天蚕卵黄原蛋白cDNA的克隆及序列分析

天蚕卵黄原蛋白cDNA的全碱基序列由5 720个碱基构成,一个开读框有5 334个碱基序列,编码了包括由15个氨基酸组成的信号肽在内的共1 778个氨基酸的蛋白质前体。天蚕和柞蚕卵黄原蛋白的同源性非常高,氨基酸序列达到92.6%,碱基序列达到94%。天蚕、柞蚕和家蚕的卵黄原蛋白的糖链附加位点(N-linkedg-lycosylationsite):柞蚕有4个,家蚕有5个,天蚕和家蚕相同保存着5个。在N-末端区域,天蚕和家蚕有多聚丝氨酸区域和可被胰蛋白酶识别的RSRR部位;柞蚕虽然也具有多聚丝氨酸区域,但没有可被胰蛋白酶识别的RSRR部位。在C-末端区域里,大多数昆虫从G ICG功能部位至C-末端结尾具有7个~10个半胱氨酸(Cys)。鳞翅目的4种昆虫柞蚕、天蚕、家蚕和舞毒蛾(A.pernyi,A.yam am ai,B.m ori,L.dispar)都是7个半胱氨酸。     

Accumulation of Trehalose as a Compatible Solute under Osmotic Stress in Euglena gracilis Z

ABSTRACT. The photosynthetic protozoon Euglena gracilis, accumulated a large amount of trehalose in the cells under salt or osmotic stresses. Radioactivity of [14C] paramylon, a β-1,3-polyglucan which was stored in the cells of E. gracilis. was degraded rapidly and this radioactivity was almost stoichiometrically incorporated into trehalose. The interconversion of trehalose from paramylon by salt or osmotic stresses was dependent on the concentrations or osmotic pressures, suggesting that E. gracilis accumulate trehalose as an osmoprotectant. After the removal of salt or osmotic stresses, trehalose was gradually degraded, however, it was not converted into paramylon.     

Calcium Deposition in Idioblasts of Mulberry Leaves

Large, rounded idioblasts were observed in adaxial leaves ofmulberry plants; they were clearly distinguishable from epidermal,trichome and parenchyma cells. The size and density of idioblastsvaried according to leaf age. Cytological features of idioblastswere as follows: the outermost region (‘cap’) ofidioblasts was situated on the adaxial surface as a dome-likeprotrusion; a cylindrical protuberance extended from the capregion to the inner part of the idioblast; in idioblasts frommature leaves a crystal mass was suspended from the lower tipof the cylindrical protuberance. Elemental analysis of idioblastsdemonstrated that silicon (Si) was localized in both the capregion and the cylindrical protuberance but calcium (Ca) waspresent in the large crystal, indicating site-specific cellularlocalization of Ca and Si within an idioblast. Histochemicalassays showed that a distinct Ca crystal filled the vacuolesof idioblasts in mature leaves, while immature leaves had manyidioblasts without Ca deposition. The increase in the Ca contentof leaves was directly proportional to the increase in leafage and appeared to be closely related to the Ca sink capacityof the developing idioblast vacuoles. The maximum sink capacitywas quantified to be approximately 40 ng per idioblast whenmulberry plants were grown hydroponically with excess Ca.Copyright1999 Annals of Botany Company Morus alba, idioblast, Ca deposition, Ca sink capacity, silicon, X-ray microanalysis, histochemistry, scanning electron microscopy.     

蓖麻蚕卵黄原蛋白cDNA的克隆及序列分析

本文论述了蓖麻蚕卵黄原蛋白cDNA迅速克隆化的方法,SDS－PAGE鉴定的蓖麻蚕卵黄原蛋白由大小二个亚基构成,求出的分子量大亚基为180kDa,小亚基为45kDa,从解析的蓖麻蚕卵黄原蛋白氨基酸序列推算的分子量大亚基为161．06kDa,小亚基为40．53kDa,如果考虑到翻译后的修饰,这与SDS－PAGE求出的分子量是吻合的。蓖麻蚕卵黄原蛋白cDNA是由5788pb构成,一个ORF为5337个碱基,编码了1779个氨基酸。在信号肽的15个氨基酸残基中,有12个是硫水性氨基酸残基。这与其他昆虫卵黄原蛋白信号肽区域的硫水性分析是一致的。蓖麻蚕卵黄原蛋白N-linked glycosylation site的分布与家蚕、柞蚕和天蚕不同,3处N-linked glycosylation site存在于大亚基里,2处地多聚丝氨酸区域上流的小亚基里。另外,我们发现在所解析的柞蚕、天蚕的蓖麻蚕卵黄原蛋白氨基酸序列的C－末端区域里DGQR、GICG功能部位及其后的6个半胱氨酸都完好地保存。     

