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1.
Food Chem ; 367: 130708, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352692

RESUMO

In this study, we explored structural differences of five commercial samples of yeast ß-glucan. Samples were assayed for their ß-glucan content and the yeast storage carbohydrate, glycogen. The ß-glucan content ranged from 74% to 86%, the glycogen content varied from 0 to 20%. The linkage pattern of each sample was measured by the partially methylated alditol acetate method. This method showed that the samples varied from 1.9% to 9.2% branching. The side chain length distribution for each sample was analyzed by an alkaline degradation assay followed by ion chromatography. The side length distributions of the samples were shown to be similar. The samples were also analyzed by FT-IR and 1HNMR spectroscopy but it was difficult to derive quantitative differences in the samples by these methods. Our findings confirm that each proprietary source of yeast ß-glucan has a unique purity profile, branching, and linkage patterns that determine the chemical structure and composition.


Assuntos
Saccharomyces cerevisiae , beta-Glucanas , Parede Celular , Glucanos , Saccharomyces cerevisiae/genética , Espectroscopia de Infravermelho com Transformada de Fourier
2.
J Cell Sci ; 135(5)2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33912961

RESUMO

Septins colocalize with membrane sterol-rich regions and facilitate recruitment of cell wall synthases during wall remodeling. We show that null mutants missing an Aspergillus nidulans core septin present in hexamers and octamers (ΔaspAcdc11, ΔaspBcdc3 or ΔaspCcdc12) are sensitive to multiple cell wall-disturbing agents that activate the cell wall integrity MAPK pathway. The null mutant missing the octamer-exclusive core septin (ΔaspDcdc10) showed similar sensitivity, but only to a single cell wall-disturbing agent and the null mutant missing the noncore septin (ΔaspE) showed only very mild sensitivity to a different single agent. Core septin mutants showed changes in wall polysaccharide composition and chitin synthase localization. Mutants missing any of the five septins resisted ergosterol-disrupting agents. Hexamer mutants showed increased sensitivity to sphingolipid-disrupting agents. Core septins mislocalized after treatment with sphingolipid-disrupting agents, but not after ergosterol-disrupting agents. Our data suggest that the core septins are involved in cell wall integrity signaling, that all five septins are involved in monitoring ergosterol metabolism, that the hexamer septins are required for sphingolipid metabolism and that septins require sphingolipids to coordinate the cell wall integrity response.


Assuntos
Aspergillus nidulans , Septinas , Aspergillus nidulans/metabolismo , Parede Celular/metabolismo , Metabolismo dos Lipídeos , Septinas/genética , Septinas/metabolismo , Esfingolipídeos/metabolismo
3.
Food Chem ; 372: 131171, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34601416

RESUMO

The genus Pleurotus, namely oyster mushroom, is widely cultivated and consumed worldwide. Cap color is an important commercial trait for oyster mushroom. Diverse color is determined by various pigment constituents. However, the pigments of oyster mushrooms are still ambiguous. In this study, we extracted and identified pigments of oyster mushroom species with black, yellow and pink cap color. The extracted pigments appearing the three color types correspondingly to the cap color, which were all identified as melanin using a panel of spectroscopic and physical/imaging techniques. Nevertheless, HPLC and elemental analysis indicated that the melanin in oyster mushrooms was actually a mixture of eumelanin and phaeomelanin. Differences in the quantities and relative proportions of eumelanin and phaeomelanin resulted in the color variation in oyster mushroom caps. Electron microscopy studies showed that the melanin units are likely located in the cell wall, as reported in other fungi. The pigments in oyster mushrooms with three different cap color were extracted and identified for the first time in this study, which provided fundamental knowledge for future studies on the mechanism of color formation in mushrooms.


