Diabetic foot ulcers are one of the most severe complications of diabetes that have imposed great financial and psychological burdens on diabetic patients.A Nocardia rubra cell wall skeleton(Nr-CWS)can be externally a...Diabetic foot ulcers are one of the most severe complications of diabetes that have imposed great financial and psychological burdens on diabetic patients.A Nocardia rubra cell wall skeleton(Nr-CWS)can be externally applied to accelerate wound healing.However,its clinical application has not yet been reported.Herein,we report two patients with diabetic foot ulcers treated with Nr-CWS.After wound debridement,the wound was covered with a sterile cotton ball infiltrated with an Nr-CWS that was diluted with 2.0 mL of saline.The covers were changed every two days until complete wound healing occurred.The two wounds healed after 3 and 12 weeks,respectively.This article aims to provide a new treatment for diabetic foot ulcers,with the hope that physicians may consider an Nr-CWS as a complementary method for the treatment of chronic wounds.展开更多
Objective:To observe and compare the curative effect between the intrapleural-chemotherapy combined Nocardia rubra cell wall skeleton-injection and the Nocardia rubra cell wall skeleton-injection after control of the ...Objective:To observe and compare the curative effect between the intrapleural-chemotherapy combined Nocardia rubra cell wall skeleton-injection and the Nocardia rubra cell wall skeleton-injection after control of the malignant pleural effusion by chemotherapy.Methods:Every time after elimination of pleural effusion,we injected DDP and Nocardia rubra cell wall skeleton at the same time into pleural cavity;or after we emplaced an improved central vena catheter into pleural cavity then took out closed-drainage or eliminated the pleural effusion every day,then injected 5-FU 0.5 qd intrapleural-space.After the malignant pleural effusion had being controlled,800μg Nocardia rubra cell wall skeleton was injected intrapleural-space. (We call it as"improved following-therapy").Results:Using the improved following-therapy,the control rate of malignant pleural effusion increased:CR+PR,79.07%>65.79%(P<0.05),and the incidence rate of the encapsulated pleural effusion that would impact on patient’s respiratory faction decreased.Conclusion:Giving chemotherapy after closed-drainage or immediately after taking out pleural effusion everyday,then giving biotherapy after pleural effusion had been controlled,the curative effect would be enhanced and the side-reaction would be reduced.展开更多
Natural foods,such as whole pulses,are recommended in the dietary guidelines of the US and China.The plant cell wall structure in whole pulses has important implications for the nutritional functionalities of starch.I...Natural foods,such as whole pulses,are recommended in the dietary guidelines of the US and China.The plant cell wall structure in whole pulses has important implications for the nutritional functionalities of starch.In this study,garbanzo bean cells with varying degrees of cell wall integrity were subjected to dry heat treatment(DHT)and used to elucidate the food structure-starch digestion properties of pulse food.The morphological features suggested that all cell samples do not exhibit remarkable changes after being subjected to DHT.Molecular rearrangement and the crystallite disruption of starch granules entrapped in cells occurred during DHT as assessed by the crystal structure and thermal properties.DHT decreased the inhibitory effects of enzymes of both the soluble and insoluble components,but the digestion rate and extent of slightly and highly damaged cell samples did not exhibit significant differences compared with their native counterparts.We concluded that the starch digestion of pulse cotyledon cells is primarily determined by the intactness of the cellular structure.This study reveals the role of food structure on the ability to retain the desirable nutritional properties of starch after subjection to physical modification.展开更多
Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a n...Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a novel brittle culm 25(bc25)mutant with reduced growth and partial sterility.BC25 encodes an UDP-glucuronic acid decarboxylase involved in cellulose synthesis and belongs to the UXS family.A single-nucleotide mutation in BC25 accounts for its altered cell morphology and cellwall composition.Transmission electron microscopy analysis showed that the thickness of the secondary cell wall was reduced in bc25.Monosaccharide analysis revealed significant increases in content of rhamnose and arabinose but not of other monosaccharides,indicating that BC25 was involved in xylose synthesis with some level of functional redundancy.Enzymatic assays suggested that BC25 functions with high activity to interconvert UDP-glucuronic acid(UDP-Glc A)and UDP-xylose.GUS staining showed that BC25 was ubiquitously expressed with higher expression in culm,root and sheath,in agreement with that shown by quantitative real-time(q RT)-PCR.RNA-seq further suggested that BC25 is involved in sugar metabolism.We conclude that BC25 strongly influences rice cell wall formation.展开更多
Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is ...Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is known about molecular mechanisms underlying anther cell elongation.Here,we found that properly activated cell elongation regulators at transcriptional levels in loss-of-function ZmMs33 mutant(ms33-6038)anthers failed to promote maize anther elongation.ZmMs33 deficiency disrupted metabolic homeostasis mainly by inhibiting both photosynthesis in anther endothecium and lipid accumulation in anther tapetum.Importantly,ms33-6038 anthers displayed ectopic,premature and excessive secondary cell wall thickening in anther middle layer,which constrained cell elongation structurally and blocked nutrient flows across different anther wall layers.The metabolic disorder was only found in ms33-6038 mutant rather than several representative male-sterility lines at transcriptional and post-translational levels.Collectively,the disordered metabolisms and blocked nutrient flows defeated the activated cell elongation regulators,and finally inhibited anther elongation and growth with a unique‘‘idling effect”in ms33-6038 mutant.展开更多
