Genetic diversity and differentiation of the Western Leopard Toad (Sclerophrys pantherina) based on mitochondrial and microsatellite markers

Intraspecific genetic diversity provides the basis for evolutionary change and is therefore considered the most fundamental level of biodiversity. Mitochondrial DNA (mtDNA) and microsatellite loci are the markers most typically used in population-level studies; however, their patterns of genetic variation are not always congruent. This can result in different interpretations of the data, which can impact on management decisions, especially for threatened species. Consequently, in this study, we developed and analysed novel microsatellite markers for the Endangered Western Leopard Toad (WLT), Sclerophrys pantherina, and compared the results to previously published mtDNA data to compare the level of genetic diversity between the two molecular markers. The microsatellite evidence showed signs of a past bottleneck, yet relatively high levels of genetic diversity and low genetic differentiation between two sampling sites. In contrast, the mtDNA revealed moderate to low levels of diversity between sampling sites, and strong genetic differentiation. An explanation for the conflicting patterns may be that the current genetic signature, as depicted by the microsatellite data, is not yet reflected in the mitochondrial dataset; and, as such the data are depicting a timeline for genetic variation within the WLT. Both markers revealed important information about the two sampling sites, which can help inform conservation management of the species

Paralytich shellfish poisoning in the abalone Haliotis midae on the westcoast of South Africa

In April 1999, monitoring on two West Coast abalone farms provided evidence of the presence of Paralytic Shellfish Poisoning (PSP) toxins in the cultured abalone Haliotis midae. Subsequent analysis of wild animals collected from the West Coast also revealed the accumulation of PSP toxins in these gastropods. The toxicity of individual animals as measured by the AOAC mouse bioassay showed considerable variation, ranging from below the assay detection limit to a maximum of 1609 µg STXeq 100 g-1. Initial observations found PSP toxins in abalone to be coincident with blooms of Alexandrium catenella indicating that this dinoflagellate was the probable cause of abalone toxicity. Subsequent detection by receptor binding assay, of toxicity in abalone on the South Coast, an area considered free of A. catenella blooms, casts some doubt as to the source of the toxins. The toxin composition in the abalone as determined by HPLC was dominated by STX, and differed significantly from the toxin profile of A. catenella and the co-occurring mussel, Mytilus galloprovincialis. Either these findings indicated a high capacity for biotransformation of PSP toxins by abalone or that A. catenella was not the source of the toxin. Investigation of the anatomical distribution of toxins revealed that they were not evenly distributed throughout the abalone tissues, but appeared to concentrate in outer layer tissue. The muscular foot made a disproportionately low contribution to the total toxin content of the mollusc, whereas the epipodial fringe, although comprising a small proportion of the abalone total weight, contributed substantially to the total toxin content. The epipodial fringe is typically included with the muscular foot as that part of the animal marketed for human consumption. The negative impacts of PSP contamination on abalone spawning and larval survival are presented and the findings of this study are compared to observations of PSP toxins in the abalone Haliotis tuberculata on the Galician coast. The inability of abalone to detoxify or depurate accumulated PSP toxins below the regulatory level threatens the future of the established abalone fishery and the newly developed aquaculture operations on the West Coast of South Africa.Versión del editor1,041

Extraction of domoic acid from seawater and urine using a resin based on 2-(trifluoromethyl)acrylic acid.

A new solid-phase extraction (SPE) matrix with high affinity for the neurotoxin domoic acid (DA) was designed and tested. A computational modelling study led to the selection of 2-(trifluoromethyl)acrylic acid (TFMAA) as a functional monomer capable of imparting affinity towards domoic acid. Polymeric adsorbents containing TFMAA were synthesised and tested in high ionic strength solutions such as urine and seawater. The TFMAA-based polymers demonstrated excellent performance in solid-phase extraction of domoic acid, retaining the toxin while salts and other interfering compounds such as aspartic and glutamic acids were removed by washing and selective elution. It was shown that the TFMAA-based polymer provided the level of purification of domoic acid from urine and seawater acceptable for its quantification by high performance liquid chromatography\u2013mass spectrometry (HPLC\u2013MS) and enzyme-linked immunosorbent assay (ELISA) without any additional pre-concentration and purification step

Global solutions to regional problems: Collecting global expertise to address the problem of harmful cyanobacterial blooms. A Lake Erie case study

In early August 2014, the municipality of Toledo, OH (USA) issued a ‘do not drink’ advisory on their water supply directly affecting over 400,000 residential customers and hundreds of businesses (Wilson, 2014). This order was attributable to levels of microcystin, a potent liver toxin, which rose to 2.5 μg L−1 in finished drinking water. The Toledo crisis afforded an opportunity to bring together scientists from around the world to share ideas regarding factors that contribute to bloom formation and toxigenicity, bloom and toxin detection as well as prevention and remediation of bloom events. These discussions took place at an NSF- and NOAA-sponsored workshop at Bowling Green State University on April 13 and 14, 2015. In all, more than 100 attendees from six countries and 15 US states gathered together to share their perspectives. The purpose of this review is to present the consensus summary of these issues that emerged from discussions at the Workshop. As additional reports in this special issue provide detailed reviews on many major CHAB species, this paper focuses on the general themes common to all blooms, such as bloom detection, modeling, nutrient loading, and strategies to reduce nutrients