scholarly journals Structure development in a soft cheese curd model during manufacture in relation to its biochemical characteristics

2002 ◽  
Vol 69 (4) ◽  
pp. 605-618 ◽  
Author(s):  
RACHEL BOUTROU ◽  
MARIE-HELENE FAMELART ◽  
FREDERIC GAUCHERON ◽  
YVON LE GRAET ◽  
JEAN-YVES GASSI ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Structural Changes ◽  
Initial Increase ◽  
Structure Development ◽  
Electron Microscopic ◽  
Biochemical Characteristics ◽  
Manufacture Process ◽  
Soft Cheese ◽  
Cheese Curd ◽  
Hydrolysis Of

The structure development of a soft cheese curd model has been studied in relationship to its rheological properties and its biochemical characteristics (pH, amount and partition of minerals, casein proteolysis) at different technical steps including cutting, drawing, three turns and demoulding. Scanning electron microscopy was used to observe structural changes during the drainage of a fat-free soft cheese. The micrographs provided visual evidence of changes in the casein matrix from casein particles aggregated in clusters to uniform strands observed at the demoulding. The initial increase of loss tangent and of the exponent of the power law between G′ and G′′ and frequency (that were maximal at the second turn) was related to the solubilization of micellar calcium phosphate, while intact caseins and large casein fragments accumulated in the curd. After the second turn, the strength, Youngs' and loss moduli of the curd increased greatly. The hydrolysis of αs1-casein into αs1-I-CN f(24–199) may facilitate the rearrangement of casein particles within the curd. The pH-induced solubilization of calcium phosphate continued throughout the manufacture process but was unexpectedly incomplete at the end of the drainage. Combination of electron microscopic observations with dynamic rheological measurements and chemical and biochemical assessments provided increased knowledge about the structure of soft cheese during drainage, an important but poorly understood cheese making stage.

Electron microscopic study of the structural changes as a function of temperature in anorthite*

1973 ◽  
Vol 138 (1-4) ◽  
pp. 403-418
Author(s):  
M. Czank ◽  
J. Van Landuyt ◽  
H. Schulz ◽  
F. Laves ◽  
S. Amelinckx
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Structural Changes ◽  
Electron Microscopic

New insights into the structural basis of integrin activation

Blood ◽  
2003 ◽  
Vol 102 (4) ◽  
pp. 1155-1159 ◽  
Author(s):  
Jian-Ping Xiong ◽  
Thilo Stehle ◽  
Simon L. Goodman ◽  
M. Amin Arnaout
Keyword(s):  
Conformational Changes ◽  
Structural Changes ◽  
Structural Basis ◽  
Integrin Activation ◽  
Cellular Functions ◽  
Electron Microscopic ◽  
The Past ◽  
Intracellular Signals ◽  
Bidirectional Signaling ◽  
New Hypothesis

Abstract Integrins are cell adhesion receptors that communicate biochemical and mechanical signals in a bidirectional manner across the plasma membrane and thus influence most cellular functions. Intracellular signals switch integrins into a ligand-competent state as a result of elicited conformational changes in the integrin ectodomain. Binding of extracellular ligands induces, in turn, structural changes that convey distinct signals to the cell interior. The structural basis of this bidirectional signaling has been the focus of intensive study for the past 3 decades. In this perspective, we develop a new hypothesis for integrin activation based on recent crystallographic, electron microscopic, and biochemical studies.

Structural Changes on Charring Woods of Dichrostachys and Salix from Southern Africa: The Effect of Moisture Content

IAWA Journal ◽  
1986 ◽  
Vol 7 (3) ◽  
pp. 243-250 ◽  
Author(s):  
Juliet Prior ◽  
K. L. Alvin
Keyword(s):  
Moisture Content ◽  
Southern Africa ◽  
Structural Changes ◽  
Initial Increase ◽  
Dichrostachys Cinerea ◽  
Chemical Changes ◽  
Structural Alterations ◽  
Wood Pyrolysis ◽  
Effect Of Moisture ◽  
Physical And Chemical

