Succession of sessile organisms on experimental plates immersed in Nabeta Bay,Izu Peninsula,Japan V. An integrated consideration on the definition and prediction of succession

Successional changes of sessile organisms over about 3 years on concrete plates immersed at depths of 1.0, 2.5, 4.0 and 5.5 m in Nabeta Bay, Shimoda, Pacific coast of Japan, were investigated from their species composition, percentage cover, and the structure, metabolism, biomass and maturity of the community for the purpose of verifying the hypothesis of succession by Margalef (1968) and Odum (1969). The process of succession was divided into five stages from a cluster analysis based on Horn's (1966) similarity in community structure. The five stages were characterized from dominant, species and 18 community attributes in terms of structure, metabolism, biomass and maturity. With the advance of stages, two large-sized, long-lived species, the kelpEisenia bicyclis and the oysterCrassostrea nippona, dominated; 18 community attributes showed a directional succession ending in a constant community structure, low community metabolism, accumulation of community biomass except chlorophylla and an enhanced degree of community maturity. This directionality in succession of community attributes was valid for the prediction of Margalef and Odum, despite a tendency for estimated daily energy budget to be more heterotrophic in such an open system. From these results, it was suggested that the definition of succession by Odum (1969) should be interpreted as the regularity in shift of dominant species, not individual species, and as the control of system by feedback mechanism developing with succession rather than community-controlled mechanism.     

Particularites biologiques et ecologiques du Rotifere Sinantherina socialis (Linne)

Resume Le Rotifère épiphyte et colonial Sinantherina socialis (Linné) prolifère dans la Loire depuis quelques années. Ses caractéristiques biologiques et écologiques ont été étu-diées au laboratoire et sur le terrain.Malgré une répartition des pontes régulière dans le temps, les éclosions manifestent une rythmicité liée a la photopériode. La determination des durées de dévelop-pement embryonnaire et post-embryonnaire, du rythme de ponte, de la dúree de la période de sénilité et de la durée de vie à différentes températures montrent que cette espèce se développe entre 18 et 34°C, avec un optimum à 27°C.Le cycle sexué se caractérise par l'existence de femelle amphoteres, capables d'émettre des oeufs femelles, apparemment amictiques, après avoir produit des oeufs mâles. L'apparition de la micticité est Re aux photopériodes courtes et aux fortes densités de population. Des températures suffisamment élevées (plus de 18°C) ont permis d'obtenir au laboratoire jusqu'à 80% d'éclosions parmi les oeufs de duree.

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The periphytic and colonial Rotifer Sinantherina socialis is a thermophile species living between 18 and 34°C. The hatching of its eggs takes place daily with a rhythm linked to the photoperiod. The sexual cycle is characterized by the existence of amphoteric females producing two kinds of eggs. The occurence of mictic eggs appeared to be significantly related to short photoperiods and great densities of population.Summary The periphytic and colonial Rotifer Sinantherina socialis has been swarming in the river Loire every summer for some years. Its biological and ecological characteristics have been studied in the laboratory and in the field.Although the eggs are laid regularly in time, the hatching occurs daily with a rhythm linked to the photoperiod. It occurs about 10 hours after the beginning of the light-period with a 16–8 (LD) photoperiod, 11 hours with a 14–10 photoperiod and 12 hours with a 12–12 photoperiod. To explain this hatching synchronisation and shift in time, the existence of a substance synthesized in the egg by night and destroyed by light might be assumed. The mature eggs would be sensitive to this substance, which would have the effect of delaying the hatching.Measurements of the duration of embryonic and post-embryonic development, of the frequency of laying eggs, of the duration of the senility period and of the duration of life, show that this species can grow between 18 and 34°C, the optimum being 27°C.The sexual cycle is characterized by the existence of amphoteric females, capable to emit apparently amictic eggs, after having produced male eggs. The occurrence of mictic reproduction appeared to be significantly related to short photoperiods and great densities of population. Sufficiently high temperatures (more than 18°C) allowed 80 per cent of hatching among the resting eggs in laboratory cultures.

