MECHANICS OF PARENCHYMA TISSUE BASED ON CELL ORIENTATION AND MICROSTRUCTURE

1991 ◽  
Vol 34 (1) ◽  
pp. 0232 ◽  
Author(s):  
Q. Gao ◽  
R. E. Pitt
Keyword(s):  
Cell Orientation ◽  
Parenchyma Tissue

Cell orientation in potato tuber parenchyma tissue

2014 ◽  
Vol 28 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Marek Gancarz ◽  
Krystyna Konstankiewicz ◽  
Kazimiera Zgórska
Keyword(s):  
Inner Core ◽  
Longitudinal Direction ◽  
Outer Core ◽  
Surface Shape ◽  
Natural State ◽  
Cell Orientation ◽  
Size And Shape ◽  
Kolmogorov Smirnov ◽  
Number Of Cells ◽  
Parenchyma Tissue

Abstract The paper presents the results of the research of the size and shape of parenchyma tissue cells in potato tubers depending on the direction and site of sampling in tubers. An optical confocal microscope was used to observe samples in their natural state. The investigation was carried out for 1 mm thick samples cut from cylindrical samples (10x10 mm)taken in two mutually perpendicular directions of the inner and outer core of each variety. The analysis was done ten times.The methods developed for the composition and image analysis ensure obtaining a sufficient number of cells to determine tissue structure parameters (surface, shape, elongation and number of cells per 1 mm2) and decays of these parameters were obtained. Statistical analysis was performed using the λ-Kolmogorov-Smirnov compliance test.Arelationship between the direction of sampling and the size and shape of the inner core of cells was found. Greater surface area and elongation of the inner core cells for the longitudinal direction in the tuber (stolon - top) was demonstrated. There was no such a correlation for the outer core in the tubers of the cultivars examined.

scholarly journals Kindlin-2 mediates mechanotransduction in bone by regulating expression of Sclerostin in osteocytes

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Lei Qin ◽  
Xuekun Fu ◽  
Jing Ma ◽  
Manxia Lin ◽  
Peijun Zhang ◽  
...  
Keyword(s):  
Bone Loss ◽  
Mechanical Stimulation ◽  
Fluid Shear Stress ◽  
Weight Bearing ◽  
Underlying Mechanism ◽  
Long Bones ◽  
Cell Orientation ◽  
Cytoskeleton Organization

AbstractOsteocytes act as mechanosensors in bone; however, the underlying mechanism remains poorly understood. Here we report that deleting Kindlin-2 in osteocytes causes severe osteopenia and mechanical property defects in weight-bearing long bones, but not in non-weight-bearing calvariae. Kindlin-2 loss in osteocytes impairs skeletal responses to mechanical stimulation in long bones. Control and cKO mice display similar bone loss induced by unloading. However, unlike control mice, cKO mice fail to restore lost bone after reloading. Osteocyte Kindlin-2 deletion impairs focal adhesion (FA) formation, cytoskeleton organization and cell orientation in vitro and in bone. Fluid shear stress dose-dependently increases Kindlin-2 expression and decreases that of Sclerostin by downregulating Smad2/3 in osteocytes; this latter response is abolished by Kindlin-2 ablation. Kindlin-2-deficient osteocytes express abundant Sclerostin, contributing to bone loss in cKO mice. Collectively, we demonstrate an indispensable novel role of Kindlin-2 in maintaining skeletal responses to mechanical stimulation by inhibiting Sclerostin expression during osteocyte mechanotransduction.

Effects of potassium deficiency and simulated acid rain, alone and in combination, on the ultrastructure of Scots pine needles

1989 ◽  
Vol 19 (11) ◽  
pp. 1402-1411 ◽  
Author(s):  
Toini Holopainen ◽  
Pekka Nygren
Keyword(s):  
Acid Rain ◽  
Scots Pine ◽  
Potassium Deficiency ◽  
Simulated Acid Rain ◽  
Sand Culture ◽  
Short Term ◽  
Transmission Electron ◽  
Resting Period ◽  
Lipid Structures ◽  
Parenchyma Tissue

The effects of potassium deficiency and artificial acid precipitation, alone and in combination, on Scots pine (Pinussilvestris L.) needles were studied using transmission electron microscopy. The seedling material was grown in quartz sand culture and watered with nutrient solution containing 45, 20, 10, or 5 mg of potassium/L; the concentration of other nutrients was constant and equally available for all seedlings. A portion of the seedlings from each group received consecutive acidified water spraying of pH 4.5, 4.0, 3.5, and 3.0, each for 4 days with a 3-day resting period between applications. The potassium deficiency caused an increase in the proportional vacuolar space and severe vesiculation of the tonoplast. Irregularly shaped lipid structures increased in number in the cytoplasm, and lipid bodies also appeared in the vacuoles and occasionally in the chloroplasts. The symptoms related to potassium deficiency were more severe in the transfusion parenchyma cells than in the mesophyll. The lowest level of potassium produced almost complete disorganization of the cellular structures in the transfusion parenchyma tissue, but severe changes were also seen in the mesophyll. The simulated acid rain treatment caused the formation of protrusions in the chloroplasts and an increase in irregularly shaped lipid structures in the cytoplasm throughout the mesophyll tissue, but no clear symptoms were observed inside the bundle sheath. In general, the changes caused by acid rain in the chloroplasts were slight and did not cause serious disorganization of these organelles. When the seedlings were exposed to combination treatment, the typical symptoms of both exposures were observable. The results suggest that the stresses caused by potassium deficiency and short-term foliar acid rain treatment can be distinguished in the needle ultrastructure.

