Alicyclic acid metabolism in plants 3. Fate of 14C-shikimate and 14C-quinate in mung bean plants

Young mung bean plants (Phaseolus mungo) were exposed to ¹⁴C-shikimateor ¹⁴C-quinate in the light. After 8 or 23.5 hr of incubationat 25°C, radioactivities in free and bound amino acids,organic acids, soluble and insoluble carbohydrates, ether-solublefraction and lignin were determined. Shikimic and quinic acidswere separated by the combined use of paper-chromatography andcolumn chromatography. Specific activity of formed quinate orshikimate was only slightly lower than that of fed shikimateor quinate. Specific activities of phenylalanine, tyrosine andbound tryptophan were high as compared with those of non-aromaticamino acids. Discussion is focused upon the interconversionbetween shikimate and quinate, and their roles in the biosynthesisof aromatic amino acids. (Received November 15, 1968; )     

2. Alicyclic acid metabolism in plants Enzymes related to the shikimate pathway in developing mung bean seedlings

A study was made of chages in the activities of enzymes relatedto the biosynthesis of aromatic compounds in etiolated mungbean seedlings during their growth. Shikimate: NADP oxidoreductaseactivity in the root-shoot axes increased rapidly to attainits highest activity the 4th day after sowing, and remainedat that level over the experimental period of 7 days. 5-Dehydroquinatehydro-lyase activity continuously increased for at least 7 days.In the cotyledons, a gradual decrease in the activities of theseenzymes occurred. Phenylalanine ammonia-lyase activity in root-shootaxes gradually increased showing a maximum on the 6th day. Thehighest specific activity, on a protein basis, of this enzymewas seen in the initial stage of growth. In the cotyledons,a rise in total activity appeared on the 2nd day. Tyrosine ammonia-lyaseactivity was very low as compared with phenylalanine ammonia-lyase.The enzyme activities of light-germinated seedlings were comparedto those of dark-germinated seedlings on the 7th day. Lighthad practically no significant effect on the appearance of shikimate:NADP oxidoreductase and 5-dehydroquinate hydro-lyase activities.On the other hand, a marked effect from the light on the riseof phenylalanine ammonia-lyase and tyrosine ammonia-lyase activitieswas found, especially in the epicotyl-plumules. The results are discussed with respect to the metabolism ofalicyclic acids such as shikimic acid in the developing mungbean seedlings. ¹This work was partly supported by a grant-in-aid from the Ministryof Education.     

香蕉果实XET cDNA的克隆及其在成熟软化的果实果皮和果肉中的表达分析

木葡聚糖内糖基转移酶(Xyloglucan endotransglycosylase,XET)通过分解细胞壁半纤维素多糖的主要成分--木葡聚糖而参与果实软化.为了阐明香蕉(Musa acuminata.Colla cv.GrandNain)果实成熟过程中的软化与细胞壁代谢酶XET基因表达模式的关系,采用RT-PCR和RACE-PCR方法,首次从成熟香蕉果实果肉中分离了编码XT基因的全长cDNA(MA-XET1,全长1 095 bp).序列分析表明,MA-XET1的5'端和3'端的非翻译区分别为66 bp和1 89bp,该片段含有一个完整的开放读码框,编码280个氨基酸,推导的MA-XET1蛋白质中存在XET蛋白的催化活性部位DEIDFEFL.Southern杂交表明,MA-XET1在香蕉基因组中由多拷贝基因编码.Northern分析显示,跃变前期的果肉中,不能检测MA-XET1基因的表达,跃变期的果实果肉中MA-XET1表达增加,跃变后期该基因表达略有减弱;在跃变前期的果实果皮中,MA-XET1的积累较低,跃变期的果实果皮中积累大幅增加,而后迅速下降.Propylene(丙烯,乙烯的类似物)处理降低香蕉果实果皮和果肉的硬度,而且propylene促进MA-XET1在果皮和果肉中的积累.这些结果表明,MA-XET1参与香蕉果实成熟过程中的果皮和果肉软化,并且,MA-XET1的表达在转录水平上受乙烯调控.     

L-Tyrosine carboxy-lyase of barley roots

_L-Tyrosine carboxy-lyase (E.C. 4. 1. 1. 25) was isolated fromroots of germinating barley (Hordeum vulgare). The enzyme requirespyridoxal phosphate for maximum activity. The optimum pH foractivity is about 7.0. The enzyme is inhibited by p-chloromercuribenzoateand hydroxylamine at 10^–3 M. Enzyme activity is foundin extracts from young roots, especially from those in earlystages of development, but not in extracts from shoots of thesame plant. Localization and changes in the amounts of _L-tyrosinecarboxy-lyase and aromatic amines in developing barley seedlingswere measured. Participation of carboxy-lyase in the formationof aromatic amines in barley roots is suggested. (Received July 17, 1970; )     

Comparative analysis of volatile components from labial glands of male Japanese bumblebees (Bombus spp.)

