The role of interleukin-8 (IL-8) as a neutrophil chemoattractant in bovine pneumonic pasteurellosis was investigated by characterizing: (1) the expression of IL-8 in the lesions of pneumonic pasteurellosis, (2) the ' in vitro' and 'in vivo' effects of recombinant bovine IL-8 on neutrophil chemotaxis, and (3) the importance of IL-8 as a neutrophil chemoattractant in this disease. The expression of IL-8 in bovine pneumonic pasteurellosis was assessed by Northern analysis, 'in situ' hybridization and enzyme-linked immunosorbent assay. The expression of IL-8 mRNA was elevated dramatically in lesional lung compared to non-lesional lung, viral pneumonia, and normal lung. 'In situ' hybridization revealed intense IL-8 mRNA expression in alveolar macrophages and neutrophils, and milder expression in several other cell types. Bronchoalveolar lavage (BAL) fluid from lesional lung contained 16.06 ± 4.00 ng/ml IL-8, but lower levels were present in non-lesional lung, viral pneumonia, and normal lung (mean ± SEM). Recombinant bovine IL-8 (rbIL-8) was produced using a pGEX expression system. The rbIL-8 induced <i>in vitro</i> chemotaxis and shape change of bovine neutrophils at doses as low as 6.3 ng/ml. After injection of 1.0 ng to 3.3 <math> <f> <g>m</g></f> </math>g of rbIL-8 into bovine skin, neutrophils marginated in vessels within 15 minutes and infiltrated the dermis by 1 hour after injection. These results demonstrate that bovine IL-8 is a neutrophil chemoattractant 'in vitro ' and 'in vivo', at levels equivalent to those present in pneumonic pasteurellosis. An ovine model of pneumonic pasteurellosis was developed to ascertain the effects of <i> in vivo</i> neutralization of IL-8 on the development of disease. At 0, 3, 8 and 20 hours after bacterial infection (p.i.), BAL fluid samples contained 6.5 ± 2.4, 110 ± 48, 554 ± 118, and 507 ± 70 ng/ml IL-8, respectively. Neutrophil infiltration was mild at 3 hours p.i. but progressively more intense at 8 and 20 hours p.i. Lambs were treated intravenously with up to 80 mg of an IL-8-neutralizing antibody prior to bacterial challenge. The antibody treatment failed to completely neutralize IL-8 activity, probably because the levels of IL-8 in the lung were unexpectedly high. The contribution of IL-8 to the neutrophil chemotactic activity of BAL fluid from cattle and lambs with pneumonic pasteurellosis was assessed. Pre-treatment of pneumonic BAL fluid samples with a neutralizing antibody to IL-8, compared to pretreatment with a control antibody, reduced the 'in vitro' neutrophil chemotactic activity significantly, by 15-63% in 9/10 samples. An extract of pneumonic bovine lung induced vigorous neutrophil infiltration following injection into bovine skin, and depletion of IL-8 from the extract reduced this neutrophil influx by 60%. These data indicate that IL-8 is an important neutrophil chemoattractant in both early and well-developed lesions of pneumonic pasteurellosis, but that mediators with actions redundant to those of IL-8 must also be present at these times.

Imidacloprid, a neonicotinoid insecticide, is commonly applied on eastern hemlock to reduce populations of Hemlock woolly adelgid (HWA). A large number of other herbivorous and transient insects also are associated with eastern hemlock. These herbivorous insects may acquire imidacloprid through feeding on treated plants. Predatory insects may acquire imidacloprid when they feed on insecticide-contaminated prey. To investigate this phenomenon, a study was conducted at Indian Boundary Campground, Cherokee National Forest, 2005-2007. This study was conducted to: 1) ascertain the effect of imidacloprid used against HWA on the predatory guild associated with eastern hemlock, 2) determine seasonal abundance of the predatory guild on eastern hemlock, and 3) assess influence of vertical stratification on spiders and other predators.During this study, 4,917 predators representing 75 families and 10 orders were collected. Spiders were the most dominant predator group, and the most abundant spider families were Mimetidae (1,038), Salticidae (736), Araneidae (733), Gnaphosidae (517), Philodromidae (330), Theridiidae (168), Tetragnathidae (161) and Thomisidae (142). The most abundant insect predator families were Vespidae (132), Ichneumonidae (50), Braconidae (31), Pentatomidae (25), Reduviidae (24), Coccinellidae (15), and Elateridae (15). Predator densities were not significantly different between pesticide application times (Fall and Spring). In both years, predator densities in control treatments and horticultural oil treatments were significantly (p<0.05) greater than those in imidacloprid treatments. However, predator densities were not significantly (p<0.05) different among soil drench, soil injection, and tree injection treatments or between control and horticultural oil treatments. Predator densities were at least 1.5-3X greater in the imidacloprid-treated plots in 2007 than in 2006, possibly suggesting a rebound in predator densities 1-1½ years after treatment.Predator densities were significantly (p<0.05) greater in the top and middle canopy than in the lower canopy. Imidacloprid concentration level declined progressively from the bottom stratum to the top stratum of the tree canopy. Highest levels were observed in the bottom stratum which shows that higher concentrations of imidacloprid lead to lower numbers of predators and lower concentrations of imidacloprid lead to higher numbers of predators.

