Influence of two management practices in the Canadian Prairies on radiative forcing.

Surface albedo and soil carbon sequestration are influenced by agricultural management practices which impact the Earth's radiation budget and climate change. In this study we investigate the impact of reduced summer fallowing and reduced tillage in the Canadian Prairies on climate change by estimating the change in radiative forcing due to albedo and soil carbon sequestration. Seasonal variations of albedo, which are dependent on agricultural management practices and soil colour in three soil zones, were derived from 10-day composite 250-m Moderate Resolution Imaging Spectroradiometer (MODIS) data. Using this information, we found an overall increase of surface albedo due to the conversion from summer fallowing to continuous cropping and from conventional tillage (CT) to either no-tillage (NT) or reduced tillage (RT). The increase was dependent on soil brightness, type of vegetation and snow cover. Using data from the Census of Agriculture and taking into consideration both albedo and soil carbon changes, we estimated that from 1981 to 2016, the total radiative forcing for the cropland area in the Canadian Prairies was -405 µW m-2 due to the conversion of CT to either NT or RT and about 70% was due to the change in albedo. During the same period, the total radiative forcing was -410 µW m-2 due to a reduction in the area under summer fallow and about 62% was due to the change in albedo. The equivalent atmospheric CO2 drawdown from these two management changes from albedo change was about 7.8 and 8.7 Tg CO2 yr-1, respectively. These results demonstrate that it is important to consider both the changes of soil carbon and surface albedo in evaluating climate change impacts due to agricultural management practices.

First Report of Damping-Off of Durum Wheat Caused by Arthrinium sacchari in the Semi-Arid Saskatchewan Fields.

Durum wheat (Triticum durum Desf.) is an important crop in western Canada. In 2005, Arthrinium sacchari was frequently isolated from soil and durum wheat plants of the semi-arid fields of Swift Current, Saskatchewan, Canada (50°16'N, 107°44'W). The susceptibility of durum wheat to damping-off caused by this fungus was evaluated. To our knowledge, this is the first report of A. sacchari in North America (1) and the first mention of its association with durum wheat. DNA was extracted (MoBio Isolation Kit, Carlsbad, CA) from 2-week-old A. sacchari isolates (FBC.3, FBC.45, and FBC.143) grown on PDA. The internal transcribed spacer (ITS) of the rDNA was amplified from each isolate and sequenced (Plant Biotechnology Institute, Saskatoon, SK, Canada) and similarity analyses were performed using the BLAST search algorithm in GenBank. All three sequences (Accession Nos. EF076710, EF076711, and EF076712A) showed 99% similarity with A. sacchari (Accession No. AF393679). An in vitro assay was performed by placing 1-cm2 agar plugs containing mycelia of A. sacchari (FBC.3, FBC.45, and FBC.143) onto surface-sterilized durum. Surface-sterilized seeds inoculated in the same way with Fusarium graminearum or F. avenaceum were used as negative controls, and noninoculated surface-sterilized seeds were used as a positive control. A second in vitro assay involved inoculating the same isolates onto seeds placed in sterilized sandy soil. In both assays, 10 seeds per petri plate and three plates per treatment were used and plates were incubated at 21°C for 1 week in darkness. All experiments were performed twice. On PDA, preemergence damping-off was found in 60% of A. sacchari FBC.3, 55% of A. sacchari FBC.45 and FBC.143, 50% of F. avenaceum, and 58% of F. graminearum inoculated seeds. In sterilized soil, the incidence of preemergence damping-off ranged from 43 to 30%. Subsequent incubation over a period of 3 weeks resulted in 100% postemergence damping-off in A. sacchari FBC.45 and FBC.3 as well as in both Fusarium spp. inoculated controls, 60% postemergence damping-off in A. sacchari FBC.143, and no damping-off in the noninoculated control. Arthrinium and Fusarium spp. were reisolated only from symptomatic plants, satisfying Koch's postulates. In conclusion, durum wheat is highly susceptible to damping-off caused by A. sacchari, showing characteristic dark brown or violet lesions in infected tissues. A. sacchari was previously reported to be present in South America and eastern Asia. In China, it is considered an important mycotoxigenic species (2). Thus, infection of durum wheat crops with A. sacchari could pose a significant threat to North American wheat production. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2006. (2) X. J. Liu et al. Acta Mycol. Sinica 7:221, 1988.

