Dirigent (DIR) proteins were found to mediate regio- and stereoselectivity of bimolecular phenoxy radical coupling during lignan biosynthesis. Here we summarize the current knowledge of the importance of DIR proteins in lignan and lignin biosynthesis and highlight their possible importance in plant development. We focus on the still rather enigmatic Arabidopsis DIR gene family, discussing the few members with known functional importance. We comment on recent discoveries describing the detailed structure of two DIR proteins with implications in the mechanism of DIR-mediated catalysis. Further, we summarize the ample evidence for stress-induced dirigent gene expression, suggesting the role of DIRs in adaptive responses. In the second part of our work, we present a preliminary bioinformatics-based characterization of the AtDIR family. The phylogenetic analysis of AtDIRs complemented by comparison with DIR proteins of mostly known function from other species allowed us to suggest possible roles for several members of this family and identify interesting AtDIR targets for further study. Finally, based on the available metadata and our in silico analysis of AtDIR promoters, we hypothesize about the existence of specific transcriptional controls for individual AtDIR genes and implicate them in various stress responses, hormonal regulations, and developmental processes.

Integrating important environmental signals with intrinsic developmental programmes is a crucial adaptive requirement for plant growth, survival, and reproduction. Key environmental cues include changes in several light variables, while important intrinsic (and highly interactive) regulators of many developmental processes include the phytohormones cytokinins (CKs) and ethylene. Here, we discuss the latest discoveries regarding the molecular mechanisms mediating CK/ethylene crosstalk at diverse levels of biosynthetic and metabolic pathways and their complex interactions with light. Furthermore, we summarize evidence indicating that multiple hormonal and light signals are integrated in the multistep phosphorelay (MSP) pathway, a backbone signalling pathway in plants. Inter alia, there are strong overlaps in subcellular localizations and functional similarities in components of these pathways, including receptors and various downstream agents. We highlight recent research demonstrating the importance of CK/ethylene/light crosstalk in selected aspects of plant development, particularly seed germination and early seedling development. The findings clearly demonstrate the crucial integration of plant responses to phytohormones and adaptive responses to environmental cues. Finally, we tentatively identify key future challenges to refine our understanding of the molecular mechanisms mediating crosstalk between light and hormonal signals, and their integration during plant life cycles.

The processes of plant nutrition, stress tolerance, plant growth, and development are strongly dependent on transport of mineral nutrients across cellular membranes. Plant membrane transporters are key components of these processes. Among various membrane transport proteins, the monovalent cation proton antiporter (CPA) superfamily mediates a broad range of physiological and developmental processes such as ion and pH homeostasis, development of reproductive organs, chloroplast operation, and plant adaptation to drought and salt stresses. CPA family includes plasma membrane-bound Na + /H + exchanger (NhaP) and intracellular Na + /H + exchanger NHE (NHX), K + efflux antiporter (KEA), and cation/H + exchanger (CHX) family proteins. In this review, we have completed the phylogenetic inventory of CPA transporters and undertaken a comprehensive evolutionary analysis of their development. Compared with previous studies, we have significantly extended the range of plant species, including green and red algae and Acrogymnospermae into phylogenetic analysis. Our data suggest that the multiplication and complexation of CPA isoforms during evolution is related to land colonisation by higher plants and associated with an increase of different tissue types and development of reproductive organs. The new data extended the number of clades for all groups of CPAs, including those for NhaP/SOS, NHE/NHX, KEA, and CHX. We also critically evaluate the latest findings on the biological role, physiological functions and regulation of CPA transporters in relation to their structure and phylogenetic position. In addition, the role of CPA members in plant tolerance to various abiotic stresses is summarized, and the future priority directions for CPA studies in plants are discussed.

Polycystic ovarian syndrome (PCOS) is the most common endocrine–metabolic disorder affecting a vast population worldwide; it is linked with anovulation, mitochondrial dysfunctions and hormonal disbalance. Mutations in mtDNA have been identified in PCOS patients and likely play an important role in PCOS aetiology and pathogenesis; however, their causative role in PCOS development requires further investigation. As a low-grade chronic inflammation disease, PCOS patients have permanently elevated levels of inflammatory markers (TNF-α, CRP, IL-6, IL-8, IL-18). In this review, we summarise recent data regarding the role of mtDNA mutations and mitochondrial malfunctions in PCOS pathogenesis. Furthermore, we discuss recent papers dedicated to the identification of novel biomarkers for early PCOS diagnosis. Finally, traditional and new mitochondria-targeted treatments are discussed. This review intends to emphasise the key role of oxidative stress and chronic inflammation in PCOS pathogenesis; however, the exact molecular mechanism is mostly unknown and requires further investigation.

