Protein Disorder in Plant Stress Adaptation: From Late Embryogenesis Abundant to Other Intrinsically Disordered Proteins.

Global climate change has caused severe abiotic and biotic stresses, affecting plant growth and food security. The mechanical understanding of plant stress responses is critical for achieving sustainable agriculture. Intrinsically disordered proteins (IDPs) are a group of proteins without unique three-dimensional structures. The environmental sensitivity and structural flexibility of IDPs contribute to the growth and developmental plasticity for sessile plants to deal with environmental challenges. This article discusses the roles of various disordered proteins in plant stress tolerance and resistance, describes the current mechanistic insights into unstructured proteins such as the disorder-to-order transition for adopting secondary structures to interact with specific partners (i.e., cellular membranes, membrane proteins, metal ions, and DNA), and elucidates the roles of liquid-liquid phase separation driven by protein disorder in stress responses. By comparing IDP studies in animal systems, this article provides conceptual principles of plant protein disorder in stress adaptation, reveals the current research gaps, and advises on the future research direction. The highlighting of relevant unanswered questions in plant protein disorder research aims to encourage more studies on these emerging topics to understand the mechanisms of action behind their stress resistance phenotypes.

Microtubule Regulation in Plants: From Morphological Development to Stress Adaptation.

Microtubules (MTs) are essential elements of the eukaryotic cytoskeleton and are critical for various cell functions. During cell division, plant MTs form highly ordered structures, and cortical MTs guide the cell wall cellulose patterns and thus control cell size and shape. Both are important for morphological development and for adjusting plant growth and plasticity under environmental challenges for stress adaptation. Various MT regulators control the dynamics and organization of MTs in diverse cellular processes and response to developmental and environmental cues. This article summarizes the recent progress in plant MT studies from morphological development to stress responses, discusses the latest techniques applied, and encourages more research into plant MT regulation.

Comparison of Neoadjuvant Chemotherapy Efficiency in Advanced Ovarian Cancer Patients Treated With Paclitaxel Plus Carboplatin and Intraperitoneal Bevacizumab vs. Paclitaxel With Carboplatin.

Objective: This study evaluated the role of neoadjuvant chemotherapy (NACT) with bevacizumab intraperitoneal perfusion in advanced ovarian cancer (AOC). Methods: In this study, 80 patients with advanced epithelial ovarian cancer (stage IIIc or IV) who received NACT at the Central Hospital of Zhuzhou between February 2019 and October 2020 were enrolled. Patients were randomized to receive paclitaxel plus carboplatin (TC) or TC plus intraperitoneal perfusion of bevacizumab (TCB). The effect of chemotherapy was assessed following two cycles of chemotherapy. Cancer antigen 125 (CA125), tumor size, ascites volume, bleeding volume, duration of operation, surgical satisfaction rate, complication rate, and residual tumor were assessed to monitor response to chemotherapy. Results: Treatment with TCB regimen significantly reduced serum levels of CA125 and ascites volume (p < 0.001). Meanwhile, the TCB group had significantly lower intraoperative blood loss and shorter operation time (p < 0.001). Most importantly, patients treated with TCB regimen had a higher surgical satisfaction rate (p < 0.01). Moreover, the incidence of postoperative wound infection, hypoproteinemia, abdominal distension, and fever was lower in the TCB group compared with the TC group. Assessment of adverse reactions during chemotherapy showed no severe complications between the two groups. Conclusions: The results demonstrated that the TCB regimen is superior to the TC regimen alone in the treatment of AOC. These findings could help improve the surgical satisfaction rate, provide more effective treatment strategies to prolong progression-free survival and reduce postoperative complications, and promote surgical recovery in AOC.

