Phototropism in Hypocotyls of Radish : II. Role of cis- and trans-Raphanusanins, and Raphanusamide in Phototropism of Radish Hypocotyls

When etiolated radish (Raphanus sativus var. hortensis f. gigantissimus Makino) hypocotyls were subjected to a continuous unilateral illumination with white fluorescent light (0.1 watt per square meter), the growth rate at the lighted side was strongly inhibited for the first 2 hours, while that at the shaded side showed no change. After 2.5 hours growth on the lighted side recovered gradually, while that on the shaded side was slightly inhibited. The neutral growth inhibitors, cis- and trans-raphanusanins and raphanusamide, were determined in the lighted and shaded sides from 1 hour before until 2 hours after the start of unilateral illumination. In the lighted side, cis- and trans-raphanusanins increased by 0.5 hour after the start of illumination, reached 3 to 3.5-fold greater concentrations than in the shaded side after 1 hour, and then decreased gradually. Raphanusamide increased in the lighted side to a 3-fold greater concentration than that in the shaded one 2 hours after the start of the illumination. Unilateral applications of cis- and trans-raphanusanins and raphanusamide suppressed the growth of the hypocotyl on the applied side more than that on the opposite one, causing the hypocotyls to bend towards the site of application. The data suggest that phototropic curvature in radish is caused by the light-induced synthesis of growth-inhibiting cis- and trans-raphanusanins, and raphanusamide at the site of illumination.     

Phototropism in Hypocotyls of Radish : III. Influence of Unilateral or Bilateral Illumination of Various Light Intensities on Phototropism and Distribution of cis- and trans-Raphanusanins and Raphanusamide

When etiolated radish (Raphanus sativus var. hortensis f. gigantissimus Makino) hypocotyls were subjected to a continuous unilateral illumination with white fluorescent light at 0.05, 0.1, or 1 watt per square meter, the suppression of the growth rate on the lighted side depended on the light intensity. The growth rate at the shaded side was only a little affected by the illumination at 0.05 and 0.1 watt per square meter but considerably suppressed by that at 1 watt per square meter. Upon a continuous unequal bilateral illumination, the growth rate was more strongly suppressed on the side of the higher intensity than on the side of the lower one, resulting in phototropic curvature toward the light source of the higher intensity. It was calculated from correlation analysis of light intensity and growth rate that, on an average, 6.9% of the irradiation applied to one side reached the opposite side. The amounts of cis- and trans-raphanusanins and raphanusamide in hypocotyls subjected to unilateral or unequal bilateral illumination increased much more at the side of the lighted or the higher intensity than at the opposite side. The present study demonstrates that phototropism in radish hypocotyl is correlated with and we conclude caused by a gradient of growth inhibition in the hypocotyl, depending on irradiation-induced amounts of cis- and trans-raphanusanins and raphanusamide.     

Phototropism in Hypocotyls of Radish: IV. Flank Growth and Lateral Distribution of cis- and trans-Raphanusanins in the First Positive Phototropic Curvature

The first positive phototropic curvature induced by a pulse of unilateral white irradiation (0.1 watt per square meter, 30 seconds) of etiolated and de-etiolated Sakurajima radish (Raphanus sativus var hortensis f. gigantissimus Makino) hypocotyls was analyzed in terms of differential growth and growth inhibitor contents of the hypocotyls. In both etiolated and de-etiolated hypocotyls, the growth rates at the lighted sides were suppressed whereas those at the shaded ones showed no change. De-etiolation treatment induced a larger difference between the growth rates at the lighted and shaded sides of the hypocotyls, resulting in a larger curvature of de-etiolated seedlings than of etiolated ones. The contents of growth inhibitors, cis- and trans-raphanusanins, increased in the lighted but not in the shaded halves of the hypocotyls of etiolated seedlings. In de-etiolated seedlings, the two inhibitors increased due to the de-etiolation treatment. When de-etiolated seedlings were exposed to a pulse of unilateral irradiation the level of the two inhibitors remained high along the lighted side for 1 h following the light pulse, whereas at the shaded side the contents of the inhibitors abruptly decreased upon transfer to the dark, the difference between their amounts in the lighted and shaded sides being larger than in etiolated seedlings. Another growth inhibitor, raphanusamide, did not respond to the phototropic stimulus, although its amounts increased by the de-etiolation treatment. These data suggest that cis- and trans-raphanusanins are involved in the first positive phototropic response of radish hypocotyls, and that de-etiolation magnifies the phototropic response through induction of a larger lateral gradient of the raphanusanins in the hypocotyls by the phototropic stimulus.     

