Evaluating an image analysis system for mapping white clover pastures

We have developed an image analysis system for mapping white clover pastures. The information from digital colour photographs is processed by software (Trifolium.exe) specially designed for the purpose. The software estimates the coverage of clover, weeds and bare ground, and the unidentified remainder of the total area is regarded as covered by grass. To evaluate the reliability of the estimates of clover content, the clover on paper printouts of non-processed images were marked manually and analysed by a photo scanner and commercially available software. The outputs from Trifolium.exe and the estimates from scanned manual markings were highly correlated (r ²=0.81). A sensitivity test was conducted to quantify the impact of changes of six user-adjustable parameters of Trifolium.exe. The software output of clover coverage was sensitive for changes in three, soil coverage for changes in one, and weed coverage for changes in all parameters. The fact that the digital image acquisition and analysis produce nearly continuous and exactly positioned data, implies further that it is a very appropriate tool for analyses of spatial dynamics in grass-clover pastures.     

Investigation of Two Magnetic Permanently Confined Micelle Array Sorbents Using Nonionic and Cationic Surfactants for the Removal of PAHs and Pesticides from Aqueous Media

Surfactants have been used for environmental remediation to remove hydrophobic organic compounds (HOCs) in water and soil. However, there are limited studies on the use of surfactants in confined micelle arrays to remove pesticides and polycyclic aromatic hydrocarbons from water. We studied the recovery of HOCs using two confined surfactants: nonionic Triton X-100 and cationic 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC). The micelle arrays were confined on a mesoporous silica matrix deposited onto a magnetic iron core. These magnetic, dispersible sorbents can be used to recover HOCs, minimizing the application of surfactants when compared to soil-washing techniques. The TPODAC-based sorbent had better average recovery of the HOCs studied compared to the Triton-X sorbent, and was, in general, comparable to activated carbon. It performed well with the chlorinated pesticides, in part due to additional interactions between the cationic sites and the polar compounds.     

Refrigerated Dough Quality of Hard Red Spring Wheat: Effect of Genotype and Environment on Dough Syruping and Arabinoxylan Production

Arabinoxylans (AX) are the main nonstarch polysaccharides found in wheat flour. Structural changes of AX in refrigerated dough are linked to deleterious effects on refrigerated dough quality during storage. The purpose of this research was to evaluate the effect of cultivar and growing environment on dough syruping during refrigerated storage in relation to apparent xylanase activity and AX chemistry in hard red spring (HRS) wheat. Eight HRS cultivars that were grown at six locations over two years in North Dakota were evaluated for dough syruping during 15 days of refrigerated storage. When compared with genotypic effect, growing environment had a greater impact on apparent xylanase activity and dough syruping; they were found to have significant associations by log‐linear regression analysis. Specifically, wheat samples produced in a dry environment had lower apparent xylanase activity and degree of dough syruping than those from a wet environment. Some HRS cultivars were identified to be consistently lower in apparent xylanase activity and dough syruping across all growing environments, indicating that those cultivars had more stability over growing environment than other cultivars. These results indicate that certain cultivars that are grown in relatively dry environments in North Dakota are more suitable for use in refrigerated dough formulations.     

Faecal shedding, alimentary clearance and intestinal spread of prions in hamsters fed with scrapie

