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1.
Interferon- (IFN-) and tumor growth inhibitory factor (TGIF) were inducedin vitro in the supernatant from mixed culture of human peripheral blood mononuclear cells (PBMC) and OK-432. TGIF activity was determined by growth inhibition of a human gastric adenocarcinoma cell line, MK-1 cells, and IFN- activity was measured by radioimmunoassay. The production of TGIF and IFN- was time-dependent, reaching its maximum around 48 hrs. Although there was no significant correlation between TGIF production and IFN- production, combination of a subthreshold concentration of recombinant IFN- (rIFN-) and TGIF induced significant growth inhibition of MK-1 cells. This fact indicates that the effects of rIFN- and TGIF are synergistic. The antiproliferative effect of these cytokines are highly species-specific, and their synergistic effects were also species-specific. rIFN--sensitive and -resistant clones were successfully established from the original MK-1 cell line; those clones are both sensitive to TGIF. Synergistic antiproliferative effects were found when the rIFN--sensitive clone, but not the resistant clone, was used as a target, suggesting that the synergistic effects require the target cells' sensitivity to IFN-. These results indicate that the synergistic effects of TGIF and IFN- may produce a clinical antitumor action in cancer patients receiving OK-432 administration.  相似文献   

2.
From anoxic sewage sludge a new strictly anaerobic, spore-forming bacterium was isolated with 2-hydroxybutyrate as sole substrate. 2-, 3-, and 4-hydroxybutyrate, 4-chlorobutyrate, crotonate, vinylacetate, and pyruvate were fermented to acetate and butyrate. Fructose was converted to acetate, butyrate, butanol, and H2. Lactate and acrylate were fermented to acetate and propionate. Cells pregrown with lactate fermented 2-hydroxybutyrate to butyrate, propionate and acetate. No inorganic electron acceptors were reduced. The DNA base ratio was 32.0±1.0 mol % and was similar to that of Clostridium propionicum, which was determined to be 35.3±0.5 mol %. Strain LuHBu1 is described as type strain of a new species, Clostridium homopropionicum sp. nov. Another isolate obtained from marine sediment degraded 2-and 3-hydroxybutyrate to acetate and butyrate and was in some respects similar to the known species Ilyobacter polytropus.  相似文献   

3.
Summary We have determined the sequence of a rat A3/A1-crystallin complementary DNA (cDNA) clone and the (partial) sequence of the human B3-crystallin gene. Calculation of the ratio of silent to nonsynonymous substitution between orthologous A3/A1-, B3-, and other - and -crystallin sequences revealed that the region encoding the two globular domains of the A3/A1-crystallin sequence is the best conserved during evolution, much better than the corresponding region of the B1-, B3-, or the -crystallin sequences, and even better (at least in the rodent/frog comparison) that the well-conserved A-crystallin sequence. Remarkably, the rate of change of the A3/A1-crystallin coding sequence does not differ in the rodent and primate lineages, in contrast with previous findings concerning the evolution rates of the A- or -crystallin sequences in these two lineages. Comparison of the regions that encode the four motifs of the -crystallin between orthologous mammalian sequences showed that the extent of nonsynonymous substitution in each of these four homologous motif regions is the same. However, when the orthologous -crystallin genes of more distantly related species (mammals vs chicken or frog) are compared, the extent of nonsynonymous substitution is higher in the regions encoding the external motifs I and III than in the regions encoding the internal motifs II and IV. This phenomenon is also observed when paralogous members of the /-crystallin supergene family are compared.  相似文献   

4.
Clumps of white crystals present in 40-day-old malt agar cultures of Holwaya mucida were isolated as long white needles by crystallization from ethanol following short extraction with chloroform. The levorotary compound ([] 289 21 =-193.8°) was recognized as a -lactone (C17H20O5) by infrared and mass spectrometry. It was identified as 7-methoxy-3a, 10b-dimethyl-1, 2, 3, 3a, 5a, 7, 10b, 10c-octahydro-4H, 9H-furo[2, 3, 4 : 4, 5]naphtho[2, 1-c]pyran-4, 9-dione, a labdane-derived compound known as antibiotic LL-Z1271. Preparative thin-layer chromatography of the mother liquor afforded 2 minor metabolites. One was identified as LL-Z1271, the demethylated analogue of LL-Z1271. The other one named LL-Z1271, was recognized as a compound related to and : its structure could not be fully elucidated. H. mucida (anamorph: Crinula calciiformis) has no taxonomic relationship with two other LL-Z1271 producing species viz. Acrostalagmus sp. (= Acremonium cf. atrogriseum) and Oidiodendron truncatum.  相似文献   

