Stem deformation in young plantations of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) in the boreal forest of Quebec,Canada

Stem deformation has often been observed in young black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) plantations. Whenever important stem deformations are observed at the time of harvesting, timber value is negatively affected especially during the wood transformation process. The present work was undertaken to quantify and qualify the importance of stem deformation of black spruce and jack pine in the boreal forest of central Quebec at the stand and tree levels. In 30 black spruce and jack pine plantations, approximately 22% of spruce trees and 27% of pine trees exhibited stem deformation. The proportion of deformed trees was higher in the youngest plantations and decreased with the age of the plantations. Stem deformation caused the formation of compression wood which is another factor that can reduce the value of wood products. Thirty-nine black spruces and 34 jack pines were analysed at the tree level. On average, compression wood represented 14% and 20% of stem volume in 7- and 10-year old black spruce plantations, respectively. These proportions ranged from 18% in the youngest jack pine plantation to 26% in the oldest one. Stems of both species classified as normal contained a lower volume of compression wood than stems classified as deformed or very deformed. Annual percentages of compression wood and annual shoot length increased significantly with tree age (p < 0.0001 for both variables). Statistically significant correlations were also found between the range of displacement of the stem and the percentage of compression wood. The fewer number of trees with deformed stems in older plantations combined with high compression wood formation suggests that, over time, a deformed tree can become normal and straight in appearance.     

Estimation of the number of exposed people during highly pathogenic avian influenza virus outbreaks in EU/EEA countries,October 2016–September 2018

We estimated that more than 11,000 people were exposed to highly pathogenic avian influenza viruses in EU/EEA countries over the outbreak period October 2016–September 2018 by cross‐linking data submitted by Member States to European Food Safety Authority and EMPRES‐i. A stronger framework for collecting human exposure data is required.     

Evaluation of ionized and total serum magnesium concentrations in hyperthyroid cats

Hyperthyroidism can increase the renal excretion of magnesium and thus cause hypomagnesemia in various species. Anaerobically collected blood samples from 15 hyperthyroid and 40 normal, healthy cats were analyzed with an ion-selective electrode analyzer and a serum biochemical analyzer. There was no significant difference in ionized or total serum magnesium concentration between the 2 groups, but there was a significant difference (P = 0.004) in the ratio of ionized to total serum magnesium concentrations between the healthy cats and the hyperthyroid cats with thyroxine (T4) concentrations at or above the median. There was a significant correlation (r = 0.894, P = 0.000) between the ionized and total magnesium concentrations in the hyperthyroid cats. The hyperthyroid cats had a significantly lower (P = 0.003) total serum protein concentration than the healthy cats. A significant negative correlation (r = -0.670, P = 0.006) was detected between the ionized magnesium and logarithmically transformed total T4 concentrations in the hyperthyroid cats, which suggests that the severity of hyperthyroidism may contribute to a decrease in the ionized magnesium concentration.     

Fate of lignins in soils: A review

Lignins are amongst the most studied macromolecules in natural environments. During the last decades, lignins were considered as important components for the carbon cycle in soils, and particularly for the carbon storage. Thus, they are an important variable in many soil-plant models such as CENTURY and RothC, and appeared determinant for the estimation of the soil organic matter (SOM) pool-size and its stabilization. Recent studies challenged this point of view. The aim of this paper was to synthesise the current knowledge and recent progress about quantity, composition and turnover of lignins in soils and to identify variables determining lignin residence time. In soils, lignins evolve under the influence of various variables and processes such as their degradation or mineralization, as well as their incorporation into SOM. Lignin-derived products obtained after CuO oxidation can be used as environmental biomarkers, and also vary with the degree of degradation of the molecule. The lignin degradation is related to the nature of vegetation and land-use, but also to the climate and soil characteristics. Lignin content of SOM decreases with decreasing size of the granulometric fractions, whereas its level of degradation increases concomitantly. Many studies and our results suggest the accumulation and potential stabilization of a part of lignins in soils, by interaction with the clay minerals, although the mechanisms remain unclear. Lignin turnover in soils could be faster than that of the total SOM. Different kinetic pools of lignins were suggested, which sizes seem to be variable for different soil types. The mechanisms behind different degradation kinetics as well as their potential stabilization behaviour still need to be elucidated.     

Survey of pyrethroid and organophosphate resistance in Brazilian field populations of Rhipicephalus (Boophilus) microplus: Detection of C190A mutation in domain II of the para-type sodium channel gene

The cattle tick Rhipicephalus (Boophilus) microplus causes expressive damage to livestock in Brazil and other countries. Its control is becoming more difficult due to the development of resistance in populations. Early detection of resistance can help in developing effective control strategies. This study evaluated the susceptibility of R. microplus to cypermethrin and chlorpyriphos and was the first attempt to identify the mechanism of resistance (target site insensitivity) in cattle tick populations from Minas Gerais state (Southeastern Brazil). Engorged female ticks were collected from 10 ranches within the state of Minas Gerais, and susceptibility was evaluated with the larval packet test (LPT) using technical grade cypermethrin and chlorpyriphos. It was possible to analyze LPT results of seven populations. Target site insensitivity was investigated in all 10 isolates by using molecular approaches for detection of the T2134A substitution within the domain III S6 segment and the C190A in the domain II S4-5 linker from the para-type sodium channel gene. LPT showed that all seven populations were resistant to cypermethrin with resistance ratio (RR) ranging from 16.0 to 25.0 and 85.7% were resistant to chlorpyriphos (RR=2.2-15.6). Although the T2134A mutation was not detected, the C190A mutation was highly prevalent, being present in 82-100% of the alleles sampled in field populations. A significant correlation was found between the LC50 values for cypermethrin and the frequency of the C190A mutation suggesting that it might be responsible for the phenotypic resistance detected.     

