The freezing characteristics of cauliflower curd

Cultivar differences in frost resistance and the heritable nature of resistance were demonstrated using seedling cauliflower plants. Such cultivar differences were not however expressed in the curd. Selection for frost resistance in cauliflower should therefore use whole plant screening techniques. Curd material when frozen as isolated florets, supercooled over the range – 1°C to – 12°C and the mean freezing point of all curds tested was -6°C to -7.25°C (overall mean -6.44°C). Curd florets which supercooled but did not freeze were completely undamaged, whereas freezing always led to cell damage and death observed as water-soaking of the floret surface and measured using an electrical conductivity method. The large range of freezing points measured suggests a range of active ice nucleators either on or within the florets. When curds were frozen intact the ability of florets to supercool was severely restricted which was attributed to the seeding of freezing by the internal growth of ice crystals. A crop protection strategy needs to identify and control or modify warm temperature nucleators in cauliflower curd.     

Optimization of whole cell-catalyzed methanolysis of soybean oil for biodiesel production using response surface methodology

Utilizing whole cell biocatalyst instead of free or immobilized enzyme is a potential way to reduce the cost of catalyst in lipase-catalyzed biodiesel production. Rhizopus oryzae (R. oryzae) IFO4697 whole cell immobilized within biomass support particles (BSPs) was used for the methanolysis of soybean oil for biodiesel production in this paper. tert-Butanol was demonstrated to be an ideal reaction medium, in which the negative effects caused by substrate methanol could be eliminated effectively. A central composite design was adopted to study the effect of tert-butanol quantity, methanol quantity, water content and dry biomass of the immobilized cell on biodiesel (methyl ester) yield. Each factor was studied in five levels. Using response surface methodology, a quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis. Biodiesel yield of 72% could be obtained under the optimal conditions and further verification experiments confirmed the validity of the predicted model.     

Purification and characterization of two tyrosyl-tRNA synthetase activities from soybean cotyledons

The tyrosyl-tRNA synthetases located in cytoplasm and chloroplasts of soybean cotyledons were purified to near homogeneity by ammonium sulfate precipitation, DEAE-cellulose chromatography, hydroxylapatite chromatography, and DEAE-Sephadex A-25 chromatography. Purified cytoplasmic tyrosyl-tRNA synthetase shows only a single band in acrylamide gel electrophoresis which corresponds to a MW of 126000. In SDS-acrylamide gel electrophoresis the enzyme again shows only a single band which corresponds to a MW of 61 000. Chloroplast tyrosyl-tRNA synthetase shows only one band in both acrylamide and SDS-acrylamide gel electrophoresis with MWs being 98 000 and 43 000, respectively. For cytoplasmic tyrosyl-tRNA synthetase the apparent K_ms determined are 6.8 μM L-tyrosine, 49 μM ATP, and 8.9 × 10^?8 M tRNA (as total tRNA). Apparent K_ms for chloroplast tyrosyl-tRNA synthetase are 4.9 μM L-tyrosine, 214 μM ATP and 2.2 × 10^?8 M tRNA (as BDC-ethanol fraction tRNA). Fractionation of soybean cotyledon-tRNA on RPC-5 columns gives 4 tyrosyl-tRNA species, the first two species (tRNA_{1 and 2}^Tyr) are acylated only by cytoplasmic tyrosyl-tRNA synthetase while the last two species (tRNA_{3 and 4}^Tyr) are acylated only by chloroplast tyrosyl-tRNA synthetase.     

臭氧胁迫下硅对大豆抗氧化系统、生物量及产量的影响

在全球变化情景下,臭氧污染对作物产量将造成严重影响,臭氧将成为未来农业重要胁迫因素。研究缓解臭氧胁迫技术措施有利于保障粮食安全,其中硅元素添加可能是有效途径之一。利用开顶式同化箱(open top chambers,OTCs)装置,设置两个O3浓度(大气O3浓度<40μg/kg和高O3浓度约为80μg/kg)、两个硅浓度(0和100μg/g),研究不同O3浓度下硅对开花后大豆(Glycine max)株高、叶面积、叶绿素含量、抗氧化系统及产量的影响。结果表明:在无臭氧胁迫下,施硅可显著提高大豆根生物量、总生物量和单株籽粒重(14%、5%和20%)(P<0.05)。在O3胁迫下,施硅能使大豆维持较高的叶面积,显著提高大豆叶片叶绿素含量及SOD、POD、CAT活性,显著降低MDA含量,提高大豆根生物量、地上部生物量、总生物量、根冠比和单株籽粒重(29%,18%,19%,9%和17%)(P<0.05)。研究可为缓解O3对大豆危害提供合理可行的栽培管理措施与理论依据。     