5.
Using an 5-AvaII fragment of the spinach (Spinacia oleracea L.) phosphate translocator cDNA as a probe for a hybridization screening of a pea (Pisum sativum L.) cDNA library we have cloned and sequenced a cDNA clone coding for the phosphate translocator precursor protein from pea chloroplasts. The full-length cDNA clone comprises 42 base pairs (bp) at the 5-non-coding region, a 1206-bp coding region corresponding to a polypeptide of 402 amino-acid residues (relative molecular mass 43 671) and 244 bp at the non-coding 3-region. Determination of the N-terminal sequence of the phosphate translocator from both pea and spinach chloroplasts revealed that the transit peptides consist of 72 and 80 amino-acid residues, respectively. These transit peptides are different from those of other chloroplastic transit peptides in that they both contain an amphiphilic -helix which is located either in close proximity to the processing site in pea or at the N-terminus in spinach. The mature proteins from pea and spinach both contain about 87% identical amino-acid residues and about seven putative membrane-spanning -helices. Some of these -helices have an amphiphilic character and might serve to form a hydrophilic translocation channel through the membrane. The in-vitro synthesized pea precursor protein is directed to the chloroplast and inserted into the chloroplast envelope membrane.Abbreviations bp base pairs - kDa kilodaltons - Mr relative moleculas mass - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis We wish to thank Dr D. Pappin and R. Jakes (AFRC Sequencing Laboratory, Department of Biochemistry, University of Leeds, UK) for performing the N-terminal sequence determinations and are greatful to Dr J. S. Gantt (Botany Department, University of Georgia, Athens, USA) for a pea leaf cDNA library and to Professor J. C. Gray (University of Cambridge, Department of Botany, Cambridge, UK) for helpful discussions. This work was supported by the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, the Science and Engineering Research Council and the Royal Society. D.L.W. was the recipient of the Royal Society Rosenheim research fellowship and K.F. was supported by a fellowship from the Studienstiftung des deutschen Volkes.  相似文献   

6.
Summary A cDNA encoding -ketoacyl-ACP reductase (EC 1.1.1.100), an integral part of the fatty acid synthase type II, was cloned fromCuphea lanceolata. This cDNA of 1276 by codes for a polypeptide of 320 amino acids with 63 N-terminal residues presumably representing a transit peptide and 257 residues corresponding to the mature protein of 27 kDa. The encoded protein shows strong homology with the amino-terminal sequence and two tryptic peptides from avocado mesocarp -ketoacyl-ACP reductase, and its total amino acid composition is highly similar to those of the -ketoacyl-ACP reductases of avocado and spinach. Amino acid sequence homologies to polyketide synthase, -ketoreductases and short-chain alcohol dehydrogenases are discussed. An engineered fusion protein lacking most of the transit peptide, which was produced inEscherichia coli, was isolated and proved to possess -ketoacyl-ACP reductase activity. Hybridization studies revealed that inC. lanceolata -ketoacyl-ACP reductase is encoded by a small family of at least two genes and that members of this family are expressed in roots, leaves, flowers and seeds.  相似文献   

7.
Zoogloea ramigera I-16-M was found to contain two stereospecific acetoacetyl CoA reductases; one was NADP+-linked and d(-)--hydroxybutyryl CoA specific and the other was NAD+-linked and l(+)-isomer specific. The NADP+-linked enzyme, purified approximately 150-fold, had a pH optimum for the reduction of acetoacetyl CoA at 8.1, but no definite pH optimum for the oxidation of -hydroxybutyryl CoA. The apparent Michaelis constants for acetoacetyl CoA and NADPH were 8.3 and 21 M, respectively. The enzyme was markedly inhibited by acetoacetyl CoA at concentrations higher than 10 M.The incorporation of [1-14C]acetyl CoA into poly--hydroxybutyrate (PHB) by bacterial crude extract (containing -ketothiolase, acetoacetyl CoA reductases, enoyl CoA hydratases and PHB synthases) or by a system reconstituted from purified preparations of -ketothiolase, acetoacetyl CoA reductase and PHB synthase, was observed only in the presence of NADPH, but not NADH. Among various enzymes involved in PHB metabolism, only the specific activity of glucose 6-phosphate dehydrogenase was elevated 5-fold within 2 h after the addition of glucose to the cells grown in the basal medium.These findings suggest that, in Z. ramigera I-16-M, acetoacetyl CoA is directly reduced to d(-)--hydroxybutyryl CoA by the NADP+-dependent reductase, and PHB synthesis is at least partially controled by NADPH availability through glucose 6-phosphate dehydrogenase.Non-Standard Abbreviation PHB poly--hydroxybutyrate  相似文献   