Air-dried and saturated cubes of fully developed wood of Dichrostachys cinerea (Leguminosae) and Salix subserrata (Salicaceae) were charred for 60 minutes at 400°C. An initial increase in moisture content caused few structural alterations in Salix but in Dichrostachys it resulted in considerable ray distension and massive deformation of non-gelatinous fibres. An attempt is made to correlate these observations with the physical and chemical changes known to occur during wood pyrolysis.

scholarly journals The effects of simulated microgravity on skeletal muscle of Japanese quail: transmission electron microscopic study

2011 ◽  
Vol 80 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Katarína Holovská ◽  
Viera Almášiová ◽  
Viera Cigánková ◽  
Peter Škrobánek
Keyword(s):  
Skeletal Muscle ◽  
Japanese Quail ◽  
Structural Changes ◽  
Simulated Microgravity ◽  
Negative Impact ◽  
Electron Microscopic ◽  
Giant Mitochondria ◽  
Transmission Electron ◽  
Muscle Tissues ◽  
And Control

The aim of the present study was to investigate the effects of simulated microgravity (hypodynamia) on the structure of the skeletal muscle (m. gastrocnemius) in developing Japanese quail by transmission electron microscopy. Samples of muscle tissues from experimental (n = 28) and control (n = 28) birds were collected at day 7, 14, 28, 42 and 56 of age. The structure of m. gastrocnenmius was changed depending on hypodynamia length. The first extensive structural changes were found on day 14 of age. The mitochondria were enlarged and the spaces between the myofibrils were slightly extended compared to control. The sarcomeres were irregular and lipid droplets occurred in the sarcoplasm. Further developmental changes occurred on day 28 of age. Mitochondria fused into the giant mitochondria which frequently exceeded the length of one sarcomere. Moreover, at 42 days of age, beside the above mentioned changes, sarcoplasmic reticulum was dilated and the number of mitochondrial cristae was reduced. However, the structure of m. gastrocnemius on day 56 was less damaged compared to the damage observed on day 42 of age. Presented results indicate that the continuous stay of male Japanese quail under simulated microgravity has a negative impact on the structure of m. gastrocnemius, but also the ability of muscle tissue to cope with these specific conditions.

scholarly journals STRUCTURAL CHANGES IN THE MICROCIRCULATORY BED OF THE PANCREAS IN RATS WITH EXPERIMENTAL METABOLIC SYNDROME

2018 ◽  
Vol 15 (3) ◽  
pp. 347-353
Author(s):  
T. E. Kuznetsova ◽  
E. L. Ryzhkovskaya ◽  
E. I. Kalinovskaya
Keyword(s):  
Metabolic Syndrome ◽  
Glucose Oxidation ◽  
Structural Changes ◽  
Krebs Cycle ◽  
Electron Microscopic ◽  
Microcirculatory Bed ◽  
The Metabolic Syndrome ◽  
Marginal State ◽  
Inflammatory Changes ◽  
Blood Elements

A complex histological, histochemical and electron microscopic study of the state of the microcirculatory bed of the pancreas and conjugate transformations in the parenchyma of the organ after modeling the metabolic syndrome using a diet high in fats and carbohydrates was carried out. Spasm of arterioles, the marginal state of leukocytes and the desquamation of endotheliocytes into the lumen of a vessel, the stasis of erythrocytes in capillaries were revealed. The endothelial cells of capillaries had signs of increased transport of substances through the vessel walls: pinocytosis, fenestration, loosening of basal membranes. It was observed that capillaries are filled with shaped blood elements, on the luminal surface of endotheliocytes nuclei are protruded and the cytoplasm outgrowth into the lumen of the vessel is formed. At the same time, glucose oxidation accelerated both in the Krebs cycle and along the glycolytic pathway in the endotheliocytes of the vessels of the microcirculatory bed, indicating that the energy was supplied to the cells at a higher level. Disturbances of microcirculation were accompanied by focal destructive and inflammatory changes in the parenchyma of the organ.

scholarly journals Zika virus replication in glioblastoma cells: electron microscopic tomography shows 3D arrangement of endoplasmic reticulum, replication organelles, and viral ribonucleoproteins

