Polar Growth Research Articles

TLR2-Bound Cancer-Secreted Hsp70 Induces MerTK-Mediated Immunosuppression and Tumorigenesis in Solid Tumors

Background: A hallmark of cancer is the presence of an immunosuppressive tumor microenvironment (TME). Immunosuppressive M2 macrophages (MΦs) in the TME facilitate escape from immune surveillance and promote tumor growth; therefore, TME-induced immunosuppression is a potent immunotherapeutic approach to treating cancer. Methods: Cancer cell-secreted proteins were detected by using liquid chromatography–mass spectrometry (LC-MS). Neutralizing antibodies (nAbs) were used to assess which proteins were involved in MΦs polarization and differentiation. The protein–protein interaction was characterized using co-immunoprecipitation and immunofluorescence assays. Cancer-secreted heat shock protein 70 (Hsp70) protein was quantified using an enzyme-linked immunosorbent assay (ELISA). MΦ polarization and tumor growth were assessed in vivo with subcutaneous LLC-GFP tumor models and toll-like receptor 2 (TLR2) knockout mice; in vitro assessments were conducted using TLR2 knockout and both LLC-GFP and LN227 lentiviral-mediated knockdown (KD) cells. Results: Cancer cells released a secreted form of Hsp70 that acted on MΦ TLR2 to upregulate Mer receptor tyrosine kinase (MerTK) and induce MΦ M2 polarization. Hsp70 nAbs led to a reduction in CD14 expression by 75% in THP-1 cells in response to Gli36 EMD-CM. In addition, neutralizing TLR2 nAbs resulted in a 30% and 50% reduction in CD14 expression on THP-1 cells in response to MiaPaCa-2 and Gli36 exosome/microparticle-depleted conditioned media (EMD-CMs), respectively. Hsp70, TLR2, and MerTK formed a protein complex. Tumor growth and intra-tumor M2 MΦs were significantly reduced upon cancer cell Hsp70 knockdown and in TLR2 knockout mice. Conclusions: Cancer-secreted Hsp70 interacts with TLR2, upregulates MerTK on MΦs, and induces immunosuppressive MΦ M2 polarization. This previously unreported action of secreted Hsp70 suggests that disrupting the Hsp70-TLR2-MerTK interaction could serve as a promising immunotherapeutic approach to mitigate TME immunosuppression in solid cancers.

FhaA plays a key role in mycobacterial polar elongation and asymmetric growth.

Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, remains a global health concern. Unlike most well-studied model bacilli, mycobacteria possess a distinctive and complex cell envelope, as well as an asymmetric polar growth mode. However, the proteins and mechanisms that drive cell asymmetric elongation in these bacteria are still not well understood. This study sheds light on the role of the protein FhaA in this process. Our findings demonstrate that FhaA localizes at the septum and asymmetrically to the poles, with a preference for the fast-growing pole. Furthermore, we showed that FhaA is essential for population heterogeneity and asymmetric polar elongation and plays a role in the precise subcellular localization of the cell wall biosynthesis machinery. Mycobacterial asymmetric elongation results in a physiologically heterogeneous bacterial population which is important for pathogenicity and response to antibiotics, stressing the relevance of identifying new factors involved in these still poorly characterized processes.

The Role of Reactive Oxygen Species in the In Vivo Germination and Growth of Petunia (Petunia hybrida E. Vilm.) Male Gametophyte in the Progamic Phase of Fertilization

The potential role of reactive oxygen species (ROS) is studied in the male gametophytes of petunia (Petunia hybrida E. Vilm.) grown in vivo with a focus on its germination, growth support in the progamic stage of fertilization, and the function of the mechanism underlying S-RNase-based self-incompatibility. Exogenous treatment with H2O2 influences the in vivo germination and polar growth of pollen tubes (PTs), which manifests as the acceleration or inhibition of these processes depending on its concentration, time interval after pollination, and pollination variant. The H2O2 treatment of the stigma somewhat stimulates the PT elongation in the late stages of self-incompatible pollination (4–8 h) versus the strong PT inhibition observed during the first hour of germination. A different pattern is observable in cross-compatible pollination: the H2O2 treatment of pistils inhibits PT growth during the overall pollination at all tested concentrations. Treatment of pistils with the NADPH oxidase inhibitor diphenylene iodonium chloride (DPI) strongly inhibited the growth of PTs in both pollination variants. In addition, DCF-DA staining confirms that ROS are formed in pollen, PTs, stigma of nonpollinated pistil, and the pistil itself in all pollination variants. The PT growth during the function of the self-incompatibility mechanism is arrested at high ROS concentrations, which is presumably associated with the SI-induced programmed cell death. Our results demonstrate that ROS are a necessary component of pollen, PTs, exudate, and stigma cells and contribute to successful reproduction. This study provides a deeper insight into the ROS functions during the PT growth in an in vivo system.

