Cell Wall Thickness Research Articles

Synthesis of Indolyl Isothiocyanate and Its Inhibitory Activity against Fungi.

Based on previous research, this study synthesized 24 compounds by splicing the substructures of the indolyl group and the isothiocyanate group. Alternaria alternata, Phytophthora capsici, Botrytis cinerea, and Valsa mali were used to test the activity of the target compounds. At 100 μg/mL, compounds 8, 13, 14, and 17 exhibited excellent inhibitory effects of more than 80% on P. capsici, B. cinerea, and V. mail. The EC50 values of compounds 13 and 14 were 0.64 and 2.08 μg/mL, respectively. Potted antifungal activity demonstrated that compounds 13 and 14 had a protective effect of around 80% against B. cinerea at 200 μg/mL. Further physiological and biochemical studies on B. cinerea revealed that compound 13 thickened cell walls and caused mitochondrial vacuolization. Moreover, theoretical calculations indicated that the charge distribution of indolyl isothiocyanate compounds played a crucial role in the observed fungicidal activity. In summary, this study provided fundamental reference data for the derivative synthesis of these indolyl isothiocyanate compounds.

MsMIOX2, encoding a MsbZIP53-activated myo-inositol oxygenase, enhances saline-alkali stress tolerance by regulating cell wall pectin and hemicellulose biosynthesis in alfalfa.

Alfalfa is one of the most widely cultivated forage crops worldwide. However, soil salinization restricts alfalfa growth and development and affects global productivity. The plant cell wall is the first barrier against various stresses. Therefore, elucidating the alterations in cell wall architecture is crucial for stress adaptation. This study aimed to clarify the impact of myo-inositol oxygenase 2 (MsMIOX2) on cell wall pectin and hemicellulose biosynthesis under saline-alkali stress and identify the upstream transcription factors that govern MsMIOX2. MsMIOX2 activation induced cell wall pectin and hemicellulose accumulation under saline-alkali stress. The effects of MsMIOX2 in saline-alkali tolerance were investigated by characterizing its overexpression and RNA interference lines. MsMIOX2 overexpression positively regulated the antioxidant system and photosynthesis in alfalfa under saline-alkali stress. MsMIOX2 exhibited myo-inositol oxygenase activity, which increased polysaccharide contents, facilitated pectin and hemicellulose biosynthesis, and extended the cell wall thickness. However, MsMIOX2 RNA interference decreased cell wall thickness and alleviated alfalfa saline-alkali stress tolerance. In addition, MsbZIP53 was identified as an upstream transcriptional MsMIOX2 regulator by yeast one-hybrid, electrophoretic mobility shift assay, dual-luciferase, and beta-glucuronidase assays. MsbZIP53 overexpression increased MsMIOX2 expression, elevated MIOX activity, reinforced the antioxidant system and photosynthesis, and increased saline-alkali stress tolerance in alfalfa. In conclusion, this study presents a novel perspective for elucidating the molecular mechanisms of saline-alkali stress tolerance in alfalfa and emphasizes the potential use of MsMIOX2 in alfalfa breeding.

Enhancement of intracellular extraction from Oscillatoria okine and the potential use of the extract as a supplement to fetal bovine serum in animal cell culture

