Biophysical studies on subcellular particles V. Effects of temperature on the ferricyanide-Hill reaction, the light-induced pH shift and the light scattering response of isolated spinach chloroplasts

Effects of temperature on the ferricyanide-Hill reaction, thelight-induced pH shift (JpH) and the light scattering response(4LS) of isolated spinach chloroplasts were studied at temperaturesranging from 5 to 60°C. Activities which produce JpH and JLS under actinic illuminationdecreased with a rise in the reaction temperature above 30°Cand disappeared at 50°C. The ferricyanide-Hill reactionat pH 6.0 was stimulated by raising the reaction temperaturefrom 5 to 35°C, was slowed at higher temperatures and wasinactivated at 50°C. 4LS activity at temperatures below20°C depended on the activity of electron transport. With a rise in temperature of a suspension of chloroplasts whichexhibited JLS under actinic illumination, the scattering intensitydecreased. The decrease in scattering intensity was limited,at most, to an extent equal to ALS. The behavior of JLS whichdiffered from that of basal scattering is discussed in connectionwith a mechanism of JLS formation other than the shrinkage-swellingcycle. When activities were measured at 25°C with chloroplastswarmed transiently (2 min) at various temperatures (25–60°C),the dependence of JLS on the wanning temperature was identicalwith that on the reaction temperature, while the activitiesof both ferricyanide reduction and JpH formation were higherthan those measured at the corresponding reaction temperature.This suggested that the mechanism for 4LS formation could beirreversibly altered by a warming treatment and that it wasless stable against heat than the mechanisms of ferricyanidephotoreduction and 4pH formation. That is, transiently warmedchloroplasts showed a similar behavior to alkane-treated chloroplasts.The similarity is discussed in relation to the activity changethrough the possible and common cause of disordering of theorganized structures of lipophilic components in the lamellarmembranes. (Received June 5, 1971; )     

Temperature-Sensitive Behavior of Paramecium caudatum

SYNOPSIS. The effect of temperature on the behavior of swimming cells of Paramecium caudatum has been investigated by photographic analyses of their tracks in uniform temperature, in temperature gradient, or in temperature changing with time. When the cells were placed in the temperature gradient, the frequency of discontinuous directional changes of cells swimming toward the optimal temperature, the temperature of the culture, was much lower than that of the cells swimming in the opposite direction. This difference in the frequency of directional changes explained the observed accumulation of the cells at - the optimal temperature. When the temperature was suddenly changed toward the optimum, a transient decrease of the frequency of directional changes was observed and when the temperature was changed in the reverse direction, a transient increase of the frequency was noted. This transient response to the temperature change was the origin of the dependence of the frequency of directional changes on the swimming direction in the temperature gradient. Finally, the relation between the magnitude of the transient response and the rate of the temperature change was derived.     

Host immunoglobulin G titre and antibody activity in haemolymph of the tick, Ornithodoros moubata

Immunoglobulin G (IgG) in tick haemolymph was analysed immunochemically and biochemically for its antigenicity, antibody activity and relative concentration in a soft tick, Ornithodoros moubata (Murray) sensu Walton 1962 (Acari: Argasidae). Ouchterlony immunodiffusion tests showed that haemolymph from a tick engorged on rabbit IgG (or human IgG) through an artificial membrane, reacted with anti-rabbit IgG (anti-human IgG) but not with anti-human IgG (anti-rabbit IgG). This indicates that haemolymph of the fed tick contains IgG with a similar antigen specificity to host blood IgG. IgG from tick haemolymph was demonstrated by enzyme immunoassay to have the same antibody activity as ingested IgG. The IgG concentration in tick haemolymph was measured by a quantitative single immunodiffusion test. Changes of IgG titre after a bloodmeal were correlated with IgG activity, which was low for 5 days after a bloodmeal and then suddenly increased. The IgG titre reached a maximum 7 days post-engorgement, and remained high for over 4 months during and after oviposition. 125I-labelled IgG was injected into the tick haemocoel to determine the persistence of IgG in the haemolymph. Recovery of labelled IgG was low at 1 and 3 days, and high at 5, 8 and 16 days after engorgement. The data suggest that IgG in haemolymph disappears quickly soon after engorgement possibly by degradation and/or absorption (adhesion to tissues).     

K-Casein Suppresses Melanogenesis in Cultured Pigment Cells

The effects of bovine milk proteins on melanogenesis in B16 cells were examined. Both whey protein isolate and casein exhibited depigmenting properties. Among the major protein components of milk—including β-lactoglobulin, α-lactalbumin, α-, β-, and k-casein—only K-casein exhibited the depigmenting effect. However, the carboxyl terminal peptide of K-casein, glycomacropeptide, did not show this activity. Also, K-casein promoted the proliferation of the cells and inhibited the activity of tyrosinase in the cells. These results indicate that K-casein acts as a melanogenesis-suppressing modulator.     

DEVELOPMENT OF THE SEA-STAR, ASTERINA BATHERI GOTO

Using natural spawning and artificial fertilization, the entire process of development from eggs to juveniles was observed in the sea-star, Asterina batheri Goto.
The breeding season of this animal in Tsukumo Bay and Toyama Bay is estimated to be late summer. The spawned eggs are approximately 430 μm in diameter and float near the surface of sea water. They develop, through a wrinkled blastula stage by holoblastic. radial cleavage, into a pear-shaped brachiolaria bearing 3 blunt brachiolar arms. Metamorphosis takes place while the brachiolariae are swimming. Ten days after fertilization, metamorphosis is complete; the resulting juveniles are about 800 μm in diameter and colored pale brown with a green tint. They bear 2 pairs of tube-feet and a terminal tentacle in each arm.
Development of this species is thus of the direct type, and very similar in every respect to that of Asterina coronata japonica , which is closely related to the present species.     

