Ten polymorphic microsatellite DNA loci for paternity and population genetics analysis in the fen raft spider (Dolomedes plantarius)

Ten polymorphic di‐ and trinucleotide microsatellite loci were developed in the fen raft spider Dolomedes plantarius from a partial phagemid genomic library enriched for microsatellite inserts. The expected heterozygosity at these loci ranges from 0.62 to 0.9, with the observed allele numbers varying from four to 15 in the 22 individuals tested. Average paternity exclusion probabilities ranged between 0.290 and 0.686. In combination, the 10 polymorphic loci elicit an exclusion probability of 0.999. The high level of polymorphism of these microsatellite loci makes them ideal genetic markers for paternity and population genetics analysis in this endangered species.     

Frequent amplification of PTP1B is associated with poor survival of gastric cancer patients

The protein tyrosine phosphatase 1B (PTP1B), a non-transmembrane protein tyrosine phosphatase, has been implicated in gastric pathogenesis. Several lines of recent evidences have shown that PTP1B is highly amplified in breast and prostate cancers. The aim of this study was to investigate PTP1B amplification in gastric cancer and its association with poor prognosis of gastric cancer patients, and further determine the role of PTP1B in gastric tumorigenesis. Our data demonstrated that PTP1B was significantly up-regulated in gastric cancer tissues as compared with matched normal gastric tissues by using quantitative RT-PCR (qRT-PCR) assay. In addition, copy number analysis showed that PTP1B was amplified in 68/131 (51.9%) gastric cancer cases, whereas no amplification was found in the control subjects. Notably, PTP1B amplification was positively associated with its protein expression, and was significantly related to poor survival of gastric cancer patients. Knocking down PTP1B expression in gastric cancer cells significantly inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrested and apoptosis. Mechanically, PTP1B promotes gastric cancer cell proliferation, survival and invasiveness through modulating Src-related signaling pathways, such as Src/Ras/MAPK and Src/phosphatidylinositol-3-kinase (PI3K)/Akt pathways. Collectively, our data demonstrated frequent overexpression and amplification PTP1B in gastric cancer, and further determined the oncogenic role of PTP1B in gastric carcinogenesis. Importantly, PTP1B amplification predicts poor survival of gastric cancer patients.     

Decomposition and Peat Accumulation in Rich Fens of Boreal Alberta, Canada

Fens are important components of Canada’s western boreal forests, occupying about 63% of the total peatland area and storing about 65% of the peatland carbon. Rich fens, dominated by true moss-dominated ground layers, make up more than half of the fens in the region. We studied organic matter accumulation in three rich fens that represent the diversity in structural types. We used in situ decomposition socks, a new method that examines actual decomposition throughout the upper peat profile over an extended period of time. We coupled our carbon loss data with macrofossil analyses and dated peat profiles using ²¹⁰Pb. Across the three rich fens and in the top 39 cm of the peat column, dry mass increases on average 3.1 times. From our dry mass loss measurements, we calculate that annual mass loss from the top 39 cm varies from 0.52 to 1.08 kg m². Vertical accumulation during the past 50 years has varied from 16 to 32 cm and during these 50 years, organic matter accumulation has averaged 174 g m⁻² y⁻¹ compared to 527 g m² y⁻¹ dry mass loss, with additional mass losses of 306 g m² y⁻¹ from peat between 50 and 150 years of age. Organic matter accumulation from our rich fens compares well with literature values from boreal bogs, whereas peat bulk densities increase about three times within the uppermost 40 cm, much more than in bogs. Hence, rich fens accumulate peat not because the plant material is especially hard to decompose, is acidic, or has the catotelm especially close to the surface, but because dense, rapidly produced inputs outweigh the relatively rapid decomposition process of the upper peat column. Author Contributions: DHV conceived study; KS, KW, SF, & DHV performed research; DHV, KW analyzed data; DHV, KW contributed new methods; DHV, KW wrote the paper.     

Winter Burning and the Reduction of Cornus sericea in Sedge Meadows in Southern Wisconsin

To control shrubs, which are increasing in dominance in wetlands worldwide, winter burning may be an important tool, especially from the perspective of minimizing urban hazards. The goal of this project was to determine if winter burning was successful in reducing the dominance (mean percentage cover and maximum height) of Cornus sericea in sedge meadows in southern Wisconsin, where shrubs proliferated after cattle were excluded. Experimental burn and control plots were set up within sedge meadows, including an ungrazed “reference” site that had been little, if ever, grazed and a “historically grazed” site, a recovery site that had not been grazed by cattle since 1973. None of the dominant species including C. sericea was significantly affected by burning for either mean percentage cover or maximum height (analysis of variance: no burning × species interaction). Both mean percentage cover and maximum height were only weakly related to burning (28.1 and 14.3% of the variability contributed to the cumulative percentage of the coefficient of determination, respectively) at both sites based on non‐metric multidimensional scaling analysis. Although species richness increased in burned plots in 1999 and 2000, no differences were apparent between pre‐burned and unburned plots in 1997 and unburned plots in 1999 and 2000 (analysis of variance: year × burning interaction). After burning in the ungrazed site, herbaceous species appeared that had not been detected for decades, including Chelone glabra and Lathyrus palustris. Exotic species were present in both the ungrazed reference and recovery site. Although winter burning treatments did not reduce the dominance of woody shrub species in the site recovering from cattle grazing, burning was useful in stimulating the maintenance of species richness in the ungrazed sedge meadow.     

