Nitrate and nitrite ions were found to be successfully electroreduced at an in situ electrochemically pretreated copper electrode in acidic media, and their reduction peaks of a cyclic voltammogram were found at two distinct electrode potentials. Cyclic voltammetric experiments revealed a highly sensitive behavior of the pretreated copper electrode upon the electroreduction of nitrate and nitrite ions, and showed that a simultaneous voltammetric determination of the ions was achievable. Differential pulse voltammetry (DPV) was applied to the simultaneous determination. As a result, the detection limits were 0.26 and 0.17 μmol dm -3 for nitrate and nitrite ions, respectively. Simultaneous determinations for real samples (river water) were carried out by DPV at the pretreated copper electrode and spectrophotometry (the Griess method). The determination values obtained by both methods were in a good agreement with each other.

Reliable identification of species is important for protecting native ecosystems against the invasion of non-native species. DNA barcoding using molecular markers, such as the mitochondrial cytochrome oxidase subunit 1 (COI) gene, helps researchers distinguish species. In this study, we focused on introduced veronicellid slugs in the Ryukyu Islands and some greenhouses on mainland Japan. Some veronicellids are medium-to-high risk pest species for humans. Identifying veronicellid species by their external morphology is difficult and unreliable because there is substantial overlap between intraspecific variation and interspecific differentiation. Therefore, internal morphologies such as male genitalia have been the primary traits used to distinguish veronicellids. To identify introduced veronicellid slugs in Japan to the species level, we used morphological assessment of male genitalia and DNA barcoding of the standard COI gene fragment. We also conducted species-delimitation analyses based on the genetic data. The results showed that five evolutionarily significant units, corresponding to four nominal species inhabit the Ryukyu Islands, of which two species were also found in the greenhouses of mainland Japan, including the first record of Sarasinula plebeia in Japan. The presence of non-native slug species could increase the transmission of parasites in Japan.

12O40]3-), was formed through a reaction between a phosphate ion and molybdate ions in an acidic solution, and its electroreduction was examined in a flow electrolytic cell by TM voltammetry. Measured TM voltammograms showed two peaks corresponding to two successive two-electron reductions of the 12-molybdophosphate ion, and the peak intensities were proportional to the concentration of the phosphate ion. Because of the strong adsorption of 12-molybdophosphate ion onto the GRC electrode, a detection limit as low as 0.8 nmol dm -3 (S/N = 3) was achieved. The determination of phosphate ion in real samples (river water) was carried out by spectrophotometry (the molybdenumblue method) and TM voltammetry, and the determination values obtained by both methods were in a good agreement with each other. These results prove the possibility of TM voltammetry as an electroanalytical method.

To clarify the effect of niche conservatism on evolutionary history, we focused on freshwater snails, which have different ecological and phylogenetic properties from previously tested taxa. We conducted a phylogenetic analysis using 750 lymnaeid individuals from 357 sites of eleven Radix species. Then, we estimated the ancestral distribution using the geographic coordinates and colonization routes. In addition, a statistical test of the colonization distances in the latitudinal and longitudinal directions was performed. We also conducted ecological niche modeling for two widely distributed species using climatic data. Ancestral geographic reconstruction estimated the origin of the genus to be around the Indian subcontinental region and showed that latitudinal immigration distances were shorter than longitudinal immigration distances in the diversification process. Ecological niche models suggested that the current distribution was restricted by climate, with annual mean temperature and precipitation of the driest month as particularly strong factors. Niche conservatism to the climate can affect the diversification of freshwater snails.

Context: To analyze the nutritional and physicochemical parameters for the production of alkali-thermostable and cellulase free xylanase from bacteria. Objectives:The aim of this study was to isolation and identification and of alkali-thermostable and cellulase free xylanase producing bacteria from soil as well as optimization of process parameters for xylanase production. Materials and Methods:The bacterium Bacillus sp. was isolated from soil by serial dilution technique on xylan agar medium and identified by morphological and biochemical studies. The production of xylanase was carried out on xylan broth medium and xylanase activity was assayed by dinitrosalicylic acid (DNS) method. The effect of cultural parameters on the production of xylanase was determined by measuring the activity of xylanase. The effect of temperature and pH on the activity of partially purified xylanase as well as substrate specificity of xylanase were examined. Results:The maximum xylanase production (4000 U/L) by a Bacillus sp. was attained when the medium containing 0.5% wheat bran xylan and peptone at pH 8.0 and 50-55°C within 48-60 h. The partially purified xylanase was optimally active at pH 9.0 and 55°C. The xylanase showed high substrate activity towards wheat bran xylan but no activity towards cellulose, carboxymethyl cellulose and starch. Thus the enzyme was alkali-thermostable and cellulase free xylanase. Conclusion:The results obtained in this study suggest that the Bacillus sp. used is highly potential and useful for the production of cellulase free xylanase.