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1.
Summary Southern blotting and DNA sequencing after polymerase chain reaction (PCR) amplification provide evidence for the frequent occurrence (in 7 out of 24 chromosomes) of a short conversion GA in the 3 end of the human fetal A globin gene. This short conversion is characterized by the presence, 3 nucleotides downstream from the termination codon of the A gene, of the TCAC sequence that is normally present at the equivalent position at the 3 end of the G gene; it is therefore identical to a conversion already described. Interestingly, we have found that this conversion is associated with the presence of theHindIII polymorphic restriction site in the A IVS2, occuppying an equivalent position in both the G and A genes. Our observations strengthen the hypothesis that the presence of the HindIII polymorphic restriction site in A IVS2 and the presence of the sequence TCAC at the 3 end of the A gene might be the result of a single conversion event.  相似文献   

2.
Summary The combined use of proteolytic digestion and lactoperoxidase catalyzed labelling with [125I] applied to membrane-bound or soluble pure F1-ATPase from Micrococcus lysodeikticus has allowed us to establish the topography of its , , and subunits within the protein molecule and with respect to the plane of the membrane.The subunit is most externally located to the membrane bilayer looking towards the cytoplasmic face, a position consistent with its proposed catalytic role. The and subunits lie in an intermediate layer between the subunits and the membrane, in which the subunit occupies a central position within the F1-ATPase molecule in contact with the subunit. The subunit appears to be tightly bound to the F0 component of the ATPase complex, probably buried in the membrane bilayer. A molecular arrangement of M. lysodeikticus ATPase is proposed that, taking into account the subunit stoichiometry 3 3 2 2 (MW 420 000), accommodates the role assigned to each subunit and most, if not all, the known properties of this bacterial energy-transducing protein.  相似文献   

3.
Summary Five monoclonal antibodies raised against an enriched C hordein fraction have been characterized in detail and were found to be specific for the members of the sulphur-rich hordein family. Two antibodies specific for B hordein polypeptides were identified, one of which reacted predominantly with CNBr cleavage class III polypeptides. 1 hordein was recognized by two antibodies, of which one also reacted with 2 hordein and several members of the CNBr cleavage class II B hordein polypeptides. One antibody recognized 3 hordein but cross-reacted at higher antibody concentration with almost all of the B and C hordein polypeptides. The specificity of the monoclonal antibodies was confirmed by Western blotting of one- or two-dimensionally separated hordein from the B hordein-deficient mutant hor2ca and its wild-type Carlsberg II and the 3 hordein-deficient genotype Nevsky. The identification of the hordein-specific monoclonal antibodies was further supported by immune precipitation of in-vitro transcribed and translated 2 hordein, and hor2ca and Carlsberg II mRNA translation products. The monoclonal antibodies were used to screen for mutants in hordein synthesis. Two mutants, one deficient in 1 hordein synthesis and a second in 2 or closely related B hordein polypeptides were identified. A model is proposed for the evolution of the sulphur-rich hordein loci Hor5 and Hor2.  相似文献   

4.
The receptor with high affinity for immunoglobulin E (FcERI) is a key molecule in triggering the allergic reaction. It is tetrameric complex of one subunit, one subunit, and two disulfide-linked subunits. This receptor is present exclusively on mast cells and basophils. Molecules identical to the subunit of FcRI also form cell surface complex with other Fc receptors such as mouse FcRIIa in macrophages and most probably with human FcRIII (CD16) in natural killer (NK) cells. Here we show by in situ hybridization that the human genes for the (FCER1A) and subunits (FCER1 G) of FcERI and the gene for FcRIII (FCGR3, CD16) are located on human chromosome band 1823.  相似文献   

