High‐performance of Agaricus blazei fungus for the biological pretreatment of elephant grass

Biological pre‐treatment seems to be promising being an eco‐friendly process, with no inhibitor generated during the process. The potential for elephant grass pre‐treatment with white degradation fungi Pleurotus ostreatus, Agaricus blazei, Lentinula edodes, Pleurotus citrinopileatus, and Pleurotus djamor, in isolated or mixed cultures of these strains, was evaluated. The highest activities of enzymes involved in the degradation of lignocellulosic biomass (laccases, endoglucanases, xylanases, and β‐glucosidases) were observed for A. blazei, L. edodes and the combination of P. ostreatus and A. blazei. In the enzymatic hydrolysis, there was greater release of reducing sugars in the pre‐treated elephant grass samples by A. blazei during 10 days (338.91 ± 7.39 mg g^?1 of biomass). For this sample, higher lignin reductions, 24.81 and 57.45%, after 15 and 35 days of incubation, respectively, were also verified. These data indicate the potential of macromycetes such as A. blazei to perform biological pre‐treatments. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:42–50, 2018     

DoRGaN: Development of Quality Assurance and Quality Control Systems for High Dose Rate Brachytherapy Based on GaN Dosimetry Probes

Background

Safe High Dose Rate Brachytherapy (HDR-BT) requires quality assurance/quality control (QA/QC) according to IPEM and ESTRO recommendations. Recent advances in real-time dosimetry and related developments of QA, QC and in vivo dosimetry (IVD) systems have offered new possibilities for effective independent treatment verification, and thus for improving the patient safety.

Direct somatic embryogenesis through thin cell layer culture in Panax ginseng

Direct somatic embryos were differentiated on cotyledon transverse Thin Cell Layers (tTCLs) of Panax ginseng after 9 weeks in the Murashige and Skoog basal (MS) medium containing 2,4-d (5M). When MS medium containing 2,4-d (5M) was used for seedling pretreatment and for tTCLs culture, somatic embryos were observed 2 weeks earlier, i.e. after 7 weeks of culture. On the tTCLs from seedlings pretreated with 2,4-d (5M) combined with benzyladenine and zeatin at 0.1 M (BZ), somatic embryos were observed after 6 weeks of culture and the percentage of embryogenesis was higher (62%) than when 2,4-d was used alone for pretreatment (40%). Similar results were also obtained from pretreatment with combinations of 2,4-d (5M) and thidiazuron (TDZ) (0.01, 0.1M). When a combination of 2,4-d (5M) and BZ (0.1M) was used both for seedling pretreatment and for tTCLs culture, both somatic embryos and shoots were observed after only 3 weeks. As the concentration of BZ increased, the percentage of somatic embryogenesis decreased but the percentage of organogenesis increased. Similar responses were obtained with a combination of 2,4-d (5M) and TDZ (0.01M). On the medium containing both NAA (0.3M) and BZ (1M), globular- and heart- stage embryos developed after 4 weeks of culture into cotyledonary-staged embryos which remained dormant after a short elongation of the embryo axis. The importance of seedling pretreatment by growth substances in enhancing somatic embryogenesis is reported.Abbreviations BA 6-benzyladenine - BZ combination of BA and zeatin - 2,4-d 2,4-dichlorophenoxyacetic acid - MS medium Murashige and Skoog basal medium - NAA a-naphthaleneacetic acid - TDZ thidiazuron - tTCLs transverse thin cell layers - TCL longitudinal thin cell layer     

不同处理对海甘蓝种子发芽和幼苗生长的影响

由于受种子生理休眠作用的影响和硬而厚的种皮所产生的抑制作用,使海甘蓝（ＣｒａｍｂｅｍａｒｉｔｉｍａＬ．）种子发芽慢,发芽率低。为探索加快海甘蓝种子发芽和提高种子发芽率的有效方法,我们先后进行了８种不同的种子预处理试验和６种不同次氯酸钠溶液浸种的发芽试验。结果发现：（１）种子剥皮处理可以很大程度地促进发芽和提高发芽率;（２）用浓度为０．０５％的赤霉酸溶液浸种１８ｈ对海甘蓝种子发芽也有很好的促进作用;（３）用０．２０％的代森锰锌４５Ｍ（Ｄｉｉｔｈａｎｅ４５Ｍ）溶液浸种２０ｍｉｎ的消毒处理对海甘蓝种子发芽产生一定程度的抑制作用,但可减少海甘蓝幼苗死亡率;（４）适宜浓度的次氯酸钠漂白水（法文名１＇ＥａｕｄｅＪａｖｅｌ）的溶液（１０％）浸种５ｍｉｎ对促进海甘蓝种子发芽和减少幼苗死亡均有良好效果;浓度低于１０％时．不足以腐蚀种子硬而厚的种皮而促进种子发芽,也不足以杀死种子携带的病菌而减少幼苗死亡率;浓度大于１０％时,对种子的胚和种子内的酶活性产生不良影响,从而抑制种子发芽和影响幼苗的正常生长。     

Variability in maturation and germination from white spruce somatic embryos,as affected by age and use of solid or liquid culture

