scholarly journals Immunocytological Analysis of Potato Tuber Periderm and Changes in Pectin and Extensin Epitopes Associated with Periderm Maturation

2005 ◽  
Vol 130 (6) ◽  
pp. 936-942 ◽  
Author(s):  
Robert P. Sabba ◽  
Edward C. Lulai
Keyword(s):  
Monoclonal Antibody ◽  
Potato Tuber ◽  
Cell Walls ◽  
New Technologies ◽  
Cell Types ◽  
Rhamnogalacturonan I ◽  
Development Of Resistance ◽  
Lateral Meristem ◽  
Tuber Periderm ◽  
Concurrent Development

Potato (Solanum tuberosum L.) periderm forms a barrier at the surface of the tuber that protects it from infection and dehydration. Immature periderm is susceptible to excoriation (skinning injury), which results in costly storage loses and market quality defects. The periderm consists of three different cell types: phellem (skin), phellogen (cork cambium), and phelloderm (parenchyma-like cells). The phellogen serves as a lateral meristem for the periderm and is characterized by thin radial walls that are labile to fracture while the periderm is immature and the phellogen is actively dividing, thus rendering the tuber susceptible to excoriation. As the periderm matures the phellogen becomes inactive, its cell walls thicken and become resistant to fracture, and thus the tuber becomes resistant to excoriation. Little is known about the changes in cell wall polymers that are associated with tuber periderm maturation and the concurrent development of resistance to excoriation. Various changes in pectins (galacturonans and rhamnogalacturonans) and extensin may be involved in this maturational process. The objectives of this research were to compare immunolabeling of homogalacturonan (HG) epitopes to labeling of rhamnogalacturonan I (RG-I) and extensin epitopes to better understand the depositional patterns of these polymers in periderm cell walls and their involvement in tuber periderm maturation. Immunolabeling with the monoclonal antibodies JIM5 and JIM7 (recognizing a broad range of esterified HG) confirmed that HG epitopes are lacking in phellogen walls of immature periderm, but increased greatly upon maturation of the periderm. Labeling of a (1,4)-β-galactan epitope found in RG-I and recognized by the monoclonal antibody LM5 was abundant in phelloderm cell walls, but sparse in most phellem cell walls. LM5 labeling was very sparse in the walls of meristematically active phellogen cells of immature periderm, but increased dramatically upon periderm maturation. Deposition of a (1,5)-α-l-arabinan epitope found in RG-I and recognized by LM6 was abundant in phelloderm and phellogen cell walls, but was sparse in phellem cell walls. LM6 labeling of phellogen walls did not change upon periderm maturation, indicating that different RG-1 epitopes are regulated independently during maturation of the periderm. Labeling with the monoclonal antibody LM1 for an extensin epitope implied that extensin is lacking in phellem cell walls, but is abundant in phelloderm cell walls. Phellogen cell walls did not label with LM1 in immature periderm, but were abundantly labeled with LM1 in mature periderm. These immunolabeling studies identify pectin and extensin depositions as likely biochemical processes involved in the thickening and related strengthening of phellogen walls upon inactivation of the phellogen layer as a lateral meristem and maturation of the periderm in potato tuber. These results provide unique and new insight into the identities of some of the biological processes that may be targeted in the development of new technologies to enhance resistance to tuber skinning injury for improved harvest, handling and storage properties.

scholarly journals STRUCTURAL AND CHEMICAL CHARACTERISTIC OF PECTIN FROM PICEA ABIES GREENERY

2020 ◽  
pp. 59-71
Author(s):  
Evgeniy Gennad'yevich Shakhmatov ◽  
Elena Nikolayevna Makarova
Keyword(s):  
Cell Walls ◽  
New Technologies ◽  
Chemical Characteristic ◽  
Structural Features ◽  
Exchange Chromatography ◽  
Raw Material ◽  
Rhamnogalacturonan I ◽  
Wood Processing ◽  
Potential Source ◽  
Pectin Substances

