scholarly journals Ultrastructural Changes in Chloroplasts in Harvested Broccoli Flower Buds During Senescence

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 824C-824
Author(s):  
Hirofumi Terai ◽  
Hironobu Tsuchida ◽  
Masashi Mizuno ◽  
Yumi Fukui
Keyword(s):  
Structural Changes ◽  
Optical Microscope ◽  
Ultrastructural Changes ◽  
Scanning Electron Micrographs ◽  
Small Particles ◽  
Flower Buds ◽  
Electron Microscopic ◽  
Green Color ◽  
Polyethylene Bags ◽  
Scanning Electron

Green broccoli (Brassica oleracea L. Italica Group) flower heads were stored in perforated polyethylene bags at 20C. Green color of sepals in broccoli flower buds changed to yellow and individual flower buds wilted gradually during storage. Chlorophyllase activity in flower buds tended to increase and chlorophyll content decreased during senescence. Optical and scanning electron microscopic observations were conducted to elucidate the structural changes of chloroplasts in sepals of broccoli flower buds through the senescence. The chloroplasts observed with optical microscope were fine and green when the stage of broccoli flower buds was all green. However, at half-yellow stage, the shapes of chloroplasts obscured and the green color faded. After this stage, colored small particles appeared in the cells and the number of particles tended to increase as yellowing of the flower buds progressed through the senescence. Scanning electron micrographs indicated that the small particles were formed in the chloroplasts and come out from them with senescence followed by aggregation with each other.

Ultrastructural Changes in Euglena After Ultraviolet Irradiation

1973 ◽  
Vol 13 (3) ◽  
pp. 799-809
Author(s):  
A. MICHAELS ◽  
A. GIBOR
Keyword(s):  
Ultraviolet Light ◽  
Ultraviolet Irradiation ◽  
Euglena Gracilis ◽  
Structural Changes ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Bleaching Process ◽  
In Cells

The structural changes associated with the ultraviolet-induced bleaching of light-grown cells of Euglena gracilis were investigated. Our light- and electron-microscopic observations of the bleaching process indicate that there is a continuity of plastid structure in cells 5 generations after receiving a bleaching dose of ultraviolet light. There seems to be a continuous dilution of the plastid thylakoids and a decrease in plastid size in the bleaching cells. There also seems to be a change in the position of the plastids in relation to the mitochondria in the bleaching cells. The plastids and possibly the mitochondria are the only organelles which are affected by the ultraviolet irradiation. The continuity of plastids in bleaching cells of Euglena is discussed in relation to the proposed effect of the ultraviolet light.

scholarly journals Beneficial effect of genistein on lowering blood pressure and kidney toxicity in fructose-fed hypertensive rats

2012 ◽  
Vol 109 (10) ◽  
pp. 1806-1812 ◽  
Author(s):  
Nallasamy Palanisamy ◽  
Anuradha C. Venkataraman
Keyword(s):  
Blood Pressure ◽  
Structural Changes ◽  
Ultrastructural Changes ◽  
Hypertensive Rats ◽  
Enos Expression ◽  
Electron Microscopic ◽  
Plasma Angiotensin ◽  
Enhanced Expression ◽  
Male Wistar Rats ◽  
Microscopic Studies

The study evaluates the effects of genistein on blood pressure (BP) and ultrastructural changes in kidney of fructose-fed hypertensive rats. Male Wistar rats were fed a diet containing 60 % starch or 60 % fructose as the source of carbohydrate. After 15 d, rats in each dietary group were divided into two groups and were treated with either genistein (1 mg/kg per d) in dimethylsulfoxide (DMSO) or 30 % DMSO alone. BP, pressor mechanisms, protein kinase C-βII (PKC-βII) expression, endothelial NO synthase (eNOS) expression and renal ultrastructural changes were evaluated after 60 d. Fructose-fed rats displayed significant elevation in BP and heart rate. Significant increase in plasma angiotensin-converting enzyme (ACE) activity, alterations in renal lipid profile, nitrite and kallikrein activity, enhanced expression of membrane-associated PKC-βII and decreased expression of eNOS were observed in them. Histology and electron microscopic studies showed structural changes in the kidney. Genistein administration lowered BP, restored ACE, PKC-βII and eNOS expression and preserved renal ultrastructural integrity. These findings demonstrate that genistein has effects on eNOS activity in renal cells, leading to eNOS activation and NO synthesis. These effects could have been mediated by activation of PKC-βII. The observed benefits of genistein make it a promising candidate for therapy of diabetic kidney disease.

scholarly journals The Morphological Assessment of Rats` Liver after the Introduction of the Nucleoside Reverse Transcriptase Inhibitor of Azidothymidine