Measurement of conjugated diene lipids by derivative spectroscopy in heptane extracts of plasma.

A series of experiments are described which show that second derivative spectroscopy can be used to quantify conjugated lipid dienes as markers of lipid peroxidation in heptane extracts of plasma from patients with rheumatoid arthritis, osteoarthritis, and healthy controls. Results obtained by this method gave reasonable agreement with those derived from the measurement of simple absorbance in chloroform/methanol extracts. Two minima were observed in the derivative spectrum of plasma lipid extracts. These minima occurred at 233 and 241 nm and corresponded to absorbance maxima in the conventional UV spectrum. Using a combination of phospholipase hydrolysis, reverse phase high performance liquid chromatography (HPLC) and second derivative spectroscopy we confirmed that these two minima can be attributed to a single fatty acid (9 cis-, 11 trans-linoleic acid) shown previously to account for greater than 90% of diene conjugation in human plasma samples. When the biological isomer 9 cis-, 11 trans-linoleic acid was separated by reverse phase HPLC from the mixture of other plasma phospholipid-2-esterified fatty acids we observed a change in derivative spectroscopy minima from 233 and 241 nm to 228 and 237 nm. Minima at the latter two wavelengths were also seen with pure preparations of the Paint Research Isomer (9 trans-, 11 trans-linoleic acid) which eluted later than biological 9 cis-, 11 trans-linoleic acid using reverse phase HPLC, suggesting that the absorption spectra of these pure cis-, trans and trans, trans dienes are similar but can be altered by the presence of other fatty acids in the extract.

Multisubstrate isotope labeling and metagenomic analysis of active soil bacterial communities.

Soil microbial diversity represents the largest global reservoir of novel microorganisms and enzymes. In this study, we coupled functional metagenomics and DNA stable-isotope probing (DNA-SIP) using multiple plant-derived carbon substrates and diverse soils to characterize active soil bacterial communities and their glycoside hydrolase genes, which have value for industrial applications. We incubated samples from three disparate Canadian soils (tundra, temperate rainforest, and agricultural) with five native carbon ((12)C) or stable-isotope-labeled ((13)C) carbohydrates (glucose, cellobiose, xylose, arabinose, and cellulose). Indicator species analysis revealed high specificity and fidelity for many uncultured and unclassified bacterial taxa in the heavy DNA for all soils and substrates. Among characterized taxa, Actinomycetales (Salinibacterium), Rhizobiales (Devosia), Rhodospirillales (Telmatospirillum), and Caulobacterales (Phenylobacterium and Asticcacaulis) were bacterial indicator species for the heavy substrates and soils tested. Both Actinomycetales and Caulobacterales (Phenylobacterium) were associated with metabolism of cellulose, and Alphaproteobacteria were associated with the metabolism of arabinose; members of the order Rhizobiales were strongly associated with the metabolism of xylose. Annotated metagenomic data suggested diverse glycoside hydrolase gene representation within the pooled heavy DNA. By screening 2,876 cloned fragments derived from the (13)C-labeled DNA isolated from soils incubated with cellulose, we demonstrate the power of combining DNA-SIP, multiple-displacement amplification (MDA), and functional metagenomics by efficiently isolating multiple clones with activity on carboxymethyl cellulose and fluorogenic proxy substrates for carbohydrate-active enzymes. Importance: The ability to identify genes based on function, instead of sequence homology, allows the discovery of genes that would not be identified through sequence alone. This is arguably the most powerful application of metagenomics for the recovery of novel genes and a natural partner of the stable-isotope-probing approach for targeting active-yet-uncultured microorganisms. We expanded on previous efforts to combine stable-isotope probing and metagenomics, enriching microorganisms from multiple soils that were active in degrading plant-derived carbohydrates, followed by construction of a cellulose-based metagenomic library and recovery of glycoside hydrolases through functional metagenomics. The major advance of our study was the discovery of active-yet-uncultivated soil microorganisms and enrichment of their glycoside hydrolases. We recovered positive cosmid clones in a higher frequency than would be expected with direct metagenomic analysis of soil DNA. This study has generated an invaluable metagenomic resource that future research will exploit for genetic and enzymatic potential.

