scholarly journals Effect of Exogenously Applied 24-Epibrassinolide and Brassinazole on Xylogenesis and Microdistribution of Cell Wall Polymers in Leucaena leucocephala (Lam) De Wit

2021 ◽  
Author(s):  
S. Pramod ◽  
M. Anju ◽  
H. Rajesh ◽  
A. Thulaseedharan ◽  
Karumanchi S. Rao
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Leucaena Leucocephala ◽  
Higher Plants ◽  
Lignin Content ◽  
Wood Quality ◽  
Wall Structure ◽  
Vessel Element ◽  
Xylem Differentiation ◽  
Cell Wall Polymers

AbstractPlant growth regulators play a key role in cell wall structure and chemistry of woody plants. Understanding of these regulatory signals is important in advanced research on wood quality improvement in trees. The present study is aimed to investigate the influence of exogenous application of 24-epibrassinolide (EBR) and brassinosteroid inhibitor, brassinazole (BRZ) on wood formation and spatial distribution of cell wall polymers in the xylem tissue of Leucaena leucocephala using light and immuno electron microscopy methods. Brassinazole caused a decrease in cambial activity, xylem differentiation, length and width of fibres, vessel element width and radial extent of xylem suggesting brassinosteroid inhibition has a concomitant impact on cell elongation, expansion and secondary wall deposition. Histochemical studies of 24-epibrassinolide treated plants showed an increase in syringyl lignin content in the xylem cell walls. Fluorescence microscopy and transmission electron microscopy studies revealed the inhomogenous pattern of lignin distribution in the cell corners and middle lamellae region of BRZ treated plants. Immunolocalization studies using LM10 and LM 11 antibodies have shown a drastic change in the micro-distribution pattern of less substituted and highly substituted xylans in the xylem fibres of plants treated with EBR and BRZ. In conclusion, present study demonstrates an important role of brassinosteroid in plant development through regulating xylogenesis and cell wall chemistry in higher plants.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

scholarly journals Susceptibility Pattern of Caspofungin-Coated Gold Nanoparticles against Clinically Important Candida Species

2020 ◽  
Author(s):  
Zahra Salehi ◽  
Azam Fattahi ◽  
Ensieh lotfali ◽  
Abdolhassan Kazemi ◽  
Ali Shakeri-Zadeh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Cell Wall ◽  
Candida Species ◽  
Spherical Shape ◽  
Sem Analysis ◽  
Antifungal Drugs ◽  
Wall Structure ◽  
Candida Spp ◽  
Average Size

Purpose: The present study was performed to examine whether caspofungin-coated gold nanoparticles (CAS-AuNPs) may offer the right platform for sensitivity induction in resistant isolates. Methods: For the purpose of the study, a total of 58 archived Candida species were enrolled in the research. The identification of Candida spp. was performed using polymerase chain reaction-restriction fragment length polymorphism and HWP1 gene amplification approaches. The conjugated CAS-AuNPs were synthesized and then characterized using transmission electron microscopy (TEM) and Zetasizer system to determine their morphology, size, and charge. Furthermore, the efficacy of CAS, CAS-AuNPs conjugate, and AuNPs against Candida spp. was assessed based on the Clinical and Laboratory Standards Institute M60. Finally, the interaction of CAS-AuNPs with Candida element was evaluated via scanning electron microscopy (SEM). Results: According to the TEM results, the synthesized CAS-AuNPs had a spherical shape with an average size of 20 nm. The Zeta potential of CAS-AuNPs was -38.2 mV. Statistical analyses showed that CAS-AuNPs could significantly reduce the minimum inhibitory concentration against C. albicans (P=0.0005) and non-albicans Candida (NAC) species (P<0.0001). All isolates had a MIC value of ≥ 4 µg/ml for CAS, except for C. glabrata. The results of SEM analysis confirmed the effects of AuNPs on the membrane and cell wall structure of C. globrata exposed to CAS-AuNPs, facilitating the formation of pores on the cell wall and finally cell death. Conclusion: The findings revealed that CAS-AuNPs conjugates had significant antifungal effects against Candida spp. through the degradation of the membrane and cell wall integrity. Therefore, it can be concluded that the encapsulation of antifungal drugs in combination with NPs not only diminishes side effects but also enhances the effectiveness of the medications.