A robust cell wall and well-organized thylakoid cyanobacteria can be candidates as a promising resource for C-phycocyanin (C-PC) and intracellular applications in various biotechnological areas. However, the development of extraction techniques with minimal chemical contamination to obtain the components remains an ongoing challenge. This study aimed to assess the efficacy of C-PC and intracellular extraction from Ocillatoria okeni TISTR8549 utilizing freezing-thaw (FT), pulsed electric field (PEF), and high-pressure homogenization (HPH) techniques. Additionally, the potential of O. okeni extract as a supplement and substitute for fetal bovine serum (FBS) in HaCaT cell culture was investigated. FT appeared to be the most proper method for C-PC extraction, yielding the highest purity and yield, although requiring 18 cycles for product accomplishment. PEF seemed unsuitable for intracellular component extraction from cyanobacteria with thick cell walls. The need for increased pulses resulted in thermal elevation and prolonged incubation times led to protein degradation. HPH proves to be an effective method for intracellular extraction, yielding high protein content suitable for the potential substitution of FBS in mammalian cell culture. Particularly, increasing pressure during HPH extraction leads to a decrease in protein yield. Resazurin and SRB assays revealed that adding algal extract in culture medium at concentrations of 1 % (w/v) improved HaCaT cell viability without disrupting cell morphology and metabolic processes. However, substituting algal extract in FBS resulted in cell proliferation decrease. Therefore, supplementing O. okeni extract during cell culture improved HaCaT cell proliferation, but it was unsuitable substitute for FBS in the culture medium. However, the feasibility of employing algal extracts as FBS replacements in cell culture is interesting and warrants further detailed investigation into the specific intracellular components that could serve as substitutes for FBS. Such an approach could offer an alternative source, mitigating ethical concerns and reducing costs associated with FBS usage.

Research on a Honeycomb Structure for Pyroshock Isolation at the Spacecraft–Rocket Interface

Honeycomb is a splendid kind of structure for aerospace engineering with the advantages of light weight, good shock absorption, and good structural stability. This article aims to provide methods to isolate Pyroshocks based on a honeycomb structure and guarantee the safety of such equipment against a high-frequency shock response. According to stress wave theory, an equation for stress wave transmittance of the honeycomb structure is derived considering the effect of cell wall length and thickness, where desirable honeycomb parameters are obtained. The complexity of the transfer path of the honeycomb structure is exploited to build the spacecraft–rocket interface, which could increase the impedance of the stress wave dramatically. Both finite element analysis and experiments are carried out to validate the shock isolation strategies. The influence of parameters, such as cell wall length and the thickness of the stainless-steel honeycomb, on the isolation performance is analyzed. It is revealed that the honeycomb structure has a significant effect on Pyroshock isolation performance when the wall length of the honeycomb cell is 8 mm and the thickness of the cell is 0.1 mm.

Herbicidal Sorbicillinoid Analogs Cause Lignin Accumulation in Aspergillus aculeatus TE-65L.

Five new sorbicillinoid derivatives, including (±)-aspersorbicillin A [(±)-1], a pair of enantiomers at C-9, and aspersorbicillins B-D (2-4), together with two known analogs (5 and 6) were isolated from the endophytic fungus Aspergillus aculeatus TE-65L. Their structures including absolute configurations were determined by detailed spectroscopic analyses and electronic circular dichroism calculations. The herbicidal activity of sorbicillinoids on the germ and radicle elongation of various weed types was reported for the first time. Compound 1 displayed significant herbicidal activity against Eleusine indica germ elongation (IC50 = 28.8 μg/mL), while compound 6 inhibited radicle elongation (IC50 = 25.6 μg/mL). Both were stronger than those of glyphosate (66.2 and 30.9 μg/mL, respectively). Further transcriptomic and LC-MS/MS metabolomic analysis indicated that 6 induced the transcriptional expressions of genes related to the lignin biosynthetic pathway, resulting in lignin accumulation. Transmission electron microscopy confirmed the cell wall thickening of seeds treated with 6, suggesting weed growth inhibition. This study reveals new lead compounds for fabricating natural herbicides and expands the agricultural use of sorbicillinoid analogs.

The transcription factor ZmbHLH105 confers cadmium tolerance by promoting abscisic acid biosynthesis in maize

