亚麻脱胶新工艺的初步研究

研究了温水浸渍亚麻脱胶过程中的产果胶酶的微生物数量、种类和果胶酶活力变化规律,分离筛选出了产果胶酶活力较高的厌氧和兼性厌氧菌各l株,研究了这2个菌株的种子培养条件,用正交实验法优化了接入厌氧和兼性厌氧菌的亚麻脱胶工艺.实验结果表明亚麻脱胶周期缩短35%,可改善麻纤维质量.     

亚麻脱胶过程中细菌学、酶学及相关参数分析

在实验室条件下对亚麻原茎进行温水脱胶,系统分析发酵过程中细菌总数、果胶菌、果胶酶、木聚糖酶、纤维素酶、还原糖、总氮量、pH值及COD等参数的动态变化.同时,采用变性凝胶电泳(DGGE)技术探讨了亚麻脱胶过程的生物多样性.     

亚麻纤维脱胶菌的筛选及脱胶效果研究

为筛选亚麻纤维脱胶菌株,从麻脱胶废水、废麻堆积物等7个含麻胶质样品中分离得到39株能分解果胶的菌株.采用水解圈法复筛选出8株果胶酶活性较高的菌株,经果胶酶、纤维素酶活性测定和菌体脱胶试验,最终确定8-1是优良的亚麻脱胶菌株,该菌株果胶酶活可达663.17 u/mL,而纤维素酶活仅为9.13 u/mL.菌株8-1经形态观察、Biolog菌种鉴定系统鉴定以及基于16S rDNA序列构建的系统进化树分析为一株芽孢杆菌.     

大鲵油的水酶法提取及精制过程中脂肪酸组成的变化

为研究大鲵油脂肪酸的营养价值,通过水酶法提取大鲵油,采用气相色谱-质谱法(GC-MS)分析粗大鲵油及其精制(脱胶、脱酸、脱臭)过程中脂肪酸组成的变化以及精制草鱼油中脂肪酸组成的差异。研究结果表明:水酶法提取大鲵油的最佳条件为酶解温度60℃,pH6.5,酶添加量0.75%,酶解时间90 min。所得粗大鲵油达到SC/T 3502-2016粗鱼油二级标准。研究发现,在粗大鲵油中共检出脂肪酸20种,精制过程中脂肪酸组成基本不变,精制后大鲵油中不饱和脂肪酸和必需脂肪酸的相对含量分别达74.76%和25.17%,均高于精制草鱼油中不饱和脂肪酸(61.08%)与必需脂肪酸(18.90%)的相对含量,由此可知,当前方法对大鲵油的提取较为有效,且大鲵油营养价值较草鱼油高。     

木聚糖酶生产现状研究

木聚糖酶(xylanase)是一种广为所知的工业用酶制剂,在造纸、食品、饲料工业、亚麻脱胶、燃料生产等工业中有广泛应用。本文详细介绍了木聚糖酶的酶学性质、微生物生产木聚糖酶的诱导物以及生产发展现状等方面。     

亚麻脱胶菌种的选育及脱胶过程的初步研究

从沤麻主生物期的水中分离产果胶酶的菌株经初筛、复筛获得了三株专性厌氧细菌,初步鉴定为费氏芽孢杆菌,对其亚麻脱胶性能进行了初步研究,确定人工加菌沤麻的最适工艺条件为：加菌量2％,加菌时间：沤麻进入主生物期零时,菌株A优于其它菌株．结果表明：采用上述工艺进行沤麻实验,可缩短沤麻时间30％,并可提高麻纤维质量。     

亚麻微生物脱胶优势菌的选育及其应用

从亚麻种植土壤与沤麻水中分离出96株能分解果胶的菌株。通过初筛和复筛获得4株果胶酶高产菌株。其中,在果胶平板培养基上生长速度快、产果胶酶活力高的12号菌株被确定为优势菌,经鉴定其为枯草芽孢杆菌。最适脱胶条件为：麻水比1：15,pH7．5,温度32～33℃,预培养的优势菌接种量3％。结果表明,采用优势菌的脱胶周期比对照缩短50％左右,而且麻的纤维质量明显得以改善。     

ISAAA信息

<正>转基因亚麻产生大量OMEGA-3脂肪酸洛桑研究所的研究人员成功地对亚麻(Camelina sativa)种子的新陈代谢途径进行了改造,并使得其十二碳五烯酸(EPA)和二十二碳六烯酸(DHA)的产量达到了12%和14%,这个组成比例     

