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1.
    
Summary The production of sex pheromones responsible for the induction of the sexual agglutination ability in the mutants of the mating type locus, mata1, mat1 and mat2, was examined. mata1 cells behaved just like wild-type MATa cells in the production of a pheromone and responsiveness to pheromone. On the other hand, mat1 cells showed neither a nor ability in the production of and the agglutination ability induction by sex pheromones. Cells carrying mat2 secreted a pheromone but not pheromone and showed the ability to inactivate pheromone. However, mat2 cells responded to neither a nor pheromone in the induction of sexual agglutionation ability.  相似文献   

2.
The percentages of the -chain variant Hb G-Philadelphia (Hb G) or 2 68 AsnLys2 were evaluated in 84 adult and 18 newborn heterozygotes. These included members of three families who were studied in more detail by nucleic acid hybridization techniques. The adult heterozygotes fell in two categories, one with a higher proportion of Hb G [46.5±1.0% (SD), N=21] and another with lower values (33.9±3.4%, N=63). Among the newborn heterozygotes, two babies fell in the category with the higher proportion of Hb G while 16 babies gave values between 25 and 34%. Studies of -chain gene organization on the parents of one neonate with a Hb G level of 27% at birth and 37% at 8 months excluded the presence of chromosomes with triplicated -chain genes which could lead to the 0G/ genotype. Rather, these studies on five Hb G heterozygotes from three families confirmed the linkage between Hb G and a specific type of -thalassemia-2 associated with the presence of a 16-kbp Bgl II fragment which most probably carries the G locus since it has been found in 19 Hb G heterozygotes studied to date. The presence of an -thal-2 heterozygosity and three -chain genes (0G/) was confirmed among Hb G heterozygotes with lower proportions of this variant. It is likely that the even lower values found in some newborn could arise through defective assembly of G- dimers. The presence of an -thal-2 homozygosity and two active -chain genes, one on each chromosome (0G/0), was confirmed among heterozygotes with the higher proportion of Hb G. One of each of these categories was present in each of the three families investigated. This type of variability in the number of active -chain genes due to a heterozygosity or a homozygosity for -thalassemia-2 explains the trimodality of Hb S percentages among heterozygotes and the atypical hematological or biosynthetic features among patients with -thalassemia and sickle-cell syndromes.This research was supported by USPHS Research Grants HLB-05168 and HLB-15158 and by designated research funds of the Veterans Administration. This is Contribution No. 0693 of the Department of Cell and Molecular Biology, Medical College of Georgia, Augusta.  相似文献   

3.
Structures of the Asn linked oligosaccharides of quail egg-yolk immunoglobulin (IgY) were determined in this study. Asn linked oligosaccharides were cleaved from IgY by hydrazinolysis and labelled withp-aminobenzoic acid ethyl ester (ABEE) afterN-acetylation. The ABEE labelled oligosaccharides were then fractionated by a combination of Concanavalin A-agarose column chromatography and anion exchange, normal phase and reversed phase HPLC before their structures were determined by sequential exoglycosidase digestion, methylation analysis, HPLC, and 500 MHz1H-NMR spectroscopy. Quail IgY contained only neutral oligosaccharides of the following categories: the glucosylated oligomannose type (0.6%, Glc1-3Glc1-3Man9GlcNAc2; 35.6%, Glc1-3Man7–9GlcNAc2). oligomannose type (15.0%, with the structure Man5–9GlcNAc2) and biantennary complex type with core structures of-Man1-3(-Man1-6)Man1-4GlcNAc1-4GlcNAc (9.9%),-Man1-3(GlcNAc1-4)(-Man1-6)Man1-4GlcNAc1-4GlcNAc (25.1%) and-Man1-3(GlcNAc1-4)(-Man1-6)Man1-4GlcNAc1-4(Fuc1-6)GlcNAc (11.4%). Although never found in mammalian proteins, glucosylated oligosaccharides (Glc1Man7–9GlcNAc2) have been located previously in hen IgY.Abbreviations IgG, IgM, IgA, IgY immunoglobulin G, M, A and Y, respectively - ABEE p-aminobenzoic acid ethyl ester  相似文献   

4.
Summary The anterior latissimus dorsi muscle of the chick is largely composed of slow-tonic fibres but contains a few fast fibres defined by their acid-labile, alkali-stable myofibrillar ATPase activity. These fibres are referred to as fibres. Differing from the slow-tonic ( and ) fibres which are multiply innervated withen grape endings, the (fast) fibres are innervated by typicalen plaque endings. The innervation of thirty-two fibres were studied closely and it was concluded that about a half of the fibres were focally innervated whereas a half were innervated in two distinct loci byen plaque endings. In only one case, a fast fibre with three widely spaceden plaque endings was observed. The mean intersynaptic length was significantly larger on fibres than on and fibres. No variation in the histochemical properties of myofibrillar ATPase was observed either along the entire length of singly and dually innervated fibres, or along and fibres. It is concluded that the three extrafusal fibre types of the anterior latissimus dorsi muscle maintain uniform histochemical characteristics along their length in spite of a possible innervation by several motoneurons.  相似文献   

