Interactions of Aβ(1–40) with Glycerophosphocholine and Intact Erythrocyte Membranes: Fluorescence and Circular Dichroism Studies

Deposition of amyloid peptide in human brain in the form of senile plaques is a neuropathological hallmark of Alzheimers disease (AD). Levels of a phospholipid breakdown product, glycerophosphocholine (GPC), also increase in AD brain. The effect of GPC on amyloid (1–40) peptide (A) aggregation in PBS buffer was investigated by circular dichroism and fluoresence spectroscopy; interactions of A and GPC with the intact erythrocyte membrane was examined by fluoresence spectroscopy. Fluorescamine labeled A studies indicate GPC enhances A aggregation. CD spectroscopy reveals that A in the presence of GPC adopts 14% more -sheet structure than does A alone. Fluorescamine anisotropy measurements show that GPC and A interact in the phospholipid head-group region of the erythrocyte membrane. In summary, both soluble A and GPC insert into the phospholipid head-group region of the membrane where they interact leading to -sheet formation in soluble A which enhances A aggregation.     

Structural studies of the glycopeptides of B-chain of cinnamomin – a type II ribosome-inactivating protein by nuclear magnetic resonance

Cinnamomin is a plant type II ribosome-inactivating protein (RIP) isolated from the seeds of Cinnamomum camphora. It consists of two nonidentical polypeptide chains (A- and B-chain) held together through one disulfide linkage. Its A- and B-chain contain 0.3% and 3.9% sugars respectively. The B-chain of cinnamomin was digested by pronase E and then the liberated glycopeptides were separated from non-glycopeptides by gel filtration chromatography on a Bio-Gel P-4 column. Three crude glycopeptides were obtained by continuing chromatography over anion-exchange resin (AG1-X2) in the buffer of 2% pyridine-acetic acid (pH 8.3) with a polygradient elution system. Through further purification by the gel filtration chromatography and HPLC, three major glycopeptides, GP1, GP2 and GP3 were obtained. Mainly by two-dimensional Nuclear Magnetic Resonance (NMR) including TOCSY, DQF-COSY, NOESY, HMQC and HMBC, their primary structures were analyzed as: Man1,3Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4GlcNAc1-(Gly-)Asn-Asn-Thr(GP1), Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4(Fuc1,3)GlcNAc1-Asn-Ala-Thr(GP2),Man1,6(Man1,3)Man1,6(Man1,2 Man1,3)Man1,4GlcNAc1,4GlcNAc1-(Ala-)Asn-Gly-Thr(GP3).     

β-Ether cleavage of the lignin model compound 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether and derivatives by Phanerochaete chrysosporium

The white rot basidiomycete Phanerochaete chrysosporium metabolized 4-ethoxy-3-methoxyphenyl-glycerol--guaiacyl ether (V) in low nitrogen, stationary cultures under which conditions the ligninolytic enzyme system is expressed. 4-Ethoxy-3-methoxyphenylglycerol XIII, guaicol and 4-ethoxy-3-methoxybenzyl alcohol (II) were isolated as metabolic products. Exogenously added XIII was rapidly converted to 4-ethoxy-3-methoxybenzyl alcohol indicating that it is an intermediate in the metabolism of V. P. chrysosporium also metabolized 1-(4-ethoxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-3-hydroxypropane VI. The degradation pathway for this dimer also included initial -ether cleavage and -hydroxylation of the diol product 1-(4-ethoxy-3-methoxyphenyl) 2,3 dihydroxypropane (XI) to yield the triol XIII which was cleaved at the , bond to yield 4-ethoxy-3-methoxybenzyl alcohol. Finally P. chrysosporium also cleaved the dimer 1-(4-ethoxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1-hydroxypropane (VIII) at the -ether linkage yielding 1-(4-ethoxy-3-methoxyphenyl) 1,2 dihydroxypropane (IX) which was subsequently cleaved at the , bond to yield II. All of the results indicate that oxidative -ether cleavage is an important initial reaction in the metabolism of -aryl ether lignin substructure dimeric compounds. Metabolities were identified after comparison with chemically synthesized standards by gas liquid chromatography-mass spectrometry.Abbreviations GLC Gas liquid chromatography - TMSi trimethylsilyl - TLC thin layer chromatography     