To investigate the evolutionary history of the current pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a total of 137 genomes of coronavirus strains with release dates between January 2019 and 25 March 2020, were analyzed. To investigate the potential intermediate host of the SARS-CoV-2, we analyzed spike glycoprotein sequences from different animals, with particular emphasis on bats. We performed phylogenetic analysis and structural reconstruction of the spike glycoproteins with subsequent alignment and comparison. Our phylogenetic results revealed that SARS-CoV-2 was more similar to the bats' betacoronavirus isolates: HKU5-related from Pipistrellus abramus and HKU4-related from Tylonycteris pachypus. We also identified a yak betacoronavirus strain, YAK/ HY24/CH/2017, as the closest match in the comparison of the structural models of spike glycoproteins. Interestingly, a set of unique features has been described for this particular strain of the yak betacoronavirus. Therefore, our results suggest that the human SARS-CoV-2, responsible for the current outbreak of COVID-19, could also come from yak as an intermediate host.betacoronavirus, COVID-19, SARS-CoV-2, spike glycoprotein DABRAVOLSKI AND KAVALIONAK | 3 N-terminal domain (pfam16451), C-terminal S1 corresponds to the spike receptor-binding domain (pfam09408), and S2 domain contains coronavirus S1 glycoprotein (pfam01600), and coronavirus S2 glycoprotein (pfam01601) as subdomains ( Figure S1).Canonical spike glycoprotein contains four domains, each of which plays a specific function. It is known that both spike glycoprotein N-terminal domain (pfam16451) and spike receptorbinding domain (pfam09408) participate in specific receptor binding. The N-terminal domain binds to carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in mouse hepatitis coronavirus, and binds sugar in porcine transmissible gastroenteritis virus. 13 Spike receptor-binding domain binds to the aminopeptidase N or angiotensin-converting enzyme 2 (ACE2) in coronaviruses. 14 An interplay between coronavirus S1 glycoprotein (pfam01600) and coronavirus S2 glycoprotein (pfam01601) is required for the attachment of spike to susceptible tissues and subsequent fusion. 15The phylogenetic data reported above show that the new human-delivered SARS-CoV-2 spike glycoproteins cluster with two betacoronaviruses, HKU4-and HKU5-related, delivered from the hosts T pachypus and P abramus, respectively. Also, as seen from the phylogenetic tree ( Figure S1), these two sequences deviate from the other bat coronavirus sequences, suggesting that these bat coronaviruses are homologous and genetically more similar to human-delivered SARS-CoV-2 than to the other bats' coronaviruses.In general, these data support phylogenetic results obtained by previous researches based on (a) whole-genome; (b) nonstructural proteins NS7b and NS8; (c) spike glycoprotein, and (d) nucleocapsid protein. 16For the next experiment, based on the alignment and comparison of the structures, MERS ...

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We examined the levels and distribution of post-translationally modified histones and protamines in human sperm. Using western blot immunoassay, immunofluorescence, mass spectrometry (MS), and FLIM-FRET approaches, we analyzed the status of histone modifications and the protamine P2. Among individual samples, we observed variability in the levels of H3K9me1, H3K9me2, H3K27me3, H3K36me3, and H3K79me1, but the level of acetylated (ac) histones H4 was relatively stable in the sperm head fractions, as demonstrated by western blot analysis. Sperm heads with lower levels of P2 exhibited lower levels of H3K9ac, H3K9me1, H3K27me3, H3K36me3, and H3K79me1. A very strong correlation was observed between the levels of P2 and H3K9me2. FLIM-FRET analysis additionally revealed that acetylated histones H4 are not only parts of sperm chromatin but also appear in a non-integrated form. Intriguingly, H4ac and H3K27me3 were detected in sperm tail fractions via western blot analysis. An appearance of specific histone H3 and H4 acetylation and H3 methylation in sperm tail fractions was also confirmed by both LC-MS/MS and MALDI-TOF MS analysis. Taken together, these data indicate that particular post-translational modifications of histones are uniquely distributed in human sperm, and this distribution varies among individuals and among the sperm of a single individual.

Kruppel like factor 2 (KLF2) is a mechanosensitive transcription factor participating in the regulation of vascular endothelial cells metabolism. Activating KLF2 in endothelial cells induces eNOS (endothelial nitric oxide synthase) expression, subsequent NO (nitric oxide) release, and vasodilatory effect. In addition, many KLF2-regulated genes participate in the anti-thrombotic, antioxidant, and anti-inflammatory activities, thereby preventing atherosclerosis development and progression. In this review, we summarise recent evidence suggesting that KLF2 plays a major role in regulating atheroprotective effects in endothelial cells. We also discuss several recently identified repurposed drugs and natural plant-based bioactive compounds with KLF2-mediated atheroprotective activities. Herein, we present a comprehensive overview of the role of KLF2 in atherosclerosis and as a pharmacological target for different drugs and natural compounds and highlight the potential application of these phytochemicals for the treatment of atherosclerosis.