PHOT2介导拟南芥下胚轴向光弯曲调节子的筛选与鉴定

向光素(PHOT1和PHOT2)功能冗余调节单侧强蓝光诱导的拟南芥(Arabidopsis thaliana)黄化苗下胚轴向光弯曲表现功能冗余,限制了人们对PHOT2信号转导机制的深入研究。通过化学诱变剂甲基磺酸乙酯(EMS)诱变拟南芥phot1突变体,避开PHOT1基因的干扰,寻找PHOT2下游信号分子。研究结果表明,已成功筛选到1株遗传稳定的下胚轴向蓝光不弯曲突变体。遗传分析结果显示,该突变体可能是PHOT2下游信号分子突变,将其命名为p2sa1(phototropin2 signaling associated1)。用100μmol·m–2·s–1强蓝光单侧照射,phot1p2sa1下胚轴向光弯曲缺失,呈现phot1phot2双突变的表型,然而phot1p2sa1在强蓝光下叶绿体避光正常,明显不同于phot1phot2。实验证实P2SA1可能位于PHOT2的下游,参与调节PHOT2介导的拟南芥下胚轴向光弯曲反应。     

Isolation,Identification and Biological Activities of Growth Inhibitors in Peanut

Three acidic growth inhibitors were isolated from leaves of peanut and were identified as ferulic acid, p-cumaric acid and salicylic acid, respectively.     

Growth Regulators in Populus tremula I. Distribution of Auxin and Growth Inhibitors

The content of acid ether-soluble auxins and inhibitors in vegetative tissues of aspen (Populus tremula L.) was determined with the Avena coleoptile straightgrowth assay. A growth promotor, tentativety identified as indol-3-yl-acetic acid, occurred in highest concentration in the growing stem parts. It was also detected in various parts of the roots. Large amounts of inhibitors (inhihitor β) were found in growing stem tissue and in upper mature stem parts. Considerably lower content of inhibitors was found in leaves, in the basal stem part and in the roots. Nonwoody growing roots and the wood of older root segments, especially, contained very smalt quantities of inhibitors. The elution volume of a part of the inhibitory activity on a Sephadex column was similar to that of abscisic acid.     

花魔芋球茎发芽抑制物质的提取、分离与鉴定

从休眠花魔芋球茎中获得挥发性、酸性、酚类、碱性和中性５类提取物,分别用它们及其硅胶薄层层析带处理小白菜种子和已解除休眠的魔芋种子,其中酸性提取物对两种种子发芽均有显著的抑制作用。酸性提取物用ＤＥＡＥ－纤维素柱层析和硅胶薄层层析分离纯化,气谱－质谱联用仪鉴定含有脱落酸、阿魏酸和油酸。用其外源有机酸溶液分别处理已解除休眠的魔芋球茎,ＡＢＡ和阿魏酸对球茎顶芽萌发及生长有明显的抑制作用。     

Isolation of Acidic Growth Inhibitors in Dwarf Peas

Fumaric, palmitic, oleic and abscisic acids and methyl and ethyl hydrogen succinates were isolated from seedlings of dwarf pea (Pisum sativum L., var. Progress No. 9), grown under red light, as growth inhibitors which interfered with the responses of these plants to GA₃. Of the six compounds, fumaric acid did not show any inhibitory effect on stem elongation in the absence of GA₃.     