Reflection of the Intelligence Structure in the Spatiotemporal Features of the Baseline EEG

The EEG correlates of the verbal, numerical, and figural IQ components according to the power and coherence characteristics of the baseline EEG in six frequency bands were studied taking into account personality traits of subjects (extroversion, neuroticism, psychoticism, and anxiety). Analysis of variance and correlation showed that a decreased power of the low-frequency _{1, 2}and ₁ rhythms and increased EEG power in the ₂ band with the right-hemispheric dominance were characteristic of persons with higher intelligence. These EEG characteristics were associated with increased interhemispheric interaction according to the coherence indices and increased coherence within the right hemisphere. Each of the intelligence components (verbal, numerical, and figural) was characterized by a specific baseline frequency–spatial EEG pattern distinguished by specific interactions, predominantly, between the frontal and caudal cortical regions in the and/or ₂ frequency bands.     

A comparison of male and female recombination frequency in wheat using RFLP maps of homoeologous group 6 and 7 chromosomes

A novel approach was used to compare male and female recombination rates in wheat. Doubled haploid lines were developed from an F₁ using two distinct approaches: the anther-culture technique and the Hordeum bulbosum system, from which sets of lines were developed from male and female meioses, respectively. The genotype of the lines was established at RFLP and isozyme markers polymorphic on chromosomes of homoeologous groups 6 and 7, and male and female linkage maps were calculated using this information. The markers in one segment of chromosome 6B exhibited disturbed segregation frequencies in the anther-culture population. The male and female maps differed significantly in recombination frequency between some markers on two chromosomes, and these were consistent in direction within chromosomes and inconsistent in direction between chromosomes. In two of the four chromosomes studied the male map was much longer than the female map. These results suggest that significant differences may exist in male and female recombination frequencies in bread wheat which are specific to certain chromosomal segments but are inconsistent in direction between chromosomes. Other factors, such as environmental influences, may also be important in creating differences.     

Endocrine cells in the human fetal small intestine

Summary In this report we describe the time of appearance and ultrastructural features of enteroendocrine cells (EECs) in the human fetal small intestine (SB) between 9 and 22 weeks gestation. Thirteen distinctive EECs were identified in fetal SB. Two of these, not found in normal adult SB, appeared within the stratified epithelium of the proximal SB at 9–10 weeks. They were arbitrarily termed primitive and precursor cells. As in all fetal EECs, the pale cytoplasm of the primitive cell contains a distinctive population of secretory granules (SGs). Primitive cell SGs average 200–330 nm; some have dense cores with lucent halos while others are filled with a homogeneous dense or flocculent material. The SGs of the precursor cells are larger, averaging up to 1 m in diameter and their contents vary in electron density. A third group of cells not described in normal adult SB was arbitrarily termed transitional cells. These have two populations of SGs; one resembles the SGs of the precursor cells, and the other resembles the SGs of some of the specific adult type EECs. Transitional EC, S, I and G cells are seen. In addition, mature appearing EC, S, G, I, L, D, and D₁ cells were identified by 12 weeks of gestation. The primitive, precursor, and transitional cells may represent sequential developmental precursors of adult type EECs.Supported by Research Grant AM-17537 from the National Institutes of Health, Besthesda, MarylandThe authors would like to thank Ms. Linda Barstein for her excellent technical assistance     

Features of cerebral support of verbal processes in children with dysgraphia and dyslexia

