Early development and neurogenesis of Temnopleurus reevesii

Sea urchins are model non‐chordate deuterostomes, and studying the nervous system of their embryos can aid in the understanding of the universal mechanisms of neurogenesis. However, despite the long history of sea urchin embryology research, the molecular mechanisms of their neurogenesis have not been well investigated, in part because neurons appear relatively late during embryogenesis. In this study, we used the species Temnopleurus reevesii as a new sea urchin model and investigated the detail of its development and neurogenesis during early embryogenesis. We found that the embryos of T. reevesii were tolerant of high temperatures and could be cultured successfully at 15–30°C during early embryogenesis. At 30°C, the embryos developed rapidly enough that the neurons appeared at just after 24 h. This is faster than the development of other model urchins, such as Hemicentrotus pulcherrimus or Strongylocentrotus purpuratus. In addition, the body of the embryo was highly transparent, allowing the details of the neural network to be easily captured by ordinary epifluorescent and confocal microscopy without any additional treatments. Because of its rapid development and high transparency during embryogenesis, T. reevesii may be a suitable sea urchin model for studying neurogenesis. Moreover, the males and females are easily distinguishable, and the style of early cleavages is intriguingly unusual, suggesting that this sea urchin might be a good candidate for addressing not only neurology but also cell and developmental biology.     

Prosody Discrimination by Songbirds (Padda oryzivora)

In human verbal communication, not only lexical information, but also paralinguistic information plays an important role in transmitting the speakers’ mental state. Paralinguistic information is conveyed mainly through acoustic features like pitch, rhythm, tempo and so on. These acoustic features are generally known as prosody. It is known that some species of birds can discriminate certain aspects of human speech. However, there have not been any studies on the discrimination of prosody in human language which convey different paralinguistic meanings by birds. In the present study, we have shown that the Java sparrow (Padda oryzivora) can discriminate different prosodic patterns of Japanese sentences. These birds could generalize prosodic discrimination to novel sentences, but could not generalize sentence discrimination to those with novel prosody. Moreover, unlike Japanese speakers, Java sparrows used the first part of the utterance as the discrimination cue.     

Submovement Composition of Head Movement

Limb movement is smooth and corrections of movement trajectory and amplitude are barely noticeable midflight. This suggests that skeletomuscular motor commands are smooth in transition, such that the rate of change of acceleration (or jerk) is minimized. Here we applied the methodology of minimum-jerk submovement decomposition to a member of the skeletomuscular family, the head movement. We examined the submovement composition of three types of horizontal head movements generated by nonhuman primates: head-alone tracking, head-gaze pursuit, and eye-head combined gaze shifts. The first two types of head movements tracked a moving target, whereas the last type oriented the head with rapid gaze shifts toward a target fixed in space. During head tracking, the head movement was composed of a series of episodes, each consisting of a distinct, bell-shaped velocity profile (submovement) that rarely overlapped with each other. There was no specific magnitude order in the peak velocities of these submovements. In contrast, during eye-head combined gaze shifts, the head movement was often comprised of overlapping submovements, in which the peak velocity of the primary submovement was always higher than that of the subsequent submovement, consistent with the two-component strategy observed in goal-directed limb movements. These results extend the previous submovement composition studies from limb to head movements, suggesting that submovement composition provides a biologically plausible approach to characterizing the head motor recruitment that can vary depending on task demand.     

Classification,Based on Autonomous Fluorescence,of the Blood Cells of Several Ascidians that Contain High Levels of Vanadium

Ascidians are known to have the unique ability to accumulate vanadium in their blood cells. Classification of the various types of blood is, however, the subject of some controversy. In the present study we found that the various types of blood cell can be classified on the basis of their autonomous fluorescence upon excitation with blue-violet light. This method was of particular practical value in the classification of the vacuolated cells that account for about 80% of the total population of cells and are distinguished by their ability to accumulate vanadium.     

Metabolic pathways of carotenoids in chum salmon Oncorhynchus keta during spawning migration

1. Based on the contents and individual composition of carotenoids in the muscle, serum and ovaries of chum salmon during spawning migration, the reductive metabolism of astaxanthin to zeaxanthin was presumed to take place in the muscle of both male and female. 2. The metabolic rates of zeaxanthin and 4-keto-zeaxanthin in female serum were much faster than those in male serum.     

Possible involvement of cathepsin L in processing of rat liver hexokinase to eliminate mitochondria-binding ability.

A previously found proteinase possibly involved in the modification of hexokinase to eliminate the mitochondria-binding ability without appreciable change in the catalytic activity (called hexokinase-processing enzyme hereafter), was purified by sequential chromatographies from rat liver and its properties were examined. The hexokinase-processing enzyme had carbohydrate moieties as evidenced by adsorption on immobilized concanavalin A, and had a molecular weight of about 23,000 as estimated by SDS-PAGE and gel filtration chromatography. Benzyloxycarbonyl-phenylalanyl-L-arginine-4-methylcoumaryl-7-amide (Z-Phe-Arg-MCA)-hydrolyzing activity was co-purified with this processing activity throughout the purification, while the hydrolyzing activity for benzyloxycarbonyl-L-arginyl-L-arginine-4-methylcoumaryl-7-amide (Z-Arg-Arg-MCA) was not. The processing activity, as well as Z-Phe-Arg-MCA hydrolyzing activity, was highly sensitive to cysteine proteinase inhibition, for example, by leupeptin and N-[N-3-(trans-carboxirane-2-carbonyl)-L-leucyl]agmatine (E-64). Furthermore, the enzyme preparation reacted with an antibody against cathepsin L purified from rat kidney. These results indicated that cathepsin L may be involved in the above-mentioned processing of hexokinase.     

The augmentation of tumor-specific immunity using haptenic muramyl dipeptide (MDP) derivatives

Summary A new haptenic compound, a muramyl dipeptide (MDP) derivative (designated as L4-MDP-ONB) cross-reactive with Bacillus Calmette Guerin (BCG) was synthesized. The cross-reactivity of L4-MDP hapten to BCG was demonstrated from the following evidence; (a) lymph node cells from BCG-primed C3H/HeN mice exhibited appreciable L4-MDP-specific proliferative responses to the in vitro stimulation of L4-MDP-modified syngeneic cells (L4-MDP-self); (b) inoculation of L4-MDP-self into footpads of BCG-primed C3H/HeN mice elicited ample delayed type-hypersensitivity (DTH) responses in vivo as measured by footpad swelling; and (c) BCG-primed mice contained L4-MDP-reactive helper T cell activity which functions to augment the generation of effector T cell responses to cell surface antigens. This crossreactivity between L4-MDP hapten and BCG as measured by the helper T cell activity was applied to enhanced induction of tumor-specific immunity. When BCG-primed C3H/HeN mice were immunized with L4-MDP-modified syngeneic X5563 tumor cells, these mice could generate augmented tumor-specific in vivo protective (tumor neutralizing) immunity as well as in vitro cytotoxic T cell responses. These results indicate the effectiveness of L4-MDP hapten in augmenting tumor-specific immunity. The present approach is discussed in the context of potential advantages of this new hapten for its future application to clinical tumor systems.