No abstract available

[en] Progress is reported on the following studies: methods of collecting sea cucumbers; determination of growth rates of plates of the calcareous ring; use of growth parameters and a length-frequency distribution to estimate mortality and population turnover; movement of materials through the atoll ecosystem; and autoradiographic studies on spines of sea urchins

No abstract available

[en] Highlights: • Sea urchin anomalies, caused by multiple stressors, can be grouped into 18 types. • Anomaly severity and evolution depend on stressor concentration/intensity. • Stressors cause similar anomalies impinging on the same cellular mechanisms. • Embryo and larval anomalies can be used to predict the environmental impact degree. The morphological anomalies of the early development stages of the sea urchin Paracentrotus lividus, caused by exposure to environmental stressors, are used as biomarker in ecotoxicological and ecological investigations. Here, we reviewed the available literature and classified the embryo and larval anomalies identified so far, to highlight potential commonalities or differences related to the biological action of the different stressors and their ecological impact. Morphological anomalies are influenced by a) the developmental stage of exposure to stressors; b) the intensity of the stress; c) the intra- and inter-cellular mechanisms affected by the exposure to environmental agents. The classification and analysis of embryo and larvae anomalies, either observed by the authors of this review and reported in literature, indicate that sea urchin abnormalities, caused by exposure to different stressors, can be very similar among them and classified into 18 main types, which can occur individually or mixed. All anomalies can be used to calculate an Index of Contaminant Impact to assess the impact of multiple stressors and to identify relationships between morphological anomalies and compromised biological mechanisms. This approach could be useful for a first screening of the presence of potential stressors impairing the growth and development of the early life stages of marine organisms, thus providing a relevant advancement for in future monitoring activities devoted to assess the health status in coastal marine ecosystems.

[en] Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic

[en] Treatment with heavy metals, such as nickel, lead or cadmium, elicits different cellular stress responses according to the metal used and the length of treatment. In Paracentrotus lividus embryos the inducible forms of HSP70 (HSP70/72) are different in molecular mass from the constitutively expressed HSP75, and they can be used as markers of cellular stress. Even a short treatment with each metal induces the synthesis of HSP70/72 which remain stable for at least 20 h and differ little in their isoelectric points. Continuous treatment from fertilization with nickel or lead produces late irregular pluteus embryos, with peak HSP70/72 synthesis at blastula followed by the arrest of synthesis by pluteus. On the contrary, the same treatment with cadmium induces continuous HSP70/72 synthesis and produces irregular gastrula embryos which then degenerate. Moreover, a long treatment induces over control embryos a slight increase in the amount of constitutive HSP75 during development while lead treatment depresses constitutive HSP75 at early stages and doubles its quantity at late stages

[en] Being structural analogues of natural microtubule-destabilizing cytostatics, polyalkoxyflavonoids represent a promising class of compounds for anticancer drug design. The review covers synthetic routes to various polyalkoxyflavonoids and the results of biological assays in vitro on human cancer cells and in vivo using sea urchin embryos as a model. Mechanisms of action and structure–relationship activity for polyalkoxyflavonoids are discussed. The bibliography includes 151 references

[en] Biological systems such as single cells must function in the presence of fluctuations. It has been shown in a two-dimensional experimental setup that sea urchin sperm cells move toward a source of chemoattractant along planar trochoidal swimming paths, i.e. drifting circles. In these experiments, a pronounced variability of the swimming paths is observed. We present a theoretical description of sperm chemotaxis in two dimensions which takes fluctuations into account. We derive a coarse-grained theory of stochastic sperm swimming paths in a concentration field of chemoattractant. Fluctuations enter as multiplicative noise in the equations for the sperm swimming path. We discuss the stochastic properties of sperm swimming and predict a concentration-dependence of the effective diffusion constant of sperm swimming which could be tested in experiments.

[en] The type of feeding habit, size spectrum (megalo-, macro-, meio-, and micro-benthos), life form (epi-, and endo-biose) and other modes of living of benthic organisms on and within the bottom sediments are briefly mentioned. Knowledge hitherto obtained concerning radio-ecology is also briefly reviewed in relation to those items mentioned above. Special attention is given to the relationship between the stratification and the mixing of bottom deposits, and the reworking and feeding activities of benthic animals. (auth.)

[en] Highlights: • 30-year changes in coral communities were studied along with pollution events. • Severe coral degradations in 1980s had stopped in inner harbour after 1998. • Outer coral communities continued to decline at a similar rate as in 1980s. • Coral recovery was limited by low recruitment success. • Coral communities could be destroyed easily, yet recovery could be so difficult. - Abstract: Coral communities in Tolo Harbour and Channel, northeastern Hong Kong, suffered from tremendous degradations in 1980s due to excessive sewage pollutions. This study examined changes in coral community structures over the last 30 years including period before, at the height of and after implementation of abatement measures of pollution impacts. Signs of coral degradations finally stopped in inner harbour and some corals started to reappear, likely due to sewage export scheme since 1998. Yet, the coral cover remained very low (Oulastrea crispata. The outer coral communities, which suffered least in 1980s, continued to decline, possibly due to new biological disturbances like sea urchin predation and bioerosion. This long-term study clearly revealed how coral communities could so easily be destroyed and yet natural recovery could be so difficult and unlikely.