The effect of lignin content and lignin modification on Norway spruce wood properties and decay resistance

Three different Norway spruce cutting clones growing in three environments with different soil and climatic conditions were studied. The purpose was to follow variation in the radial growth rate, wood properties and lignin content and to modify wood lignin with a natural monolignol, coniferyl alcohol, by making use of inherent wood peroxidases. In addition, the incorporation of chlorinated anilines into lignin was studied with synthetic model compounds and synthetic lignin preparations to show whether unnatural compounds originating from pesticides could be bound in the lignin polymer. The lignin content of heartwood, sapwood and earlywood was determined by applying Fourier transform infrared (FTIR) spectroscopy and a principal component regression (PCR) technique. Wood blocks were treated with coniferyl alcohol by using a vacuum impregnation method. The effect of impregnation was assessed by FTIR and by a fungal decay test. Trees from a fertile site showed the highest growth rate and sapwood lignin content and the lowest latewood proportion, weight density and modulus of rupture (MOR). Trees from a medium fertile site had the lowest growth rate and the highest latewood proportion, weight density, modulus of elasticity (MOE) and MOR. The most rapidly growing clone showed the lowest latewood proportion, weight density, MOE and MOR. The slowest growing clone had the lowest sapwood lignin content and the highest latewood proportion, weight density, MOE and MOR. Differences between the sites and clones were small, while fairly large variation was found between the individual trees and growing seasons. The cutting clones maintained clone-dependent wood properties in the different growing sites although variation between trees was high and climatic factors affected growth. The coniferyl alcohol impregnation increased the content of different lignin-type phenolic compounds in the wood as well as wood decay resistance against a white-rot fungus, Coriolus versicolor. During the synthetic lignin preparation 3,4-dichloroaniline became bound by a benzylamine bond to β-O-4 structures in the polymer and it could not be released by mild acid hydrolysis. The natural monolignol, coniferyl alcohol, and chlorinated anilines could be incorporated into the lignin polymer in vivo and in vitro, respectively.

Decay resistance of thermally-modified Eucalyptus grandis wood at 140 degrees C, 160 degrees C, 180 degrees C, 200 degrees C and 220 degrees C

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical properties and decay resistance of eucalyptus grandis wood from steamed logs

The objective of this study was evaluate the effect of the log steaming on the chemical properties and decay resistance of Eucalyptus grandis wood. Logs with diameter between 20 and 22 cm were studied. Half of logs were kept in its on original condition, and the other half was steamed at 90°C for 13 hours. The holocellulosc, Klason lignin, total extractives content and the weight loss caused by the decay fungus Pycnoporus sanguineous were characterized. The results showed that the log steaming of E. grandis wood cause: (l)a significantly decreased in holocellulose content; (2) an increase of 4.8% and 4.4% in total extractives and lignin content, respectively; and (3) a decrease in its durability against the decay fungus P. sanguineus in order of 13.03%. Copyright © (2012) by WCTE 2012 Committee.

Effect of surface-applied treatments on the above-ground performance of simulated timber joinery

We examined the effect of surface-applied treatments on the above-ground decay resistance of the tenon of mortice-and-tenon timber joints designed to simulate joinery that is exposed to the weather. Joints made from untreated radiata pine, Douglas-fir, brush box, spotted gum and copper-chrome-arsenic (CCA) treated radiata pine were exposed to the weather for 9 y on above-ground racks at five sites throughout eastern Australia. Results indicate (1) a poorly maintained external paint film generally accelerated decay, (2) a brush coat of water-repellent preservative inside the joints often extended serviceability (in some cases by a factor of up to seven times that of untreated joints) and (3) the level of protection provided by a coat of primer applied inside the joint varied and in most cases was not as effective as the water-repellent preservative treatment.