scholarly journals Chemical composition, anatomy, lignin distribution, and cell wall structure of Malaysian plant waste fibers

BioResources ◽  
2006 ◽  
Vol 1 (2) ◽  
pp. 220-232 ◽  
Author(s):  
H. P. S. Abdul Khalil ◽  
M. Siti Alwani ◽  
A. K. Mohd Omar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Chemical Composition ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Anatomical Characteristics ◽  
Lignin Distribution ◽  
Transmission Electron ◽  
Palm Frond

The chemical composition, anatomical characteristics, lignin distribution, and cell wall structure of oil palm frond (OPF), coconut (COIR), pine-apple leaf (PALF), and banana stem (BS) fibers were analyzed. The chemical composition of fiber was analyzed according to TAPPI Methods. Light microscopy (LM) and transmission electron microscopy (TEM) were used to observe and determine the cell wall structure and lignin distribution of various agro-waste fibers. The results revealed differences in anatomical characteristics, lignin distributions, and cell wall structure of the different types of fibers investigated. Nevertheless, transmission electron microscopy (TEM) micrographs have confirmed that the well wall structure, in each case, could be described in terms of a classical cell wall structure, consisting of primary (P) and secondary (S 1 , S 2 , and S 3 ) layers.

Sugarcane cell wall structure and lignin distribution investigated by confocal and electron microscopy

2013 ◽  
Vol 76 (8) ◽  
pp. 829-834 ◽  
Author(s):  
Celso Sant'Anna ◽  
Lilian T. Costa ◽  
Yuri Abud ◽  
Lucas Biancatto ◽  
Flávio Costa Miguens ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Lignin Distribution ◽  
Confocal And Electron Microscopy

scholarly journals Structural colour from helicoidal cell-wall architecture in fruits of Margaritaria nobilis

2016 ◽  
Vol 13 (124) ◽  
pp. 20160645 ◽  
Author(s):  
Silvia Vignolini ◽  
Thomas Gregory ◽  
Mathias Kolle ◽  
Alfie Lethbridge ◽  
Edwige Moyroud ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Optical Measurements ◽  
Wall Structure ◽  
Single Cell Level ◽  
Cell Level ◽  
Circularly Polarized ◽  
Transmission Electron ◽  
Green Coloration ◽  
Cell Wall Architecture

The bright and intense blue-green coloration of the fruits of Margaritaria nobilis (Phyllanthaceae) was investigated using polarization-resolved spectroscopy and transmission electron microscopy. Optical measurements of freshly collected fruits revealed a strong circularly polarized reflection of the fruit that originates from a cellulose helicoidal cell wall structure in the pericarp cells. Hyperspectral microscopy was used to capture the iridescent effect at the single-cell level.

Molecular xylem cell wall structure of an inclined Cycas micronesica stem, a tropical gymnosperm

IAWA Journal ◽  
2010 ◽  
Vol 31 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Clemens M. Altaner ◽  
Michael C. Jarvis ◽  
Jack B. Fisher ◽  
Thomas E. Marler
Keyword(s):  
Cell Wall ◽  
Compression Wood ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Picea Sitchensis ◽  
Wall Structure ◽  
Crystalline Cellulose ◽  
Cellulose Structure ◽  
Molecular Features ◽  
Cellulose Fibrils

The molecular structure of tracheid walls of an inclined eccentrically grown stem of Cycas micronesica K.D. Hill did not differ between the upper and lower side. The absence the typical molecular features of compression wood tracheids, i.e. an increased galactose and lignin content as well as an increased microfibril angle, indicated that cycads do not have the ability to form even very mild forms of compression wood, which lacks anatomical features commonly observed in compression wood. Analysis of the sugar monomers in Cycas micronesica tracheids did reveal a rather unique composition of the non-cellulosic polysaccharides for a gymnosperm. The low mannose and high xylose content resembled a cell wall matrix common in angiosperms. The crystalline cellulose structure in Cycas micronesica tracheids closely resembled those of secondary cell walls in Picea sitchensis (Bong.) Carr. tracheids. However, the spacing between the sheets of cellulose chains was wider and the cellulose fibrils appeared to form larger aggregates than in Sitka spruce tracheids.