ISAAA信息

<正>转基因亚麻产生大量OMEGA-3脂肪酸洛桑研究所的研究人员成功地对亚麻(Camelina sativa)种子的新陈代谢途径进行了改造,并使得其十二碳五烯酸(EPA)和二十二碳六烯酸(DHA)的产量达到了12%和14%,这个组成比例     

果胶酶在麻类脱胶中的应用及其作用机理

脱胶是麻类产业链中的难题。生物脱胶则是解决麻类加工技术难题的发展方向。果胶酶在生物脱胶中的应用一直是研究的重点。本文通过分析国内外有关果胶酶和产酶微生物在选育、发酵、酶学性质、基因工程与脱胶工艺等方面的研究进展,阐明了果胶酶在麻类脱胶中的作用机理。果胶酶是麻类生物脱胶不能缺少的关键酶之一,但不能独立完成麻类脱胶;根据麻类纤维原料特性,采用基因操作等技术构建复合酶高产菌株是未来的重点研究方向。     

Genome-wide analysis of genomic imprinting in the endosperm and allelic variation in flax

Genomic imprinting is an epigenetic phenomenon that causes biased expression of maternally and paternally inherited alleles. In flowering plants, genomic imprinting predominantly occurs in the triploid endosperm and plays a vital role in seed development. In this study, we identified 248 candidate imprinted genes including 114 maternally expressed imprinted genes (MEGs) and 134 paternally expressed imprinted genes (PEGs) in flax (Linum usitatissimum L.) endosperm using deep RNA sequencing. These imprinted genes were neither clustered in specific chromosomal regions nor well conserved among flax and other plant species. MEGs tended to be expressed specifically in the endosperm, whereas the expression of PEGs was not tissue-specific. Imprinted single nucleotide polymorphisms differentiated 200 flax cultivars into the oil flax, oil-fiber dual purpose flax and fiber flax subgroups, suggesting that genomic imprinting contributed to intraspecific variation in flax. The nucleotide diversity of imprinted genes in the oil flax subgroup was significantly higher than that in the fiber flax subgroup, indicating that some imprinted genes underwent positive selection during flax domestication from oil flax to fiber flax. Moreover, imprinted genes that underwent positive selection were related to flax functions. Thirteen imprinted genes related to flax seed size and weight were identified using a candidate gene-based association study. Therefore, our study provides information for further exploration of the function and genomic variation of imprinted genes in the flax population.     

The effects of dietary flaxseed on the Fischer 344 rat: I. Development, behaviour, toxicity and the activity of liver gamma-glutamyltranspeptidase

The effect of exposure to, followed by consumption of, 10% flax chow from the 18th day of gestation to the 86th day after birth was examined in male and female Fischer 344 rats. Growth curves of the flax chow-fed rats were identical to those of regular chow-fed rats, as were such developmental milestones as pinna development, growth of hair and eye opening. Acoustical startle and the righting reflexes, developmental behavioural indices, were also the same. Blood glucose levels were comparable in flax chow-fed and regular chow-fed rats at all stages of development, indicating that flax is without effect on glucose balance. There were no signs of toxicity in the flax chow-fed rats since their plasma levels of alanine aminotransferase and gamma-glutamyltranspeptidase (gammaGT) were the same as those of regular chow-fed rats. The activity of gammaGT displayed an increase in the livers of flax chow-fed rats after puberty, more so in the male-four-fold-than in the female-1.38-fold. This is suggestive of an estrogenic effect which implicates an effect of an estrogenic flax lignan. An hepatobeneficial effect of the flax-induced increase in liver gammaGT is discussed. In summary, dietary 10% flax chow is without long-term effect on growth, development and behaviour, is non-toxic and may be hepatoprotective.     

胡麻资源萌发期耐盐综合性评价

筛选胡麻耐盐品种,对胡麻产业可持续发展应对盐渍胁迫具有重要现实意义。试验选用100 mmol·L^-1的NaCl溶液对28份胡麻资源种子进行胁迫,并测定发芽率、总鲜重、下胚轴鲜重、下胚轴干重、下胚轴长、胚根鲜重、胚根干重和胚根长等相关指标,通过相关性分析、因子和主成分分析、聚类分析和逐步回归分析对11个指标进行综合分析,对28份胡麻资源萌发期耐盐性做出评价,并筛选出胡麻萌发期耐盐性鉴定的关键指标。结果表明：经相关分析,11个指标中多项指标间都是极显著或显著的正相关;因子和主成分分析将11个单项指标转化成3个综合指标,第Ⅰ主成分为下胚轴长势情况,第Ⅱ主成分为胚根长势情况,第Ⅲ主成分为种子萌发情况;聚类分析将28份胡麻资源划分为4大类：耐盐型、中等耐盐型、盐敏感型和强盐敏感型。雁杂10号、轮选1号为强耐盐材料;陇亚4号、R40号、DYMS为较强耐盐材料;逐步回归分析建立了胡麻萌发期耐盐能力预测的数学评价模型,筛选出总鲜重、胚根干重、发芽指数和下胚轴长这4个鉴定指标是胡麻萌发期耐盐能力鉴定的关键指标。以这4个筛选指标计算出的预测值与综合评价计算出的综合Z值之间极显著相关（R²=0.991 8^**）,表明鉴定结果具有较高的准确性,可以代替原来11个指标对胡麻萌发期耐盐性进行评价。     

