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11.
Shoshana Morecki Evelyn Karson Kenneth Cornetta Attan Kasid Paul Aebersold R. Michael Blaese W. French Anderson Steven A. Rosenberg 《Cancer immunology, immunotherapy : CII》1991,32(6):342-352
Summary Studies were undertaken to test the susceptibility of individual T cell subpopulations to retroviral-mediated gene transduction. Gene transfer into human tumor-infiltrating lymphocytes (TIL) or peripheral blood mononuclear cells (PBMC) was carried out by transduction with an amphotropic murine retroviral vector (LNL6 or N2) containing the bacterialneo
R gene. The presence of theneo
R gene in the TIL population was demonstrated by Southern blot analysis, detection of the enzymatic activity of the gene product and by the ability of transduced TIL to proliferate in high concentrations of G418, a neomycin analog that is toxic to eukaryotic cells. The presence of theneo
R gene in TIL did not alter their proliferation or interleukin-2 dependence compared to nontransduced TIL. The differential susceptibility of CD4+ and CD8+ lymphoid cells to the retro-virus-mediated gene transfer was then tested. Transduction of heterogeneous TIL cultures containing both CD4+ and CD8+ cells resulted in gene insertion into both T cell subsets with no preferential transduction frequency into either CD4+ or CD8+ cells. In other experiments highly purified CD4+ and CD8+ T cell subpopulations from either TIL or PBMC could be successfully transduced with theneo
R gene as demonstrated by Southern blot analysis and detection of the gene product neophosphotransferase activity. No such activity or vector DNA could be detected in controls of nontransduced cells. In these highly purified cell subsets the distinctive T cell phenotypic markers were continually expressed after transduction, G418 selection and long-term growth. Clinical trials have begun in patients with advanced cancer using heterogeneous populations of CD4+ and CD8+ gene-modified TIL.
Current address: Bone Marrow Transplantation, Hadassah University Hospital, 91120 Jerusalem, Israel 相似文献
12.
Porphyridium cultures grown on either nitrate or ammonium as the nitrogen source showed similar patterns of growth and cell wall polysaccharide production. The effect of nitrogen on growth and cell wall polysaccharide production was studied by applying three regimens of supply: batch mode, in which nitrate was supplied at the beginning of the experiment and became depleted at day 6; continual mode, in which nitrate was added daily; and deficient mode, in which the cells were cultured in a nitrate-free medium. Growth was similar in the batch- and continual-mode cultures, whereas it was totally inhibited in the deficient-mode culture. Polysaccharide content (per volume) was highest in the batch-mode culture and lowest in the deficient-mode culture. However, polysaccharide production per cell was similar in the continual- and deficient-mode cultures, the highest value being found in the batch-mode culture. In addition to its effect on polysaccharide content, nitrogen affected the polysaccharide distribution between soluble and bound polysaccharides. In the deficientmode culture, most of the cell wall polysaccharide was dissolved in the medium. 相似文献
13.
Summary The environmental conditions prevailing in Israel make marine algae an attractive crop for the production of valuable chemicals. A marine species of Porphyridium seems to fit this purpose.The unicellular red alga Porphyridium is encapsulated by a polysaccharide envelope that is present in the gel state. This polysaccharide is an acidic heteropolymer composed of sulfated sugars. It forms ionic bridges through divalent cations, thus reaching a very high molecular weight. The thickness of the polysaccharide capsule varies according to the phase of growth and the growth conditions. Its outer part dissolves in the growth medium, which becomes progressively more viscous. Sulfated polysaccharides form theramlly reversible gels similar to agar and carrageenan, which are usually extracted from marine macroalgae. These gels have been finding increasing use in commercial applications as gelling agents, thickeners, stabilizers, and emulsifiers.We have done experiments on the cultivation of a marine species of Porphyridium for the production of polysaccharides. This unicellular alga has an advantage over the macroalgae due to its relatively faster growth rate and the possibility to regulate its growth. The potential for production of the polysaccharide, both that dissolved in the external medium and that attached to the cell (including an intracellular fraction), and the effects of growth conditions on productivity were suudied in the laboratory. Porphyridium was also cultivated outdoors in seawater in 1-m2 ponds and its growth potential investigated. 相似文献
14.