Early oogenesis in the ascidian Ciona savignyi

Summary

Morphology of the germinal epithelium and the early follicular oocyte in the ascidian Ciona savignyi as examined by electron microscopy. The oogenetic part of the germinal epithelium contains oocytes at two different stages and the dark and clear cells. The smaller oocyte contains synaptonemal complexes. The larger oocyte in the initial phase of growth has a conspicuous nucleolus, electron-dense materials and some mitochondria close to the nuclear envelope. The nucleus of the larger oocyte is round and has the smooth contour. The dark cell contains a relatively large nucleus and is sometimes connected to each other by an intercellular bridge. Therefore, the dark cell, which has been suggested to be the progenitor cell of two kinds of accessory cells, may be also the oogonium. The early follicular oocyte just after migration from the germinal epithelium retains most of cytological features similar to those of the larger oocyte. However, the nuclear contour of the early follicular oocyte is uneven. This difference in the nuclear contour probably indicates that such a follicular oocyte is in the second phase of growth.     

Influence of different substrates on the evolution of morphology and life‐history traits of azooxanthellate solitary corals (Scleractinia: Flabellidae)

Sessile organisms are influenced considerably by their substrate conditions, and their adaptive strategies are key to understanding their morphologic evolution and traits of life history. The family Flabellidae (Cnidaria: Scleractinia) is composed of the representative azooxanthellate solitary corals that live on both soft and hard substrates using various adaptive strategies. We reconstructed the phylogenetic tree and ancestral character states of this family from the mitochondrial 16S and nuclear 28S ribosomal DNA sequences of ten flabellids aiming to infer the evolution of their adaptive strategies. The Javania lineage branched off first and adapted to hard substrates by using a tectura‐reinforced base. The extant free‐living flabellids, including Flabellum and Truncatoflabellum, invaded soft substrates and acquired the flabellate corallum morphology of their common ancestor, followed by a remarkable radiation with the exploitation of adaptive strategies, such as external soft tissue [e.g. Flabellum (Ulocyathus)], thecal edge spine, and transverse division (e.g. Placotrochus and Truncatoflabellum). Subsequently, the free‐living ancestors of two genera (Rhizotrochus and Monomyces) invaded hard substrates independently by exploiting distinct attachment apparatuses such as tube‐like and massive rootlets, respectively. In conclusion, flabellids developed various morphology and life‐history traits according to the differences in substrate conditions during the course of their evolution. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 184–192.     

Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula

Sentoku, A. & Ezaki, Y. 2011: Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula. Lethaia, Vol. 45, pp. 62–70. Scleractinia display a variety of growth forms, whether zooxanthellate or azooxanthellate, as the consequence of the combined effects of both intrinsic and extrinsic factors. New modules arise in colonial corals through asexual reproduction, including budding and division. The azooxanthellate, branching dendrophylliid Dendrophyllia arbuscula van der Horst 1922 , is a good species to investigate intrinsic regularities in budding, because: (1) the lateral corallites always occur in the vicinity of four primary septa, excluding the two directive primary septa; (2) the two directive septa in lateral corallites tend to be oriented almost perpendicular to the growth orientation of parental corallites; (3) the lateral corallites grow more‐or‐less diagonally upwards; and (4) these regularities are retained from the axial to the derived lateral corallites during colony growth. Accordingly, a colony of apparently complex dendroid corals is formed according to certain universal rules that apply to successive generations of corallites. The presence of two opposite sectors in which budding do not occur seems to be common to other azooxanthellate scleractinian families. Regularities, other than the orientation of the directive septa, are also commonly found at least in other azooxanthellate dendrophylliid genera. These regularities suggest the presence of strict developmental constraints on the asexual reproduction of the Scleractinia, both extant and extinct. These regularities by azooxanthellate scleractinians, as one of the representative colonial metazoan groups, provide us with fundamental data with which we can understand how colonies are constructed. □Azooxanthellate coral, budding, colony, Dendrophyllia arbuscula, regularity.     

Mate desertion by male Great Reed Warblers Acrocephalus arundinaceus at the end of the breeding season

Male Great Reed Warblers usually take part in the care of offspring as nest defenders and by feeding young, but at the end of the breeding season they desert their mates with eggs or nestlings. Deserted females continue offspring care. Desertion does not depend on the male's mated status (polygynous or monogamous) nor on his past breeding success. Deserted females compensate for the loss of their partners by increasing the frequency of food-bringing, resulting in a reduction in the amount of time the nestlings are brooded. Although desertion may lead to increased rates of offspring mortality through predation, breeding success of deserted females was high, especially if the male assisted during the early stages. Deserters pay costs by giving up the chance of additional matings and by lowering the reproductive success of existing mates. Male warblers reduce the former cost by choosing the season of desertion and the latter is lowered by the female's high parental ability. A deserter was found to start moulting while his mate was still feeding his nestlings, and an earlier start to the moult may be the primary benefit that he gains.     

Meiotic Protein in Spermatocytes of Mammals

THE DNA-binding protein in meiotic cells of Lilium¹ has a very high binding affinity for single stranded DNA and also the unusual property of catalysing the renaturation of thermally denatured lily DNA at room temperature. Significantly, these and other in vitro properties are very similar to those of the “gene 32-protein” which is essential to genetic recombination in T4 bacteriophage² and the possibility that this protein may have a function in meiotic recombination of Lilium led us to a more extensive study of its behaviour³.