The present work aimed to determine structural features of polysaccharides derived from the P. abies foliage by extraction with a (NH4)2C2O4 solution. The isolated polysaccharide was studied in detail by the methods of ion exchange chromatography, partial acidic hydrolys and NMR spectroscopy. It was shown that this polysaccharide contained polymers of various structures. The major constituents of PAO were low-methoxyl and low-acetylated 1,4-a-D-galacturonan and by minor parts of partly 2-O- and/or 3-O- acetylated rhamnogalacturonan-I (RG-I). The side carbohydrate chains of the branched region of RG-I were represented predominantly by highly branched 1,5-a-L-arabinan and minor portions of 1,4-β-D-galactan. In addition to the dominant pectins, polysaccharide PAO contained binding glycans of the glucomannans class, which indicated a close interaction of these polysaccharides in the cell walls. Thus, the structural features of pectin woody P. abies, extracted with a solution of (NH4)2C2O4, were first determined. It can be concluded that P. abies woody greens, a large tonnage waste from the wood processing industry, can be considered as a potential source of pectin substances. The results of studying the structure of components of woody green P. abies can be the basis for the development and improvement of new technologies for the integrated use of this raw material.

scholarly journals Cell wall polymers in the Phaeoceros placenta reflect developmental and functional differences across generations

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
JASON S. HENRY ◽  
ROBERTO LIGRONE ◽  
KEVIN C. VAUGHN ◽  
RENEE A. LOPEZ ◽  
KAREN S. RENZAGLIA
Keyword(s):  
Cell Wall ◽  
Calcium Binding ◽  
Cell Walls ◽  
Cell Types ◽  
Transfer Cells ◽  
Calcofluor White ◽  
Placental Cell ◽  
Rhamnogalacturonan I ◽  
Cell Wall Polymers ◽  
Two Generations

The placenta of hornworts is unique among bryophytes in the restriction of transfer cells that are characterized by elaborate wall labyrinths to the gametophyte generation. During development, cells around the periphery of the sporophyte foot elongate, forming smooth-walled haustorial cells that interdigitate with gametophyte cells. Using immunogold labeling with 22 antibodies to diverse cell wall polymers, we examined compositional differences in the developmentally and morphologically distinct cell walls of gametophyte transfer cells and sporophyte haustorial cells in the placenta of Phaeoceros. As detected by Calcofluor White fluorescence, cellulose forms the cell wall scaffolding in cells on both sides of the placenta. Homogalacturonan (HG) and rhamnogalacturonan I (RG-I) pectins are abundant in both cell types, and haustorial cells are further enriched in methyl-esterified HGs. The abundance of pectins in placental cell walls is consistent with the postulated roles of these polymers in cell wall porosity and in maintaining an acidic apoplastic pH favorable to solute transport. Xyloglucan hemicellulose, but not mannans or glucuronoxylans, are present in cell walls at the interface between the two generations with a lower density in gametophytic wall ingrowths. Arabinogalactan proteins (AGPs) are diverse along the plasmalemma of placental cells and are absent in surrounding cells in both generations. AGPs in placental cell walls may play a role in calcium binding and release associated with signal transduction as has been speculated for these glycoproteins in other plants. Callose is restricted to thin areas in cell walls of gametophyte transfer cells. In contrast to studies of transfer cells in other systems, no reaction to the JIM12 antibody against extensin was observed in Phaeoceros.