Phosphorus(P) starvation in rice facilitates the reutilization of root cell wall P by enhancing the pectin content. NaCl modulates pectin content, however, it is still unknown whether NaCl is also involved in the proc...Phosphorus(P) starvation in rice facilitates the reutilization of root cell wall P by enhancing the pectin content. NaCl modulates pectin content, however, it is still unknown whether NaCl is also involved in the process of pectin regulated cell wall P remobilization in rice under P starved conditions. In this study, we found that 10 mmol/L NaCl increased the shoot and root biomasses under P deficiency to a remarkable extent, in company with the elevated shoot and root soluble P contents in rice. Further analysis indicated that exogenous NaCl enhanced the root cell wall P mobilization by increasing the pectin methylesterase activity and uronic acid content in pectin suggesting the involvement of NaCl in the process of cell wall P reutilization in P starved rice roots. Additionally, exogenous NaCl up-regulated the expression of P transporter OsPT6, which was induced by P deficiency, suggesting that NaCl also facilitated the P translocation prominently from root to shoot in P starved rice. Moreover, exogenous abscisic acid(ABA) can reverse the NaCl-mediated mitigation under P deficiency, indicating the involvement of ABA in the NaCl regulated root cell wall P reutilization. Taken together, our results demonstrated that NaCl can activate the reutilization of root cell wall P in P starved rice, which is dependent on the ABA accumulation pathway.展开更多
Fruit development and ripening is a complex procedure(Malus×domestica Borkh.)and can be caused by various factors such as cell structure,cell wall components,and cell wall hydrolytic enzymes.In our study,we focus...Fruit development and ripening is a complex procedure(Malus×domestica Borkh.)and can be caused by various factors such as cell structure,cell wall components,and cell wall hydrolytic enzymes.In our study,we focused on the variations in fruit firmness,cell wall morphology and components,the activity of cell wall hydrolytic enzymes and the expression patterns of associated genes during fruit development in two different types of apple cultivars,the hard-crisp cultivar and the loose-crisp cultivar.In this paper,the aim was to find out the causes of the texture variations between the different type cultivars.Cell wall materials(CWMs),hemicellulose and cellulose content were strongly associated with variations in fruit firmness during the fruit development.The content of water soluble pectin(WSP)and chelator soluble pectin(CSP)gradually increased,while the content of ionic soluble pectin(ISP)showed inconsistent trends in the four cultivars.The activities of polygalacturonase(PG),β-galactosidase(β-gal),cellulase(CEL),and pectate lyase(PL)gradually increased in four cultivars.And the activities of PG,β-gal,and CEL were higher in‘Fuji’and‘Honeycrisp’fruit with the fruit development,while the activity of PL of‘Fuji’and‘Honeycrisp’was lower than that of‘ENVY’and‘Modi’.Both four cultivars of fruit cells progressively became bigger as the fruit expanded,with looser cell arrangements and larger cell gaps.According to the qRT-PCR,the relative expression levels of MdACO and Mdβ-gal were notably enhanced.Our study showed that there were large differences in the content of ISP and hemicellulose,the activity of PL and the relative expression of Mdβ-gal between two different types of apple cultivars,and these differences might be responsible for the variations in the texture of the four cultivars.展开更多
The morphological development of rice(Oryza sativa L.)leaves is closely related to plant architecture,physiological activities,and resistance.However,it is unclear whether there is a co-regulatory relationship between...The morphological development of rice(Oryza sativa L.)leaves is closely related to plant architecture,physiological activities,and resistance.However,it is unclear whether there is a co-regulatory relationship between the morphological development of leaves and adaptation to drought environment.In this study,a drought-sensitive,roll-enhanced,and narrow-leaf mutant(renl1)was induced from a semi-rolled leaf mutant(srl1)by ethyl methane sulfonate(EMS),which was obtained from Nipponbare(NPB)through EMS.Map-based cloning and functional validation showed that RENL1 encodes a cellulose synthase,allelic to NRL1/OsCLSD4.The RENL1 mutation resulted in reduced vascular bundles,vesicular cells,cellulose,and hemicellulose contents in cell walls,diminishing the water-holding capacity of leaves.In addition,the root system of the renl1 mutant was poorly developed and its ability to scavenge reactive oxygen species(ROS)was decreased,leading to an increase in ROS after drought stress.Meanwhile,genetic results showed that RENL1 and SRL1 synergistically regulated cell wall components.Our results revealed a theoretical basis for further elucidating the molecular regulation mechanism of cellulose on rice drought tolerance,and provided a new genetic resource for enhancing the synergistic regulation network of plant type and stress resistance,thereby realizing simultaneous improvement of multiple traits in rice.展开更多
The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies h...The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies have focused on high-oil cultivars with high grain and straw quality.Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality.In the present study,a high-oil inbred line(By804)was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines(RILs).The phenotypes of six cell-wall-related traits were recorded,and QTL analysis was performed with a genetic map constructed with SNP markers.All traits were significantly correlated with one another and showed high broad-sense heritability.Of 20 QTLs mapped,the QTL associated with each trait explained 10.0%–41.1%of phenotypic variation.Approximately half of the QTL each explained over 10%of the phenotypic variation.These results provide a theoretical basis for improving maize forage quality by marker-assisted selection.展开更多
Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting th...Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting the structure and strength of the cell wall.To explore cell wall development during secondary cell wall lignification in maize stalks,conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci(QTLs)of the cell wall components and digestibility traits during five growth stages after silking.Acid detergent lignin(ADL),cellulose(CEL),acid detergent fiber(ADF),neutral detergent fiber(NDF),and in vitro dry matter digestibility(IVDMD)were evaluated in a maize recombinant inbred line(RIL)population.ADL,CEL,ADF,and NDF gradually increased from 10 to 40 days after silking(DAS),and then they decreased.IVDMD initially decreased until 40 DAS,and then it increased slightly.Seventytwo QTLs were identified for the five traits,and each accounted for 3.48–24.04%of the phenotypic variation.Six QTL hotspots were found,and they were localized in the 1.08,2.04,2.07,7.03,8.05,and 9.03 bins of the maize genome.Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome,six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.In addition,26 conditional QTLs were detected in the five stages for all of the investigated traits.Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS,and at 50 DAS conditioned using the values of 40 DAS.These results indicated that cell wall-related traits are regulated by many genes,which are specifically expressed at different stages after silking.Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.展开更多