2021 ◽  
Author(s):  
Johannes Wieland ◽  
Stefan Frey ◽  
Ulrich Rupp ◽  
Sandra Essbauer ◽  
Rüdiger Groß ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Line ◽  
Zika Virus ◽  
Structural Changes ◽  
Electron Tomography ◽  
Glioblastoma Cells ◽  
Electron Microscopic ◽  
N Protein ◽  
Ribonucleoprotein Complexes ◽  
Infected Cells

AbstractStructural changes of two patient-derived glioblastoma cell lines after Zika virus infection were investigated using scanning transmission electron tomography on high-pressure-frozen, freeze-substituted samples. In Zika-virus-infected cells, Golgi structures were barely visible under an electron microscope, and viral factories appeared. The cytosol outside of the viral factories resembled the cytosol of uninfected cells. The viral factories contained largely deranged endoplasmic reticulum (ER), filled with many so-called replication organelles consisting of a luminal vesicle surrounded by the ER membrane. Viral capsids were observed in the vicinity of the replication organelles (cell line #12537 GB) or in ER cisternae at large distance from the replication organelles (cell line #15747 GB). Near the replication organelles, we observed many about 100-nm-long filaments that may represent viral ribonucleoprotein complexes (RNPs), which consist of the RNA genome and N protein oligomers. In addition, we compared Zika-virus-infected cells with cells infected with a phlebovirus (sandfly fever Turkey virus). Zika virions are formed in the ER, whereas phlebovirus virions are assembled in the Golgi apparatus. Our findings will help to understand the replication cycle in the virus factories and the building of the replication organelles in glioblastoma cells.

scholarly journals Alterations of the thyroid structure and function in experimental hypopinealism

2011 ◽  
Vol 57 (2) ◽  
pp. 32-35
Author(s):  
L A Bondarenko ◽  
L Iu Sergienko ◽  
N N Sotnik ◽  
A N Cherevko
Keyword(s):  
Thyroid Gland ◽  
Structural Changes ◽  
Structure And Function ◽  
Initial Increase ◽  
Histological Structure ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
And Function ◽  
Sexually Mature

The pituitary-thyroid axis of young sexually mature rabbits kept under a 24-hour daylight photoperiod was shown to undergo phase-modulated variations of hormonal activity with its initial increase (during the first month) and subsequent progressive decrease (within 2-5 months after the onset of exposure to light). These changes correlated with the time-dependent fall in the blood T3, T4, and TSH levels. Simultaneously, the animals developed pathological changes in the histological structure of the thyroid gland similar to those in patients with secondary or tertiary hypothyroidism. It is concluded that hormonal and structural changes in the thyroid gland during long-term hypopinealism should be regarded as an experimental model of hypothyroidism of neuroendocrine origin.

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 Preparation and Properties of Nanocellulose from Miscanthus x giganteus

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Valerii A. Barbash ◽  
Olha V. Yashchenko ◽  
Olesia A. Vasylieva
Keyword(s):  
Structural Changes ◽  
Thermochemical Treatment ◽  
Crystallinity Index ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Miscanthus X Giganteus ◽  
X Ray ◽  
Second Stage ◽  
20 Nm ◽  
Hydrolysis Of

Miscanthus x giganteus stalks were used to make organosolvent pulp and nanocellulose. The organosolvent miscanthus pulp (OMP) was obtained through thermal treatment in the mixture of glacial acetic acid and hydrogen peroxide at the first stage and the alkaline treatment at the second stage. Hydrolysis of the never-dried OМP was carried out by a solution of sulfuric acid with concentrations of 43% and 50% and followed by ultrasound treatment. Structural changes and the crystallinity index of OMP and nanocellulose were studied by SEM and FTIR methods. X-ray diffraction analysis confirmed an increase in the crystallinity of OMP and nanocellulose as a result of thermochemical treatment. We show that nanocellulose has a density of up to 1.6 g/cm3, transparency up to 82%, and a crystallinity index of 76.5%. The AFM method showed that the particles of nanocellulose have a diameter in the range from 10 to 20 nm. A thermogravimetric analysis confirmed that nanocellulose films have a denser structure and lower mass loss in the temperature range of 320–440°C compared to OMP. The obtained nanocellulose films have high tensile strength up to 195 MPa. The nanocellulose obtained from OMP exhibits the improved properties for the preparation of new nanocomposite materials.

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