5.
-NGF is an inactive serine protease that is associated in the mouse submandibular gland with a closely related serine protease, -NGF, and the neurotrophic factor, -NGF. The heterogeneity of purified -NGF has been examined by DEAE-cellulose chromatography and SDS polyacrylamide gel electrophoresis. A possible explanation for the observed heterogeneity is presented. Antibodies have been prepared against -NGF and purified by affinity chromatography so that they do not cross-react with -NGF. This antibody preparation recognizes two very similar proteins in male mouse submandibular gland RNA-directed cell-free translation mixtures. The expression of only one of these forms is regulated by testosterone. Oligonucleotide probes specific for each of the three NGF subunits have been prepared and used for Northern blot analysis of RNA from the mouse submandibular gland. The three subunits were found to be coordinately expressed and each were 30-fold more abundant in male than in female glands.Abbreviations used NGF nerve growth factor - -, -, and -NGF -, -, and -subunits of mouse 7S NGF - PBS phosphate buffered saline - DTT dithiothreitol - PPO 2,5-Diphenyloxazole - DMSO dimethylsulfoxide - HEPES N-2-Hydroxyethylpiperazine-N-2-ethanesulfonic acid - SSC 0.15M NaCl, 15 mM sodium citrate Supported by USPHS research grant NS19964. This paper is respectfully dedicated to Profs. Eric M. Shooter and Silvio Varon in recognition of their many contributions to our understanding of the structure and function of nerve growth factor.  相似文献   

6.
Phosphorylase kinase (PhK) from skeletal muscle is a structurally complex, highly regulated, hexadecameric enzyme of subunit composition ()4. Previous studies have revealed that the activity of its catalytic subunit is controlled by alterations in quaternary structure initiated at allosteric and covalent modification sites on PhK's three regulatory subunits; however, changes in the conformation of the holoenzyme initiated by the catalytic subunit have been more difficult to document. In this study a monoclonal antibody (mAb 79) has been generated against isolated subunit and used as a conformational probe of that subunit. The epitope recognized by this antibody is within the catalytic core of the subunit, between residues 100 and 240, and monovalent fragments of the antibody inhibit the catalytic activity of the holoenzyme, the -calmodulin binary complex, and the free subunit. Activation of PhK by a variety of mechanisms known or thought to act through its regulatory subunits (phosphorylation, ADP binding, or alkaline pH) increased the binding of the holoenzyme to immobilized mAb 79, indicating that activation by any of these distinct mechanisms involves repositioning of the portion of the catalytic domain of the subunit containing the epitope for mAb 79. The activating ligand Mg2+ also stimulated the binding of the PhK holoenzyme to immobilized mAb 79, as well as the binding of mAb 79 to immobilized subunit. Thus, Mg2+ increases the accessibility of the mAb 79 epitope in both the isolated subunit and in the holoenzyme. Our results suggest that previously reported influences of Mg2+ on the quaternary structure of the PhK holoenzyme are directly mediated by the subunit.  相似文献   

7.
Summary The transfer properties of the optical system in the arthropod compound eye are determined by the interommatidial angle , influencing the resolving power, and by the width of the visual fields of single ommatidia , influencing the response at high spatial frequencies of brightness distributions in the object space. The energy transfer/ receptor is proportional to ( )2 and decreases with in-inreasing approximation of the perfect-imaging condition: gD 0; 0. However, a value > 0 has to be maintained in order to overcome the threshold of nervous excitation at a certain minimum-brightness level. Theoretical treatment yields /=0.62 to 0.88 as the corresponding optimum-imaging relation. The actual ratio can be derived from measurements of the optomotor reactions to the movement of periodic brightness patterns. The approximate value 0.76 is obtained from the fruitfly Drosophila with normal and mutant eye pigmentation. As a result, the parameters of this imaging system are found to be established in a way that enables optimum performance at sufficient illumination. An dieser Stelle möchte ich Dr. W. Reichardt für sein eingehendes Interesse und manche anregende Diskussion über die Sehvorgänge im Komplexauge meinen Dank sagen. Dr. K. Kirschfeld verdanke ich ebenfalls wertvolle Hinweise. Herrn E. Freiberg bin ich für die Anfertigung der Abbildungen sehr verbunden.  相似文献   

8.
A simple and rapid method, using only two chromatographic steps, is described for the purification and preparation of enolase isoenzymes from human and beef brain extracts. In the first step, a crude enolase was obtained by chromatography on Q-Sepharose Fast Flow column. The crude fraction was then purified by high performance anion exchange chromatography on a Mono-Q column. enolase obtained in this manner was shown to be homogeneous by two dimensional polyacrylamide gel electrophoresis and by high performance gel permeation chromatography. The yield of enolase by this method was 7–8 mg of pure enzyme per 100 g of brain.  相似文献   

