Low blue carbon storage in eelgrass (Zostera marina) meadows on the Pacific Coast of Canada.

Seagrass habitats provide important ecosystem services, including their ability to take up and store substantial amounts of organic carbon, known as 'blue carbon.' However, the paucity of geospatial and carbon storage information along the Pacific Coast of Canada hinders the inclusion of blue carbon storage data in conservation planning and policy development in coastal habitats. We assessed the carbon storage and accumulation rates in three eelgrass (Zostera marina) meadows in southern Clayoquot Sound on the Pacific Coast of British Columbia. The intertidal and subtidal portions of each meadow were mapped and sampled to estimate eelgrass density, biomass, and carbon, and sediment cores were analyzed to estimate sediment carbon storage and accumulation rates. Aboveground biomass measurements were consistent with estimates for Z. marina in other regions, with average aboveground carbon biomass estimates of 16.78 g C m-2 and 16.25 g C m-2 in the intertidal and subtidal areas, respectively. However, the estimated aboveground to belowground biomass ratio was an order of magnitude higher than for seagrass species in temperate/tropical areas, largely because belowground biomass was up to 10 times lower than for other Z. marina meadows, averaging 6.17 g C m-2 and 5.03 g C m-2 in the intertidal and subtidal zones, respectively. Sediment carbon concentrations did not exceed 1.30%Corg, and carbon accumulation rates ranged from 2.90-39.61 g Corg m-2 yr-1, decreasing with depth and averaging 10.8 ± 5.2 g Corg m-2 yr-1. While sediment carbon stocks were generally higher in the eelgrass meadows relative to non-vegetated reference sites, carbons stocks averaged 1343 ± 482 g Corg m-2, substantially less than global averages. These carbon results confirm that eelgrass does contribute to carbon storage in Clayoquot Sound but at lower rates than identified for more tropical seagrasses. By improving the quantification of site-specific carbon dynamics, eelgrass' role in climate change mitigation and conservation planning can be assessed.

A quinazoline-based HDAC inhibitor affects gene expression pathways involved in cholesterol biosynthesis and mevalonate in prostate cancer cells.

Chronic inflammation can lead to the development of cancers and resolution of inflammation is an ongoing challenge. Inflammation can result from dysregulation of the epigenome and a number of compounds that modify the epigenome are in clinical use. In this study the anti-inflammatory and anti-cancer effects of a quinazoline epigenetic-modulator compound were determined in prostate cancer cell lines using a non-hypothesis driven transcriptomics strategy utilising the Affymetrix PrimeView® Human Gene Expression microarray. GATHER and IPA software were used to analyse the data and to provide information on significantly modified biological processes, pathways and networks. A number of genes were differentially expressed in both PC3 and DU145 prostate cancer cell lines. The top canonical pathways that frequently arose across both cell lines at a number of time points included cholesterol biosynthesis and metabolism, and the mevalonate pathway. Targeting of sterol and mevalonate pathways may be a powerful anticancer approach.

Using a down-scaled bioclimate envelope model to determine long-term temporal connectivity of Garry oak (Quercus garryana) habitat in western North America: implications for protected area planning.

Under the Canadian Species at Risk Act (SARA), Garry oak (Quercus garryana) ecosystems are listed as "at-risk" and act as an umbrella for over one hundred species that are endangered to some degree. Understanding Garry oak responses to future climate scenarios at scales relevant to protected area managers is essential to effectively manage existing protected area networks and to guide the selection of temporally connected migration corridors, additional protected areas, and to maintain Garry oak populations over the next century. We present Garry oak distribution scenarios using two random forest models calibrated with down-scaled bioclimatic data for British Columbia, Washington, and Oregon based on 1961-1990 climate normals. The suitability models are calibrated using either both precipitation and temperature variables or using only temperature variables. We compare suitability predictions from four General Circulation Models (GCMs) and present CGCM2 model results under two emissions scenarios. For each GCM and emissions scenario we apply the two Garry oak suitability models and use the suitability models to determine the extent and temporal connectivity of climatically suitable Garry oak habitat within protected areas from 2010 to 2099. The suitability models indicate that while 164 km(2) of the total protected area network in the region (47,990 km(2)) contains recorded Garry oak presence, 1635 and 1680 km(2) of climatically suitable Garry oak habitat is currently under some form of protection. Of this suitable protected area, only between 6.6 and 7.3% will be "temporally connected" between 2010 and 2099 based on the CGCM2 model. These results highlight the need for public and private protected area organizations to work cooperatively in the development of corridors to maintain temporal connectivity in climatically suitable areas for the future of Garry oak ecosystems.

