Population size of Clavibacter michiganensis subsp. sepedonicus in potato cv Russet Burbank and plant response as affected by drought were assessed in a greenhouse experiment. Water deficit stress and no stress treatments, and inoculum densities of 0 or 2 X 10��� cfu C. m. sepedonicus/seed piece were arranged factorially. Stem populations of C. m. sepedonicus were significantly lower in the water deficit stress treatment compared to the non-stressed treatment at every sampling date in both experiments. In seven of the eight harvests the number of C. m. sepedonicus cells/g of stem tissue for the water deficit stress treated, infected plants was a factor of 10 lower than the non-stressed treatment. Foliar symptoms of bacterial ring rot were not observed, but symptoms developed in tubers. Compared to the noninoculated control inoculum reduced aerial biomass from 12 to 21% and tuber yield from 15 to 38% in samples taken four times after the drought was terminated. Reduction of these same variables due to water deficit stress ranged from 17 to 21% and 15 to 41%, respectively, compared to the non-stressed control. Therefore, both water deficit stress and C. m. sepedonicus had similar effects on growth and tuber yield of potato. / Graduation date: 1995

Les substances perturbatrices du système endocrinien sont des substances qui, de par leur capacité à induire des changements hormonaux chez les organismes vivants, génèrent des préoccupations dans le domaine de la qualité des eaux et, par extension, dans le domaine du traitement des effluents aqueux. Particulièrement, ce projet de recherche s’est attardé sur l’élimination des perturbateurs endocriniens phénoliques nonylphénol (NP), bisphénol A (BPA) et triclosan (TCS) en solution aqueuse à l’aide de la laccase (E.C. 1.10.3.2) sécrétée par la souche fongique Coriolopsis polyzona. Cette oxydase est une métalloprotéine pouvant catalyser l’oxydation d’une vaste gamme de substances phénoliques. En premier lieu, l’impact du pH et de la température sur l’élimination de ces composés à l’aide de la laccase libre en utilisant un design factoriel. L’oxydation de ces composés produit des oligomères (dimère à pentamère) via le couplage des radicaux phénoxy produits par l’action de la laccase. Il s’avère que les substances produites suite à l’oxydation du NP et du BPA par la laccase ont perdu leurs similitudes structurales avec l’estrogène. Ainsi, l’élimination de l’activité estrogénique de ces substances est directement liée à la transformation des composés. Finalement, l’utilisation d’ABTS comme médiateur a permis d’augmenter le taux d’oxydation enzymatique de ces composés chimiques. Puis, de façon à augmenter la possibilité d’utilisation de la laccase dans des biotechnologies environnementales, cette enzyme a été immobilisée sur un support siliceux et via la réticulation d’agrégats. L’impact des conditions d’immobilisation sur l’activité enzymatique, la stabilité du catalyseur et les propriété biocatalytiques apparentes a été déterminé pour différentes stratégies d’immobilisation. Globalement, l’immobilisation génère un biocatalyseur stable vis-à-vis les dénaturations chimique, physique et biologique. Particulièrement, l’immobilisation sur un support solide produit un biocatalyseur facile à utiliser ayant une faible activité massique et des propriétés cinétiques moindres que celle de l’enzyme libre. La formation de CLEAs de laccase a permis d’obtenir une activité massique élevée et des propriétés cinétiques supérieures à celle de l’enzyme soluble. Ces biocatalyseurs solides ont étés utilisés pour éliminer en continu le NP, BPA et TCS dans différents types de bioréacteur. Le biocatalyseur sur silice a été utilisé pour éliminer ces substances dans un réacteur garni, tandis que les CLEAs ont été utilisés dans un réacteur à lit fluidisé et un réacteur à perfusion développé au cours de ce projet. Ces différentes configurations de bioréacteur ont permis d’éliminer efficacement ces différents perturbateurs endocriniens. Globalement, les différents résultats obtenus, à l’échelle de laboratoire, au cours de ce projet de recherche démontrent que la laccase et particulièrement les biocatalyseurs formés via les différentes stratégies d’immobilisation testées représentent des approches extrêmement prometteuses pour le développement de biotechnologies environnementales vouées à l’élimination des perturbateurs endocriniens phénoliques.