The relation between vegetation and soil chemistry gradients in a ground water discharge fen

Abstract. The soil chemistry of a headwater valley fen is influenced by local ground water discharge that supplies base cations and alkalinity to the fen. An irrigation canal just upward of the fen is the source of this alkalinity. The ecological consequences of this artificial system are studied both on the soil and vegetation level. Rich-fen species of the alliance Caricion davallianae are connected to soil water alkalinity and soil base status. They depend directly on the alkaline ground water discharge. In addition, the local input of this water causes a gradient-rich pattern from poor to rich fen, and it is therefore concluded that it is responsible for the presence of intermediate fen vegetation too. High nutrient levels in the irrigation water have not influenced the fen until now. This case study illustrates the possibility for rich fen restoration after acidification. Irrigation with alkaline water is efficient if excess nutrients can be removed.     

Diatom assemblages along a former intertidal gradient: A palaeoecological study of a subboreal clay layer (Western coastal plain,Belgium)

Lateral and vertical variations in diatom taphocoenoses were studied in a clayey intercalation in the upper peat bed at Booitshoeke (western coastal plain, Belgium). The palaeoecological evolution, linked to sedimentary facies changes along the ecotone from fen to tidal flat, apparently involved two successive periods of increased local tidal activity. This result could be inferred from a weakly developed salt-marsh horizon within the clay, traceable by diatom analysis over a distance of a few hundred meters. Although influenced by taphonomic processes, the composition of the fossil assemblages appeared to reflect the relative position of the palaeoenvironment along the tidal gradient fairly accurately. Taphonomic groups of taxa could be distinguished, characterizing respectively the transition from fen to salt-marsh, the high salt-marsh, the low salt-marsh and high mud-flat, and the more polyhaline mud-flat. Sediments of drier salt-marsh conditions showed a very poor taphocoenosis, of mainly allochthonous origin, dominated by marine tychoplanktonic species with durable frustules. Some possible causes for the slight increase in marine activity during the mid-Subboreal, which resulted in the formation of the deposits considered here, are discussed.     

Genetic structure and AFLP variation of remnant populations in the rare plant Pedicularis palustris (Scrophulariaceae) and its relation to population size and reproductive components

We investigated plant reproduction in relation to genetic structure, population size, and habitat quality in 13 populations of the rare biennial plant Pedicularis palustris with 3-28500 flowering individuals. We used AFLP (amplified fragment length polymorphism) profiles to analyze genetic similarities among 129 individuals (3-15 per population). In a cluster analysis of genetic similarities most individuals (67%) were arranged in population-specific clusters. Analysis of molecular variance indicated significant genetic differentiation among populations and among and within subpopulations (P < 0.001). Gene flow (N(e) m) was low (0.298). On average, plants produced 55 capsules, 17 seeds per fruit, and 42 seedlings in the following growing season. The number of seeds per capsule was independent of population size and of genetic variability. In contrast, the number of capsules per plant (P < 0.05) and the number of seedlings per plant (P < 0.05) were positively correlated with population size. The relation between population size and the number of seeds per plant was not significant (P = 0.075). The number of capsules and of seeds and seedlings per plant (P < 0.01) were positively correlated with genetic variability. Genetic variability was independent of actual population size, suggesting that historical population processes have to be taken into account, too. Stepwise multiple regressions revealed additional significant relationships of habitat parameters (soil pH, C:N ratio), vegetation composition, and standing crop on reproductive components. We conclude that populations of P. palustris are genetically isolated and that reproductive success most likely is influenced by population size, genetic variability, and habitat quality. Management strategies such as moderate grazing, mowing, and artificial gene flow should endeavor to increase population size as well as genetic variation.     

Climate warming alters effects of management on population viability of threatened species: results from a 30‐year experimental study on a rare orchid

Climate change is expected to influence the viability of populations both directly and indirectly, via species interactions. The effects of large‐scale climate change are also likely to interact with local habitat conditions. Management actions designed to preserve threatened species therefore need to adapt both to the prevailing climate and local conditions. Yet, few studies have separated the direct and indirect effects of climatic variables on the viability of local populations and discussed the implications for optimal management. We used 30 years of demographic data to estimate the simultaneous effects of management practice and among‐year variation in four climatic variables on individual survival, growth and fecundity in one coastal and one inland population of the perennial orchid Dactylorhiza lapponica in Norway. Current management, mowing, is expected to reduce competitive interactions. Statistical models of how climate and management practice influenced vital rates were incorporated into matrix population models to quantify effects on population growth rate. Effects of climate differed between mown and control plots in both populations. In particular, population growth rate increased more strongly with summer temperature in mown plots than in control plots. Population growth rate declined with spring temperature in the inland population, and with precipitation in the coastal population, and the decline was stronger in control plots in both populations. These results illustrate that both direct and indirect effects of climate change are important for population viability and that net effects depend both on local abiotic conditions and on biotic conditions in terms of management practice and intensity of competition. The results also show that effects of management practices influencing competitive interactions can strongly depend on climatic factors. We conclude that interactions between climate and management should be considered to reliably predict future population viability and optimize conservation actions.