响应面法优化蛹虫草深层培养产菌丝及虫草素的发酵工艺

通过单因素试验和响应面设计对蛹虫草液体深层发酵工艺进行优化.结果显示,最适的碳氮源是葡萄糖和蛋白胨;培养的适宜条件:装液量100 mL,初始pH值5.0,发酵周期为8d;对于虫草素产量影响最显著的无机盐是FeSO4.Plackett-Burman设计从8个因子中筛选出4个显著因子,经最陡爬坡和响应面设计,结果表明,葡萄糖31.58 g/L,蛋白胨34.48 g/L,腺嘌呤0.88 g/L,甘氨酸15.48 g/L为发酵培养基的最佳组合;优化条件下,虫草素的产量为917.53 mg/L,生物量为30.06 g/L,较优化前分别提高了108.30％和29.06％.     

响应面法优化蛹虫草深层培养产菌丝及虫草素的发酵工艺

通过单因素试验和响应面设计对蛹虫草液体深层发酵工艺进行优化。结果显示,最适的碳氮源是葡萄糖和蛋白胨;培养的适宜条件:装液量100 mL,初始pH值5.0,发酵周期为8 d;对于虫草素产量影响最显著的无机盐是FeSO_4。Plackett-Burman设计从8个因子中筛选出4个显著因子,经最陡爬坡和响应面设计,结果表明,葡萄糖31.58 g/L,蛋白胨34.48 g/L,腺嘌呤0.88 g/L,甘氨酸15.48 g/L为发酵培养基的最佳组合;优化条件下,虫草素的产量为917.53 mg/L,生物量为30.06 g/L,较优化前分别提高了108.30%和29.06%。     

响应面分析结冷胶发酵培养基优化研究

结冷胶是由假单胞菌发酵产生的多糖,可广泛用于食品、药品辅料中,起到凝胶、增稠等作用。通过单因素试验和响应面优化试验得到发酵培养基的最佳成分。首先,通过对结冷胶培养基中碳源、氮源和无机盐进行单因素优化,最终确定最佳碳源为葡萄糖、氮源为蛋白胨、无机盐为硫酸镁和磷酸氢二钾。采用响应面Box-Behnken Design中心组合设计优化试验,确定了葡萄糖添加量3.2%,蛋白胨添加量0.52%,硫酸镁添加量0.064%和磷酸二氢钾添加量0.15%的最优培养基成分,并建立了结冷胶发酵培养基模型。最后,对模型进行了验证,获得产胶率为1.74%。     

乳杆菌产L-乳酸发酵条件的研究

通过单因子试验确定了乳杆菌L-110产L-乳酸的碳源、氮源和最适pH值,运用正交试验对摇瓶发酵条件做了初步的研究,确定了发酵培养基中影响产酸率的主要因子的配比,优化发酵培养基为(g/L):葡萄糖100,豆粉40,磷酸氢二钾2,吐温801,硫酸镁0.1,硫酸锰0.05;培养条件为:一次性添加碳酸钙50g/L,装液量为250mL瓶装50mL培养基,静置培养,温度为37℃。其摇瓶发酵L—乳酸产量可达80g/L。     

醋糟厌氧发酵制氢的影响因素研究

以预处理后的牛粪为接种物,以醋糟为发酵底物进行厌氧发酵产氢试验,研究了底物预处理方法、发酵温度、底物浓度、初始pH值、微量金属元素添加量对产氢量的影响。结果表明,用体积分数0.7%的HCl静置处理24h为最佳预处理方法,且在最佳发酵条件(发酵温度35℃,底物浓度175g/L,初始pH值6.0)下,微量金属元素营养液添加量为2%时,产氢效果最好,累积产氢量为46.91mL/gTS。     

无载体固定化米根霉发酵生产L-乳酸工艺的优化

通过单因素试验和正交试验,优化无载体固定化米根霉发酵葡萄糖清液生产L-乳酸的工艺。试验结果表明,首批次发酵工艺主要参数为:葡萄糖120g/L,NHNO33g/L,HPO0.214g/L,ZnSO4·7HO0.22g/L,MgSO4·7HO-224220.25g/L,接种量10%,发酵开始时添加CaCO,装液量20%,L-乳酸产量可达100.8g/L;重复间歇发酵补料培养基3的主要成分为:葡萄糖80g/L,NHNO33g/L,KHPO40.075g/L,葡萄糖单位时间转化率为2.92%/h。42     

响应面法优化金针菇液体发酵培养基

采用四因素三水平的Box-Behnken中心组合设计进行响应面法分析,考查葡萄糖、蛋白胨、KH_2PO_4和果蔬汁添加量对金针菇液体发酵菌丝生物量的影响。结果表明,在金针菇深层液体发酵试验中,最优培养基质量分数为葡萄糖2.15%,蛋白胨0.38%,KH_2PO_40.27%,果蔬汁12.90%;在优化培养基组成的条件下,预测金针菇深层发酵菌丝体产量最大值达21.51 mg/m L,与实际测量值21.46 mg/m L在误差范围内。     

响应面法优化醋糟厌氧发酵制氢

依据响应面试验设计法,选取有机负荷(Food/Microbe,F/M)、固液比、初始pH值和发酵温度为考察因素,进行醋糟厌氧发酵制氢工艺优化试验。在分析各个因素的显著性和交互作用后,得出醋糟厌氧发酵制氢的最佳工艺条件为:F/M1.65,固液比16.90g/200mL,初始pH值6.02,发酵温度37.66℃;各因素的主效应关系为:初始pH值>F/M>固液比>发酵温度。建立的产氢量数学模型为Y=26.63+1.34x1+1.27x-6.74x-2.44x-6x-1.7x2x-22233432.35x3x4,该模型能解释91.60%的响应值变化,产氢量的预测值为32.91mL/gTS,验证值为33.73mL/gTS。理论值与验证值的复相关系数为0.9780,证明此模型是合理可靠的,可用于实际预测。     

皮状丝孢酵母Trichosporon cutaneum产油脂发酵培养基优化

对皮状丝孢酵母发酵产油脂培养基中的碳氮源种类及添加量、KH_2PO_4添加量、接种量等影响因素进行优化。试验表明,葡萄糖为最佳碳源,蛋白胨为最佳氮源,在葡萄糖40 g/L,蛋白胨1.33 g/L,KH_2PO_4质量浓度1.0 g/L,最佳接种量15%时,油脂得率可达到细胞干质量的62%,比优化前提高了50%。     

响应面法优化蛹虫草液体培养条件

研究了碳氮源种类及其浓度对蛹虫草液体培养的影响,得出葡萄糖和蛋白胨为蛹虫草培养的最佳碳氮源。利用响应面分析法,对葡萄糖浓度、蛋白胨浓度、培养时间3个因素进行优化,得到蛹虫草液体培养的最佳的培养条件为：葡萄糖浓度33.30g/L、蛋白胨浓度12.50g/L、发酵时间为8d,在此条件下菌丝体生物量达到18.05g/L,多糖产量为1.13g/L。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.