Predicting extractives, lignin, and cellulose contents using near infrared spectroscopy on solid wood in Eucalyptus globulus

Near infrared reflectance (NIR) spectroscopy can be used to reliably predict both the physical and chemical wood properties of Eucalyptus. However, studies have been based on ground wood, which is costly and time-consuming to obtain. Predicting wood traits from NIR spectral data taken from solid wood would greatly increase the speed and cost-effectiveness of this procedure. Existing ground wood calibrations were evaluated for the prediction of wood chemistry from NIR spectral data taken from solid wood. Extractives, acid-soluble lignin, and Klason lignin contents were poorly predicted. Total lignin and cellulose contents showed moderate relationships between laboratory values and the NIR predicted values. NIR calibrations were further developed specifically for predicting wood chemistry from solid wood. All calibrations had high R2 values from 0.72 to 0.88, and standard errors of calibration were less than 1.37%. Calibration validation produced high correlation coefficients between predicted and laboratory values for extractives, Klason lignin, total lignin, and cellulose contents with R2 values ranging from 0.67 to 0.87. Acid-soluble lignin content was poorly predicted. This study showed that NIR analysis on solid wood of E. globulus could be reliably used to predict extractives, lignin, and cellulose contents. It also determined that existing ground wood calibrations, although they could give crude estimates of the wood chemistry values, would need to be re-developed for accurate predictions from solid wood

Predicting extractives and lignin contents in Eucalyptus globulus using near infrared reflectance analysis

Lignin and extractive content are important determinants of the pulping quality of wood. Determination of extractive and lignin content using traditional chemical methods is a costly and time-consuming process. Near infrared reflectance (NIR) analysis offers a low cost alternative for prediction of wood quality. Calibrations were developed for the prediction of extractives content, acid-soluble lignin, Klason lignin, and total lignin contents. Each calibration had standard errors of less than 0.6%. Laboratory measurements for a separate set of samples were highly correlated with predicted values (R2 of 0.89 for extractives content, 0.83 for acid-soluble lignin content, 0.97 for Klason lignin content, and 0.99 for total lignin content). It was concluded that NIR analysis is a reliable predictor of extractive and lignin content in Eucalyptus globulus

Depletion of c-Rel from cytokine gene promoters is required for chromatin reassembly and termination of gene responses to T cell activation.

The role of the Nuclear Factor κB (NF-κB) transcription factor family in T cell function has been well described. The c-Rel family member is of particular importance in initiating T cell responses to antigen and regulating activation of inflammatory cytokine genes, including the Interleukin-2 (IL-2) and Granulocyte macrophage colony stimulating factor (GM-CSF) genes. c-Rel is required for chromatin remodeling of these gene promoters, which involves depletion of histones from the promoters in response to T cell activating signals. These chromatin remodeling events precede transcriptional activation of the genes. The subsequent down-regulation of cytokine gene expression is important in the termination of an immune response and here we examine this process at the murine GM-CSF and IL-2 genes. We show that the cytokine mRNA levels rapidly return to basal levels following stimulus removal and this is associated with reassembly of histones onto the promoter. Histone reassembly at the GM-CSF and IL-2 promoters occurs concomitantly with depletion of RelA, c-Rel and RNA polymerase II from the promoters. Furthermore we show that transcriptional down-regulation and chromatin reassembly is dependent on depletion of c-Rel from the nucleus, and that this is regulated by the nuclear translocation of the NF-κB inhibitor, IκBα. The nuclear activation of c-Rel therefore not only regulates the initiation of GM-CSF and IL-2 gene activation in response to T cell activation, but also the termination of these gene responses following the removal of the activating signal

GM-CSF transcriptional down-regulation and promoter chromatin resetting is independent of the cell cycle.

<p>(A–B) Asynchronised and synchronised EL-4 T cells were left unstimulated (NS) or stimulated with PI for 4 h (PI) then the stimulus withdrawn (WD) for the indicated times. GM-CSF mRNA levels relative to GAPDH were then determined by RT-qPCR (A) and promoter accessibility to MNase was determined by CHART-PCR (B). The mean and standard error of three independent experiments is shown. (C) GM-CSF mRNA levels relative to GAPDH were determined in EL-4 T cells stimulated with PI for 4 h (PI) and then the stimulus withdrawn (WD) for 4 h or 20 h, with or without nocodazole (NOC), as indicated. GM-CSF mRNA levels are shown relative to the PI sample which was set at 100%. (D) GM-CSF promoter accessibility to MNase was determined in EL-4 T cells treated as indicated. The mean and standard error of five independent experiments is shown (C–D).</p

GM-CSF transcriptional down-regulation and promoter resetting is associated with nuclear depletion of c-Rel and accumulation of IκBα.

<p>(A–B) GM-CSF mRNA levels, relative to GAPDH (A) and promoter accessibility to MNase (B) was determined in unstimulated EL-4 T cells (NS), cells stimulated with PI for 4 h (PI) and cells in which the stimulus was withdrawn (WD) for the indicated times, or withdrawn for the indicated times in the presence of cycloheximide (CHX), as indicated. mRNA levels are shown in (A) relative to PI treated sample which was set at 100%. The mean and standard error of three independent experiments is shown. (C) Nuclear extracts of EL-4 T cells treated as indicated were subjected to western analysis with the indicated antibodies. (D) c-Rel occupancy at the GM-CSF promoter was determined by ChIP analysis in EL-4 T cells treated as indicated. c-Rel occupancy was normalised to levels in unstimulated cells (NS). The mean and standard error of four independent experiments is shown. (E) Nuclear extracts from EL-4 T cell treated as indicated were subjected to western analysis with the indicated antibodies. (F) IκBα occupancy at the GM-CSF promoter was determined by ChIP analysis of EL-4 T cells stimulated with PI for 4 h and then the stimulus withdrawn for 20 h in the absence or presence of CHX, as indicated. IκBα occupancy was normalized to levels in cells in which stimulus was withdrawn in the absence of CHX. The mean and standard error of three independent experiments is shown.</p

NF-κB and RNA Polymerase II occupy the active GM-CSF promoter.

<p>(A) c-Rel (B) RelA and (C) RNA polymerase II occupancy was determined at the GM-CSF promoter by ChIP analysis of unstimulated EL-4 T cells (NS), cells stimulated for 4 h with PI (PI) and cells in which the stimulus was withdrawn (WD) for the indicated times. Occupancy levels are shown relative to the inactive rhodopsin promoter. The mean and standard error of three independent experiments is shown.</p