DISTRIBUTION OF SURFACE CHARGE ON SPERMATOZOA OF THE STARFISH, ASTERINA PECTINIFERA

The distribution of the negative charge on the surface of acrosome-reacted and intact spermatozoa of the starfish, Asterina pectinifera , was studied with the charged colloidal iron hydroxide (CIH) labelling technique. All parts of its surface were shown to have an equal negative charge. Influenza virus brought about a type of sperm agglutination in which cells lay parallel to each other. The even distribution of anions on the sperm surface may be due to the existence of sialic acid all over the sperm surface.     

A “NORMAL” DEVELOPMENT OF DENUDED EGGS OF THE STARFISH,ASTERINA PECTINIFERA*

Experimental conditions that allow “normal” development of starfish eggs stripped of the fertilization membrane are reported in this paper. Four kinds of intercellular relation are distinguished during the pre-hatching stages of these eggs. Cells from 2- to 8-cell stages are hardly related to each other, while those from 16- to 128-cell stages are bound loosely together. After the 8th division (about 5.5 hr after insemination at 21°C) cells adhere closely and cooperate with each other to perform morphogenetic movement of “blastulation”. This relation is taken over by that of a true multicellular system at about 10 hr after insemination. Closely after this, the function of cilia carries the embryo away from the substratum.     

STARFISH DIVERSITY IN THE WENLOCK OF ENGLAND

Abstract: Although their record extends back to the Early Ordovician, the occurrence of fossil starfish (Echinodermata: Asteroidea) is dependent almost exclusively upon horizons of exceptional preservation. Thus, asteroids found in Silurian obrution deposits of the English Midlands and Welsh Borderlands are particularly significant to an understanding of the early diversity of the group. Six species are described here: Hudsonaster? carectum sp. nov. (Hudsonasteridae), from the lower part of the Lower Elton Formation; and, from the Much Wenlock Limestone Formation, the hudsonasterids Doliaster brachyactis gen. et sp. nov. and Siluraster? ketleyi (Spencer, 1916), the lepidasterids Lepidaster grayi Forbes, 1850 and Lepidactis wenlocki Spencer, 1918, and the palasterinid Palasterina orchilocalia sp. nov. Though few in number, they show a diverse range of body morphologies when compared with Ordovician taxa: L. wenlocki had long, slender rays when fully grown whereas D. brachyactis is the first asteroid with the short‐rayed body form of extant cushion stars. Most distinctive of all is L. grayi, the earliest multiradiate taxon known, all complete specimens of which have 13 rays. This morphological variety is interpreted as indicating that by the Early Silurian starfish were exploiting a wide range of feeding habits and ecological niches.     

THE GEOTROPIC RESPONSE IN ASTERINA

Upon a surface inclined at angle α Asterina gibbosa orients upward during negatively geotropic creeping until the average angle (θ) of the path is such that Δ sin θ/Δ sin α = const. This is true also in positively geotropic movement. The direction of orientation may be temporarily reversed by mechanical disturbance. The variation of θ is greater at low slopes. Tests with directed impressed pulls, due to an attached cork float, show that the pull upon the tube feet is of primary consequence for the determination of θ. When the component of gravitational pull in the direction of movement reaches a fraction of the total pull which is proportional to the gravitational vector parallel to the surface, the laterally acting component is ineffective. On this basis, it follows that Δ sin θ/Δ sin α = const.     

EFFECT OF LOCAL APPLICATION OF 1-METHYLADENINE ON THE SITE OF POLAR BODY FORMATION IN STARFISH OOCYTE*

Mechanism by which the site of polar body formation is determined in starfish oocytes was investigated in relation to the action of 1-methyladenine (1-MeAde). Local staining with Nile Blue of Asterina pectinifera oocytes revealed that there exists a prospective site of polar body formation (PSPBF) on the nearest surface to the position of germinal vesicle. The site of polar body formation was found to shift to some extent from PSPBF toward the area locally applied with 1-MeAde, suggesting that the actual site of polar body formation is not determined yet at the germinal vesicle stage. Oocytes whose germinal vesicles had been shifted by centrifugation from PSPBF to the opposite surface before the commencement of germinal vesicle breakdown (GVBD) (less than 15 min after 1-MeAde treatment), failed to form polar bodies, whereas oocytes centrifuged after commencement of GVBD (20 min after 1-MeAde treatment) did form polar bodies where their fading germinal vesicles had reached by centrifugation. In the oocytes which failed to form polar bodies by centrifugation, an aster was observed near PSPBF of each oocyte. When inseminated, every oocyte treated with 1-MeAde developed normally irrespectively of the mode of polar body formation including the site and the occurrence, and the animal pole of every larva was derived from PSPBF.     

