Species Specificity of the Insect Prothoracicotropic Hormone (PITH): the Presence of Bombyx-and Samia-Specific PTTHs in the Brain of Bombyx mori

Crude extracts of Bombyx mori brains can provoke adult development when injected into brain-removed dormant pupae of Bombyx mori and Samia Cynthia ricini. From this fact the prothoracicotropic hormone (PTTH) of Bombyx has long been thought to be species-nonspecifically active on Samia. Chemical fractionation of Bombyx brain or head extracts by fractional precipitation with acetone, Sephadex G-50 gel-filtration, and DEAE-Sepharose CL-6B chromatography, however, separated the fractions which activated Bombyx brainless pupae from those which activated Samia. Those results reveal the existence of two species-specific PTTHs.     

Internalization of Embryonal Carcinoma Cells when Aggregated with Normal Mouse Embryos

In the present study, we examined in detail the process of forming chimeric blastocysts between B242g embryonal carcinoma (EC) cells and normal mouse embryos. Electron microscopic observations of the developing aggregates revealed that the embryonic cells spread over the surface of the EC cells, resulting in the internalization of EC cells in the aggregates. When a single blastomere of an 8-cell embryo was aggregated with EC cells, the blastomere spread over and engulfed the EC cells. These results strongly suggest that EC cells are segregated and become situated in the inside position as the development of an aggregate proceeds, and then they are incorporated into the ICM of a blastocyst.     

HORMONAL REGULATION ON THE INDUCTION OF {alpha}-AMYLASE ISOZYMES IN THE EMBRYO-LESS ENDOSPERM OF BARLEY

The -amylase induced by helminthosporol and gibberellic acidin the embryo-less endosperm of barley was separated into thethree fractions, 1, 2 and 3, by DEAE-cellulose column chromatography.A maximum amount of the 2. was induced by gibberellic acid andthat of the as by helminthosporol. After rechromatography, the2 induced by gibberellic acid and the as induced by helminthosporolshowed their respective single bands in an electrophoresis agargel zymogram. On the other hand, the ai induced by helminthosporoland gibberellic acid showed three bands. Dihydrohelminthosporic acid, a derivative of helminthosporol,induced the same isozymes as helminthosporol did. (Received May 8, 1967; )     

Subunits of Xanthine Dehydrogenase and Their Differential Appearance in Chick Tissues During Development

Xanthine dehydrogenase (XDH) from adult chick liver comprises two polypeptide chains of different size in a molar ratio of 1: 1. The molecular weights of these subunits were estimated to be 155K (α) and 135K (β) daltons (1). However, XDH isolated from the liver of newly hatched chick was not found to represent the equimolar ratio of these two subunits; that is, the amount of subunit β was lower than that of subunit α. While examamining electrophoretically the change in the amounts of these subunits in the liver, the subunit α was found to appear earlier in the embryonic stage, but β only after hatching. In the kidney, however, both subunits were detected before hatching, being consistent with the fact that XDH exists before hatching in the kidney. The two subunits also appeared differentially in the kidney; i.e., subunit α appeared earlier than subunit β. In either tissue, the rate of increase in XDH activity corresponded to that of subunit β. Thus, the synthesis of two subunits of XDH are separately regulated at least until just after hatching.     

Flipper Bands Modify the Short-Term Diving Behavior of Little Penguins

ABSTRACT Flipper banding has long been the primary method to identify individual penguins, despite studies indicating that it may be detrimental to breeding success and survival. Our objectives were to measure the effects that flipper bands may have on diving performance of little penguins to determine whether the bands may be detrimental. We studied short- and long-term direct effects of flipper banding on diving behavior of free-ranging little penguins (Eudyptula minor) by comparing diving behavior before and after banding and by comparing diving performance of unbanded birds to those that had carried flipper bands for several years, respectively. Recently banded birds displayed increases in multiple variables following banding. Long-term banded penguins did not exhibit differences to their unbanded counterparts in most variables examined. Our findings are useful to those considering or reviewing the use of bands in penguin study and management.