Developmental history and behavior of Eretmocerus mundus Mercet, a parasitoid of Bemisia tabaci was studied at 25°C. The eggs may be laid under all four nymphal instars but not under the pupa. Yet the second and third instars are preferred. The egg hatches only under the fourth instar or the pupa. Developmental medians at 25°C are: Instar I-2.5, II-4, II-4, prepupa-2 and pupa 8 days. When ovipositing, the female stands at an angle of 90° to the host, with wings raised and inserts the ovipositor under the whitefly nymph. The egg is laid close to the insertion point of the whitefly's proboscis into the leaf. After oviposition, the female apparently marks the host while drumming on it with her hind legs. She distinguishes already parasitized hosts from unparasitized ones and refrains from laying under the former. Discrimination is accomplished after antennal drumming only.
Les parasitoïdes de Bemisia tabaci (aleyrodidae) en Israel: développement, ponte et sélection des hôtes ches Eretmocerus mundus (aphelinidae)
Résumé Le développment et le comportement de E. mundus, parasitoïde de B. tabaci, ont été étudiés à 25°C. Les oeufs sont pondus sous les quatre stades larvaires (les deuxième et troizième sont préférés) mais pas sous les nymphes. Les oeufs n'éclosent que sous les larves du quatrième stade ou les nymphes. Les temps de développement médiaux sont à 25°, les suivants: stade I: 2,5j; stade II: 4j; stade III: 4j et nymphe 8j. Pendant la ponte, la femelle est à 90° sur son hôte, les ailes dressées, et insère sa tarière sous la larve d'aleurode. L'oeuf est déposé près du point d'insertion de la trompe dans la feuille. Après l'émission, la femelle marque apparemment son hôte pendant qu'elle tambourine avec ses pattes postérieures. Elle distingue les hôtes parasités ou non, et limite sa ponte dans les premiers. La sélection est effectuée seulement après tambourinage antennaire.相似文献
15.
Embryos were collected from two-year-old donor mares and transferred surgically during 1983 and 1984. The overall embryo recovery rate from two-year-old donors was 36.3%. Over both years, 71.4% of the donors () provided at least one embryo. There was a trend both years for slightly higher embryo recovery rates prior to August 1 (47.7%), as compared to after August 1 (31.1%). Pregnancy rates in recipient mares after surgical embryo transfer were not affected by month of the breeding season. However, there was a trend for improved pregnancy rates when embryos were transferred after August 1 (87.5%), as compared to before August 1 (70.0%). There was a 8.3% incidence of fetal loss between Days 15 and 35 of gestation in recipients. The incidence of fetal loss between Days 35 and 60 of gestation was 2.7%. Based on these data, the chance of obtaining a pregnancy from a two-year-old mare is 28.2% (36.3% recovery × 77.7% pregnancy rate). Thus embryo transfer may prove to be a beneficial tool for obtaining foals from two-year-old donor mares. 相似文献
16.
17.
Shoshana Klein Drora Zenvirth Vardit Dror Arnold B. Barton David B. Kaback Giora Simchen 《Chromosoma》1996,105(5):276-284
The preferred positions for meiotic double-strand breakage were mapped on Saccharomyces cerevisiae chromosomes I and VI, and on a number of yeast artificial chromosomes carrying human DNA inserts. Each chromosome had strong
and weak double-strand break (DSB) sites. On average one DSB-prone region was detected by pulsed-field gel electrophoresis
per 25 kb of DNA, but each chromosome had a unique distribution of DSB sites. There were no preferred meiotic DSB sites near
the telomeres. DSB-prone regions were associated with all of the known ”hot spots” for meiotic recombination on chromosomes
I, III and VI.
Received: 19 March 1996; in revised form: 26 July 1996 / Accepted: 18 August 1996 相似文献
18.