Thesis (Ph. D.)--University of Oregon, 2001. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 96-103). Also available for download via the World Wide Web; free to University of Oregon users.

Inaug.-Diss.--Universität Erlangen-Nürnberg, Erlangen. / Vita.

Thesis (M.A.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 54-58).

(+)-Pisatin, ([+]-[6aR,11aR]-6a-hydroxy-3-methoxy-8,9-methylenedioxypterocarpan) is the major phytoalexin of the garden pea (Pisum sativum L.). Despite being the first phytoalexin to be chemically characterized, its biosynthesis remains to be fully elucidated. RNA-mediated genetic interference (RNAi) was used to gain further insights into the (+)-pisatin biosynthetic pathway. The expression of three genes, isoflavone reductase (IFR) catalyzing the reduction of 7,2'-dihydroxy-4',5'-methylenedioxyisoflavone to (-)-sophorol, sophorol reductase (SOR) involved in reducing (-)-sophorol to (-)-7,2'-dihydroxy-4',5'-methylenedioxyisoflavanol and hydroxymaackiain-3-O methyltransferase (HMM) involved in methylation of (+)-6a-hydroxymaackiain to (+)-pisatin was silenced. The genes are transcriptionally co-regulated during (+)-pisatin biosynthesis, with the IFR and SOR proposed to function upstream of the HMM gene.Hairy roots expressing the HMM RNAi construct, deficient in (+)-pisatin biosynthesis were identified. However, these did not accumulate (+)-6a-hydroxymaackiain, precursor to (+)-pisatin. Instead they accumulated 2,7,4'-trihydroxyisoflavanone, daidzein, liquiritigenin and isoformononetin. The amino acid sequence of HMM is very similar to that of another methyltransferase, hydroxyisoflavanone-4'-O-methyltransferase (HI4MOT), found in most legumes. HI4?MOT catalyzes the methylation of 2,7,4'-trihydroxyisoflavanone (THI) to 2,7-dihydroxy-4'-methoxyisoflavanone, one of the earliest enzymatic steps in isoflavonoid biosynthesis. In pea, HI4OMT may be the same enzyme as "HMM" catalyzing the methylation of both THI and (+)-6a-hydroxymaackiain. Preventing the methylation of THI could divert pea intermediates to the production of daidzein and isoformononetin instead of (+)-pisatin.None of the transgenic hairy roots expressing the IFR RNAi construct were totally deficient in (+)-pisatin biosynthesis. However, all produced reduced amounts of (+)-pisatin, with one culture accumulating 7,2'-dihydroxy-4',5'-methylenedioxyisoflavone, the substrate for IFR. Hairy roots expressing the SOR RNAi construct deficient in (+)-pisatin biosynthesis were identified. These accumulated (-)-sophorol, the substrate for SOR. These data provide evidence for the involvement of these genes and the intermediates with (-)-optical activity in (+)-pisatin biosynthesis.The elicitation of the biosynthesis of secondary metabolites in plant cell and tissue cultures by electric current was explored. Electric current was demonstrated to elicit the biosynthesis of secondary metabolites in pea hairy and intact roots, seedling, root and cell suspension cultures of various plant species. Electric current has potential for use as an elicitor of secondary metabolites in basic and commercial research ventures.

The nature of host susceptibility to phytopathogenic parasites, especially the obligates, remains one of the major problems in plant pathology even though it has been investigated extensively from the early part of the present century until the late thirties. Studies on the genetics of the pathogens and breeding for resistant varieties have predominated since that time. There is at present a revival of interest in the physiology of disease resistance. [...]

Verticillium wilt is often the cause of serious losses in potatoes in Eastern Canada and Northern United States. It is of minor importance in field tomatoes except in California and Utah. The disease is not uncommon in greenhouse tomatoes in North America and in Europe. [...]

Hay is the most important crop in Quebec. According to the annual report of the Quebec Bureau of Statistics for 1961, of a total cultivated area of 7,864,176 acres in Quebec, 3,458,000 acres were in hay. The value of the hay crop in 1961 was 55.8 percent of the value of all field crops in the province. Since alfalfa, birdsfoot trefoil, red, alsike, and ladino clovers are cominant in this hay crop, their agricultural importance is apparent. This, together with the fact that some of these forage legumes, mainly red clover and alfalfa, are the most common rotation crops, led to the choice of these plants for study.

The pathology of our native larch, Larix laricina (Du Roi) Koch, has never been carefully investigated in the province of Quebec. One of the explanations of this apparent lack of interest in diseases of this tree species is the very important infestation by the larch sawfly (Pristiphora Erichsonii Htg.), which, at the beginning of the present century, greatly reduced the best stands of larch in Northeast America. Usually the Eastern larch, commonly called tamarack, provides a hard, heavy and non-porous wood of high technical value. Its resistance to decay outweighs any other conifer of Eastern and Central Canada (2).