8.
Summary Superfusion of synaptosomes prepared from rat olfactory bulb revealed constant basal release of endogenous taurine (Tau), aspartate (Asp), glutamate (Glu) and-aminobutyrate (GABA): their release rates were 110.4 ± 13.0, 30.3 ± 6.7, 93.7 ± 13.1, and 53.3 ± 8.8 pmol/min/mg protein, respectively. The depolarizing-stimulation with 30mM KCl evoked 1.17-, 2.18-, 2.55- and 1.53-fold increases, respectively. Tau release was calcium-independent. However, the perfusion of synaptosomes with Tau (10µM) inhibited the evoked increase in GABA release by 63% without changing basal release, although it did not affect release of Asp and Glu. Phaclofen (10µM, a GABAB receptor antagonist), but not bicuculline (10µM, a GABAA receptor antagonist), counteracted the Tau-induced reduction in GABA release. These data suggest that Tau may be abundantly released from nerve endings of rat olfactory bulb and that it may regulate GABA release through the activation of presynaptic GABAB autoreceptors.  相似文献   

9.
Shih IL  Van YT  Sau YY 《Biotechnology letters》2003,25(20):1709-1712
Various enantiomeric isomers, metals salts and molecular sizes of poly(-glutamic acid), -PGA, produced by Bacillus licheniformis CCRC 12826, were prepared and their antifreeze activities were studied by differential scanning calorimetry. The antifreeze activity of -PGA increased as its molecular weight decreased but was indifferent to its d/l-glutamate composition. The antifreeze activity was cation dependent decreasing in the order Mg2+>>Ca 2+Na +>>K + which follows that of inorganic chlorides in that high ionic charge leads to high antifreeze activity. The mechanism by which the cryoprotective effects of -PGA can be explained is still yet to be determined.  相似文献   

10.
Summary Homogenates and plasma membranes were isolated from the livers of male Fischer 344 rats ranging in age from 19 hr to 92 days postnatal. These plasma membranes exhibited comparable levels of purity: protein yields were 2–2.5%; relative specific activities of 5-nucleotidase and ouabain-sensitive Na+/K+-ATPase were from 8–11 and from 12–19, respectively. 5-nucleotidase and ouabain-sensitive Na+-K+-ATPase displayed distinct and different developmental patterns. The activity of -glutamyltranspeptidase was found to be at exceptionally high levels in isolated plasma membranes immediately after birth and to decline precipitously thereafter achieving and maintaining low levels from days 3–21 postnatal. Liver plasma membrane -glutamyltranspeptidase activity was observed to increase 9.2 fold from this low point, first rising on day 21, peaking on day 40 and returning to low levels by day 56. From day 56 day to 92 postnatal, -glutamyltranspeptidase activity was expressed at a uniformly low level but a level 2 fold higher than that preceeding the rise at day 40. The hormone determinants of these developmental changes in -glutamyltranspeptidase activity are discussed.  相似文献   

11.
Role of Glutathione in the Response of Escherichia coli to Osmotic Stress   总被引:1,自引:0,他引:1  
The growth of Escherichia coli mutants deficient in glutathione synthesis (gshA) and in glutathione reductase (gor) was suppressed in medium of elevated osmolarity. A mutant in -glutamyl transpeptidase (ggt) displayed better ability for osmoadaptation than the parental strain. The unfavorable effect of the gsh mutation on osmoadaptation of growing E. coli cells was more pronounced at low concentrations of K+ in the medium. An increase in osmolarity caused an increase in the intracellular content of glutathione. Changes in the extracellular glutathione level were biphasic: the glutathione level rapidly decreased during the first stage of the response and increased during the second stage. The changes in glutathione levels suggest that under hyperosmotic shock the glutathione transport from the medium into the cell can contribute to the intracellular glutathione accumulation. Changes in the level of intracellular K+ were similarly biphasic: a rapid increase in the K+ level during the first stage of the response to hyperosmotic shock changed to a gradual decrease during the second stage. In mutant gshA cells adapted to osmotic shock, the intracellular K+ level was markedly higher than in the parental strain cells. The possible role of glutathione in the response of E. coli to osmotic shock is discussed.  相似文献   