Simulations of the bis-penicillamine enkephalin in sodium chloride solution: a parameter study.

A simulation study of DPDPE in sodium chloride solution has been performed and compared with previous simulations using a different interaction potential for the ions. Both global thermodynamics as well as a characterization of association to DPDPE have been calculated. We show that the parameters used for the ions have a profound effect on the association to the peptide in 1M NaCl. The observed differences suggest that individual associations in these and previous simulations are sensitive to parameters.

Molecular recognition of Watson-Crick base-pair reversals in triple-helix formation: use of nonnatural oligonucleotide bases.

We report the calculated characteristics of nonnatural triplex-forming oligonucleotide (TFO) bases recognizing base-pair reversals (TA-->AT) in a double-helical DNA sequence. Ab initio and molecular mechanics calculations have been carried out to characterize the geometric and energetic consequences at the base-pair reversal sites. We have estimated the free energies of solvation of the natural and proposed bases by solving the linearized Poisson-Boltzmann equation. The calculations indicate that the proposed TFO bases should bind with some specificity to the duplex. Implications of the strategy used in the context of molecular biology is discussed.

The opsX locus of Xanthomonas campestris affects host range and biosynthesis of lipopolysaccharide and extracellular polysaccharide.

Xanthomonas campestris pv. citrumelo strain 3048 is the causal agent of citrus bacterial leaf spot disease and has a wide host range that includes rutaceous and leguminous plants. A spontaneous prototrophic mutant of strain 3048 (strain M28) that had lost virulence on citrus but retained virulence on bean plants was recovered. Growth studies in planta showed that M28 cells died rapidly in citrus leaves but grew normally in bean leaves. In addition to the loss of citrus-specific virulence, M28 displayed the following mutant phenotypes in culture: decreased growth rate, reduction of the amount of exopolysaccharide (to ca. 25% of the amount in 3048), loss of capsules, and significant alterations of the two 3048 lipopolysaccharide (LPS) bands visualized by silver stain on polyacrylamide gels, consistent with a defect(s) in LPS assembly. A 38-kb DNA fragment from a 3048 total DNA library that complemented the mutant phenotypes of M28 was identified. The 38-kb fragment did not hybridize to two similarly sized fragments carrying different hrp (hypersensitive response and pathogenicity) genes cloned from 3048. Subcloning, DNA sequence analyses, and gene disruption experiments were used to identify a single gene, opsX (for outer-membrane polysaccharide), responsible for the mutant phenotypes of M28. At least one other gene downstream from opsX also affected the same phenotypes and may be part of a gene cluster. We report here the DNA sequence and transcriptional start site of opsX. A search of protein sequence data bases with the predicted 31.3-kDa OpsX sequence found strong similarity to Lsi-1 of Neisseria gonorrhoeae and RfaQ of Escherichia coli (both are involved in LPS core assembly). The host-specific virulence function of opsX appears to involve biosynthesis of the extracellular polysaccharide and a complete LPS. Both may be needed in normal amounts for protection from citrus, but not bean, defense compounds.

Inhibition of brain cell excitability by lidocaine, QX314, and tetrodotoxin: a mechanism for analgesia from infused local anesthetics?

Local anesthetic infusions have been used to provide analgesia in a variety of painful conditions. The mechanism for this drug effect remains unknown. To better define the electrical effects of lidocaine concentrations comparable to those obtained during analgesic infusions, lidocaine (0.05-3 mmol.l-1), QX314 (an obligatorily charged, quaternary lidocaine derivative applied within the cells), and tetrodotoxin (10 mmol.l-1) were applied to rat hippocampal pyramidal cells. The three drugs, which inhibit Na+ currents by varying mechanisms, produced tonic increases in (firing) current threshold, and decreases in the amplitude of action potentials measured using an intracellular microelectrode technique. Lidocaine inhibited action potential spikes and increased current threshold in a concentration-dependent fashion. Lidocaine 50 and 100 mumol.l-1 did not inhibit action potentials, but increased firing threshold by nearly 100%. Lidocaine 1-3 mmol.l-1 significantly inhibited action potential amplitude and increased threshold by as much as 800%. Similarly, QX314 and tetrodotoxin produced greater increases in current threshold than in action potential amplitude. QX314 produced phasic (or frequency-dependent) block during trains of stimuli at 1 Hz, even when almost no tonic block was present. Lidocaine produced less phasic block than QX314, and required both greater tonic block and more frequent stimulation to produce the phenomenon. Tetrodotoxin demonstrated no phasic block. Increases in current threshold occurred in lidocaine concentrations associated with analgesia and toxicity; inhibition of action potentials occurred scarcely at all at these concentrations. Thus, tonic increases in current threshold may underlie analgesia and supplementation of general anesthesia by intravenous lidocaine.