The properties of acetohydroxy acid synthase (AHAS, EC 4.1.3.18) from wild-type Chlorella emersonii (var. Emersonii, CCAP-211/11n) and two spontaneous sulfometuron methyl (SMM)-resistant mutants were examined. The AHAS from both mutants was resistant to SMM and cross-resistant to imazapyr (IM) and the triazolopyrimidine sulfonanilide herbicide XRD-498 (TP). The more-SMM-resistant mutant had AHAS with altered catalytic parameters (K
m, specificity), but unchanged sensitivity to the feedback inhibitors valine and leucine. The second mutant enzyme was less sensitive to the feedback inhibitors, but had otherwise unchanged kinetic parameters. Inhibition-competition experiments indicated that the three herbicides (SMM, IM, TP) bind in a mutually exclusive manner, but that valine can bind simultaneously with SMM or TP. The three herbicide classes apparently bind to closely overlapping sites. We suggest that the results with C. emersonii and other organisms can all be explained if there are separate binding sites for herbicides, feedback inhibitors and substrates.Abbreviations AHAS
acetohydroxy acid synthase
- AL
acetolactate
- AHB
acetohydroxybutyrate
- IM
imazapyr
- TP
triazolopyrimidine sulfonanilide herbicide XRD-498
- R
enzyme specificity
- SMM
sulfometuron methyl
This research was supported in part by the United States — Israel Binational Science Foundation (BSF), Jerusalem, Israel (Grant 86-00205) and the Fund for Basic Research, Israel Academy of Sciences. 相似文献
19.
Bruce P. Squires 《CMAJ》1993,149(2):127-130
20.
Motion characteristics of cooled stallion spermatozoa in 2 freezing extenders were studied. Ejaculates from 8 stallions were split into treatments and cooled in thermoelectric cooling units at each of 2 rates. Cooling started at 37 degrees C for Experiments 1 and 3 and at 23 degrees C for Experiments 2 and 4, at a rate of -0.7 degrees C/min to 20 degrees C and from 20 to 5 degrees C, at either -0.05 degrees C/min (Rate I) or -0.5 degrees C/min (Rate II). Percentages of motile (MOT) and progressively motile spermatozoa (PMOT) were determined at 6, 24 and 48 h. Treatments in Experiment 1 were modified skim milk extender (SM); SM + 4% egg yolk (EY); SM + 4% glycerol (GL); and SM + 4% egg yolk + 4% glycerol (EY + GL). At 24 and 48 h, MOT and PMOT were lowest (P < 0.05) for spermatozoa extended in SM + EY; spermatozoa in SM + GL had the highest MOT and PMOT. Thus, glycerol partially protected spermatozoa against the effects of cooling after long-term storage. Treatments in Experiment 2 were SM, semen centrifuged and pellet resuspended in SM (SMc), SM + EY, and semen centrifuged and pellet resuspended in SM + EY (EYc). Spermatozoa in SM + EYc had the highest (P < 0.05) PMOT at 24 h and MOT and PMOT at 48 hours. Spermatozoa in SM + EY (not centrifuged) had the lowest MOT and PMOT at 24 and 48 h, respectively. There was a detrimental interaction between egg yolk and seminal plasma. Extenders in Experiment 3 were Colorado extender (CO3), CO3 + 4% egg yolk (EY), CO3 + 4% glycerol (GL), and CO3 + 4% egg yolk + 4% glycerol (EY + GL). Spermatozoa in CO3 + EY had the lowest (P < 0.05) PMOT at 24 and 48 h. CO3 did not protect spermatozoa cooled in the presence of seminal plasma. Therefore, in Experiment 4 we tested CO3 with seminal plasma present (control) and semen centrifuged and pellet resuspended in CO3 (CO3c), CO3 + EY (EYc), CO3 + GL (GLc) and CO3 + EY + GL (EY + GLc). Spermatozoa in CO3 had the lowest (P < 0.05) MOT and PMOT at all time periods, which suggested a detrimental interaction of this extender with seminal plasma. 相似文献