PROBAVNI SUSTAV KOŠTUNJAČA PERSORBIRA MIKROČESTICE

The ability of the teleost gut to absorb microparticulate material was examined following rectal intubation (3.5 g kg -1 ) of commercial grade cornstarch (≈21 mm diameter), or potato starch (≈43 mm diameter). Tissue samples were taken from the mid - and hind-gut of control and treated fish 18 h postintubation. Collected samples were processed using standard plastic and staining protocols and resultant photomicrographs examined by computer-assisted image analysis. Cornstarch particles (8-14 mm), were observed to pass from gut lumen to the lamina propria via a paracellular or persorptive route only. No evidence for the like passage of potato starch was found.Mogućnost probavnog sustava koštunjavičastih vrsta riba da apsorbiraju sitne čestice pojedinih tvari bila je istraživana s pomoću rektalne intubacije (3, 5 g kg -1 ) komercijalnoga škroba kukuruza (promjera ≈21 mm) i škroba krumpira (promjera ≈ 43 mm). Uzorci tkiva uzeti su iz srednjeg i stražnjeg dijela crijeva kontrolne i tretirane skupine riba, i to 18 sati nakon intubacije. Sakupljeni su uzorci spremljeni u standardne plastike i obojeni prema protokolu, te fotomikrografski snimljeni na računalu. Čestice škroba kukuruza (8-14 mm) zapažene su da iz lumena crijeva prolaze u laminu propriju samo paracelularnim ili persorptivnim putem. No, nije zapažen prolazak čestica škroba krumpira

PROBAVNI SUSTAV KOŠTUNJAČA PERSORBIRA MIKROČESTICE

The ability of the teleost gut to absorb microparticulate material was examined following rectal intubation (3.5 g kg -1 ) of commercial grade cornstarch (≈21 mm diameter), or potato starch (≈43 mm diameter). Tissue samples were taken from the mid - and hind-gut of control and treated fish 18 h postintubation. Collected samples were processed using standard plastic and staining protocols and resultant photomicrographs examined by computer-assisted image analysis. Cornstarch particles (8-14 mm), were observed to pass from gut lumen to the lamina propria via a paracellular or persorptive route only. No evidence for the like passage of potato starch was found.Mogućnost probavnog sustava koštunjavičastih vrsta riba da apsorbiraju sitne čestice pojedinih tvari bila je istraživana s pomoću rektalne intubacije (3, 5 g kg -1 ) komercijalnoga škroba kukuruza (promjera ≈21 mm) i škroba krumpira (promjera ≈ 43 mm). Uzorci tkiva uzeti su iz srednjeg i stražnjeg dijela crijeva kontrolne i tretirane skupine riba, i to 18 sati nakon intubacije. Sakupljeni su uzorci spremljeni u standardne plastike i obojeni prema protokolu, te fotomikrografski snimljeni na računalu. Čestice škroba kukuruza (8-14 mm) zapažene su da iz lumena crijeva prolaze u laminu propriju samo paracelularnim ili persorptivnim putem. No, nije zapažen prolazak čestica škroba krumpira

The Deep Sea and Sub-Seafloor Frontier

The deep sea and its sub-seafloor contain a vast reservoir of physical, mineral and biological resources that are rapidly coming into the window of exploitation. Assessing the opportunities and the risks involved requires a serious commitment to excellent deep sea research. There are numerous areas in this field in which Europe has cutting-edge technological potential. These include drilling and monitoring technology in the field of renewable energies such as geothermal, offshore wind and seafloor resources. Scientific ocean drilling will continue to play a valuable role, for example in the exploration of resource opportunities, in obtaining estimates for ecosystem and Earth climate sensitivity, or in improving understanding about the controlling factors governing processes and recurrence intervals of submarine geohazards. In Europe, there is also the scientific expertise needed to define a framework for policymakers for environmental protection measures and to carry out ecological impact assessments before, during and after commercial exploitation. Taking up these societal challenges will strengthen European scientific and educational networks and promote the development of world-class technology and industrial leadership.Published3.7. Dinamica del clima e dell'oceano4.6. Oceanografia operativa per la valutazione dei rischi in aree marineope

Subspace-based damage detection on steel frame structure under changing excitation

International audienceDamage detection can be performed by detecting changes in the modal parameters between a reference state and the current (possibly damaged) state of a structure from measured output-only vibration data. Alternatively, a subspace-based damage detection test has been proposed and applied successfully, where changes in the modal parameters are detected, but the estimation of the modal parameters themselves is avoided. Like this, the test can run in an automated way directly on the vibration measurements. However, it was assumed that the unmeasured ambient excitation properties during measurements of the structure in the reference and possibly damaged condition stay constant, which is hardly satisfied by any application. A new version of the test has been derived recently that is robust to such changes in the ambient excitation. In this paper, the robust test is recalled and its performance is evaluated both on numerical simulations and a real application, where a steel frame structure is artificially damaged in the lab

Transcriptional analysis of the HeT-A retrotransposon in mutant and wild type stocks reveals high sequence variability at Drosophila telomeres and other unusual features

