Hormonal Control of Gametogenesis in the Terrestrial Snail, Euhadra peliomphala

Effects of the cerebral ganglion (brain) and the optic gland on oogenesis and spermatogenesis were studied in the terrestrial snail, Euhadra peliomphula. Removal of the optic tentacles inhibited both oogenesis and spermatogenesis. These effects were abolished by the injection of the optic tentacle extract. In the tissue of the optic tentacle, only the optic gland showed the recovery action. Furthermore, in vitro the optic gland extract stimulated spermatogenesis but had no effect on oogenesis. On the contrary, the brain extract promoted oogenesis not only in vitro and but also in viva The hermaphroditic gland extract reduced the nuclear volume of the optic gland cells, but the brain extract did not. In addition, among sex steroid hormones secreted from the hermaphroditic gland, only testosterone also reduced the nuclear volume of optic gland cells. On the basis of these results, hormonal mechanisms of gametogenesis in Euhadra peliomphala are discussed.     

Developmental Fates of Blastomeres of Eight-Cell-Stage Xenopus laevis Embryos

The developmental fates of animal, vegetal, dorsal, and ventral egg regions of Xenopus laevis embryos were examined. For this purpose, a tracer enzyme (horseradish peroxidase) was injected bilaterally into pairs of eight-cell-stage blastomeres and the clonal organization of marked cells in the early tail-bud embryos was examined. The epidermis over most of the body originated from animal-ventral micromeres, but that in the head originated from animal-dorsal blastomeres and that in the area surrounding the anus originated from vegetal-ventral blastomeres. The neural tube originated from animal-dorsal, vegetal-dorsal, and animal-ventral blastomeres. These results were consistent with those of previous studies. But in contrast to previous findings, results showed that the entire notochord is derived from animal-dorsal micromeres and that the somites originate from all four bilateral pairs of blastomeres in the eight-cell stage. These results are discussed in relation to the current maps of prospective fates based on results of vital-dye staining. Morphogenetic movements are also discussed on the basis of the clonal organization demonstrated in the present study.     

Purification of Acetylcholinesterase from Sea Urchin (Hemicentrotus pulcherrimus) Embryos by Affinity Chromatography

Only one form of acetylcholinesterase (AchE) was detected in Hemicentrotus pulcherrimus embryos. In H. pulcherrimus embryos as well as in the other sea urchin embryos, AchE activity begins to increase rapidly after gastrula stage.
Purification of AchE from plutei has been carried out by the procedure including affinity chromatography. Purified AchE had the activity 14,600 times higher than that of homogenate, and the final yield of AchE was 8%. The enzyme seems to be electrophoretically homogeneous, and has a molecular weight of 3 × 10⁵ as determined by Sepharose CL–6B column chromatography.     

β-Lactoglobulin Suppresses Melanogenesis in Cultured Human Melanocytes

The effects of whey proteins from bovine milk on melanogenesis in cultured human melanocytes were examined. Among the major protein components of milk whey including β-lactoglobulin (BLG), α-lactalbumin, serum albumin, and IgG, only BLG exhibited the depigmenting effect at a concentration of 1 mg/ml. Also, BLG suppressed the activity of tyrosinase in these cells. Retinol, to which BLG is known to bind, slightly increased the pigmentation of the cells at concentrations in the range of 1–100 nM, and retinoic acid, a metabolite of retinol, exhibited a strong pigmentation-promoting effect within the same concentration range. Treatment of the cells with 1 mg/ml BLG completely abrogated the pigmentation induced by these A vitamins. These results demonstrate a novel biological activity of BLG and suggest that this activity is dependent on its ability to bind retinol.     

PROTEINS OF WHEAT EMBRYOS IN THE PERIOD OF VERNALIZATION

1. Soluble proteins prepared from non-vernalized and vernalizedwheat embryos were investigated by means of column chromatographyand disc electrophoresis. As vernalization proceeded, new proteinswere detectable as the fastest moving electrophoretic bandsor as the new peaks which were eluted with 0.025 M and 0.05M phosphate buffer (pH 7.0) from DEAE-cellulose. Plumule wasfound to be the part of embryo in which these proteins appear.After vernalization, protein pattern of winter wheat embryowas very similar to that of spring wheat embryo.
2. Histoneswere prepared from non-vernalized and vernalized wheatembryosand their chromatographic patterns were investigated.Winterwheat embryo showed more complicated pattern than didspringwheat embryo. Upon vernalization, histone pattern ofwinterwheat embryo became less complicated and similar to thatofspring wheat embryo.

(Received October 4, 1966; )     

Spiral Motion of Paramecium caudatum in a Small Capillary Glass Tube

SYNOPSIS. The behavior of Paramecium caudatum in small capillary glass tubes was investigated under various ionic conditions and at the various tube diameters. Along the inner walls of the tubes ciliates undergo regular spiral motion, which is completely different from natural spirallings or random walk-like movements observed usually in large vessels. The curvature calculated from the tracks of spiral motions was independent of the inner diameters of capillary tubes, but depend specifically on ionic conditions.
A plausible law governing such regular spiral motions of Paramecium caudatum is proposed. A definite part of the anterior end of a ciliate seems to contact the curved surface of the inner wall of a capillary tube during the motion so that the organism receives a constant tactile stimulus, and the direction of motive force keeps a certain angle against the surface.     