Batch-based agile program management approach for coordinating IT multi-project concurrent development

2021 ◽  
pp. 1063293X2110152
Author(s):  
Qing Yang ◽  
Yingxin Bi ◽  
Qinru Wang ◽  
Tao Yao
Keyword(s):  
Software Development ◽  
New Technologies ◽  
Program Management ◽  
Agile Development ◽  
Management Approach ◽  
Development Projects ◽  
Project Development ◽  
Concurrent Development ◽  
Communication And Coordination ◽  
Development Practice

Software development projects have undergone remarkable changes with the arrival of agile development approaches. Many firms are facing a need to use these approaches to manage entities consisting of multiple projects (i.e. programs) simultaneously and efficiently. New technologies such as big data provide a huge power and rich demand for the IT application system of the commercial bank which has the characteristics of multiple sub-projects, strong inter-project correlation, and numerous project participating teams. Hence, taking the IT program management of a bank in China as a case, we explore the methods to solve the problems in multi-project concurrent development practice through integrating the ideas of program and batch management. First, to coordinate the multi-project development process, this paper presents the batch-based agile program management approach that synthesizes concurrent engineering with agile methods. And we compare the application of batch management between software development projects and manufacturing process. Further, we analyze the concurrent multi-project development practice in the batch-based agile program management, including the overlapping between stages, individual project’s activities, and multiple projects based on common resources and environment to stimulate the knowledge transfer. Third, to facilitate the communication and coordination of batch-based program management, we present the double-level responsibility organizational structure of batch management.

Interpolation of microtubules into cortical arrays during cell elongation and differentiation in roots of Azolla pinnata

1979 ◽  
Vol 37 (1) ◽  
pp. 411-442
Author(s):  
A.R. Hardham ◽  
B.E. Gunning
Keyword(s):  
Cell Differentiation ◽  
Cell Walls ◽  
Unit Length ◽  
Cell Types ◽  
High Rate ◽  
Wall Thickening ◽  
Cortical Microtubules ◽  
Azolla Pinnata ◽  
Outer Cortex ◽  
Cortical Cells

Longitudinal sections of roots of Azolla pinnata R. Br. were prepared for electron microscopy so that cortical microtubules could be counted along the longitudinal walls in cell files in the endodermis, pericycle, and inner and outer cortex, and in sieve and xylem elements. With the exception of the xylem, where there are no transverse cell divisions, each file of cells commences with its initial cell and then possesses a zone of concomitant cell expansion and transverse cell division, followed, after completion of the divisions, by a zone of terminal cell differentiation. The cells augment their population of cortical microtubules as they elongate and divide, showing a net increase of up to 0.6 micron of polymerized microtubule length per min. Two main sub-processes were found: (i) When a longitudinal wall is first formed it is supplied with a higher number of microtubules per unit length of wall than it will have later, when it is being expanded. This initial quota becomes diluted as the second sub-process commences. (ii) The cells interpolate new microtubules at a rate which is characteristic of the cell, and, in the endodermis, of the face of the cell, while the cell elongates. Most cell types thus maintain a set density of cortical microtubules while they elongate and divide. Comparisons of endodermal cells in untreated controls, and roots that had been treated with colchicine, low temperature, or high pressure indicate that the initial quota of microtubules, and the later interpolations, and differentially sensitive to microtuble perturbations. Three types of behaviour, all related to changes in the cell walls, were noted as cortex, xylem and sieve element cells entered their respective phases of cell differentiation. The cortical cells expanded in all dimensions, and the interpolation of microtubules diminished or ceased. The sieve elements continued to elongate, and interpolated at a high rate, reaching unusually high densities of microtubules when the cell walls were being thickened. During this period a net increase of 2.0 micron of polymerized microtubule length per min was calculated. Thereafter interpolation ceased and the density of microtubules declined. The sample applied to developing xylem except that, because wall-thickening is localized rather than widespread, the rise and subsequent fall in the density of microtubules was less marked. The data are discussed in relation to the participation of microtubules in wall deposition and to the hypothesis that cortical microtubules arise in discrete zones along the edges of cells.

scholarly journals Spatial and Temporal Changes in PD-L1 Expression in Cancer: The Role of Genetic Drivers, Tumor Microenvironment and Resistance to Therapy