Systems level modeling of the cell cycle using budding yeast.

Proteins involved in the regulation of the cell cycle are highly conserved across all eukaryotes, and so a relatively simple eukaryote such as yeast can provide insight into a variety of cell cycle perturbations including those that occur in human cancer. To date, the budding yeast Saccharomyces cerevisiae has provided the largest amount of experimental and modeling data on the progression of the cell cycle, making it a logical choice for in-depth studies of this process. Moreover, the advent of methods for collection of high-throughput genome, transcriptome, and proteome data has provided a means to collect and precisely quantify simultaneous cell cycle gene transcript and protein levels, permitting modeling of the cell cycle on the systems level. With the appropriate mathematical framework and sufficient and accurate data on cell cycle components, it should be possible to create a model of the cell cycle that not only effectively describes its operation, but can also predict responses to perturbations such as variation in protein levels and responses to external stimuli including targeted inhibition by drugs. In this review, we summarize existing data on the yeast cell cycle, proteomics technologies for quantifying cell cycle proteins, and the mathematical frameworks that can integrate this data into representative and effective models. Systems level modeling of the cell cycle will require the integration of high-quality data with the appropriate mathematical framework, which can currently be attained through the combination of dynamic modeling based on proteomics data and using yeast as a model organism.

Disease-modifying antirheumatic drugs: gold, penicillamine, antimalarials, and sulfasalazine.

In the assessment of the effects of disease-modifying antirheumatic drugs, three or four clinical measurements supported by the erythrocyte sedimentation rate, and sometimes radiographs, are generally agreed to be correct. Some advocate functional assessments also, or even alternatively. Several studies compared gold, penicillamine, antimalarials, and sulfasalazine either with each other or with placebo, and occasionally with methotrexate. No important differences between the general performance of the four drugs were found. More work was reported on sulfasalazine than on the other three drugs; the data support that it has a place in our armamentarium. Several important contributions concerned strategies of treatment. It is considered that disease-modifying antirheumatic drugs should be used earlier and more aggressively in rheumatoid arthritis. This aspect was perhaps the key note of the 1990 literature on this topic. As part of the new strategies, combination therapy is urged by some rheumatologists, whereas others urge caution on the grounds that we do not yet know enough about the effects of combinations, or by how much the risks of adverse effects are increased in combination.

It is said that elevated erythrocyte sedimentation rate and the elevation of C-reactive protein (CRP) may be indicators of continuing joint destruction in rheumatoid arthritis. What then is the explanation for joint destruction in some patients in whom there is no such apparent elevation of either the sedimentation rate of CRP?

It is said that elevated erythrocyte sedimentation rate and the elevation of C-reactive protein (CRP) may be indicators of continuing joint destruction in rheumatoid arthritis. What then is the explanation for joint destruction in some patients in whom there is no such apparent elevation of either the sedimentation rate or CRP?

Effects of rifampicin with and without isoniazid in rheumatoid arthritis.