5.
Novel O-serotypes were revealed among Pseudomonas syringae pv. garcae strains by using a set of mouse monoclonal antibodies specific to the lipopolysaccharide O-polysaccharide. Structural studies showed that the O-polysaccharide of P. syringae pv. garcae NCPPB 2708 is a hitherto unknown linear L-rhamnan lacking strict regularity and having two oligosaccharide repeating units I and II, which differ in the position of substitution in one of the rhamnose residues and have the following structures: I:3)--L Rha (12)-- L Rha (12)--L-Rha-(13)--L Rha (1;II: 2)--L-Rha-(13) -L-Rha-(12)--L-Rha-(13)--L Rha (1.The branched O-polysaccharides of P. syringae pv. garcae ICMP 8047 and NCPPB 588T have the same L-rhamnan backbone with repeating units I and II and a lateral chain of 14)- or 13)-linked residues of 3-acetamido-3,6-dideoxy-D-galactose (D-Fuc3NAc). Several monoclonal antibody epitopes associated with the L-rhamnan backbone or the lateral -D-Fuc3NAc residues were characterized.Translated from Mikrobiologiya, Vol. 73, No. 6, 2004, pp. 777–789.Original Russian Text Copyright © 2004 by Ovod, Zdorovenko, Shashkov, Kocharova, Knirel.  相似文献   

6.
Summary A new and stereoselective method to synthesize hydroxyethylamine and hydroxymethylamide peptide bond isosteres is developed. The key step is the addition of 2-trimethylsilylthiazole to -aminoaldehydes, followed by transformation to -hydroxy--aminoaldehydes. The stereochemistry of the addition can be manipulated by the choice of the nitrogen substitution. The isosteres are easily synthesized via Solid Phase Peptide Synthesis, which rapidly gives the desired pseudopeptides.  相似文献   

7.
Various constructions of human haptoglobin (Hp) cDNA coding either for the complete 2FS precursor protein or only for the subunit have been placed under the control of the PR promoter in the bacterial expression vector pCQV2 (Queen, 1983). In addition to the expected 45,000 dalton polypeptide synthesized after induction of the PR promoter, the complete 2FS constructions constitutively express a smaller polypeptide of 30,000 dalton corresponding to a truncated Hp protein. Computer analysis of the HpcDNA revealed the presence of two strong potential bacterial promoters (2PF and 2PS) located in the duplicated 2FS sequence. Both Hp promoter signals are followed by potential mRNA start sites and ribosome binding sites at a compatible distance from initiation codons. In addition, the Hp2 cDNA sequence, when fused upstream to the cDNA coding for 1-antitrypsin, constitutively promotesin vivo the efficient expression of an hybrid protein specifically recognized by antibodies raised against 1-antitrypsin or haptoglobin.  相似文献   

8.
Translation elongation factor EF-1 became stably associated with potato tuber polysomes at the onset of hypoxia, coincident with a sharp rise in lactate and decrease in tissue pH. This aberrant association of EF-1 with polysomes also occurred when aerobic tuber extracts were acidified in vitro. Upon resumption of protein synthesis, an increase in the steady-state levels of EF-1, and expression of an EF-1/GUS transgene was observed. These results indicate that translational arrest results from to the failure of EF-1 to dissociate from ribosomes during the elongation cycle, and that restoration of protein synthesis is coordinated with expression of EF-1.  相似文献   

9.
In order to study the effect of glycosylation on its biological activities and to develop IL-1 with less deleterious effects, N-acetylneuraminic acid (NeuAc) with C9 spacer was chemically coupled to human recombinant IL-1. NeuAc-coupled IL-1 (NeuAc-IL-1) exhibited reduced activities in vitro and receptor-binding affinities by about ten times compared to IL-1. In this study, we examined a variety of IL-1 activities in vivo. NeuAc-IL-1 exhibited a marked reduction in the activity to up-regulate serum IL-6, moderate reduction in the activities to up-regulate serum amyloid A and NOx. However, it exhibited comparable activities as IL-1 to down-regulate serum glucose and to improve the recovery of peripheral white blood cells from myelosuppression in 5-fluorouracil-treated mice. In addition, tissue level of NeuAc-IL-1 was high compared to IL-1. These results indicate that coupling with NeuAc enabled us to develop neo-IL-1 with selective activities in vivo and enhanced tissue level.  相似文献   