Isolation of Neutral Growth Inhibitors in Dwarf Peas

From seedlings of dwarf pea (Pisum sativum L., var. Progress No. 9) grown under red light, three neutral growth inhibitors were isolated which interfered with the responses of these plants to GA₃. The compounds were identified as β-sitosterol, α-stearoyl glycerol and pisatin, of which the glyceride produced remarkable inhibition when applied to terminal buds. Though its anti-gibberellin activity was not very strong, pisatin produced inhibition of the straight-growth of Avena coleoptile segments caused by IAA.     

Identification,Isolation and Expansion of Myoendothelial Cells Involved in Leech Muscle Regeneration

Adult skeletal muscle in vertebrates contains myoendothelial cells that express both myogenic and endothelial markers, and which are able to differentiate into myogenic cells to contribute to muscle regeneration. In spite of intensive research efforts, numerous questions remain regarding the role of cytokine signalling on myoendothelial cell differentiation and muscle regeneration. Here we used Hirudo medicinalis (Annelid, leech) as an emerging new model to study myoendothelial cells and muscle regeneration. Although the leech has relative anatomical simplicity, it shows a striking similarity with vertebrate responses and is a reliable model for studying a variety of basic events, such as tissue repair. Double immunohistochemical analysis were used to characterize myoendothelial cells in leeches and, by injecting in vivo the matrigel biopolymer supplemented with the cytokine Vascular Endothelial Growth Factor (VEGF), we were able to isolate this specific cell population expressing myogenic and endothelial markers. We then evaluated the effect of VEGF on these cells in vitro. Our data indicate that, similar to that proposed for vertebrates, myoendothelial cells of the leech directly participate in myogenesis both in vivo and in vitro, and that VEGF secretion is involved in the recruitment and expansion of these muscle progenitor cells.     

萝卜乙烯合成途径基因的鉴定及对胁迫的响应

该研究通过生物信息学方法,对萝卜(Raphanus sativus L.)乙烯合成途径关键结构基因(MAT、ACS和ACO)家族成员进行鉴定,并利用转录组数据和荧光定量方法探究其组织表达和对生物及非生物胁迫的响应。结果表明:(1)萝卜基因组中包含8个MAT、16个ACS和7个ACO基因,均可分为3个亚家族。(2)这些基因启动子中至少含有1个光响应顺式作用元件;除ACO1.1和ACO3外,其余基因启动子中均至少含有一种响应植物激素的顺式作用元件;多个基因启动子中含有响应生物及非生物胁迫的顺式作用元件。(3)转录组数据分析发现,萝卜所有MAT、ACS6.1和ACO2/3/4在叶片中均具较高的表达量;根癌农杆菌侵染诱导抗病萝卜的MAT2-4、ACS2/7.1/7.2和ACO1.1/1.2/4显著上调表达,而感病材料多个基因下调表达;铅、镉和铬胁迫均显著促进MAT4.2和ACO1.1/4的表达,但抑制MAT1和ACO5.1的表达;4℃低温显著抑制MAT2.1/2.2/4.1和ACO1.1/5.2的表达。(4)qRT-PCR分析表明,NaCl和PEG-6000均显著促进ACO5.1/5.2的表达,但抑制MAT4.1和ACO4的表达;果糖和蔗糖可能参与了萝卜对PEG-6000胁迫的响应。该结果为研究萝卜乙烯合成途径基因家族成员的功能奠定了基础。     

萝卜色素的分离、纯化及其性质研究

“心里美”萝卜酒精提取物,经薄层层析、高压液相层析纯化后可得到天然色素为粉红色针状结晶。该色素性质稳定、耐温、耐光,颜色随pH值的不同而变化。经红外光谱分析和质谱鉴定,初步推导其结构可能为报春花色素。     