Polar localization and local translation of RHO-RELATED PROTEIN FROM PLANTS2 mRNAs promote root hair growth in Arabidopsis.

Root hairs are tip-growing cells that anchor plants in the soil and are critical for water uptake, nutrient acquisition, and plant-environment interactions. While the molecular mechanisms that maintain the polar growth of root hairs through the asymmetric distribution of proteins, such as RHO-RELATED PROTEIN FROM PLANTS 2 (ROP2), have been described, it is unclear whether and how the transcripts encoding these tip-localized proteins are polarly localized and locally translated. Here, we demonstrated that ROP2 mRNA exhibits polar localization in Arabidopsis (Arabidopsis thaliana) root hairs. We showed that region VI (250-350 bp downstream of the stop codon) of the ROP2 3' untranslated region (UTR) is necessary for proper mRNA localization. Moreover, region VI-mediated ROP2 mRNA polar localization was required for local translation of ROP2 transcripts, contributing to the proper subcellular localization of ROP2. Region III (100-200 bp downstream of the stop codon) influenced the local translation of ROP2 mRNA. Phenotypic investigations demonstrated that both regions III and VI of the ROP2 3' UTR play crucial roles in modulating root hair growth. These findings help explain the local protein biosynthesis of ROP2, advancing our understanding of the regulatory mechanism and genetic basis of mRNA localization and local translation in plants.

Mycobacterium tuberculosis CrgA Forms a Dimeric Structure with Its Transmembrane Domain Sandwiched between Cytoplasmic and Periplasmic β-Sheets, Enabling Multiple Interactions with Other Divisome Proteins.

CrgA is a key transmembrane (TM) protein in the cell division process of Mycobacterium tuberculosis (Mtb), the pathogen responsible for tuberculosis. While many of the Mtb divisome proteins have been identified, their structures and interactions remain largely unknown. Previous studies of CrgA using oriented-sample solid-state NMR have defined the tilt and rotation of the TM helices, but the cytoplasmic and periplasmic domains and even the oligomeric state were uncharacterized. Here, combining oriented-sample and magic-angle spinning solid-state NMR spectra, we solved the full-length structure of CrgA. The structure features a dimer with a TM domain sandwiched between a cytoplasmic β-sheet and a periplasmic β-sheet. The β-sheets stabilize dimerization, which in turn increases CrgA's ability to participate in multiple protein interactions. Within the membrane, CrgA binds FtsQ, CwsA, PbpA, FtsI, and MmPL3 via its TM helices; in the cytoplasm, Lys23 and Lys25 project outward from the β-sheet to interact with acidic residues of FtsQ and FtsZ. The structural determination of CrgA thus provides significant insights into its roles in recruiting other divisome proteins and stabilizing their complexes for Mtb cell wall synthesis and polar growth.

Study on Structure and Electrochemical Properties of Zn-Sulfolane Based Electrolyte Solution