     

宝铎草和长穗开口箭的核型

本文对湖南产的宝锋草（ＤｉｓｐｏｒｕｍｓｅｓｓｉｌｅＤ．Ｄｏｎ）和广西产的长穗开口箭（ＴｕｐｉｓｔｒａｌｏｎｇｉｓｐｉｃｇＹ．ＷａｎｅｔＸ．Ｈ．Ｌｕ）的核型作了分析。前者的核型公式为２ｎ＝１４＝４ｇ＋１０ｓｍ（２ｓａｔ）,核型类型属于３Ａ;后者的核型公式为２ｎ＝３８＝２４ｍ＋６ｓｉｎ＋８ｓｔ．核型具有明显的二型性,属于２Ｃ型。此外还讨论了宝锋草的核型变异以及开口箭属和蜘蛛抱蛋属（Ａｓｐｉｄｉｓｔｒａ）的关系。     

The effect of different media and culture techniques on plating efficiency of strawberry mesophyll cells in culture

Mesophyll cells of strawberry were isolated mechanically by a hand homogenizer, One g healthy, fully-expanded leaves yielded 10⁷ cells. The agar culture method was the only culture technique found suitable to obtain any quantitative data.     

Comparative analysis of the methods used for finding surface energy to investigate protein interaction behavior on chromatographic supports

Hydrophobic interaction chromatography, an important and effective purification strategy, is generally used for the purification of variety of biomolecules. A basic understanding of the protein interaction behavior is required to effectively separate these biomolecules. A colloidal type extended Derjaguin, Landau, Verwey, and Overbeek calculations were utilized to study the interactions behavior of model proteins to commercially available hydrophobic chromatographic materials that is, Toyopearl Phenyl 650C and Toyopearl Butyl 650C. Physicochemical properties of selected model proteins were achieved by contact angle and zeta potential measurements. The contact angle of chromatographic materials used was achieved through sessile drop method on disrupted beads and capillary penetration method (CPM) on intact beads. The surface properties were further used to calculate the interactions of the proteins to chromatographic supports. The calculated secondary energy minimum of the proteins with the chromatographic materials (from the contact angle values determined through both methods can be correlated with the retention volumes from the real chromatography. The secondary energy minimum values are higher for each protein to the chromatographic materials calculated from the inputs derived through sessile drop method compared to CPM. For instance, immunoglobulin G has secondary energy minimum value of 0.17 kT compared to 0.11 kT, obtained through sessile drop method and CPM, respectively. Average relative values of the energy minimum calculated for all proteins are as 1.51 kT and 1.29 kT for Toyopearl Butyl 650C and Toyopearl Phenyl 650C, respectively, as a conversion factor for estimation of secondary energy minimum for both methods.     

Starting the invasion pathway: the interaction between source populations and human transport vectors

Human transport hubs, such as shipping ports, airports and mail centers are important foci for the spread of non-indigenous species. High relative abundance in a transport hub has been proposed as a correlate of invasion success, since abundant species are thought more likely to colonize vectors and to be transported more frequently. We here evaluate the relative importance of vector characteristics and local source assemblages in determining the pool of species that is transported by hull fouling on recreational boats. We compared the resident fouling communities of three recreational boat harbors in Australia with the assemblages on the hulls of boats that travel between them. We used data on the recent travel and maintenance history of the boats to evaluate correlates of transport probability and the potential for intra-coastal spread of fouling organisms. Invertebrate assemblages on heavily fouled vessels reflected the composition of biotic assemblages within the marina in which they were moored, but by itself, relative abundance in the source port was not a reliable predictor of transport probability. More important was the age of the antifouling paint on the vessels’ hulls, which acted selectively on some groups of organisms. Movements of vessels were characterized by “fidelity” (vessels remaining close to homeport) interspersed with “promiscuity” (vessels traveling to a diverse pool of destinations). In an infested harbor, measures taken to increase the resistance of vectors to colonization by the invader should be effective in slowing the rate of spread to other locations, by decreasing the overall frequency of transport.     

Species specificity of barnacle settlement-inducing proteins

We previously isolated a larval settlement-inducing protein complex (SIPC) from adult extracts of the barnacle, Balanus amphitrite using a nitrocellulose membrane settlement assay. In the present study, we found that the extracts of other adult barnacles, Megabalanus rosa and Balanus eburneus, also induced the settlement of B. amphitrite cyprids although the inductive activity was slightly lower than that of conspecific extracts. Furthermore, we examined reactivity to anti-SIPC antibody in adult extracts from six species of Japanese barnacles other than B. amphitrite, brine shrimp and eight marine sessile organisms besides barnacles. The results showed that all barnacles examined contained SIPC-like proteins with slightly different molecular weight, while the other animals did not react to the antibody by immunoblot analysis. These findings suggest that species specificity in settlement-inducing proteins of barnacles is not so strict, but these proteins are characteristic to barnacle species.     