Wood inhabiting fungi oposes a great problem for preservation of wooden surfaces everywhere, being the main problem of economic losses of wooden products. A reference collection consisting of 9 different genus constituting of 21 different strains of wood-inhabiting fungi was used for identification of unknown species of mould and blue stain fungi on wood. The fungus DNA from the samples was isolated from malt extract agar. PCR (Polymerase Chain Reaction) was conducted on rDNA ITS1 and ITS2 regions for amplification of the DNA. The 21 samples were collected to a reference collection for identification of unknown species of fungi on wooden field samples using PCR and T-RFLP (Terminal Restriction Fragment Length Polymorphism). PCR-based methods, sequencing and T-RFLP were proven to be simple and accurate methods for detection and identification of fungi in their early stage.

Biocatalysts are important tools for harnessing the potential of wood fibres since they can perform specific reactions with low environmental impact. Challenges to bioconversion technologies as applied to wood fibres include low accessibility of plant cell wall polymers and the heterogeneity of plant cell walls, which makes it difficult to predict conversion efficiencies. White-rot fungi are among the most efficient degraders of plant fibre (lignocellulose), capable of degrading cellulose, hemicellulose and lignin. Phanerochaete carnosa is a white-rot fungus that, in contrast to many white-rot fungi that have been studied to date, was isolated almost exclusively from fallen coniferous trees (softwood). While several studies describe the lignocellulolytic activity of the hardwood-degrading, model white-rot fungus Phanerochaete chrysosporium, the lignocellulolytic activity of P. carnosa has not been investigated. An underlying hypothesis of this thesis is that P. carnosa encodes enzymes that are particularly well suited for processing softwood fibre, which is an especially recalcitrant feedstock, though a major resource for Canada. Moreover, given the phylogenetic similarity of P. carnosa and P. chrysosporium, it is anticipated that the identification of pertinent enzymes for softwood degradation can be more easily conducted. In particular, this project describes the characterization of P. carnosa in terms of the growth conditions that support lignocellulolytic activity, the effect of enzymes secreted by P. carnosa on the chemistry of softwood feedstocks, and the characterization of the corresponding secretome using proteomic techniques. Through this study, cultivation methods for P. carnosa were established and biochemical assays for protein activity and quantification were developed. Analytical methods, including FTIR and ToF-SIMS were used to characterize wood samples at advancing stages of decay, and revealed preferential degradation of lignin in the early stages of growth on all softwoods analyzed. Finally, an in depth proteomic analysis of the proteins secreted by P. carnosa on spruce and cellulose established that similar sets of enzyme activities are elicited by P. carnosa grown on different lignocellulosic substrates, albeit to different expression levels.

Biocatalysts are important tools for harnessing the potential of wood fibres since they can perform specific reactions with low environmental impact. Challenges to bioconversion technologies as applied to wood fibres include low accessibility of plant cell wall polymers and the heterogeneity of plant cell walls, which makes it difficult to predict conversion efficiencies. White-rot fungi are among the most efficient degraders of plant fibre (lignocellulose), capable of degrading cellulose, hemicellulose and lignin. Phanerochaete carnosa is a white-rot fungus that, in contrast to many white-rot fungi that have been studied to date, was isolated almost exclusively from fallen coniferous trees (softwood). While several studies describe the lignocellulolytic activity of the hardwood-degrading, model white-rot fungus Phanerochaete chrysosporium, the lignocellulolytic activity of P. carnosa has not been investigated. An underlying hypothesis of this thesis is that P. carnosa encodes enzymes that are particularly well suited for processing softwood fibre, which is an especially recalcitrant feedstock, though a major resource for Canada. Moreover, given the phylogenetic similarity of P. carnosa and P. chrysosporium, it is anticipated that the identification of pertinent enzymes for softwood degradation can be more easily conducted. In particular, this project describes the characterization of P. carnosa in terms of the growth conditions that support lignocellulolytic activity, the effect of enzymes secreted by P. carnosa on the chemistry of softwood feedstocks, and the characterization of the corresponding secretome using proteomic techniques. Through this study, cultivation methods for P. carnosa were established and biochemical assays for protein activity and quantification were developed. Analytical methods, including FTIR and ToF-SIMS were used to characterize wood samples at advancing stages of decay, and revealed preferential degradation of lignin in the early stages of growth on all softwoods analyzed. Finally, an in depth proteomic analysis of the proteins secreted by P. carnosa on spruce and cellulose established that similar sets of enzyme activities are elicited by P. carnosa grown on different lignocellulosic substrates, albeit to different expression levels.