Comprehensive neuropsychological and electroencephalographic examination of children with dysgraphia and dyslexia demonstrated local EEG anomalies in various zones of the cortex in both hemispheres, mainly in the posterotemporal and/or anterior regions of the left and the posterotemporal regions of the right hemisphere. The character of speech disturbances depended considerably on the localization of the baseline EEG anomalies: disturbances of motor components of writing prevailed when these anomalies were localized in the anterior parts of the left hemisphere, while phonological and morphological speech disturbances were noted in children with local anomalies in the temporal regions of both hemispheres and in posterior association regions, mainly in the right hemisphere. Spectral and correlation analyses of the EEG demonstrated the features of the cerebral organization of verbal activity in children with dysgraphia and dyslexia, namely, weakened intra- and interhemispheric integration of electrical activity of different regions of the brain cortex, particularly temporal and posterior association regions, and predominance of integration based on low-frequency EEG components ( and ₁), unlike children without learning disabilities, in whom functional integration of cortical zones involved high-frequency rhythms (₂ and ). On the whole, the results of the study testify to an important role of systemic interactions between the regions of the cortex of both hemispheres in the formation of verbal activity.Translated from Fiziologiya Cheloveka, Vol. 31, No. 2, 2005, pp. 5–12.Original Russian Text Copyright © 2005 by Dmitrova, Dubrovinskaya, Lukashevich, Machinskaya, Shklovskii.     

Role of mitochondria in ethanol tolerance of Saccharomyces cerevisiae

The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate (), fermentation rate (v) or respiration rate () of Saccharomyces cerevisiae wild type strain S288C. Cells which have respiratory metabolism show K _i (ethanol inhibition constant) values for , v and , higher (K _i>1 M) than those of petite mutants or grande strains grown in anaerobiosis (K _i=0.7 M). In addition, the relationship between or v and ethanol concentration is linear in cells with respiratory metabolism and exponential in cells lacking respiration. When functional mitochondria are transferred to petite mutants, the resulting strain shows K _i values similar to those of the grande strain and the inhibition of and v by increasing ethanol concentrations becomes linear.     

Isolation of α and β Brain Tubulin Subunits after Alkaline Treatment of the Protein

We demonstrate here that brain purified tubulin can be dissociated into and subunits at pH > 10 and that the subunits can be separated by using the Triton X-114 phase separation system. After phase partition at pH > 10, tubulin but not tubulin behaves as a hydrophobic compound appearing in the detergent rich phase. After three extractions of the alkaline aqueous phase with Triton X-114, about 90% of the tubulin was recovered in the detergent rich phase. The hydrophobic behavior observed for tubulin after its dissociation at pH 11.5 was not due to an irreversible change of the protein, because when the detergent rich phase containing tubulin was diluted with a buffer solution at pH 7.3 and the solution allowed to partition again, -tubulin is recovered in the aqueous phase. The detergent in the aqueous phase of the and tubulin preparations can be removed up to 90% by 12 h dialysis. The and subunits of tubulin from kidney and liver behave, in this phase separation system, like those of brain tubulin.     

Inhibition of protein synthesis enhances the lytic effects of tumor necrosis factor α and interferon γ in cell lines derived from gynecological malignancies

Summary Few clinical responses have occurred in preliminary studies using the cytokines tumor necrosis factor (TNF) or interferon (IFN) in cancer patients. This may be related to the observation that many malignant cell lines are resistant to lysis by these cytokinesin vitro. Resistance to lysis by TNF or IFN in many cells is controlled by a protein-synthesis-dependent mechanism, such that when protein synthesis is inhibited cells become sensitive to lysis by these cytokines. Because there is some evidence that TNF and IFN act through different lytic mechanisms and are opposed by different resistance mechanisms, we treated a panel of eight cell lines, five derived from human cervical carcinomas (ME-180, MS751, SiHa, HT-3, and C-33A) and three derived from ovarian carcinomas (Caov-3, SK-OV-3, and NIH: OVCAR-3) with both TNF and IFN to determine whether such combination treatment might maximizein vitro cell lysis. Our results showed that pretreatment with IFN followed by exposure to TNF in the presence of protein synthesis inhibitors increased lysis of seven of the eight cell lines above that seen with either TNF or IFN and inhibitors of protein synthesis. Only the cell line C-33A was resistant to lysis by TNF and IFN, when exposed to these agents both alone and in combination with protein synthesis inhibitors. Clinically, combining the cytokines TNF and IFN with protein synthesis inhibitors may maximize thein vivo lytic effects of these cytokines.Supported by American Cancer Society Career Development Award 90-221     

