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1.
Primary structure of hemoglobin of -chain ofColumba livia is presented. The separation of -chain was obtained from globin by ion-exchange chromatography (CMC-52) and reversed-phase HPLC (RP-2 column). Amino acid sequence of intact as well as tryptic digested chain was determined on gas-phase sequencer. Structure is aligned homologously with 21 other species. Among different exchanges, positions 24 (TyrLeu), 26 (AlaGly), 32 (MetLeu), 64 (AspGlu), 113 (LeuPhe), and 129 (LeuVal) are unique to pigeon hemoglobin. The various exchanges in -chain are discussed with reference to evolution and phylogeny. The results show that the order Columbiformes is evolutionarily closer to the order Anseriformes. Since the pigeon is homogeneous, having HbA (A-chain) and lacks D-chain, its phylogenetic placement could be established among birds having single hemoglobin components.  相似文献   

2.
Wang W  Vignani R  Scali M  Sensi E  Cresti M 《Planta》2004,218(3):460-465
To further understand post-translational modifications (PTMs) of plant -tubulin, post-translationally modified -tubulin isoforms from selected tissues of Zea mays L. were examined using two-dimensional electrophoresis and immunoblotting. Except for polyglycylated tubulin, tyrosinated, detyrosinated, acetylated and polyglutamylated -tubulin isoforms were all present in maize tissues. Tyrosinated -tubulin was the predominant variant in all cases, with isoforms 1–4 (5) being the most common components. Leaves exhibited a striking difference in PTM patterns of -tubulin isoforms compared to other tissues examined. In leaves, several major specific isoforms were highly modified by detyrosination, acetylation and polyglutamylation. In pollen and anthers, only the most abundant isoform 3 was acetylated to an appreciable extent, and no acetylated isoform was found in roots. Similarly, in pollen, anthers and roots, only 3 was appreciably polyglutamylated. Additionally, a detyrosinated isoform 6 was present in anthers and in leaves, while the tyrosinated isoform 6 seemed to be pollen specific. These results indicate that certain types of PTM of plant -tubulin preferentially occur in a tissue-specific way.Abbreviations 1-, 2-D one-, two-dimensional - MT microtubule - PTM post-translational modification  相似文献   

3.
The synthesis of the methyl - and -N-dansyl-d-galactosaminides is described using methyl ,-2-azido-2-deoxy-d-galactopyranoside as starting material. This was reduced to the corresponding methyl ,-2-amino-2-deoxy-d-galactopyranoside and then treated with dansyl chloride to yield a mixture of methyl ,-N-dansyl-d-galactosaminides which was separated into individual anomeric forms by flash chromatography on silica gel. Methyl -N-dansyl-d-galactosaminide was used as a fluorescent indicator ligand in continuous substitution titrations to determine the association constants of nonchromophoric carbohydrates with theN-acetyl-d-galactosamine specific lectin fromErythrina corallodendron.Abbreviations ECorL Erythrina corallodendron lectin - MeGalNDns methyl 2-deoxy-2-(5-dimethylamino-1-naphthalenesulfamido)--d-galactopyranoside - MeGalNDns methyl 2-deoxy-2-(5-dimethylamino-1-naphthalenesulfamido)--d-galactopyranoside Dedicated to Hilde De Boeck (1958–1991).  相似文献   

4.
Summary Offspring production over the adult lifespan (b/M whereb is the yearly fledgling or offspring production and 1/M is the mean adult lifespan) is an approximate invariant within both birds and mammals. The two taxa differ, however, in that mammals have bothM and b as invariants (b/M = b/M) while birds do not ( is the age at first breeding). Birds have a surprising cancellation in that bothM andb are –0.25.  相似文献   

5.
Sequence analysis of the rearranged T-cell receptor a chain gene segments from an influenza reactive T-cell clone T2.5-5 and a hemin chloride reactive T-cell hybrid SJL-HE-1.1 have revealed a previously undescribedV gene family. We have designated this familyV 15. Southern hybridization analysis has indicated that this family most probably contains only two members, and that these are conserved in each of six mouse strains representing three previously describedV haplotypes:V a ,V b , andV c .  相似文献   

6.
Summary Long-range physical maps of the small multigene family of the malt -amylase genes (-Amy-1) located on the long arms of wheat chromosomes 6A (the -Amy-A1 locus) and 6B (-Amy-B1) were generated by pulsed-field gel electrophoresis analysis. By using three methylation-sensitive rare-cutter restriction endonucleases, NotI, NruI and MluI, and an -Amy-1 cDNA probe and four gene-specific genomic probes from the -Amy-B1 locus, the size of the -Amy-B1 locus was estimated to be about 700 kb and of the -Amy-B1 locus to be about approximately 4300 kb. These two maps indicate clustering of GC-rich and C-methylation-sensitive restriction enzyme recognition sites. At least five regions reminiscent of CpG islands are apparent in -Amy-B1, and three in -Amy-A1. Correlation between recombination frequency and physical distance within the -Amy-B1 locus suggests that 1 cM approximates to 1 Mb in physical distance.  相似文献   

