scholarly journals Role of Band 3 in the Erythrocyte Membrane Structural Changes Under Isotonic and Hypotonic Conditions

10.5772/64964 ◽  
2017 ◽  
Author(s):  
Ivana Pajic‐Lijakovic ◽  
Milan Milivojevic
Keyword(s):  
Erythrocyte Membrane ◽  
Structural Changes ◽  
Band 3

scholarly journals Eryptotic Phenotype in Chronic Myeloid Leukemia: Contribution of Neutrophilic Cathepsin G

Anemia ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Rukmini Govekar ◽  
Poonam Kawle ◽  
Renjan Thomas ◽  
Suresh Advani ◽  
Sheena PV ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Erythrocyte Membrane ◽  
Myeloid Leukemia ◽  
Band 3 ◽  
Cathepsin G ◽  
Myeloproliferative Disease ◽  
Pathological Conditions ◽  
First Time ◽  
Erythrocyte Membrane Proteins

In pathological conditions with concurrent neutrophilia, modifications of erythrocyte membrane proteins are reported. In chronic myeloid leukemia (CML), a myeloproliferative disease wherein neutrophilia is accompanied by enhanced erythrophagocytosis, we report for the first time excessive cleavage of erythrocyte band 3. Distinct fragments of band 3 serve as senescent cell antigens leading to erythrophagocytosis. Using immunoproteomics, we report the identification of immunogenic 43 kDa fragment of band 3 in 68% of CML samples compared to their detection in only 38% of healthy individuals. Thus, excessive fragmentation of band 3 in CML, detected in our study, corroborated with the eryptotic phenotype. We demonstrate the role of neutrophilic cathepsin G, detected as an immunogen on erythrocyte membrane, in band 3 cleavage. Cathepsin G from serum adsorbs to the erythrocyte membrane to mediate cleavage of band 3 and therefore contribute to the eryptotic phenotype in CML.

Role of Mechanical Stress on the Transglutaminase -Mediated Crosslinking of Erythrocyte Membrane Proteins.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1588-1588
Author(s):  
Edgar Gutierrez ◽  
Lanping Amy Sung
Keyword(s):  
Membrane Proteins ◽  
Mechanical Stress ◽  
Erythrocyte Membrane ◽  
Calcium Influx ◽  
Mechanical Deformation ◽  
Band 3 ◽  
Ionophore A23187 ◽  
Acyl Acceptor ◽  
Erythrocyte Membrane Proteins

Abstract The life-span of erythrocytes is relatively constant within species and it may be determine by the number of times the cell passes through the circulatory system — enduring repeated cycles of mechanical stress. The intrinsic transglutaminase is the major enzyme capable of catalyzing covalent γ-glutamyl-ε-lysine crosslinks that enhance erythrocyte membrane rigidity. Here we report the cloning of mouse erythrocyte transglutaminase (TG) and the role of mechanical stress on the TG-mediated crosslinking of erythrocyte membrane proteins. TG was PCR cloned from reticulocyte cDNA by using consensus primers. Northern blot analysis of the polyA+ mRNA revealed the TG transcript to be 4.6 kb. Recombinant TG was expressed in yeast and the enzymatic crosslinking was detected by labeling glutamine (Q) acyl-donors in inside out vesicles (IOVs) with fluorescent dansylcadaverine (DNC), which serves as the acyl-acceptor. Crosslinking of spectrin/ankyrin, protein 4.1, and band 3 regions (known Q-donors) by TG required CaCl2 at 0.1–0.25 mM and was regulated by both GTP (optimal at 0.01–0.05 mM) and ATP (optimal at 0.5–2.0 mM) with inhibitory effects at higher concentrations. Protein 4.2 (P4.2), a TG pseudo-enzyme, and the cytoplasmic domain of band 3 (cdb3) were also produced recombinantly which allowed for an in-vitro model to test molecular interactions with TG. Specifically, the crosslinking of cdb3 by TG and the binding of P4.2 and TG to cdb3 were examined. A rise in [CaCl2] to near 1 mM showed increased activity of TG (~75% of maximal activity) together with a slight decrease in TG binding affinity to cdb3 (~25% decrease). The crosslinking of cdb3 by TG was inhibited by P4.2, however the presence of P4.2 facilitated the binding of TG to cdb3. The analysis of endogenous TG activity in intact erythrocytes subjected to mechanical stress by hypo-osmolarity (equi-biaxial stretch) or shear stress (anisotropic extension) was also performed. Hypo-osmotically stressed DNC-loaded erythrocytes in the presence of 2 mM [CaCl2] produced a profile with a less intense crosslinking as compared to that of IOVs. In addition, two novel Q-donors (Q1 and Q2) that required mechanical deformation of the membrane to be crosslinked were discovered. Mechanical shearing of erythrocytes in a viscometer produced a similar profile, again with Q2 being the most crosslinked Q-donor. The ratio of Q2/band 3 crosslinking under shear, however, was two fold greater than that under hypo-osmotically induced stress, indicating that varying degrees of crosslinking may be induced by different modes of mechanical stress. Interestingly, Q2 also became crosslinked in IOVs prepared from erythrocytes previously hyposmotically incubated in the presence of extracellular calcium. The importance of mechanical deformation and calcium influx in the binding of Q2 to membrane-associated proteins was further supported by the findings that calcium introduced into erythrocytes using ionophore A23187 alone was not sufficient to induce the crosslinking of Q2. Together these experiments support our hypothesis that periodic mechanical stress may serve as an inherent molecular timer. It is likely that the activation of TG by transient increases in near-membrane calcium concentrations may lead to the accumulation of crosslinks of proteins at the membrane and an eventual entrapment of less deformable erythrocytes in the sinusoids in the spleen followed by subsequent phagocytosis through the recognition of band 3 auto-antibodies.