Assuntos
Pleurotus , Parede Celular , Pigmentação , Pleurotus/genética , Análise Espectral
4.
Front Cell Infect Microbiol ; 11: 756206, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722342

RESUMO

The LAMMER kinase in eukaryotes is a well-conserved dual-specificity kinase. Aspergillus species cause a wide spectrum of diseases called aspergillosis in humans, depending on the underlying immune status of the host, such as allergy, aspergilloma, and invasive aspergillosis. Aspergillus fumigatus is the most common opportunistic fungal pathogen that causes invasive aspergillosis. Although LAMMER kinase has various functions in morphology, development, and cell cycle regulation in yeast and filamentous fungi, its function in A. fumigatus is not known. We performed molecular studies on the function of the A. fumigatus LAMMER kinase, AfLkhA, and reported its involvement in multiple cellular processes, including development and virulence. Deletion of AflkhA resulted in defects in colonial growth, production of conidia, and sexual development. Transcription and genetic analyses indicated that AfLkhA modulates the expression of key developmental regulatory genes. The AflkhA-deletion strain showed increased production of gliotoxins and protease activity. When conidia were challenged with alveolar macrophages, enodocytosis of conidia by macrophages was increased in the AflkhA-deletion strain, resulting from changes in expression of the cell wall genes and thus content of cell wall pathogen-associated molecular patterns, including ß-1,3-glucan and GM. While T cell-deficient zebrafish larvae were significantly susceptible to wild-type A. fumigatus infection, AflkhA-deletion conidia infection reduced host mortality. A. fumigatus AfLkhA is required for the establishment of virulence factors, including conidial production, mycotoxin synthesis, protease activity, and interaction with macrophages, which ultimately affect pathogenicity at the organismal level.


Assuntos
Aspergillus fumigatus , Padrões Moleculares Associados a Patógenos , Animais , Aspergillus fumigatus/genética , Parede Celular , Proteínas Fúngicas/genética , Humanos , Reprodução , Esporos Fúngicos , Virulência , Peixe-Zebra
5.
Plant Sci ; 313: 111059, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34763853

RESUMO

Fusarium Head Blight (FHB) and Crown Rot (FCR) are major diseases of wheat crops, causing extensive damages and mycotoxin contamination. In this work, we investigated the possibility to improve resistance to either or both diseases by combining different resistance mechanisms. To this aim, we stacked in the same wheat genotype transgenes controlling the DON-to-D3G conversion by specific UDP-glucosyltransferases (UGT) and the inhibition of cell wall degrading enzymes (CWDEs) by glycosidase inhibitors. We obtained: i) a durum wheat UGT+PMEI double-transgenic line constitutively expressing the HvUGT13248 and AcPMEI genes, coding for a barley UGT and a kiwi pectin methylesterase inhibitor, respectively; ii) a bread wheat UGT+PGIP line, expressing in floral tissues the HvUGT13248 gene and constitutively the PvPGIP2 gene, coding for a bean polygalacturonase inhibiting protein. We observed that both UGT+PMEI and UGT+PGIP plants exhibited increased resistance against Fusarium graminearum in FHB, further reducing by 10-20 % FHB symptoms as compared to the lines carrying the individual transgenes, and of up to 50 % as compared to wild-type plants. On the other hand, double-transgenic UGT+PMEI seedlings exhibited similar FCR symptoms as the UGT single transgenic line after infection with F. culmorum, indicating no contribution of the PMEI transgene to FCR resistance. This result is also supported by the inability of AcPMEI or PvPGIP2, constitutively expressed in durum wheat transgenic lines, to counteract F. graminearum in FCR. We also verified that F. graminearum produces PG and PME activity on infected wheat crown. We conclude that CWDEs inhibition combined with UGT-based DON detoxification contribute in an additive manner to limiting F. graminearum in FHB. Conversely, UGT-based DON detoxification is the only mechanism contributing to resistance observed against FCR. Indeed, the reinforcement of pectin does not enhance resistance against FCR.