Changes in the Central Regulation of the Respiratory Function after a Single Session of Intermittent Normobaric Hypoxia

Correlations between EEG findings and external respiration and gas exchange indices recorded prior to and after a single session of intermittent normobaric hypoxia were calculated by means of the Neirokartograf (MBN) program. Changes in the central regulation of respiration were observed for a period of more than one hour. The hypoxia caused a decline in EEG coherence in the left hemisphere and a decrease in the statistically significant correlations between the bioelectric rhythms of the , , and ranges and the external respiration and gas exchange indices.     

Comparative Study of Effects of Various Sterols and Triterpenoids on Permeability of Model Lipid Membranes

Using permeability to labeled glucose as a criterion of stability for liposomal membranes, a comparative study on stabilizing properties of different sterols and triterpenes in phospholipid bilayer has been carried out as well as on structural peculiarities of sterols responsible for membranolytic properties of cucumarioside G₁ from the cucumaria Eupentacta fraudatris. Stabilizing action of the studied sterols and triterpenoides incorporated in the bilayer decreases in the following order: cholesterol sulfate > cholesterol > ⁵-sterols > -sitosterol > ergosterols > ⁷-sterols > epicholesterol > pregnane > androstane > coprosterol > 14-methylcholest-9(11)-en-3-ol > 4, 14-dimethylcholest-9(11)-en-3-ol > holothurinogenin A₁ > glucoside of cholesterol > -xylosidase of ⁷-sterols > betulin > protopanaxatriol > phosphatidylcholine liposomes without sterol > protopanaxadiol > oleanolic acid. Sterol-dependent membranolytic cucumarioside G₁ practically loses its ability to increase permeability of phospholipid membranes containing sterols obtained from this holothuria as well as coprosterol, epicholestrol, sulfated and glycosylated forms of sterols. The obtained results confirm the sterol hypothesis of the mechanism of membranotropic action of holothuria glycosides and of resistance to them of holothuria cell membranes.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

Homocysteine stimulates the expression of monocyte chemoattractant protein-1 in endothelial cells leading to enhanced monocyte chemotaxis

The effect of intraperitoneal administration of tocopherol (100 mg/kg wt/24 h) on ascorbate (0.4 mM) induced lipid peroxidation of mitochondria and microsomes isolated from rat liver and testis was studied. Special attention was paid to the changes produced on the highly polyunsaturated fatty acids C20:4 n6 and C22:6 n3 in liver and C20:4 n6 and C22:5 n6 in testis. The lipid peroxidation of liver mitochondria or microsomes produced a significant decrease of C20:4 n6 and C22:6 n3 in the control group, whereas changes in the fatty acid composition of the tocopherol treated group were not observed. The light emission was significantly higher in the control than in the tocopherol treated group. The lipid peroxidation of testis microsomes isolated from the tocopherol group produced a significant decrease of C20:4 n6 , C22:5 n6 and C22:6 n3, these changes were not observed in testis mitochondria. The light emission of both groups was similar. The treatment with tocopherol at the dose and times indicated showed a protector effect on the polyunsaturated fatty acids of liver mitochondria, microsomes and testis mitochondria, whereas those fatty acids situated in testis microsomes were not protected during non enzymatic ascorbateFe²⁺ lipid peroxidation. The protector effect observed by tocopherol treatment in the fatty acid composition of rat testis mitochondria but not in microsomes could be explained if we consider that the sum of C20:4 n6 + C22:5 n6 in testis microsomes is 2-fold than that present in mitochondria.     