The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during...The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during plant development and adaptation but also to optimise their industrial applications. The analysis of cell wall compounds is complicated by their multiple molecular interactions. In this review, we present numerous methods to purify, characterise and quantify proteins, polysaccharides and lignin from the wall. Two kinds of approaches are detailed: the first presents in vitro methods which involve the breakdown of the molecular linkages between polymers thanking to chemical, physical and/or enzymatic treatments. The second approach describes in situ methods that allow the cell wall polymer characterisation thanking to many analytical techniques coupled with microscopy. If microscopy is the common point of all of them, their development is associated with improvement of analytical techniques, increasing their power of resolution.展开更多
The addition of p-coumaric acid (pCA) to lignin molecules is frequently found in members of the grass family. The role of this addition is not clearly understood, but is thought to potentially aid in the formation of ...The addition of p-coumaric acid (pCA) to lignin molecules is frequently found in members of the grass family. The role of this addition is not clearly understood, but is thought to potentially aid in the formation of syringyl-type lignin. This is because the incorporation is as a conjugate of pCA ester linked to sinapyl alcohol, a major component of lignin. The forage legume alfalfa (Medicago sativa L.) does not contain appreciable levels of pCA in its more heavily lignified stem tissues. The maize p-coumaryltransferase (pCAT) gene was used to transform alfalfa to determine its impact upon lignin composition and its potential to alter cell wall digestibility. A constitutive expression vector using the cassava vein mosaic virus (CsVMV) promoter was used to drive expression of maize pCAT in alfalfa. Expression of the pCAT transgene was detected in both leaves and stems. Though there was a range of pCAconcentration in transformed alfalfa stems (0.2 - 1.79 micrograms (μg)), this was a clear increase over bound pCA in control stems (0.15 - 0.2 mean = 0.17 micrograms (μg)). This did not lead to consistent responses concerning total lignin in the stem tissues. Leaf tissue, on the other hand, already has a relatively high level of pCA (0.85 - 1.2, mean = 0.99 micrograms (μg)) and those expressing pCAT gene showed on average a small increase, but there is a wide range of values among the transformants (0.38 - 1.55, mean = 1.06 micrograms (μg)). Lignin in leaves did not appear to be significantly impacted. However, incorporation of pCA into the wall appears to cause a shift in lignin composition. Testing the pCAT expressing stem cell walls for digestibility using a rumen in vitro system showed there was no change in the digestibility of the stem compared to empty vectors and control alfalfa stems. Although expression of pCAT gene in alfalfa changes the amount of wall bound pCA, it does not appear to change lignin levels or impact digestibility.展开更多
Sigmoid metastasis of renal cell carcinoma(RCC)is very rare.Herein we report a case of pathologically proven asynchronous abdominal wall and sigmoid metastases after a right nephrectomy.An 84-year-old man underwent ri...Sigmoid metastasis of renal cell carcinoma(RCC)is very rare.Herein we report a case of pathologically proven asynchronous abdominal wall and sigmoid metastases after a right nephrectomy.An 84-year-old man underwent right radical nephrectomy for clear cell renal cell carcinoma(ccRCC)13 years ago.Solitary contralateral abdominal wall metastasis was found for left abdominal mass 9 years after nephrectomy.The man experienced melena underwent resection of sigmoid colon tumor in February,2016.The postoperative pathological examinations revealed that the tumors were metastases of ccRCC.Recurrence more than 5 years after nephrectomy has been accepted as late recurrence by the majority of urologists now.Late recurrence is one of the specific biological behaviors of RCC.Asynchronous late recurrence of abdominal wall and sigmoid metastases in ccRCC has not been reported before.When patients have sigmoid mass after nephrectomy for RCC,doctors may consider the possibility of late recurrence.展开更多
Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes (MWCNTs).Methods Cultured macrophages (murine RAW264.7 cells) and alveolar epithelium cells type II ...Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes (MWCNTs).Methods Cultured macrophages (murine RAW264.7 cells) and alveolar epithelium cells type II (human A549 lung cells) were exposed to the blank control,DNA salt control,and the MWCNTs suspensions at 2.5,10,25,and 100 μg/mL for 24 h.Each treatment was evaluated by cell viability,cytotoxicity and oxidative stress.Results Overall,both cell lines had similar patterns in response to the cytotoxicity and oxidative stress of MWCNTs.DNA salt treatment showed no change compared to the blank control.In both cell lines,significant changes at the doses of 25 and 100 μg/mL treatments were found in cell viabilities,cytotoxicity,and oxidative stress indexes.The reactive oxygen species (ROS) generation was also found to be significantly higher at the dose of 10 μg/mL treatment,whereas no change was seen in most of the indexes.The ROS generation in both cell lines went up in minutes,reached the climax within an hour and faded down after several hours.Conclusion Exposure to MWCNTs resulted in a dose‐dependent cytotoxicity in cultured RAW264.7 cells and A549 cells,that was closely correlated to the increased oxidative stress.展开更多