Efeito da termorretificação nas propriedades físicas, mecânicas e na resistência a fungos deterioradores da madeira de Eucalyptus grandis Hill ex Maiden

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Behavior of the brown-rot fungus Gloeophyllum trabeum on thermally-modified Eucalyptus grandis wood

In this study, we aimed evaluate the behavior of the brown-rot fungus Gloeophylum trabeum and white-rot fungus Pycnoporus sanguineus on thermally-modified Eucalyptus grandis wood. To this end, boards from five-year-eleven-month-old E. grandis trees, taken from the Duratex-SA company stock, were thermally-modified between 180 ºC and 220 ºC in the Laboratory of Wood Drying and Preservation at Universidade Estadual Paulista - UNESP, Botucatu, Sao Paulo state Brazil. Samples of each treatment were tested according to the ASTM D-2017 (2008) technical norm. The accelerated decay caused by the brown-rot fungus G. trabeum was compared with the decay caused by the white-rot fungus P. sanguineus, studied by Calonego et al. (2010). The results showed that (1) brown-rot fungus caused greater decay than white-rot fungus; and (2) the increase in temperature from 180 to 220 ºC caused reductions between 28.2% and 70.0% in the weight loss of E. grandis samples incubated with G. trabeum.

Resistance Mechanisms of Non-Hodgkin Lymphomas against Rituximab Treatment

Rituximab, a monoclonal antibody against B-cell specific CD20 antigen, is used for the treatment of non-Hodgkin lymphomas (NHL) and chronic lymphatic leukemia. In combination with chemotherapeutics rituximab has remarkably improved the outcome of NHL patients, but a vast variation in the lengths of remissions remains and the outcome of individual patients is difficult to predict. This thesis has searched for an explanation for this by studying the effector mechanisms of rituximab and by comparing gene expression in lymphoma tissue samples of patients with long- and short-term survival. This work demonstrated that activation of complement (C) system is in vitro more efficient effector mechanism of rituximab than cellular mechanisms or apoptosis. Activation of the C system was also shown in vivo during rituximab treatment. However, intravenously administered rituximab could not enter the cerebrospinal fluid, and neither C activation nor removal of lymphoma cells was observed in central nervous system. In vitro cytotoxicity assays showed that rituximab-induced cell killing could be markedly improved with simultaneous neutralization of the C regulatory proteins CD46 (Membrane cofactor protein), CD55 (Decay-accelerating factor), and CD59 (protectin). In a retrospective study of follicular lymphoma (FL) patients, low lymphoma tissue mRNA expressions of CD59 and CD55 were associated with a good prognosis and in a progressive flow cytometry study high expression of CD20 relative to CD55 was correlated to a longer progression free survival. Gene expression profile analysis revealed that expression of certain often cell cycle, signal transduction or immune response related genes correlate with clinical outcome of FL patients. Emphasizing the role of tumor microenvironment the best differentiating genes Smad1 and EphA1 were demonstrated to be mainly expressed in the non-malignant cells of tumors. In conclusion, this thesis shows that activation of the C system is a clinically important effector mechanism of rituximab and that microenvironment factor in tumors and expression of C regulatory proteins affect markedly the efficacy of immunochemotherapy. This data can be used to identify more accurately the patients for whom immunochemotherapy is given. It may also be beneficial in development of rituximab-containing and other monoclonal antibody therapies against cancer.

Measuring the electronic decay constant of alkanedithiols by electrochemical impedance spectroscopy

Several methods have been used for the measurement of the electronic decay constant (beta) of organic molecules. However, each of them has some disadvantages. For the first time, electrochemical impedance spectroscopy (EIS) was used to obtain the 18 value by measuring the tunneling resistance through alkanedithiols. The tunneling resistance through alkanedithiols increases exponentially with the molecular length in terms of the mechanism of coherent nonresonant tunneling. beta was 0.51 +/- 0.01 per carbon.

