body weight gain, feed consumption, and feed conversion in order to determine their optimum requirement for dietary Lysine and Glutamine. Based on the findings of this study, the highest performance was observed in birds fed the diet supplemented with 1.42 lysine and 1% glutamine, but the highest improvement in feed conversion was observed in diet contain 1.14 and 1.42 with 1% and 3% glutamine, respectively. Birds fed 1.42 lysine and 1% glutamine had the highest total body weight gain and feed consumption. The lysine requirements in the diet for Chicken are between 1.14 and 1.42 with glutamine level of 1%.

Transfer of Lysine-rich Protein Gene into Rice and Production of Fertile Transgenic Plants

Lysine-rich protein gene (lys) was cloned from Psophocarpus tetragonolobus (L.) DC. A plant expression plasmid was constructed and lys gene was under the control of maize ubiquitin promoter which is the highest efficient monocotyledon promoter. The plasmid was introduced into rice embryogenic calli by microprojectile bombardment. The regenerated fertile plants were obtained by effective selection for hygromycin B resistance. Genomic PCR and Southern blotting analyses showed that the lys gene has been integrated into rice genome. Simultaneously, the results of GUS histochemical assay demonstrated that gus report gene is also expressed in leaves, stems and roots of the transgenic rice plants. Data analysis showed that lysine content in most of the 11 transgenic plants is differently improved, and in one of them increased by 16.04%.

Effect of Low Temperature Stress on Sweet Potato S-Adenosyl Methionine Synthetase Gene Expression

[Objective] The mRNA expression level changes of S-adenosylmethionine synthetase （SAMS） under low temperature stress was studied. [Method] Total RNA were extracted from leaves, stem and earthnut of sweet potato 0,12,24,48 and 72 h after low temperature treatement, mRNA expression level was analyzed by reverse expression and Real-time PCR technique. [Result] The expression quality of the gene extracted from leaves, stem and earthnut increased and the expression quality reached the peak point 24,72 and 72 h after low temperature treatment respectively. The expression change of earthnut was the biggest. [Conclusion] Low temperature was good for increasing mRNA expression of relevart genes.

SELECTION OF METHIONINE-RESISTANT VARIANT OF MEDICAGO SATIVA

A variant cell line of Medicago saliva L. resistant to methionine (100 mmol/L) was selected .from calli treated with 1.5 mmol/L sodium azide. Plants were regenerated from this selected cell line. After growing for 6 months on the medium devoid of selection pressure, the variant cell line still showed high level of resistance, which was 7.2-fold higher than that of the wild type. This indicated the stability of the resistance expression. The variant cell line also expressed a 3.3-fold higher cross-resistance to ethionine, than that of the wild type. The contents of methionine, lysine, threonine and isoleucine in the variant calli were respectively 2.0, 1.43, 1.71 and 1.57 times higher than those in the wild type. However, in the variant regenerated plantlets they respectively were 2.0, 1.33, 1.22 and 1.22 times higher than those in the wild type regenerants. Four new protein bands, viz. 65 kD, 23 kD, 20 kD and 18 kD, appeared in the SDS-PAGE pattern of soluble proteins in the variant calli. In the peroxidase isoenzyme electrophoresis pattern, two new bands were also observed in the variant calli.

Poly-L-Lysine玻片在寡核苷酸芯片制备中的改进

目的为了制得适合固定未修饰寡核苷酸的芯片,提高检测灵敏性,对Patrick Brown 实验室的多聚左旋赖氨酸包被玻片的方法进行改进。方法玻片经清洗后用缩水甘油-丙氧基三甲氧基硅烷进行硅烷化,然后应用Poly-L-Lysine在玻片表面形成聚合物涂层,经次亚苯基二异硫氰酸盐表面活化后可使寡核苷酸共价连接在芯片表面。设计了各种实验考察方法改进前后芯片表面的性能,并将改进后的玻片初步应用于SARS冠状病毒寡核苷酸芯片检测中。结果方法改进后芯片表面性能优良:固定效率高、点的同一性好、杂交效率和热稳定性好、寡核苷酸结合牢固、芯片可以重复利用。结论利用共价连接,方法改进后的芯片表面适合固定未修饰的寡核苷酸,解决了寡核苷酸与玻片之间物理结合不稳定、易剥离的缺陷,提高了芯片检测的灵敏性。

Rapid Determination of Lysine Content in Maize Kernel by Amino-acid Analyzer

In this study, nine high-lysine maize kernels and two kernels of common maize hybrid were used as experiment materials, and quantitative determination of lysine contents in high-lysine maize kernels and common maize kernels was carried out using Hitachi L-8900 Automatic Amino-acid Analyzer, to know the effect of the Analyzer in distinguishing the lysine contents between common maize kernels and high-lysine maize kernels. The results showed that the lysine contents of high-lysine maize kernels were among 0.34%-0.42%, while of common maize kernels were a- mong 0.24%-0.25%, and the difference was significant. Compared with other tradi- tional methods, this method is rapid, simple, sensitive, highly reproductive and needs fewer maize kernels, thus it is applicable in maize breeding.