DEVELOPMENT OF THE SEA-STAR, ASTERINA BATHERI GOTO

Using natural spawning and artificial fertilization, the entire process of development from eggs to juveniles was observed in the sea-star, Asterina batheri Goto.
The breeding season of this animal in Tsukumo Bay and Toyama Bay is estimated to be late summer. The spawned eggs are approximately 430 μm in diameter and float near the surface of sea water. They develop, through a wrinkled blastula stage by holoblastic. radial cleavage, into a pear-shaped brachiolaria bearing 3 blunt brachiolar arms. Metamorphosis takes place while the brachiolariae are swimming. Ten days after fertilization, metamorphosis is complete; the resulting juveniles are about 800 μm in diameter and colored pale brown with a green tint. They bear 2 pairs of tube-feet and a terminal tentacle in each arm.
Development of this species is thus of the direct type, and very similar in every respect to that of Asterina coronata japonica , which is closely related to the present species.     

骨唇黄河鱼耳石早期形态发育和轮纹特征研究

研究了骨唇黄河鱼仔稚鱼耳石在实验室养殖条件下的发育过程和生长特点,确证了轮纹沉积规律。结果表明,在14.0-17.8℃孵化条件下,微耳石和矢耳石在受精后96h 30min出现,星耳石在出膜后第16天出现。仔稚鱼生长过程中矢耳石形状变化较大,由出膜时的圆形发育到稳定时的箭矢状。微耳石由近圆形发育成贻贝形,其中心核位置随发育明显偏移。星耳石形状不规则,从出现时的心形发育成为星芒状。微耳石和矢耳石在前后轴方向上后区的生长快于前区（P0.05）;在背腹轴方向上,微耳石腹区的生长快于背区（P0.05）,矢耳石背区的生长快于腹区（P0.05）,两对耳石的前后区半径之和与全长均呈线性相关。微耳石和矢耳石的第1个轮纹均在出膜后第2天形成,新增的轮纹数（微耳石IL,矢耳石IS）与出膜后的天数（D）表现出显著的线性相关,方程分别为: IL=0.9911D-1.0008（R2=0.9971,n=220,P0.001）和IS=0.9925D-0.10873（R2=0.9919,n=161,P0.001）,方程的斜率与1均无显著差异（P0.05）,表明两对耳石轮纹沉积均呈日周期性,生长轮为日轮。研究结果丰富了骨唇黄河鱼的发育生物学资料,可为研究其自然种群早期生活史提供参考。       

中国星盾炱属分类研究Ⅱ．

本文报道了产于中国的星盾炱属Asterina L(?)v.23个种,其中2个新种和15个国内新记录种。新种是山芝麻星盾炱Asterina helicteris Y.S.Ouyang et Y.X.Hu和柄果木星盾炱Asterina mischocarpi Y.S.Ouyang et Y.X.Hu。标本保存于广东省微生物研究所(GDIM)。     

中国星盾炱属分类研究Ⅰ.

本文报道了产于中国的星盾炱属Asterina L(?)v.的15个种,其中2个新种和5个国内新记录种。新种是沉香星盾炱Asterina aquilariae Y.S.Ouyang et B.Song和藤黄生星盾炱Asterina garciniicola Y.S.Ouyang et B.Song.标本保存于广东省微生物研究所(GDIM)。     

MECHANICAL PROPERTIES OF THE CELL SURFACE IN STARFISH EGGS

The mechanical properties of the cell surface of the starfish egg at various stages of maturation have been investigated using the cell elastimeter. When constant negative pressure was applied to a part of the cell with a micropipette closely in contact with it, it bulged out, and the bulge rapidly increased at first and then gradually reached a steady value within one min. The relation between the deformation of the cell surface (i.e. degree of bulging) and applied negative pressure was almost linear in both oocytes at the germinal vesicle stage and mature eggs. The surface force and the elasticity value: i.e., the product of the elastic modulus of the surface membrane (layer) and its thickness, were determined from the relation between the deformation and the negative pressure. The elasticity value was about 5 times the surface force in both oocytes at the germinal vesicle stage and mature eggs. When maturation of the oocyte was induced by 1-methyladenine, the stiffness of the cell surface decreased shortly before the breakdown of the germinal vesicle. The stiffness transiently increased at the time of formation of the first and second polar-bodies.     

FORMATION OF THE FERTILIZATION MEMBRANE BY INSEMINATION OF IMMATURE STARFISH OOCYTES PRETREATED WITH CALCIUM-FREE SEAWATER

When immature oocytes of the starfish, Asterina pectinifera , were treated with calcium-free seawater for 1 hr and then inseminated in normal seawater, they formed several blisters, indicative of polyspermy, and raised fertilization membranes. These oocytes continued to have intact germinal vesicles. Electron microscopic study revealed that the egg surface remained virtually unchanged after the treatment with calcium-free seawater. Upon insemination, however, the cortical granules broke down and the fertilization membrane was formed. These immature oocytes with ferilization membranes underwent maturation (germinal vesicle breakdown) after treatment with 1-methyladenine.
The treatment with calcium-free seawater seems to bring about some physiological change on the surface of immature oocyte, which bestows some attributes of maturation but is insufficient to mature the oocytes completely.     