7.
Production of -amylase by a strain of Bacillus amyloliquefaciens was investigated in a cell recycle bioreactor incorporating a membrane filtration module for cell separation. Experimental fermentation studies with the B. amyloliquefaciens strain WA-4 clearly showed that incorporating cell recycling increased -amylase yield and volumetric productivity as compared to conventional continuous fermentation. The effect of operating conditions on -amylase production was difficult to demonstrate experimentally due to the problems of keeping the permeate and bleed rates constant over an extended period of time. Computer simulations were therefore undertaken to support the experimental data, as well as to elucidate the dynamics of -amylase production in the cell recycle bioreactor as compared to conventional chemostat and batch fermentations. Taken together, the simulations and experiments clearly showed that low bleed rate (high recycling ratio) various a high level of -amylase activity. The simulated fermentations revealed that this was especially pronounced at high recycling ratios. Volumetric productivity was maximum at a dilution rate of around 0.4 h–1 and a high recycling ratio. The latter had to exceed 0.75 before volumetric productivity was significantly greater than with conventional chemostat fermentation.List of Symbols a proportionality constant relating the specific growth rate to the logarithm of G (h) - a 1 reaction order with respect to starch concentration - a 2 reaction order with respect to glucose concentration - B bleed rate (h–1) - C starch concentration (g/l) - C 0 starch concentration in the feed (g/l) - D dilution rate (h–1) - D E volumetric productivity (KNU/(mlh)) - e intracellular -amylase concentration (g/g cell mass) - E extracellular -amylase concentration (KNU/ml) - F volumetric flow rate (l/h) - G average number of genome equivalents of DNA per cell - k l intracellular equilibrium constant - k 2 intracellular equilibrium constant - k s Monod saturation constant (g/l) - k 3 excretion rate constant (h–1) - k d first order decay constant (h–1) - k gl rate constant for glucose production - k st rate constant for starch hydrolysis - k t1 proportionality constant for -amylase production (gmRNA/g substrate) - k 1 translation constant (g/(g mRNAh)) - KNU kilo Novo unit - m maintenance coefficient (g substrate/(g cell massh)) - n number of binding sites for the co-repressor on the cytoplasmic repressor - Q repression function K1/K2Q1.0 - R ratio of recycling - R s rate of glucose production (g/lh) - r c rate of starch hydrolysis (g/(lh)) - R eX retention by the filter of the compounds X: starch or -amylase - r intracellular -amylase mRNA concentration (g/g cell mass) - r C volumetric productivity of starch (g/lh) - r E volumetric productivity of intracellular -amylase (KNU/(g cell massh)) - r r volumetric productivity of intracellular mRNA (g/(g cell massh)) - r e volumetric productivity of extracellular -amylase (KNU/(mlh)) - r s volumetric productivity of glucose (g/(lh)) - r X volumetric productivity of cell mass (g/(lh)) - S 0 free reducing sugar concentration in the feed (g/l) - S extracellular concentration of reducing sugar (g/1) - t time (h) - V volume (l) - X cell mass concentration (g/l) - Y yield coefficient (g cell mass/g substrate) - Y E/S yield coefficient (KNU -amylase/g substrate) - Y E total amount of -amylase produced (KNU) - substrate uptake (g substrate/(g cell massh)) - specific growth rate of cell mass (h–1) - d specific death rate of cells (h–1) - m maximum specific growth rate of cell mass (h–1) This study was supported by Bioprocess Engineering Programme of the Nordic Industrial Foundation and the Center for Process Biotechnology, the Technical University of Denmark.  相似文献   