Serpula lacrymans infestation has become an increasingly common problem, and is usually perceived as a tip of an iceberg. During the 21st century there has been a perceived increase of damage caused by serpula lacrymans, at AB Mats Fransson Saneringstjänst – Anticimex in the county of Kronoberg. A similar increase has also been noted by employees at the offices in Kalmar, Karlstad, Piteå, Stockholm, Malmö, Söderhamn, Halmstad and Visby. The methods used to collect data for the project has been interviews with a number, for the project, relevant key persons, such as analysis engineers at Trygghansa and Anticimex, as well as personnel at the botanical institution at Gothenburg University and the Botaniska Analysgruppen in Gothenburg, further statistics from SMHI and analyses of reported instances of infestations have been used. The majority of the people interviewed believe that the increase is caused by renovations of old houses, higher precipitation during the summer months, as well as a moister climate and warmer winters. The latter can also be gleaned from statistics from SMHI concerning temperature, precipitation, and relative humidity. Analysed damage reports show that the most common cause for the infestation is ground moisture, even when combined wooden materials. Older houses that where built around 1900 are the ones most frequently infested with serpula lacrymans. The part of the building most frequently infested is the foundation, where cellars and suspended foundation are the most common types to be infested. An infestation is usually detected during the months of August and September. / Hussvampangrepp hos fastighetsägare har blivit ett allt mer vanligt problem och syns oftast bara som toppen av ett isberg. På AB Mats Franssons Saneringstjänst Anticimex i Kronobergs län, har det under 2000-talet märkts av en ökning av hussvampsskador. Vilket även de anställda vid kontoren i Kalmar, Karlstad, Piteå, Stockholm, Malmö, Söderhamn, Halmstad och Visby har gjort. Metoder för faktainsamling under arbetets gång har varit intervjuer med ett antal, för projektet relevanta nyckelpersoner så som skadeingenjörer vid Trygghansa och Anticimex, samt personal vid botaniska institutionen vid Göteborgs universitet och Botaniska Analysgruppen i Göteborg. Vidare har statistik från SMHI använts och undersökning av skaderegister har genomförts. Majoriteten av intervjupersonerna tror att ökningen beror på renovering av äldre hus, högre nederbörd under sommarmånaderna, fuktigare klimat och mildare vintrar. Det sistnämnda kan även bekräftas utifrån statistik från SMHI gällande temperatur, nederbörd och relativ fuktighet. Undersökta skaderapporter visar att den vanligaste uppkomsten till skadan är markfukt, även kombinerad med trämaterial. Äldre hus som är byggda runt 1900 angrips oftast av hussvamp. Den konstruktion som angrips mest är grundkonstruktionen där källare och torpargrund dominerar. En skada påträffas i regel under augusti och september månad.

The uplink load for the scheduling of Enhanced-Uplink (E-UL) channels determine the achievable data rate for Wideband Code Division Multiple Access (WCDMA) systems, therefore its accurate measurement carries a prime significance. The uplink load also known as Rise-over-Thermal (RoT), which is the quotient of the Received Total Wideband Power (RTWP) and the Thermal Noise Power floor. It is a major parameter which is calculated at each Transmission Time Interval (TTI) for maintaining cell coverage and stability. The RoT algorithm for evaluation of uplink load is considered as a complex and resource demanding among several Radio Resource Management (RRM) algorithms running in a radio system. The main focus of this thesis is to study RoT algorithm presently deployed in radio units and its possible optimization by reducing complexity of the algorithm in terms of memory usage and processing power. The calculation of RoT comprises three main blocks a Kalman filter, a noise floor estimator and the RoT computation. After analyzing the complexity of each block it has been established that the noise floor estimator block is consuming most of the processing power producing peak processor load since it involves many complex floating point calculations. However, the other blocks do not affect the processing load significantly. It was also observed that some block updates can be reduced in order to decrease the average load on the processor. Three techniques are proposed for reducing the complexity of the RoT algorithm, two for the reduction of peak load and one for the reduction of average load. For reducing the peak load, an interpolation approach is used instead of performing transcendental mathematical calculations. Also, the calculations involving noise floor estimation are extended over several TTIs by keeping in view that the estimation is not time critical. For the reduction of average load, the update rate for the Kalman Filter block is reduced. Based on these optimization steps, a modified algorithm for RoT computation with reduced complexity is proposed. The proposed changes are tested by means of MATLAB simulations demonstrating the improved performance with consistency in the output results. Finally, an arithmetic operation count is done using the hardware manual of Power PC (PPC405) used in Platform 4, which gives a rough estimate of decrease in the percentage of calculations after optimization. / saabairshad@gmail.com