2019 ◽  
pp. 61-67
Author(s):  
M. N. Kurbat ◽  
R. I. Kravchuk ◽  
O. B. Ostrovskaya
Keyword(s):  
Nucleoside Reverse Transcriptase Inhibitor ◽  
Structural Changes ◽  
Electron Microscopic Examination ◽  
Transcriptase Inhibitor ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Structural And Functional Properties ◽  
Hepatotoxic Effect ◽  
Reverse Transcriptase Inhibitor ◽  
Morphological Assessment

Objective: to study the microscopic and ultrastructural changes in the liver of rats exposed to AZT. Material and methods. The histological and electron microscopic examination of the liver samples with mitochondrial morphometry has been performed. Results . The 7-day administration of AZT does not cause any significant structural changes in the liver. The exposure to the drug for 21 days leads to the development of moderate inflammatory and degenerative processes in the liver, including changes in the structure of hepatocyte mitochondria. Conclusion. One of the pathogenetic mechanisms of the hepatotoxic effect of AZT is its impact on the structural and functional properties of hepatocyte mitochondria.

scholarly journals Scanning Electron Microscopic Study of Modified Chloroplasts in Senescing Broccoli Florets

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Hirofumi Terai ◽  
Alley E. Watada ◽  
Charles A. Murphy ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Structural changes in chloroplasts of broccoli (Brassica oleracea L., Italica group) florets during senescence were examined using light microscopy, scanning electron microscopy (SEM) with freeze-fracture technique, and transmission electron microscopy (TEM) to better understand the process of chloroplast degradation, particularly at the advanced stage of senescence. Light microscopy revealed that chloroplasts, which initially were intact and green, became obscure in shape, and their color faded during senescence. Small, colored particles appeared in cells as the florets approached the final stage of senescence and became full- to dark-yellow in color. Scanning electron microscopy showed that stroma thylakoids in the chloroplast initially were parallel to each other and grana thylakoids were tightly stacked. As senescence advanced, the grana thylakoids degenerated and formed globules. The globules became larger by aggregation as senescence progressed, and the large globules, called “thylakoid plexus,” formed numerous vesicles. The vesicles ultimately were expelled into the cytosol, and the light microscope revealed many colored particles in the senescent cells. These results indicate that the degradation of chloroplasts in broccoli florets progresses systematically, with the final product being colored particles, which are visible in yellow broccoli sepal cells.

scholarly journals Effectiveness of a Canal Brush on Removing Smear Layer: A Scanning Electron Microscopic Study

2013 ◽  
Vol 24 (6) ◽  
pp. 580-584 ◽  
Author(s):  
Eleni Protogerou ◽  
Ioanna Arvaniti ◽  
Ioannis Vlachos ◽  
Marouan Georgios Khabbaz
Keyword(s):  
Statistical Difference ◽  
Optical Microscope ◽  
Smear Layer ◽  
Electron Microscopic ◽  
Root Canals ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Group A ◽  
Group B ◽  
Scanning Electron

This study evaluated the effectiveness of a highly flexible endodontic brush made of polypropylene canal brush (CanalBrush; Coltène) on smear layer removal from the canal walls when used according to the manufacturer's recommendations. Forty-four single-rooted mandibular incisors were prepared to apical size 30/0.06 and randomly divided into three groups A, B and C, where the final irrigation regimen was 10 mL 17% EDTA and 10 mL 2.5% NaOCl for group A, 10 mL EDTA, 5 mL NaOCl, CanalBrush for 20 s at 450 rpm and 5 mL NaOCl for group B, 10 mL NaOCl, CanalBrush and 10 mL NaOCl for group C. One medium-sized CanalBrush was used for each root canal and all brushes were examined under the optical microscope after application to evaluate bristle deformation. Afterwards, roots were split longitudinally and the presence of smear layer was evaluated under a scanning electron microscope. Used brushes invariably exhibited bristle deformation. Group C exhibited the highest means of smear layer in all thirds. Comparing the apical thirds in all groups, there was no statistical difference between groups A and B (3.64±0.48 and 3.68±0.62 respectively), while group C exhibited significantly higher scores (3.9±0.28) than the other two groups. In conclusion, the CanalBrush proved unable to remove smear layer from the instrumented root canals, when used according to the manufacturers' instructions.