The zinc secondary batteries (ZIBs) are promoting as one of the next-generation batteries using zinc with a high theoretical capacity as a negative electrode. However, the dendrite growth due to repeated charging and discharging are disadvantages. Deep eutectic solvents (DESs), which are obtained by mixing two or more compounds consisting of a hydrogen bond acceptor and a hydrogen bond donor, have suppressed dendrite growth.[1] Mixing Zn (ClO4)2・6H2O (solid) and sulfolane (SL, melting point 27.5 ℃) yields a DES and the DES prevents dendrite growth. However, the whisker-like Zn deposition is observed at high current density, suggesting that the DES cannot inherently prevent dendrite growth.[2] On the other hand, Dokko et al. have reported that the Li+ hopping conduction occurs in SL based super-concentrated electrolyte solution, suppressing concentration polarization.[3] Liquid structure plays a crucial role in the Li+ hopping conduction. In this work, to develop a DES that prevents dendrite growth by suppressing the concentration polarization, we prepared the SL based DESs consisting of various anions.Zn(ClO4) DES was prepared by mixing Zn (ClO4)2・6H2O and SL. We also prepared the DES with the anion changed to Zn (TfO)2. The liquid structures of Zn-SL DES were observed using a laser Raman spectrophotometer NRS-4500. The chronoamperometry of the Zn-symmetric cell was measured at room temperature. An electrochemical measurement system (SP-150, Bio-logic) was used for the electrochemical measurement.In the Raman spectrum of neat SL, a Raman band assigned to the scissoring vibration of SO2 is observed at 567 cm-1. This Raman bands appears at 571 cm-1 and 574 cm-1 in the Raman spectrum for Zn (ClO4)2 DES and Zn (TfO)2 DES, respectively. In addition, the FWHM of the band of Zn (TfO)2 DES is larger than that of Zn (ClO4)2 DES. In high concentration Li-SL electrolyte, Li+ interacts not only with SL but also with anions to form the contact ion pairs (CIP) and aggregates (AGG) in which the anion cross-links Li+. As these liquid structure form, the Raman band shifts to the high wavenumber and broadens. Therefore, the CIP and AGG may be easily formed in Zn (TfO)2 DES. This is expected to suppress concentration polarization and dendrite growth. In the case of migration-controlled Zn2+ transport, the current should increase with increasing the applied voltage. For the Zn (ClO4)2 DES, there was no increase in current density of the symmetric cell with increasing applied voltage. In contrast, for the Zn (TfO)2 DES, the current value increased continuously with increasing applied voltage, reaching a high value of 10.8 mA cm-2 at 600 mV. In addition, despite the low conductivity of Zn (TfO)2 DES, the high current density was observed upon polarization. We believe that this is due to the rapid transport of zinc by forming CIP and AGG. However, for Zn (TfO)2 DES, the current decay due to concentration polarization is observed at large polarization. To suppress the concentration polarization, Zn2+ concentration was increased and then the chronoamperometry measurements was conducted again. In the Zn (TfO)2 DES, there was no increase in the current density of the symmetric cell with increasing the applied voltage. On the other hand, the current density of the symmetric cell with Zn (ClO4)2 DES suddenly increased from 300 mV. This may be due to a change in electrode area caused by the formation of dendrites.４．References[1] Funian Mo, Guojin Liang, Qiangqiang Meng, et. al. Energy Environ. Sci., 706-715 (2019)[2] Xidong Lin, Guodong Zhou, Matthew J. Robson, et. al. Adv.Funct.Mater. 2109322 (2021)[3] Kaoru Dokko, Daiki Watanabe, et. al. J.Phys.Chem. B, 122, 10736–10745, (2018)

Subcellular Proteomic Mapping of Lysine Lactylation.

Protein lactylation is a novel post-translational modification (PTM) involved in many important physiological processes such as macrophage polarization, immune regulation, and tumor cell growth. However, traditional methodologies for studying lactylation have predominantly relied on peptide enrichment from whole-cell lysates, which tend to favor the detection of high-abundance peptides, thus limiting the identification of low-abundance lactylated peptides. To address this limitation, here, we employed subcellular fractionation to separate proteins and map lactylated peptides from each isolated subcellular fraction using a model cell line. In brief, we identified 1,217 lysine lactylation (Kla) sites on 553 proteins across four subcellular fractions. Subsequent pathway enrichment analysis revealed that Kla proteins participate in distinct pathways depending on the subcellular contexts. In addition, this subcellular fractionation method enabled the discovery of 36 previously unreported Kla proteins and 223 novel Kla sites, many of which are present in low abundance. Notably, several proteins contain multiple newly identified Kla sites, exemplified by the transcriptional regulator ATRX. Furthermore, our results indicate the possibility of PTM crosstalk between Kla and other PTMs such as ubiquitination and sumoylation. In conclusion, subcellular fractionation facilitates the identification of Kla proteins that have been previously uncovered and could be overlooked by affinity enrichment of whole-cell lysates.