亚麻荠对小菜蛾幼虫取食和成虫行为反应的影响

亚麻荠是一种很少有害虫危害的油料作物。用室内生测和Y 型嗅觉仪研究了亚麻荠对小菜蛾Plutella xylostella幼虫取食和成虫行 为反应的影响。以甘蓝作对照,用亚麻荠叶片喂养的小菜蛾初孵幼虫3天后校正死亡率为79 .2%,显示了较强的致死作用;喂养小菜蛾3龄幼虫至化蛹,其存活率、化蛹率、蛹重及成 虫寿命都显著降低,表明亚麻荠对小菜蛾幼虫的生长发育有不利影响。在幼虫的取食选择实 验中,有甘蓝叶供选择时,小菜蛾幼虫不取食亚麻荠;在无可选择的情况下,小菜蛾幼虫也 取 食亚麻荠叶片,但取食量很小,与取食甘蓝叶的量相比,差异极显著。行为反应测试表明, 小菜蛾成虫对甘蓝和亚麻荠植株的挥发物都有明显的趋性反应,与对照（净化空气）相比, 差异极显著,而在甘蓝和亚麻荠之间无选择性。说明小菜蛾成虫对亚麻荠植株的挥发物具有 较强的定向反应。     

The effects of dietary flaxseed on the Fischer 344 rat: II. Liver gamma-glutamyltranspeptidase activity

The effect of 10% flax chow consumption from the 30th to the 130th day after birth was examined in male Fischer 344 rats. The effects of both the high lignan/high oil Norlin strain and a high lignan/low oil Solin strain of flaxseed were compared. Physically and behaviourally there were no differences in rats belonging to the three dietary groups at any time. At 50 and 100 days of dietary exposure, blood glucose levels were the same in Norlin and Solin flax chow-fed and as well as regular chow-fed rats; there were no signs of toxicity in the Norlin and Solin flax-fed rats since their plasma levels of alanine aminotransferase were the same and equal to those of regular chow-fed rats. The activity of gamma-glutamyltranspeptidase (gammaGT) displayed an increase in the liver homogenates of flax chow-fed rats. This increase was the same in Norlin and Solin flax-fed rats at 50 and 100 days. Thus the liver effect was not oil, but lignan, likely secoisolariciresinol diglucoside (SDG), induced and was effected early on, and sustained, after flax exposure. The degree of heat activation of liver homogenate gammaGT was the same in regular chow-fed and flax chow-fed rats. Compared to liver homogenate gammaGT activity, the soluble form of gammaGT was expressed at very low levels while the plasma membrane-bound form of gammaGT was expressed at very high levels in rat liver in both regular chow-fed and flax chow-fed rats. There was no effect of flax feeding on the soluble form of liver gammaGT which was expressed at a very low level. Flax feeding effected an increase in the activity of gammaGT in isolated plasma membrane fractions which mirrored that in liver homogenates: the same degree of increase was seen in Norlin flax chow-fed and Solin flax chow-fed rats. Flax consumption effects an increase in the activity of liver gammaGT at the level of the plasma membrane which is lignan dependent, physiologically relevant and may be linked to hepatoprotection against injury through an increase in reduced glutathione.     

