Dimeric hemoglobins from the arcid blood clam, Noetia ponderosa. Structure and functional properties

The hemoglobin found in the nucleated erythrocytes of the arcid blood clam Noetia ponderosa is heterogeneous and consists of two electrophoretic components, Hb-Major and Hb-Minor, present in about 80% and 20% proportions, respectively. Both components are hemoglobin dimers over a wide concentration range based on light-scattering measurements. No higher aggregation states are observed. The oxygen binding by Hb-Major and Hb-Minor is characterized by p50 values of 16.8 and 8.7 mm of Hg and Hill coefficients of 1.4 and 1.2, respectively, at pH 7.0 and 25 degrees C. Neither component exhibits an alkaline Bohr effect. An unusual nonlinear Hill plot is observed for Hb-Major. Hb-Major is composed of two different polypeptide chains and thus is a heterodimer based on sodium dodecyl sulfate/urea-polyacrylamide gel electrophoresis and reverse phase high performance liquid chromatography. By the same methods, Hb-Minor is a homodimer and may share a common chain with Hb-Major. Amino acid compositions of the two hemoglobins indicate 2 histidines/polypeptide chain which are presumably involved in the coordination of the heme iron. Visible absorption spectra indicate the heme environment is normal in the oxy state but perhaps more constrained in the deoxy state. Oxygen binding as a function of temperature and concentration and binding by the intact erythrocytes indicates the absence of intracellular regulators of oxygen binding.     

Structural and functional analysis of spectrin from neonatal erythrocytes

Spectrin was purified by rate zonal sedimentation from low-salt extracts of red cell membranes from neonatal and adult blood. Neonatal and adult spectrin cosedimented in sucrose density gradients, comigrated on SDS gels and displayed identical two-dimensional chymotryptic 125I-labelled peptide maps. Neonatal spectrin and adult spectrin exhibited equivalent affinity for both neonatal and adult ankyrin sites on spectrin-depleted inverted membrane vesicles. Purified spectrin heterodimers from neonatal and adult red cells displayed similar self-association equilibrium constants in a fluid phase dimer-dimer association assay. These results suggest that the unique membrane characteristics of the neonatal erythrocyte are not due to a structural or functional alteration of spectrin. Several alternative hypotheses involving other membrane proteins and their linkages are discussed.     

Morphological and functional changes of mitochondria from density separated trout erythrocytes

Density separated trout erythrocytes, using a discontinuous Percoll gradient, yielded three distinct subfractions (top, middle and bottom) since older cells are characterized by increasing density. Cells from each subfraction were incubated with mitochondria-specific fluorescent probe Mitotracker and JC-1 in order to assess mitochondrial mass and membrane potential by means of cytofluorimetric analysis, confocal microscopy and subsequent computer-aided image analysis allowing a detailed investigation at single cell level. Both cytofluorimetric data and image analysis revealed changes in size and redistribution of mitochondria starting from the light fraction to the bottom. In particular in young erythrocytes small mitochondria were detected localized exclusively around the nucleus in a crown-like shape, the middle fraction revealed enlarged mitochondria partially scattered throughout the cytosol, whereas the last fraction represented again mitochondria with reduced size being distinctly dispersed throughout the cytosol in the cells. Concerning membrane potential considerations, our study revealed a dramatic decrease of DeltaPsi(m) in the bottom layer cell mitochondria compared to the top and unusual membrane potential increase of a subpopulation of enlarged mitochondria. DeltapH was also investigated in the three fractions by pretreating the cells with nigericin, allowing to confirm a mitochondrial energetic impairment in older cells.     

Cytological characteristics of erythropoiesis in thalassemia. II. Structural functional characteristics of peripheral blood erythrocytes

In 61 patients affected with thalassaemia of various degrees of seriousness, cytological investigations were carried out on erythrocytes in the peripheral blood. The interferometrically determined changes in the dry mass of erythrocytes, the diminution of the surface potential expressed in electrophoresis, the changes in the membrane structure of erythrocytes which could be represented in the scanner electron microscope were directly dependent on the seriousness of the disease.     

Metabolic characteristics of mitochondria isolated from rabbit brain

Abstract— Data on the metabolic characteristics of mitochondria from rabbit brain have been obtained using low concentrations (100–300 μm) of ¹⁴C-labelled substrates of the Krebs tricarboxylic acid cycle. Oxygen consumption was measured polarographically with a Clark-type electrode. Products of the reactions were separated by chromatography on Dowex-1 columns. Data are reported for relative respiratory quotients of various substrates, respiratory control ratios, accumulation of ¹⁴C in various tricarboxylic acid cycle intermediates and the effect of malate and several inhibitors on these parameters. The data have been compared with similar experiments on mitochondria from rabbit heart. Mitochondria from rabbit brain differ substantially from heart mitochondria: those from brain have a very low capacity for oxidation of acetate and other short chain fatty acids; they do not form j3-hydroxybutyrate; they produce substantial amounts of α-ketoglutarate and require added dicarboxylic acid to yield a maximum respiratory quotient. Like those from heart, brain mitochondria have a high capacity for pyruvate oxidation and a low K_m for this substrate. The results have been discussed and compared with work reported by other investigators.     