Assuntos
Parede Celular/metabolismo , Resistência à Doença/genética , Fusarium/patogenicidade , Doenças das Plantas/microbiologia , Transgenes , Tricotecenos/metabolismo , Triticum/genética , Triticum/microbiologia , Produtos Agrícolas/genética , Produtos Agrícolas/microbiologia , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/genética
6.
An Acad Bras Cienc ; 93(suppl 4): e20210047, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34730621

RESUMO

The Agaricomycetes fungi produce various compounds with pharmaceutical, medicinal, cosmetic, environmental and biotechnological properties. In addition, some polysaccharides extracted from the fungal cell wall have antitumor and immunomodulatory actions. The aim of this study was to use genetic modification to transform Schizophyllum commune and identify if the phenotype observed (different from the wild type) resulted in changes of the cell wall polysaccharides. The plasmid pUCHYG-GPDGLS, which contains the Pleurotus ostreatus glucan synthase gene, was used in S. commune transformations. Polysaccharides from cell wall of wild (ScW) and mutants were compared in this study. Polysaccharides from the biomass and culture broth were extracted with hot water. One of the mutants (ScT4) was selected for further studies and, after hydrolysis/acetylation, the GLC analysis showed galactose as the major component in polysaccharide fraction from the mutant and glucose as the major monomer in the wild type. Differences were also found in the elution profiles from HPSEC and NMR analyses. From the monosaccharide composition it was proposed that mannogalactans are components of S. commune cell wall for both, wild and mutant, but in different proportions. To our knowledge, this is the first time that mannogalactans are isolated from S. commune liquid culture.


Assuntos
Schizophyllum , Parede Celular , Mutação/genética , Fenótipo , Polissacarídeos , Schizophyllum/genética
7.
BMC Genomics ; 22(1): 798, 2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34742254

RESUMO

BACKGROUND: Treatment of wheat with the phytohormones abscisic acid (ABA) and gibberellic acid (GA) has been shown to affect Fusarium head blight (FHB) disease severity. However, the molecular mechanisms underlying the elicited phenotypes remain unclear. Toward addressing this gap in our knowledge, global transcriptomic profiling was applied to the FHB-susceptible wheat cultivar 'Fielder' to map the regulatory responses effected upon treatment with ABA, an ABA receptor antagonist (AS6), or GA in the presence or absence of Fusarium graminearum (Fg) challenge. RESULTS: Spike treatments resulted in a total of 30,876 differentially expressed genes (DEGs) identified in 'Fielder' (26,004) and the Fg (4872) pathogen. Topology overlap and correlation analyses defined 9689 wheat DEGs as Fg-related across the treatments. Further enrichment analyses demonstrated that these included expression changes within 'Fielder' defense responses, cell structural metabolism, molecular transport, and membrane/lipid metabolism. Dysregulation of ABA and GA crosstalk arising from repression of 'Fielder' FUS3 was noted. As well, expression of a putative Fg ABA-biosynthetic cytochrome P450 was detected. The co-applied condition of Fg + ABA elicited further up-regulation of phytohormone biosynthesis, as well as SA and ET signaling pathways and cell wall/polyphenolic metabolism. In contrast, co-applied Fg + GA mainly suppressed phytohormone biosynthesis and signaling, while modulating primary and secondary metabolism and flowering. Unexpectedly, co-applied Fg + AS6 did not affect ABA biosynthesis or signaling, but rather elicited antagonistic responses tied to stress, phytohormone transport, and FHB disease-related genes. CONCLUSIONS: Observed exacerbation (misregulation) of classical defense mechanisms and cell wall fortifications upon ABA treatment are consistent with its ability to promote FHB severity and its proposed role as a fungal effector. In contrast, GA was found to modulate primary and secondary metabolism, suggesting a general metabolic shift underlying its reduction in FHB severity. While AS6 did not antagonize traditional ABA pathways, its impact on host defense and Fg responses imply potential for future investigation. Overall, by comparing these findings to those previously reported for four additional plant genotypes, an additive model of the wheat-Fg interaction is proposed in the context of phytohormone responses.