Current perspectives in pulmonary surfactant — Inhibition, enhancement and evaluation

Pulmonary surfactant (PS) is a complicated mixture of approximately 90% lipids and 10% proteins. It plays an important role in maintaining normal respiratory mechanics by reducing alveolar surface tension to near-zero values. Supplementing exogenous surfactant to newborns suffering from respiratory distress syndrome (RDS), a leading cause of perinatal mortality, has completely altered neonatal care in industrialized countries. Surfactant therapy has also been applied to the acute respiratory distress syndrome (ARDS) but with only limited success. Biophysical studies suggest that surfactant inhibition is partially responsible for this unsatisfactory performance. This paper reviews the biophysical properties of functional and dysfunctional PS. The biophysical properties of PS are further limited to surface activity, i.e., properties related to highly dynamic and very low surface tensions. Three main perspectives are reviewed. (1) How does PS permit both rapid adsorption and the ability to reach very low surface tensions? (2) How is PS inactivated by different inhibitory substances and how can this inhibition be counteracted? A recent research focus of using water-soluble polymers as additives to enhance the surface activity of clinical PS and to overcome inhibition is extensively discussed. (3) Which in vivo, in situ, and in vitro methods are available for evaluating the surface activity of PS and what are their relative merits? A better understanding of the biophysical properties of functional and dysfunctional PS is important for the further development of surfactant therapy, especially for its potential application in ARDS.     

Do low oxygen environments facilitate marine invasions? Relative tolerance of native and invasive species to low oxygen conditions

Biological invasions are one of the biggest threats to global biodiversity. Marine artificial structures are proliferating worldwide and provide a haven for marine invasive species. Such structures disrupt local hydrodynamics, which can lead to the formation of oxygen‐depleted microsites. The extent to which native fauna can cope with such low oxygen conditions, and whether invasive species, long associated with artificial structures in flow‐restricted habitats, have adapted to these conditions remains unclear. We measured water flow and oxygen availability in marinas and piers at the scales relevant to sessile marine invertebrates (mm). We then measured the capacity of invasive and native marine invertebrates to maintain metabolic rates under decreasing levels of oxygen using standard laboratory assays. We found that marinas reduce water flow relative to piers, and that local oxygen levels can be zero in low flow conditions. We also found that for species with erect growth forms, invasive species can tolerate much lower levels of oxygen relative to native species. Integrating the field and laboratory data showed that up to 30% of available microhabitats within low flow environments are physiologically stressful for native species, while only 18% of the same habitat is physiologically stressful for invasive species. These results suggest that invasive species have adapted to low oxygen habitats associated with manmade habitats, and artificial structures may be creating niche opportunities for invasive species.     

Variability at different spatial scales of a coralligenous assemblage at Giannutri Island (Tuscan Archipelago,northwest Mediterranean)

This study was carried out on the rocky cliffs of Giannutri Island (Tyrrhenian Sea, Italy) to test the hypothesis that coralligenous assemblages are consistent within the bathymetric range considered (25–35 m depth) over three different spatial scales (1000 m, 100 m and 10 m). A multi-factorial sampling design was used to assess patterns of vertical distribution in the studied area. Data on the percent cover of algae and invertebrates were collected at three depths (25, 30 and 35 m) using a photographic method, and percentage cover was obtained using a visual method. Analysis of the results using ANOVA indicated that the distribution and abundance of algae and some invertebrates of the sublittoral assemblages are clearly heterogeneous. Algae, sponges and bryozoans showed significant variability in distribution and abundance at different depths, but this variability was not consistent amongst transects. Ascidians did not show any variability, while the abundance of anthozoans differed significantly amongst transects. We concluded that heterogeneity in the distribution and abundance of the taxa analysed is related to the smallest spatial scale investigated (10's of m). Some of the possible causes of the observed variability are discussed.