A study on the energy source in the developing embryo of the mangrove horseshoe crab,Carcinoscorpius rotundicauda (Latreille)

The mangrove horseshoe crab, Carcinoscorpius rotundicauda, is an Asian species found in Malaysia. This ancient arthropod has a long incubational period during which it depends on various energy sources for both embryogenesis and organogenesis. This study describes the trend of energy utilization from the endogenous reserves by the developing embryos from 0 to 40 days of incubation (until the hatching of the larvae). The dry weight, insoluble protein, carbohydrate, glycogen and lipid showed a declining trend from 0 to 40 days of incubation, whereas the wet weight, water content, ash content and soluble protein showed an increasing trend. Selected micro-elements such as Cu²⁺, Fe²⁺ and Zn²⁺ also demonstrated an interesting trend in the developing eggs when the egg mass was subjected to inductively coupled plasma mass spectrometry analysis, where these elements showed a high correlation with the moulting stages and egg development. Maximum variations within the micro-elements were observed during the 1st (10 days after fertilization) and 2nd (35–36 days after fertilization) moulting stages within the developing eggs. This study clearly indicated that the moulting cycles of C. rotundicauda during embryonic development influence energy utilization in the form of carbohydrates, lipids, proteins, glycogen and other micro-elements.     

A diterpenoid derivate compound targets selenocysteine of thioredoxin reductases and induces Bax/Bak-independent apoptosis

We have previously shown that the natural diterpenoid derivative S3 induced Bim upregulation and apoptosis in a Bax/Bak-independent manner. However, the exact molecular target(s) of S3 and the mechanism controlling Bim upregulation are still not clear. Here, we identify that S3 targets the selenoproteins TrxR1 and TrxR2 at the selenocysteine residue of the reactive center of the enzymes and inhibits their antioxidant activities. Consequently, cellular ROS is elevated, leading to the activation of FOXO3a, which contributes to Bim upregulation in Bax/Bak-deficient cells. Moreover, S3 retards tumor growth in subcutaneous xenograft tumors by inhibiting TrxR activity in vivo. Our studies delineate the signaling pathway controlling Bim upregulation, which results in Bax/Bak-independent apoptosis and provide evidence that the compounds can act as anticancer agents based on mammalian TrxRs inhibition.     

Multifaceted applications of nanomaterials in cell engineering and therapy

Nanomaterials with superior physiochemical properties have been rapidly developed and integrated in every aspect of cell engineering and therapy for translating their great promise to clinical success. Here we demonstrate the multifaceted roles played by innovatively-designed nanomaterials in addressing key challenges in cell engineering and therapy such as cell isolation from heterogeneous cell population, cell instruction in vitro to enable desired functionalities, and targeted cell delivery to therapeutic sites for prompting tissue repair. The emerging trends in this interdisciplinary and dynamic field are also highlighted, where the nanomaterial-engineered cells constitute the basis for establishing in vitro disease model; and nanomaterial-based in situ cell engineering are accomplished directly within the native tissue in vivo. We will witness the increasing importance of nanomaterials in revolutionizing the concept and toolset of cell engineering and therapy which will enrich our scientific understanding of diseases and ultimately fulfill the therapeutic demand in clinical medicine.     

Differential maturation of rhythmic clock gene expression during early development in medaka (Oryzias latipes)

One key challenge for the field of chronobiology is to identify how circadian clock function emerges during early embryonic development. Teleosts such as the zebrafish are ideal models for studying circadian clock ontogeny since the entire process of development occurs ex utero in an optically transparent chorion. Medaka (Oryzias latipes) represents another powerful fish model for exploring early clock function with, like the zebrafish, many tools available for detailed genetic analysis. However, to date there have been no reports documenting circadian clock gene expression during medaka development. Here we have characterized the expression of key clock genes in various developmental stages and in adult tissues of medaka. As previously reported for other fish, light dark cycles are required for the emergence of clock gene expression rhythms in this species. While rhythmic expression of per and cry genes is detected very early during development and seems to be light driven, rhythmic clock and bmal expression appears much later around hatching time. Furthermore, the maturation of clock function seems to correlate with the appearance of rhythmic expression of these positive elements of the clock feedback loop. By accelerating development through elevated temperatures or by artificially removing the chorion, we show an earlier onset of rhythmicity in clock and bmal expression. Thus, differential maturation of key elements of the medaka clock mechanism depends on the developmental stage and the presence of the chorion.     

