Local Degeneration of Cilia and Nuclear Activation during Sexual Reproduction in Paramecium caudatum

The correlation between local degeneration of cilia and nuclear activation during chemically induced autogamy in Paramecium caudatum was studied by experimental interruption of autogamy. When the induction of autogamy was interrupted 60 min after the onset of chemical induction, nuclear activation did not occur and ciliary regeneration took place at the deciliated surface. On the contrary, when it was interrupted 3 hr after the onset of induction, nuclear activation was not stopped and no reciliation was observed. At this critical stage, the deciliated zone was seen to extend to the right wall of the gullet. These findings suggest that there is a transition point in activation processes. It is conceivable that in autogamous cells that have gone beyond this transition point all processes of nuclear activation proceed, and that the ability to regenerate cilia is lost by the end of autogamy, even if the stimulus for autogamy is removed.     

A Specific Response to Toxic Cadmium Levels in Red Kidney Bean Embryos

Cadmium salts are highly toxic to excised embryos of Phaseolus vulgaris cv. Red Kidney, inhibiting growth at concentrations in excess of 3 mg/L Inhibition is accompanied by specific toxic responses, namely inhibition of greening and induction of acute curvature in the embryonic axis. Comparisons among some 24 elements at 10 mg/l for cadmium-like effects showed silver to affect curvature, but not greening, while cobalt and nickel were the converse.     

Studies on rice seed protease V. Protease inhibitor in rice seed

Protease inhibitor in rice seed was investigated physiologicallyin connection with rice seed protease. In rice seed, the inhibitorwas localized in the embryo and its activity decreased on germination.The inhibitor was a protein-like substance which, was non-diffusiblethrough cellophane membrane, salted out on addition of ammoniumsulfate, was denatured on heating it at 100°C and adsorbedonto ion-exchange cellulose. During incubation at 70°C for30 min, inhibitor activity remained unchanged, while the proteaselost its activity within 10 min. The protease and the inhibitorof rice seed were separated from each other by chromatographyon a TEAE-cellulose column. The inhibitor reduced the activityof rice seed protease. ¹ This report was presented in part at the annual meeting ofthe Society of the Science of Soil and Manure of Japan at Tokyoon April 1, 1968. ² Present address: Faculty of Agriculture, Kagoshima University,Kagoshima, Japan. (Received June 8, 1971; )     

Ciliate Protozoa in the Rumen of Kenyan Zebu Cattle,Bos taurus indicus,with the Description of Four New Species1

ABSTRACT. The composition of the fauna of rumen ciliates in zebu cattle in Kenya was surveyed and 13 genera containing 51 species with 19 formae were identified. Four new species were recognized, then described as Diplodinium africanum n. sp., Diplodinium nanum n. sp., Eudiplodinium kenyensis n. sp., and Ostracodinium iwawoi n. sp. In addition, Buetschlia triciliata and Ostracodinium stokyi were found for the second and third times and described as Hsiungia triciliata n. comb. and Enoploplastron stokyi n. stat., with two formae, respectively. The species composition was similar to that of Indian zebu but several species were considered to originate from African native ruminants. In the percentage composition of genera, the numbers of Entodinium, which normally predominate in rumens in other areas, were very low.     

Involvement of a Bacterial Factor in Morphogenesis of Bacteriophage Capsid

A new bacterial factor has been found necessary for the activity of T4 gene 31, the only catalytic factor in the early stage of phage head formation, to process the assembly of head precursor proteins. In a mutant missing this factor, the precursors of phage head aggregate on the bacterial membrane.     

Scanning Electron Microscopy of the Adoral Ciliary Zone of Entodinium Stein (Ciliophora,Entodiniomorphida)1

The adoral ciliary zone of the rumen ciliates, Entodinium spp., was observed topographically in the SEM. The upper side of the anterior end of the body was indented by the vestibulum, which had cilia arranged on its right wall and ribs along the left wall. The adoral ciliary zone could be divided into at least two arrangements. The outer ciliary zone had many membranelle-like structures, which consisted of cilia arranged radially from the body axis. Each membranelle-like structure consisted of two rows of about eight cilia each lining up in a single file. It was, however, different from a typical membranelle, because its cilia were connected with the vestibular cilia and were arranged not spirally but on a plane. These cilia extended toward the outside because of the projecting cytoplasm from which they originated. In contrast, the cilia of the inner ciliary zone were aggregated to form relatively unsystematic bundles. Since the vestibular opening was slanted on the upper side of the body, the ciliary bundles were thick on the lower side and sparse on the upper side of the body. Neither outer nor inner ciliary zones completely surrounded the vestibular opening. The ciliature started from the left side of the vestibular opening, encircled the lower side of the body, and entered the vestibulum from its right side. The functions of these two types of ciliary arrangements are discussed.