Cytological comparison of early stages of wall regeneration of Cercospora nicotianae and Neurospora crassa protoplasts

1989 ◽  
Vol 67 (7) ◽  
pp. 1938-1943 ◽  
Author(s):  
Kimberly D. Gwinn ◽  
Margaret E. Daub ◽  
Pi-Yu Huang
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Neurospora Crassa ◽  
Protoplast Isolation ◽  
Differential Sensitivity ◽  
Wall Material ◽  
Wall Structure ◽  
Cell Wall Material ◽  
Isolated Protoplasts ◽  
Regeneration Period

Freshly isolated protoplasts of Cercospora nicotianae and Neurospora crassa are equally sensitive to the toxin, cercosporin. After a 12-h regeneration period C. nicotianae cells are resistant, but N. crassa cells remain sensitive. Production of cell wall material by both C. nicotianae and N. crassa was monitored by transmission electron microscopy and fluorescence microscopy. Freshly isolated protoplasts lacked cell wall material as shown by observation with electron microscopy and inability to bind the fluorescent brightener Tinopal 5BM. After a 12-h incubation, electron micrographs of regenerating protoplasts showed well-developed cell walls for N. crassa, whereas C. nicotianae displayed variations in wall structure. Ability to bind Tinopal 5BM was acquired very early by regenerating cells of both fungi. Percentages of cells that could bind Concanavalin A did not differ between the two fungi at any time after protoplast isolation. Ability to bind wheat germ agglutinin and Bandeiraea simplicifolia agglutinin II was detected earlier in C. nicotianae than in N. crassa. These data demonstrate the presence of cell wall materials in both C. nicotianae and N. crassa at the time that differential sensitivity to cercosporin is observed. These results suggest that components in the C. nicotianae cell wall may play a role in cercosporin resistance.

scholarly journals Identifying transcription factors that reduce wood recalcitrance and improve enzymatic degradation of xylem cell wall in Populus

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chiaki Hori ◽  
Naoki Takata ◽  
Pui Ying Lam ◽  
Yuki Tobimatsu ◽  
Soichiro Nagano ◽  
...  
Keyword(s):  
Cell Wall ◽  
Populus Tremuloides ◽  
Cell Walls ◽  
Enzymatic Degradation ◽  
Plant Biomass ◽  
Lignin Content ◽  
Enzymatic Saccharification ◽  
Wall Structure ◽  
Xylem Cell

AbstractDeveloping an efficient deconstruction step of woody biomass for biorefinery has been drawing considerable attention since its xylem cell walls display highly recalcitrance nature. Here, we explored transcriptional factors (TFs) that reduce wood recalcitrance and improve saccharification efficiency in Populus species. First, 33 TF genes up-regulated during poplar wood formation were selected as potential regulators of xylem cell wall structure. The transgenic hybrid aspens (Populus tremula × Populus tremuloides) overexpressing each selected TF gene were screened for in vitro enzymatic saccharification. Of these, four transgenic seedlings overexpressing previously uncharacterized TF genes increased total glucan hydrolysis on average compared to control. The best performing lines overexpressing Pt × tERF123 and Pt × tZHD14 were further grown to form mature xylem in the greenhouse. Notably, the xylem cell walls exhibited significantly increased total xylan hydrolysis as well as initial hydrolysis rates of glucan. The increased saccharification of Pt × tERF123-overexpressing lines could reflect the improved balance of cell wall components, i.e., high cellulose and low xylan and lignin content, which could be caused by upregulation of cellulose synthase genes upon the expression of Pt × tERF123. Overall, we successfully identified Pt × tERF123 and Pt × tZHD14 as effective targets for reducing cell wall recalcitrance and improving the enzymatic degradation of woody plant biomass.

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