A dispensable SepIVA orthologue in Streptomyces venezuelae is associated with polar growth and not cell division

BackgroundSepIVA has been reported to be an essential septation factor in Mycolicibacterium smegmatis and Mycobacterium tuberculosis. It is a coiled-coil protein with similarity to DivIVA, a protein necessary for polar growth in members of the phylum Actinomycetota. Orthologues of SepIVA are broadly distributed among actinomycetes, including in Streptomyces spp.ResultsTo clarify the role of SepIVA and its potential involvement in cell division in streptomycetes, we generated sepIVA deletion mutants in Streptomyces venezuelae and found that sepIVA is dispensable for growth, cell division and sporulation. Further, mNeonGreen-SepIVA fusion protein did not localize at division septa, and we found no evidence of involvement of SepIVA in cell division. Instead, mNeonGreen-SepIVA was accumulated at the tips of growing vegetative hyphae in ways reminiscent of the apical localization of polarisome components like DivIVA. Bacterial two-hybrid system analyses revealed an interaction between SepIVA and DivIVA. The results indicate that SepIVA is associated with polar growth. However, no phenotypic effects of sepIVA deletion could be detected, and no evidence was observed of redundancy with the other DivIVA-like coiled-coil proteins Scy and FilP that are also associated with apical growth in streptomycetes.ConclusionsWe conclude that S. venezuelae SepIVA, in contrast to the situation in mycobacteria, is dispensable for growth and viability. The results suggest that it is associated with polar growth rather than septum formation.

How Social Identities Facilitate the Growth of Affective Political Polarization

This study explored the relationships between a selection of social identity factors and affective political polarization among adults in the United States. A broad selection of literature was reviewed and employed in informing a descriptive and inferential statistical analysis of 2008 and 2020 American National Election Studies (ANES) survey data. Multiple regression was used to describe and quantify the relationships between selected variables and affective polarization within the datasets. These methods were paired with tests for differences in means in a comparative analysis of the 2008 and 2020 demographic and political environments, which revealed a statistically significant difference in the levels of affective polarization between the two years. Ideological polarization and ageing stood out as the factors that contributed most heavily to this this growth in affective polarization. Broadly, these findings suggested that demographic and psychographic shifts may have played a role in facilitating growth of affective political polarization across the years. Finally, a post-hoc analysis identified the growth of affective polarization as originating from increased hostility for political out-groups, highlighting the need for further research into other political, social, and economic events that may have triggered the growth of affective polarization.

Protein Involved in Tip Elongation (PITE) regulates root hair growth in rice.

Polar tip growth in plants occurs only in root hairs and pollen tubes. In particular, root hair growth is considered very important in the growth of plants, as it is critical for water and nutrient absorption. Polar tip growth is regulated by various factors, including plant hormones such as abscisic acid (ABA) and gibberellin (GA) and cell wall modifications. We aimed to elucidate the effects and mechanisms on tip growth of a novel gene containing the domain of unknown function (DUF) 3511. We found that Protein Involved in Tip Elongation (PITE) is involved in root hair development in rice (Oryza sativa L.). PITE protein was observed in the plasma membrane and cytoplasm of root hairs. Pite mutants generated by the CRISPR/Cas9 system showed a shorter root hair phenotype compared to the wild type. Through RNA sequencing and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis, we found that the expression of genes that affect cell wall rigidity and GA metabolism-related genes were differently regulated in pite mutants. PITE could interact with acyl transferase and haloacid dehalogenase-like hydrolase (HAD9) in the nucleus and cytoplasm. Our study suggests that PITEs containing the DUF3511 domain regulate root hair growth in rice by mediating the expression of genes that can regulate cell wall rigidity or cause changes in GA metabolism through interactors such as HAD9.

LD-transpeptidation is crucial for fitness and polar growth in Agrobacterium tumefaciens.