Cadmium (Cd), a highly toxic heavy metal, profoundly impacts crop productivity. The bHLH-type transcription factors regulate plant stress responses, yet their involvement in maize's Cd stress response remains unclear. Here, we studied ZmbHLH105, a maize bHLH gene induced by Cd exposure. Overexpression of ZmbHLH105 in maize seedlings, which were treated with 1.0 mM CdCl2 for 7 days, increased endogenous ABA levels, decreased Cd accumulation, and enhanced Cd stress tolerance. ZmbHLH105 directly bound to promoter regions of two key ABA biosynthesis genes ZmNCED1/2, activating their transcription, thus boosting ABA levels and Cd tolerance. ZmbHLH105-overexpression promoted lignin synthesis, while ZmbHLH105-RNAi attenuated this effect. Exogenous ABA supplementation increased lignin content in Cd-stressed maize roots, suggesting ZmbHLH105-mediated Cd tolerance involves ABA-induced lignin deposition and cell wall thickening. Moreover, Cd transport-related gene expression was suppressed in ZmbHLH105 overexpression lines. Our findings demonstrate that ZmbHLH105 decreases Cd accumulation, improving Cd tolerance by enhancing ABA biosynthesis, increasing lignin deposition, thickening cell walls, and inhibiting Cd absorption in maize roots. This study unveils ZmbHLH105's mechanisms in Cd tolerance, highlighting its potential in breeding low Cd-accumulating crops for food and environment safety.

Mutation of tomato xyloglucan transglucosylase/hydrolase5 increases fruit firmness and contributes to prolonged shelf life

Fruit ripening in tomato is a highly coordinated developmental process accompanied with fruit softening, which is closely associated with cell wall degradation and remodeling. Xyloglucan endotransglucosylase/hydrolases (XTHs) are known to play an essential role in cell wall xyloglucan metabolism. Tomato XTH5 exhibits xyloglucan endotransglucosylase (XET) activity in vitro, but the understanding of its biological role in fruit ripening remains unclear. In this study, we revealed that SlXTH5 is highly expressed in mature fruits. Knockout mutant plants of SlXTH5 were generated by CRISPR/Cas9 gene editing strategy in tomato cultivar Micro-Tom. The mutant fruits showed accelerated transition from unripe to ripe process and earlier ethylene accumulation compared to wild type fruits. Although the mutation of SlXTH5 did not affect the size, weight and number of fruits, it indeed increased fruit firmness and extended shelf life, which is probably attributed to the increased cell layer and cell wall thickness of pericarp tissue. Pathogen infection experiment showed the enhanced resistance of mutant fruits to Botrytis cinerea. These results revealed the role of SlXTH5 in fruit ripening process, and provide new insight into how cell wall metabolism and remodeling regulate fruit softening and shelf life.

Enhanced visualization of nuclear staining and cell cycle analysis for the human commensal Malassezia

Malassezia is a lipophilic commensal yeast that resides mainly on the mammalian skin and is also found to associate with the internal organs. Dysbiosis of Malassezia is related to several diseases and often escapes detection as it is difficult to culture and maintain. Malassezia cell wall differs from other budding yeasts like S. cerevisiae due to the difference in the lipid content and is difficult to transform. In this study, we present a methodology to stain Malassezia's nucleus and perform cell cycle studies. However, staining presents a challenge due to its exceptionally thick cell wall with high lipid content, hindering conventional methods. Our novel methodology addresses this challenge and enables the staining of the Malassezia nucleus with a low background. This would allow researchers to visualize the overall nuclear health specifically nuclear morphology and analyze DNA content, crucial for cell cycle progression. By employing DNA-specific dyes like DAPI or Hoechst, we can observe the nuclear structure, and using PI we can differentiate cells in distinct cell cycle phases using techniques like flow cytometry. This novel staining methodology unlocks the door for in-depth cell cycle analysis in Malassezia which has challenged us through ages being refractory to genetic manipulations, paving the way for a deeper understanding of this commensal fungus and its potential role in human health.

Integrated insights into the cytological, histochemical, and cell wall composition features of Espinosa nothofagi (Hymenoptera) gall tissues: implications for functionality.

