Tsuneo Moriya

Arylsulfatase of sea urchin sperm: 2. Arylsulfatase as a lysin of sea urchins☆

Abstract An arylsulfatase is defined as a lysin of sea urchin sperm from the following evidences. (1) The activity is detected in the sperm of all the sea urchins investigated, and the activity is partially liberated from the cells after the acrosome reaction ( Moriya and Hoshi, 1979 ). (2) Fertilization is completely inhibited in the presence of 40 m Mp -nitrophenyl sulfate, which is an artificial substrate of arylsulfatase, but is not inhibited by p -nitrophenyl phosphate at the same concentration. (3) The inhibitory effect of p -nitrophenyl sulfate on fertilization is remarkably diminished by pretreatment of eggs with arylsulfatase before insemination. (4) Sperm arylsulfatase as well as limpet arylsulfatase appear to digest the vitelline coat and jelly coat.

The effect of temperature on the action of thyroid hormone and prolactin in larvae of the salamander Hynobius retardatus

To elucidate the environmental factors and endocrine mechanisms which are responsible for inducing neoteny in the salamander Hynobius retardatus, the effect of temperature on the growth and metamorphosis of this amphibian, as well as the actions of thyroid hormone and prolactin at low temperature, were studied. (1) The metamorphosis of larvae cultivated at 10 degrees was significantly delayed compared with that of larvae cultivated at 22 degrees, but the metamorphosis was eventually completed. At 4 degrees, metamorphosis never occurred, even after 2 years. (2) Exogenously administered thyroid hormone accelerated metamorphosis at 10 degrees or 22 degrees, but was ineffective in larvae kept at 4 degrees, whether administered by injection or immersion. (3) If a higher concentration of thyroid hormone was given by a single injection to larvae cultured at 4 degrees, an appreciable acceleration of metamorphosis was observed after transferring the larvae to 22 degrees. (4) Unlike thyroid hormone, prolactin promoted growth at 4 degrees.

Cytological changes induced by low temperature in the thyroid glands of larvae of the salamander Hynobius retardatus

In order to study the environmental conditions and the endocrine mechanism which induce neotenous characteristics, the fine structure of the thyroid glands of larvae of the salamander Hynobius retardatus were examined. The thyroid glands of larvae exposed to a low temperature (4 degrees) were compared with those of larvae exposed to a higher temperature (20 degrees). At 4 degrees, the follicular lumen was large and its contents of low electron density; the epithelial cells were flat or cuboidal. In contrast, the 20 degrees larvae showed a small dense lumen and tall cylindrical epithelial cells, which may indicate a higher level of activity. No apical vesicles were found in the epithelial cells of the 4 degrees larvae, although they were present in 20 degrees larvae. On the other hand, in 4 degrees larvae the chromatin in the nuclei was scattered, while in 20 degrees larvae it was condensed. In addition, large dense granules occupied 2.4% of the epithelial cytoplasm in 4 degrees larvae and as much as 7.3% in 20 degrees larvae. The structural features observed in larvae exposed to the cold resembled those reported for thyroid glands made inactive by a lack of thyrotropin.

Characterization and partial purification of arylsulfatase from the seminal plasma of the sea urchin, Strongylocentrotus intermedius

Abstract Arylsulfatase from seminal plasma of the sea urchin, Strongylocentrotus intermedius, was characterized with a crude enzyme preparation using p-nitrophenyl sulfate as the substrate. The enzyme which exists in soluble form, requires Ca2+ for the expression of full activity and calcium may be replaced by Ba2+, but only partially by Mg2+ and Sr2+. EDTA, heavy metals (Zn2+, Cu2+, Fe3+), and divalent anions including sulfate reduce the enzyme activity, however the enzyme is not so sensitive to sulfhydryl reagents. The inhibition with divalent anions is of a competitive nature. The optimum pH is 6.8 in 10 m m Tris-maleate buffer, but it shifts to 8.0 if the concentration of the buffer is increased to 100 m m . The enzyme hydrolyzes ascorbate-2-sulfate in addition to p-nitrophenyl sulfate, with Km values of 0.53 and 0.50 m m for p-nitrophenyl sulfate and ascorbate-2-sulfate, respectively. Cerebroside sulfate, seminolipid, cholesteryl sulfate, and proteochondroitin sulfate are not hydrolyzed appreciably by the enzyme. Although the enzyme is fairly stable at −20 °C, it is rather labile at 0 °C. The enzyme was partially purified by ammonium sulfate precipitation and successive chromatographies on Ultrogel AcA 34 and DEAE columns. At the final step, the enzyme was purified 47-fold, however, some heterogeneity on electrophoresis was evident.

Arylsulfatase of sea urchin sperm—Distribution of arylsulfatase in the gonads and gametes of echinoderms

1. Fairly high activities of arylsulfatase are found in the sperm and mature testes of all the sea urchins studied; Strongylocentrotus intermedius, Strongylocentrotus nudus, Hemicentrotus pulcherrimus and Anthocidaris crassispina, whereas the activities in the ovaries and eggs of these animals are low. 2. Neither the sand dollar, Clypeaster japonicus nor the starfishes, Asterias amurensis and Asterina pectinifera prove to have considerable activities of the enzyme in their gonads and gametes. 3. Most of the activity of arylsulfatase in the sperm of S. intermedius is found in the seminal plasma, but the significant activity is bound to the spermatozoa. 4. Part, if not all, of the spermatozoa-borne arylsulfatase is suggested to exist on the surface of spermatozoa or in the acrosome or both. 5. The ubiquitous distribution of sperm arylsulfatase in sea urchins on the contrary to its absence in starfish or sand dollar is discussed in connection with the penetration of sperm through egg investments.