Peptidoglycan (PG), a mesh-like structure which is the primary component of the bacterial cell wall, is crucial to maintain cell integrity and shape. While most bacteria rely on penicillin binding proteins (PBPs) for crosslinking, some species also employ LD-transpeptidases (LDTs). Unlike PBPs, the essentiality and biological functions of LDTs remain largely unclear. The Hyphomicrobiales order of the Alphaproteobacteria, known for their polar growth, have PG which is unusually rich in LD-crosslinks, suggesting that LDTs may play a more significant role in PG synthesis in these bacteria. Here, we investigated LDTs in the plant pathogen Agrobacterium tumefaciens and found that LD-transpeptidation, resulting from at least one of 14 putative LDTs present in this bacterium, is essential for its survival. Notably, a mutant lacking a distinctive group of 7 LDTs which are broadly conserved among the Hyphomicrobiales exhibited reduced LD-crosslinking and tethering of PG to outer membrane β-barrel proteins. Consequently, this mutant suffered severe fitness loss and cell shape rounding, underscoring the critical role played by these Hyphomicrobiales-specific LDTs in maintaining cell wall integrity and promoting elongation. Tn-sequencing screens further revealed non-redundant functions for A. tumefaciens LDTs. Specifically, Hyphomicrobiales-specific LDTs exhibited synthetic genetic interactions with division and cell cycle proteins, and a single LDT from another group. Additionally, our findings demonstrate that strains lacking all LDTs except one displayed distinctive phenotypic profiles and genetic interactions. Collectively, our work emphasizes the critical role of LD-crosslinking in A. tumefaciens cell wall integrity and growth and provides insights into the functional specialization of these crosslinking activities.

Political stability in authoritarian regimes: the case of Central Asia

ABSTRACT Existing research indicates that political stability is a prerequisite for good governance and economic development in Central Asia. All five countries in the region are authoritarian regimes but it is unclear which factors impact on political stability. Using data for the period 2002–2022, this paper examines the variables which make a significant contribution to political stability and finds that the rule of law, personalist rule, a free media, freedom of assembly, political polarization and gross domestic product (GDP) growth, respectively have a positive effect on political stability while government accountability, exclusions by social group and civil society participation have a negative effect. Some of the findings are at odds with other studies on autocratic regimes, illustrating the importance of geo-political context.

Mrlac1, an extracellular laccase, is required for conidial morphogenesis as well as the well adaptability in field of Metarhizium rileyi

Acting as an extremely promising fungal pesticide, Metarhizium rileyi exhibits robust insecticidal activity against Lepidoptera pests, particularly the larvae. Though there is a slight delay in efficacy, biopesticides offer salient advantages over traditional chemical pesticide especially in environmental safety, cyclic infection and resistant inhibition. In this study, an exterior T-DNA was randomly inserted into the genome of M. rileyi, resulting in the acquisition of a mutant strain that displayed a colour transition from green to yellow within its conidia. The disruption of Mrlac1, a laccase, has been confirmed to attribute to the epigenetic alterations. Mrlac1 is a secreted protein harboring an N-terminal signaling peptide that undergoes in vivo synthesis and accumulates on the cell wall of M. rileyi. Targeted knock-out mutant exhibited alterations not just in conidia coloration, but significantly diminished capacity to withstand external stressors, particularly non-biological factors such as high humidity, Congo red exposure, and UV radiation. The disruptant suffered a constraint on hyphal polar growth, alteration in conidial surface structure, as well as noticeable increase in adhesion forces between conidia, the core infection factors. There is a remarkable diminution in virulence of Mrlac1 deletion variant against larvae of Spodoptera litura by topical inoculation, but not hemolymph injection. Our findings suggest that Mrlac1 acts as a positive regulator in the normal morphogenesis of fungal conidia, encompassing pigment production, inter-conidia adhesion, and conidial cell wall integrity, while the preservation of these structures holds paramount importance for the survival and infection of M. rileyi in the field.

Blocking M2-Like Macrophage Polarization Using Decoy Oligodeoxynucleotide-Based Gene Therapy Prevents Immune Evasion for Pancreatic Cancer Treatment.