Darbo objektas - įvairaus amžiaus centrinio puvinio pažeisti eglės medžiai, kurie auga skirtinguose našumo rajonuose. Darbo tikslas – centrinio puvinio paplitimo tipinėse paprastosios eglės augavietėse (Nc, Nd, Lb, Lc, Ld) vertinimo garsiniu tomografu ARBOTOM 3D galimybių tyrimas. Darbo metodai – duomenys apie puvinio išplitimą rinkti naudojant garsinį tomografą Arbotom 3D. Surinkti duomenys apdoroti naudojant MS Excel, Statistica ir Arbotom programas. Atliekant tyrimą buvo naudoti tokie bendrieji metodai: dokumentų analizės, duomenų grupavimo, modeliavimo, loginis, palyginimo, apibendrinimo. Rezultatai – Duomenys buvo renkami 4 gamtiniuose – našumo rajonuose.Tyrimo metu pamatuota 3269 medžiai iš kurių 703 nuskenuota garsiniu tomografu. Darbo metu nustatyta, kad vaizdus, gautus garsinio tomografo Arbotom 3D pagalba, galima apdoroti su 85,44 proc patikimumu. Geriausiai puvinio buvimo stiebe faktą nusako ne absoliutus garso sklidimo greitis medienoje, bet minimalaus ir maksimalaus greičių sklidimo skirtumo santykis su mažiausiu sklidimo greičiu, bei stiebo skersmeniu 1.3 m aukštyje. Modeliuojant puvinio buvimo tikimybę Lietuvos mastu, modelyje tikslinga papildomai naudoti medžių amžių bei našumo rajoną. Didžiausias puvinio pažeistų medžių procentas buvo nustatytas IV (38,7 proc.) ir I ( 37,8 proc) Krafto klasės medžiams, II ir III klasėje pažeistų medžių buvo atitinkamai 28 proc. ir 34 proc. Tyrimų metu nustatyta, kad Lc ir Nc augavietėse puvinio pažeistų medžių dalis yra... [toliau žr. visą tekstą] / Subject of work –Norway spruce trees of various age class, that were damage by core rot in respect to regions of natural forest productivity. Aim of work – to investigate the possibilities of ARBOTOM 3D to identify the spread of core rot in Norway spruce regarding to forest type sites (Nc, Nd, Lb, Lc, Ld). Methods of work – material respecting rot spread were collected using tomography ARBOTOM 3D. Collected data was analyzed using Statistica, Excell and Arbotom software applications The following common scientific methods were used in this research: data analyzes, data grouping, modelling logic, comparison, syntheses. Results of work – The data of the research was collected in 4 State forests enterprises in respect to regions of natural forest productivity. In this study, 27 spruce stands of different age were choosen using random selection. The trees parameters were estimated for 3269 spruces, 703 out of estimated trees were scanned using acoustic tomography to determine the spread of rot inside stems. The reliability of 85.55 percentages was reached using ARBOTOM. The results of research revealed, that the most success approach to identify the rot in a stem was the ratio difference between maximal and minimas velocity to minimum velocity also stem diameter in 1.3 meter. Regarding to rot spread modelling in Lithuania it is advisable to use the ages of trees and regions of natural forest productivity additionally. The data of the research revealed that the most rotted... [to full text]