Molecular design and biological activity analysis of antimicrobial peptide RIKL / 生物工程学报

Natural antimicrobial peptides have strong bactericidal activities. An obstacle of the development of antimicrobial peptides resides in the difficulty of developing peptides with high biocompatibility. In this study, molecular dynamics analysis was employed to assess the structural characteristics and biological activities of peptides. A (RXKY)2(YRY)2 structure was used as a template to design an antimicrobial peptide RIKL of high-efficiency and low-toxicity, where X represents Ile and Y represents Leu. The secondary structure of the antimicrobial peptide was detected by circular dichroism (CD), and the structures of RIKL in water and in POPC/POPG membrane environment were measured using molecular dynamics. The biological activity of RIKL was further studied by assessing its antimicrobial activity, hemolytic activity, eukaryotic cytotoxicity, and salt ion stability. CD results showed that RIKL presented an α-helical structure in a simulated bacterial membrane environment. Molecular dynamics simulation predicted that the secondary structure of RIKL could be partly retained in water and POPG environment, while this secondary structure was weakened in the POPC environment. Antimicrobial test suggested that RIKL had high antimicrobial activities, and the geometric mean of the Minimum Inhibitory Concentration (MIC) was 3.1 μmol/L. The hemolysis indicated that RIKL had no hemolytic activity within the detection range, and cytotoxicity test suggested the cytotoxicity of RIKL was low. Stability test showed that RIKL maintained antimicrobial activities under different pH, serum concentrations and salt environments. Based on the above results, RIKL has high cell selectivity and has the potential as a highly effective antibacterial drug.

The effects of hinge structure on the biological activity of antimicrobial peptides and its application in molecular design: a review / 生物工程学报

The hinge structure, also known as hinge region or bend, is a special structure found in some antimicrobial peptides. Most studies on antimicrobial peptides focused on the standard secondary structure of α-helix and β-sheet, while the hinge structure and its functions were rarely studied. The hinge structure confers the antimicrobial peptides an improved structural flexibility, which may promote their disruptive effect on bacterial membrane or their binding efficiency to the intracellular targets, thus resulting in a higher antibacterial activity. Meanwhile, the hinge structure may reduce the structural rigidity, which may eliminate the cytotoxicity of antimicrobial peptides to eukaryotic cells. This article reviews the structural characteristics of the hinge structure, its effects on the biological activity of antimicrobial peptides and application in the molecular design, with the aim to provide a reference for the design and development of new antimicrobial peptides.

Application of supramolecular peptide self-assembly in biomedicine / 生物工程学报

In recent years, peptide self-assembly has received much attention because of its ability to form regular and ordered structures with diverse functions. Self-assembled peptides can form aggregates with defined structures under specific conditions. They show different characteristics and advantages (e.g., good biocompatibility and high stability) compared with monomeric peptides, which form the basis for potential application in the fields of drug delivery, tissue engineering, and antiseptics. In this paper, the molecular mechanisms, types and influencing factors of forming self-assembled peptides were reviewed, followed by introducing the latest advances on fibrous peptide hydrogels and self-assembled antimicrobial peptides. Furthermore, the challenges and perspectives for peptide self-assembly technology were discussed.

An Intrinsically Disordered Protein Interacts with the Cytoskeleton for Adaptive Root Growth under Stress.

Intrinsically disordered proteins function as flexible stress modulators in vivo through largely unknown mechanisms. Here, we elucidated the mechanistic role of an intrinsically disordered protein, REPETITIVE PRO-RICH PROTEIN (RePRP), in regulating rice (Oryza sativa) root growth under water deficit. With nearly 40% Pro, RePRP is induced by water deficit and abscisic acid (ABA) in the root elongation zone. RePRP is sufficient and necessary for repression of root development by water deficit or ABA. We showed that RePRP interacts with the highly ordered cytoskeleton components actin and tubulin both in vivo and in vitro. Binding of RePRP reduces the abundance of actin filaments, thus diminishing noncellulosic polysaccharide transport to the cell wall and increasing the enzyme activity of Suc synthase. RePRP also reorients the microtubule network, which leads to disordered cellulose microfibril organization in the cell wall. The cell wall modification suppresses root cell elongation, thereby generating short roots, whereas increased Suc synthase activity triggers starch accumulation in "heavy" roots. Intrinsically disordered proteins control cell elongation and carbon reserves via an order-by-disorder mechanism, regulating the highly ordered cytoskeleton for development of "short-but-heavy" roots as an adaptive response to water deficit in rice.