2020 ◽  
Vol 21 (19) ◽  
pp. 7139 ◽  
Author(s):  
Elena Shklovskaya ◽  
Helen Rizos
Keyword(s):  
Tumor Microenvironment ◽  
Patient Outcomes ◽  
Cytotoxic T Lymphocyte ◽  
Cell Types ◽  
Development Of Resistance ◽  
Improve Patient Selection ◽  
Potential Biomarker ◽  
Programmed Cell Death 1 ◽  
Tumor Biopsies

Immunotherapies blocking immune inhibitory receptors programmed cell death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) on T-cells have dramatically improved patient outcomes in a range of advanced cancers. However, the lack of response, and the development of resistance remain major obstacles to long-term improvements in patient outcomes. There is significant interest in the clinical use of biomarkers to improve patient selection, and the expression of PD-1 ligand 1 (PD-L1) is often reported as a potential biomarker of response. However, accumulating evidence suggests that the predictive value of PD-L1 expression in tumor biopsies is relatively low due, in part, to its complex biology. In this review, we discuss the biological consequences of PD-L1 expression by various cell types within the tumor microenvironment, and the complex mechanisms that regulate PD-L1 expression at the genomic, transcriptomic and proteomic levels.

Interphase phosphorylation of the Drosophila nuclear lamin: site-mapping using a monoclonal antibody

1995 ◽  
Vol 108 (9) ◽  
pp. 3137-3144 ◽  
Author(s):  
N. Stuurman ◽  
N. Maus ◽  
P.A. Fisher
Keyword(s):  
Monoclonal Antibody ◽  
Polyacrylamide Gel Electrophoresis ◽  
Phosphorylation Site ◽  
Cell Types ◽  
Drosophila Cell ◽  
Nuclear Lamins ◽  
Site Mapping ◽  
Nuclear Lamin ◽  
Phosphatase Treatment ◽  
Polymerase Chain

The Drosophila nuclear lamin is highly phosphorylated during interphase. Two interphase isoforms, differing in degree of phosphorylation, can be distinguished by one-dimensional SDS-polyacrylamide gel electrophoresis. One migrates with an apparent mass of 74 kDa (lamin Dm1); the other is more highly phosphorylated and migrates as a 76 kDa protein (lamin Dm2). We generated a monoclonal antibody, ADL84 which binds to lamin Dm1 but not lamin Dm2. Binding of ADL84 to lamin Dm2 was restored by phosphatase treatment of immunoblots containing lamins. Immunoprecipitation with ADL84 demonstrated that purified Drosophila nuclear lamins Dm1 and Dm2 are present as a random mixture of homo- and heterodimers. Indirect immunofluorescence experiments suggest that lamin Dm1 is present in all Drosophila cell types. The epitope for ADL84 was mapped by analyzing binding to bacterially expressed lamin deletion mutants and subsequently by screening for point mutants (randomly generated by polymerase chain reaction) which were not recognized by ADL84. The ADL84-epitope encompasses amino acids R22PPSAGP (arginine 22-proline 28). Peptide competition experiments demonstrated directly that phosphorylation of serine 25 impedes lamin binding by ADL84. This suggests that serine 25 is the lamin Dm2-specific phosphorylation site.

Mechanisms, Applications, and Challenges of Insect RNA Interference

2020 ◽  
Vol 65 (1) ◽  
pp. 293-311 ◽  
Author(s):  
Kun Yan Zhu ◽  
Subba Reddy Palli
Keyword(s):  
Rna Interference ◽  
Pest Management ◽  
New Technologies ◽  
Insect Pest ◽  
Management Strategies ◽  
Cationic Liposome ◽  
Delivery Methods ◽  
Nontarget Effects ◽  
Development Of Resistance ◽  
Rnai Efficiency