Summary The yield of morphologically normal Stage 3 somatic embryos of white spruce [Picea glauca (Moench) Voss], and subsequent germinability, was affected by culture age and use of solid and/or liquid culture growth conditions. Of the conditions that were compared, best results were obtained with cultures up to 3 yr old that had been continuously grown in liquid medium. Such material yielded up to 374 morphologically normal Stage 3 embryos per g f. wt. inoculum, when routinely pretreated using a 1 wk 2,4-dichlorophenoxyacetic acid-free period before maturation. By comparison the continual use of solid culture conditions resulted in lower yields (5/g f. wt. inoculum), and the use of solid medium in combination with liquid medium showed a greater affect of age on the production of normal Stage 3 embryos (348/g f. wt at 1.5 yr down to 19/g f. wt. at 3 yr) over the age range tested. In the absence of culture pretreatment, the oldest liquid cultures yielded only 44 normal Stage 3 embryos/g f. wt. inoculum, and the comparable solid to liquid cultures yielded 1.3/g f. wt. inoculum. The number of aberrant Stage 3 embryos in older cultures was reduced as a result of culture pretreatment; for example, in the oldest liquid cultures these represented 83% of the Stage 3 embryo population without pretreatment and 45% with pretreatment. Normal Stage 3 somatic embryo yield and germination characteristics (radicle and epicotyl development) were informative in distinguishing among the conditions studied. Germination characteristics were especially important when maturation responses were incapable of distinguishing among age classes. NRCC Contribution no. 38462.     

遗传学、优生学与伦理学试探A

遗传学、优生学与伦理学试探邱仁宗（中国社会科学院哲学研究所,北京１００７３２）ＡＰｒｅｌｉｍｉｎａｒｙＡｐｐｒｏａｃｈｔｏＧｅｎｅｔｉｃｓ,ＥｕｇｅｎｉｃｓａｎｄＥｔｈｉｃｓＱｉｕＲｅｎｚｏｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＰｈｉｌｏｓｏｐｈｙ,Ｃｈｉｎｅ...     

Mild alkaline/oxidative pretreatment of wheat straw

A new mild alkaline/oxidative pretreatment of wheat straw prior to enzymic hydrolysis was carried out. It consists of a first alkaline (1% NaOH for 24 h) step, which mainly solubilises hemicellullose and renders the material more accessible to further chemical attack, and a second alkaline/oxidative step (1% NaOH and 0·3% H₂O₂ for 24 h), which solubilises and oxidises lignin to minor polluting compounds. The entire process was carried out at low temperature (25–40°C) using a low concentration of chemicals, resulting in a relatively low cost and waste liquors containing only trace amounts of dangerous pollutants derived from lignin. Recovery of cellulose after the double pretreatment reached 90% of that contained in the starting material, with a concomitant 81% degradation of lignin. The action of a commercial cellulase on the cellulose obtained produced a syrup with a high concentration of reducing sugars (220 mg/ml), of which a large percentage was glucose.     

大麦花粉在低温预处理及培养中DNA含量的显微光度测定

大麦幼穗在低温条件(7℃)下,其花粉DNA的合成并未停止,但速度大为降低。花粉处于单核中期的幼穗,在最适预处理时期(14天)内其花粉DNA含量由1C增加到2C;而单核晚期的幼穗,其花粉通常在预处理期间分裂而形成营养细胞和生殖细胞。但与正常植株上的情况不同,约有60～70％花粉的营养细胞核的DNA合成也很快启动,致使在预处理结束时相当一部分花粉的营养细胞和生殖细胞的DNA均达到2C水平。 用经低温预处理过的幼穗的花药培养时,开始3～4天内形成的多细胞花粉其细胞核的DNA值多数保持在1～2C水平。但5～7天时在部分多细胞花粉中其核的DNA水平增加到2～4C,或4～8C。由同一多细胞花粉内不同细胞核的DNA值的差异可见已出现明显的混倍情况。     

Pretreatment of starch raw materials and their enzymatic hydrolysis by immobilized glucoamylase

The pretreatment of starch raw materials such as sweet potato, potato and cassava has been carried out using various types of crusher, viz juice mixer, homogenizer and high-speed planetary mill. The effect of pretreatment of the materials on their enzymatic hydrolysis was studied. High-speed planetary mill treatment was the most effective and comparable with heat treatment (pasting). Various crushing times were used to examine the effect of crushing by mill treatment on the enzymatic hydrolysis. In the enzymatic hydrolysis of cassava, the use of both cellulase [1,4-(1,3; 1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] and glucoamylase [1,4-α-d-glucan glucohydrolase, EC 3.2.1.3] enhanced the d-glucose yield. The immobilization of glucoamylase was studied by radiation polymerization of hydrophilic monomers at low temperature, and it was found that enzymatic activity of the immobilized glucoamylase particles varied with monomer concentration and particle size. Starchy raw materials pretreated with the mill can be efficiently hydrolysed by immobilized glucoamylase.     

低温预处理影响籼稻花药培养效率的研究

低温预处理使籼稻花药在培养初期退化花粉百分率低于对照;多核花粉百分率明显高于对照。经过低温预处理的花药来见新的可溶性蛋白谱带出现;淀粉酶同工酶谱带少和弱于对照,过氧化物酶同工酶中碱性区活性初期弱而后期强于对照。低温处理使药壁组织衰退进程有所延缓,但未能制止衰退,也未出现如粳稻中所见的药壁细胞充实发育的现象。低温预处理只能稍微延缓籼稻药壁组织的衰退进程,有限度地促进籼稻花药培养效率。