9.
Bacteria, yeasts, and molds which grew in a medium containing a synthetic lignin — a dehydrogenation polymer (DHP) of coniferyl alcohol — as a sole carbon source, were isolated from soil. One fungus, Fusarium solani M-13-1, was found to degrade the DHP most vigorously among the isolated organisms. It was shake-cultured in a medium containing dehydrodiconiferyl alcohol (DHCA) (I), an important lignin model compound, and the following six metabolic products were isolated and identified: 1) Phenylcoumaran--aldehydic (II) and -carboxylic compounds, 2) phenylcoumaran--aldehydic compound (IV), formed by release of a 2-carbon fragment from the phenylcoumaran--carboxylic compound, 3) 5-acetylvanillyl alcohol (V), formed by cleavage of the coumaran ring and reduction of the -aldehyde group, 4) 5-carboxyvanillyl alcohol (VI), formed by subsequent oxidation of the acetyl group, and 5) the -ether of DHCA (VII), considered to be a by-product. A degradation pathway for DHCA was proposed on the basis of these metabolic products.Non-Standard Abbreviations DHP dehydrogenation polymer - DHCA dehydrodiconiferyl alcohol - DDQ dichlorodicyano-p-benzoquinone - DDHQ dichlorodicyano-p-hydroquinone - Ar aromatic - TLC thin layer chromatography - GC-MS gas chromatography-mass spectrometry  相似文献   

10.
Soluble receptors for hormones and cytokines have beendescribed. They can serve as natural blockers of theirrespective ligands. The natural soluble interferongamma receptor (sIFNR) has been isolated andcharacterized only in urine. Chromatography of human(hu) plasma from rheumatoid arthritis (RA) patientsand controls on immobilized hu IFN orantibodies against IFN R chainpermitted us to isolate the sIFNR. Thereceptor isolated from one control is a protein witha molecular weight between 60-67 kDa depending on thepresence of reducing agents. We detected asignificantly higher level of plasma sIFNR inpatients with rheumatoid arthritis than in apparentlyhealthy subjects.  相似文献   

11.
Summary Plasma membranes were prepared from soybean hypocotyls and roots by aqueous two-phase partitioning and subsequent free-flow electrophoresis. The highly purified plasma membranes bound [35S]GTPS with a relatively high affinity (Kd10nM). The binding was saturable and specific as it was indicated by the displacement of bound [35S]GTPS by unlabeled GTPS and GTP, but not by ATPS, ATP, UTP or CTP. ITP was intermediate in its ability to displace [35S]GTPS. When soybean plasma membrane proteins were separated by SDS-PAGE and displayed by autoradiography, two major [35S]GTPS binding proteins were revealed with apparent molecular weights of 24 and 28 kDa. Results with plasma membranes from soybean hypocotyls and roots were similar but differed from those with plasma membranes prepared from rat liver and adipocytes where only a single major [35S]GTPS binding activity with a molecular weight of 28 kDa was observed.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - G protein hetero-trimeric GTP binding protein with , , subunits - Gn protein GTP binding protein detected on nitrocellulose blots - GTPS guanosine 5-[-thio]triphosphate - IAA 3-indoleacetic acid - SDS-PAGE sodium dodecylsulfate-polyacrylamide gel electrophoresis  相似文献   

12.
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  相似文献   

13.
Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of 1H-1H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -3, 3-3, 2-2, 2-2, and 3-3 (2.3 Å) are shorter than those in the pairs -2, 2-3, 3-2, 2-3, and 3-2 (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the 3-2 and 2-3 spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -2, 2-3, and 3-2 vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.  相似文献   