Colleotrichum graminicola is the causal agent of anthracnose stalk rot, and is one of the most common and aggressive pathogens of maize. The goal of my Ph.D. project was to contribute to a better understanding of the biology of the interaction between C. graminicola and its host. C. graminicola produces two type of asexual spores: one is produced on the surface of infected tissues and is thought to be involved in the spread of the disease in the field. The second type of spore, oval in shape, is produced inside the infected plant tissues, and was believed to be involved in the movement of the pathogen inside the plant tissues via the vascular system. I tested this hypothesis with both cytological and molecular approaches. I used strains of C. graminicola expressing green fluorescent proteins (GFP) to inoculate wounded plants, and followed the development of the pathogen over time. This study revealed that C. graminicola is not a vascular pathogen. C. graminicola primarily moved through the rind and vascular fibers. Oval spores were produced in colonized parenchyma cells and remained dormant, and did not appear to be involved in the movement of the pathogen, at least during the early stages of the disease development. I also studied pathogen ingress in the absence of a wound. I inoculated unwounded plants with the GFP expressing strains. C. graminicola efficiently colonized the epidermis and, given enough time, penetrated and colonized the deeper parenchyma tissues, after first moving through the fibers. To further test the role of sporulation in colonization of maize tissues, I used targeted mutagenesis to disrupt a major gene known to regulate sporulation and vegetative growth in several other fungi. The gene Cgg1, orthologue of the A. nidulans fadA, was disrupted using the split marker method. The Cgg1 mutants were less pathogenic than the wildtype to wounded plants. This was associated with an apparent increase in production of spores and primary infection hyphae. This suggests that Cgg1 signaling pathway plays a role in maximizing colonization of host tissues, and that this involves negative regulation of sporulation and primary hyphae production in planta.

Multiple species of Colletotrichum can cause bitter rot disease of apple, but the identities and relative representation of the species causing the disease in Kentucky are unknown. A total of 475 Colletotrichum isolates were collected from diseased apples in 25 counties and characterized both morphologically and by using various molecular approaches. Four morphotypes corresponded to reported descriptions of bitter rot species. Morphotype 1, distinguished by the production of a pink color on potato dextrose agar (PDA), orange conidial masses, and fusiform spores, was consistent with C. acutatum. Morphotype 2, which produced gray or white mycelial colonies with orange conidial masses and fusiform spores, was also similar to C. acutatum. Morphotype 3 had abundant gray mycelium and rounded spores and was identical to C. gloeosporioides. Morphotype 4 produced ascospores and resembled Glomerella cingulata. Species-specific polymerase chain reaction (PCR) indicated that both Morphotype 1 and Morphotype 2 belonged to the C. acutatum species complex, whereas Morphotype 3 and Morphotype 4 corresponded to the C. gloeosporioides complex. Multigene sequence analyses revealed that sample isolates belonged to several newly erected species within these species complexes. Morphotype 1 was identified as C. fioriniae, which resides within the C. acutatum species complex. Morphotype 2 was identified as C. nymphaeae, which is also a species within the C. acutatum species complex. Some isolates of Morphotype 3 were identified as C. siamense and some as C. theobromicola; both species are grouped within the C. gloeosporioides species complex. Morphotype 4 was identified as C. fructicola, which is also placed within the C. gloeosporioides species complex. C. fioriniae was the most common species causing bitter rot in Kentucky, comprising more than 70% of the isolates. Molecular fingerprinting using random amplified polymorphic DNA (RAPD) suggested that isolates within C. fioriniae belonged to a relatively homogeneous population, while isolates within C. siamense, C. theobromicola and C. fructicola were more diverse. Infectivity tests on detached fruit showed that C. gloeosporioides species-complex isolates were more aggressive than isolates in the C. acutatum species complex. However, isolates within the C. acutatum species complex produced more spores on lesions compared to isolates within the C. gloeosporioides species complex. Aggressiveness varied among individual species within a species complex. C. siamense was the most aggressive species identified in this study. Within the C. acutatum species complex, C. fioriniae was more aggressive than C. nymphaeae, causing larger, deeper lesions. Apple cultivar did not have significant effect on lesion development. However, Colletotrichum species produced more spores on Red Stayman Winesap than on Golden Delicious. Fungicide sensitivity tests revealed that the C. acutatum species complex was more tolerant to thiophanate-methyl, myclobutanil, trifloxystrobin, and captan compared to the C. gloeosporioides species complex. The study also revealed that mycelial growth of C. siamense was more sensitive to tested fungicides compared to C. fructicola and C. theobromicola. These research findings emphasize the importance of accurate identification of Colletotrichum species within each species complex, since they exhibit differences in pathogenicity and fungicide sensitivity.