西洋参果实中抑制白菜种子发芽物质的分离与鉴定

改进了传统的发芽抑制物质的提取、分离与鉴定方法,以系统溶剂法初步提取各组分,通过TLC分离与纯化,用GC－MS联用仪进一步分离鉴定,最后以标准品核对并测定抑制物质的活性及半抑制浓度（IC50）。首次从西洋参果实中分离鉴定出水合三氯乙醛。己酸和辛酸3种发芽抑制物质,其半抑制浓度分别为577．6、128．4和87．7μl／L。     

Pollen Tube Growth Inhibitors Involved in the Ovary of Self-Incompatible Japanese Pear

The growth inhibitors of pollen tubes in the pistils of Japanesepear ‘Chojuro’ were studied in vitro to elucidatethe physiological mechanism of self-incompatibility. Addition of water extracts from ovaries into a well dug in anagar medium containing sucrose and boric acid inhibited thegrowth of incompatible pollen tubes more strongly than thatof compatible ones. The substance, tentatively called Sinhibitor(self-inhibitor), was detectable in a relatively wide rangeof concentrations of the extract, from 10- to 60-fold dilution.However, it was absent in the stylar extract. S-inhibitor was stable, even though the extract was heated to100?C for 10 min. The chromatogram of the S-inhibitor followinga Sephadex G-10 gel filtration showed 2 peaks of inhibition:one peak corresponded to the peaks of protein and phenol (phenolsmay be conjugated with proteins), and the other to that of reducingsugar. The water extract from mature ovaries when diluted 10-fold wasa stronger growth inhibitor of incompatible pollen tubes comparedwith that from immature ones. This substance, tentatively calledA-inhibitor (adult-inhibitor), appeared to be different fromS-inhibitor. (Received May 20, 1986; Accepted December 22, 1986)     

Properties of Higher Plant Mitochondria. I. Isolation and Some Characteristics of Tightly-coupled Mitochondria from Dark-grown Mung Bean Hypocotyls

The mitochondria isolated from dark-grown mung bean hypocotyls oxidize succinate, l-malate, and externally added reduced nicotine adenine dinucleotide (NADH) with good respiratory control. While the pattern of respiration resembles that of animal mitochondria, there are 4 basic differences between the respiratory properties of mung bean and animal mitochondria: A) the ability to oxidize NADH, B) the pattern of succinate and malate oxidation, C) the rate of oxygen uptake, and D) the adenosine-5′-diphosphate to oxygen ratios.     

1株产纤维素酶细菌的筛选、鉴定及生长特性

分离筛选高效降解纤维素的菌株,并研究其生物学特性。利用刚果红染色法从腐烂的玉米秸秆中分离纤维素降解菌,再通过测定滤纸的降解率及多种酶活复筛。综合考虑水解圈和菌落直径(HC值),滤纸的降解率和酶活,对所筛选的菌株进行纤维素降解能力综合评价,最终获得1株具有纤维素降解能力的菌株DX4,其滤纸酶活(FPA酶活)、内切葡聚糖酶活力(CMC酶活)和外切葡聚糖酶活力(Cex酶活)分别为256.051、358.276和5.536 U/m L。结合形态学、生理生化特性和分子生物学鉴定,将该菌株鉴定为枯草芽胞杆菌(Bacillus subtilis),命名为Bacillus subtilis DX4,简称BS-DX4。研究表明,BS-DX4的最适生长温度为40℃,最适生长pH为7.0,低盐浓度下生长旺盛,是具有开发潜力的纤维素酶高产菌株。     

Isolation and Identification of Spawning Inhibitors from Ovaries of the Starfish,Asterias amurensis

An extracellular alkaline proteinase produced by Candida lipolytica was purified through iso-propanol and ammonium sulfate precipitation, decolorization with DEAE-cellulose, gel filtration with Sephadex G–100 and ion-exchange chromatography on DEAE-Sephadex A–50. The optimum pH of its caseinolytic activity was 9.0, and this activity was completely inactivated with DFP but not with chelating reagents, PCMB, STI, TLCK, TPCK, or SSI. This enzyme also hydrolyzed salmin and synthetic esters, such as Bz. Arg. OEt, Bz. His. OMe, Tos. Lys. OMe or Ac. Tyr. OEt, and the optimum pH of its esterase activity was 8.0. The molecular weight of the enzyme was estimated to be about 30,000 by the gel filtration method. These facts indicated that this enzyme was distinguishable from other microbial alkaline proteinases so far studied.     