Many insect-induced galls are considered complex structures due to their tissue compartmentalization and multiple roles performed by them. The current study investigates the complex interaction between Nothofagus obliqua host plant and the hymenopteran gall-inducer Espinosa nothofagi, focusing on cell wall properties and cytological features. The E. nothofagi galls present an inner cortex with nutritive and storage tissues, as well as outer cortex with epidermis, chlorenchyma, and water-storing parenchyma. The water-storing parenchyma cells are rich in pectins, heteromannans, and xyloglucans in their walls, and have large vacuoles. Homogalacturonans contribute to water retention, and periplasmic spaces function as additional water reservoirs. Nutritive storage cell walls support nutrient storage, with plasmodesmata facilitating nutrient mobilization crucial for larval nutrition. Their primary and sometimes thick secondary cell walls support structural integrity and act as a carbon reserve. The absent labeling of non-cellulosic epitopes indicates a predominantly cellulosic nature in nutritive cell walls, facilitating larval access to lipid, protein, and reducing sugar-rich contents. The nutritive tissue, with functional chloroplasts and high metabolism-related organelles, displays signs of self-sufficiency, emphasizing its role in larval nutrition and cellular maintenance. Overall, the intricate cell wall composition in E. nothofagi galls showcases adaptations for water storage, nutrient mobilization, and larval nutrition, contributing significantly to our understanding of plant-insect interactions.

Baseline sensitivity and physiological characteristics of natural product hinokitiol against Sclerotinia sclerotiorum.

Sclerotinia sclerotiorum, a pathogenic fungus of oilseed rape, poses a severe threat to the oilseed rapeseed industry. In this study, we evaluated the potential of the natural compound hinokitiol against S. sclerotiorum by determining its biological activity and physiological characteristics. Our results showed that hinokitiol strongly inhibited the hyphae expansion of S. sclerotiorum, and its effective concentration of hyphae growing inhibition by 50% (EC50) against 103 S. sclerotiorum strains varied from 0.36 to 3.45 μg/mL, with an average of 1.23 μg/mL. Hinokitiol possessed better protective efficacy than therapeutic effects, and it exhibited no cross-resistance between carbendazim. After treatment with hinokitiol, many vesicular protrusions developed on the mycelium with rough surface and thickened cell wall. Moreover, the cell membrane permeability and glycerol content increased, while the oxalic acid declined after hinokitiol treatment. In addition, hinokitiol induced membrane lipid peroxidation and improved the production of reactive oxygen species (ROS) in S. sclerotiorum. Importantly, real-time quantitative polymerase chain reaction showed that cell wall and ROS synthesis-related genes were significantly up-regulated after hinokitiol treatment. This study revealed that hinokitiol has good biological activity against S. sclerotiorum and could be considered as an alternative bio-fungicide for the resistance management in controlling sclerotinia stem rot infected by S. sclerotiorum. These investigations provided new insights into understanding the toxic action of hinokitiol against pathogenic fungi. © 2024 Society of Chemical Industry.

Arabinosylation of cell wall extensin is required for the directional response to salinity in roots.

Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.

The roles of cell wall polysaccharides in response to waterlogging stress in Brassica napus L. root

BackgroundBrassica napus L. (B. napus) is susceptible to waterlogging stress during different cultivation periods. Therefore, it is crucial to enhance the resistance to waterlogging stress to achieve a high and stable yield of B. napus.ResultsHere we observed significant differences in the responses of two B. napus varieties in root under waterlogging stress. The sensitive variety (23651) exhibited a more pronounced and rapid reduction in cell wall thickness and root integrity compared with the tolerant variety (Santana) under waterlogging stress. By module clustering analysis based on transcriptome data, we identified that cell wall polysaccharide metabolism responded to waterlogging stress in root. It was found that pectin content was significantly reduced in the sensitive variety compared with the tolerant variety. Furthermore, transcriptome analysis revealed that the expression of two homologous genes encoding polygalacturonase-inhibiting protein 2 (PGIP2), involved in polysaccharide metabolic pathways, was highly upregulated in root of the tolerant variety under waterlogging stress. BnaPGIP2s probably confer waterlogging resistance by inhibiting the activity of polygalacturonases (PGs), which in turn reduces the degradation of the pectin backbone polygalacturonic acid.ConclusionsOur findings demonstrate that cell wall polysaccharides in root plays a vital role in response to the waterlogging stress and provide a theoretical foundation for breeding waterlogging resistance in B. napus varieties.