Restriction fragment analysis of ‘null’ forms at the Gli-1 loci of bread and durum wheats

Summary Wheat accessions lacking some of the - and -gliadin components encoded by the Gli-1 loci on the short arm of chromosome 1D in bread wheat and chromosome 1A in durum wheat were studied by two-dimensional polyacrylamide gel electrophoresis and restriction fragment analysis. Digested genomic DNAs of normal and null forms were probed with a cDNA clone related to -/-gliadins and with a genomic clone encoding an LMW subunit of glutenin. The hybridisation patterns with the -/-gliadin probe were similar to those of cvs Chinese Spring and Langdon used as standards for bread and durum wheats, respectively, but several restriction fragments located on the 1D chromosome of bread wheat and the 1A chromosome of durum wheat were absent in the null forms. In addition, specific LMW glutenin fragments encoded by the same chromosomes were also absent in the null forms, suggesting that simultaneous deletions of blocks of genes for both -/-gliadins and LMW glutenins had occurred. Comparisons of the protein and RFLP patterns enabled some proteins to be mapped to specific restriction fragments.     

Formation of the Interaction between the Wave Components of the Main EEG Rhythms in Children up to Five Years of Age

Using the analysis of the interaction between EEG components [1], the authors studied the regularities of the formation of the EEG wave structure in 36 children aged 4 to 7 months, 2 to 3 years, and 4 to 5 years. The EEG of 4- to 7-month-old children had a relatively organized temporal structure, whose components were connected mainly with those of the slow-wave range. This structure is reproduced in most of the leads and is more stable in the anterior cortical areas than in the posterior ones. The waking 2- to 5-year-old children had two functional nuclei in the relation structure of the EEG components characterized by statistically significant enhancement in the probability of the consecutive appearance of waves of certain ranges. These nuclei include a slow-wave nucleus in the range of the ₂–₁-frequencies and an alpha-nucleus in the ₁- and ₂-ranges (₂ and ₁ 2- to 3-year-old children) of the EEG frequencies. The relations between the components of the slow-wave nucleus begin to form in infants, prevail in 2- to 3-year-old children, and weaken by the age of 4 to 5 years. A trend is observed in 2- to 5-year-old children towards an increase in the average frequency of the waves that form the slow-wave nucleus. The temporal (strengthening interaction between the waves) and spatial organization of the interaction between the wave components of the alpha-nucleus is accelerated at the age of 4 to 5 years. The average frequency of the components forming this nucleus gradually increases with the children's age from 4 to 7 months to 4 to 5 years. Competitive relations exist between the two nuclei, characterized by a significant decrease in the probability of transitions between the components of different nuclei. The ₂-component may play a special role of the connecting link between the nuclei at the age of 4 to 5 years, the interwave transition from the - to -frequencies and from the latter to the -range being effected by a leaplike rather than smooth frequency increase. The character of local and spatial rearrangements of the EEG temporal structure detected in this study reflects a gradual morphofunctional maturation of the brain as a system that maintains the specific features of self-regulation mechanisms and coordination of the intersystem interactions at various stages of a child's development.     

Structural and functional properties of proteasome activator PA28

The proteasome activator PA28 or 11S regulator is a protein complex composed of two different but homologous polypeptides, termed PA28 and PA28. The purified activator protein (_200 kDa) is a ring-shaped heteromultimer containing the two polypeptides, possibly with an _{3 3} stoichiometry. The activator, which by itself shows no hydrolytic activity elicits activation of the proteasome's multiple peptidase activities by binding to the terminal rings of the proteinase. In vitro, active PA28 can be reconstituted from isolated and subunits, yielding two different oligomers: with the single subunit, PA28 homomultimers with moderate stimulatory activity toward 20S proteasomes are obtained whereas isolated -subunits are unable to form oligomers and are devoid of stimulatory activity. However, in the presence of both subunits, heteromultimers form, concomitant with restoration of full stimulatory activity. The recent finding that PA28 modulates the proteasome-catalyzed production of antigenic peptides presented to the immune system on MHC class I molecules indicates a cellular function of the activator in antigen processing. Abbreviations: IFN – interferon; LMP – low molecular weight peptide; MHC – major histocompatibility complex.     