The novel phage lysin PlySs2, is reported to be highly active against various bacteria, including staphylococci, streptococci and Listeria. However, the molecular mechanisms underlying its broad lytic spectrum remain ...The novel phage lysin PlySs2, is reported to be highly active against various bacteria, including staphylococci, streptococci and Listeria. However, the molecular mechanisms underlying its broad lytic spectrum remain to be established. In the present study, the lytic activity of the catalytic domain(CD, PlySc) and binding specificity of the cell wall binding domain(CBD, PlySb) of PlySs2 were examined. Our results showed that PlySc alone maintains very limited lytic activity. Enhanced green fluorescent protein(EGFP)-fused PlySb displayed high binding affinity to the streptococcal strains tested, including S.suis, S.dysgalactiae, and S.agalactiae, but not staphylococci, supporting its utility as a good CBD donor for streptococcal-targeted lysin engineering. EGFP-fused intact PlySs2 similarly displayed high affinity for streptococci, but not staphylococci. Notably, four truncated PlySb fragments showed no binding capacity. These findings collectively indicate that integrity of the PlySc and PlySb domains is an essential determinant of the broad lytic activity of PlySs2.展开更多
Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs ...Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs and sheaths undergo cell wall changes as cells transition to fully mature cell types. As is common in grasses during cell wall maturation, the lignin in the plant tissue is acylated with p-coumarates (pCA). This work characterizes cell walls in maize that make up leaf blade, leaf midrib, and sheath tissues corresponding to tissue development. Maize plants grown in the greenhouse were harvested;leaf, leaf midrib, and sheath tissues from nodes 9 through 14 tissues were analyzed for cell wall composition. Cell wall carbohydrates varied with the type of maize tissue, but there was little change within a tissue type among the different nodes. Lignin concentrations were lowest in the leaf blade (70 - 88 g·kg-1 CW) followed by the sheath (123 - 140 g·kg-1 CW) and highest in the midrib (140 - 168 g·kg-1 CW). Incorporation of pCA into cell walls paralleled the lignification. Ferulates (FA) remained relatively constant as a proportion of the cell wall (3.1 - 6.4 g·kg-1 CW) across nodes and across all tissue types. The range of FA was 3.8 vs 5.7 g·kg-1 CW averaged over all nodes with leaf blades being the lowest. Lignin composition did not change significantly with cell wall maturation within a given tissue type. The aerial portions of maize plants excluding the stem showed little difference in cell wall composition along the different nodes. Higher levels of ferulates were found in the sheath and leaf midrib compared to the leaf blade tissues. Leaf midribs from the upper nodes of the plant contained the highest levels of lignin. Perhaps a reflection of the function to keep leaves extended and in an upward angle to help maximize photosynthetic capacity.展开更多
Eucommia ulmoides male flowers are rich in secondary metabolite,which have anti-tumor,sedative hypnotic,hypotensive,hypolipidemic,anti-fatigue,bacteriostatic,antioxidant and anti-aging effects.The conventional process...Eucommia ulmoides male flowers are rich in secondary metabolite,which have anti-tumor,sedative hypnotic,hypotensive,hypolipidemic,anti-fatigue,bacteriostatic,antioxidant and anti-aging effects.The conventional processing of E.ulmoides male flowers leads to the loss of nutrients and active ingredients.In recent years,cell wall breaking technology has been developed and utilized in various fields such as traditional Chinese medicine,good,chemical industry and biology.In order to promote the development of the E.ulmoides industry,the cell wall breaking technology and its characteristics are reviewed,and the application advantages of the cell wall breaking technology in the male flowers of E.ulmoides are discussed,and the prospect of the cell wall breaking of E.ulmoides is proposed in this article.展开更多
Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial syste...Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.展开更多
The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is feruli...The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is ferulic acid that is incorporated into cell walls as an ester linked residue on arabinoxylans. Ferulates can become coupled to each other and to lignin forming a highly cross-linked matrix of carbohydrates and lignin. Seedling ferulate ester mutants (sfe) were produced in maize using the transposon system and evaluated in feeding trials. The work described here was undertaken to characterize changes in the ferulate cross-linked nature as well as other components of the corn cell wall matrix in leaf, sheath and stem tissues. Total ferulates decreased modestly due to the mutation and were more apparent in leaf tissue (16% - 18%) compared to sheath (+5 to?-6% change) and stem (8% - 9% decrease). The most significant changes were in the ether linked ferulates to lignin, both monomer and dehydrodiferulates (14% to 38% decrease). Other characteristics of the cell wall (lignin, neutral sugar composition) also showed modest changes. The change in total ferulates was modest, but led to improved animal performance. These findings suggest that relatively small changes can have a significant impact upon how well plant materials can be broken down and utilized by ruminants such as dairy cows.展开更多
Nascent pectin and glucuronoxylan were prepared from membrane-bound enzymes obtained from pea epicotyls. They had previously been shown to exhibit a protein- and pH-dependent pattern of binding to cell wall ghosts and...Nascent pectin and glucuronoxylan were prepared from membrane-bound enzymes obtained from pea epicotyls. They had previously been shown to exhibit a protein- and pH-dependent pattern of binding to cell wall ghosts and to xy-loglucan extracted from cell walls prepared from pea epicotyls;maximum binding required a pH of 3-4, and the pres-ence of cell wall proteins, namely assemblins. To determine whether wall polysaccharides deposited in cell walls be-have in the same manner as nascent polymers, radioactively labeled EDTA-soluble polymers were prepared from newly-deposited pea epicotyl cell walls. Different enzyme treatments followed by column chromatography, in addition to complete acid hydrolysis followed by paper and thin layer chromatography, indicated the presence of pectin, to-gether with smaller amounts of glucuronoxylan, in this EDTA-soluble extract. These radioactively labeled polysaccha-rides were found to bind to cell wall ghosts and to xyloglucan extracted from the second and third internodes of pea epicotyls cell walls in a pH-dependent manner, similar to the binding pattern obtained with nascent polymers. Maxi-mum binding occurred at pH 3-4, and also required the presence of protein.展开更多
基金This study was sponsored by the National Natural Science Foundation of China(grant no.82172224).