Assuntos
Fusarium , Parede Celular , Resistência à Doença , Perfilação da Expressão Gênica , Giberelinas , Doenças das Plantas/genética , Reguladores de Crescimento de Plantas/farmacologia , Triticum/genética
8.
Fungal Biol ; 125(11): 914-922, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34649678

RESUMO

Lectins are characterized of the carbohydrate-binding ability and play comprehensive roles in fungal physiology (e.g., defense response, development and host-pathogen interaction). Beauveria bassiana, a filamentous entomopathogenic fungus, has a lectin-like protein containing a Fruit Body_domain (BbLec1). BbLec1 could bind to chitobiose and chitin in fungal cell wall. BbLec1 proteins interacted with each other to form multimers, and translocated into eisosomes. Further, the interdependence between BbLec1 and the eisosome protein PliA was essential for stabilizing the eisosome architecture. To test the BbLec1 roles in B. bassiana, we constructed the gene disruption and complementation mutants. Notably, the BbLec1 loss resulted in the impaired cell wall in mycelia and conidia as well as conidial formation capacity. In addition, disruption of BbLec1 led to the reduced cytomembrane integrity and the enhanced sensitivity to osmotic stress. Finally, ΔBbLec1 mutant strain displayed the weakened virulence when compared with the wild-type strain. Taken together, BbLec1 traffics into eisosome and links the functionality of eisosome to development and virulence of B. bassiana.


Assuntos
Beauveria , Animais , Beauveria/genética , Parede Celular , Proteínas Fúngicas/genética , Insetos , Lectinas , Esporos Fúngicos , Virulência
9.
Appl Microbiol Biotechnol ; 105(20): 7997-8007, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34596723

RESUMO

Agaricus bisporus is the most widely cultivated edible mushroom in the world. Strain quality has an important influence on the yield of A. bisporus, with strains that exhibit aging being a common problem during cultivation. However, little is known about the aging mechanisms of A. bisporus strain. In this study, the normal A. bisporus As2796 strain was compared to the aging A. bisporus As2796Y strain (which was previously discovered during cultivation). In the aging As2796Y mycelia, the mycelial growth rate and fruiting body yield were decreased and the chitin level and cell wall thickness were increased. Additionally, intracellular vacuoles increased, there was cytoplasmic shrinkage, and the sterol level which stabilizes the cell membrane decreased, which led to cytoplasmic outflow and the exudation of a large amount of yellow water from the mycelia. Additionally, there was increased electrolyte leakage. Furthermore, gas chromatography-mass spectrometry (GC/MS) was used to profile the metabolic changes in the aging As2796Y mycelia compared to the normal As2796 mycelia. A total of 52 differential metabolites were identified (75% were downregulated and 25% were upregulated in As2796Y). The reduction of many metabolites decreased the mycelial viability and the ability to maintain cell stability. Overall, this study is the first to report on the morphologic and metabolic changes in aged A. bisporus mycelia, which will aid future research on the mechanisms underlying A. bisporus mycelial aging.Key points• Aging of Agaricus bisporus strains will greatly reduce the fruiting body yield.• Aging of Agaricus bisporus strains can significantly change the cell structure of mycelia.• Many metabolites in the mycelium of aging spawn As2796Y significantly changed.


Assuntos
Agaricus , Ascomicetos , Parede Celular , Micélio
10.
J Plant Res ; 134(6): 1155-1158, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34613490

RESUMO

Plant cell walls have multiple functions, including determining cell shape and size, cell-cell adhesion, controlling cell differentiation and growth, and promoting abiotic and biotic stress tolerance. This virtual issue introduces the physiological functions of cell walls in growth and environmental responses. The articles detail research on (1) embryogenesis and seed development, (2) vegetative growth, (3) reproductive growth, and (4) environmental responses. These articles, published in the Journal of Plant Research, will provide valuable information for future research on the function and dynamics of cell walls at various growth stages, and in response to environmental factors.