The relation of proton motive force,adenylate energy charge and phosphorylation potential to the specific growth rate and efficiency of energy transduction inBacillus licheniformis under aerobic growth conditions

The magnitude of the proton motive force (p) and its constituents, the electrical () and chemical potential (-ZpH), were established for chemostat cultures of a protease-producing, relaxed (rel ^–) variant and a not protease-producing, stringent (rel ⁺) variant of an industrial strain ofBacillus licheniformis (respectively referred to as the A- and the B-type). For both types, an inverse relation of p with the specific growth rate was found. The calculated intracellular pH (pH_in) was not constant but inversely related to . This change in pH_in might be related to regulatory functions of metabolism but a regulatory role for pH_in itself could not be envisaged. Measurement of the adenylate energy charge (EC) showed a direct relation with for glucose-limited chemostat cultures; in nitrogen-limited chemostat cultures, the EC showed an approximately constant value at low and an increased value at higher . For both limitations, the ATP/ADP ratio was directly related to .The phosphorylation potential (G'p) was invariant with . From the values for G'p and p, a variable H⁺/ATP-stoichiometry was inferred: H⁺/ATP=1.83+0.52µ, so that at a given H⁺/O-ratio of four (4), the apparent P/O-ratio (inferred from regression analysis) showed a decline of 2.16 to 1.87 for =0 to _max (we discuss how more than half of this decline will be independent of any change in internal cell-volume). We propose that the constancy of G'p and the decrease in the efficiency of energy-conservation (P/O-value) with increasing are a way in which the cells try to cope with an apparent less than perfect coordination between anabolism and catabolism to keep up the highest possible with a minimum loss of growth-efficiency. Protease production in nitrogen-limited cultures as compared to glucose-limited cultures, and the difference between the A- and B-type, could not be explained by a different energy-status of the cells.Abbreviations CCCP carbonylcyanide-p-trichloromethoxyphenylhydrazone - DW dry weight of biomass - F Faraday's constant, 96.6 J/(mV × mol) - Fo chemostat outflow-rate (ml/h) - FCCP carbonylcyanide-p-trifluoromethoxyphenylhydrazone - G'p phosphorylation potential, the Gibbs energy change for ATP-synthesis from ADP and P_i - G'⁰p standard Gibbs energy change at specified conditions - H⁺/ATP number of protons translocated through - ATP synthase in synthesis of one ATP - H⁺/O protons translocated during transfer of 2 electrons from substrate to oxygen - specific growth rate (1/h) - _H+ transmembrane electrochemical proton potential, J/mol - M_b molar weight (147.6 g/mol) of bacteria with general cell formula C_6.0H_10.8O_3.0N_1.2 - pH_out,in extracellular, intracellular pH - P_i (intracellular) inorganic phosphate - p proton motive force, mV - pH transmembrane pH-difference - transmembrane electrical potential, mV - P/O number of ADP phosphorylated to ATP upon reduction of one O^2– to H₂O by two electrons transferred through the electron transfer chain - P/O (H⁺/O) × (H⁺/ATP)^–1 - P/O_F, P/O_N P/O with the two electrons donated by resp. (NADH + H⁺) and FADH - q specific rate of consumption or production (mol/g DW × h) - rel ⁺,rel ^– stringent, relaxed genotype - R universal gas constant, 8.36 J/(mol × degree) - T absolute temperature - TPMP⁺ triphenylmethylphosphonium ion - TPP⁺ tetraphenyl phosphonium ion - Y growth yield, g DW/mol - Z conversion constant=61.8 mV for 310 K (37 °C) - ZpH transmembrane proton potential or chemical potential, mV     

Primary structure of the hemoglobin beta-chain of rose-ringed parakeet (Psittacula krameri)

The primary structure of Rose-ringed Parakeet hemoglobin -chain was established, completing the analysis of this hemoglobin. Comparisons with other avian -chains show variations smaller than those for the corresponding -chains. There are 11 amino acid exchanges in relationship to the only other characterized psittaciform -chain, and a total of 35 positions are affected by differences among all avian -chains analyzed (versus 61 for the -chains). At three positions, the Psittacula -chain has residues unique to this species. Three ₁₁ contacts are modified, by substitutions at positions 51, 116, and 125.