10.
Mild cerebral anoxic/ischemic/stress insults promote tolerance and thereby protect the brain from subsequent lethal anoxic/ischemic insults. We examined whether specific activation of PKC , , , or isoforms is associated with ischemic preconditioning (IPC) in rat brain. IPC was produced by a 2-minute global cerebral ischemia. Membrane and cytosolic fractions of the hippocampi were immunoblotted using specific antibodies for PKC, , , and . PKC showed a significant translocation to the membrane fraction from 30 min to 4 h and PKC at 4 h following IPC. In contrast, the membrane/cytosol ratio of PKC showed a tendency to decrease at 30 min and 8 h, and the membrane/cytosol ratio of PKC was significantly decreased from 30 min to 24 h following IPC. These findings indicate PKC isoform-specific membrane translocations in the hippocampus after brief global brain ischemia and suggest that activation of PKC and PKC may be associated with IPC-induced tolerance in the rat hippocampus.  相似文献   

11.
Shoot tip and single node explants from young shoots of 1-year old flowering plants of Rauwolfia micrantha Hook. f. were cultured on Murashige & Skoog (MS) medium variously supplemented with 6-benzyladenine (BA) and -naphthaleneacetic acid (NAA). A combination of 13.2 M BA and 2.68 M NAA induced high frequency (77%) formation of up to 3 shoots from each node in 8 weeks. The regeneration of shoot tips from the field-grown plants and in vitro shoots placed horizontally differed. Repeated subculturing of the shoot tips and single nodes at 6-week intervals for over a year in combination of 4.4 M BA and 0.27 M NAA enabled mass multiplication of shoots without any evidence of decline. Rooting of the excised shoots on medium containing 2.6 M NAA was preceded by callus formation. The rooted plants were removed off the callus, hardened off and 80% established in pots. Micropropagated plants displayed uniform morphological, growth, flowering, fruiting and seed germination characteristics.Abbreviations BA 6-benzyladenie - IAA indole-3-acetic acid - IBA indole-3-butyrie acid - 2-ip 2-isopentenyladenine - MS Murashige & Skoog (1962) - NAA -naphthaleneacetic acid  相似文献   

12.
The distribution of A- and B-crystallin in the developing lens of human (Carnegie stages 13 to 23) and rat embryos (embryonic days E11 to 18) was examined immunohistochemically. In a human embryo at stage 13, the lens placode was already immunoreactive to B-crystallin, but not to A-crystallin. At stage 15, the lens vesicle was intensely immunoreactive both to A- and B-crystallin. From stages 16 to 23, the lens epithelial cells and fiber cells were immunoreactive to A- and B-crystallin. In rat embryos, A-crystallin appeared in the lens pit at E12, and B-crystallin appeared in the elongating lens fiber cells at E14. From E15 to E18, the lens epithelial cells and fiber cells were immunoreactive to A-crystallin. The lens fiber cells were also immunoreactive to B-crystallin, but the epithelial cells were not. These findings suggest that B-crystallin appears earlier than A-crystallin in the human lens, but at a later period than A-crystallin in the rat lens. B-Crystallin was not detected in the epithelial cells of the rat lens, but was perisistently present in the epithelial cells of the human lens.  相似文献   

13.
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   

14.
In the presence of the modifier protein -lactalbumin, bovine milk galactosyltransferase transfers galactose to glucose forming lactose instead of transferring toN-acetylglucosamine formingN-acetyllactosamine. At low concentrations of -lact-albumin, the lactosamine synthase activity is stimulated by -lactalbumin and decreases when the lactose synthase activity develops along a sigmoidal curve. The observation suggests that different interactions between -lactalbumin and enzyme were responsible for the modulating effect of the -lactalbumin in the lactose and lactosamine synthase reactions.To study the nature of the protein-protein interactions, -lactalbumin was both modified and cleaved chemically. Reduction and alkylation with iodoacetic acid, iodoacetamide or 4-vinylpyridine abolished the ability of the -lactalbumin to induce lactose synthase activity but stimulated lactosamine synthase activity 7-to 12-fold.A peptide fragment corresponding to residues 26–60 of -lactalbumin isolated from a 2-(2-nitrophenylsulphenyl)-3-methyl-3-bromo-indolene (BNPS-skatole) fragmentation of the molecule was active in the lactosamine but not lactose synthase reaction. We concluded that, whereas lactose synthase required -lactalbumin, in the native conformation, lactosamine synthase activity was stimulated by a linear sequence of amino acids in peptide 26–60.Abbreviations MES 4-N-morpholinoethanesulfonic acid - TRIS 2-amino-2-(hydroxymethyl)-1,3-propanediol - UDP-Gal uridinediphosphogalactose - BNPS-skatole 2-(2-nitrophenylsulphenyl)-3-methyl-3-bromo-indolene - EDTA ethylene diamine tetra acetic acid  相似文献   

