Are two cultivars better than one? Performance of leafed and semi-leafless pea mixtures under weedy conditions

Non-Peer ReviewedThere is a need for improved tools to minimize yield losses due to weeds for organic field pea production. Cultivar mixtures may improve the ability of organic pulse crops to suppress weeds and maintain yields in the presence of weeds. While semi-leafless peas are known for their lodging resistance and high yield potential in the absence of weeds, leafed (wild-type) peas may provide better weed suppression and yield stability in the presence of weeds. A replicated field experiment was conducted on organic land over five site-years to test the hypothesis that mixtures of leafed and semi-leafless field pea cultivars would improve weed suppression and yields relative to monocultures of the same cultivars. The experiment tested factorial combinations of five ratios of semi-leafless (cv. CDC Patrick or CDC Dakota), and leafed pea (cv. CDC Sonata) (0:100, 25:75, 50:50, 75:25, and 100:0, respectively), and two target seeding rates (88 and 132 plants m-2). Plots were monitored for crop and weed emergence, biomass, and yields. Mixtures differed from their component monocultures in both weed control and yields. Levels of weed control in mixtures were intermediate to the component cultivars, and no weed control benefits were seen. While CDC Patrick mixtures did not out-yield CDC Patrick monocultures, mixtures of 75% CDC Dakota and 25% CDC Sonata out-yielded both respective monocultures by 12-196%. Results indicate that mixtures of leafed and semi-leafless cultivars may be used to improve organic pea yields in the presence of weeds. However, specific combinations of cultivars and mixing ratios should be evaluated on a case-by-case basis

Organic production tools for field peas: are cultivar mixtures more competitive with weeds?

Non-Peer ReviewedWithin Saskatchewan’s organic industry there is a need for improved tools to minimize yield losses due to weeds. Cultivar mixtures may improve the ability of organic pulse crops to suppress weeds and maintain yields in the presence of weeds. While semileafless peas are known for their lodging resistance and high yield potential in the absence of weeds, conventional peas may provide better weed suppression and yield stability in the presence of weeds. A replicated field experiment was conducted at two organic field sites to test the hypothesis that cultivar mixtures of conventional and semileafless field pea would differ in weed suppression and yields. The experiment tested factorial combinations of five ratios of semileafless pea cultivar CDC Dakota and conventional cultivar CDC Sonata (0:100, 25:75, 50:50, 75:25, and 100:0, respectively), and two seeding rates (conventional and organic recommended). Plots were monitored for crop and weed emergence, biomass, and yields. Significant differences were observed among the different ratios of semileafless and conventional field pea. Results indicate that the semileafless cultivar was more competitive with weeds than the conventional. As the canopy composition progressed from a pure conventional canopy towards increasing percentages of semileafless pea in the mixture, total weed biomass decreased, and total crop yields increased. It was concluded that while no additional weed suppression or yield benefits were seen compared with growing the more strongly competitive semileafless cultivar alone, cultivar mixtures reduced the risk associated with growing unfamiliar or less competitive cultivars by stabilizing weed suppression and crop yields at a level between the two components of the mixture

How can drones be used for crop diagnostics?