Assuntos
Desenvolvimento Vegetal , Plantas , Parede Celular , Regulação da Expressão Gênica de Plantas , Sementes , Estresse Fisiológico
11.
Planta ; 254(6): 109, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34705112

RESUMO

MAIN CONCLUSION: Differences in cell wall components between two BNF-contrasting sugarcane genotypes might result from genetic variations particular to the genotype and from the efficiency in diazotrophic bacteria association. Sugarcane is a plant of the grass family (Poaceae) that is highly cultivated in Brazil, as an important energy resource. Commercial sugarcane genotypes may be successfully associated with beneficial endophytic nitrogen-fixing bacteria, which can influence several plant metabolic pathways, such as cell division and growth, synthesis of hormones, and defense compounds. In this study, we investigated how diazotrophic bacteria associated with sugarcane plants could be involved in the regulation of cell wall formation pathways. A molecular and structural characterization of the cell wall was compared between two genotypes of sugarcane with contrasting rates of Biological Nitrogen Fixation (BNF): SP70-1143 (high BNF) and Chunee (low BNF). Differentially expressed transcripts were identified in transcriptomes generated from SP70-1143 and Chunee. Expression profiles of cellulose and lignin genes, which were more expressed in SP70-1134, and callose genes, which were more expressed in Chunee, were validated by RT-qPCR and microscopic analysis of cell wall components in tissue sections. A similar expression profile in both BNF-contrasting genotypes was observed in naturally colonized plants and in plants inoculated with G. diazotrophicus. Cell walls of the high BNF genotype have a greater cellulose content, which might contribute to increase biomass. In parallel, callose was concentrated in the vascular tissues of the low BNF genotype and could possibly represent a barrier for an efficient bacterial colonization and dissemination in sugarcane tissues. Our data show a correlation between the gene profiles identified in the BNF-contrasting genotypes and a successful association with endophytic diazotrophic bacteria.


Assuntos
Saccharum , Bactérias , Parede Celular/metabolismo , Genótipo , Fixação de Nitrogênio , Saccharum/genética
12.
PLoS Pathog ; 17(10): e1009881, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34624065

RESUMO

Pathogenic bacteria rely on protein phosphorylation to adapt quickly to stress, including that imposed by the host during infection. Penicillin-binding protein and serine/threonine-associated (PASTA) kinases are signal transduction systems that sense cell wall integrity and modulate multiple facets of bacterial physiology in response to cell envelope stress. The PASTA kinase in the cytosolic pathogen Listeria monocytogenes, PrkA, is required for cell wall stress responses, cytosolic survival, and virulence, yet its substrates and downstream signaling pathways remain incompletely defined. We combined orthogonal phosphoproteomic and genetic analyses in the presence of a ß-lactam antibiotic to define PrkA phosphotargets and pathways modulated by PrkA. These analyses synergistically highlighted ReoM, which was recently identified as a PrkA target that influences peptidoglycan (PG) synthesis, as an important phosphosubstrate during cell wall stress. We find that deletion of reoM restores cell wall stress sensitivities and cytosolic survival defects of a ΔprkA mutant to nearly wild-type levels. While a ΔprkA mutant is defective for PG synthesis during cell wall stress, a double ΔreoM ΔprkA mutant synthesizes PG at rates similar to wild type. In a mouse model of systemic listeriosis, deletion of reoM in a ΔprkA background almost fully restored virulence to wild-type levels. However, loss of reoM alone also resulted in attenuated virulence, suggesting ReoM is critical at some points during pathogenesis. Finally, we demonstrate that the PASTA kinase/ReoM cell wall stress response pathway is conserved in a related pathogen, methicillin-resistant Staphylococcus aureus. Taken together, our phosphoproteomic analysis provides a comprehensive overview of the PASTA kinase targets of an important model pathogen and suggests that a critical role of PrkA in vivo is modulating PG synthesis through regulation of ReoM to facilitate cytosolic survival and virulence.


Assuntos
Parede Celular/fisiologia , Listeria monocytogenes/metabolismo , Listeria monocytogenes/patogenicidade , Peptidoglicano/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Listeriose/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Virulência
13.
Lett Appl Microbiol ; 73(6): 684-693, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34607389