14.
Summary A comparative study of the antitumor effect of murine recombinant interferon() Mu-rIFN() and murine recombinant interferon() Mu-rIFN() on B16-F10 melanoma was conducted. Administration of Mu-rIFN() i.p. into C57BL/6 mice on days 1 to 7 produced a higher suppressive effect than Mu-rIFN() both on the growth of s.c. implanted tumor and on the formation of artificial pulmonary metastasis. Pharmacokinetic study of Mu-rIFN() demonstrated that high plasma levels were retained for a long time. In clonogenic assay, Mu-rIFN() at 1000 units/ml showed about 80% inhibition of colonies of B16-F10 melanoma. However, Mu-rIFN() hardly inhibited the colonies, even at 1000 units/ml. Augmentation of natural killer (NK) cytotoxicity was much greater with Mu-rIFN() than Mu-rIFN(), whereas Mu-rIFN() enhanced the cytotoxicity of peritoneal macrophages more strongly than Mu-rIFN(). Injection of Mu-rIFN() i.p. 1 day before tumor challenge also inhibited the formation of pulmonary metastasis of B16-F10 melanoma. However, pretreatment of mice with carrageenan significantly suppressed the inhibitory effect of Mu-rIFN(). From these results, it is suggested that the inhibitory effect of Mu-rIFN() on the tumor growth and metastases of B16-F10 melanoma is mediated partly by direct antitumor effect and partly by the activation of macrophages, and that the augmentation of NK activity contributes mainly to the antitumor effect of Mu-rIFN().  相似文献   

15.
Summary A survey of hemoglobinopathies in northern Sardinia revealed a high frequency (0.3%) of carriers of a hematologic condition characterized by increased expression of fetal hemoglobin during adult life (hereditary persistence of fetal hemoglobin or HPFH). In spite of a normal hematologic phenotype, the heterozygous carriers for this condition display about 12% HbF, almost exclusively of the A type; compound heterozygotes with -thalassemia have 20%–26% HbF and run a very mild clinical course. The sequence analysis of the cloned A gene linked to the HPFH determinant revealed the presence of a GA substitution at position-117 of the A- gene promoter; the same mutation occurs also in Greek HPFH, although associated with different restriction polymorphisms. Another hereditary condition characterized by increased HbF (2 A2) level and a mild thalassemic phenotype in Sardinia is associated with the-196 CT substitution in the A-globin gene promoter (Sardinian -thalassemia). Population studies using oligonucleotides complementary both to the-117 GA and-196 CT mutations and the corresponding normal sequences confirm the presence of these mutations only in HPFH and -thalassemia chromosomes and exclude these changes being common DNA polymorphisms.  相似文献   

16.
Summary Changes in the -butyrolactone and pantolactone contents in yeast cells and musts during fermentation and subsequent flor veil formation of Sherry wines were studied. Saccharomyces cerevisiae race cerevisiae, S. cerevisiae race bayanus and S. cerevisiae race capensis were used. During the alcoholic fermentation (first 31 days), -butyrolactone contents in musts and yeast cells were similar for the three yeast races tested. In this period, pantolactone was excreted to the must by bayanus and capensis races, and it was not detected in cerevisiae race cells. During flor veil formation (31 to 134 days), bayanus and capensis races yield higher -butyrolactone and pantolactone contents than cerevisiae race in the wines. In the final wines, pantolactone contents were always lower than those of -butyrolactone.  相似文献   

17.
Summary Egg deposition behaviors are analyzed from time-lapse recordings during which spontaneous discharges of the neuroendocrine bag cells are recorded with chronically implanted cuff electrodes. In the laboratory,Aplysia brasiliana normally deposit long egg cordons on the substrate in a characteristic figure 8 pattern similar to the configuration of egg masses observed in the natural environment. The overt behaviors associated with egg deposition are rhythmic head movements consisting of three components that overlap with characteristic relative latencies: up-and-down undulations, side-to-side weaves and in-and-out tamps. The characteristics of the three behaviors and their time courses relative to the appearance of eggs on the substrate suggest that undulations prepare the substrate, weaves distribute the egg cordon and tamps attach the cordon to the substrate. The same rhythmic head movements are also elicited by injections of homogenized abdominal ganglia (HAG) containing bag cell clusters, with comparable relative latencies and maximum frequencies but for shorter total durations. The overt behaviors begin earlier for normal than for triggered egg laying, often before the spontaneous release of bag cell hormones. This suggests that the head oscillations in intact animals are not normally initiated by bag cell activity. The mean latency to the appearance of the egg cordon on the substrate is the same (about 34 min) following either HAG injections or spontaneous bag cell discharges, confirming previous suggestions that the bag cell discharge triggers ovulation. Furthermore, the head movements appear to terminate at the same time following release or injection of hormone. The accompanying paper demonstrates that the full expression of the behavioral effects of bag cell injections depend upon normal movement of eggs in the reproductive tract.Abbreviations CPG central pattern generator - ELH egg laying hormone - HAG homogenized abdominal ganglia  相似文献   

