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Microorganisms are spectacularly diverse phylogenetically, but available estimates of their species richness are vague and problematic. For example, for comparable environments, the estimated numbers of species range from a few dozen or hundreds to tens of thousands and even half a million. Such estimates provide no baseline information on either local or global microbial species richness. We argue that this uncertainty is due in large part to the way statistical tools are used, if not indeed misused, in biodiversity research. Here we develop a powerful synthetic statistical approach to quantify biodiversity. It provides statistically sound estimates of microbial richness at any level of taxonomic hierarchy. We apply this approach to a large original 16S rRNA dataset on marine bacterial diversity and show that the number of bacterial species in a sample from marine sediments is (2.4 ± 0.5 SE) × 10³. We argue that our methodology provides estimates of microbial richness that are reliable and general, have biologically meaningful SEs, and meet other fundamental statistical standards. This approach can be an essential tool in biodiversity research, and the estimates of microbial richness presented here can serve as a baseline in microbial diversity studies. [ABSTRACT FROM AUTHOR]

Analysis of uncompensated solution resistance for electrodes with spherical-cap geometry. Measurements of a test reaction by cyclic voltammetry. Resistance effects at more than one concentration; Analysis by digital simulation; Determination of the standard heterogeneous electron-transfer rate constant.

Monoecious and dioecious forms of the submerged aquatic plant hydrilla, Hydrilla verticillata (Hydrocharitaceae) are invasive weeds in the United States. Monoecious hydrilla is expanding northward and the existing biological control agents are not controlling it effectively. Results of fine-scale genetic identification of plants and herbivores matched the invasive US monoecious hydrilla genotype with a leaf-mining fly, Hydrellia sp. in their native range in the Republic of Korea. This fly was imported into quarantine in Australia to conduct preliminary evaluations of its biology, life-history and host range; a pre-screening before considering its importation into US quarantine for complete assessment as a potential biological control agent. The fly completed its development on two non-target test plant species, Elodea canadensis and Potamogeton crispus, the former being native to North America. It was recommended that no further consideration be given to Hydrellia sp. as a biological control agent of monoecious hydrilla. Other Hydrellia species from the Republic of Korea and China found on monoecious hydrilla should instead be evaluated. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to evaluate the antioxidant and neuroprotective activities in the aerial parts of seven Eragrostis species (Poaceae) and to find antioxidant or neuroprotective compounds from the most active species. The total phenolic content (TPC), total flavonoid content (TFC), 1,1-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH RSA), total antioxidant capacity (TAC), and neuroprotective activity against amyloid beta peptide induced toxicity in PC12 cells were measured in the methanol extracts of the aerial parts of E. ferruginea, E. cilianensis, E. minor, E. multicaulis, E. pilosa, E. japonica, and E. curvula collected from June to August 2013. All species showed antioxidant or neuroprotective activities and, among them, E. japonica was the most active species to isolate antioxidant or neuroprotective compounds, because it was found to show both the highest TPC (10.63 ± 0.31 mg/g) and TFC (2.83 ± 0.06 mg/g) values, as well as TAC (11.34 ± 0.80 mg/g) and DPPH RSA (47.07 ± 2.81 μg/mL), with the second-highest neuroprotective value (23.0 μg/mL). Three known compounds were isolated from E. japonica by the bioassay guided approach and these were identified as isoorientin, isovitexin, and caffeic acid that have antioxidant and neuroprotective activities. [ABSTRACT FROM AUTHOR]

• We conducted surveys across China and South Korea for natural enemies of hydrilla. • DNA barcoding identified 14 chironomid midge species. • Four distinct Hydrellia (Ephydridae) clades were identified. • Our results help clarify the species status of the collected material. • They also suggest hypotheses for further testing through additional structured sampling and screening. Biological control is considered the best management option against the aquatic weed Hydrilla verticillata , one of the most damaging invasive plants in the United States. The search for natural enemies is ongoing. Larval flies from two families (Ephydridae and Chironomidae) were collected feeding on H. verticillata during recent surveys across China and Korea (the possible origin of both the monoecious and dioecious forms of this weed found in the United States). DNA barcoding was used to provide initial identifications, using the Barcode of Life database. In addition, we assessed the genetic structuring and geographic distribution of each provisionally identified species. Four distinct Hydrellia (Ephydridae) clades were identified. The species identity of these clades could not be confirmed, although two form part of the Hydrellia pakistanae species group. Significant genetic structuring was observed within the most widespread clade , suggesting it may comprise several species, although further investigation is required. Fourteen distinct chironomid clades were identified, nine of which correspond to previously described species. Genetic diversity within the chironomid species was low, even across a broad spatial scale, though some genetic structuring was observed in Cricotopus sylvestris. The results of this study provide direction for additional sampling of H. verticillata across China and Korea. Specifically, we recommend further surveys in Zhouzhuang (China), Yeonpori, Yangsancheon, and Deokeuwonri (all Korea). These surveys should be complemented with structured population genetics screening of both plant and insect material; this will help resolve the species status and host associations of the discrete mitochondrial lineages identified in this study. [ABSTRACT FROM AUTHOR]