RESUMO

Propionibacterium acnes plays a major role in acne vulgaris. In the pre-experiment, the growth of P. acnes was inhibited effectively using surfactin; however, the antibacterial mechanism has not been described. Therefore, the aim of this study was to evaluate antibacterial activity and analyse the mechanism of surfactin against P. acnes. Minimum inhibitory concentration, time-killing kinetics and scanning electron microscopy were used to evaluate the activity of surfactin against P. acnes, which showed that 128 µg ml-1 effectively inhibited growth. Cell wall permeability was evaluated by detecting the extracellular alkaline phosphatase activity, which increased to 1·83- and 2·32-fold after incubating with 128 and 256 µg ml-1 of surfactin for 10 h, respectively. Propidium iodide fluorescence, leakage of nucleic acid, protein, K+ , and Ca2+ , membrane potential and the leakage of calcein from small unilamellar vesicles all increased after incubation with surfactin, indicating that its strong biological activities act mainly by altering membrane integrity. In a mouse model of acne, surfactin significantly reduced P. acnes-induced epidermal swelling and erythema. These results indicate that surfactin effectively inhibited the growth of P. acnes by destroying the cell wall and membrane, and is a potential candidate for acne treatment.


Assuntos
Acne Vulgar , Propionibacterium acnes , Acne Vulgar/tratamento farmacológico , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Parede Celular , Camundongos , Testes de Sensibilidade Microbiana
14.
Ecotoxicol Environ Saf ; 227: 112887, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34649137

RESUMO

Trivalent actinides such as Cm(III) are able to strongly interact with microbes and especially with bacterial cell walls. However, detailed knowledge of the influence of different cell wall components is somewhat lacking. For this investigation, we studied the formation of aqueous Cm(III) complexes with cell wall components (e.g., lipopolysaccharide, peptidoglycan, and plasma membranes) using time-resolved laser-induced fluorescence spectroscopy (TRLFS). For all systems, two specific Cm(III) complexes with the biomacromolecules were observed as a function of pH. Specifically, Cm(III) was found to bind to phosphate and carboxyl groups present in the structure of the biomacromolecules. Stability constants and luminescence parameters of the specific Cm(III) complexes were determined and are presented. The pH of the surrounding aqueous solution, the plasma membrane concentration, and proteins included in the crude plasma membrane fraction were found to significantly impact the complexation of Cm(III). The Cm(III) luminescence spectra with plasma membranes, cell wall polymers, as well as Gram-negative (Sporomusa sp. MT-2.99 and Pseudomonas fluorescens) and Gram-positive (Paenibacillus sp. MT-2.2) bacteria will be explained by linear combination fitting using the investigated components.


Assuntos
Cúrio , Európio , Parede Celular , Luminescência , Espectrometria de Fluorescência
15.
Molecules ; 26(19)2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34641284

RESUMO

To elucidate the chemical linkages between lignin and carbohydrates in ginkgo cell walls, 13C-2H-enriched cell wall-dehydrogenation polymers (CW-DHP) were selectively prepared with cambial tissue from Ginkgo biloba L. by feeding D-glucose-[6-2H2], coniferin-[α-13C], and phenylalanine ammonia-lyase (PAL) inhibitor. The abundant detection of 13C and 2H confirmed that D-glucose-[6-2H2] and coniferin-[α-13C] were involved in the normal metabolism of ginkgo cambial cells that had been effectively labelled with dual isotopes. In the ginkgo CW-DHP, ketal and ether linkages were formed between the C-α of lignin side chains and carbohydrates, as revealed by solid state CP/MAS 13C-NMR differential spectroscopy. Furthermore, the DMSO/TBAH ionic liquids system was used to fractionate the ball-milled CW-DHP into three lignin-carbohydrate complex (LCC) fractions: glucan-lignin complex (GL), glucomannan-lignin complex (GML), and xylan-lignin complex (XL). The XRD determination indicated that the cellulose type I of the GL was converted into cellulose type II during the separation process. The molecular weight was in the order of Ac-GL > Ac-GML > XL. The 13C-NMR and 1H-NMR differential spectroscopy of 13C-2H-enriched GL fraction indicated that lignin was linked with cellulose C-6 by benzyl ether linkages. It was also found that there were benzyl ether linkages between the lignin side chain C-α and glucomannan C-6 in the 13C-2H-enriched GML fraction. The formation of ketal linkages between the C-α of lignin and xylan was confirmed in the 13C-2H-enriched XL fraction.


