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Benga G.,First Laboratory of Genetic Explorations | Benga G.,Vasile Goldis Western University of Arad | Benga G.,University of Sydney | Benga G.,Romanian Academy of Sciences
European Biophysics Journal | Year: 2013

NMR measurements of the diffusional permeability of the human adult red blood cell (RBC) membrane to water (P d) and of the activation energy (E a,d) of the process furnished values of P d ~ 4 × 10-3 cm/s at 25 C and ~6.1 × 10-3 cm/s at 37 C, and E a,d ~ 26 kJ/mol. Comparative NMR measurements for other species showed: (1) monotremes (echidna and platypus), chicken, little penguin, and saltwater crocodile have the lowest P d values; (2) sheep, cow, and elephant have P d values lower than human P d values; (3) cat, horse, alpaca, and camel have P d values close to those of humans; (4) guinea pig, dog, dingo, agile wallaby, red-necked wallaby, Eastern grey kangaroo, and red kangaroo have P d values higher than those of humans; (5) mouse, rat, rabbit, and "small and medium size" marsupials have the highest values of P d (>8.0 × 10-3 cm/s at 25 C and >10.0 × 10-3 cm/s at 37 C). There are peculiarities of E a,d values for the RBCs from different species. The maximum inhibition of diffusional permeability of RBCs induced by incubation with p-chloromercuribenzene sulfonate varied between 0 % (for the chicken and little penguin) to ~50 % (for human, mouse, cat, sheep, horse, camel, and Indian elephant), and ~60-75 % (for rat, guinea pig, rabbit, dog, alpaca, and all marsupials). These results indicate that no water channel proteins (WCPs) or aquaporins are present in the membrane of RBCs from monotremes (echidna, platypus), chicken, little penguin and saltwater crocodile whereas WCPs from the membranes of RBCs from marsupials have peculiarities. © 2012 European Biophysical Societies' Association. Source

Benga G.,First Laboratory of Genetic Explorations | Benga G.,Vasile Goldis Western University of Arad | Benga G.,Romanian Academy of Sciences
Molecular Aspects of Medicine | Year: 2012

After a decade of work on the water permeability of red blood cells (RBC) Benga group in Cluj-Napoca, Romania, discovered in 1985 the first water channel protein in the RBC membrane. The discovery was reported in publications in 1986 and reviewed in subsequent years. The same protein was purified by chance by Agre group in Baltimore, USA, in 1988, who called in 1991 the protein CHIP28 (CHannel forming Integral membrane Protein of 28 kDa), suggesting that it may play a role in linkage of the membrane skeleton to the lipid bilayer. In 1992 the Agre group identified CHIP28's water transport property. One year later CHIP28 was named aquaporin 1, abbreviated as AQP1. In this review the molecular structure-function relationships of AQP1 are presented. In the natural or model membranes AQP1 is in the form of a homotetramer, however, each monomer has an independent water channel (pore). The three-dimensional structure of AQP1 is described, with a detailed description of the channel (pore), the molecular mechanisms of permeation through the channel of water molecules and exclusion of protons. The permeability of the pore to gases (CO2, NH3, NO, O2) and ions is also mentioned. I have also reviewed the functional roles and medical implications of AQP1 expressed in various organs and cells (microvascular endothelial cells, kidney, central nervous system, eye, lacrimal and salivary glands, respiratory apparatus, gastrointestinal tract, hepatobiliary compartments, female and male reproductive system, inner ear, skin). The role of AQP1 in cell migration and angiogenesis in relation with cancer, the genetics of AQP1 and mutations in human subjects are also mentioned. The role of AQP1 in red blood cells is discussed based on our comparative studies of water permeability in over 30 species. © 2012 Elsevier Ltd. All rights reserved. Source

Benga G.,First Laboratory of Genetic Explorations | Chapman B.E.,University of Sydney | Cox G.C.,University of Sydney | Kuchel P.W.,University of Sydney
Cell Biology International | Year: 2010