M2-like macrophages exhibit immunosuppressive activity and promote pancreatic cancer progression. Reactive oxygen species (ROS) affect macrophage polarization; however, the mechanism remains unclear. This study aimed to elucidate the underlying molecular basis and design a gene therapy to inhibit M2-like polarization. Microarray analysis and immunofluorescence staining were performed in M1-like and M2-like macrophages to ascertain the expression of CYBB, a major intracellular ROS source. Coculture assay and syngeneic orthotopic pancreatic cancer mice models were used to study the mechanism of M2-like skewing. Decoy oligodeoxynucleotides (ODNs) were designed to manipulate CYBB transcription to inhibit M2-like polarization and control tumor growth. Lipopolysaccharide treatment polarized U937 cells to M1-like macrophages in which CYBB expression was increased. In contrast, coculture with PANC-1 cells induced M2-like polarization in U937 cells with CYBB downregulation. High CD204 M2-like expression in combination with low CYBB expression was associated with the worst prognosis in patients with pancreatic cancer. STAT6 and HDAC2 in U937 cells were activated by cancer cell-derived IL4 after coculture and then bound to the CYBB promoter to repress CYBB expression, resulting in M2-like polarization. Diphenyleneiodonium, 8λ³-iodatricyclo[7.4.0.02,⁷]trideca-1(13),2,4,6,9,11-hexaen-8-ylium chloride that inhibits ROS production could block this action. Knockdown of STAT6 and HDAC2 also inhibited M2-like polarization and maintained the M1-like phenotype of U937 cells after coculture. Decoy ODNs interrupting the binding of STAT6 to the CYBB promoter counteracted M2-like polarization and tumor growth and triggered antitumor immunity in vivo. Gene therapy using STAT6-CYBB decoy ODNs can inhibit M2-like polarization, representing a potential therapeutic tool for pancreatic cancer.

Affective polarization is uniformly distributed across American States.

US partisans view each other with increasing negativity. While many attribute the growth of such affective polarization to nationally cross-cutting forces, such as ideological partisan sorting or access to partisan media, others emphasize the effects of contextual and institutional forces. For the first time, we introduce and explore data sufficiently granular to fully map the extent of partisan animosity across the US states. With a massive, nationally representative survey we find that, counter to expectations, variation in affective polarization across states is relatively small, and is instead largely a function of individual-level attitudinal (but not demographic) characteristics. While elections pit regions of the country against others, our results suggest affective polarization is a national, not regional, problem, requiring national interventions.

Long-run trends in partisan polarization of climate policy-relevant attitudes across countries

ABSTRACT We summarize long-run trends in partisan polarization of voters’ climate policy-relevant attitudes across 36 countries and multiple decades (1993–2020). We find substantial growth in partisan polarization of these attitudes in the US, other Anglophone countries and much of Western Europe, but not elsewhere. Comparing Western European to Anglophone countries, partisan polarization is more prominent on different climate policy-relevant attitudes, and primarily involves supporters of different party types. Observed partisan polarization patterns are not well explained by changes in either linkage to economic ideology or levels of general societal disagreement on climate policy-relevant questions. Growing partisan polarization does not generally reflect all partisan groups becoming more accepting of climate reform yet diverging because of differing rates of change. Instead, what disagreements there are on these matters have become increasingly tied to party support. Our findings highlight the increasing difficulty of achieving sustained political consensus for effective climate reform across many countries.

MmpL3, Wag31, and PlrA are involved in coordinating polar growth with peptidoglycan metabolism and nutrient availability.

This study is performed in Mycobacterium smegmatis, which is used as a model to understand the basic physiology of pathogenic mycobacteria such as Mycobacterium tuberculosis. In this work, we examine the function and regulation of three proteins involved in regulating cell wall elongation in mycobacterial cells, which occurs at the cell tips or poles. We find that Wag31, a regulator of polar elongation, works partly through the regulation of MmpL3, a transporter of cell wall constituents and an important drug target. Our work suggests that, beyond its transport function, MmpL3 has another function in controlling cell wall synthesis broadly in response to stress.