A patient with rheumatoid arthritis (RA) experienced great improvement in her RA when given antituberculous treatment for pulmonary tuberculosis (TB). Two of the drugs used in TB, rifampicin and isoniazid, include immunomodulatory effects among their properties. To investigate whether these drugs have any effect in RA, we studied 20 patients who were given either rifampicin 600 mg daily (10 patients) or rifampicin 600 mg with isoniazid 300 mg daily (10 patients). Eighteen patients completed at least 3 months' treatment. Six of the 7 patients with early RA (less than 3 years) improved; their median erythrocyte sedimentation rate fell from 43.5-10 mm/h (p = 0.036) and median serum C-reactive protein from 40-0 mg/l (p = 0.036). Eleven patients with longer histories of RA did not improve. Our results suggest rifampicin with or without isoniazid may be effective in RA.

Outcome of attempts to treat rheumatoid arthritis with gold, penicillamine, sulphasalazine, or dapsone.

The outcome of attempts to continue treatment indefinitely with either gold, penicillamine, sulphasalazine, or dapsone was studied in 240 patients with rheumatoid arthritis (RA). The usual reason for discontinuing treatment was the occurrence of an adverse effect. This led to 53% of patients stopping gold, 33% sulphasalazine, 32% penicillamine, and 17% dapsone. The next most frequent reason was that the drug was ineffective, leading to discontinuation in 37% of patients having dapsone, 24% sulphasalazine, 19% penicillamine, and 16% gold. Other reasons for stopping treatment were infrequent. The high discontinuation rate of these drugs over 2 years in part accounts for the conflict of opinion on whether they can alter the course of RA; their efficacy must to a large extent be governed by their acceptability.

Relationship between erythrocyte sedimentation rate and serum C-reactive protein in rheumatoid arthritis.

Serum C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were compared in 241 patients with rheumatoid arthritis (RA). There was a positive linear correlation between the 2 measurements with a high degree of variability. Neither age nor duration of RA had a detectable influence. The relationship between CRP and ESR was, however, altered by treatment with gold, penicillamine, or high doses of prednisone. It is suggested that serum CRP is the more sensitive measurement, but that CRP and ESR do not have identical clinical significance.

Does sulphasalazine cause folate deficiency in rheumatoid arthritis?

Sulphasalazine impairs folic acid absorption and metabolism but rarely leads to folate deficiency in inflammatory bowel disease (IBD). In rheumatoid arthritis (RA), however, serum and red cell folate concentrations are often low and sulphasalazine might stress folate metabolism. In a prospective study, 2 g sulphasalazine was compared with 500 mg penicillamine daily in 30 patients over 24 weeks. Pre-treatment serum and red cell folate concentrations were low-normal. Improvements in disease activity and haemoglobin occurred in both treatment groups, but MCV increased only in patients taking sulphasalazine. Serum and red cell folate concentrations did not change in either group. Increased MCV with sulphasalazine might therefore reflect reticulocytosis secondary to drug-induced haemolysis. The mechanisms by which sulphasalazine antagonizes folate metabolism are dose-dependent and, consequently, higher doses might precipitate folate deficiency.

Clinical and laboratory effects of prolonged therapy with sulfasalazine, gold or penicillamine: the effects of disease duration on treatment response.

Serial observations for up to 5 years of clinical score (a subjective global assessment), serum C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were analyzed in 3 groups of patients with active rheumatoid arthritis (RA) requiring treatment with a second line drug. The groups comprised 315 patients (243 women, 72 men) who had sulfasalazine (SAS); 203 patients (141 women, 62 men) who had sodium aurothiomalate (gold) and 163 patients (131 women, 32 men) who had penicillamine. The groups matched in most respects but the gold group had a smaller proportion of women, a shorter median disease duration and a higher median CRP than the remaining 2 groups. The penicillamine group contained a higher proportion of seropositive patients. In each group there were significant improvements in clinical score, CRP and ESR for all time points from 6 to 30 months; these improvements were maintained for longer (up to 60 months for SAS) in the SAS and gold groups but the differences between the drugs after 30 months were probably a consequence of falling number of patients, not differing drug potencies. The mean ESR and CRP levels fell to about 30 mm/h and 20-30 mg/l, respectively. Response was defined as (1) treatment duration greater than 6 months, (2) clinical score improvement greater than 4 by 6 months, (3) ESR fall to less than 30 mm/h by 6 months. By these criteria 142 of 681 patients (20.9%) responded; the response rates were SAS 20.3%, gold 24.1%, penicillamine 17.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of antirheumatic drugs on circulating immune complexes in rheumatoid arthritis.