12.
Bacillus subtilis(natto) Takahashi, used to prepare the fermented soybean product natto, was grown in a basal medium containing 5% (w/w) sucrose and 1.5% (w/w) l-glutamate and produced 58% (w/w) poly(-glutamic acid) and 42% (w/w) levan simultaneously. After 21 h, 40–50 mg levan ml-1had been produced in medium containing 20% (w/w) sucrose but without l-glutamate. In medium containing l-glutamic acid but without sucrose, mainly poly(-glutamic acid) was produced. Revisions requested 28 August 2004/14 October 2004; Revisions received 11 October 2004/22 November 2004  相似文献   

13.
Summary Bladder cancer cells were stimulated with urine obtained from patients with superficial bladder cancer who had received treatment using intravesical bacillus Calmette-Guérin (BCG). The urine from the first 12 h following each of six BCG instillations was collected and examined for its biological effect. We evaluated effects that had previously been attributed to cytokines detected in the urine of such patients. The modulation of MHC class II antigen and intercellular adhesion molecule-1 (ICAM-1) expression were studied. Using neutralizing polyclonal antibodies to interferon and tumour factor the relative contribution of these molecules to the effects investigated were determined. When cells were stimulated for up to 48 h with first-instillation urine, little effect was seen in any of the parameters investigated. Urine from the sixth instillation, however, proved to be a potent immunomodulatory agent, inducing MHC class II molecule and ICAM-1 expression. Urine from instillations two to five mediated increasing immunomodulatory effects. When sixth-instillation urine samples were treated with neutralizing antibodies to interferon prior to their addition to the bladder cancer cells, a marked and significant decrease in their potency was observed. Only in urine from one patient did any immunomodulatory capability remain after antibody treatment. Neutralizing antibodies to tumour necrosis factor , however, failed to reduce the ability of any patient's urine to induce ICAM-1 expression. When both antibodies were used simultaneously no further decrease in potency was observed. These studies demonstrate for the first time the potential immunomodulatory and cytotoxic effects of urine produced by patients receiving intravesical BCG. Furthermore, in all samples tested, the major immunomodulatory component was shown to be interferon . Although tumour necrosis factor is produced as a result of BCG therapy, this cytokine did not appear to contribute to the parameters investigated. namely the induction of HLA class II antigens, and cell-surface ICAM-1.  相似文献   

14.
A cyclic somatic embryogenic system was used to induce mutations in cassava variety PRC 60a in vitro. Globular-stage somatic embryos were selected as suitable experimental materials, and 50 Gy of -rays was determined to be the optimal dose for inducing mutations. During subsequent field trials, more than 50% of the regenerated mutant lines varied morphologically from wild-type plants. Consequently, we used this approach to induce genetic variability for obtaining novel cassava cultivars. Among the different mutant lines obtained, lines S14 and S15 showed large morphological variations. In 10-month-old S14 and S15 mutant lines, storage root yield was reduced 17-fold and 60-fold, respectively, compared to wild-type plants, while the storage roots of S15 mutant plants also exhibited an almost 50% decrease in starch content and a significant reduction (30%) in amylose content. These two features were observed throughout the different developmental stages of the storage roots in S15 plants.Abbreviations BA 6-Benzylaminopurine - 2,4-D 2,4-Dichlorophenoxyacetic acid - EMS Ethylmethanesulfonate - IBA Indole-3-butyric acid  相似文献   

15.
The presence of -butyrolactone autoregulators and their receptor proteins were investigated in five representative strains of non-Streptomyces actinomycetes producing commercially important secondary metabolites. Ethyl acetate extracts of culture were assayed using wild-type S. virginiae for virginiae butanolide, S. lavendulae FRI-5 for IM-2, and S. griseus HH1 for A-factor. Actinoplanes teichomyceticus and Amycolatopsis mediterranei were shown to produce autoregulators. Corresponding autoregulator-binding activities were found in the crude cell-free lysates of these strains, using the binding assay with tritium-labeled autoregulator analogues as ligands, which suggests that non-Streptomyces actinomycetes might have autoregulator-dependent signaling cascades.  相似文献   

16.
The relative potency of interferon (IFN), interferon (IFN), and interferon (IFN) in inducing the expression of HLA class I antigens, as well as their capacity to counteract the inhibition induced by glucocorticoid hormones on HLA class I antigen expression, were analysed in the human melanoma cell line M14, both at membrane and at mRNA level. The data obtained indicate that (a) IFN enhance with different potency (IFN>IFN>IFN) the expression of HLA class I antigens in M14 cells, (b) prednisone inhibits HLA class I antigen expresion, (c) glucocorticoid hormones, when associated with IFN or IFN, inhibit the HLA class I enhancement induced by IFN alone, and ffinally, (c) the association between 1 M prednisone or 1 M deflazacort and IFN seems to potentiate the enhancing capacity of IFN on the expression of HLA class I molecules at the mRNA level. These findings, if confirmed, might indicate that IFN and glucocorticoid hormones are not mutually exclusive in the management of human melanoma.  相似文献   

