Urban forest values in Canada: Views of citizens in Calgary and Halifax

A significant component of the urban ecosystem is the urban forest. It is also the quintessential meeting point of culture and nature, so it is critical to incorporate values-based approaches to managing them. The values that really count are those of urban citizens. A novel qualitative method was used to determine what qualities of the urban forest are valued by citizens of Calgary, Alberta, and Halifax, Nova Scotia, Canada. These values were compared with those reported in the literature to reveal that citizens value the urban forests mostly for their non-material benefits. Specifically, urban forests contribute to human emotional, intellectual, and moral fulfilment.     

Unusual Ether Lipids and Branched Chain Fatty Acids in Sea Cucumber (Cucumaria frondosa) Viscera and Their Seasonal Variation

The sea cucumber, Cucumaria frondosa, is harvested primarily for its muscular bands and body wall. Development of a nutraceutical product based on lipid recovered from its viscera would give commercial value to the entire organism; however, such development requires knowledge of the lipid and fatty acid (FA) profiles of the viscera. Here, we describe the lipid and FA composition of viscera recovered from C. frondosa harvested in coastal waters in the northwest Atlantic, taking into account variation due to harvest season. We found highest lipid content at ~29% in winter, with diacylglyceryl ethers (DAGE) comprising ~55% of the total lipid mass and triacylglycerols (TAG), phospholipids (PL) and monoacylglycerol ethers (MAGE) at 5–25% each. The branched chain FA, 12-methyltetradecanoic acid (12-MTA), represented 42% of total FA mass in DAGE. In summer, lipid content was lower at 24% and TAG was the dominate lipid, with proportions more than double that found in winter (45% vs. 20%); DAGE in summer dropped to ~30% of total lipids. In TAG, 12-MTA was much lower than found in DAGE in winter, at only 10% but eicosapentaenoic acid (EPA) content was ~20%, which brought the total EPA% to 28% of total FA—the highest among all three seasons. There was little effect of season on MAGE or PL proportions. These data can help harvesters maximize catch efforts in terms of lipid yield and profile.     

Multiplication and rate of reinfection of virus-free potatoes in Prince Edward Island

When five varieties of virus-free potatoes were introduced and multiplied for three years at an elite seed farm in Prince Edward Island where virus-infected potatoes were also grown, approximatly 10% of each variety became infected with both potato virs S (PVS) and potato virus X (PVX). However, when eight varieties of similar stocks were multiplied for 2 years at private farms in the absence of virus-infected potatoes, all remained free from PVX. Four of the varieties also remained free from PVS and four became infected with amounts of less than 5%. In other tests on these stocks, no potato virus Y (PVY) was detected. Post harvest tuber testing onNicotiana debneyi Domin. was found to be more reliable in detecting recent infections of PVS than foliage tests done during the growing season. This was so whether the foliage tests were done on the indicator plant, serologically or doubly-tested by both methods.     

Biomimetic extraction of Bacillus thuringiensis insecticidal crystal proteins from soil based on invertebrate gut fluid chemistry

Quantitative monitoring of Bacillus thuringiensis (Bt) insecticidal crystal proteins in soil has been hampered by the lack of efficient extraction/detection methods. A novel approach for simple and effective Bt protein extraction was explored by evaluating extraction solutions from invertebrate gut fluids. Marine worm gut fluids were identified as promising for extracting Bt protein from soil. An artificial gut fluid based on these marine worm gut fluids was developed using commercially available chemicals and was evaluated for its ability to extract Bt proteins from soil. On the basis of experiments with Cry1 proteins, the artificial gut fluid in combination with ELISA was highly effective for protein extraction and analysis in a variety of soil types and was well-correlated with bioassay results. Coupling of immunoassay with this extraction method provides, for the first time, an efficient, accurate, and quantitative assay for routine measurement of Bt protein residues in soil.     

A cross-seasonal comparison of active and total bacterial community composition in Arctic tundra soil using bromodeoxyuridine labeling

Arctic soil microorganisms remain active at ecologically relevant rates in frozen soils. We used bromodeoxyuridine (BrdU) labeling and terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA gene amplicons to examine active bacterial communities in two Alaskan tundra soils collected in summer and winter of 2005. Active community T-RFLP profiles were compared to total community profiles to determine if active bacteria were a subset of the total community. In shrub soils, active bacteria communities differed in composition between summer and winter, and winter-active bacterial taxa were not detected in the total community, suggesting that they are likely rare within the overall community. In contrast, tussock tundra soil contained more bacterial taxa that were active in both summer and winter and also represented a large portion of the total community. Using in silico digest of a sequence library from this site, we attempted to identify the dominant organisms in our samples. Our previous research suggested that the total microbial community was stable throughout the year, but this new study suggests that the active community is more dynamic seasonally. In general, only a subset of the total community was growing at a given time. This temporal niche partitioning may contribute to the high diversity of microbial communities in soils. Understanding which taxa contribute to microbial function under different conditions is the next frontier in microbial ecology and linking composition to biogeochemical cycling.     

Structure of a eukaryotic CLC transporter defines an intermediate state in the transport cycle

CLC proteins transport chloride (Cl(-)) ions across cell membranes to control the electrical potential of muscle cells, transfer electrolytes across epithelia, and control the pH and electrolyte composition of intracellular organelles. Some members of this protein family are Cl(-) ion channels, whereas others are secondary active transporters that exchange Cl(-) ions and protons (H(+)) with a 2:1 stoichiometry. We have determined the structure of a eukaryotic CLC transporter at 3.5 angstrom resolution. Cytoplasmic cystathionine beta-synthase (CBS) domains are strategically positioned to regulate the ion-transport pathway, and many disease-causing mutations in human CLCs reside on the CBS-transmembrane interface. Comparison with prokaryotic CLC shows that a gating glutamate residue changes conformation and suggests a basis for 2:1 Cl(-)/H(+) exchange and a simple mechanistic connection between CLC channels and transporters.