The volatile components from the labial glands of males of six Japanese bumblebee species were analyzed and compared. Clear species‐specificity was found. Ethyl dodecanoate was identified as the major component from the glands of Bombus (Bombus) hypocrita hypocrita and Bombus (Bombus) hypocrita sapporoensis while dihydrofarnesal and dihydrofarnesol were the major components from Bombus (Bombus) ignitus. Citronellol and trans,trans‐farnesol were found from Bombus (Pyrobombus) ardens ardens and Bombus (Diversobombus) diversus diversus, respectively. trans,trans‐Farnesol was also found from Bombus (Diversobombus) diversus tersatus in Hokkaido. Such differences strongly suggest that these chemicals play an important role in reproductive isolation between sympatric species of Japanese bumblebees.     

ELECTRON MICROSCOPE STUDIES ON SPERM DIFFERENTIATION IN MARINE ANNELID WORMS. I. SPERM FORMATION IN IKEDOSOMA GOGOSHIMENSE

The ultrastructur of spermatozoa and the changes through which they are differentiated during sperm formation in an echiuroid were observed under the electron microscope. Many spermatids are connected to one central cytoplasmic mass and the sperm differentiation proceeds synchronously in one sperm-ball. Dense plate-like structures appear in the cytoplasm of early spermatids and disappear soon. In the process of nuclear condensation, many electron-dense aggregates appear in homogeneously textured chromonema and the aggregates are packed together to form a uniformly dense nucleus. Near the centriole at the opposite side from the central mass, the mitochondria fuse together to form one large middle-piece mitochondrion and the acrosomal vesicle is formed from the Golgi-complex. The differentiating acrosome in the late spermatid moves to the anterior tip of the head. In the completed acrosome, a flocculent substance accumulates in the conspicuously expanded invaginated pocket of the acrosomal vesicle and two kinds of material of different electron density fill the inside of the acrosomal vesicle. The spermatozoa remain connected to the central mass at the lateral side of the head until they become fully mature and are packed into the nephridia before spawning.     

Left-handed Helical Polynucleotides with D-Sugar Phosphodiester Backbones

Naturally occurring polynucleotides have right-handed helical confrontations in the solid state¹ and in solution². Poly(dI-dC)poly(dI-dC) was found to form a left-handed helix in spite of the D-sugar backbone. Also, L-adenylyl-(3′–5′)-L-adenosine synthesized by Tazawa et al⁴. takes up the left-handed stacked conformation. We had synthesized a dinucleoside monophosphate, 8,2′-anhydro-8-mercapto-9-β-D-arabinofuranosyladenine phosphoryl-(3′–5′)-8,2′-anhydro-8-mercapto-9-β-D-arabinofuranosyladenine (A^spA^s) (molecular structure Ia; see also ref. 5) and this compound has a left-handed stacked conformation. The two bases in Ia, having the D-sugar backbone, stacked along the left-handed helical axis; these bases are fixed at ?_CN = ?108° (syn-anti region) by the anhydro linkages.     

SPERMIOGENESIS IN BARNACLES WITH SPECIAL REFERENCE TO ORGANIZATION OF THE ACCESSORY BODY*

Ultrastructural changes during spermiogenesis in the barnacles, Balanus amphitrite albicostatus, Balanus tintinnabulum rosa, Balanus trigonus and Tetraclita squamosa japonica, and organization of the sperm with special reference to the accessory body were studied. The Golgi complex organizes both the acrosome and the accessory body at different stages during spermiogenesis; the former is formed at the mid-spermatid stage and the latter is formed at the late spermatid stage. The arrangement of the components in the mature filiform sperm is quite unique, with the acrosome, the basal body just behind the acrosome, the axial filament parallel to a long nucleus, and a slender long mitochondrion behind the nucleus. The sperm in the anterior and posterior half of the ejaculatory duct differ from each other in form in that the sperm in the anterior duct are not equipped with the accessory body and the sperm in the posterior duct are. The accessory body can be artificially broken down by some treatments (1 M urea, alkaline sea water: pH 9.0-9.7, low ionic concentration of sea water). The loss of the accessory body from the sperm is assumed to be related to the ferti-lizability of the sperm.     

Citrus limonoid by-products as insect control agents

Limonoids are a group of chemically related bitter tetranortriterpene derivatives found predominantly in Rutaceae and Meliaceae plants (Ourison et al., 1964). Interest in the Rutaceae limonoids has centered around limonoid removal from consumable citrus products. For example, bitterness in citrus juices (as well as in other citrus products) due to limonoids has become an increasingly serious economic problem (Wilson & Crutchfield, 1968; Sinclair, 1972). Interest in the Meliaceae limonoids, on the other hand, has centered on their efficacy as pest control and/or antitumor agents (Kubo & Klocke, 1981, 1982; Nakanishi, 1977, 1980). For example, azadirachtin, isolated from several Meliaceae trees, has proven to be a potent natural product against a myriad of insect and nematode pests (Warthen, 1979). In fact, we have isolated azadirachtin from the fresh fruit of Azadirachta indica as a potent insect ecdysis inhibitor against four agricultural pest insects with artificial diet feeding assay (Kubo & Klocke, in litt).