8.
2-Macroglobulin (2M) is a protease inhibitor that has separate binding sites for transforming growth factor- (TGF-) and -amyloid peptide (A), both of which have been identified in the 2M sequence. In the 3D-structure of 2M, TGF- occupies the 2M central cavity, overlapping with the space that can accommodate up to two molecules of protease. As a result, ternary 2M–protease complexes (2 mol protease/mol 2M) have been reported to not bind TGF-. The goal of the present study was to test whether binding of A to 2M is controlled by steric constraints imposed by associated proteases, similarly to TGF-. We confirmed that binary 2M–trypsin complex (1 mol trypsin/mol 2M) binds increased amounts of TGF-1, compared with native 2M, while ternary 2M–trypsin complex binds substantially decreased amounts of TGF-1. By contrast, A-binding to binary and ternary 2M–trypsin complex was equivalent. In both cases, binding was substantially increased compared with the negligible level observed with native 2M. Plasmin is a large protease (Mr ~82,000) that substantially occupies the 2M central cavity; however, 2M–plasmin complex also bound increased amounts of A, compared with native 2M. We conclude that A accesses its binding site, in 2M, from outside the 2M central cavity. The TGF--and A-binding sites are spatially separated not only in the primary sequence of 2M, but also in the 3D-structure.  相似文献   

9.
P. Meffre  F. Le Goffic 《Amino acids》1996,11(3-4):313-328
Summary Ethynyl glycine is a naturally occurring unusual-amino acid. Its known chemical and biological properties are summarized in the first part of this review. The second part is an overview on racemic syntheses of ethynyl glycine and other,-alkynyl-amino acid derivatives, including patent data. These small polyfunctional compounds revealed as being very labile and the synthesis of mainly fully or partially protected forms seemed to have been actually performed. The last part deals with the approaches to the enantioselective synthesis of,-alkynyl-amino acids derivatives, and details the only satisfactory strategy that has led to optically active,-alkynyl-amino acids derivatives up to now.  相似文献   

10.
The regional difference in the carbohydrate components of the ductus epididymis epithelium of a lizard was delineated by means of 13 lectins. Basal cells expressed only N-acetylglucosamine (GlcNAc). Throughout the ductus, the secretory cells showed oligosaccharides with terminal N-acetylneuraminic acid (Neu5Ac)(2,6)galactose (Gal)/N-acetylgalactosamine (GalNAc) and internal mannose (Man) and/or glucose (Glc) in the whole cytoplasm, oligosaccharides terminating in Neu5Ac(2,6)Gal(1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, GalNAc, GlcNAc, and fucose (Fuc) in the supra-nuclear zone, and also glycans terminating in Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal(1,3)GalNAc, Gal (1,4)GlcNAc on the luminal surface. In the caput and corpus regions, the supra-nuclear cytoplasm was characterized by terminal Gal(1,4)GlcNAc and GalNAc, the luminal surface by GalNAc and Gal. The Golgi zone, showing oligosaccharides with terminal Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal (1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, and internal GlcNAc, expressed terminal Gal (1,4)GlcNAc and GalNAc in the caput, and terminal GalNAc in the corpus. The granules showed all the investigated carbohydrates in their peripheral zone except terminal GalNAc and Fuc, whereas internal Man/Glc and terminal Gal were expressed in the central core, and Fuc throughout the ductus, terminal GlcNAc in the caput and corpus, and terminal GalNAc only in the corpus.  相似文献   

11.
Ten previously unreported oligosaccharides have been purified from the urines of human subjects using a combination of gel filtration, ion exchange, and thin-layer chromatographies. Their structures were determined by direct probe mass spectrometry, methylation analysis, and proton NMR spectroscopy of the permethylated oligosaccharide alditols.On the basis of composition, the oligosaccharides could be divided into three groups. Five oligosaccharides containing glycerol were characterized as glucosyl1-1glycerol; glucosyl1-1glycerol; galactosyl1-1glycerol; glucosyl-1-1(fucosyl-1-2)glycerol and/or fucosyl-1-1(glucosyl-1-2)glycerol; and glucosyl-1-1(galactosyl-1-2)glycerol or galactosyl-1-1(glucosyl-1-2)glycerol. Four inositol-containing oligosaccharides were characterized as galactosyl1 (fucosyl1)inositol,N-acetylgalactosaminyl1 (fucosyl1)inositol, fucosyl1-2galactosyl1 (N-acetylgalactosaminyl1)inositol and fucosyl1-2galactosyl1-4-N-acetylglucosaminyl1(N-acetylgalactosaminyl1)inositol. Finally, galactosyl1-3(fucosyl1-2)galactosyl1-6galactosyl1-4(fucosyl1-3)glucose, an oligosaccharide with glucose at its reducing end, was tentatively identified. The significance and possible origins of the carbohydrate structures are discussed.  相似文献   