The use of ultrathin-layer polyacrylamide gel isoelectric focusing in two-dimensional analysis of plant and fungal proteins.

Although use of ultrathin polyacrylamide gel isoelectric focusing in the first dimension of two-dimensional analysis bestows a number of advantages, it has been little used by the plant science community. Nonstandardization along with problems unique to the format have probably delayed wider adoption. Relevant parameters were therefore tested in order to optimize resolution, reproducibility, economy and ease of use. Ultrathin-layer gels (200 microns in this study) used in the first dimension require a semirigid backing for support. Widely available matte-finished thin polyester film without chemical pretreatment was found to bind the gel adequately. The gel adheres to the film through all processing steps, yet, if desired, can be easily transferred to Whatman 3MM paper for special applications such as Western blotting. The ultrathin first-dimensional gels can be quickly dried on the polyester backing for convenient handling and long term storage. Strips cut from the dried gel for use in the second dimension are more easily manipulated than their tube format counterparts. The difficulty of disrupting and recovering microsamples of labeled leaf and root tissue prompted the invention of an efficient and simple communition device. An economical and efficient silver stain process is also described. This analytical technique was applied in an attempt to detect resistance gene products in different genetic backgrounds of maize. Although the ultrathin flatbed format provides as good as or better resolution than the tube gel system, the level of sensitivity was still inadequate to reveal the apparently rare resistance gene product.

Partial Purification and Characterization of d-Ribose-5-phosphate Reductase from Adonis vernalis L. Leaves.

This study presents evidence for a new enzyme, d-ribose-5-P reductase, which catalyzes the reaction: d-ribose-5-P + NADPH + H(+) --> d-ribitol-5-P + NADP(+). The enzyme was isolated from Adonis vernalis L. leaves in 38% yield and was purified 71-fold. The reductase was NADPH specific and had a pH optimum in the range of 5.5 to 6.0. The Michaelis constant value for d-ribose-5-P reduction was 1.35 millimolar. The enzyme also reduced d-erythrose-4-P, d-erythrose, dl-glyceraldehyde, and the aromatic aldehyde 3-pyridinecarboxaldehyde. Hexoses, hexose phosphates, pentoses, and dihydroxyacetone did not serve as substrates. d-Ribose-5-P reductase is distinct from the other known ribitol synthesizing enzymes detected in bacteria and yeast, and may be responsible for ribitol synthesis in Adonis vernalis.

Sorbitol metabolism and sink-source interconversions in developing apple leaves.

In apple (Malus domestica Borkh.) sorbitol is the primary product of photosynthesis, the major translocated form of carbon, and a common fruit constituent and storage compound. Previous work on sorbitol metabolism has revealed a NADPH-dependent aldose 6-phosphate reductase (A6PR) in green tissues, and a NAD-dependent sorbitol dehydrogenase in nongreen tissues. Results here show a decrease in sorbitol dehydrogenase activity and an increase in A6PR activity as leaves developing in the spring undergo the transition from sink to source. Sorbitol dehydrogenase activity reached a minimum as A6PR peaked. These changes were related to increases in leaf carbohydrate levels, especially sorbitol, and to increases in rates of net photosynthesis. Studies conducted in the autumn on senescing leaves also showed changes in enzyme activites, leaf carbohydrate levels, and photosynthesis. At this time, however, sorbitol dehydrogenase increased in specific activity, whereas A6PR activity, leaf carbohydrates, and photosynthetic rates all decreased substantially. Other experiments showed differences in the ability of young and mature leaves to metabolize sorbitol and in the distribution of sorbitol enzymes in leaves at transitional developmental stages. The results suggest that sorbitol metabolism in apple is tightly controlled and may be related to mechanisms regulating partitioning or source and sink activity.