大豆糯米复合甜酒酿的制备及发酵过程中的生物学特性

以糯米为主要原料,以定量的大豆作为辅助原料配制复合甜酒酿。通过四因素三水平正交实验确定了大豆的添加量、发酵温度、发酵时间及接种量,并对发酵过程酵母数量、糖化酶活力、还原糖变化规律进行了系统研究。结果表明:加入8%(质量分数,下同)的大豆,拌进0.5%(体积分数,下同)酒曲药,在32℃下恒温发酵42 h,甜酒酿酒香协调且有特殊香味,滋味协调绵甜,达到最优品质。发酵过程中,酵母的数量在22~34 h内急剧增加,34~56 h后进入稳定期,菌数基本保持不变;糖化酶活力在发酵22~37 h内迅速增大,37 h以后糖化酶的活力逐渐下降;22~36 h内还原糖的含量快速增加,36 h以后还原糖的含量增加缓慢,64 h达到高峰。     

Isolation and characterization of a root nodule-specific cysteine proteinase cDNA from soybean

We have determined that a nodule-specific cDNA clone (GmCysP1), obtained from a soybean root nodule-specific EST pool, encodes cysteine proteinase. Its amino acid sequence homology, as well as the conservation of typical motifs and amino acid residues involved in active site formation, shows that GmCysP1 can be classified as a legumain (C13) family cysteine proteinase, belonging to clan CD. Moreover, based on its expression patterns,GmCysP1 is a nodule-specific cysteine proteinase gene that is possibly associated with nodule development or senescence. Our genomic Southern analysis also suggests thatGmCysP1 is a member of a multigene family. Therefore, we propose that GmCysP1 is the first to be identified as a nodule-specific and senescence-related cysteine proteinase that belongs to the legumain family from soybean.     

内蒙古地区传统制作奶豆腐和乌日莫中乳酸菌多样性及分布特征

【背景】传统制作奶豆腐和酸性奶油(乌日莫)是内蒙古农牧地区最喜爱的食品,蕴含着十分丰富的乳酸菌资源,亟待开发利用。【目的】通过解析内蒙古农牧地区传统自制奶豆腐和乌日莫样品中乳酸菌多样性及分布特征,为优良菌株选育与利用提供资源和理论基础。【方法】采用稀释涂布法分离纯化乳酸菌,测定菌株16S rRNA基因序列鉴定种属关系,阐明乳酸菌系统发育、遗传分化及菌群结构。【结果】传统自制样品中共分离得到乳酸菌81株,主要归属于乳酸片球菌(Pediococcus acidilactici)、戊糖片球菌(Pediococcus pentosaceus)、短乳杆菌(Lactobacillus brevis)、瑞士乳杆菌(Lactobacillus helveticus)、副干酪乳杆菌(Lactobacillus paracasei)、食二酸乳杆菌(Lactobacillus diolivorans)、奥塔基乳杆菌(Lactobacillus otakiensis)、植物乳杆菌(Lactobacillus plantarum)、开菲尔乳杆菌(Lactobacillus kefir)、乳酸乳球菌(Lactoc...     

高效液相色谱法测定大豆乳清提取物中大豆异黄酮的含量

建立了大豆乳清提取物中大豆异黄酮含量的高效液相色谱测定方法。采用Nova-Pak C₁₈（3.9×150 mm,4 μm）色谱柱;以甲醇：0.4%磷酸=30：70（v/v）为流动相分析染料木苷和黄豆苷;流速为0.7 mL·min^-1;柱温为30℃;检测波长为260 nm。试验结果表明,大豆乳清提取物中的大豆异黄酮含量为72.5%,其组成以染料木苷和黄豆苷为主,二者比例接近1∶1,苷元型大豆异黄酮未检出。染料木苷和黄豆苷的平均回收率分别为98.1%和98.4%,相对标准偏差（RSD）分别为0.7%（n=5）和0.8%(n=5)。该方法快速、准确、重复性好。     

Evaluation of powdered pine bark for control ofMeloidogyne arenaria andHeterodera glycines on soybean

Commercially avaiable pine bark nuggets (composted) and fresh pine bark were ground into powders and added at rates of 0 to 50 g kg^–1 to field soil infested withMeloidogyne arenaria andHeterodera glycines. The treated soil was maintained moist in the greenhouse for 2 weeks, sampled, and planted with Davis soybean (Glycine max.). Eight weeks after planting, numbers ofM. arenaria andH. glycines in soil decreased with increasing amounts of composted or fresh pine bark. No juveniles were present in soil treated with 5% pine bark. The number of galls and cysts g^–1 root decreased in proportion to the amount of pine bark added to soil. Gall and cyst formation was completely eliminated at the 5% rate. Numbers of saprophagous nematodes were highest in soil with 4–5% pine bark. The activity of several soil enzymes was correlated with the addition of both composted and fresh pine bark. Fresh pine bark powder caused an increase in soil enzyme activity compared to composted pine bark, but did not provide consistent control of gall and cyst formation.Journal Series No. 18-933579 Alabama Agricultural Experiment Station     