12.
Summary Corticotropin and melanotropin producing cells were localized in the adenohypophysis of normal Lerots by using antibodies against synthetic corticotropins (anti 1–24 ACTH, anti 17–39 ACTH, anti 25–39 ACTH), and melanotropins (anti MSH, anti MSH). All the anticorticotropin sera stained the same cells both in the anterior lobe and in the intermediate lobe. The anti MSH serum only stained a few cells, exclusively located in the intermediate lobe. These MSH cells were not stained with anticorticotropin antibodies. The anti MSH serum revealed all the cells stained with anticorticotropin and anti MSH sera. Absorption tests showed that the 4–10 heptapeptide common to ACTH and MSH, is not responsible for the immunohistochemical staining. The staining of only some corticotrophs with the anti 4–10 ACTH serum might indicate the presence in these cells of a peptide with an accessible 4–10 site. These results are discussedWe thank A. Pillez for technical assistance (C.N.R.S.). This work was supported by a grant from U.E.R. III Lille 1976Attaché de Recherche INSERM  相似文献   

13.
Full-length cDNAs encoding the - and -subunits and a truncated mutant subunit of the Chlorella sorokiniana NADP-GDH isozymes were constructed and expressed in Escherichia coli cells. The kinetic and thermal stability properties of the resultant homohexamers were examined. The electrophoretic mobility of the recombinant - and -subunits was identical to that of the native subunits as determined by immunoblotting. The homohexamers were purified by anion-exchange and gel-filtration chromatography. The - and -homohexamers that were synthesized in the bacterial cells were shown to have similar Michaelis constants for their substrates as previously shown after synthesis in C. sorokiniana cells (Bascomb and Schmidt, 1987). The homohexamer synthesized in the bacterium was allosteric with respect to NADPH but to a lesser degree than when isolated from the alga. The mutant homohexamer was composed of subunits that were truncated by 40 amino acids at their N-termini. This mutant isozyme was kinetically similar to the larger, anabolic -homohexamer, but it did not display the allosteric response to NADPH shown by the -homohexamer. The three isozymes had significant thermal tolerance and were stable at 50 °C. The temperature optimum for catalytic activity for the - and -homohexamers was 60 °C, and 65 °C for the 40N homohexamer. This study demonstrated that most of the kinetic properties of the Chlorella sorokiniana NADP-GDH isozymes were retained after their synthesis in a heterologous system, and that the distinctive N-terminal domains of these isozymes have dramatic effects on their biochemical characteristics.  相似文献   

14.
Recently, it has been found that plants, including tomato (Lycopersicon esculentum), express the Lewis-a epitope, Gal1,3(Fuc1,4)GlcNAc, on some N-glycans. By searching the EST database, it was possible to identify a tomato cDNA encoding a protein, designated FucTC, of 413 amino acids with homology to plant and mammalian 1,3/4-fucosyltransferases. The cDNA was expressed in Pichia pastoris and the recombinant enzyme was found to transfer fucose from GDP-Fuc (Km 16 M) to lacto-N-tetraose (Gal1,3GlcNAc1,3Gal1,4Glc; Km 80 M) as well as to 1,3- and 1,4-galactosylated N-glycans. It is concluded that FucTC is responsible for the biosynthesis of Lewis-a on N-glycans in tomato.  相似文献   

15.
The basis for the differentiation of l-glycerol-3-phosphate dehydrogenase (-GPDH) into larval and adult isozymes in Drosophila melanogaster was investigated by the correlation of a lack of appearance of each isozyme during development within Drosophila bearing -GPDH null alleles and by the study of a putative conversion factor. Conversion studies indicate the presence of a heat-labile RNase-resistant conversion factor present in crude larval extracts with the ability to convert GPDH-1 to GPDH-2 and GPDH-3 but not vice versa. In addition, null mutations at the Gpdh locus obliterate all isozymatic species of -GPDH in all developmental stages. These observations suggest that all -GPDH isozymes are the product of a single structural gene and that the multiple forms of this enzyme arise during successive developmental stages through an epigenetic modification of the primary Gpdh + polypeptide. Finally, observations are reported which bear on the functional divergence of the -glycerophosphate cycle in the adult and larval stage of development.This investigation was supported in part by NIH Research Grant No. GM-15691 and Genetics Training Grant No. 2 TI GM-685 at the University of North Carolina and by NIH Research Grant No. GM-11546 at North Carolina State University.Paper No. 5054 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.  相似文献   

16.
Summary Isoelectric focusing (pH 4.0–5.0) of serum 2HS-glycoprotein on polyacrylamide gels has been found to be a useful tool in population genetics and forensic science. Using this method, we isolated three common types, 2HS 1-1, 2HS 2-1 and 2HS 2-2, and showed that 2HS types are determined by two autosomal codominant alleles, 2 HS 1 and 2 HS 2. The method is simple, fast and easy to perform. Results of typing for the two alleles, 2 HS 1 and 2 HS 2, are described for a Japanese population sample (n=1003).  相似文献   