Analysis of R2R3-MYB Repressor Subfamily Identifies FcMYB57 as a Negative Regulator of Anthocyanin Biosynthesis in Ficus carica L. Fruit

Dry fig is a traditional healthy snack and has important economic value in a number of Mediterranean and Middle Eastern countries. Cultivars with no anthocyanin accumulation in the fruit peel are preferred for dry fig production. R2R3-MYB transcription factors have promotive or repressive regulatory roles in plant anthocyanin biosynthesis. In this study, 113 R2R3-MYB genes were identified in Ficus carica, 3 of which were assigned to the S4 subfamily of flavonoid-biosynthesis repressors. FcMYB57 was further recruited as a candidate anthocyanin-biosynthesis repressor based on its sequence features and expression, which was significantly negatively correlated with that of anthocyanin-biosynthesis structural genes. Transient overexpression of FcMYB57 in strawberry totally inhibited fruit pigmentation and significantly increased fruit firmness. The metabolomic analysis confirmed a significant reduction in the contents of cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside, as well as other flavonoids, and transmission electron microscopy revealed an increment in cell-wall thickness. Transcriptome analysis showed downregulation of anthocyanin-biosynthesis structural genes and upregulation of genes related to xylan synthesis. Yeast one-hybrid and dual luciferase assays demonstrated a negative regulatory effect of FcMYB57 on the promoter of FcUFGT3 (UDP glucose-flavonoid 3-O-glcosyl-transferase). Yeast two-hybrid assay showed that FcMYB57 does not interact with FcbHLH42, 3, 14, MYC2, or FcTTG1, all of which have a previously identified or predicted role in flavonoid biosynthesis, however, interaction was detected with FcTPL (Topless), suggesting that FcMYB57 serves as an active repressor of anthocyanin biosynthesis. This is the first identification of an anthocyanin-biosynthesis repressor in fig, with a possible role in fig fruit quality.

Regulatory networks of senescence-associated gene-transcription factors promote degradation in Moso bamboo shoots.

Bamboo cultivation, particularly Moso bamboo (Phyllostachys edulis), holds significant economic importance in various regions worldwide. Bamboo shoot degradation (BSD) severely affects productivity and economic viability. However, despite its agricultural consequences, the molecular mechanisms underlying BSD remain unclear. Consequently, we explored the dynamic changes of BSD through anatomy, physiology and the transcriptome. Our findings reveal ruptured protoxylem cells, reduced cell wall thickness and the accumulation of sucrose and reactive oxygen species (ROS) during BSD. Transcriptomic analysis underscored the importance of genes related to plant hormone signal transduction, sugar metabolism and ROS homoeostasis in this process. Furthermore, BSD appears to be driven by the coexpression regulatory network of senescence-associated gene transcription factors (SAG-TFs), specifically PeSAG39, PeWRKY22 and PeWRKY75, primarily located in the protoxylem of vascular bundles. Yeast one-hybrid and dual-luciferase assays demonstrated that PeWRKY22 and PeWRKY75 activate PeSAG39 expression by binding to its promoter. This study advanced our understanding of the molecular regulatory mechanisms governing BSD, offering a valuable reference for enhancing Moso bamboo forest productivity.

LC-MS/MS phenolic profileand remedial role ofUrtica dioica extract against Li2CO3-induced toxicity.

In this study, the protective role of Urtica dioica extract (Udex) against Li2CO3 toxicity in Allium cepa L. was investigated using various parameters such as germination rates, root growth, weight gain, mitotic index (MI), malondialdehyde (MDA), micronucleus (MN), antioxidant enzyme activity, chromosomal abnormalities (CAs) and anatomical changes. As the biological activity of Udex is related to its active content, the profile of phenolic compounds was determined by LC-MS/MS analysis. Li2CO3 caused abnormalities in the tested parameters and serious regressions in germination parameters. Application of 100mg/L Li2CO3 reduced the chlorophyll a and b contents by 73.04% and 65.7%, respectively. Li2CO3 application exhibited a cytotoxic effect by inducing significant decreases in MI and increases in the frequency of MN, and also showed a genotoxic effect by causing CAs. After 100mg/L Li2CO3 treatment, MDA, proline, superoxide dismutase, and catalase levels increased by 54.9%, 58.5%, 47.8%, and 52.3%, respectively. Li2CO3 and Udex co-administration resulted in a regression in increased biochemical parameters and genotoxicity parameters, and an improvement in germination parameters. Furthermore, Udex demonstrated efficacy in mitigating the detrimental effects of Li2CO3 on the root tip, particularly in the 200µg/mL Udex-treated group. The thickening of the cortex cell wall and conduction tissue, which is commonly induced by Li₂CO₃, was not observed in the Udex-treated group. The protective effect of Udex can be explained by the phenolic compounds it contains. Rutin was detected as the major component in Udex and other phenolics were listed according to their presence rate as protecatechuic acid > caffeic acid > p-coumaric acid > syringic acid > rosemarinic acid > epicatechin. Li ions, which increase in the environment after industrialization, are an important environmental pollutant and exhibit toxicity that affects many pathways in organisms. Scientific research should not only detect these toxic effects but also develop solutions to such problems. In this study, it was determined that the Udex application had a toxicity-reducing role against Li2CO3 toxicity. Also, it has been demonstrated that A. cepa is an important indicator in determining this toxicity and toxicity-reducing applications.