文摘Diabetic foot ulcers are one of the most severe complications of diabetes that have imposed great financial and psychological burdens on diabetic patients.A Nocardia rubra cell wall skeleton(Nr-CWS)can be externally applied to accelerate wound healing.However,its clinical application has not yet been reported.Herein,we report two patients with diabetic foot ulcers treated with Nr-CWS.After wound debridement,the wound was covered with a sterile cotton ball infiltrated with an Nr-CWS that was diluted with 2.0 mL of saline.The covers were changed every two days until complete wound healing occurred.The two wounds healed after 3 and 12 weeks,respectively.This article aims to provide a new treatment for diabetic foot ulcers,with the hope that physicians may consider an Nr-CWS as a complementary method for the treatment of chronic wounds.
文摘Objective:To observe and compare the curative effect between the intrapleural-chemotherapy combined Nocardia rubra cell wall skeleton-injection and the Nocardia rubra cell wall skeleton-injection after control of the malignant pleural effusion by chemotherapy.Methods:Every time after elimination of pleural effusion,we injected DDP and Nocardia rubra cell wall skeleton at the same time into pleural cavity;or after we emplaced an improved central vena catheter into pleural cavity then took out closed-drainage or eliminated the pleural effusion every day,then injected 5-FU 0.5 qd intrapleural-space.After the malignant pleural effusion had being controlled,800μg Nocardia rubra cell wall skeleton was injected intrapleural-space. (We call it as"improved following-therapy").Results:Using the improved following-therapy,the control rate of malignant pleural effusion increased:CR+PR,79.07%>65.79%(P<0.05),and the incidence rate of the encapsulated pleural effusion that would impact on patient’s respiratory faction decreased.Conclusion:Giving chemotherapy after closed-drainage or immediately after taking out pleural effusion everyday,then giving biotherapy after pleural effusion had been controlled,the curative effect would be enhanced and the side-reaction would be reduced.
基金the National Natural Science Foundation of China(31701546)the Fundamental Research Funds for the Central Universities of China(2019ZD40)+5 种基金the 111 Project(B17018)for financial supportPearl River Talent Recruitment Program of Guangdong Province(2017GC010229)the Pearl River Nova Program of Guangzhou(201906010079)the National Natural Science Foundation of China(32001691)the special fund for scientific innovation strategyconstruction of high-level academy of agriculture science(R2019YJYB1001)the Application-oriented Projects of Guangdong Province(2017B020232002)。
文摘Natural foods,such as whole pulses,are recommended in the dietary guidelines of the US and China.The plant cell wall structure in whole pulses has important implications for the nutritional functionalities of starch.In this study,garbanzo bean cells with varying degrees of cell wall integrity were subjected to dry heat treatment(DHT)and used to elucidate the food structure-starch digestion properties of pulse food.The morphological features suggested that all cell samples do not exhibit remarkable changes after being subjected to DHT.Molecular rearrangement and the crystallite disruption of starch granules entrapped in cells occurred during DHT as assessed by the crystal structure and thermal properties.DHT decreased the inhibitory effects of enzymes of both the soluble and insoluble components,but the digestion rate and extent of slightly and highly damaged cell samples did not exhibit significant differences compared with their native counterparts.We concluded that the starch digestion of pulse cotyledon cells is primarily determined by the intactness of the cellular structure.This study reveals the role of food structure on the ability to retain the desirable nutritional properties of starch after subjection to physical modification.
基金supported by the Key Research and Development Program of Zhejiang Province(2021C02056,2021C02063-6)the National Key Research and Development Program of China(2021YFD1200503)+1 种基金the Fundamental Research Funds for Central Public Welfare Research Institutes of China National Rice Research Institute(CPSIBRF-CNRRI-202101)Chinese Academy of Agricultural Sciences(CAAS-ASTIP-201X-CNRRI)。
文摘Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a novel brittle culm 25(bc25)mutant with reduced growth and partial sterility.BC25 encodes an UDP-glucuronic acid decarboxylase involved in cellulose synthesis and belongs to the UXS family.A single-nucleotide mutation in BC25 accounts for its altered cell morphology and cellwall composition.Transmission electron microscopy analysis showed that the thickness of the secondary cell wall was reduced in bc25.Monosaccharide analysis revealed significant increases in content of rhamnose and arabinose but not of other monosaccharides,indicating that BC25 was involved in xylose synthesis with some level of functional redundancy.Enzymatic assays suggested that BC25 functions with high activity to interconvert UDP-glucuronic acid(UDP-Glc A)and UDP-xylose.GUS staining showed that BC25 was ubiquitously expressed with higher expression in culm,root and sheath,in agreement with that shown by quantitative real-time(q RT)-PCR.RNA-seq further suggested that BC25 is involved in sugar metabolism.We conclude that BC25 strongly influences rice cell wall formation.
基金funded by the National Key Research and Development Program of China(2021YFF1000302)Fundamental Research Funds for the Central Universities of China(06500136)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(FRF-IDRY-20-038).
文摘Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is known about molecular mechanisms underlying anther cell elongation.Here,we found that properly activated cell elongation regulators at transcriptional levels in loss-of-function ZmMs33 mutant(ms33-6038)anthers failed to promote maize anther elongation.ZmMs33 deficiency disrupted metabolic homeostasis mainly by inhibiting both photosynthesis in anther endothecium and lipid accumulation in anther tapetum.Importantly,ms33-6038 anthers displayed ectopic,premature and excessive secondary cell wall thickening in anther middle layer,which constrained cell elongation structurally and blocked nutrient flows across different anther wall layers.The metabolic disorder was only found in ms33-6038 mutant rather than several representative male-sterility lines at transcriptional and post-translational levels.Collectively,the disordered metabolisms and blocked nutrient flows defeated the activated cell elongation regulators,and finally inhibited anther elongation and growth with a unique‘‘idling effect”in ms33-6038 mutant.