Assuntos
Carboidratos/química , Ginkgo biloba/química , Lignina/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Parede Celular/química , Glucanos/química , Glucose/química , Estrutura Molecular , Espectroscopia de Prótons por Ressonância Magnética , Traqueófitas/química , Xilanos/química
16.
Biomacromolecules ; 22(11): 4669-4680, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34669375

RESUMO

Water is one of the principal constituents by mass of living plant cell walls. However, its role and interactions with secondary cell wall polysaccharides and the impact of dehydration and subsequent rehydration on the molecular architecture are still to be elucidated. This work combines multidimensional solid-state 13C magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) with molecular dynamics modeling to decipher the role of water in the molecular architecture of softwood secondary cell walls. The proximities between all main polymers, their molecular conformations, and interaction energies are compared in never-dried, oven-dried, and rehydrated states. Water is shown to play a critical role at the hemicellulose-cellulose interface. After significant molecular shrinkage caused by dehydration, the original molecular conformation is not fully recovered after rehydration. The changes include xylan becoming more closely and irreversibly associated with cellulose and some mannan becoming more mobile and changing conformation. These irreversible nanostructural changes provide a basis for explaining and improving the properties of wood-based materials.


Assuntos
Nanoestruturas , Água , Parede Celular , Celulose , Xilanos
17.
Ecotoxicol Environ Saf ; 227: 112906, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34673418

RESUMO

The mechanism of how potassium (K) attenuates cadmium (Cd)-induced demethylation and anabolism of cell wall (CW) pectin through the brassinolide (BR) signaling pathway was verified in Panax notoginseng (Burk.). The P. notoginseng pectin methylesterase gene (PnPME1) was cloned and functionally verified in tobacco. Pectin and BR metabolism, Cd content and the pectin methylation degree (PMD) were detected in response to K, 2,4-epibrassinolide (EBL), and brassinazole treatments of P. notoginseng and tobacco under Cd stress. Activity of the main root pectin methylesterase enzyme (PME) was promoted by 22.29% under the EBL treatment, and Cd content increased by 29.03% under Cd stress. Potassium reduced PME activity and Cd content in main root pectin by 61.03% and 50.73%, respectively, under the EBL and Cd co-treatment. Potassium inhibited the promoting effects of Cd stress on the expression of PnPME1 by 57.04%. Potassium also inhibited expression of BR synthesis genes PnDET2, PnROT3, PnCYP90A1, and PnBR6OX1 by 65.61%, 52.02%, 47.36%, and 55.16%, respectively, and reduced the accumulation of Cd. The PnPME1 was located in the CW. The activity of transgenic tobacco root PME was higher than that of the wild-type, while the PMD was significantly lower. The regulatory effects of K and EBL on tobacco root pectin metabolism were consistent with those in P. notoginseng. In conclusion, K downregulated the expression of BR synthesis genes in P. notoginseng roots under Cd stress and reduced the production of BRs, which inhibited PnPME1 expression. The reduction in PME activity increased the PMD, which reduced the accumulation of Cd.


Assuntos
Cádmio , Panax notoginseng , Brassinosteroides , Cádmio/toxicidade , Parede Celular , Pectinas , Raízes de Plantas , Potássio , Transdução de Sinais , Esteroides Heterocíclicos
18.
Plant Sci ; 312: 111060, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620427

