The present work describes a very simple technique for the isolation within 2-3 hr of inactive phosphoenolpyruvate carboxylase protein starting from a crude extract of Sorghum leaves by using an immunoadsorbent column prepared with a glutaraldehyde- activated gel. The conditions for the total elution of the enzyme protein are optimized. For quantitative determinations cyanogen bromide-activated gels should be avoided as the release of fixed immunoglobulin G (IgG) has been observed during washing with the acidic buffer needed to elute the enzyme. In that respect, glutaraldehyde-activated gel does not lose antibodies and consequently gives accurate results. 相似文献
Summary Four hematopoietic cell lines (CCRF-CEM, HSB-2, MOLT-4, and RPMI-8402), derived from acute lymphoblastic leukemia and expressing
T-cell surface markers (T-HCL), were studied with two specific anti-T-cell sera. The sera were raised in rabbits against human
thymocytes (anti-HTY) and against T-cells cultured in the presence of conditioned medium derived from lymphocytes stimulated
with PHA (anti-CTC). Both sera were absorbed to obtain a T-cell specific pattern of reaction and were further absorbed with
normal peripheral blood lymphocytes or with each of the four T-HCL. The anti-HTY sera absorbed with CEM, 8402, and HSB-2 still
reacted with MOLT-4. A similar pattern of reactivity was found only with the anti-CTC absorbed with 8402, whereas, after absorptions
with the other cell lines, this antiserum was unreactive against MOLT-4. After absorption with normal peripheral blood lymphocytes,
anti-HTY still reacted with thymocytes and MOLT-4 but was negative on CTC. In contrast, anti-CTC absorbed with peripheral
blood lymphocytes (PBL) was negative on thymocytes and MOLT-4 but still reacted against CTC. Our data confirm the existence
of a T-cell antigen (probably an early T-cell differentiation antigen) shared between thymus and MOLT-4. This antigen is not
expressed on CTC, although these cells express an antigenic pattern more complex than PBL. Antisera to CTC represents a source
of anti-T-cell sera free of contamination with antibodies to early thymus-related antigens but containing other T-cell-related
specificities.
Supported in part by Naval Medical Research and Development Command, Research Task No. ZF51.524.013.1025, and National Cancer
Institute Contract No. Y01-CB-00319. The opinions and assertions contained herein are the private ones of the writers and
are not to be construed as official or reflecting the views of the Navy Department or the naval service at large. The experiments
reported herein were conducted according to the principles set forth in the current edition of the “Guide for the Care and
Use of Laboratory Animals,” Institute of Laboratory Animal Resources, National Research Council. 相似文献
The structure of the capsular polysaccharide from Klebsiella K26 has been determined by using the techniques of methylation, periodate oxidation, partial hydrolysis, and β-elimination. N.m.r. spectroscopy (1H and 13C) was used to establish the nature of the anomeric linkages and to identify oligosaccharides obtained by the different degradative techniques employed.The polysaccharide is comprised of repeating units of the heptasaccharide shown. 相似文献
The fading of postpartum maternal interest for the neonate (sensitive period) in ewes separated from their young at lambing is delayed when parturition is induced with 20 mg of estradiol benzoate (EB). An experiment was carried out to investigate the role of prolactin in this phenomenon. The sensitive period was studied in three groups of parturient ewes. In all groups lambs were removed at birth and reintroduced to their mothers 24 hr later. Maternal acceptance was tested at this time. In group 1 (dexamethasone D), ewes were induced to lamb with dexamethasone (15 mg im). In group 2 (EB), ewes were treated with 20 mg of estradiol benzoate (im). In group 3 (EB + CB 154) ewes received 20 mg of EB as in group 2 and 1 mg of CB 154 (sc) every 12 hr to prevent the enhanced secretion of prolactin which normally occurs after EB injection. The concentration of prolactin was highest in group 2 (EB), lowest in group 3 (EB + CB), and intermediate in group 1 (D) (p ? 0.001 between groups). By contrast, the proportion of ewes showing maternal behavior was similar in groups 2 and 3 ( and ), both of which differed from group 1 (). It is concluded that the lengthening of the sensitive period for establishing maternal behavior in sheep following EB induced parturition is not related with high levels of prolactin in the peripheral circulation. 相似文献
