Ecological genetics of Norwegian Daphnia I. Genetic differentiation between pigmented and unpigmented alpine pond populations

The genetic composition of seven Daphnia populations was studied by starch gel electrophoresis: one lowland lake population and six populations inhabiting mountain ponds. Four alpine populations consisted of darkly pigmented animals, two alpine ponds and the lake were populated by non-pigmented Daphnia. The population of each pond contained the same genotype; only two ponds contained the same dominating genotype. The genetic distance between pigmented and transparent Daphnia was of a magnitude commonly found in comparisons between different species, whereas genetic distances found within the groups of pigmented or non-pigmented Daphnia were of a magnitude consistent with the assumption of local populations of one species. This dichotomy suggests that melanin pigmentation did not evolve independently in several lineages, but was acquired by a common ancestor of all pigmented Daphnia studied. The genetic variability was much higher in the lake population than in any of the pond populations

Molecular biogeography of clonal lineages in a high-Arctic apomictic Daphnia complex

An electrophoretic survey of 81 populations of arctic Daphnia pulex from around the Svalbard archipelago revealed the presence of 49 unique allozyme clones (N = 3357). Two closely related clones accounted for 66% of the total sample, and were widespread across the archipelago. Restriction fragment length polymorphisms (RFLPs) of a 2.1-kb fragment of mtDNA (NADH-4 and NADH-5 subunits), amplified using the polymerase chain reaction (PCR), revealed the presence of eight mtDNA haplotypes. One haplotype was particularly widespread, and the two most abundant allozyme clones shared this haplotype. Nonrandom distribution patterns of clones were observed, and are most likely the result of historical events (i.e. founder effects) related to the past glacial history of the archipelago. The data are discussed with reference to past glaciation events, and attempts are made to discern the colonization history of this apomictic comple

Molecular characterization of clonal population structure and biogeography of arctic apomictic Daphnia from Greenland and Iceland

As part of a continuing international project to characterize the population genetic (clonal) structure of arctic members of the Daphnia pulex complex, 34 populations from western Iceland (N = 1373), and 76 populations from western Greenland (N = 2917), were surveyed for allozymic variation at six polymorphic enzyme loci. Mean clonal richness (+/-SE) was 1.91+/-0.19 and 1.50+/-0.12 for Iceland and Greenland populations, respectively. Mean clonal diversity (+/-1 SE) was 1.20+/-0.07 and 1.13+/-0.04 for Iceland and Greenland populations, respectively. Four widely distributed clones constituted 92.2% of the total animals surveyed from Iceland, while three locally abundant clones constituted 80.1% of the total animals collected primarily from Disko Island, western Greenland. Selected populations were screened for mitochondrial (mt)DNA variation using PCR-based RFLP analysis of a 2100 bp fragment containing part of the ND4 and ND5 genes. One mtDNA haplotype was very widespread in both western Greenland and western Iceland, although, a number of mutational derivatives were also detected. These data indicate the potential for long-distance dispersal of mtDNA lineages, of the order of hundreds or thousands of kilometers across the arctic. Phylogenetic analysis of the sequence of a 254 base pair (bp) fragment of the control region of the mtDNA molecule revealed two major clades one of which consisted solely of non-melanic lineages, and the other of which consisted almost exclusively of melanic lineages (i.e. one non-melanic lineage also clustered in this clade). Sequence divergence between the two clades averaged 7.3%. both mitochondrial analyses did not reveal any distinct intraregional clustering of lineages. We discuss our results in reference to previous molecular work done on this arctic Daphnia complex, and we attempt to infer phylogeographic patterning based on geological/glaciological historical events in this region of the arcti

Molecular characterization of clonal population structure and biogeography of arctic apomictic Daphnia from Greenland and Iceland

As part of a continuing international project to characterize the population genetic (clonal) structure of arctic members of the Daphnia pulex complex, 34 populations from western Iceland (N = 1373), and 76 populations from western Greenland (N = 2917), were surveyed for allozymic variation at six polymorphic enzyme loci. Mean clonal richness (+/-SE) was 1.91+/-0.19 and 1.50+/-0.12 for Iceland and Greenland populations, respectively. Mean clonal diversity (+/-1 SE) was 1.20+/-0.07 and 1.13+/-0.04 for Iceland and Greenland populations, respectively. Four widely distributed clones constituted 92.2% of the total animals surveyed from Iceland, while three locally abundant clones constituted 80.1% of the total animals collected primarily from Disko Island, western Greenland. Selected populations were screened for mitochondrial (mt)DNA variation using PCR-based RFLP analysis of a 2100 bp fragment containing part of the ND4 and ND5 genes. One mtDNA haplotype was very widespread in both western Greenland and western Iceland, although, a number of mutational derivatives were also detected. These data indicate the potential for long-distance dispersal of mtDNA lineages, of the order of hundreds or thousands of kilometers across the arctic. Phylogenetic analysis of the sequence of a 254 base pair (bp) fragment of the control region of the mtDNA molecule revealed two major clades one of which consisted solely of non-melanic lineages, and the other of which consisted almost exclusively of melanic lineages (i.e. one non-melanic lineage also clustered in this clade). Sequence divergence between the two clades averaged 7.3%. both mitochondrial analyses did not reveal any distinct intraregional clustering of lineages. We discuss our results in reference to previous molecular work done on this arctic Daphnia complex, and we attempt to infer phylogeographic patterning based on geological/glaciological historical events in this region of the arcti