RESUMO

Phosphate starvation (-Pi)-induced root hair is crucial for enhancing plants' Pi absorption. Proline-rich extensin-like receptor kinase 13 (PERK13) is transcriptionally induced by -Pi and co-expressed with genes associated with root hair growth. However, how PERK13 participates in -Pi-induced root hair growth remains unclear. Here, we found that PERK13 was transcriptionally responsive to Pi, nitrogen, and iron deficiencies. Loss of PERK13 function (perk13) enhanced root hair growth under Pi/nitrogen limitation. Similar phenotype was also observed in transgenic lines overexpressing PERK13 (PERK13ox). Under -Pi, both perk13 and PERK13ox showed prolonged root hair elongation and increased reactive oxygen species (ROS). Deletion analysis showed, in PERK13ox, the extracellular domain was indispensable for PERK13 in -Pi-induced root hair growth. Different transcription profiles were observed under -Pi between perk13 and PERK13ox with the jasmonate zim-domain genes being repressed in perk13 and genes involved in cell wall remodeling being increased in PERK13ox. Taken together, we demonstrated that PERK13 participates in -Pi-induced root hair growth probably via regulating root hair elongation and the generation of ROS. Our study also suggested PERK13 probably being a vital hub coupling the environmental cues and root hair growth, and might play dual roles in -Pi-induced root hair growth via different processes.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Arabidopsis/metabolismo , Fosfatos/deficiência , Raízes de Plantas/crescimento & desenvolvimento , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Parede Celular/genética , Parede Celular/metabolismo , Organogênese Vegetal/efeitos dos fármacos , Fenótipo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética
19.
Plant Sci ; 312: 111026, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620431

RESUMO

Brassinosteroids (BRs) play numerous important roles in plant growth and development. Previous studies reported that BRs could promote stem growth by regulating the expression of xyloglucan endotransglucosylase/hydrolases (XTHs). However, the mechanism of XTHs involved in stem growth remains unclear. In this study, PcBRU1, which belonged to the XTH family, was upregulated by exogenous BL treatment in Pyrus communis. The expression of PcBRU1 was highest in stems and lowest in leaves. Subcellular localization analysis indicated that PcBRU1 was located in the plasma membrane. Furthermore, overexpressing PcBRU1 in tobaccos promoted the plant height and internode length. Electron microscopy and anatomical structure analysis showed that the cell wall was significantly thinner and the cells were slenderer in transgenic tobacco lines overexpressing PcBRU1 than in wild-type tobaccos. PcBRU1 promoted stem growth as it loosened the cell wall, leading to the change in cell morphology. In addition, overexpressing PcBRU1 altered the root development and leaf shape of transgenic tobaccos. Taken together, the results could provide a theoretical basis for the XTH family in regulating cell-wall elongation and stem growth.


Assuntos
Crescimento Celular , Glicosiltransferases/metabolismo , Folhas de Planta/metabolismo , Caules de Planta/metabolismo , Pyrus/crescimento & desenvolvimento , Pyrus/genética , Pyrus/metabolismo , Parede Celular/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Glicosiltransferases/genética , Fenótipo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Caules de Planta/crescimento & desenvolvimento , Tabaco/genética , Tabaco/crescimento & desenvolvimento , Tabaco/metabolismo
20.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638975

RESUMO

Candida albicans is a commensal fungus of humans but can cause infections, particularly in immunocompromised individuals, ranging from superficial to life-threatening systemic infections. The cell wall is the outermost layer of C. albicans that interacts with the host environment. Moreover, antimicrobial peptides (AMPs) are important components in innate immunity and play crucial roles in host defense. Our previous studies showed that the human AMP LL-37 binds to the cell wall of C. albicans, alters the cell wall integrity (CWI) and affects cell adhesion of this pathogen. In this study, we aimed to further investigate the molecular mechanisms underlying the C. albicans response to LL-37. We found that LL-37 causes cell wall stress, activates unfolded protein response (UPR) signaling related to the endoplasmic reticulum (ER), induces ER-derived reactive oxygen species and affects protein secretion. Interestingly, the deletion of the SFP1 gene encoding a transcription factor reduced C. albicans susceptibility to LL-37, which is cell wall-associated. Moreover, in the presence of LL-37, deletion of SFP1 attenuated the UPR pathway, upregulated oxidative stress responsive (OSR) genes and affected bovine serum albumin (BSA) degradation by secreted proteases. Therefore, these findings suggested that Sfp1 positively regulates cell wall integrity and ER homeostasis upon treatment with LL-37 and shed light on pathogen-host interactions.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Candida albicans/metabolismo , Parede Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Proteínas Fúngicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Parede Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/genética , Proteínas Fúngicas/genética , Deleção de Genes , Homeostase/efeitos dos fármacos , Homeostase/genética , Interações Hospedeiro-Patógeno , Humanos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Resposta a Proteínas não Dobradas/genética , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
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