Search Results (6)

Introduction: The contribution of SARS-CoV-2 infection to the severity of placental alterations in preeclampsia remains unclear. This study aimed to evaluate the morphological changes in placentas of women who experienced COVID-19 during pregnancy, with a focus on the presence or absence of preeclampsia. Materials and Methods: The study included placentas from: (1) patients with both COVID-19 during pregnancy and preeclampsia (n = 20, 2022); (2) patients with COVID-19 during pregnancy without preeclampsia (n = 20, 2022); (3) patients with preeclampsia but without COVID-19 (n = 5, 2019); (4) patients with physiological pregnancies without COVID-19 or gestational complications (n = 5, 2019). Histological and immunohistochemical examinations of the placentas were performed using antibodies against the SARS-CoV-2 spike protein, DPP4 (CD26), and VEGF. Results: Placentas from patients with both COVID-19 and preeclampsia demonstrated the most pronounced stromal and vascular alterations, including pseudo-infarctions and villous fibrosis. Chorangiosis, excessive fibrinoid deposition in the intervillous space, and accelerated villous maturation with an increased number of syncytial knots were more common in the preeclampsia groups, regardless of prior COVID-19 infection. Symptomatic forms of coronavirus infection were associated with more severe manifestations of malperfusion. Expression of the SARS-CoV-2 spike protein was detected in 78% of syncytiotrophoblast cells and 37% of decidual cells in 28 of 40 placentas from women with previous COVID-19, while its presence in the vascular endothelium, macrophages, and villous fibroblasts was focal, as was CD26 expression. VEGF expression did not differ significantly between patients with and without COVID-19. Conclusions: COVID-19 is associated with more pronounced stromal–vascular alterations in the placenta; however, not all of these changes are directly caused by the virus itself but rather reflect the severe course of preeclampsia. Inflammatory alterations are nonspecific for COVID-19, even though CD26 and the SARS-CoV-2 spike protein are detectable in nearly all placental structures, whereas VEGF levels remain comparable to those observed in placentas prior to the coronavirus pandemic. Full article

Olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi, severely impacts olive tree yield and oil quality. Early and accurate detection of the bacterium’s presence, particularly in asymptomatic plants, is crucial for effective disease management. This study aimed to develop an improved protocol for processing plant samples and adapting quantitative PCR to droplet digital PCR (ddPCR). For this purpose, four plant preparations—EW (external washing), PELLET (bacterial concentration), and enrichment in liquid media for 24 or 48 h (24hE, 48hE)—were tested using spiked samples. The ddPCR was set up and compared with qPCR to evaluate analytical sensitivity and specificity. Additionally, field samples from symptomatic and asymptomatic olive orchards were tested to evaluate the performance of the selected methods in naturally infected plants. ddPCR showed higher sensitivity than qPCR, particularly with the PELLET and 24hE preparations. The PELLET from the spiked sample preparation achieved a limit of detection of 10 CFU/mL for both molecular tests. The ddPCR, combined with the PELLET preparation, offers a highly sensitive and reliable tool for detecting P. savastanoi pv. savastanoi in asymptomatic olive material. This protocol shows great potential for improving early bacterial detection and disease prevention, thus aiding control strategies in nurseries and olive orchards, and supporting the production of certified plant propagation material. Full article

We studied the associations between the stem quality, phenology, and genetic structure by genotyping the phenotypic variation at 15 genomic SSR makers of 208 mature European beech trees in four artificially established stands in Lithuania. The genetic differentiation among the stands was significant (D_EST = 0.029**). The stand NOR1 of Carpathian origin significantly differed from the remaining three stands of Bavarian origin at the highest 0.001 significance level. In most of the stands, the early flushing trees were of significantly worse stem quality. Within each of the stands, the Bayesian clustering identified 2 to 3 genetic groups, among which the differentiation was markedly stronger than between the stands (D_EST 0.095*** to 0.142***). The genetic groups differed markedly in stem quality and phenology as well as inbreeding levels. We conclude that (a) the genetic structuring in European beech stands strongly depends on non-random mating owing to phenology variation among the relative groups, (b) due to strong relationship among phenology, adaptedness and stem morphotype, this genetic variation is reflected by the stem morphotype. Full article