Hemiodus iratapuru,a new species of Hemiodontidae from the Rio Jari,Amazon Basin,Brazil (Teleostei,Characiformes)

Hemiodus iratapuru, a new species of the Hemiodontidae from the Rio Iratapuru, a left bank tributary of the Rio Jari, Amazon Basin, Brazil, is described. The new species is diagnosed from other species of Hemiodus by modifications in the ectopterygoid, tooth form, scale counts, dorsal‐fin form and colour pattern. The new species is proposed to be related to the Hemiodus quadrimaculatus species group.     

The ductal origin of structural and functional heterogeneity between pancreatic islets

Islets form in the pancreas after the first endocrine cells have arisen as either single cells or small cell clusters in the epithelial cords. These cords constitute the developing pancreas in one of its earliest recognizable stages. Islet formation begins at the time the cords transform into a branching ductal system, continues while the ductal system expands, and finally stops before the exocrine tissue of ducts and acini reaches its final expansion. Thus, islets continuously arise from founder cells located in the branching and ramifying ducts. Islets arising from proximal duct cells locate between the exocrine lobules, develop strong autonomic and sensory innervations, and pass their blood to efferent veins (insulo-venous efferent system). Islets arising from cells of more distal ducts locate within the exocrine lobules, respond to nerve impulses ending at neighbouring blood vessels, and pass their blood to the surrounding acini (insulo-acinar portal system). Consequently, the section of the ductal system from which an islet arises determines to a large extent its future neighbouring tissue, architecture, properties, and functions. We note that islets interlobular in position are frequently found in rodents (rats and mice), whereas intralobularly-located, peripheral duct islets prevail in humans and cattle. Also, we expound on bovine foetal Laguesse islets as a prominent foetal type of type 1 interlobular neuro-insular complexes, similar to neuro-insular associations frequently found in rodents. Finally, we consider the probable physiological and pathophysiological implications of the different islet positions within and between species.     

Neural differentiation of human embryonic stem cells as an in vitro tool for the study of the expression patterns of the neuronal cytoskeleton during neurogenesis

The neural differentiation of human embryonic stem cells (ESCs) is a potential tool for elucidating the key mechanisms involved in human neurogenesis. Nestin and β-III-tubulin, which are cytoskeleton proteins, are marker proteins of neural stem cells (NSCs) and neurons, respectively. However, the expression patterns of nestin and β-III-tubulin in neural derivatives from human ESCs remain unclear. In this study, we found that neural progenitor cells (NPCs) derived from H9 cells express high levels of nestin and musashi-1. In contrast, β-III-tubulin was weakly expressed in a few NPCs. Moreover, in these cells, nestin formed filament networks, whereas β-III-tubulin was distributed randomly as small particles. As the differentiation proceeded, the nestin filament networks and the β-III-tubulin particles were found in both the cell soma and the cellular processes. Moreover, the colocalization of nestin and β-III-tubulin was found mainly in the cell processes and neurite-like structures and not in the cell soma. These results may aid our understanding of the expression patterns of nestin and β-III-tubulin during the neural differentiation of H9 cells.     

Screening for Protein-producing Bacteria

Screening of protein-producing bacteria was conducted to systematically study the ubiquitous nature of the extracellular production of proteins and their excretion mechanisms. A very simple and efficient test revealed that about 15% of bacteria tested (total 1200 strains) accumulated some protein under the cultural conditions employed. Among protein-excretors, five strains produced a large amount of protein in the liquid shake culture.

Many good protein producers including five excellent ones were found to be gram-positive rod and probably belong to Bacillus species. An acid-insoluble product by one of the hyper-protein producers was identified as a protein mixture. Good producer was not found among the known 15 species of bacteria. The implication of these findings is discussed.     

Embryonic lethality leads to hybrid male inviability in hybrids between Drosophila melanogaster and D. santomea

The study of the morphological defects unique to interspecific hybrids can reveal which developmental pathways have diverged between species. Drosophila melanogaster and D. santomea diverged more than 10 million years ago, and when crossed produce sterile adult females. Adult hybrid males are absent from all interspecific crosses. We aimed to determine the fate of these hybrid males. To do so, we tracked the development of hybrid females and males using classic genetic markers and techniques. We found that hybrid males die predominantly as embryos with severe segment‐specification defects while a large proportion of hybrid females embryos hatch and survive to adulthood. In particular, we show that most male embryos show a characteristic abdominal ablation phenotype, not observed in either parental species. This suggests that sex‐specific embryonic developmental defects eliminate hybrid males in this interspecific cross. The study of the developmental abnormalities that occur in hybrids can lead to the understanding of cryptic molecular divergence between species sharing a conserved body plan.