18.
We investigated the influence of the combined use of sizofiran, a-1,3-glucan and a recombinant interferon- (rIFN-) upon biological activities of peritoneal macrophages (M). The number of peritoneal M and the production of cytokines (interleukin-1, interferon- and tumor necrosis factor) was increased by the combined treatment. Fully activated peritoneal M based on the increased number of elongated pseudopods were observed by electromicroscope. Sizofiran seems to assure a sufficient supply of M to kill tumor cells in the peritoneal cavity and co-administered rIFN- seems to directly stimulate the accumulated M in addition to its direct cytotoxicity against tumor cells. This combination therapy may be a step to the prevention of the recurrence of gynecological malignancies including ovarian cancer, after a negative second-look laparotomy.Abbreviations rIFN- recombinant interferon- - IL-1 interleukin-1 - TNF tumor necrosis factor - SLL second look laparotomy  相似文献   

19.
Summary The -glucuronidase staining characteristics of isolated T cell populations and the T and T enriched fractions derived of them were studied. T lymphocytes were obtained from purified T lymphocytes by ox-IgG rosette sedimentation. The rosette-forming cells in the pellet were referred to as T lymphocytes, whereas the lymphocytes in the interface were referred to as T depleted or T lymphocytes. B cells were studied on rosetted mononuclear cells with either mouse erythrocytes or with Staphylococcus Aureus (Cowan I) bacteria, after a preceeding polyvalent anti-human Ig treatment of the cells. While B cells showed mostly no reactivity, T and T cells were respectively characterised by a dot-like and granular pattern of reactivity. These findings are in agreement with those observed by others after -naphthyl-acetate esterase or acid phosphatase staining. Within the T lymphocyte fraction, the T non-, non lymphocytes seemed to have a granular pattern of reactivity. The same staining pattern was found in non-B, non-T lymphocytes.  相似文献   

20.
Summary The expression of the monocyte membrane glycoprotein CD14 was measured and related to the serum interferon (IFN) concentration in thirteen patients with disseminated cancer during treatment with human recombinant interferon (rIFN). The drug was administered by continuous subcutaneous infusion using an escalating dose schedule, starting at 50 µg/day or 100 µg/day and increasing weekly up to 600 µg/day, if tolerated. Treatment was continued at a mean maximal tolerated dose of 200 µg/day for a median duration of 43 days. Serum IFN concentration and monocyte CD14 antigen expression (immunofluorescence with the monoclonal antibody LeuM3 and fluorescence-activated cell sorting analysis) were determined weekly. The serum IFN concentration was positively correlated with the rIFN dose (P <0.05). Therapy induced a dose-dependant enhancement of CD14 antigen expression. The increase in mean CD14 fluorescence intensity was on average 60% after 3 weeks of treatment at a mean dose of 220 µg rIFN/day and was reversed after withdrawal of therapy. Patients with a rapidly rising serum IFN concentration (starting dose 100 µg/day) showed a smaller increment in CD14 fluorescence intensity than those with slowly rising serum IFN levels (starting dose 50 µg/day). Since rIFN is known to down-regulate CD14 antigen expression in vitro, monocytes from patients off therapy and from healthy volunteers were cultured with this cytokine. A similar decrease of CD14 fluorescence was observed in both groups. In patients several factors, such as IFN concentration, duration of drug effect and type of serum, were evaluated and could not explain the discrepant in vivo and in vitro findings. In conclusion, the monocyte marker CD14 was found to be differentially regulated by rIFN in vivo and in vitro. In vivo, secondary mediators, induced by rIFN and acting on a constantly renewed cell population, may contribute to the enhanced CD14 expression.  相似文献   

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