Non-Peer Reviewe

COMPARISON OF MODIFICATION SITES FORMED ON HUMAN SERUM ALBUMIN AT VARIOUS STAGES OF GLYCATION

Background—Many of the complications encountered during diabetes can be linked to the nonenzymatic glycation of proteins, including human serum albumin (HSA). However, there is little information regarding how the glycation pattern of HSA changes as the total extent of glycation is varied. The goal of this study was to identify and conduct a semi-quantitative comparison of the glycation products on HSA that are produced in the presence of various levels of glycation. Methods—Three glycated HSA samples were prepared in vitro by incubating physiological concentrations of HSA with 15 mmol/l glucose for 2 or 5 weeks, or with 30 mmol/l glucose for 4 weeks. These samples were then digested and examined by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the glycation products that were formed. Results—It was found that the glycation pattern of HSA changed with its overall extent of total glycation. Many modifications including previously-reported primary glycation sites (e.g., K199, K281, and the N-terminus) were consistently found in the tested samples. Lysines 199 and 281, as well as arginine 428, contained the most consistently identified and abundant glycation products. Lysines 93, 276, 286, 414, 439, and 524/525, as well as the N-terminus and arginines 98, 197, and 521, were also found to be modified at various degrees of HSA glycation. Conclusions—The glycation pattern of HSA was found to vary with different levels of total glycation and included modifications at the 2 major drug binding sites on this protein. This result suggests that different modified forms of HSA, both in terms of the total extent of glycation and glycation pattern, may be found at various stages of diabetes. The clinical implication of these results is that the binding of HSA to some drug may be altered at various stages of diabetes as the extent of glycation and types of modifications in this protein are varied

Particulate Matter Exposure Exacerbates High Glucose-Induced Cardiomyocyte Dysfunction through ROS Generation

Diabetes mellitus and fine particulate matter from diesel exhaust (DEP) are both important contributors to the development of cardiovascular disease (CVD). Diabetes mellitus is a progressive disease with a high mortality rate in patients suffering from CVD, resulting in diabetic cardiomyopathy. Elevated DEP levels in the air are attributed to the development of various CVDs, presumably since fine DEP (<2.5 µm in diameter) can be inhaled and gain access to the circulatory system. However, mechanisms defining how DEP affects diabetic or control cardiomyocyte function remain poorly understood. The purpose of the present study was to evaluate cardiomyocyte function and reactive oxygen species (ROS) generation in isolated rat ventricular myocytes exposed overnight to fine DEP (0.1 µg/ml), and/or high glucose (HG, 25.5 mM). Our hypothesis was that DEP exposure exacerbates contractile dysfunction via ROS generation in cardiomyocytes exposed to HG. Ventricular myocytes were isolated from male adult Sprague-Dawley rats cultured overnight and sarcomeric contractile properties were evaluated, including: peak shortening normalized to baseline (PS), time-to-90% shortening (TPS90), time-to-90% relengthening (TR90) and maximal velocities of shortening/relengthening (±dL/dt), using an IonOptix field-stimulator system. ROS generation was determined using hydroethidine/ethidium confocal microscopy. We found that DEP exposure significantly increased TR90, decreased PS and ±dL/dt, and enhanced intracellular ROS generation in myocytes exposed to HG. Further studies indicated that co-culture with antioxidants (0.25 mM Tiron and 0.5 mM N-Acetyl-L-cysteine) completely restored contractile function in DEP, HG and HG+DEP-treated myocytes. ROS generation was blocked in HG-treated cells with mitochondrial inhibition, while ROS generation was blocked in DEP-treated cells with NADPH oxidase inhibition. Our results suggest that DEP exacerbates myocardial dysfunction in isolated cardiomyocytes exposed to HG-containing media, which is potentially mediated by various ROS generation pathways

Diabetes and the Risk of Multi-System Aging Phenotypes: A Systematic Review and Meta-Analysis