Metabolic properties of erythrocytes of normal and genetically anemic mice

The murine hemolytic anemias microcytosis (gene symbol mk), normoblastosis (nb), spherocytosis (sph), and hemolytic (ha) are inherited as autosomal recessive diseases and resemble the human hereditary hemolytic anemias caused by defective enzyme activities in erythrocytes. The activities of 14 different enzymes of the glycolytic and pentose phosphate pathways were compared in erythrocytes from normal and anemic mice, but no quantitative differences suggesting enzyme deficiency were found. There were no major changes in reduced glutathione, NAD, NADP, or methemoglobin content. The rate of entry of glucose into the glycolytic and hexose monophosphate shunt pathways of intact erythrocytes was higher in mk/mk erythrocytes than predicted. Interpretation of studies of erythrocytes from anemic mice is generally complicated by the extremely high reticulocyte and nucleated cell counts in ha/ha, sph/sph, and nb/nb mice.Investigations in Kentucky (Dr. Hutton) were supported by Research Career Development Award 1-K4-AM-70, 186-01 and NIH Research Grant AM 16013-01 from the National Institute of Arthritis and Metabolic Diseases, and those at The Jackson Laboratory (Dr. Bernstein) by NIH Research Grant HD-00254 from the National Institute of Child Health and Human Development, by U.S. Atomic Energy Commission Contract AT(30-1)-1800, and in part by the George W. Perkins Memorial Fund and by income from the Endowment Funds of The Jackson Laboratory. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory Animal Care.     

Thermostability characteristics of glucosephosphate and triosephosphate isomerase in erythrocytes from several species

Significant differences in the thermostability of both glucosephosphate and triosephosphate isomerase were noted among a series of six primate and five nonprimate species. The enzyme structural differences among species, as assessed by thermostability profiling, was greater than expected from electrophoretic mobility patterns. Microheterogeneity of GPI, i.e. differences in thermostability within a species that are not detectable by electrophoresis, was detected in two primate species. Major differences in the levels of erythrocyte enzyme activity were observed with human and cow differing by 18-fold for TPI and baboon and cow differing by seven-fold in GPI activity.     

Proboscis myoglobin of Glycera dibranchiata

• 1.1. A monomeric myoglobin is present in the muscles of the proboscis of the polychaete Glycera dibranchiata. This myoglobin differs in structure and function from the monomeric hemoglobin found in this animal's coelomic cells.
• 2.2. The myoglobin has a very high oxygen affinity and a high carbonmonoxide combination rate. The high oxygen affinity of this myoglobin is well suited physiologically to supply oxygen to muscles of the proboscis which are used in burrowing and feeding.

     

Structural consequences of heme isomerism in monomeric hemoglobins from Glycera dibranchiata

Two-dimensional 1H-NMR methods have been used to assign heme and amino acid proton resonances in both isomeric states of the carbon monoxide complexes of two Glycera dibranchiata monomeric hemoglobins, HbA and HbB. For each hemoglobin, there are small differences in heme pocket structure in the two isomeric forms. The largest structural perturbations associated with heme isomerism involve residues close to pyrrole rings I and II. The positions relative to the heme of phenylalanine CD1 and the proximal histidine ligand are almost unaffected by heme isomerism. These residues probably play a key role in determining the location of the heme within the heme pocket.     

Metabolic effects of dehydroabietic acid on rainbow trout erythrocytes

Oxygen consumption and ATP concentration were measured in rainbow trout erythrocytes incubated in a physiological saline containing 0, 5, 15, 30 or 60 mg/l dehydroabietic acid. DHAA caused a decrease in cellular ATP level and oxygen consumption at concentrations above 15 mg/l. Haemolysis increased markedly, when the cellular ATP concentration decreased below 1 mM. These data suggest that increased breakdown of red cells may be the primary reason for jaundice which is observed in resin acid-toxicated fish.     

青岛市不同功能区冬季空气微生物群落代谢与多样性特征

选取青岛市5个功能区(市区街道、海滨区域、饮用水源地、垃圾填埋场和人工湿地污水处理系统),采用SAS ISO100空气浮游菌采样器于2013年冬季采集空气微生物样品,应用BIOLOG方法分析空气微生物群落代谢功能多样性,阐明群落代谢与环境相关性。结果表明,不同功能区空气微生物群落碳源代谢强度存在差异,代谢稳定时,海滨区域和饮用水源地样品平均光密度值(AWCD)分别为0.302、0.210,而人工湿地、市区街道及垃圾填埋场分别为0.063、0.025和0.034,海滨区域和饮用水源地空气微生物群落碳源代谢强度明显高于其他功能区。不同功能区空气微生物群落Shannon指数和Simpson指数接近,但海滨区域和饮用水源地Mc Intosh指数明显高于其他功能区。海滨区域和饮用水源地空气微生物群落碳源代谢类型丰富,代谢水平高,人工湿地、市区街道和垃圾填埋场碳源代谢类型单一,代谢水平低。5个功能区空气微生物群落碳源代谢差异呈现区域性,分异代谢差异的主要是羧酸类碳源。风速、温度、湿度等非生物因素对空气微生物群落碳源代谢具有不同程度影响,且不同功能区主导非生物因素存在差异。BIOLOG方法可以提供大量多维数据,能够分析样品间微生物群落碳源代谢差异,客观、全面表征空气微生物群落碳源代谢多样性特征,是研究空气微生物群落功能多样性较理想的方法之一。     

Functional characteristics of normal and pathologic erythrocytes

Polarographic titration in a closed cell of blood samples and concentrated Hb solutions was used to study the regulation of the release of oxygen by the red cell. The effect of temperature, polyethylenglycol and metabolites normally found in the erythrocyte was determined by spectrophotometric and polarographic methods. Some pecularities of O2-transport and release in beta-thalassemia, functional hypoxia and Cooley-disease are described.