Heterotrimeric G proteins-mediated resistance to necrotrophic pathogens includes mechanisms independent of salicylic acid-, jasmonic acid/ethylene- and abscisic acid-mediated defense signaling

Heterotrimeric G proteins are involved in the defense response against necrotrophic fungi in Arabidopsis. In order to elucidate the resistance mechanisms involving heterotrimeric G proteins, we analyzed the effects of the Gβ (subunit deficiency in the mutant agb1-2 on pathogenesis-related gene expression, as well as the genetic interaction between agb1-2 and a number of mutants of established defense pathways. Gβ-mediated signaling suppresses the induction of salicylic acid (SA)-, jasmonic acid (JA)-, ethylene (ET)- and abscisic acid (ABA)-dependent genes during the initial phase of the infection with Fusarium oxysporum (up to 48 h after inoculation). However, at a later phase it enhances JA/ET-dependent genes such as PDF1.2 and PR4. Quantification of the Fusarium wilt symptoms revealed that Gβ- and SA-deficient mutants were more susceptible than wild-type plants, whereas JA- and ET-insensitive and ABA-deficient mutants demonstrated various levels of resistance. Analysis of the double mutants showed that the Gβ-mediated resistance to F. oxysporum and Alternaria brassicicola was mostly independent of all of the previously mentioned pathways. However, the progressive decay of agb1-2 mutants was compensated by coi1-21 and jin1-9 mutations, suggesting that at this stage of F. oxysporum infection Gβ acts upstream of COI1 and ATMYC2 in JA signaling.

Selection of fungi for accelerated decay in stumps of Eucalyptus spp.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

WOOD NATURAL RESISTANCE OF SEVEN FOREST SPECIES TO WHITE ROT CAUSED BY Pycnoporus sanguineus

This research evaluated the natural resistance of Platanus x acerifolia, Luehea divaricate, Carya illinoinensis, Peltophorum dubium, Araucaria angustifolia, Eucalyptus grandis and Hovenia dulcis, to accelerated decay of the white-rot fungus Pycnoporus sanguineus. The Specific Density at 12% was determinated. The accelerated decay test was conducted with glass bottles (capacity of 500 mL) filled with 100 g of moist soil, autoclaved, and kept at 25 degrees C. The initial establishment of fungal colonies on plates was supported by samples of Pinus elliottii sapwood. In this study, three samples of dimensions 9.0 x 25.0 x 25.0 mm were used for each species evaluated and, after 16 weeks of incubation, the percentage loss of mass was calculated. The degree of natural resistance was performed according to the percentages of mass loss. The results obtained from weight loss were compared by Tukey test at 5%. The natural resistance of woods was not influenced by specific gravity The wood of Carya illinoinensis, Eucalyptus grandis, Platanus x acerifolia, Luehea divaricata and Peltophorum dubium were classified as very resistant, Houvenia dulcis as resistant and Araucaria angustifolia as moderate resistant.

Beech bark disease distribution and resistance in Michigan and fungal endophyte ecology of resistant and susceptible beech (Fagus grandifolia Ehrh.)

Beech bark disease (BBD), a non-native association of the fungal pathogen Neonectria faginata and the beech scale insect Cryptococcus fagisuga, has dramatically affected American beech within North American forests. To monitor the spread and effects of BBD in Michigan, a network of forest health monitoring plots was established in 2001 following the disease discovery in Ludington State Park (Mason County). Forest health canopy condition and basic forestry measurements including basal area were reassessed on beech trees in these plots in 2011 and 2012. The influence of bark-inhabiting fungal endophytes on BBD resistance was investigated by collecting cambium tissue from apparently resistant and susceptible beech. Vigor rating showed significant influences of BBD in sample beech resulting in reduced health and substantiated by significant increases of dead beech basal area over time. C. fagisuga distribution was found to be spatially clustered and widespread in the 22 counties in Michigan's Lower Peninsula which contained monitoring plots. Neonectria has been found in Emmet, Cheboygan and Wexford in the Lower Peninsula which may coincide with additional BBD introduction locations. Surveys for BBD resistance resulted in five apparently resistant beech which were added to a BBD resistance database. The most frequently isolated endophytes from cambium tissue were identified by DNA sequencing primarily as Deuteromycetes and Ascomycetes including Chaetomium globosum, Neohendersonia kickxii and Fusarium flocciferum. N. faginata in antagonism trials showed significant growth reduction when paired with three beech fungal endophytes. The results of the antagonism trial and decay tests indicate that N. faginata may be a relatively poor competitor in vivo with limited ability to degrade cellulose.