15.
The aerobic nitrogen-fixing unicellular cyanobacteriumSynechococcus RF-1 (pcc 8801) contains numerous irregular polyglucan granules ranging in size from 0.1 to 0.4 m. These morphologically unusual polyglucan granules are not found in the sheathed nitrogen-fixing unicellular cyanobacteriumGloeothece RF-6 (pcc 8803). Two forms of -amylase, ethyleneglycolbis-(-aminoethyl ether)-N,N,N,N-tetraacetic acid (EGTA)-sensitive and EGTA-insensitive, were found in theSynechococcus RF-1. In addition to their EGTA sensitivity, the two forms of -amylase also differed in their reactive pH range and in their zymogram disc gel electrophoresis. Each form of -amylase was stable and constant in concentration through a diurnal light/dark cycle.  相似文献   

16.
    
Summary A mutant of Escherichia coli, in which signal peptidase I synthesis can be regulated, was constructed. The mutant was used to study the effects of signal peptidase I limitation on the synthesis and efficiency of processing of two proteins: the periplasmic E. coli TEM--lactamase and Bacillus licheniformis -amylase, which also accumulates in the periplasm of E. coli. Signal peptidase I limitation resulted in reduced rates of processing of pre--lactamase and in strong inhibition of synthesis of -amulase. The data suggest that -lactamase is processed post-translationally and that an intimate relationship exists between the synthesis and processing of -amylase.  相似文献   

17.
Summary With growing cells of a Nocardia sp., isolated from soil, the degradation of 5-pregnene-3, 20-diol into 3-[5-oxo-7a-methyl-1 (1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid was investigated. The results show that iron is essential for production of the perhydroindanpropionic acid, that this production is greatly enhanced by the presence of calcium and that it is maximal in the pH range 7.0–7.5.Abbreviations used in the text PD 5-pregnene-3, 20-diol (pregnendiol) - PDSA 3-[5-oxo-7a-methyl-1(1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid (pregnendiol-secoacid) - PSA 3-[5-oxo-7a-methyl-1-acetyl-3a-perhydroindane-4]-propionic acid (progesterone-secoacid) - EDTA Ethylendiamintetracetic acid - DMSO Dimethylsulfoxide  相似文献   

18.
In this study we investigated the effect of the cytokines human granulocyte/macrophage-colony-stimulating Factor (hGM-CSF) and interferon (IFN) on human Kupffer-cell-mediated cytotoxicity against the SW948 coloncarcinoma cell line. Kupffer cells were isolated from small liver wedge biopsies, taken from 14 patient who had had abdominal surgery for colon carcinoma or partial hepatectomy. The cells were incubated with hGM-CSF (100 ng/ml), or with IFN (100 U/ml) or with their combination and the perecentage cytotoxicity was determined using a recently described modified assay. Additional experiments were performed with tumour-necrosis-factor-(TNF)-sensitive U937 cells as target. The TNF secretion of Kupffer cells was measured and we evaluated the effect of TNF on colon tumour targets. We performed human-Kupffer cell-mediated cytotoxicity blocking experiments with anti-TNF and used paraformaldehydefixed Kupffer cells to demonstrate lysis of TNF-sensitive WEHI-164 cells and of SW948 cells. The overall cytotoxicity against SW948 caused by unactivated Kupffer cells (n=14), and by Kupffer cells activated with hGM-CSF (n=14), IFN (n=6) or their combination (n=6) was respectively: 19.5±2.6%, 25.3±2.9% 41±9.4% and 45.6±8% at E/T=1 and 28.2±2.9%, 35.6±3.2%, 55.6±9.7% and 62.8% at E/T=5. All differences were statistically significant (P<0.05). No growth-promoting activity by hGM-CSF on the SW948 tumour cells was observed. U937 cells were highly susceptible to Kupffer-cell-mediated cytotoxicity. The TNF secretion by human Kupffer cells increased in parallel to their cytotoxicity after incubation with these cytokines. Soluble TNF had only a slight anti-proliferative effect on SW948 cells, while specific anti-TNF blocked Kupffer cell cytotoxicity by up to 80%. Finally, paraformaldehyde-fixed Kupffer cells were able to lyse WEHI-164 and SW948 cells. This indicates that expression of cell-associated TNF is the main cytolytic mechanism of human-Kupffer-cell-mediated cytotoxicity. The implications for the use of hGM-CSF and IFN in vivo are discussed.  相似文献   

19.
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   

20.
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   

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