The formation of complexes between human trypsinogens and the basic pancreatic trypsin inhibitor is demonstrated by using affinity chromatography on Sepharose coupled to basic pancreatic trypsin inhibitor. This interaction indicates the pre-existence of the active site in human trypsinogens. This active site induces the proteolytic activity of the two zymogens which activate spontaneously at pH 5.6 and pH 8.0 before and after affinity chromatography. The effect of affinity-chromatography on trypsinogen spontaneous activation is not the same on trypsinogens 1 and 2. A striking difference appears between the activation of the two trypsinogens. In all cases, trypsinogen 1 autoactivates more rapidly than trypsinogen 2, except at pH 5.6 in the presence of 10 mM Ca2+, which inhibits the autoactivation of trypsinogen 1. The effect of inherent proteolytic activity of human trypsinogens is discussed in relation to pathological conditions of enterokinase deficiency and acute pancreatitis. 相似文献
Cytochromes c3 of different strains of sulfatereducing bacteria have been purified and tested for their capacity to reduce colloidal sulfur to hydrogen sulfide. The results are in good agreement with the activities reported for the whole cells. Cytochrome c3 is the sulfur reductase of some strains of sulfate-reducing bacteria such as Desulfovibrio desulfuricans Norway 4 and sulfate-reducing bacterium strain 9974 from which the sulfur reductase activity can be purified with the cytochrome c3. In contrast, Desulfovibrio vulgaris Hildenborough cytochrome c3 is inhibited by the product of the reaction namely hydrogen sulfide. Chloramphenicol has no effect on the sulfur reductase activity of D. desulfuricans Norway 4 when resting cells grown on lactate-sulfate medium are put in the presence of colloidal sulfur. This shows that the sulfur reductase activity is constitutive and corresponds to the fact that colloidal sulfur grown cells do not contain more cytochrome c3 (or another sulfur reductase) than lactate-sulfate-grown cells. 相似文献
The carotenoids bound to reaction centers of wild, Ga and GlC strains of Rhodopseudomonas spheroides, of Rhodospirillum rubrum, strain S1 and of Rhodopseudomonas viridis, yield very similar, but unusual resonance Raman spectra. Through a comparison with resonance Raman spectra of 15,15′-cis-β-carotene, these carotenoids are shown to assume cis conformations, while the corresponding chromatophores contain all-trans forms only. These cis conformations likely are identical for all the carotenoids studied. They remain unaffected by variations of temperature from 20 to 300 K as well as by the redox state of . They are unstable, being rapidly isomerised towards the all-trans forms when extracted from the reaction centers. The possible nature of these conformers is discussed on the basis of their electronic and vibrational spectra. 相似文献
Klebsiella K23 capsular polysaccharide has been investigated by the techniques of hydrolysis, methylation, Smith degradation-periodate oxidation, and base-catalysed degradation, either on the original or the carboxyl-reduced polysaccharide. The structure was found to consist of a tetrasaccharide repeating-unit, as shown below. The anomeric configurations of the sugar residues were determined by 1H-and 13C-n.m.r. spectroscopy on the original and degraded polysaccharides.相似文献
When single mast cells were isolated by micromanipulation, specific H-2 antigen-bearing mast cells were degranulated upon incubation with alloimmune sera (DAAD). When specific alloantigens were presented by lymphoid cells only, no degranulation occurred. Only antigen-bearing mast cells were degranulated, irrespectively of the presence of antigen-bearing lymphoid cells. Therefore, in DAAD, anaphylactic alloantibodies can and must recognize specific H-2 antigens on the mast cell membrane and simultaneously deliver the degranulation signal, through an Fc-Fc receptor interaction on the surface of the same mast cell. 相似文献