The effects of dopamine on antioxidant enzymes activities and reactive oxygen species levels in soybean roots

In the current work, we investigated the effects of dopamine, an neurotransmitter found in several plant species on antioxidant enzyme activities and ROS in soybean (Glycine max L. Merrill) roots. The effects of dopamine on SOD, CAT and POD activities, as well as H₂O₂, O₂^•−, melanin contents and lipid peroxidation were evaluated. Three-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0), without or with 0.1 to 1.0 mM dopamine, in a growth chamber (25°C, 12 h photoperiod, irradiance of 280 μmol m⁻² s⁻¹) for 24 h. Significant increases in melanin content were observed. The levels of ROS and lipid peroxidation decreased at all concentrations of dopamine tested. The SOD activity increased significantly under the action of dopamine, while CT activity was inhibited and POD activity was unaffected. The results suggest a close relationship between a possible antioxidant activity of dopamine and melanin and activation of SOD, reducing the levels of ROS and damage on membranes of soybean roots.     

外源α-萘乙酸对花期长期干旱大豆叶片抗氧化系统的影响

以不同耐旱型品种‘南农99-6’和‘科丰1号’大豆为材料,2012年在南京农业大学牌楼试验站进行为期110 d的盆栽试验,研究大豆花期叶面喷施α-萘乙酸(NAA)对长期干旱条件下大豆植株抗氧化系统的影响.结果表明: 干旱胁迫显著降低了大豆地上部干物质量,叶片中丙二醛(MDA)含量及活性氧(ROS)水平显著升高,同时,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶（MDHAR）、谷胱甘肽还原酶(GR)和谷胱甘肽过氧化物酶(GPX)活性,还原型抗坏血酸(AsA)、还原型谷胱甘肽(GSH)含量及AsA/DHA(双脱氢抗坏血酸)和GSH/GSSG(氧化型谷胱甘肽)比值显著升高,其中‘科丰1号’大豆的抗氧化能力更高,从而维持较低的ROS水平和MDA含量.NAA可显著提高叶片中的APX、POD、CAT、MDHAR活性及AsA/DHA、GSH/GSSG比值,其中‘科丰1号’大豆叶片的脱氢抗坏血栓还原酶（DHAR）活性和AsA含量极显著增加.     

Molecular characterization of cDNAs encoding low-molecular-weight heat shock proteins of soybean

Three cDNA clones (GmHSP23.9, GmHSP22.3, and GmHSP22.5) representing three different members of the low-molecular-weight (LMW) heat shock protein (HSP) gene superfamily were isolated and characterized. A fourth cDNA clone, pFS2033, was partially characterized previously as a full-length genomic clone GmHSP22.0. The deduced amino acid sequences of all four cDNA clones have the conserved carboxyl-terminal LMW HSP domain. Sequence and hydropathy analyses of GmHSP22, GmHSP22.3, and GmHSP22.5, representing HSPs in the 20 to 24 kDa range, indicate they contain amino-terminal signal peptides. The mRNAs from GmHSP22, GmHSP22.3, and GmHSP22.5 were preferentially associated in vivo with endoplasmic reticulum (ER)-bound polysomes. GmHSP22 and GmHSP22.5 encode strikingly similar proteins; they are 78% identical and 90% conserved at the amino acid sequence level, and both possess the C-terminal tetrapeptide KQEL which is similar to the consensus ER retention motif KDEL; the encoded polypeptides can be clearly resolved from each other by two-dimensional gel analysis of their hybrid-arrest translation products. GmHSP22.3 is less closely related to GmHSP22 (48% identical and 70% conserved) and GmHSP22.5 (47% identical and 65% conserved). The fourth cDNA clone, GmHSP23.9, encodes a HSP of ca. 24kDa with an amino terminus that has characteristics of some mitochondrial transit sequences, and in contrast to GmHSP22, GmHSP22.3, and GmHSP22.5, the corresponding mRNA is preferentially associated in vivo with free polysomes. It is proposed that the LMW HSP gene superfamily be expanded to at least six classes to include a mitochondrial class and an additional endomembrane class of LMW HSPs.     

