Immunity against conserved epitopes dominates after two consecutive exposures to SARS-CoV-2 Omicron BA.1.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure histories become increasingly complex through original and variant-adapted vaccines and infections with viral variants. Upon exposure to the highly altered Omicron spike glycoprotein, pre-immunized individuals predominantly mount recall responses of Wuhan-Hu-1 (wild-type)-imprinted memory B (B) cells mostly targeting conserved non-neutralizing epitopes, leading to diminished Omicron neutralization. We investigated the impact of imprinting in individuals double/triple vaccinated with a wild-type-strain-based mRNA vaccine who, thereafter, had two consecutive exposures to Omicron BA.

Regulation of PaRBOH1-mediated ROS production in Norway spruce by Ca binding and phosphorylation.

Plant respiratory burst oxidase homologs (RBOHs) are plasma membrane-localized NADPH oxidases that generate superoxide anion radicals, which then dismutate to HO, into the apoplast using cytoplasmic NADPH as an electron donor. is the most highly expressed gene in developing xylem as well as in a lignin-forming cell culture of Norway spruce ( L. Karst.

Hunting monolignol transporters: membrane proteomics and biochemical transport assays with membrane vesicles of Norway spruce.

Both the mechanisms of monolignol transport and the transported form of monolignols in developing xylem of trees are unknown. We tested the hypothesis of an active, plasma membrane-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared from developing xylem and lignin-forming tissue-cultured cells of Norway spruce (Picea abies L. Karst.

Dissecting the interaction of photosynthetic electron transfer with mitochondrial signalling and hypoxic response in the Arabidopsis mutant.

The Arabidopsis mutant is tolerant to methyl viologen (MV). MV enhances the Mehler reaction, i.e.

Ray Parenchymal Cells Contribute to Lignification of Tracheids in Developing Xylem of Norway Spruce.

A comparative transcriptomic study and a single-cell metabolome analysis were combined to determine whether parenchymal ray cells contribute to the biosynthesis of monolignols in the lignifying xylem of Norway spruce (). Ray parenchymal cells may function in the lignification of upright tracheids by supplying monolignols. To test this hypothesis, parenchymal ray cells and upright tracheids were dissected with laser-capture microdissection from tangential cryosections of developing xylem of spruce trees.

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch.

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B.

Laser Capture Microdissection Protocol for Xylem Tissues of Woody Plants.

Laser capture microdissection (LCM) enables precise dissection and collection of individual cell types from complex tissues. When applied to plant cells, and especially to woody tissues, LCM requires extensive optimization to overcome such factors as rigid cell walls, large central vacuoles, intercellular spaces, and technical issues with thickness and flatness of the sections. Here we present an optimized protocol for the laser-assisted microdissection of developing xylem from mature trees: a gymnosperm (Norway spruce, ) and an angiosperm (aspen, ) tree.

Dual targeted poplar ferredoxin NADP(+) oxidoreductase interacts with hemoglobin 1.

Previous reports have connected non-symbiotic and truncated hemoglobins (Hbs) to metabolism of nitric oxide (NO), an important signalling molecule involved in wood formation. We have studied the capability of poplar (Populus tremula × tremuloides) Hbs PttHb1 and PttTrHb proteins alone or with a flavin-protein reductase to relieve NO cytotoxicity in living cells. Complementation tests in a Hb-deficient, NO-sensitive yeast (Saccharomyces cerevisiae) Δyhb1 mutant showed that neither PttHb1 nor PttTrHb alone protected cells against NO.

Protein phosphatase 2A (PP2A) regulatory subunit B'γ interacts with cytoplasmic ACONITASE 3 and modulates the abundance of AOX1A and AOX1D in Arabidopsis thaliana.

Organellar reactive oxygen species (ROS) signalling is a key mechanism that promotes the onset of defensive measures in stress-exposed plants. The underlying molecular mechanisms and feedback regulation loops, however, still remain poorly understood. Our previous work has shown that a specific regulatory B'γ subunit of protein phosphatase 2A (PP2A) is required to control organellar ROS signalling and associated metabolic adjustments in Arabidopsis thaliana.

Oxidative metabolism, ROS and NO under oxygen deprivation.

Oxygen deprivation, in line with other stress conditions, is accompanied by reactive oxygen (ROS) and nitrogen species (RNS) formation and is characterised by a set of metabolic changes collectively named as the 'oxidative stress response'. The controversial induction of oxidative metabolism under the lack of oxygen is necessitated by ROS and RNS signaling in the induction of adaptive responses, and inevitably results in oxidative damage. To prevent detrimental effects of oxidative stress, the levels of ROS and NO are tightly controlled on transcriptional, translational and metabolic levels.

Reactive oxygen species and nitric oxide in plant mitochondria: origin and redundant regulatory systems.

Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and fruit carbohydrates may be plenty, whereas oxygen levels are falling. Several enzymatic complexes in mitochondrial electron transport chain (ETC) are capable of reactive oxygen species (ROS) formation under physiological and pathological conditions.

Antioxidants, oxidative damage and oxygen deprivation stress: a review.

Oxidative stress is induced by a wide range of environmental factors including UV stress, pathogen invasion (hypersensitive reaction), herbicide action and oxygen shortage. Oxygen deprivation stress in plant cells is distinguished by three physiologically different states: transient hypoxia, anoxia and reoxygenation. Generation of reactive oxygen species (ROS) is characteristic for hypoxia and especially for reoxygenation.

Ca(2+)-induced high amplitude swelling and cytochrome c release from wheat (Triticum aestivum L.) mitochondria under anoxic stress.

Under stress conditions, mitochondria sense metabolic changes, e.g. in pH, cytoplasmic Ca(2+), energy status, and reactive oxygen species (ROS), and respond by induction of the permeability transition pore (PTP) and by releasing cytochrome c, thus initiating the programmed cell death (PCD) cascade in animal cells.