Micropatterned Cell Orientation of Cyanobacterial Liquid-Crystalline Hydrogels

2018 ◽  
Vol 10 (51) ◽  
pp. 44834-44843 ◽  
Author(s):  
Saranyoo Sornkamnerd ◽  
Maiko K. Okajima ◽  
Kazuaki Matsumura ◽  
Tatsuo Kaneko
Keyword(s):  
Liquid Crystalline ◽  
Cell Orientation

Z-Axis Calibration in Optical Sectioning from Xylem Cross Sections for Grain Angle Measurement

IAWA Journal ◽  
2005 ◽  
Vol 26 (4) ◽  
pp. 427-441 ◽  
Author(s):  
Yoshiyuki Ogata ◽  
Minoru Fujita
Keyword(s):  
Cell Wall ◽  
Confocal Microscopy ◽  
Present Report ◽  
Orientation Angle ◽  
Sample Surface ◽  
Angle Measurement ◽  
Cell Orientation ◽  
Optical Sectioning ◽  
Grain Angle ◽  
Cross Correlation Analysis

Optical sectioning using confocal microscopy may be problematic under some conditions due to contamination with light from outside the focal plane and resulting z-axis compression. These problems can affect quantitative wood anatomy, such as grain angle measurement. In the present report, the exact surface of xylem sections, z-axis scaling, and available scanning depth with confocal microscopy were determined in xylem transverse sections of Japanese cedar (Cryptomeria japonica D. Don). The optical section containing the sample surface was determined using power spectral analysis to find the sharpest image. Image cross-correlation analysis in serial transverse optical sections revealed that the optical sections above the sample surface showed no tangential shift with that of the surface, indicating the non-focal cell wall information. Optical sections using an oil immersion lens with oil and a dry lens without oil were compared. Optical sections with an oil lens were relatively precise while those with a dry lens showed a z-axis distortion of about ×1.5 due to the mismatch of refractive index. Therefore, the exact cell orientation angle without oil can be obtained by the two-thirds multiplication. Adequate cell wall information was available up to c. 80 μm deep.

Involvement of SA channels in orienting response of cultured endothelial cells to cyclic stretch

1998 ◽  
Vol 274 (5) ◽  
pp. H1532-H1538 ◽  
Author(s):  
Keiji Naruse ◽  
Takako Yamada ◽  
Masahiro Sokabe
Keyword(s):  
Endothelial Cells ◽  
Cell Elongation ◽  
Umbilical Vein ◽  
Orienting Response ◽  
Cyclic Stretch ◽  
Silicone Membrane ◽  
Cell Orientation ◽  
Human Umbilical Vein ◽  
Intracellular Ca ◽  
Dependent Cell

The present work was designed to elucidate the involvement of Ca2+-permeable stretch-activated (SA) channels in the orienting response of endothelial cells to uniaxial cyclic stretch. Endothelial cells from human umbilical vein were cultured on an elastic silicone membrane and subjected to uniaxial cyclic stretch (120% in length, 1 Hz). The cells started to change their morphology 15 min after the onset of stretch, and >90% of the cells oriented perpendicularly to the stretch axis after 2 h. Associated with the orienting response, cell elongation proceeded with a slower rate. Both of the orientating and elongating responses were largely inhibited by the removal of external Ca2+ or by Gd3+, a potent blocker for the SA channel, but not by nifedipine. Intracellular Ca2+ concentration ([Ca2+]i) transiently increased in response to uniaxial stretch, and the basal [Ca2+]igradually increased during cyclic stretch. This Ca2+ response was inhibited by the removal of extracellular Ca2+ or by the addition of Gd3+. These results suggest that stretch-dependent Ca2+ influx through SA channels is essential in the stretch-dependent cell orientation and elongation.

The effects of disorientation on visual landmark control of head direction cell orientation

1997 ◽  
Vol 115 (2) ◽  
pp. 375-380 ◽  
Author(s):  
P. A. Dudchenko ◽  
Jeremy P. Goodridge ◽  
J. S. Taube
Keyword(s):  
Head Direction ◽  
Cell Orientation ◽  
Visual Landmark ◽  
Head Direction Cell
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