<p>Abstract</p> <p>Background</p> <p>Telomere replication in Drosophila depends on the transposition of a domesticated retroelement, the <it>HeT-A </it>retrotransposon. The sequence of the <it>HeT-A </it>retrotransposon changes rapidly resulting in differentiated subfamilies. This pattern of sequence change contrasts with the essential function with which the <it>HeT-A </it>is entrusted and brings about questions concerning the extent of sequence variability, the telomere contribution of different subfamilies, and whether wild type and mutant Drosophila stocks show different <it>HeT-A </it>scenarios.</p> <p>Results</p> <p>A detailed study on the variability of <it>HeT-A </it>reveals that both the level of variability and the number of subfamilies are higher than previously reported. Comparisons between GIII, a strain with longer telomeres, and its parental strain Oregon-R indicate that both strains have the same set of <it>HeT-A </it>subfamilies. Finally, the presence of a highly conserved splicing pattern only in its antisense transcripts indicates a putative regulatory, functional or structural role for the <it>HeT-A </it>RNA. Interestingly, our results also suggest that most <it>HeT-A </it>copies are actively expressed regardless of which telomere and where in the telomere they are located.</p> <p>Conclusions</p> <p>Our study demonstrates how the <it>HeT-A </it>sequence changes much faster than previously reported resulting in at least nine different subfamilies most of which could actively contribute to telomere extension in Drosophila. Interestingly, the only significant difference observed between Oregon-R and GIII resides in the nature and proportion of the antisense transcripts, suggesting a possible mechanism that would in part explain the longer telomeres of the GIII stock.</p

Enhancement of Penaeus monodon shrimp postlarvae growth and survival without water exchange using marine Bacillus pumilus and periphytic microalgae.

We have investigated the possibility of using a consortium of marine bacterium and periphytic microalgae to improve the water quality and increase the growth and survival of the shrimp Penaeus monodon in a hatchery system. Three treatments were evaluated for their effect on P. monodon postlarvae (PL) when the culture water was not changed: Bacillus pumilus alone (B); periphytic microalgae alone (M); B. pumilus + periphytic microalgae (BM). P. monodon PL raised in a tank of unchanged water without bacterium and periphytic microalgae served as the control. The water in tanks of the M and BM treatments had significantly low levels of total ammonia-nitrogen (TAN) (0.03 and 0.01 mg l−1, respectively) and nitrite-nitrogen (NO2-N) (0.03, 0.01 mg l−1, respectively) than that in the B (TAN 0.80, NO2-N 0.68 mg l−1) and control (TAN 1.11, NO2-N 1.12 mg l−1) tanks. Moreover, PL cultured in tanks M and BM had significantly higher survival and specific growth rates and a significantly higher resistance to the reverse salinity stress test than those in the B and control tanks. Compared to the control PL, the PL cultured in the BM tanks had significantly higher levels of protein, lipid, polyunsaturated fatty acids, ecosapentaenoic acid, and docosahexaenoic acid. The culture water in tanks BM also contained significantly less Vibrio than the control water. Our results illustrate the beneficial effects of a B. pumilus and periphytic microalgae consortium on improving the water quality and the growth and survival of shrimp PL grown in a hatchery system

Identification of a Bipotential Precursor Cell in Hepatic Cell Lines Derived from Transgenic Mice Expressing Cyto-Met in the Liver

Met murine hepatocyte (MMH) lines were established from livers of transgenic mice expressing constitutively active human Met. These lines harbor two cell types: epithelial cells resembling the parental populations and flattened cells with multiple projections and a dispersed growth habit that are designated palmate. Epithelial cells express the liver-enriched transcription factors HNF4 and HNF1α, and proteins associated with epithelial cell differentiation. Treatments that modulate their differentiation state, including acidic FGF, induce hepatic functions. Palmate cells show none of these properties. However, they can differentiate along the hepatic cell lineage, giving rise to: (a) epithelial cells that express hepatic transcription factors and are competent to express hepatic functions; (b) bile duct-like structures in three-dimensional Matrigel cultures. Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells. Furthermore, karyotype analysis confirms the direction of the phenotypic transition: palmate cells are diploid and the epithelial cells are hypotetraploid. The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development

Expression of Drosophila virilis Retroelements and Role of Small RNAs in Their Intrastrain Transposition

Transposition of two retroelements (Ulysses and Penelope) mobilized in the course of hybrid dysgenesis in Drosophila virilis has been investigated by in situ hybridization on polytene chromosomes in two D. virilis strains of different cytotypes routinely used to get dysgenic progeny. The analysis has been repeatedly performed over the last two decades, and has revealed transpositions of Penelope in one of the strains, while, in the other strain, the LTR-containing element Ulysses was found to be transpositionally active. The gypsy retroelement, which has been previously shown to be transpositionally inactive in D. virilis strains, was also included in the analysis. Whole mount is situ hybridization with the ovaries revealed different subcellular distribution of the transposable elements transcripts in the strains studied. Ulysses transpositions occur only in the strain where antisense piRNAs homologous to this TE are virtually absent and the ping-pong amplification loop apparently does not take place. On the other hand small RNAs homologous to Penelope found in the other strain, belong predominantly to the siRNA category (21nt), and consist of sense and antisense species observed in approximately equal proportion. The number of Penelope copies in the latter strain has significantly increased during the last decades, probably because Penelope-derived siRNAs are not maternally inherited, while the low level of Penelope-piRNAs, which are faithfully transmitted from mother to the embryo, is not sufficient to silence this element completely. Therefore, we speculate that intrastrain transposition of the three retroelements studied is controlled predominantly at the post-transcriptional level