星盾炱属新种

报道了星盾炱属Asterina L(?)v.两个新种。它们是栲星盾炱Asterina castanopsts B Song et Y.S.Ouyang和绣球花星盾炱Asterina hydrangeae B.Song et Y.S Ouyang。模式标本保存在广东省微生物研究所真菌标本室(HMIGD)。     

ON REVERSAL OF GEOTROPISM IN ASTERINA

A certain level of strychninization induces in Asterina reversal of geotropism from the normally geonegative movement to a persistent downward creeping. The effect of an attached float producing upward pull is to induce upward creeping, under these conditions, whereas normally it leads to downward movement. This reversal cannot be regarded as due to a mere intensification of the sensory effect of tension. It must be understood as representing a true reversal of inhibition. The temporary reversal of geotropism following mechanical disturbances (in the absence of strychnine) is interpreted in the same way.     

SITE OF 1-METHYLADENINE RECEPTORS IN THE MATURATION OF STARFISH OOCYTES

Maturation of vitelline coat-free (VCF) oocytes of the starfish, Asterina pectinifera , was studied. When the oocytes, the vitelline coats of which were elevated by adding the ionophorc A-23187, were forced through two sheets of copper mesh, the vitelline coats were completely removed from the oocytes. Although some of the VCF oocytes underwent germinal vesicle breakdown following this mechanical treatment, most of them retained the normal germinal vesicles. These VCF immature oocytes underwent breakdown of germinal vesicles after addition of 1-methyladenine (1-MA). Dose-response curves of VCF oocytes to 1-MA were similar to those of normal oocytes. These results indicate that 1-MA reacts with the plasma membrane and that the presence of the vitelline coat is not prerequisite for inducing oocyte maturation.     

WRINKLED BLASTULA OF THE SEA-STAR,ASTERINA MINOR HAYASHI*

In naturally raised embryos of Asterina minor, the changes of internal structure during the wrinkled blastula stage were followed. Eight hours after spawning, blastomeres on the surface of the coeloblastula drop into the blastocoel and eventually form multiple invaginations of the blastodermal layer. Four and a half hours after the commencement of wrinkling, the blastocoel appears to be filled by the developed invaginations. The invaginations then decrease in number and complexity, and 11.5 hr thereafter the wrinkled blastula stage ends, although gastrulation takes place before the complete disappearance of the wrinkle-invaginations.     

粘虫幼虫血淋巴中的凝集素

粘虫Mythlmna separata Walker幼虫血淋巴中含有凝集某些脊椎动物红细胞的凝集素,凝集活性可被乳糖、岩藻糖或神经氨酸抑制.用CNBr-sepharose 4B 进行亲和层析从血淋巴中分离的凝集素成分比较复杂,聚丙烯酰胺凝胶电泳显示三条区带,SDS聚丙烯酰胺凝胶电泳出现6个亚基,亚基分子量分别为71000、65000、56000、35000、33000及31000道尔顿.     

THE INTRACELLULAR DISTRIBUTION AND HETEROGENEITY OF RIBONUCLEIC ACID IN STARFISH OOCYTES

A study has been made of the content and composition of RNA in cytoplasm, nucleoplasm, and nucleoli from growing oocytes of the starfish Asterias rubens. The determinations were carried out, using ultramicrochemical methods, on units isolated by microdissection from fixed sections. Macrochemical and interferometric control experiments show that RNA can be quantitatively evaluated in this way. The results show that the growing oocyte represents a system in which the relations between the quantities of nucleolar, nucleoplasmic, and cytoplasmic RNA undergo great changes. These changes are continuous for nucleolar and cytoplasmic RNA so that their amounts may be predicted from the size of the cell. Nucleoplasmic RNA, on the other hand, shows great variations among different cells, independent of cell size. Purine-pyrimidine analyses show that each cell component contains an RNA which differs significantly from that of the other two. Cytoplasmic and nucleolar RNA are closely related, the only difference being a slightly higher guanine/uracil quotient for the nucleolar RNA. They are both of the usual tissue RNA type, i.e., they show a preponderance of guanine and cytosine over adenine and uracil. Nucleoplasmic RNA deviates grossly from the RNA of the other two components. Here the concentrations of adenine and uracil are higher than those of guanine and cytosine, respectively. This RNA consequently shows some resemblance to the general type of animal DNA although the purine/pyrimidine ratio is far from unity. Our data favor a nucleolar origin for the stable part of the ribosomal RNA and a nucleoplasmic one for the unstable part (the messenger RNA).