Rice Big Grain 1 promotes cell division to enhance organ development, stress tolerance and grain yield.

Grain/seed yield and plant stress tolerance are two major traits that determine the yield potential of many crops. In cereals, grain size is one of the key factors affecting grain yield. Here, we identify and characterize a newly discovered gene Rice Big Grain 1 (RBG1) that regulates grain and organ development, as well as abiotic stress tolerance. Ectopic expression of RBG1 leads to significant increases in the size of not only grains but also other major organs such as roots, shoots and panicles. Increased grain size is primarily due to elevated cell numbers rather than cell enlargement. RBG1 is preferentially expressed in meristematic and proliferating tissues. Ectopic expression of RBG1 promotes cell division, and RBG1 co-localizes with microtubules known to be involved in cell division, which may account for the increase in organ size. Ectopic expression of RBG1 also increases auxin accumulation and sensitivity, which facilitates root development, particularly crown roots. Moreover, overexpression of RBG1 up-regulated a large number of heat-shock proteins, leading to enhanced tolerance to heat, osmotic and salt stresses, as well as rapid recovery from water-deficit stress. Ectopic expression of RBG1 regulated by a specific constitutive promoter, GOS2, enhanced harvest index and grain yield in rice. Taken together, we have discovered that RBG1 regulates two distinct and important traits in rice, namely grain yield and stress tolerance, via its effects on cell division, auxin and stress protein induction.

Kinetic analysis and structural studies of a high-efficiency laccase from Cerrena sp. RSD1.

A high-efficiency laccase, DLac, was isolated from Cerrena sp. RSD1. The kinetic studies indicate that DLac is a diffusion-limited enzyme. The crystal structure of DLac was determined to atomic resolution, and its overall structure shares high homology to monomeric laccases, but displays unique substrate-binding loops from those in other laccases. The substrate-binding residues with small side chain and the short substrate-binding loop IV broaden the substrate-binding cavity and may facilitate large substrate diffusion. Unlike highly glycosylated fungal laccases, the less-glycosylated DLac contains one highly conserved glycosylation site at N432 and an unique glycosylation site at N468. The N-glycans stabilize the substrate-binding loops and the protein structure, and the first N-acetylglucosamine is crucial for the catalytic efficiency. Additionally, a fivefold increase in protein yield is achieved via the submerged culture method for industrial applications. DATABASE: The atomic coordinates of the structure of DLac from Cerrena sp. RSD1 and structural factors have been deposited in the RCSB Protein Data Bank (PDB ID: 5Z1X).

Arabidopsis ACYL-COA-BINDING PROTEIN1 interacts with STEROL C4-METHYL OXIDASE1-2 to modulate gene expression of homeodomain-leucine zipper IV transcription factors.

Fatty acids (FAs) and sterols constitute building blocks of eukaryotic membranes and lipid signals. Co-regulation of FA and sterol synthesis is mediated by sterol regulatory element-binding proteins in animals but remains elusive in plants. We reported recently that Arabidopsis ACYL-COA-BINDING PROTEIN1 (ACBP1) modulates sterol synthesis via protein-protein interaction with STEROL C4-METHYL OXIDASE1-1 (SMO1-1). Herein, ACBP1 was demonstrated to co-express and interact with SMO1-2 by yeast two-hybrid, co-localization, pull-down, co-immunoprecipitation and ß-glucuronidase assays. SMO1-2 silenced in acbp1 was used in phenotyping, GC-MS and expression profiling. ACBP1 co-expressed with SMO1-2 in embryo sacs, pollen and trichomes, corroborating with cooperative tissue-specific functions unseen with SMO1-1. SMO1-2 silencing in acbp1 impaired seed development, male and female gamete transmission, and pollen function. Genes encoding homeodomain-leucine zipper IV transcription factors (HDG5, HDG10, HDG11 and GLABRA2), which potentially bind phospholipids/sterols, were transcribed aberrantly. GLABRA2 targets (MYB23, MUM4 and PLDα1) were misregulated, causing glabra2-resembling trichome, seed coat mucilage and oil-accumulating phenotypes. Together with altered sterol and FA compositions upon ACBP1 mutation and/or SMO1-2 silencing, ACBP1-SMO1 interaction appears to mediate homeostatic co-regulation of FAs and sterols, which serve as lipid modulators for gene expression of homeodomain-leucine zipper IV transcription factors.