New Late Gene, dar, Involved in DNA Replication of Bacteriophage T4 I. Isolation, Characterization, and Genetic Location

Suppressors of gene 59-defective mutants were isolated by screening spontaneous, temperature-sensitive (ts) revertants of the amber mutant, amC5, in gene 59. Six ts revertants were isolated. No gene 59-defective ts recombinant was obtained by crossing each ts revertant with the wild type, T4D. However, suppressors of gene 59-defective mutants were obtained from two of these ts revertants. These suppressor mutants are referred to as dar (DNA arrested restoration). dar mutants specifically restored the abnormalities, both in DNA synthesis and burst size, caused by gene 59-defective mutants to normal levels. It is unlikely that dar mutants are nonsense suppressors since theý failed to suppress amber mutations in 11 other genes investigated. The genetic expression of dar is controlled by gene 55; therefore, dar is a late gene. The genetic location of dar has been mapped between genes 24 and 25, a region contiguous to late genes. dar appears to be another nonessential gene of T4 since burst sizes of dar were almost identical to those of the wild type. Mutations in dar did not affect genetic recombination and repair of UV-damaged DNA, but caused a sensitivity to hydroxyurea in progeny formation. The effect of the dar mutation on host DNA degradation cannot account for its hydroxyurea sensitivity. dar mutant alleles were recessive to the wild-type allele as judged by restoration of arrested DNA synthesis. The possible mechanisms for the suppression of defects in gene 59 are discussed.     

氰戊菊酯降解菌FDB的分离鉴定及其生长特性

从长期受农药污染的农田土壤中分离筛选到一株降解氰戊菊酯杀虫剂的细菌菌株FDB。经形态和生理生化特征鉴定以及对16SrDNA序列进行同源性比较,将该菌株鉴定为铜绿假单胞菌Pseudomonas aeruginosa。FDB能以氰戊菊酯杀虫剂为唯一碳源生长,在30°C培养5d对100mg/L氰戊菊酯异构体的降解率分别达到69.06%(SR+RS)和64.32%(SS+RR)。FDB的最适生长条件为:温度35°C,初始pH值7.0,250mL摇瓶装液量75mL。采用超声波方法破碎菌体细胞,得到粗酶液。胞内和胞外粗酶液对氰戊菊酯异构体的降解试验表明,FDB的氰戊菊酯降解酶属于胞内蛋白组分。     

通过cDNARDA法分离和识别盐藻(Dunaliella salina)盐胁迫相关基因

采用cDNA代表性差异分析 (RDA)技术 ,对盐藻在盐胁迫时差异表达的基因进行了分离鉴定 .在分离到的 10个基因中 ,有 5个与已知基因同源 (包括叶绿素a b结合蛋白基因、蛋白磷酸酶I催化亚基基因和 3个核糖体蛋白基因 ) ,还有 5个未知功能基因则是首次在盐藻中被分离 .值得注意的是 ,所有这 5个已知基因的功能都与细胞分裂或盐胁迫有关 .结果表明 :取样时盐藻细胞仍处于恢复阶段 ,所分离到的基因对于盐藻耐盐可能具有重要意义 ;蛋白磷酸酶I的下调表达可能是盐藻调节离子平衡的一个重要过程和细胞分裂受阻的原因所在 ;盐藻减缓细胞分裂速度可能是为了减少能量消耗 ,以留出足够的能量来应对盐胁迫 ;其它 5个未知基因可能也与盐藻适应盐胁迫机制有关 .