Pigmented-anaerobic bacteria associated with canine periodontitis

The etiology of human periodontal disease has been the focus of considerable research, yet relatively little is known about the causative agents of companion animal periodontitis. In humans, Porphyromonas gingivalis, a black-pigmented anaerobic bacteria (BPAB), has been implicated as the primary periopathogen. It has been demonstrated that BPAB are also found in companion animal periodontal pockets. While some animal BPAB have been individually identified, a study to identify the most frequently isolated subgingival BPAB has not been completed using genetic tools. The objective of this work was to identify the types and relative frequencies of pigmented anaerobic bacteria found in the periodontal pockets of dogs. Porphyromonas salivosa, Porphyromonas denticanis (a novel species) and Porphyromonas gulae were found to be the most frequently isolated BPAB associated with canine periodontitis.     

Lignin turnover kinetics in an agricultural soil is monomer specific

Lignin transformation and decomposition products are generally considered a major source of stable soil organic matter (SOM). Nevertheless this process remains poorly understood in part because lignin is a heterogeneous biopolymer composed of several types of phenol monomers, which potentially display specific and contrasting decomposition kinetics in soils. Here, we compared the specific in situ turnover kinetics of individual lignin monomers in a Paris-basin loamy soil through natural ¹³C labeling of SOM generated in a series of 1-9-year chronosequences of maize monoculture (C4, δ¹³C −12‰) replacing wheat (C3, −27‰). Lignin monomers were released by CuO oxidation, quantified by gas chromatography (GC)/flame ionization detection (FID) and their ¹³C content was determined by GC coupled via a combustion interface to isotope ratio mass spectrometry (GC/C-IRMS). We calculated the proportion of C4-derived OC in lignin monomer pools by applying the isotopic mass balance equation to each lignin monomer.Individual C4-derived phenols displayed contrasting accumulation rates in soils over time, confirming the monomer-specific nature of their transformation kinetics. In proportion to total lignin phenols in soils, syringyl (S) and cinnamyl (C) phenols from maize accumulated faster than their vanillyl (V) counterparts. Consequently, the turnover kinetics of lignin-derived V-moieties may be slower than those of S and C ones. Incorporation of maize-derived carbon was faster in the aldehyde than in the acid pool for V-type units, while the opposite was observed for S-units. These in situ trends for phenol monomers and V-, S- and C-moieties were remarkably similar to the trends described in the literature with laboratory incubation or litterbag studies.None of the observed kinetics had a linear shape. Using only the extreme points of the chronosequence to calculate the kinetic parameters would result, for all the lignin monomers, in underestimating the turnover kinetics at the beginning of the kinetics and overestimating it for longer times. This observation underlines the importance of comprehensive ¹³C time-sequence labelling experiments such as provided at the Closeaux site, to accurately compute the kinetic parameters of SOM for the 1st years after the vegetation change.     

The effect of photoperiod on flowering and TPS production in the warm tropics

Summary Three similar field experiments with five cultivars were carried out to evaluate the effect of a 5-hour extension of the natural daylength and a 3-hour night break on flowering and TPS production in the warm tropics. Shoot length, number of inflorescence positions per plant and number of flowers per inflorescence varied considerably between the experiments. In each experiment, the supplementary photoperiods delayed cessation of shoot growth and thereby increased the orders of branching and the number of inflorescence positions per plant. The photoperiod treatments significantly increased the number of flowers at the last produced inflorescence positions, but not at other ones. Pollen production and quality, berry set, seed set and 100-seed weight were not affected by the photoperiod treatments. TPS production was characterized by variability in flowering and low and variable seed production per flower.     

Mercerization mediated modification of cellulosic fibers with NIPAAm and some compounds with antioxidant activity

A two step process was used for the modification of a cellulose/chitin mixed fibers: the first step was an alkali treatment with a NaOH solution (20 %), which was followed by the reaction with one of the reagents such as Nisopropylacrylamide, p-hydroxybenzoic acid, gallic acid, or eugenol. Both the samples activated with the alkali treatment and modified with chemicals were characterized by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and thermal analysis. Results revealed the morphological and structural changes of the fiber surface after the surface grafting, which significantly altered the cellulose/chitin mixed fiber properties. Thermal analysis results showed an increase in the thermal stability of the treated samples. Antioxidant activity of cellulose/chitin mixed fibers modified with phenolic compounds showed that the efficiency depends on the chemical nature of phenolic compound.