Molecular characterization of Rhizoctonia solani isolates the incitant of soybean root rot

Rhizoctonia solani isolates used in this investigation were identified as anastomosis-4 (AG-40), collected from different localities from Assiut governorate in Egypt. Pathogenicity test of seven isolates of R. solani was evaluated on soybean Giza 111 cultivar under greenhouse conditions. All tested isolates were able to infect soybean plants causing root rot with different degrees of severities, isolate No. 1, 2 and 3 showed significantly highest root rot severity, while isolate No. 5 gave the lowest percentage of root rot rating. The sodium dodecyl sulphate polyacrylamide gel electrophoresis patterns were used to compare three isolates of R. solani. There are no variations among R. solani isolates except a few exceptions according to their protein patterns. DNA markers obtained from all isolates showed genetic similarity among different isolates obtained from different geographical regions barring few exceptions. Correlation between DNA patterns of R. solani isolates and their virulence was detected, but no correlation with anastomosis groups (AG).     

大豆醛脱氢酶基因GmALDH3-1的克隆及在生殖器官中的表达

通过基因芯片技术,从大豆中鉴定了一个花优势表达基因,其在大豆花中的表达量为叶片中的85倍。通过生物信息学方法,拼接了该基因的全长序列,并通过RT-PCR克隆了该基因。BLAST检索分析表明该基因编码醛脱氢酶,命名为GmALDH3-1。GmALDH3-1包含一个1485 bp的开放阅读框,编码494个氨基酸残基。GmADLH3-1与白杨的醛脱氢酶PtALDH3相似性最高（氨基酸相似率83%,一致率为68%）,而与来自于人的ALDH3B的氨基酸一致率和相似率分别为39%和59%。系统发生分析表明GmALDH3-1与其它植物ALDH3亚家族成员位于一个分支,且与白杨PtALDH3和拟南芥AtALDH3F1亲缘关系最近。采用实时定量RT-PCR检测了GmALDH3-1基因在大豆叶、根和花中的表达,结果表明GmALDH3-1基因在花中高丰度表达,在根和叶中未检测到表达。运用基因芯片信息分析了GmALDH3-1在种子发育过程中的表达情况,结果表明GmALDH3-1在种子发育过程中的外表皮、内表皮、外胚珠和种脐中表达量较高。文章讨论了GmALDH3-1基因在大豆生殖器官发育中可能发挥的作用。     

超结瘤大豆和东引3号大豆形态特征及蛋白质电泳比较

本文比较超结瘤大豆和东引3号大豆生育期、形态特征及蛋白质电泳的差异.结果表明,两个品种在生长发育期、形态特征以及蛋白质电泳图谱上都存在较大差异.     

Preparation of high activity whole cell biocatalyst by permeabilization of recombinant flocculent yeast with alcohol

Flocculent yeast Saccharomyces cerevisiae YF234 (MATa ura3–52 trp1Δ2 his ade 2–1 can1–100 sta1 FLO8) cells overexpressing glyoxalase I and having strong flocculation ability were permeabilized with isopropyl alcohol and ethanol under various conditions. The treatment with 40% isopropyl alcohol significantly improves the initial reaction rates of recombinant flocculent yeast cells. Moreover, the reactivity of permeabilized flocculent yeast cells was similar to that of dispersed cells with EDTA. On the other hand, the flocculation ability of yeast cells was not affected by the treatment with alcohol solutions of various concentrations and treatment time length. Therefore, the recombinant flocculent yeast cells permeabilized with alcohol are very effective whole cell biocatalysts.     

Isolation and characterization of a soybean cDNA clone encoding the plastid form of aspartate aminotransferase

Five aspartate aminotransferase (EC 2.6.1.1; AAT) isozymes were identified in soybean seedling extracts and designated AAT1 to AAT5 based on their rate of migration on non-denaturing electrophoretic gels. AAT1 was detected only in extracts of cotyledons from dark-grown seedlings. AAT3 and AAT4 were detected in crude extracts of leaves and in cotyledons of seedlings grown in the light. AAT2 and AAT5 were detected in all tissues examined. A soybean leaf cDNA clone, pSAT17, was identified by hybridization to a carrot AAT cDNA clone at low stringency. pSAT17 had an open reading frame which could encode a 50 581 Da protein. Alignment of the deduced amino acid sequence from the pSAT17 open reading frame with mature AAT protein sequences from rat disclosed a 60 amino acid N-terminal extension in the pSAT17 protein. This extension had characteristics of a plastid transit peptide.A plasmid, pEXAT17, was constructed which encoded the mature protein lacking the putative chloroplast transit polypeptide. Transformed Escherichia coli expressed a functional soybean AAT isozyme, which comigrated with the soybean AAT5 isozyme during agarose gel electrophoresis. Differential sucrose gradient sedimentation of soybean extracts indicated that AAT5 specifically cofractionated with chloroplasts. Antibodies raised against the pEXAT17-encoded AAT protein specifically reacted with the AAT5 isozyme of soybean and not with any of the other isozymes, indicating that the soybean cDNA clone, pSAT17, encodes the chloroplast isozyme, AAT5.