Defining ecological and chemical reference conditions and restoration targets for nine European lakes

This paper aims to determine the ecological and chemical reference conditions (~1800–1850 AD) and degree of floristic change at nine enriched lakes, covering a range of types across Europe, using fossil diatom assemblages in dated sediment cores and application of total phosphorus (TP) transfer functions. Additionally the study assesses the potential of analogue matching as a technique for identifying reference sites and for estimating reference TP concentrations for the study lakes using a training set of 347 European lakes and 719 diatom taxa. Oligotrophic, acidophilous to circumneutral taxa were predominant in the reference samples of several of the deep lakes, and benthic Fragilaria spp. dominated the reference samples of two high alkalinity shallow lakes. The degree of floristic change from the reference sample, assessed using the squared chord distance (SCD) dissimilarity coefficient, revealed that two sites had experienced slight change (Lago Maggiore, Felbrigg Lake), five experienced moderate change (Mjoesa, Loch Davan, Loch Leven, White Lough, Esthwaite Water), and two showed evidence of major change (Groby Pool, Piburger See). For three lakes, there were no analogues in the diatom dataset owing to the uniqueness and diversity of the diatom reference assemblages. For the remaining six sites the number of analogues ranged from 2 to 44. For two deep lakes most of the analogues seemed appropriate as they were of the same type and had low TP concentrations. However, for two other deep lakes and two shallow lakes some of the analogues differed markedly in their depth and alkalinity from the lake in question or had TP concentrations seemingly too high to represent reference conditions suggesting that the analogues may not be suitable as reference sites. For the deep lakes, similar reference TP values were calculated using the EDDI Combined TP transfer function and the analogue matching technique with concentrations typically <20 μg L−1. However, for the shallow lakes, the analogue matching method produced inferred values considerably higher than those of the transfer function. The wide ecological tolerances of many of the diatom taxa found in the reference samples most likely explain the selection of inappropriate analogue sites. In summary, the study demonstrates that palaeoecological techniques can play a valuable role in determining reference conditions and indicates that the analogue matching technique has the potential to be a useful tool for identifying appropriate reference sites for lakes impacted by eutrophication

History Teaches Us That Confronting Antibiotic Resistance Requires Stronger Global Collective Action

© 2015 American Society of Law, Medicine & Ethics, Inc. Antibiotic development and usage, and antibiotic resistance in particular, are today considered global concerns, simultaneously mandating local and global perspectives and actions. Yet such global considerations have not always been part of antibiotic policy formation, and those who attempt to formulate a globally coordinated response to antibiotic resistance will need to confront a history of heterogeneous, often uncoordinated, and at times conflicting reform efforts, whose legacies remain apparent today. Historical analysis permits us to highlight such entrenched trends and processes, helping to frame contemporary efforts to improve access, conservation and innovation.Peer Reviewe

Environment and biogeography drive aquatic plant and cladoceran species richness across Europe

1. The relative role of environmental and regional processes in determining patterns of biodiversity may vary across spatial scales. In inland aquatic communities, macrophytes and zooplankton have the potential to disperse over large spatial scales (hundreds of kilometres), but the role of environmental and regional processes in determining species richness (SR) at different spatial scales is poorly understood. 2. To assess the relative importance of environmental and regional processes acting on both regional (within-region) and continental (among-region) scales, we surveyed 139 waterbodies in five geographic regions (Spain, Italy, the Netherlands, Scotland and Norway) and in each region measured environmental variables, descriptors of connectivity and SR of two aquatic taxa, namely aquatic plants and cladocerans. 3. Analyses using boosted regression trees and generalised linear models, integrated with multiple imputation of missing data, indicated that both environmental and regional processes were related to local SR. 4. Total phosphorus was the main environmental correlate of SR, showing a unimodal relationship with both taxonomic groups. Conductivity and lake depth were also related to cladoceran SR, and Secchi depth was related to aquatic plant richness. 5. The SR of aquatic plants and cladocerans were significantly correlated, but this relationship was mainly indirect (i.e. determined by the effect of common environmental variables). 6. The limited role of connectivity and space (lack of spatial autocorrelation in model residuals) relative to environment suggests that dispersal limitation is not as important as the environment in explaining richness patterns for both groups within regions. However, region identity strongly influenced SR, which suggests an important effect of biogeographic factors (e.g. the level of endemicity; the number of unique species in each region) and/or dispersal limitation at the continental scale. 7. We conclude that environmental factors and biogeographic processes largely determine the patterns of local and regional SR in aquatic plants and zooplankton