Actin cytoskeleton and plasma membrane aquaporins are involved in different drought response of Arabidopsis rhd2 and der1 root hair mutants

Actin cytoskeleton and reactive oxygen species are principal determinants of root hair polarity and tip growth. Loss of function in RESPIRATORY BURST OXIDASE HOMOLOG C/ROOT HAIR DEFECTIVE 2 (AtRBOHC/RHD2), an NADPH oxidase emitting superoxide to the apoplast, and in ACTIN 2, a vegetative actin isovariant, in rhd2-1 and der1-3 mutants, respectively, lead to similar defects in root hair formation and elongation Since early endosome-mediated polar localization of AtRBOHC/RHD2 depends on actin cytoskeleton, comparing the proteome-wide consequences of both mutations might be of eminent interest. Therefore, we employed a differential proteomic analysis of Arabidopsis rhd2-1 and der1-3 mutants. Both mutants exhibited substantial alterations in abundances of stress-related proteins. Notably, plasma membrane (PM)-localized PIP aquaporins showed contrasting abundance patterns in the mutants compared to wild-types. Drought-responsive proteins were mostly downregulated in rhd2-1 but upregulated in der1-3. Proteomic data suggest that opposite to der1-3, altered vesicular transport in rhd2-1 mutant likely contributes to the deregulation of PM-localized proteins, including PIPs. Moreover, lattice light sheet microscopy revealed reduced actin dynamics in rhd2-1 roots, a finding contrasting with previous reports on der1-3 mutant. Phenotypic experiments demonstrated a drought stress susceptibility in rhd2-1 and resistance in der1-3. Thus, mutations in AtRBOHC/RHD2 and ACTIN2 cause similar root hair defects, but they differently affect the actin cytoskeleton and vesicular transport. Reduced actin dynamics in rhd2-1 mutant is accompanied by alteration of vesicular transport proteins abundance, likely leading to altered protein delivery to PM, including aquaporins, thereby significantly affecting drought stress responses.

Exploring the Polarization of American Elites Based on the Analyses of Candidates’ Statements During the 2020 Presidential Election

ABSTRACT The article consists of three parts. The first contains a theoretical analysis of the phenomenon of US political polarization and discusses the main approaches to its explanation, primarily through the prism of the influence of political elites. The authors note a logical contradiction in the existing concepts, which postulate the existence of an “asymmetry” in the influence of elites on polarization in the United States, arguing that the contribution of the Republicans is more destructive than the contribution of representatives of the Democratic Party. The authors find the growth of political polarization, regardless of party preferences (while noting the importance of elite behavior as one of the central factors of political polarization). The second part examines the phenomenon of affective (or emotional polarization), based on the socio-psychological rejection of representatives of an alien political camp. Based on the results of a network analysis of a two-modal network consisting of pre-election messages and topics selected by the authors themselves, the author notes that all candidates, without exception, are prone to emotional affect as part of their election campaign. The third part is devoted to the study of positional (or ideological) polarization, in which the author, on the basis of Latent Dirichlet Allocation analysis, divides the corpus of campaign messages of candidates into separate topics and, through a comparative analysis, finds a significant distance from “bipartisan” topics (i.e. from the political center) among all candidates.

Effect of pyriofenone on the infection processes and cytological features of Blumeria graminis on wheat leaves

Pyriofenone demonstrates outstanding efficacy in controlling powdery mildew. We investigated the impact of pyriofenone on the infection processes and cytological features of Blumeria graminis f. sp. tritici on wheat leaves. The preventive application of pyriofenone before inoculation did not inhibit conidial germination but effectively suppressed both appressorial and haustorial formation. Notably, haustorial formation was effectively inhibited, resulting in the complete suppression of successive lesion development and sporulation. Curative application of pyriofenone after inoculation also inhibited lesion expansion and sporulation. Furthermore, it had considerable impact on the morphogenesis of powdery mildew fungus. We observed multi-formed secondary appressoria, shrunken or bifurcated hyphae, abnormal conidiophores, and clubbed conidia-like structures. Subsequently, we employed a histochemical approach to analyze the localization of essential components for the polar growth of fungal hyphae. Pyriofenone induced mislocalization of the actin cytoskeleton, β-glucan and cytoplasmic vesicles, although it did not affect tubulin orientation.