17.
Variation of seed -amylase inhibitors was investigated in 1 154 cultivated and 726 non-cultivated (wild and weedy) accessions of the common bean, Phaseolus vulgaris L. Four -amylase inhibitor types were recognized based on the inhibtion by seed extracts of the activities of porcine pancreatic -amylase and larval -amylase and larval -amylase of the Mexican bean weevil, Zabrotes subfasciatus Boheman. Of the 1 880 accessions examined most (1 734) were able to inhibit porcine pancreatic -amylase activity, but were inactive against the Z. subfasciatus larval -amylase; 41 inhibited only the larval -amylase activity, 52 inhibited the activities of the two -amylases, and 53 did not inhibit the activity of either of the -amylases. The four different inhibitor types were designated as AI-1, AI2, AI-3, and AI-0, respectively. These four inhibitor types were identified by the banding patterns of seed glycoproteins in the range of 14–20 kDa by using SDSpolyacrylamide gel electrophoresis. Additionally, four different banding patterns were recognized in accessions with AI-1, and were designated as AI-1a, 1b, 1c, and 1d. Two different patterns of the accessions lacking an -amylase inhibitory activity were identified and designated as AI-0a and AI-0b. The largest diversity for seed -amylase inhibitors was observed in non-cultivated accessions collected from Mexico where all eight inhibitor types were detected. The possible relationships between the variation of seed -amylase inhibitors and bruchid resistance are discussed.  相似文献   

18.
Summary Whole cells of Bacillus subtilis were immobilized in polyacrylamide gel prepared from 5% total acrylamide (85% acrylamide and 15% N,N-methylenebisacrylamide). Production of -amylase by the immobilized whole cells was attempted in a batch system. -Amylase produced by the immobilized whole cells was about three times larger than that produced by washed cells at optimum conditions. The reusability of the immobilized whole cells and washed cells was examined. The activity of -amylase production by washed cells decreased with increasing use cycles. On the other hand, the activity of the immobilized cells increased gradually, and it reched a steady state after seven cycles. -Amylase was produced from a simple reaction medium containing 1% meat extract and 0.05% yeast extract by the immobilized whole cells. The rate of -amylase production by the immobilized whole cells was the same as in submerged cultivation using starch bouillon medium. Growth of B. subtilis in polyacrylamide gel was observed by electron microscopy.  相似文献   

19.
Two forms of -glucosidase (EC 3.2.1.20), designated as I and II, have been isolated from sugarbeet (Beta vulgaris L.) seeds by a procedure including fractionation with ammonium sulfate and ethanol, carboxymethyl-cellulose column chromatography, and preparative disc gel electrophoresis. The two enzymes were homogeneous by polyacrylamide disc gel electrophoresis. Their molecular weights were 98,000 (I) and 60,000 (II). -Glucosidase I readily hydrolyzed maltose, isomaltose, kojibiose, maltotriose, panose, amylose, soluble starch, amylopectin and glycogen. -Glucosidase II also hydrolyzed maltose, kojibiose and maltotriose but hydrolyzed the other substrates only very weakly or not at all. -Glucosidase I hydrolyzed soluble starch at a faster rate than maltose. It produced isomaltose and panose as the main -glucosyltransfer products from maltose, whereas maltotriose was the main product of -glucosidase II. -Glucosidase I hydrolyzed amylose liberating -glucose. The neutral-sugar content was calculated to be 2.7% for -glucosidase I and 8.8% for -glucosidase II. The main neutral sugar was mannose in -glucosidase I, and glucose in -glucosidase II.  相似文献   

20.
We have studied the restriction fragment length polymorphisms (RFLPs) found in the germline T-cell receptor genes of 25 inbred Mus musculus strains and 8 wild Mus species. Included in the inbred mice tested were several strains which spontaneously develop systemic autoimmune disease. Extensive polymorphism was evident for the variable (V) gene segments of the gene family for both the inbred strains and wild mouse species. Changes in the total number of bands hybridizing with probes for V gene segments suggest that members of a V gene segment subfamily are not closely linked, but are interspersed with members of other subfamilies; that expansion and contraction of the multimembered subfamilies may be an important diversifying factor. Our data obtained with gene probes revealed genomic diversity that is much more limited than that seen for the locus. Analysis of inbred mice with probes for the gene locus revealed some RFLPs, but little evidence of expansion or contraction in the numbers of gene segments. Among the autoimmune mice, NZW, NZB, and BXSB/MpJ all display distinctive differences with gene probes. NZW mice have a large deletion of the gene family, which has been reported previously. We found no differences to distinguish the MRL/MpJ lpr/lpr mice from non-autoimmune strains.  相似文献   

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