Increasing resistance against biotic and abiotic factors is an important goal of forest tree breeding. The aim of the present study was to develop a root rot resistance index for Scots pine breeding and evaluate its effectiveness. The productivity, branch diameter, branchiness, stem straightness, spike knots, and damage from natural infection of root rot in 154 Scots pine open-pollinated families from Latvia were evaluated through a progeny field trial at the age of 38 years. Trees with decline symptoms were sampled for fungal isolations. Based on this information and kriging estimates of root rot, 35 affected areas (average size: 108 m²; total 28% from the 1.5 ha trial) were delineated. Resistance index of a single tree was formed based on family adjusted proportion of live to infected trees and distance to the center of affected area. Heritability for resistance to root rot based on the value of this index, was high (0.37) and comparable to indices of growth traits. Correlations of family breeding estimates between resistance to root rot and the other traits were not significant, except for a weak, yet significant, positive correlation with diameter at breast height and branch diameter. Selection index including only growth traits (height and stem volume) had a negligible effect on damage by root rot. We detected a maximum genetic gain in resistance index of 33.7% when incorporating it into the selection index with positive gains for growth traits (6.5–11.0%). Two-stage selection with prior selection of the most resistant families was not superior to the use of selection index with only rot resistance included. Overall; rot resistance index appeared to be an effective tool in tree breeding for the selection of more resistant families, using the existing trials with natural (uncontrolled) infection Full article

Silver birch (Betula pendula Roth) is productive on abandoned agriculture land, and thus might be considered as an option for profitable plantation forestry. Application of the most productive genotypes is essential. However, information about genetic gains in low-density plantations is still lacking. A 40-year-old low-density (400 trees ha⁻¹) plantation of 22 grafted silver birch plus-tree clones growing on former agricultural land in the central Latvia was studied. Although grafted plantations are not common in commercial forestry, the trial provided an opportunity to assess genetic parameters of middle-aged birch. The plantation that had reached the target diameter for final harvest (DBH (diameter at breast height) = 27.7 ± 5.5 cm) had an 85% survival rate, and stemwood productivity was 5.25 m³ ha⁻¹year⁻¹. Still, rootstock × scion interaction and cyclophysis might have caused some biases. Broad-sense heritability (H²) ranged from 0.02 for probability of spike knots to 0.40 for branch angle. Estimated H² for monetary value of stemwood was 0.16. In general, the correlations between growth and stem quality traits were weak, implying independent genetic control, though branchiness strongly correlated with diameter at breast height. The monetary value of stemwood strongly correlated with productivity traits. The observed correlations suggested that productivity and stem quality of birch might be improved simultaneously by genetic selection. Full article

This article describes aspects within an experimental program aimed at improving the structural performance of cracked solid fir-wood beams repaired with Basalt Fiber Reinforced Polymer (BFRP) spikes. Fir wood is characterized by its low density, low compression strength, and high level of defects, and it is likely to distort when dried and tends to fail under tension due to the presence of cracks, knots, or grain deviation. The proposed repair technique consists of the insertion of BFRP spikes into timber beams to restore the continuity of cracked sections. The experimental efforts deal with the evaluation of the bending strength and deformation properties of 24 timber beams. An artificially simulated cracking was produced by cutting the wood beams in half or notching. The obtained results for the repaired beams were compared with those of solid undamaged and damaged beams, and increases of beam capacity, bending strength and of modulus of elasticity, and analysis of failure modes was discussed. For notched beams, the application of the BFRP spikes was able to restore the original bending capacity of undamaged beams, while only a small part of the original capacity was recovered for beams that were cut in half. Full article