[[abstract]]Background: Observational studies suggested an association between diabetes and the risk of various geriatric conditions (i.e., cognitive impairment, dementia, depression, mobility impairment, disability, falls, and urinary incontinence). However, the magnitude and impact of diabetes on older adults have not been reviewed. Methodology/Principal Findings: MEDLINE and PSYCINFO databases were searched through November 2007 for published studies, supplemented by manual searches of bibliographies of key articles. Population-based, prospective cohort studies that reported risk of geriatric outcomes in relation to diabetes status at baseline were selected. Two authors independently extracted the data, including study population and follow-up duration, ascertainment of diabetes status at baseline, outcomes of interest and their ascertainment, adjusted covariates, measures of association, and brief results. Fifteen studies examined the association of DM with cognitive dysfunction. DM was associated with a faster decline in cognitive function among older adults. The pooled adjusted risk ratio (RR) for all dementia when persons with DM were compared to those without was 1.47 (95% CI, 1.25 to 1.73). Summary RRs for Alzheimer's disease and vascular dementia comparing persons with DM to those without were 1.39 (CI, 1.16 to 1.66) and 2.38 (CI, 1.79 to 3.18), respectively. Four of 5 studies found significant association of DM with faster mobility decline and incident disability. Two studies examined the association of diabetes with falls in older women. Both found statistically significant associations. Insulin users had higher RR for recurrent falls. One study for urinary incontinence in older women found statistically significant associations. Two studies for depression did not suggest that DM was an independent predictor of incident depression. Conclusions/Significance: Current evidence supports that DM is associated with increased risk for selected geriatric conditions. Clinicians should increase their awareness and provide appropriate care. Future research is required to elucidate the underlying pathological pathway. 2009 Lu et al

Multi-faceted approaches to weed management in pulse crops

Non-Peer Reviewe

LATE BLIGHT CONTROL ALTERNATIVES FOR ORGANIC POTATO GROWERS

SUMMARY Organic potato production is a flourishing sector of the British Columbia food industry and acreage dedicated to that crop is increasing. Late blight (Phytophthora infestans (Mont.) de Bary) is one of the largest production risks of the region&apos;s potato growers and has the potential to cause substantial economic losses. Consequently, prevention of foliar epidemics leads to weekly application of an arsenal of fungicides by the conventional growers. On the other hand, only one product, a formulation of copper hydroxide (Parasol WP), provides late blight protection for organic growers. The need for alternatives to copper led to testing of alternative, biological controls for the disease. This study tested two OMRI-listed, natural products, Actinovate SP® and Sonata®, alone or in combinations with each other and/or Parasol WP. The study consisted of six treatments: 1) Parasol sprayed, 2) Actinovate SP sprayed in rotation with Sonata 3) Actinovate SP sprayed 4) Actinovate SP sprayed in rotation with Parasol WP 5) Sonata sprayed 6) Sonata sprayed in rotation with Parasol WP, and 7) untreated (water) Control. Plots were treated weekly and leaves with active late blight lesions were introduced to plots. Late blight incidence and severity was assessed weekly. At harvest, tubers were assessed for yield and infection by P. infestans. Disease incidence on the last scoring date reached 29% in the Parasol/Parasol treatment, versus 52% of plants in the untreated Control

In vitro motility speed of slow myosin extracted from single soleus fibres from young and old rats

Isolated soleus muscle fibres from aged rats contract more slowly than those from young rats. To determine whether this effect is due to a difference between the myosin molecules, we measured the rate at which actin filaments are driven over a myosin coated surface in the presence of ATP by using a novel in vitro motility assay where myosin is extracted from single muscle fibre segments.Motility was dependent on the myosin density on the coverslip. In regions of high myosin density, actin motility was orientated parallel and anti-parallel to the direction of flow during myosin adhesion to the coverslip. In contrast, in regions of lower myosin density, actin motility was more random. The speed was about 20% higher in the high density regions (P < 0.001). Further, the speed of filaments in the high density region, moving away or towards the fibre was less variable (P < 0.05) than that of more randomly moving filaments in the low density region.The speed with myosin from slow soleus fibres of young adult rats (3–6 months old; v= 1.43 ± 0.23 μm s−1; mean ±s.d.) was faster (P < 0.001) than with myosin from aged rats (20–24 months old; v= 1.27 ± 0.23 μm s−1).No difference in myosin isoforms between young adult and aged fibres could be detected using electrophoretic and immunocytochemical techniques. Fibres of both ages expressed the β/slow myosin heavy chain (MyHC) isoform and slow isoforms of essential and regulatory myosin light chains (MyLCs).It is concluded that an age-related alteration in myosin contributes to the slowing of the maximum shortening velocity (V0) observed in soleus muscle fibres expressing the β/slow MyHC isoform