Production of polysaccharide-degrading enzymes by saprophytic fungi from glyphosate-treated flax and their involvement in retting

The fungi present on glyphosate-treated flax plants were isolated. Cladosporium herbarum, Epicoccum nigrum, Botrytis cinerea and yeasts occurred most frequently immediately after glyphosate treatment but as retting progressed the frequency of occurrence of Fusarium culmorum, Alternaria alternata and a Phoma sp. increased. Many of the fungi isolated from retting flax were also present as epiphytes on healthy flax stems. Glyphosate was shown to be fungitoxic in vitro but it had only a very slight effect on fungi colonising the flax. The application of sucrose and urea to flax 1 wk after glyphosate treatment resulted in more rapid fungal colonisation of the stems, but did not significantly enhance retting. When grown on sterilised flax stem sections, fungi known to be saprophytic on flax produced polysaccharide-degrading enzymes. All seven fungi tested produced polygalacturonase, pectin-lyase and xylanase. The greatest cellulase activity was present in stem tissues inoculated with F. culmorum and the Phoma sp. while no cellulase was detected in tissue inoculated with B. cinerea, a Mucor sp. or a Penicillium sp. Extracts from flax inoculated with the cellulolytic fungi caused the solubilisation of native cellulose. Pectinases, xylanase and cellulase were also detected in naturally-colonised senescing and dead flax stems. Stems which had been treated with a sucrose solution tended to contain the greatest enzyme activity.     

The sealed storage of moist flax with and without the use of chemical preservatives

The suitability of ensilage as a means of preserving flax was investigated in a series of experiments in which 400 kg round bales of fresh flax were sealed in polyethylene film or plastic wrapped, with or without the addition of formic acid at 2.5 litre t^-1 or formalin at 5.6 litre t^-1 at the time of baling. Plastic wrapping provided a more effective seal than the bags which were easily punctured by the flax roots resulting in moulding and deterioration of the flax. Where the seal was not broken untreated flax underwent a clostridial fermentation and the pH fell to about 4.8. Cellulolytic activity degraded the flax fibre over a period of 3 to 6 months. The addition of formic acid reduced the cellulolytic activity provided the seal was not broken. In an experiment with 4 kg batches of flax of 65%, 40% or 25% MC sealed in polyethylene film, the addition of formic or propionic acids at 20 g kg^-1 DM did not prevent moulding and deterioration, but both NH₃ and SO₂ at 40 g kg^-1 DM preserved the physical structure of the flax. The NH₃ darkened the flax and made it pliable and unscutchable while the SO₂ bleached it and preserved the fibre without microbiological deterioration. The presence of acids on the moist stored flax appeared to inhibit the progress of normal water retting.     

Flax species polymorphism for isozyme and metabolic markers

Genetic diversity of flax isozyme patterns of 6-phosphogluconate dehydrogenase, glutamate-oxaloacetate transaminase, and cytochrome-c-oxidase in leaves, as well as the level and the relative amounts of fatty acids in seed oil were studied in flax species. The isozyme loci examined were found to be polymorphic. It was shown that each of the flax species studied was characterized by strictly defined amounts and proportions of fatty acids, i.e., the fatty acid composition of the seed oil may be used as a species diagnostic trait. Our results suggest that all of the flax species studied have the same ancestor. Linum grandiflorum was shown to be a phylogenetic branch split at an early stage of the flax evolution.     

Structural organization and classification of cytochrome P450 genes in flax (Linum usitatissimum L.)

Flax CYPome analysis resulted in the identification of 334 putative cytochrome P450 (CYP450) genes in the cultivated flax genome. Classification of flax CYP450 genes based on the sequence similarity with Arabidopsis orthologs and CYP450 nomenclature, revealed 10 clans representing 44 families and 98 subfamilies. CYP80, CYP83, CYP92, CYP702, CYP705, CYP708, CYP728, CYP729, CYP733 and CYP736 families are absent in the flax genome. The subfamily members exhibited conserved sequences, length of exons and phasing of introns. Similarity search of the genomic resources of wild flax species Linum bienne with CYP450 coding sequences of the cultivated flax, revealed the presence of 127 CYP450 gene orthologs, indicating amplification of novel CYP450 genes in the cultivated flax. Seven families CYP73, 74, 75, 76, 77, 84 and 709, coding for enzymes associated with phenylpropanoid/fatty acid metabolism, showed extensive gene amplification in the flax. About 59% of the flax CYP450 genes were present in the EST libraries.     

Botanical analysis of a bundle of flax (Linum usitatissimum L.) from an early medieval site in northern Poland; a contribution to the history of flax cultivation and its field weeds

A bundle of flax (Linum usitatissimum L.) radiocarbon dated to 1210±70 uncal B.P. (830±90 cal A.D.) was analysed for its macrofossil content. Apart from stems, capsules and seeds of flax., a large number of diaspores (fruits and seeds) from other plants was identified. Field weeds were the most numerous taxa present, among them three flax field weeds,Spergula maxima, Camelina alyssum andCuscuta cpilinum. Development of the specific flax weed community is discussed. Indicator values are used to characterize the edaphic conditions of this early medieval flax field. The field weeds spectrum also suggests that this flax was sown as a summer crop after an earlier crop of millet.