Effects of Soil Characteristics on Spring-Harvested Switchgrass Biomass Composition

Switchgrass (Panicum virgatum L.) is a promising bioenergy crop for temperate regions. Overwintering has been used to improve biomass quality, resulting in a more efficient combustion, partially due to a reduction in minerals concentration. This study examines the effects of soil composition on overwintered switchgrass composition. Samples were collected in the spring from 58 environments in Southern Quebec to determine possible relationships between soil composition and biomass quality. Principal component analysis and stepwise regressions were used to identify relationships between soil and biomass compositions. Soil parameters monitored explained 74% of the variation in biomass silicon (Si) concentration, 45% of the variation in ash, and 32% of the variation in magnesium (Mg). Soil composition had limited effects on the concentration of other elements in switchgrass biomass. Switchgrass biomass quality is influenced by soil composition and appears well suited to biomass combustion when overwintered and harvested in the spring.     

Preliminary Study on the Activity of Phycobiliproteins against Botrytis cinerea

Phycobiliproteins (PBPs) are proteins of cyanobacteria and some algae such as rhodophytes. They have antimicrobial, antiviral, antitumor, antioxidative, and anti-inflammatory activity at the human level, but there is a lack of knowledge on their antifungal activity against plant pathogens. We studied the activity of PBPs extracted from Arthrospira platensis and Hydropuntia cornea against Botrytis cinerea, one of the most important worldwide plant-pathogenic fungi. PBPs were characterized by using FT-IR and FT-Raman in order to investigate their structures. Their spectra differed in the relative composition in the amide bands, which were particularly strong in A. platensis. PBP activity was tested on tomato fruits against gray mold disease, fungal growth, and spore germination at different concentrations (0.3, 0.6, 1.2, 2.4, and 4.8 mg/mL). Both PBPs reduced fruit gray mold disease. A linear dose–response relationship was observed for both PBPs against disease incidence and H. cornea against disease severity. Pathogen mycelial growth and spore germination were reduced significantly by both PBPs. In conclusion, PBPs have the potential for being also considered as natural compounds for the control of fungal plant pathogens in sustainable agriculture.     

Effects of clomipramine hydrochloride on heart rate and rhythm in healthy dogs

OBJECTIVE: To determine the effects of clomipramine hydrochloride on heart rate and rhythm in dogs. ANIMALS: 17 healthy Beagles. PROCEDURES: In experiment 1, 8 dogs received placebo or clomipramine (20 mg/kg of body weight, q 24 h, PO) for 7 days in a 2-way crossover design. In experiment 2, 9 dogs were evaluated for 48 hours before and 24 hours after oral administration of clomipramine (4 or 12 mg/kg) in a 2-way crossover design. Electrocardiogram and heart rate were monitored continuously by use of telemetry. RESULTS: A significant diurnal rhythm in heart rate was detected; minimum values were recorded at night. Administration of 20 mg of clomipramine/kg induced a significant reduction in heart rate, with peak effect achieved approximately 12 hours after dosing. Administration of 4 or 12 mg of clomipramine/kg did not result in significant changes in heart rate. Sinoatrial and second-degree atrioventricular block and ventricular escape beats were observed during periods of slow heart rate in more dogs that received clomipramine (3 to 4 of 8 dogs), compared with dogs that received placebo (1 to 2 of 8 dogs), but this difference was not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Short-term administration of clomipramine induced benign cardiovascular effects in dogs rather than the potentially dangerous arrhythmias or tachycardia reported following administration of tricyclic antidepressants to humans. Precautions regarding cardiovascular effects may not be needed for the use of clomipramine in healthy dogs.     

Impact of Endocrine‐Disrupting Chemicals on Reproductive Function in Zebrafish (Danio rerio)

The prevalence of endocrine‐disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex‐steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild‐type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure.     

Evaluation of Physicochemical Methods for Treatment of Cu, Pb, Sb, and Zn in Canadian Small Arm Firing Ranges Backstop Soils

This paper presents the results of physicochemical treatment on Pb-, Cu-, Sb-, and Zn-contaminated Canadian small arm firing range (SAFR) backstop soils in order to evaluate the potential of such methods for remediation of SAFR backstop soils. Remediation target for the treatment assays was to attain the Québec Department of Environment commercial C criterion or more realistically, to reach the soil burial D criterion. Two treatment lines (TL) were evaluated. TL-1, consisting of jig and Wilfley table (WT) treatments on the 0.5–3 mm and 53–500 μm soil size fractions (SF), respectively, and chemical leaching on the <53 μm SF and TL-2, consisting of jig on the 1–4 mm SF, spiral, and WT treatments on 250 μm–1 mm SF, and Kelsey jig assays on the <250 μm SF. For both TL, the untreated SF (>3 mm for TL-1; >4 mm for TL-2), and the gravimetric separation concentrates could be sent for recycling in smelter facilities. Results showed that the finer SF (<53 μm SF for TL-1; <250 μm SF for TL-2) were very difficult to treat. Even with metal removed mass proportions up to 78% for Pb, concentrations were still very high after chemical leaching; and the Kelsey jig showed deceiving metal removed mass proportions (up to 47% for Pb). In both TL, the jig and the WT showed Pb removed mass proportions up to 98% and treated mass proportions up to 77% in their respective SF. Whole process efficiencies in the cleaned soils showed that TL-1 led to the remediation of up to 65% of the initial total soil, and TL-2, 36%. TL-1 and TL-2 results showed that the WT effectively treated soils of 53 μm–1 mm SF, and the jig, soils of the 1–4 mm SF. Our study shows that gravimetric concentration techniques are very promising for the treatment of SAFR backstop soils, and further research has to be done in order to treat the SF lower than 53 μm.     

Probable transmission between animals of a plasmid encoding aminoglycoside 3-N-acetyltransferase IV and dihydrofolate reductase I

Ten aminoglycoside-resistant Escherichia coli isolated from the faeces of healthy or diarrhoeic animals reared in the same herd were studied. These strains were resistant to high levels of apramycin and low levels of gentamicin. They were also resistant to streptomycin, tetracycline, trimethoprim and some to ampicillin, chloramphenicol, kanamycin or nalidixic acid. Two strains, isolated from a calf and a lamb, respectively, belonged to the same biotype. All the transconjugants resistant to gentamicin-apramycin were also resistant to streptomycin, tetracycline and trimethoprim. In all cases, these resistances were encoded by plasmids of 100 kb. Analysis of these plasmids by agarose gel electrophoresis after digestion by EcoRI or BamHI revealed their similarity. Hybridization with a 500-bp HpaI insert of plasmid pFE872 was observed with DNA from field strains and their transconjugants, demonstrating the presence on the 100-kb plasmids of the gene coding for a dihydrofolate reductase I. A single plasmid, designated pIP1831, could be observed in identical or different strains isolated from calves or lambs, suggesting the transmission of strains and plasmids between animals of different species.