Shedding of prions via faeces may be involved in the transmission of contagious prion diseases. Here, we fed hamsters 10mg of 263K scrapie brain homogenate and examined the faecal excretion of disease-associated prion protein (PrP(TSE)) during the course of infection. The intestinal fate of ingested PrP(TSE) was further investigated by monitoring the deposition of the protein in components of the gut wall using immunohistochemistry and paraffin-embedded tissue (PET) blotting. Western blotting of faecal extracts showed shedding of PrP(TSE) in the excrement at 24-72 h post infection (hpi), but not at 0-24 hpi or at later preclinical or clinical time points. About 5% of the ingested PrP(TSE) were excreted via the faeces. However, the bulk of PrP(TSE) was cleared from the alimentary canal, most probably by degradation, while an indiscernible proportion of the inoculum triggered intestinal infection. Components of the gut-associated lymphoid tissue (GALT) and the enteric nervous system (ENS) showed progressing accumulation of PrP(TSE) from 30 days post infection (dpi) and 60 dpi, respectively. At the clinical stage of disease, substantial deposits of PrP(TSE) were found in the GALT in close vicinity to the intestinal lumen. Despite an apparent possibility of shedding from Peyer's patches that may involve the follicle-associated epithelium (FAE), only small amounts of PrP(TSE) were detected in faeces from clinically infected animals by serial protein misfolding cyclic amplification (sPMCA). Although excrement may thus provide a vehicle for the release of endogenously formed PrP(TSE), intestinal clearance mechanisms seem to partially counteract such a mode of prion dissemination.     

Evaluation of the relationship between causative organisms and clinical characteristics of infective endocarditis in dogs: 71 cases (1992-2005)

OBJECTIVE: To evaluate microbiologic findings in dogs with infective endocarditis (IE) and determine whether there were differences in clinical features of disease caused by different groups of infective agents. DESIGN: Retrospective case series. ANIMALS: 71 dogs with suspected or definite IE. PROCEDURES: Medical records were reviewed for results of bacterial culture and susceptibility testing, serologic assays for vector-borne disease, and PCR testing on vegetative growths. Cases were grouped by causative organism and relationships among infectious agent group, and various hematologic, biochemical, and clinical variables were determined. Survival analyses were used to determine associations between infecting organisms and outcome. RESULTS: Causative bacteria were identified in 41 of 71 (58%) dogs. Gram-positive cocci were the causative agents in most (21/41; 51%) infections, with Streptococcus canis associated with 24% of infections. Gram-negative organisms were detected in 9 of the 41 (22%) dogs. Infection with Bartonella spp was detected in 6 of 31 (19%) dogs with negative results for microbial growth on blood culture. Aortic valve involvement and congestive heart failure were more frequent in dogs with endocarditis from Bartonella spp infection, and those dogs were more likely to be afebrile. Infection with Bartonella spp was negatively correlated with survival. Mitral valve involvement and polyarthritis were more frequent in dogs with streptococcal endocarditis. CONCLUSIONS AND CLINICAL RELEVANCE: Streptococci were the most common cause of IE and were more likely to infect the mitral valve and be associated with polyarthritis. Dogs with IE secondary to Bartonella spp infection were often afebrile, more likely to develop congestive heart failure, rarely had mitral valve involvement, and had shorter survival times.     

Purification and characterization of a chimeric Cry1F delta-endotoxin expressed in transgenic cotton plants

Cotton plants were genetically modified through the introduction of a synthetic gene that encodes a Bacillus thuringiensis insecticidal protoxin referred to as Cry1F(synpro). This protoxin is a chimeric, full-length delta-endotoxin of 130 kDa, comprised of the core toxin of Cry1Fa2 protein and parts of the nontoxic portions of Cry1Ca3 and Cry1Ab1 proteins, all of which originated from Bacillus thuringiensis. The Cry1F(synpro) expressed in cotton plants confers resistance to lepidopteran pests. The current study was conducted to characterize the Cry1F(synpro) protein expressed in the transgenic cotton event 281-24-236. Results showed that the full-length Cry1F(synpro) produced in the transgenic cotton plants was sensitive to the host cell protease cleavage, resulting in a truncated, biologically active form (core toxin) with an apparent molecular mass of 65 kDa. This truncated toxin was purified by immunoaffinity chromatography from the cotton leaf extract. N-terminal sequencing, peptide mass fingerprinting by MALDI-TOF MS, and internal peptide sequencing by MS/MS confirmed the identity of the truncated core toxin of Cry1F. The mechanism of truncation was explored with Cry1F(synpro) derived from a recombinant Pseudomonas fluorescens. The transgenic cotton-produced Cry1F showed equivalent insecticidal activity to that of Pseudomonas fluorescens-derived Cry1F.