As part of a programme of comparative measurements of Pd (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be ~6.3 μm. Pd was measured by using an Mn2+-doping 1H NMR (nuclear magnetic resonance) technique. The Pd (cm/s) values were relatively low: ~2.1×10-3 at 25°C, 2.5×10-3at 30°C, 3.4×10-3 at 37°C and 4.5 at 42°C for the platypus RBCs and ~2.8×10-3 at 25°C, 3.2×10-3 at 30°C, 4.5×10-3 at 37°C and 5.7×10-3 at 42°C for the crocodile RBCs. In parallel with the low water permeability, the Ea,d (activation energy of water diffusion) was relatively high, ~35 kJ/mol. These results suggest that "conventional" WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile. © The Author(s) Journal compilation © 2010 Portland Press Limited. Source

Nicula G.,University of Medicine and Pharmacy, Cluj-Napoca | Balici S.,University of Medicine and Pharmacy, Cluj-Napoca | Florea A.,University of Medicine and Pharmacy, Cluj-Napoca | Mironescu E.,University of Medicine and Pharmacy, Cluj-Napoca | And 3 more authors.
Annals of the Romanian Society for Cell Biology | Year: 2010

In the exhaust of "apartment" heating appliances, as a result of natural gas combustion, in addition to carbon and nitric oxydes or sulphur derivates, there is also particulate matter (PM) containing polyaromatic hydrocarbons and derivates (of which benzopyren is the most notorious carcinogenic compound). The aims of our study were to identify PM in the exhaust (emission) of "apartment" heating appliances installed in apartments in Cluj-Napoca, and to study their aspect and sizes by scanning electron microscopy. The scanning electron microscopic aspects were studied with a Jeol JSM 25S electron microscope, and the PM were sized on the digital images, proving the presence of PM in the exhaust of "apartment" heating appliances. PM size distribution confirms that PM susceptible of being inhaled by breathing: PM 2.5 (diameter below 2.5 μm) and PM 10 (diameter below 10 μm) abound in the exhaust (emission) of "apartment" heating appliances. Source

Benga G.,First Laboratory of Genetic Explorations | Benga G.,Vasile Goldi Western University | Benga G.,Romanian Academy of Sciences
Molecular Aspects of Medicine | Year: 2012

A water channel protein (WCP) or a water channel can be defined as a transmembrane protein that has a specific three-dimensional structure with a pore that provides a pathway for water permeation across biological membranes. The pore is formed by two highly conserved regions in the amino acid sequence, called NPA boxes (or motifs) with three amino acid residues (asparagine-proline- alanine, NPA) and several surrounding amino acids. The NPA boxes have been called the "signature" sequence of WCPs. WCPs are a family of proteins belonging to the Membrane Intrinsic Proteins (MIPs) superfamily. In addition, in the MIP superfamily (with more than 1000 members) there are also proteins with no channel activity. The WCP family include three subfamilies: aquaporins, aquaglyceroporins and S-aquaporins. (1) The aquaporins (AQPs) are water selective or specific water channels, also named by various authors as "orthodox", "ordinary", "conventional", "classical", "pure", "normal", or "sensu strictu" aquaporins); (2) The aquaglyceroporins are permeable to water, but also to other small uncharged molecules, in particular glycerol; this family includes the glycerol facilitators, abbreviated as GlpFs, from glycerol permease facilitators. The "signature" sequence for aquaglyceroporins is the aspartic acid residue (D) in the second NPA box. (3) The third subfamily of WCPs have little conserved amino acid sequences around the NPA boxes, unclassifiable to the first two subfamilies. I recommend to use always for this subfamily the name S-aquaporins. They are also named "superaquaporins", "aquaporins with unusual (or deviated) NPA boxes", "subcellular aquaporins", or "sip-like aquaporins". I also recommend to use always the spelling aquaporin (not aquaporine), and, for various AQPs, the abbreviation AQP followed immediately by the number, (e.g. AQP1), with no space or - which might create confusions with "minus". © 2012 Elsevier Ltd. All rights reserved. Source

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