Temporal tracking of mineralization and transcriptional developments of shell formation during the early life history of pearl oyster Pinctada maxima

Molluscan larval ontogeny is a highly conserved process comprising three principal developmental stages. A characteristic unique to each of these stages is shell design, termed prodissoconch I, prodissoconch II and dissoconch. These shells vary in morphology, mineralogy and microstructure. The discrete temporal transitions in shell biomineralization between these larval stages are utilized in this study to investigate transcriptional involvement in several distinct biomineralization events. Scanning electron microscopy and X-ray diffraction analysis of P. maxima larvae and juveniles collected throughout post-embryonic ontogenesis, document the mineralogy and microstructure of each shelled stage as well as establishing a timeline for transitions in biomineralization. P. maxima larval samples most representative of these biomineralization distinctions and transitions were analyzed for differential gene expression on the microarray platform PmaxArray 1.0. A number of transcripts are reported as differentially expressed in correlation to the mineralization events of P. maxima larval ontogeny. Some of those isolated are known shell matrix genes while others are novel; these are discussed in relation to potential shell formation roles. This interdisciplinary investigation has linked the shell developments of P. maxima larval ontogeny with corresponding gene expression profiles, furthering the elucidation of shell biomineralization

Values of veteran Israelis and new immigrants from the former Soviet Union: a facet analysis

"Grounded on the formal faceted definition of values introduced by Levy & Guttman (1974), a mapping sentence was constructed to define values as guiding principles. Guided by the Facet Theory approach, the perceptual structure of the value system as well as value preferences are reviewed in a comparative perspective: veteran Israelis vis-à-vis new immigrants from the former Soviet Union (FSU). The data are part of a comprehensive study on Israeli society (Levy, Levinsohn & Katz 2002), conducted between June 1999 and January 2000. Two samples were investigated by means of face-to-face interviews: a national sample of Jewish Israeli adults, consisting of 2,466 respondents, and a comparable representative sample of FSU immigrants, consisting of 373 respondents. FSU immigrants attribute less importance than do veteran Israelis to each of the values under study, but they do not differ much in their value preferences. Both groups share a basic similar circular structure of values (a radex) specified by the orientations of the values, thus replicating earlier studies on values. Differences in a few details are discussed." (author's abstract

Differential expression profiling of components associated with exoskeletal hardening in crustaceans

<p>Abstract</p> <p>Background</p> <p>Exoskeletal hardening in crustaceans can be attributed to mineralization and sclerotization of the organic matrix. Glycoproteins have been implicated in the calcification process of many matrices. Sclerotization, on the other hand, is catalysed by phenoloxidases, which also play a role in melanization and the immunological response in arthropods. Custom cDNA microarrays from <it>Portunus pelagicus </it>were used to identify genes possibly associated with the activation pathways involved in these processes.</p> <p>Results</p> <p>Two genes potentially involved in the recognition of glycosylation, the C-type lectin receptor and the mannose-binding protein, were found to display molt cycle-related differential expression profiles. C-type lectin receptor up-regulation was found to coincide with periods associated with new uncalcified cuticle formation, while the up-regulation of mannose-binding protein occurred only in the post-molt stage, during which calcification takes place, implicating both in the regulation of calcification. Genes presumed to be involved in the phenoloxidase activation pathway that facilitates sclerotization also displayed molt cycle-related differential expression profiles. Members of the serine protease superfamily, trypsin-like and chymotrypsin-like, were up-regulated in the intermolt stage when compared to post-molt, while trypsin-like was also up-regulated in pre-molt compared to ecdysis. Additionally, up-regulation in pre- and intermolt stages was observed by transcripts encoding other phenoloxidase activators including the putative antibacterial protein carcinin-like, and clotting protein precursor-like. Furthermore, hemocyanin, itself with phenoloxidase activity, displayed an identical expression pattern to that of the phenoloxidase activators, i.e. up-regulation in pre- and intermolt.</p> <p>Conclusion</p> <p>Cuticle hardening in crustaceans is a complex process that is precisely timed to occur in the post-molt stage of the molt cycle. We have identified differential expression patterns of several genes that are believed to be involved in biomineralization and sclerotization and propose possible regulatory mechanisms for these processes based on their expression profiles, such as the potential involvement of C-type lectin receptors and mannose binding protein in the regulation of calcification.</p

Gene expression profiling of cuticular proteins across the moult cycle of the crab Portunus pelagicus

Background: Crustaceans represent an attractive model to study biomineralization and cuticle matrix formation, as these events are precisely timed to occur at certain stages of the moult cycle. Moulting, the process by which crustaceans shed their exoskeleton, involves the partial breakdown of the old exoskeleton and the synthesis of a new cuticle. This cuticle is subdivided into layers, some of which become calcified while others remain uncalcified. The cuticle matrix consists of many different proteins that confer the physical properties, such as pliability, of the exoskeleton

Synthesis of anisotropic 3D nanomagnets for magnetic actuation and sensing in piezoelectric polyvinylidene fluoride towards magnetic nanogenerator device fabrication

The 3D geometry and anisotropic properties of magnetic nanostructures has been found to have a direct impact on their magnetization properties due to spatial coordinates and larger surface areas, which sheds new light on next-generation materials for advanced applications in magnetic energy harvesting. Our work presents novel pathways for the synthesis and assembly of multifunctional anisotropic 3D nanomagnets with various shapes and sizes with key attention to their anisotropic morphologies. We investigated the excellent properties of these new anisotropic 3D nanomagnets for the design of magnetic actuator systems and nanogenerators by embedding the 3D nanomagnets in a piezoelectric polyvinylidene fluoride (PVDF) polymer matrix. The 3D nanomagnets-PDVF composites were found to exhibit the highly electroactive β-phase with enhanced piezoelectric sensitivity. Further, the 3D nanomagnets-PDVF thin films have outstanding magnetic responsiveness and actuation capacity ideal for the fabrication of magnetic nanogenerators. These types of materials have a great deal of potential to generate sustainable alternative energy sources through harvesting and conversion of ubiquitous and residual low-frequency environmental magnetic noise into usable electricity

Synthesis of anisotropic 3D nanomagnets for magnetic actuation and sensing in piezoelectric polyvinylidene fluoride towards magnetic nanogenerator device fabrication

The 3D geometry and anisotropic properties of magnetic nanostructures has been found to have a direct impact on their magnetization properties due to spatial coordinates and larger surface areas, which sheds new light on next-generation materials for advanced applications in magnetic energy harvesting. Our work presents novel pathways for the synthesis and assembly of multifunctional anisotropic 3D nanomagnets with various shapes and sizes with key attention to their anisotropic morphologies. We investigated the excellent properties of these new anisotropic 3D nanomagnets for the design of magnetic actuator systems and nanogenerators by embedding the 3D nanomagnets in a piezoelectric polyvinylidene fluoride (PVDF) polymer matrix. The 3D nanomagnets-PDVF composites were found to exhibit the highly electroactive β-phase with enhanced piezoelectric sensitivity. Further, the 3D nanomagnets-PDVF thin films have outstanding magnetic responsiveness and actuation capacity ideal for the fabrication of magnetic nanogenerators. These types of materials have a great deal of potential to generate sustainable alternative energy sources through harvesting and conversion of ubiquitous and residual low-frequency environmental magnetic noise into usable electricity