Connected by sea, disconnected by tuna? Challenges to regionalism in the Southwest Indian Ocean

Madagascar, Mauritius and Seychelles are at the center of industrial tuna extraction in the Southwest Indian Ocean (SWIO). In this paper, we show that, while a discourse of regionalism between the three islands is prominent, the possibilities of regionalism face deep challenges in relation to the tuna industry. This is due to three factors. First, local perceptions, especially amongst those working in and on the tuna industry, are in disconnection with an ‘Indianoceania’ vision. Second, the geopolitics between coastal states and distant water fishing nations create various entanglements including through fishing access revenue and foreign aid. Finally, the materiality of tuna can at times create competition as countries seek to individually maximize benefits from the industry. We argue that the active reinforcement of regional identity and collaboration around this resource is necessary to sustain local benefits into the future

Mathematical model approach to understand the ecological effect under chronic irradiation

Although aim of the environmental protection is conservation of ecosystem, there are only a few studies focusing on the effect of radiation on ecosystem. To understand the ecological effect of irradiation, microbial ecosystem, “microcosm”, which contains minimum components of ecosystem such as producer, consumer and decomposer, is useful because the natural ecosystem is too complex. The microcosm consists of three species, i.e. Euglena (producer), Tetrahymena (consumer), and E. coli (decomposer). The mathematical model and computer simulation model were also developed to understand the mechanism of ecological interaction using the results of acute exposure experiments of the microcosm, and we predicted Tetrahymena, which is the most radio-resistant among the constituent species, would be most sensitive in the chronically irradiated microcosm as a result of an indirect effect due to population decrease in E. coli. Recently we started chronic exposure experiments. The microcosms were irradiated with γ-rays at dose rate of 1.2Gy/day, 5Gy/day, 10Gy/day and 23Gy/day. From preliminary results, we found that the prediction from the models was different from the experimental results. Therefore, in this study, we improved our mathematical model and discuss the difference between the model and experiments

Эквидозиметрия повреждающих факторов на уровне популяций и сообществ водных организмов

Предложен новый экологический инструмент для сравнения равных эффектов различных факторов на уровне популяций и сообществ в качестве нового подхода - эквидозиметрии эффектов излучений (ионизирующих и ультрафиолетовых), ацидификации и металлов, а также любых других повреждающих воздействий.A principally new ecological tool is proposed for comparing equivalent effects of very different factors at the levels of populations and communities as the new approach - equidosimetry of effects by radiations (ionizing and ultra-violet), acidification and metals as well as any other deleterious impacts

Derivation of regional hazardous doses for amphibians acutely exposed to ionising radiation

Estimation of 50% lethal doses from nuclear DNA contents and subsequent species sensitivity distribution analysis was performed to derive regional 5% hazardous doses (HD5) for major orders Anura (e.g., frogs) and Caudata (e.g., salamanders) of amphibians inhabiting Japan, Australia, France, Czech Republic, Canada and some US states, where nuclear power plants or uranium mines are located. The HD5 values ranged from 3.0 to 7.7 Gy for the Anura inhabiting there while they ranged from 2.9 to 4.6 Gy for the Caudata. Comparison of these results with the worldwide HD5s (5.3 Gy for the Anura and 3.3 Gy for the Caudata) suggests that benchmark values for the Asian and Oceanic Anura and the European Caudata can be set at higher doses than the global values. Regional differences should be, therefore, considered when benchmark values are derived for some taxonomic groups

In vivo and in vitro characterization of the secA gene product of Bacillus subtilis.

The putative amino acid sequence from the wild-type Bacillus subtilis div+ gene, which complements the temperature-sensitive div-341 mutation, shares a 50% identity with the sequence from Escherichia coli secA (Y. Sadaie, H. Takamatsu, K. Nakamura, and K. Yamane, Gene 98:101-105, 1991). The B. subtilis div-341 mutant accumulated the precursor proteins of alpha-amylase and beta-lactamase at 45 degrees C as in the case of sec mutants of E. coli. The div-341 mutation is a transition mutation causing an amino acid replacement from Pro to Leu at residue 431 of the putative amino acid sequence. The B. subtilis div+ gene was overexpressed in E. coli under the control of the tac promoter, and its product was purified to homogeneity. The Div protein consists of a homodimer of 94-kDa subunits which possesses ATPase activity, and the first 7 amino acids of the putative Div protein were found to be subjected to limited proteolysis in the purified protein. The antiserum against B. subtilis Div weakly cross-reacted with E. coli SecA. On the other hand, B. subtilis Div could not replace E. coli SecA in an E. coli in vitro protein translocation system. The temperature-sensitive growth of the E. coli secA mutant could not be restored by the introduction of B. subtilis div+, which is expressed under the control of the spac-1 promoter, and vice versa. The B. subtilis div+ gene is the B. subtilis counterpart of E. coli secA, and we propose that the div+ gene be referred to as B. subtilis secA, although Div did not function in the protein translocation system of E. coli