Localization of Possible Calcium-Binding Sites in the Cilia of Paramecium caudatum

SYNOPSIS. Electron-dense deposits indicating possible Ca-binding sites were found at the ciliary base of Paramecium caudatum fixed in a glutaraldehyde solution containing 5 mM CaCl₂. The deposits appeared mainly at the inner surface of the ciliary membrane above the "ciliary necklace" region, although they could also occur in the space between the outer and the central microtubules. In some cases a ring of exactly 9 deposits was found in a ciliary cross section of a cilium.     

CHICK BRAIN CREATINE KINASE ONTOGENY BEFORE THE ADVENT OF CREATINE AND INSULIN

The ontogeny of brain creatine kinase (CK) was studied during chick embryo development. The cytosolic activity increased 270% in 10 h from the 2nd to the 3rd days of incubation; this was followed by a plateau phase throughout development and at the end of incubation there appeared to be another increase of cytosolic and mitochondrial CK activities. Therefore, early embryonic chick brain CK is another‘constitutive’enzyme like the early embryonic chick heart CK since creatine has not been enzymatically detected in the embryo until day 4 of incubation. Insulin does not appear to stimulate the early increase of brain CK activity since the hormone is not present in the embryo until day 5 of incubation. It is likely that CK increase is associated with neuronal multiplication at early stages and possibly to neuronal maturation before hatching.     

On artifacts appearing in the histochemical fixation of glycogen

1. Fixation artifacts associated with glycogen translocation are prevalent in tissues of parenchymatous type and scarce or non-existent in tissues of loose type. 2. Liver tissue treated with M/3 NaOH solution before fixation did not show an uneven distribution of glycogen. This was interpreted as indicating that the liver, a tissue of parenchymatous type, was changed, so to speak, into a loose type of tissue by alkali treatment. 3. The so called Alkohol-flucht of glycogen was produced in Yoshida's ascites tumor cells by a procedure which changed a loose type of tissue into a parenchymatous one, that is, by packing the tumor cells tightly. 4. The translocation of glycogen in cells appeared to occur when the fixatives penetrated the cells rapidly from a single direction, but failed to occur when the cells were attacked by the fixative from all directions. 5. In dried smears of Yoshida's ascites tumor cells and bone marrow cells, the glycogen particles are translocated to the peripheral regions of the cells, and coalesce there. The production of these artifacts is related in some way to the physicochemical properties of the protoplasm and plasma membrane of the cells.     

The possibility of photo-induced induction of nitrate reductase in rice seedlings

Nitrate reductase activity in rice seedlings showed daily fluctuations.Seedlings placed in the dark slowly lost activity and quicklyregained it when exposed to sunlight. Etiolated seedlings alsoshowed rapid increases in activity when transferred to sunlight.This increase in activity by sunlight was inhibited by bothchloramphenicol and ethionine. Ethionine inhibition was reversedby methionine. Purification of nitrate reductase was carriedout by ammonium sulfate fractionation and DEAE-cellulose columnchromatography. Nitrate reductase was purified about 40-foldfrom plants placed in the dark and in sunlight. Incorporationof mediionine-S-¹⁴CH₃ into the nitrate reductase fraction wasstudied. In sunlight, the specific radioactivity of the nitratereductase fraction from the DEAE-cellulose column increased2-fold as compared with that of the crude extracts. Specificradioactivity did not increase in the dark. ¹Present address: Asahi Kasei Chemicals Industry Co., Ltd.,Sameshima 2-1, Fuji, Shizuoka, Japan (Received December 3, 1968; )     

Chemosensory Response in Blepharisma. I. Accumulation of Cells in Products of Bacterial Metabolism

ABSTRACT. Blepharisma cells were attracted by a pellet of live bacteria (Enterobacter) which was separated from the Blepharisma suspension by a cellulose membrane (fractionation: M.W. 14,000). The cells, however, were not attracted by killed bacteria. Crude and heat-treated supernatants obtained from bacterial suspension also induced chemoaccumulation of cells. These results suggest that the cells of Blepharisma detect certain small molecules, produced by live bacteria, that can pass through the cellulose membrane and are stable to heat. From the live bacteria supernatant, several ninhydrin-positive substances were isolated by means of two-dimensional thin-layer chromatography. Several of the spots contained substances that attracted the cells, indicating that certain ninhydrin-positive components, such as peptides or free amino acids (probably products of bacterial metabolism), may serve as a signal for food.     

A kinetic analysis of cadmium accumulation in a Cd hyper‐accumulator fern,Athyrium yokoscense and tobacco plants

Cadmium (Cd) accumulations in a Cd hyper‐accumulator fern, Athyrium yokoscense (Ay), and tobacco, Nicotiana tabacum (Nt), were kinetically analysed using the positron‐emitting tracer imaging system under two medium conditions (basal and no‐nutrient). In Ay, maximumly 50% and 15% of the total Cd accumulated in the distal roots and the shoots under the basal condition, respectively. Interestingly, a portion of the Cd in the distal roots returned to the medium. In comparison with Ay, a little fewer Cd accumulations in the distal roots and clearly higher Cd migration to the shoots were observed in Nt under the basal condition (maximumly 40% and 70% of the total Cd, respectively). The no‐nutrient condition down‐regulated the Cd migration in both species, although the regulation was highly stricter in Ay than in Nt (almost no migration in Ay and around 20% migration in Nt). In addition, the present work enabled to estimate physical and physiological Cd accumulation capacities in the distal roots, and demonstrated condition‐dependent changes especially in Ay. These results clearly suggested occurrences of species‐/condition‐specific regulations in each observed parts. It is probable that integration of these properties govern the specific Cd tolerance/accumulation in Ay and Nt.