基金supported by the Foundation for Distinguished Young Scholars of Jiangsu Province,China(Grant No.BK20190050)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY22C130004)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015250)。
文摘Phosphorus(P) starvation in rice facilitates the reutilization of root cell wall P by enhancing the pectin content. NaCl modulates pectin content, however, it is still unknown whether NaCl is also involved in the process of pectin regulated cell wall P remobilization in rice under P starved conditions. In this study, we found that 10 mmol/L NaCl increased the shoot and root biomasses under P deficiency to a remarkable extent, in company with the elevated shoot and root soluble P contents in rice. Further analysis indicated that exogenous NaCl enhanced the root cell wall P mobilization by increasing the pectin methylesterase activity and uronic acid content in pectin suggesting the involvement of NaCl in the process of cell wall P reutilization in P starved rice roots. Additionally, exogenous NaCl up-regulated the expression of P transporter OsPT6, which was induced by P deficiency, suggesting that NaCl also facilitated the P translocation prominently from root to shoot in P starved rice. Moreover, exogenous abscisic acid(ABA) can reverse the NaCl-mediated mitigation under P deficiency, indicating the involvement of ABA in the NaCl regulated root cell wall P reutilization. Taken together, our results demonstrated that NaCl can activate the reutilization of root cell wall P in P starved rice, which is dependent on the ABA accumulation pathway.
基金supported by the China Agriculture Research System of MOF and MARA (CARS-27)
文摘Fruit development and ripening is a complex procedure(Malus×domestica Borkh.)and can be caused by various factors such as cell structure,cell wall components,and cell wall hydrolytic enzymes.In our study,we focused on the variations in fruit firmness,cell wall morphology and components,the activity of cell wall hydrolytic enzymes and the expression patterns of associated genes during fruit development in two different types of apple cultivars,the hard-crisp cultivar and the loose-crisp cultivar.In this paper,the aim was to find out the causes of the texture variations between the different type cultivars.Cell wall materials(CWMs),hemicellulose and cellulose content were strongly associated with variations in fruit firmness during the fruit development.The content of water soluble pectin(WSP)and chelator soluble pectin(CSP)gradually increased,while the content of ionic soluble pectin(ISP)showed inconsistent trends in the four cultivars.The activities of polygalacturonase(PG),β-galactosidase(β-gal),cellulase(CEL),and pectate lyase(PL)gradually increased in four cultivars.And the activities of PG,β-gal,and CEL were higher in‘Fuji’and‘Honeycrisp’fruit with the fruit development,while the activity of PL of‘Fuji’and‘Honeycrisp’was lower than that of‘ENVY’and‘Modi’.Both four cultivars of fruit cells progressively became bigger as the fruit expanded,with looser cell arrangements and larger cell gaps.According to the qRT-PCR,the relative expression levels of MdACO and Mdβ-gal were notably enhanced.Our study showed that there were large differences in the content of ISP and hemicellulose,the activity of PL and the relative expression of Mdβ-gal between two different types of apple cultivars,and these differences might be responsible for the variations in the texture of the four cultivars.
基金supported by the Nanfan Special Project of Chinese Academy of Agricultural Sciences (Grant No. ZDXM2315)the National Natural Science Foundation of China (Grant Nos. 32372125, 31861143006, and 32188102)+2 种基金Special Support Program of Chinese Academy of Agricultural Sciences (Grant NO. NKYCLJ-C-2021-015)Specific Research Fund of the Innovation Platform for Academicians of Hainan Province2023 College Student Innovation and Entrepreneurship Project of Jiangxi Agricultural University, China (Grant No. S202310410095)
文摘The morphological development of rice(Oryza sativa L.)leaves is closely related to plant architecture,physiological activities,and resistance.However,it is unclear whether there is a co-regulatory relationship between the morphological development of leaves and adaptation to drought environment.In this study,a drought-sensitive,roll-enhanced,and narrow-leaf mutant(renl1)was induced from a semi-rolled leaf mutant(srl1)by ethyl methane sulfonate(EMS),which was obtained from Nipponbare(NPB)through EMS.Map-based cloning and functional validation showed that RENL1 encodes a cellulose synthase,allelic to NRL1/OsCLSD4.The RENL1 mutation resulted in reduced vascular bundles,vesicular cells,cellulose,and hemicellulose contents in cell walls,diminishing the water-holding capacity of leaves.In addition,the root system of the renl1 mutant was poorly developed and its ability to scavenge reactive oxygen species(ROS)was decreased,leading to an increase in ROS after drought stress.Meanwhile,genetic results showed that RENL1 and SRL1 synergistically regulated cell wall components.Our results revealed a theoretical basis for further elucidating the molecular regulation mechanism of cellulose on rice drought tolerance,and provided a new genetic resource for enhancing the synergistic regulation network of plant type and stress resistance,thereby realizing simultaneous improvement of multiple traits in rice.
基金supported by the National Key Research and Development Program of China(2017YFD0101201 and2016YFD0101002)the Chinese Academy of Agricultural Sciences through the Agricultural Science and Technology Innovation Program(CAAS-ASTIP-2017-TRICAAS)National Engineering Laboratory for Crop Molecular Breeding
文摘The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies have focused on high-oil cultivars with high grain and straw quality.Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality.In the present study,a high-oil inbred line(By804)was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines(RILs).The phenotypes of six cell-wall-related traits were recorded,and QTL analysis was performed with a genetic map constructed with SNP markers.All traits were significantly correlated with one another and showed high broad-sense heritability.Of 20 QTLs mapped,the QTL associated with each trait explained 10.0%–41.1%of phenotypic variation.Approximately half of the QTL each explained over 10%of the phenotypic variation.These results provide a theoretical basis for improving maize forage quality by marker-assisted selection.
基金the National Natural Science Foundation of China(31801367)the National Key Research and Development Program of China(2016YFD0101200)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences.