The Argentine ant, Linepithema humile, in Japan: Assessment of impact on species diversity of ant communities in urban environments

The Argentine ant Linepithema humile (Mayr) invaded the Hiroshima Prefecture in south‐west Japan some time before 1990. In this report, we describe the distribution of this exotic ant species and assess its impact on indigenous ant communities in urban areas. L. humile is now widely distributed mainly in urban areas and surrounding secondary vegetation of the cities Hatsukaichi and Hiroshima. The impact assessment suggested that L. humile reduced species diversity of local, indigenous ant communities. There was differential sensitivity of indigenous ant species to the invasion of L. humile. Some ant species disappeared in parks infested with L. humile; for example, Pheidole noda, Pheidole indica and Lasius japonicus. L. humile seemed to be superior to these ant species in certain traits and habits, such as mobility, recruitment ability, aggressiveness and omnivory. In contrast, Paratrechina sakurae and Camponotus vitiosus were less affected by L. humile infestation. The mechanisms allowing such coexistence seemed to be small body size (P. sakurae) and arboreal nesting habits (C. vitiosus).     

GENETIC ANALYSIS OF DEVELOPMENTAL MECHANISMS IN HYDRA I. SEXUAL REPRODUCTION OF HYDRA MAGNIPAPILLATA AND ISOLATION OF MUTANTS

Hydra magnipapillata strains collected from various localities in Japan were induced to reproduce sexually.
From the survival data of the progeny, it was calculated that H. magnipapillata contained an average of between 3.5 and 4.0 lethal equivalent units of recessive deleterious genes per gamate (between 7.0 and 8.0 per animal).
Various types of developmental mutants were found among the offspring of crosses made between strains isolated from the same ponds. The mutant types isolated included mini strains, maxi strains, multi-headed strains, nematocyst-deficient strains, regeneration-deficient strains and male sterile strains. The characters of these strains were stably transmissible to the successive progeny produced by budding. These strains therefore were propagated by budding and maintained as clonal lines to be used later for developmental studies.     

GENETIC ANALYSIS OF DEVELOPMENTAL MECHANISMS IN HYDRA VII. STATISTICAL ANALYSES OF DEVELOPMENTAL-MORPHOLOGICAL CHARACTERS AND CELLULAR COMPOSITIONS

Various strains belonging to Hydra magnipapillata are examined for their developmental-morphological characters and relative abundance of the six basic types of cells, and the results are statistically analysed.
Significant correlations are found between various (including seeming unrelated) characters. For example, budding rate, bud developmental rate and polyp size, which in theory can be all regulated by independent mechanisms, show strong correlations with each other. This suggests that the underlying mechanisms regulating these characters must be closely related to each other.
Similar significant coerelations are also found between the relative abundance of various cell types, but not between the developmental-morphological characters and the cellular composition. The significance of these findings are discussed.     

Genetic Analysis of Developmental Mechanisms in Hydra. XV. Nematocyte Differentiation in Strains with Altered Developmental Gradients*

Nematocyte differentiation from the interstitial stem cells in hydra occurs non-uniformly along the body column. The relative ratios of the 4 nematocyte types produced vary gradually from head to foot along the body axis (Bode and Smith, 1977). To find out whether this regional variation in nematocyte differentiation along the body column is related to the gradients of the head-activation and head-inhibition potentials, nematocyte differentiation patterns were examined in strains which have significantly different developmental gradients along their body columns. Five strains of hydra, including a wild-type, two mutant strains and two chimeric (mutnt/wild-type) strains, were investigated. It was found that the regional variations in the nematocyte differentiation were similar in all the strains examined, and that no significant differences of the variation existed that could be attributed to the differences of the developmental gradients in these strains. This suggests that nematocyte differentiation is strongly affected by the axial position along the body column, but that the gradients of the morphogenetic potentials involved in head formation are not involved in this effect. Instead, some other parameter(s) of axial position not directly associated with these gradients must be responsible for the positional effect on nematocyte differentiation.