The relationship between antirheumatic drug treatment and levels of circulating immune complexes (125I-C1q binding activity) has been investigated in a prospective two-year study of patients with rheumatoid arthritis using the erythrocyte sedimentation rate (ESR) and serum C-reactive protein concentration as indices of disease activity. Twenty-eight patients were treated with non-steroid anti-inflammatory drugs, 14 patients had 'second line' drugs and 13 patients were treated with adrenal corticosteroids. Serum 125I-C1q binding activity did not change during non-steroid anti-inflammatory drug treatment; however, immune complex levels did fall during treatment with new (ICI 55,897, sulphasalazine) and established (gold, penicillamine) second line drugs. Serum 125I-C1q binding activity reflected the response to treatment shown by serum C-reactive protein and ESR. Serum C-reactive protein concentration and ESR fell with all doses of adrenal corticosteroids. In contrast, immune complex levels did not fall when doses of adrenal corticosteroids were below 20 mg/day prednisolone. 125I-C1q binding activity fell during high dose adrenal corticosteroid therapy (greater than 40 mg/day prednisolone; 1 g methylprednisolone infusions). Serial measurements of 125I-C1q binding activity correspond to ESR and the serum C-reactive protein concentration in distinguishing between anti-inflammatory drugs, which provide symptomatic relief only, and second line drugs which may retard disease progression. The fall in circulating immune complex levels during 'high' dose corticosteroid treatment, but not during 'low' dose treatment, suggests that corticosteroids have a dose-dependent effect on the immune system in addition to their anti-inflammatory properties.

Rheumatoid arthritis: the effects of treatment with dapsone on hemoglobin.

Hemoglobin concentration (Hb) was measured at 6 week intervals for up to a year in 84 patients with rheumatoid arthritis treated with dapsone. During the first 6 weeks, mean Hb decreased from 12.0 to 11.0 g/dl (p less than 0.001). Falls in Hb occurred in 81% of patients but exceeded 2 g/dl in only 10%. After more than 6 weeks of treatment mean Hb increased, though a few individuals became anemic during this period. Anemia led to discontinuation of dapsone in 5 (6%) patients. Men and patients receiving corticosteroids had higher pretreatment Hb values; after falls in mean Hb at 6 weeks, recovery was more rapid in these 2 subgroups. Changes in Hb produced by 100 mg and 150 mg dapsone daily were similar.

Long-term treatment of rheumatoid arthritis with sulphasalazine, gold, or penicillamine: a comparison using life-table methods.

Life-table analysis was applied to the records of 317 patients with rheumatoid arthritis (RA) treated with sulphasalazine (SAS), 201 treated with sodium aurothiomalate (gold), and 163 with penicillamine. They comprised all those treated in our department with these drugs between January 1973 and July 1984. Risks of treatment termination for all reasons were similar for each drug at five years (gold 92%, penicillamine 83%, SAS 81%). The risk of treatment termination due to inefficacy was less for gold (29.5%) than for penicillamine (38.1%) or sulphasalazine (41.2%). Adverse effects, however, led to withdrawal of gold in 57%, penicillamine in 41.2%, and SAS in 37%; the most effective drugs appeared most toxic. Serious adverse effects were much more common in association with gold (17.4%) and penicillamine (12.3%) than with SAS (1.6%). Sulphasalazine appears as well tolerated over long periods in RA as gold or penicillamine and is associated with fewer serious adverse effects; of these drugs, it might therefore be considered the agent of first choice.