文摘Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting the structure and strength of the cell wall.To explore cell wall development during secondary cell wall lignification in maize stalks,conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci(QTLs)of the cell wall components and digestibility traits during five growth stages after silking.Acid detergent lignin(ADL),cellulose(CEL),acid detergent fiber(ADF),neutral detergent fiber(NDF),and in vitro dry matter digestibility(IVDMD)were evaluated in a maize recombinant inbred line(RIL)population.ADL,CEL,ADF,and NDF gradually increased from 10 to 40 days after silking(DAS),and then they decreased.IVDMD initially decreased until 40 DAS,and then it increased slightly.Seventytwo QTLs were identified for the five traits,and each accounted for 3.48–24.04%of the phenotypic variation.Six QTL hotspots were found,and they were localized in the 1.08,2.04,2.07,7.03,8.05,and 9.03 bins of the maize genome.Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome,six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.In addition,26 conditional QTLs were detected in the five stages for all of the investigated traits.Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS,and at 50 DAS conditioned using the values of 40 DAS.These results indicated that cell wall-related traits are regulated by many genes,which are specifically expressed at different stages after silking.Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.
文摘The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during plant development and adaptation but also to optimise their industrial applications. The analysis of cell wall compounds is complicated by their multiple molecular interactions. In this review, we present numerous methods to purify, characterise and quantify proteins, polysaccharides and lignin from the wall. Two kinds of approaches are detailed: the first presents in vitro methods which involve the breakdown of the molecular linkages between polymers thanking to chemical, physical and/or enzymatic treatments. The second approach describes in situ methods that allow the cell wall polymer characterisation thanking to many analytical techniques coupled with microscopy. If microscopy is the common point of all of them, their development is associated with improvement of analytical techniques, increasing their power of resolution.
文摘The addition of p-coumaric acid (pCA) to lignin molecules is frequently found in members of the grass family. The role of this addition is not clearly understood, but is thought to potentially aid in the formation of syringyl-type lignin. This is because the incorporation is as a conjugate of pCA ester linked to sinapyl alcohol, a major component of lignin. The forage legume alfalfa (Medicago sativa L.) does not contain appreciable levels of pCA in its more heavily lignified stem tissues. The maize p-coumaryltransferase (pCAT) gene was used to transform alfalfa to determine its impact upon lignin composition and its potential to alter cell wall digestibility. A constitutive expression vector using the cassava vein mosaic virus (CsVMV) promoter was used to drive expression of maize pCAT in alfalfa. Expression of the pCAT transgene was detected in both leaves and stems. Though there was a range of pCAconcentration in transformed alfalfa stems (0.2 - 1.79 micrograms (μg)), this was a clear increase over bound pCA in control stems (0.15 - 0.2 mean = 0.17 micrograms (μg)). This did not lead to consistent responses concerning total lignin in the stem tissues. Leaf tissue, on the other hand, already has a relatively high level of pCA (0.85 - 1.2, mean = 0.99 micrograms (μg)) and those expressing pCAT gene showed on average a small increase, but there is a wide range of values among the transformants (0.38 - 1.55, mean = 1.06 micrograms (μg)). Lignin in leaves did not appear to be significantly impacted. However, incorporation of pCA into the wall appears to cause a shift in lignin composition. Testing the pCAT expressing stem cell walls for digestibility using a rumen in vitro system showed there was no change in the digestibility of the stem compared to empty vectors and control alfalfa stems. Although expression of pCAT gene in alfalfa changes the amount of wall bound pCA, it does not appear to change lignin levels or impact digestibility.
文摘Sigmoid metastasis of renal cell carcinoma(RCC)is very rare.Herein we report a case of pathologically proven asynchronous abdominal wall and sigmoid metastases after a right nephrectomy.An 84-year-old man underwent right radical nephrectomy for clear cell renal cell carcinoma(ccRCC)13 years ago.Solitary contralateral abdominal wall metastasis was found for left abdominal mass 9 years after nephrectomy.The man experienced melena underwent resection of sigmoid colon tumor in February,2016.The postoperative pathological examinations revealed that the tumors were metastases of ccRCC.Recurrence more than 5 years after nephrectomy has been accepted as late recurrence by the majority of urologists now.Late recurrence is one of the specific biological behaviors of RCC.Asynchronous late recurrence of abdominal wall and sigmoid metastases in ccRCC has not been reported before.When patients have sigmoid mass after nephrectomy for RCC,doctors may consider the possibility of late recurrence.
基金supported partly by a grant from Shanghai Science and Technology Committee International Collaboration Program (Project No. 055207078)
文摘Objective To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes (MWCNTs).Methods Cultured macrophages (murine RAW264.7 cells) and alveolar epithelium cells type II (human A549 lung cells) were exposed to the blank control,DNA salt control,and the MWCNTs suspensions at 2.5,10,25,and 100 μg/mL for 24 h.Each treatment was evaluated by cell viability,cytotoxicity and oxidative stress.Results Overall,both cell lines had similar patterns in response to the cytotoxicity and oxidative stress of MWCNTs.DNA salt treatment showed no change compared to the blank control.In both cell lines,significant changes at the doses of 25 and 100 μg/mL treatments were found in cell viabilities,cytotoxicity,and oxidative stress indexes.The reactive oxygen species (ROS) generation was also found to be significantly higher at the dose of 10 μg/mL treatment,whereas no change was seen in most of the indexes.The ROS generation in both cell lines went up in minutes,reached the climax within an hour and faded down after several hours.Conclusion Exposure to MWCNTs resulted in a dose‐dependent cytotoxicity in cultured RAW264.7 cells and A549 cells,that was closely correlated to the increased oxidative stress.