Investigation of the protective role of Ginkgo biloba L. against phytotoxicity, genotoxicity and oxidative damage induced by Trifloxystrobin

Trifloxystrobin (TFS) is a widely used strobilurin class fungicide. Ginkgo biloba L. has gained popularity due to its recognized medicinal and antioxidant properties. The aim of this study was to determine whether Ginkgo biloba L. extract (Gbex) has a protective role against TFS-induced phytotoxicity, genotoxicity and oxidative damage in A. cepa. Different groups were formed from Allium cepa L. bulbs subjected to tap water (control), 200 mg/L Gbex (Gbex1), 400 mg/L Gbex (Gbex2), 0.8 g/L TFS solution (TFS), 200 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex1) and 400 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex2), respectively. The phenolic composition of Gbex and alterations in the morphological, physiological, biochemical, genotoxicity and anatomical parameters were evaluated. Rutin, protocatechuic acid, catechin, gallic acid, taxifolin, p-coumaric acid, caffeic acid, epicatechin, syringic acid and quercetin were the most prevalent phenolic substances in Gbex. Rooting percentage, root elongation, weight gain, chlorophyll a and chlorophyll b decreased by approximately 50%, 85%, 77%, 55% and 70%, respectively, as a result of TFS treatment compared to the control. In the TFS group, the mitotic index fell by 28% compared to the control group, but chromosomal abnormalities, micronuclei frequency and tail DNA percentage increased. Fragment, vagrant chromosome, sticky chromosome, uneven chromatin distribution, bridge, vacuole-containing nucleus, reverse polarization and irregular mitosis were the chromosomal abnormalities observed in the TFS group. The levels of proline (2.17-fold) and malondialdehyde (2.71-fold), as well as the activities of catalase (2.75-fold) and superoxide dismutase (2.03-fold) were increased by TFS in comparison to the control. TFS-provoked meristematic disorders were damaged epidermis and cortex cells, flattened cell nucleus and thickened cortex cell wall. Gbex combined with TFS relieved all these TFS-induced stress signs in a dose-dependent manner. This investigation showed that Gbex can play protective role in A. cepa against the phytotoxicity, genotoxicity and oxidative damage caused by TFS. The results demonstrated that Gbex had this antioxidant and antigenotoxic potential owing to its high phenolic content.

Mechanical properties of a novel negative Poisson's ratio gradient structure

A novel cellular structure is proposed based on bionic structure with negative Poisson's ratio characteristic, and the cell is periodically expanded in the in-plane direction to create a new honeycomb structure. The influence of gradient changes of the structural parameters on the load-bearing capacity and damping characteristics of the structure is investigated through a combination method of finite element numerical simulations and experiments. The results indicate that the concentric gradient arrangement of cell wall thickness and angle parameters, and the symmetrical gradient arrangement of cell height, wall thickness and angle parameters have the most significant influence on the static bearing capacity of the structure. In contrast, the gradient arrangement under the corner circle diameter has minimal effect on the static bearing capacity of the structure. Under the same conditions, the peak values of the transmissibility of C2 (large angle at constraint end and loading end, and smaller angle in the middle) and C3 structures (angle gradually increases from the loading end to the constraint end) are significantly reduced between the frequency 2 Hz and 1024 Hz. The peak values of the transmissibility of the structures C2 and C3 are respectively decreased by 20% and 25% compared to that of the non-gradient structure. This shows that the vibration damping effect of these two structures is better. The structure with the gradient change and the structure without the gradient change of the new honeycomb structure can both achieve certain vibration reduction and isolation from the middle to high frequency range.