Knockdown of lncRNA GHET1 suppresses cell proliferation, invasion and LATS1/YAP pathway in non small cell lung cancer.

BACKGROUND: The aim in this study was to explore the role of long non-coding RNA GHET1 in development of non small cell lung cancer (NSCLC). METHODS: LncRNA GHET1 expression levels were analyzed by qRT-PCR in tumor tissues and adjacent normal tissues in NSCLC. Measuring the cell proliferation and invasion abilities by CCK8, cell colony formation and transwell invasion assays. Relative protein expression was analyzed by western blot assays. RESULTS: Expression of lncRNA GHET1 was notably higher in NSCLC tissues compared with adjacent normal tissues by using qRT-PCR analyses. Higher lncRNA GHET1 expression associated with lymph node metastasis, TNM stage and showed poor outcome in NSCLC patients. Knockdown of lncRNA GHET1 suppressed cell proliferation and invasion capacity and Epithelial-Mesenchymal Transition (EMT) phenomenon of NSCLC cells. Moreover, we demonstrated that knockdown of lncRNA GHET1 suppresses LATS1/YAP pathway signaling pathway by downregulating YAP1 expression in NSCLC cells. CONCLUSIONS: GHET1 predicted a poor outcome and acted as a tumor-promoting gene in NSCLC. Thus, inhibition of GHET1 may be a potential target of NSCLC treatment.

Ectopic Expression of WINDING 1 Leads to Asymmetrical Distribution of Auxin and a Spiral Phenotype in Rice.

Ectopic expression of the rice WINDING 1 (WIN1) gene leads to a spiral phenotype only in shoots but not in roots. Rice WIN1 belongs to a specific class of proteins in cereal plants containing a Bric-a-Brac/Tramtrack/Broad (BTB) complex, a non-phototropic hypocotyl 3 (NPH3) domain and a coiled-coil motif. The WIN1 protein is predominantly localized to the plasma membrane, but is also co-localized to plasmodesmata, where it exhibits a punctate pattern. It is observed that WIN1 is normally expressed in roots and the shoot-root junction, but not in the rest of shoots. In roots, WIN1 is largely localized to the apical and basal sides of cells. However, upon ectopic expression, WIN1 appears on the longitudinal sides of leaf sheath cells, correlated with the appearance of a spiral phenotype in shoots. Despite the spiral phenotype, WIN1-overexpressing plants exhibit a normal phototropic response. Although treatments with exogenous auxins or a polar auxin transport inhibitor do not alter the spiral phenotype, the excurvature side has a higher auxin concentration than the incurvature side. Furthermore, actin filaments are more prominent in the excurvature side than in the incurvature side, which correlates with cell size differences between these two sides. Interestingly, ectopic expression of WIN1 does not cause either unequal auxin distribution or actin filament differences in roots, so a spiral phenotype is not observed in roots. The action of WIN1 appears to be different from that of other proteins causing a spiral phenotype, and it is likely that WIN1 is involved in 1-N-naphthylphthalamic acid-insensitive plasmodesmata-mediated auxin transport.

Acyl-CoA-Binding Protein ACBP1 Modulates Sterol Synthesis during Embryogenesis.