The RNA interference (RNAi) triggered by short/small interfering RNA (siRNA) was discovered in nematodes and found to function in most living organisms. RNAi has been widely used as a research tool to study gene functions and has shown great potential for the development of novel pest management strategies. RNAi is highly efficient and systemic in coleopterans but highly variable or inefficient in many other insects. Differences in double-stranded RNA (dsRNA) degradation, cellular uptake, inter- and intracellular transports, processing of dsRNA to siRNA, and RNA-induced silencing complex formation influence RNAi efficiency. The basic dsRNA delivery methods include microinjection, feeding, and soaking. To improve dsRNA delivery, various new technologies, including cationic liposome–assisted, nanoparticle-enabled, symbiont-mediated, and plant-mediated deliveries, have been developed. Major challenges to widespread use of RNAi in insect pest management include variable RNAi efficiency among insects, lack of reliable dsRNA delivery methods, off-target and nontarget effects, and potential development of resistance in insect populations.

scholarly journals Novel tool to quantify cell wall porosity relates wall structure to cell growth and drug uptake

2019 ◽  
Vol 218 (4) ◽  
pp. 1408-1421 ◽  
Author(s):  
Xiaohui Liu ◽  
Jiazhou Li ◽  
Heyu Zhao ◽  
Boyang Liu ◽  
Thomas Günther-Pomorski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Dynamic Structure ◽  
Cell Types ◽  
Antifungal Drugs ◽  
Drug Uptake ◽  
Wall Structure ◽  
Quenching Efficiency ◽  
Model Plant Arabidopsis Thaliana ◽  
Cell Wall Porosity

Even though cell walls have essential functions for bacteria, fungi, and plants, tools to investigate their dynamic structure in living cells have been missing. Here, it is shown that changes in the intensity of the plasma membrane dye FM4-64 in response to extracellular quenchers depend on the nano-scale porosity of cell walls. The correlation of quenching efficiency and cell wall porosity is supported by tests on various cell types, application of differently sized quenchers, and comparison of results with confocal, electron, and atomic force microscopy images. The quenching assay was used to investigate how changes in cell wall porosity affect the capability for extension growth in the model plant Arabidopsis thaliana. Results suggest that increased porosity is not a precondition but a result of cell extension, thereby providing new insight on the mechanism plant organ growth. Furthermore, it was shown that higher cell wall porosity can facilitate the action of antifungal drugs in Saccharomyces cerevisiae, presumably by facilitating uptake.

Prostaglandin transporter PGT is expressed in cell types that synthesize and release prostanoids

2002 ◽  
Vol 282 (6) ◽  
pp. F1103-F1110 ◽  
Author(s):  
Yi Bao ◽  
Michael L. Pucci ◽  
Brenda S. Chan ◽  
Run Lu ◽  
Shigekazu Ito ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Mesangial Cells ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Cell Types ◽  
Proximal Tubules ◽  
Surface Epithelium ◽  
Extracellular Loop ◽  
Insight Into ◽  
Rat Platelets

PGT is a broadly expressed transporter of prostaglandins (PGs) and thromboxane that is energetically poised to take up prostanoids across the plasma membrane. To gain insight into the function of PGT, we generated mouse monoclonal antibody 20 against a portion of putative extracellular loop 5 of rat PGT. Immunoblots of endogenous PGT in rat kidney revealed a 65-kDa protein in a zonal pattern corresponding to PG synthesis rates (papilla ≅ medulla > cortex). Immunocytochemically, PGT in rat kidneys was expressed in glomerular endothelial and mesangial cells, arteriolar endothelial and muscularis cells, principal cells of the collecting duct, medullary interstitial cells, medullary vasa rectae endothelia, and papillary surface epithelium. Proximal tubules, which are known to take up and metabolize PGs, were negative. Immunoblotting and immunocytochemistry revealed that rat platelets also express abundant PGT. Coexpression of the PG synthesis apparatus (cyclooxygenase) and PGT by the same cell suggests that prostanoids may undergo release and reuptake.

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