In-situ Tensile Straining of Metal Films on Polymer Substrates under an AFM

2013 ◽  
Vol 1527 ◽  
Author(s):  
M.J. Cordill ◽  
V.M. Marx
Keyword(s):  
Optical Microscope ◽  
Metal Films ◽  
Scanning Electron Micrographs ◽  
Adhesion Properties ◽  
Polymer Substrates ◽  
Fragmentation Test ◽  
First Occurrence ◽  
Film Substrate ◽  
Scanning Electron

ABSTRACTMetal films on polymer substrates are commonly used in flexible electronic devices and as gas barrier coatings. One way to evaluate the fracture and adhesion properties of such film systems is the fragmentation test. In the fragmentation test a film-substrate system is strained in tension under an optical microscope or inside a scanning electron microscope to observe the cracking and delamination events in situ. The technique works very well for brittle metal and ceramic films. However, when ductile films are strained they deform plastically before cracks and buckles appear. Therefore, a tensile straining device was developed to fit under an AFM for in situ observation of ductile metal films on polymer substrates. With the new in situ device the first occurrence of plastic deformation in the form of localized thinning of the film and channel cracks are visible. These features can only be detected through a height difference in the AFM images and not with optical or scanning electron micrographs. A comparison to brittle Cr films on polymer substrates was performed.

scholarly journals Testate Amoebae (Amebozoa: Arcellinida) in Tropical Lakes of Central Mexico

2016 ◽  
Vol 64 (1) ◽  
pp. 377 ◽  
Author(s):  
Itzel Sigala ◽  
Socorro Lozano-García ◽  
Jaime Escobar ◽  
Liseth Pérez ◽  
Elvia Gallegos-Neyra
Keyword(s):  
Volcanic Belt ◽  
Distribution Patterns ◽  
Testate Amoebae ◽  
Optical Microscope ◽  
Tropical Lakes ◽  
Scanning Electron Micrographs ◽  
Taxonomic Richness ◽  
Aperture Diameter ◽  
Eukaryotic Organisms ◽  
Scanning Electron

Testate amoebae are common single-celled eukaryotic organisms in aquatic ecosystems. Despite their important role in these ecosystems, and their potential as bioindicators and paleoindicators, they remain poorly studied in Mexico. The major objectives of this study were to: 1) increase knowledge of testate amoebae in Mexico’s tropical lakes, and 2) create a catalog of high-quality scanning electron micrographs that can be used for future ecological and paleoenvironmental studies. We collected surface-sediment samples from 29 lakes, located in the Transmexican Volcanic Belt, one at each lake during June and October 2011, and March 2013. Sediments were collected with an Ekman grab and preserved in anhydrous ethanol. Sub-samples were observed under a stereomicroscope and morphometric data for each species were recorded. Total diameter and aperture diameter were measured on circular tests. Irregularly shaped tests were measured for length and width of the aperture and for the size of the whole test. If a specimen possessed spines, the length of one randomly selected spine was measured. The best-preserved specimen of each taxon was photographed with an optical microscope and a scanning electron microscope (SEM). We found 41 taxa of testate amoebae belonging to the genera: Arcella, Centropyxis, Cucurbitella, Cyclopyxis, Cyphoderia, Difflugia, Euglypha, Lesquereusia, Pentagonia, Pseudodifflugia and Scutiglypha. Twelve species not previously reported for Mexico were recorded, along with 13 varieties. The average number of taxa recorded in each lake was eight, and the highest taxonomic richness was 18. The taxon found in the greatest number of lakes was Centropyxis aculeata var. aculeata. Taxonomic richness varied among lakes in the same region. This could reflect lake-specific differences in environmental conditions, underscoring the need for more detailed studies that include collection of data on physical and chemical variables in the lakes. Our results highlighted the need of further studies for the distribution patterns and ecology of lacustrine testate amoebae.

scholarly journals Ethanolic Extract of Algerian Propolis Induced Cell Damage in Staphylococcus Aureus: A Promising Alternative as a Natural Bio-Preservative in Food Products

2020 ◽  
Vol 49 (4) ◽  
pp. 505-514
Author(s):  
I. K. Bedaida ◽  
S.H.D. Masry ◽  
B. Mamache ◽  
M.G. Shehata ◽  
L. Benammar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Damage ◽  
Ethanolic Extract ◽  
Food Products ◽  
Underlying Mechanism ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Promising Alternative ◽  
Ethanolic Extract Of Propolis ◽  
Scanning Electron

This study describes the antistaphylococcal mechanism of the ethanolic extract of Algerian propolis on Staphylococcus aureus ATCC 25923. To investigate the underlying mechanism of action of the ethanolic extract of propolis, bacteriolysis, bacterial death, leakage of potassium, proteins, nucleic components, and scanning electron microscopic studies were conducted. The results showed that the minimum inhibitory concentration (MIC) of ethanolic extract of propolis against Staphylococcus aureus ATCC 25923 was 39 μg ml–1. The extract displayed significant bactericid activity against S. aureus in a time and concentration dependant manner. Its mode of action was evident from the increase of K+ efflux and nucleotide leakage. These results were confirmed by Scanning Electron Microscopy (SEM) that showed remarkable morphological and ultrastructural changes in S. aureus after exposure to 1MIC and 2MIC concentrations. The overall study contributed to the understanding of the antistaphylococcal mechanism of ethanolic extract of propolis. It emphasizes its potential to be used as an important natural bio-preservatives in food products.

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