基金supported by the National Natural Science Foundation of China (No. 31400126)Basic Research Program of the Ministry of Science and Technology of China (No. 2012CB721102)+2 种基金Chinese Academy of Sciences (No. KJZD-EW-L02)Open Research Fund Program of the State Key Laboratory of Virology of China (No. 2014IOV002)Key Laboratory of Emerging Infectious Diseases and Biosafety, Wuhan
文摘The novel phage lysin PlySs2, is reported to be highly active against various bacteria, including staphylococci, streptococci and Listeria. However, the molecular mechanisms underlying its broad lytic spectrum remain to be established. In the present study, the lytic activity of the catalytic domain(CD, PlySc) and binding specificity of the cell wall binding domain(CBD, PlySb) of PlySs2 were examined. Our results showed that PlySc alone maintains very limited lytic activity. Enhanced green fluorescent protein(EGFP)-fused PlySb displayed high binding affinity to the streptococcal strains tested, including S.suis, S.dysgalactiae, and S.agalactiae, but not staphylococci, supporting its utility as a good CBD donor for streptococcal-targeted lysin engineering. EGFP-fused intact PlySs2 similarly displayed high affinity for streptococci, but not staphylococci. Notably, four truncated PlySb fragments showed no binding capacity. These findings collectively indicate that integrity of the PlySc and PlySb domains is an essential determinant of the broad lytic activity of PlySs2.
文摘Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades including the midribs and sheaths undergo cell wall changes as cells transition to fully mature cell types. As is common in grasses during cell wall maturation, the lignin in the plant tissue is acylated with p-coumarates (pCA). This work characterizes cell walls in maize that make up leaf blade, leaf midrib, and sheath tissues corresponding to tissue development. Maize plants grown in the greenhouse were harvested;leaf, leaf midrib, and sheath tissues from nodes 9 through 14 tissues were analyzed for cell wall composition. Cell wall carbohydrates varied with the type of maize tissue, but there was little change within a tissue type among the different nodes. Lignin concentrations were lowest in the leaf blade (70 - 88 g·kg-1 CW) followed by the sheath (123 - 140 g·kg-1 CW) and highest in the midrib (140 - 168 g·kg-1 CW). Incorporation of pCA into cell walls paralleled the lignification. Ferulates (FA) remained relatively constant as a proportion of the cell wall (3.1 - 6.4 g·kg-1 CW) across nodes and across all tissue types. The range of FA was 3.8 vs 5.7 g·kg-1 CW averaged over all nodes with leaf blades being the lowest. Lignin composition did not change significantly with cell wall maturation within a given tissue type. The aerial portions of maize plants excluding the stem showed little difference in cell wall composition along the different nodes. Higher levels of ferulates were found in the sheath and leaf midrib compared to the leaf blade tissues. Leaf midribs from the upper nodes of the plant contained the highest levels of lignin. Perhaps a reflection of the function to keep leaves extended and in an upward angle to help maximize photosynthetic capacity.
基金Supported by Project of Department of Education of Hunan Province(13CY017)
文摘Eucommia ulmoides male flowers are rich in secondary metabolite,which have anti-tumor,sedative hypnotic,hypotensive,hypolipidemic,anti-fatigue,bacteriostatic,antioxidant and anti-aging effects.The conventional processing of E.ulmoides male flowers leads to the loss of nutrients and active ingredients.In recent years,cell wall breaking technology has been developed and utilized in various fields such as traditional Chinese medicine,good,chemical industry and biology.In order to promote the development of the E.ulmoides industry,the cell wall breaking technology and its characteristics are reviewed,and the application advantages of the cell wall breaking technology in the male flowers of E.ulmoides are discussed,and the prospect of the cell wall breaking of E.ulmoides is proposed in this article.
文摘Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.
文摘The cross-linked nature of plant cell walls provides structural integrity for continued growth and development, but limits degradation and utilization by ruminants. In grasses a major cross-linking component is ferulic acid that is incorporated into cell walls as an ester linked residue on arabinoxylans. Ferulates can become coupled to each other and to lignin forming a highly cross-linked matrix of carbohydrates and lignin. Seedling ferulate ester mutants (sfe) were produced in maize using the transposon system and evaluated in feeding trials. The work described here was undertaken to characterize changes in the ferulate cross-linked nature as well as other components of the corn cell wall matrix in leaf, sheath and stem tissues. Total ferulates decreased modestly due to the mutation and were more apparent in leaf tissue (16% - 18%) compared to sheath (+5 to?-6% change) and stem (8% - 9% decrease). The most significant changes were in the ether linked ferulates to lignin, both monomer and dehydrodiferulates (14% to 38% decrease). Other characteristics of the cell wall (lignin, neutral sugar composition) also showed modest changes. The change in total ferulates was modest, but led to improved animal performance. These findings suggest that relatively small changes can have a significant impact upon how well plant materials can be broken down and utilized by ruminants such as dairy cows.
文摘Nascent pectin and glucuronoxylan were prepared from membrane-bound enzymes obtained from pea epicotyls. They had previously been shown to exhibit a protein- and pH-dependent pattern of binding to cell wall ghosts and to xy-loglucan extracted from cell walls prepared from pea epicotyls;maximum binding required a pH of 3-4, and the pres-ence of cell wall proteins, namely assemblins. To determine whether wall polysaccharides deposited in cell walls be-have in the same manner as nascent polymers, radioactively labeled EDTA-soluble polymers were prepared from newly-deposited pea epicotyl cell walls. Different enzyme treatments followed by column chromatography, in addition to complete acid hydrolysis followed by paper and thin layer chromatography, indicated the presence of pectin, to-gether with smaller amounts of glucuronoxylan, in this EDTA-soluble extract. These radioactively labeled polysaccha-rides were found to bind to cell wall ghosts and to xyloglucan extracted from the second and third internodes of pea epicotyls cell walls in a pH-dependent manner, similar to the binding pattern obtained with nascent polymers. Maxi-mum binding occurred at pH 3-4, and also required the presence of protein.