Economic Growth: New Problems and New Risks

2006 ◽  
pp. 20-37 ◽  
Author(s):  
M. Ershov
Keyword(s):  
Economic Growth ◽  
Foreign Exchange ◽  
Driving Force ◽  
Structural Changes ◽  
Rate Of Growth

The economic growth, which is underway in Russia, raises new questions to be addressed. How to improve the quality of growth, increasing the role of new competitive sectors and transforming them into the driving force of growth? How can progressive structural changes be implemented without hampering the rate of growth in general? What are the main external and internal risks, which may undermine positive trends of development? The author looks upon financial, monetary and foreign exchange aspects of the problem and comes up with some suggestions on how to make growth more competitive and sustainable.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

2019 ◽  
Vol 12 (4) ◽  
pp. 311-323 ◽  
Author(s):  
Salvatore Benvenga ◽  
Antonio Micali ◽  
Giovanni Pallio ◽  
Roberto Vita ◽  
Consuelo Malta ◽  
...  
Keyword(s):  
Structural Changes ◽  
Natural Antioxidants ◽  
Minor Role ◽  
Positive Role ◽  
Testosterone Levels ◽  
Tnf Α ◽  
Testicular Lesions ◽  
A Minor ◽  
Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

scholarly journals Exploring Mucin as Adjunct to Phage Therapy

2021 ◽  
Vol 9 (3) ◽  
pp. 509
Author(s):  
Amanda Carroll-Portillo ◽  
Henry C. Lin
Keyword(s):  
Pathogenic Bacteria ◽  
Structural Changes ◽  
Phage Therapy ◽  
Bacterial Species ◽  
Gi Tract ◽  
Beneficial Bacteria ◽  
Phage Cocktail ◽  
Small Intestinal ◽  
Gastrointestinal Dysbiosis

Conventional phage therapy using bacteriophages (phages) for specific targeting of pathogenic bacteria is not always useful as a therapeutic for gastrointestinal (GI) dysfunction. Complex dysbiotic GI disorders such as small intestinal bowel overgrowth (SIBO), ulcerative colitis (UC), or Crohn’s disease (CD) are even more difficult to treat as these conditions have shifts in multiple populations of bacteria within the microbiome. Such community-level structural changes in the gut microbiota may require an alternative to conventional phage therapy such as fecal virome transfer or a phage cocktail capable of targeting multiple bacterial species. Additionally, manipulation of the GI microenvironment may enhance beneficial bacteria–phage interactions during treatment. Mucin, produced along the entire length of the GI tract to protect the underlying mucosa, is a prominent contributor to the GI microenvironment and may facilitate bacteria–phage interactions in multiple ways, potentially serving as an adjunct during phage therapy. In this review, we will describe what is known about the role of mucin within the GI tract and how its facilitation of bacteria–phage interactions should be considered in any effort directed at optimizing effectiveness of a phage therapy for gastrointestinal dysbiosis.

scholarly journals Structural and Technological Approach to Reveal the Role of the Lipid Phase in the Formation of Soy Emulsion Gels with Chia Oil

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Ana M. Herrero ◽  
Claudia Ruiz-Capillas
Keyword(s):  
Raman Spectroscopy ◽  
Structural Properties ◽  
Structural Changes ◽  
Protein Secondary Structure ◽  
Lipid Phase ◽  
Α Helix ◽  
Β Sheet ◽  
Shed Light ◽  
Chia Oil

Considerable attention has been paid to emulsion gels (EGs) in recent years due to their interesting applications in food. The aim of this work is to shed light on the role played by chia oil in the technological and structural properties of EGs made from soy protein isolates (SPI) and alginate. Two systems were studied: oil-free SPI gels (SPI/G) and the corresponding SPI EGs (SPI/EG) that contain chia oil. The proximate composition, technological properties (syneresis, pH, color and texture) and structural properties using Raman spectroscopy were determined for SPI/G and SPI/EG. No noticeable (p > 0.05) syneresis was observed in either sample. The pH values were similar (p > 0.05) for SPI/G and SPI/EG, but their texture and color differed significantly depending on the presence of chia oil. SPI/EG featured significantly lower redness and more lightness and yellowness and exhibited greater puncture and gel strengths than SPI/G. Raman spectroscopy revealed significant changes in the protein secondary structure, i.e., higher (p < 0.05) α-helix and lower (p < 0.05) β-sheet, turn and unordered structures, after the incorporation of chia oil to form the corresponding SPI/EG. Apparently, there is a correlation between these structural changes and the textural modifications observed.

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