Staphylococcus aureus Stress Response to Bicarbonate Depletion.

Bicarbonate and CO2 are essential substrates for carboxylation reactions in bacterial central metabolism. In Staphylococcus aureus, the bicarbonate transporter, MpsABC (membrane potential-generating system) is the only carbon concentrating system. An mpsABC deletion mutant can hardly grow in ambient air. In this study, we investigated the changes that occur in S. aureus when it suffers from CO2/bicarbonate deficiency. Electron microscopy revealed that ΔmpsABC has a twofold thicker cell wall thickness compared to the parent strain. The mutant was also substantially inert to cell lysis induced by lysostaphin and the non-ionic surfactant Triton X-100. Mass spectrometry analysis of muropeptides revealed the incorporation of alanine into the pentaglycine interpeptide bridge, which explains the mutant's lysostaphin resistance. Flow cytometry analysis of wall teichoic acid (WTA) glycosylation patterns revealed a significantly lower α-glycosylated and higher ß-glycosylated WTA, explaining the mutant's increased resistance towards Triton X-100. Comparative transcriptome analysis showed altered gene expression profiles. Autolysin-encoding genes such as sceD, a lytic transglycosylase encoding gene, were upregulated, like in vancomycin-intermediate S. aureus mutants (VISA). Genes related to cell wall-anchored proteins, secreted proteins, transporters, and toxins were downregulated. Overall, we demonstrate that bicarbonate deficiency is a stress response that causes changes in cell wall composition and global gene expression resulting in increased resilience to cell wall lytic enzymes and detergents.

Effects of foliar treatments with urea and nano-urea on the cell walls of Monastrell grape skins

Cell wall composition can be affected by nitrogen availability in the vineyard. Foliar application of urea is effective in supplying nitrogen needs and increasing the nitrogen content of musts. Due to the low recoveries of urea fertilisation, more effective application methods such as the use of nanotechnology are needed. In this work, the effect on the composition of Monastrell grape skin cell walls, after foliar application of urea and amorphous calcium phosphate nano-particles doped with urea was studied. The treatments with urea and nano-urea, although the urea content in the nano-treatment was eight times lower than in the conventional treatment, produce an equivalent modification of the cell wall. In fact, both treatments produced an increase in cell wall thickness and in cell wall composition, contents of proteins, hemicellulose and uronic acids also increased. However, phenolic compounds were not affected and cellulose showed lower concentrations than control grapes. Regarding the spectrophotometric parameters of the wine studied, the anthocyanins content and colour intensity were reduced in wines with both treatments and the total polyphenol index was slightly affected.

Nonlinear models based on leaf architecture traits explain the variability of mesophyll conductance across plant species.

Mesophyll conductance ( ) describes the efficiency with which moves from substomatal cavities to chloroplasts. Despite the stipulated importance of leaf architecture in affecting , there remains a considerable ambiguity about how and whether leaf anatomy influences . Here, we employed nonlinear machine-learning models to assess the relationship between 10 leaf architecture traits and . These models used leaf architecture traits as predictors and achieved excellent predictability of . Dissection of the importance of leaf architecture traits in the models indicated that cell wall thickness and chloroplast area exposed to internal airspace have a large impact on interspecific variation in . Additionally, other leaf architecture traits, such asleaf thickness, leaf densityand chloroplast thickness, emerged as important predictors of . We also found significant differences in the predictability between models trained on different plant functional types. Therefore, by moving beyond simple linear and exponential models, our analyses demonstrated that a larger suite of leaf architecture traits drive differences in than has been previously acknowledged. These findings pave the way for modulating by strategies that modify its leaf architecture determinants.