FLOWER-PROMOTING EFFECT OF GIBBERELLIN IN WINTER WHEAT AND BARLEY

1. Vernalized and unvernalized seeds of barley were sown in greenhouseunder short day or long day condition. At the second leaf stage,a half of the plants in each plot was sprayed with gibberellin.Plants grown from vernalized seeds headed at about the sametime under long day condition, whether they were treated withgibberellin or not. Under short day condition, however, gibberellinpromoted heading. With plants grown from the unvernalized seeds,gibberellin promoted heading under long day condition whereasit delayed heading under short day condition. Thus the substitutionof gibberellin for long day effect and for vernalization effectwas shown.
2. Immature embryos growing on developing ear of wheatand barleywere vernalized with low temperature combined withor withoutgibberellin application. Plants grown from the seedstreatedat their early ripening stage with low temperature combinedwith gibberellin gave earlier heading, associated with the decreasedleaf number, than the plants from seeds treated with low temperaturealone. This effect of gibberellin lasted for a half-year ofseed storage.
3. Gibberellin was applied to germinating seedsunder vernalizationtreatment. Gibberellin promoted floweringin varieties whichpossess high requirement for chilling vernalization,when thechilling was insufficient to satisfy the high requirement.However,the effect of gibberellin was obscure with varietiespossessingrelatively low requirement for vernalization.

(Received September 15, 1964; )     

ROLE OF SULFUR IN THE CELL DIVISION OF CHLORELLA, WITH SPECIAL REFERENCE TO THE SULFUR COMPOUNDS APPEARING DURING THE PROCESS OF CELL DIVISION II.

1. Chlorella cells, which had been grown synchronously undersulfur-deficient conditions and thus rendered unable to performcell division, were made capable of nuclear and cellular divisionby being supplied with ³⁵S-labeled sulfate and nitrate underphotosynthesizing conditions, and the fate of sulfur duringthese recovery processes was followed. 2. When the S-starved cells were provided with sulfate aloneunder photosynthesizing conditions, cells grew appreciably inmass performing nuclear division but remaining incapable ofcellular division. During these processes most of the ³⁵S wasfound to be incorporated into the protein fraction of algalcells. 3. When the cells which had been stalemated at the above-mentionedstage were supplied with nitrate, they grew further in massand eventually performed cellular division. During this periodthe ³⁵S was found to be distributed not only in the proteinfraction, but also in an appreciable amount in the cold andhot acid-soluble fractions. 4. By paper-electrophoretic experiments it was found that thenature of the sulfur substances appearing in the hot acid-solublefraction changed strikingly during the process of cellular division.Zone electrophoresis and an anion-exchange chromatography ofthese substance isolated from the cells at the completion ofcellular division, disclosed that they were most probably deoxypentosepolynucleotides containing sulfur in some form yet unidentified. 5. It was demonstrated that there exist some antagonistic relationsbetween the protein synthesis and the formation of these sulfur-containingdeoxypentose polynucleotides, and that the former predominatesunder photosynthesizing conditions while the latter outweighsunder nonphotosynthesizing conditions. (Received August 9, 1960; )     

用生物素-中性抗生物素蛋白结合导致的位阻来控制连接生物素的缓激肽生物活性(英)

缓激肽是一含有9个氨基酸残基的多肽,其残基序列为Arg¹-Pro²-Pro³-Gly⁴-Phe⁵-Ser⁶-Pro⁷-Phe⁸-Arg⁹-OH,在激肽释放酶的作用下, 从其大的前体多肽——激肽原而形成的.许多发病机理,如发炎、疼痛、哮喘等都与缓激肽有关. 它能与PC12细胞表面的受体作用,引起细胞器内的钙离子释放,在共焦显微镜下,通过观察钙指示剂Fluo-3荧光增加来监测缓激肽的生物活性.在这项研究中,利用固相肽合成方法合成了连接生物素的缓激肽,Biotin-Arg¹-Pro²-Pro³-Gly⁴-Phe⁵-Ser⁶-Pro⁷-Phe⁸-Arg⁹-OH,通过对其生物活性的研究发现：a.它能保持象天然的缓激肽那样的生物活性;b.由于中性抗生物素蛋白与连接的生物素的结合引起的空间位阻阻碍它与细胞表面受体的相互作用,从而抑制了它的生物活性;c.在有自由的生物素存在的条件下,自由生物素与连接生物素与中性抗生物素蛋白的竞争结合,能够使得与中性抗生物素蛋白结合的连接生物素的缓激肽从抗生物素蛋白上脱离,因而恢复其生物活性.因此,可利用生物素和抗生物素蛋白来控制连接生物素的缓激肽的生物活性.这对于研究生物体系中生物活性的结构相关性具有重要的意义.