Fatty acids (FAs) and sterols are primary metabolites that exert interrelated functions as structural and signaling lipids. Despite their common syntheses from acetyl-coenzyme A, homeostatic cross talk remains enigmatic. Six Arabidopsis (Arabidopsis thaliana) acyl-coenzyme A-binding proteins (ACBPs) are involved in FA metabolism. ACBP1 interacts with PHOSPHOLIPASE Dα1 and regulates phospholipid composition. Here, its specific role in the negative modulation of sterol synthesis during embryogenesis is reported. ACBP1, likely in a liganded state, interacts with STEROL C4-METHYL OXIDASE1-1 (SMO1-1), a rate-limiting enzyme in the sterol pathway. Proembryo abortion in the double mutant indicated that the ACBP1-SMO1-1 interaction is synthetic lethal, corroborating with their strong promoter activities in developing ovules. Gas chromatography-mass spectrometry revealed quantitative and compositional changes in FAs and sterols upon overexpression or mutation of ACBP1 and/or SMO1-1 Aberrant levels of these metabolites may account for the downstream defect in lipid signaling. GLABRA2 (GL2), encoding a phospholipid/sterol-binding homeodomain transcription factor, was up-regulated in developing seeds of acbp1, smo1-1, and ACBP1+/-smo1-1 in comparison with the wild type. Consistent with the corresponding transcriptional alteration of GL2 targets, high-oil, low-mucilage phenotypes of gl2 were phenocopied in ACBP1+/-smo1-1 Thus, ACBP1 appears to modulate the metabolism of two important lipid classes (FAs and sterols) influencing cellular signaling.

Internal image anti-idiotypic antibody: A new strategy for the development a new category of prolactin receptor (PRLR) antagonist.

Over the past decades, a number of prolactin receptor (PRLR) antagonists have been developed, which can be divided into two categories, PRLR analogue and anti-PRLR antibody. However, until now, there have been no commercially available PRLR antagonists. Here, we described a new approach for the preparation of PRLR antagonist, namely internal image anti-idiotypic antibody strategy. The hybridoma technique was used to generate anti-idiotypic antibodies to PRL. Competitive ELISA, competitive receptor-binding analysis and immunofluorescence assay (IFA) were then used to screen and characterize anti-idiotypic antibodies to PRL. One internal image anti-idiotypic antibody, termed MG7, was obtained. A series of experiments demonstrated that MG7 behaved as a typical internal image anti-idiotypic antibody (Ab2ß). MG7 exhibited effective antagonistic activity, which not only inhibited PRL binding to PRLR in a dose-dependent manner but also inhibited PRLR-mediated intracellular signalling. Furthermore, MG7 also blocked Nb2 cell proliferation induced by PRL. The current study suggests that MG7 has the potential application in the PRL/PRLR-related studies in future. In addition, this work also suggests that the internal image anti-idiotypic antibody may represent a novel strategy for the development of PRLR antagonist.

[Analysis of Malaria Endemic Situation in the Joint Malaria Control Zone of Guizhou and Guangxi Provinces from 2012 to 2013].

Information on the endemic situation of malaria in the joint malaria control zone of Guizhou and Guangxi Provinces from 2012 to 2013 was collected. Blood test results from fever patients and the healthy population were obtained. The spatiotemperal and occupational distributions of malaria cases were analyzed. During 2012-2013, blood tests were performed in 253 606 local residents and 11 212 returning residents in the joint area, as well as in 19 843 migrants from outside the area, resulting in discovery of 30 Plasmodium-infected cases only in the returning residents. All the 30 cases were imported from abroad, most of whom were electricity workers returning from the Africa. Among them, 28 cases were reported in 6 counties in Guangxi, and 2 in 2 counties/cities in Guizhou.

Lithium chloride's inhibition of 3T3-L1 cell differentiation by regulating the Wnt/ß-catenin pathway and enhancing villin 2 expression.