17.
Summary Evidence is presented for the introduction of functional copies of the GUS-reporter gene with plastid regulatory signals into chloroplasts after treatment of Nicotiana plumbaginifolia leaf protoplasts with PEG. GUS-activity is found in cells derived from protoplasts treated with PEG in the presence of plasmids harbouring the GUS-gene under the control of plastid promoter and terminator signals (plastid-specific reporter gene constructions). The activity is maintained after chloroplast isolation and incubation with the protease thermolysin under conditions sufficient to completely remove the much higher transient nuclear/cytoplasmic expression of a GUS-gene carrying the CaMV 35S-promoter. Likewise, GUS-activity derived from a plasmid coding for the nuclear/cytoplasmic expression of the reporter gene with a plastid transit presequence is also maintained after these procedures. These results indicate that PEG-treatment is a suitable protocol by which to introduce DNA into chloroplasts for the study of transient gene expression.  相似文献   

18.
N(3, 4-dimethoxycinnamoyl) anthranilic acid (Tranilast) inhibits antibody-mediated hypersensitivity reactions, and is an effective drug for patients with bronchial asthma or allergic rhinitis. Interferon- (IFN-) production of ovalbumin (OA)-stimulated peripheral blood mononuclear cells (PBMCs) from hen's egg-sensitive patients with atopic dermatitis (AD) was significantly higher than those of healthy controls. Tranilast inhibited this IFN- production. Moreover, interleukin-2 (IL-2) production of OA-stimulated PBMCs from hen's egg-sensitive patients with AD was also inhibited by Tranilast. Our results suggest that Tranilast can be used to the patients with food sensitive AD.Abbreviations PBMCs peripheral blood mononuclear cells - OA ovalbumin - BSA bovine serum albumin - AD atopic dermatitis - IL-2 interleukin-2 - IFN- interferon- - Tranilast N(3, 4-dimethoxycinnamoyl) anthranilic acid - IL-4 interleukin 4 - IL-5 interleukin 5  相似文献   

19.
Genetic study of -glucan content and -glucanase activity has been facilitated by recent developments in quantitative trait loci (QTL) analysis. QTL for barley and malt -glucan content and for green and finished malt -glucanase activity were mapped using a 123-point molecular marker linkage map from the cross of Steptoe/Morex. Three QTL for barley -glucan, 6 QTL for malt -glucan, 3 QTL for -glucanase in green malt and 5 QTL for -glucanase in finished malt were detected by interval mapping procedures. The QTL with the largest effects on barley -glucan, malt glucan, green malt -glucanase and finished malt glucanase were identified on chromosomes 2,1,4 and 7, respectively. A genome map-based approach allows for dissection of relationships among barley and malt glucan content, green and finished malt -glucanase activity, and other malting quality parameters.  相似文献   

20.
Summary Electrical potential differences across the plasma membrane () of the yeastPichia humboldtii were measured with microelectrodes (filled with 0.1m KCl) inserted into cells immobilized in microfunnels. The registered signals were reproducible and stable for several minutes. On attainment of stable reading for the specific membrane resistanceR sp was determined by applying square-current pulses to the preparation. Both andR sp were pH dependent and displayed equal but opposite deflection, reaching its maximal value of –88±9 mV (n=13) andR sp its minimal value of 10 k·cm2 (maximal conductance) at pH 6.5. Uncouplers and the polyene antibiotic nystatin depolarized the cells, decreasing to –21±15 mV (n=10) with concomitant decrease ofR sp. Comparison of values from microelectrode measurements with those calculated from the steady-state distribution of tetraphenylphosphonium ions agreed within 10 mV under all physiological conditions tested, except at pH values above 7.0. During microelectrode insertion transient voltage signals (a few msec long) were detected by means of an oscilloscope. These voltage signals were superimposed on the stable recordings described above. These short voltage signals disappeared in uncoupled cells. The closely related values obtained by two independent methods (direct measurements with microelectrodes and calculation from steady-state distribution of a lipophilic cation) provide evidence that these values reffect the true membrane potential of intact cells.  相似文献   

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