PERIODIC CHANGES IN THE CONTENT OF PROTEIN-BOUND SULFHYDRYL GROUPS AND TENSION AT THE SURFACE OF STARFISH OOCYTES IN CORRELATION WITH THE MEIOTIC DIVISION CYCLE*

The sulfhydryl content of protein and the tension at the surface were measured for starfish oocytes from the first meiotic division to the cleavage stage. A cyclic change in both the protein-SH and the tension at the surface was found to accompany the division cycle, including the first and second meiotic divisions. It is concluded that the unequal meiotic divisions share the same character with the equal divisions of cleavage, with respect to changes both in the protein-SH and the tension at the surface.     

Peroxidase isozymes and their indoleacetate oxidase activity in the Japanese morning glory, Pharbitis nil

Distributions of peroxidase isozymes in various organs of theJapanese morning glory (Pharbitis nil CHOISY) are described.Most peroxidase isozymes had indoleacetate oxidase activity. (Received December 29, 1969; )     

Induction of colony initiation by Japanese native bumble bees using cocoons of the exotic bumblebee Bombus terrestris

The colony initiation rates of Bombus hypocrita (a native Japanese bumblebee) and Bombus terrestris (a European species) foundresses were compared after 4 weeks of exposure to B. terrestris cocoons. The B. terrestris cocoons, when replaced weekly, were effective for inducing oviposition by foundresses of both species. There were no significant differences in the colony initiation rates of B. terrestris and B. hypocrita, either with the control treatment or with the cocoons. The cocoon method was also tested for five species and two subspecies of native Japanese bumblebees. The colony initiation rate was higher for foundresses of the subgenus Bombus s. str. than for foundresses of the subgenera Pyrobombus, Diversobombus, and Thoracobombus. When replaced weekly, the cocoons of B. terrestris are effective inducers of colony foundation in three Japanese native species, namely B. ignitus, B. hypocrita hypocrita, and B. h. sapporoensis.     

Interaction between Glucocorticoids and Epidermal Growth Factor In Vitro in the Growth of Palatal Mesenchymal Cells from the Human Embryo

Previous studies of ours have shown that palatal mesenchymal cells from the human embryo (HEPM cells) are responsive both to the glucocorticoid dexamethasone (DEX) and epidermal growth factor (EGF) through mechanisms associated with cytoplasmic and cell surface receptors, respectively. HEPM cell growth was inhibited by DEX and was stimulated by EGF. In the present study, the interactions between DEX and EGF were investigated. DEX (10^–6 M) enhanced EGF-stimulated HEPM cell growth as assessed by an increase in cell number and ornithine decarboxylase activity under serum-free cell culture conditions. DEX also enhanced the specific binding of ¹²⁵I-EGF to these cells, which was reflected in an increase in both the number and the affinity of EGF receptors. EGF (1 ng/ml), on the other hand, decreased the number of sites per cell which specifically bind ³H-DEX. EGF completely prevented the inhibition by DEX of HEPM cell growth. These results indicate that DEX and EGF interact with each other in the process(es) regulating HEPM cell growth. This interaction may be partially influenced by direct modulation of existing receptors for DEX and EGF present in the cells.     

熊蜂气管内寄生螨布赫纳蝗螨的生物学特性观察

对新疆与河北地区野生明亮熊蜂及小峰熊蜂蜂王内寄生螨布赫纳蝗螨Locustacarus buchneri的生物学特性进行了初步观察。结果表明： 该螨对两种熊蜂的寄生率分别为10.43%和8.3%,寄生部位为气管与气囊。室内饲养至30天的蜂王体内寄生螨量明显高于饲养至60天的蜂王。未被螨寄生的蜂王与被寄生者比较,前者体重显著高于后者,但二者间产卵始期、产卵率、食卵率和存活率差异不显著。     

PERIODIC CHANGE IN THE TENSION AT THE SURFACE OF ACTIVATED NON-NUCLEATE FRAGMENTS OF SEA-URCHIN EGGS

Unfertilized eggs of the sea urchin, Hemicentrotus pulcherrimus , were separated into two fragments by centrifugal force. The enucleate fragment (merogone) was subsequently activated by treating it with butyric acid and the tension at the surface was continuously measured by a compression method. The activated merogone was found to exhibit cyclic changes in tension, with a temporal pattern very similar to that of the changes accompanying the division cycle of normally fertilized eggs. This indicates quantitatively the presence in the cytoplasm of some periodic activity which can be triggered without nuclear control. Further, a periodic thickening of the intrahyaloplasmic space of the activated merogone, as noted by K ojima (14), was confirmed on the basis of extended observation.     

Effect of low concentration of hydrogen peroxide on indoleacetate oxidase zymogram in Pharbitis nil

Indoleacetate oxidase activity in Pharbitis nil, Japanese morningglory, was zymographically examined. Some isozymes appearedonly after treatment with a low concentration of hydrogen peroxide.This phenomenon was assumed to be due to the overlapping ofboth isozymes and natural inhibitor substances on the zymograms. ¹Present address: Biological Institute, Department of LiberalArts, Shizuoka University, Ooya 836, Shizuoka, Japan. (Received September 30, 1968; )