The aim of this study is to reveal the relation among villin 2, Wnt/ß-catenin, and adipogenesis by adding appropriate lithium chloride (LiCl). The study comprises three parts: the selection of LiCl concentration, the effect of LiCl on adipocyte differentiation during and after differentiation induction. By comprehensively analyzing the results of the experiments, we proved that LiCl can inhibit adipocyte differentiation and enhance villin 2 and ß-catenin expressions not only during differentiation induction but also after it. Moreover, villin 2 has a significant impact on ß-catenin. We suggest that villin 2 may participate in Wnt/ß-catenin signaling.

Selenium Deficiency Affects the mRNA Expression of Inflammatory Factors and Selenoprotein Genes in the Kidneys of Broiler Chicks.

The aim of this study was to investigate the influence of Se deficiency on the transcription of inflammatory factors and selenoprotein genes in the kidneys of broiler chicks. One hundred fifty 1-day-old broiler chicks were randomly assigned to two groups fed with either a low-Se diet (L group, 0.033 mg/kg Se) or an adequate Se diet (C group, 0.2 mg/kg Se). The levels of uric acid (UA) and creatinine (Cr) in the serum and the mRNA levels of 6 inflammatory factors and 25 selenoprotein genes in the kidneys were measured as the clinical signs of Se deficiency occurred at 20 days old. The results indicated that the contents of UA and Cr in the serum increased in L group (p < 0.05), and the mRNA levels of the inflammatory factors (NF-κB, iNOS, COX-2, and TNF-α) increased in L group (p < 0.05). Meanwhile, the mRNA levels of PTGEs and HO-1 were not changed. In addition, 25 selenoprotein transcripts displayed ubiquitous expression in the kidneys of the chicks. The mRNA levels of 14 selenoprotein genes (Dio1, Dio2, GPx3, Sepp1, SelH, SelI, SelK, Sepn1, SelO, SelW, Sep15, SelT, SelU, and SelS) decreased, and 9 selenoprotein genes (GPx1, GPx2, GPx4, SelPb, Txnrd1, Txnrd2, Txnrd3, SPS2, and SelM) increased in L group (p < 0.05), but the Dio3 and Sepx1 mRNA levels did not change. The results indicated that Se deficiency resulted in kidney dysfunction, activation of the NF-κB pathway, and a change in selenoprotein gene expression. The changes of inflammatory factor and selenoprotein gene expression levels were directly related to the abnormal renal functions induced by Se deficiency.

The Arabidopsis cytosolic Acyl-CoA-binding proteins play combinatory roles in pollen development.

In Arabidopsis, six acyl-CoA-binding proteins (ACBPs) have been identified and they have been demonstrated to function in plant stress responses and development. Three of these AtACBPs (AtACBP4-AtACBP6) are cytosolic proteins and all are expressed in floral organs as well as in other tissues. The roles of cytosolic AtACBPs in floral development were addressed in this study. To this end, a T-DNA insertional knockout mutant of acbp5 was characterized before use in crosses with the already available acbp4 and acbp6 T-DNA knockout mutants to examine their independent and combinatory functions in floral development. The single-gene knockout mutations did not cause any significant phenotypic changes, while phenotypic deficiencies affecting siliques and pollen were observed in the double mutants (acbp4acbp6 and acbp5acbp6) and the acbp4acbp5acbp6 triple mutant. Vacuole accumulation in the acbp4acbp6, acbp5acbp6 and acbp4acbp5acbp6 pollen was the most severe abnormality occurring in the double and triple mutants. Furthermore, scanning electron microscopy and transmission electron microscopy revealed exine and oil body defects in the acbp4acbp5acbp6 mutant, which also displayed reduced ability in in vitro pollen germination. Transgenic Arabidopsis expressing ß-glucuronidase (GUS) driven from the various AtACBP promoters indicated that AtACBP6pro::GUS expression overlapped with AtACBP4pro::GUS expression in pollen grains and with AtACBP5pro::GUS expression in the microspores and tapetal cells. Taken together, these results suggest that the three cytosolic AtACBPs play combinatory roles in acyl-lipid metabolism during pollen development.