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991.
As a step toward understanding of the tissue specificity of cellular transformation by RNA tumor viruses were looked for the presence of a putative brain specific regulatory (identifier) sequence (C82B) in the genome of various oncornaviruses. The genomes of Harvey murine sarcoma virus and Rous sarcoma virus contain sequences flanking the viral oncogenes with greater than 80% and greater than 60% homology to C82B, respectively. We suggest that identifier sequences acquired by oncoviruses may determine the potential target cells of malignant transformation after virus penetration. 相似文献
992.
Gábor Szöcs Miklós Tóth Hans Jürgen Bestmann Otto Vostrowsky 《Entomologia Experimentalis et Applicata》1984,36(3):287-291
The binary mixture of the hydrocarbons (3Z,6Z,9Z)-3,6,9-nonadecatriene and (6Z,9Z)-6,9-nonadecadiene is a sex attractant for males of Alsophila quadripunctata Esp. (Lepidoptera, Geometridae). Triene/diene ratios from 1:1 to 1:0.01 attracted males in the field, the ratios 1:1 and 1:0.7 were most effective. The triene on its own also attracted males, but in significantly lower numbers than the 1:1 mixture. In a dosage test the highest dose, 1800 g of 1:0.8 [triene:diene] mixture applied to rubber caps was most effective. This is the first report of a geometrid sex attractant with field activity containing more than one component.
Zusammenfassung Die binäre Mischung der Kohlenwasserstoffe (3Z,6Z,9Z)-3,6,9-Nonadecatrien [ZZZ3,6,9-19:H] und (6Z,9Z)-6,9-Nonadecadien [ZZ6,9-19:H] in den Verhältnissen 1:1 bis 1:0.01 erwies sich im Freiland als Sexuallockstoff für Männchen von Alsophila quadripunctata (Geometridae, Lepidoptera). Dabei besaß die 1:1-Mischung die beste Fängigkeit, das Nonadecatrien allein lockte schlechter, während das C19-Alkadien unwirksam war. Ein Dosiswirksamkeitstest ergab bei Köderbeladungen von 1.8 mg (Trien:Dien + 1:0.8) die besten Fangergebnisse. Im Verlauf der Untersuchungen wurden weitere zwölf geometrische-oder positionsisomere C19-Polyenkohlenwasserstoffe getestet, wobei keine der geprüften Verbindungen Attraktant-oder Inhibitorwirkung zeigte.相似文献
993.
A comparison of the conformations adopted by some 5-bromovinyl-2''-deoxyuridines and a correlation with their antiviral properties: an X-ray study. 下载免费PDF全文
Crystal structures of (Z)-5-(2-bromovinyl)-2'-deoxyuridine, 3',5'-di-O-acetyl-(E)-5-(2-bromovinyl)-2'-deoxyuridine and 3',5'-di-O-p-chlorobenzoyl-5-(2-dibromovinyl)-2'-deoxyuridine are compared with each other and with that of the most potent antiviral agent (E)-5-(2-bromovinyl)-2'-deoxyuridine (E-BVDU) reported earlier. A comparison of the conformation of 3',5'-di-O-acetyl-pyrimidine nucleoside structures in which intermolecular hydrogen bond network formation is minimized, with those of their parent compounds has shown that the greatest change in rotation about the glycosyl bond and in the sugar ring pucker is exhibited by E-BVDU. Upon acylation this molecule changes from C2'-endo/C3'-exo conformation to C3'-endo/C4'-exo conformation. The relevance of these structures upon the biological activity of the nucleosides and in particular to their ability to be a substrate for thymidine kinase is discussed. 相似文献
994.
The genetic determination of callus induction, total plant regeneration and green plant regeneration from anther culture were studied using a Chinese Spring/Cheyenne substitution series. All the three characteristics were found to be polygenically determined, but their inheritance was independent from one another. The 7A and 18 chromosomes had a considerable effect on callus induction. In the case of total plant regeneration the most influential chromosome as the 3A while the 2D chromosome showed a definite influence on green plant regeneration. The interaction between the genetic background of the recipient plant and the substituted chromosome plays an important role in the manifestation of the studied features. 相似文献
995.
G G Gasanov R Sh Ibragimov G L Kovács G Szabó G Telegdy 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1988,38(1):129-134
The paper deals with the effect of oxytocin (OXT) and its antagonist--oxytocin antiserum (ANT) microinjected in the ventral hippocampus--on learning of heroin intravenous self-administration in rats. OXT weakened the processes of heroin self-administration, while ANT in contrast improved the learning. The results of the study and data analysis suggest that endogenous OXT in the ventral hippocampus is involved in the mechanisms of behavioural reactions. 相似文献
996.
J Sepr?di J Erchegyi Z Vadász I Teplán I Mez? B Kanyicska M Kovács S Vigh 《Biochemical and biophysical research communications》1987,144(3):1214-1221
New agonists related to gonadotropin-releasing hormone (GnRH) have been synthesized that are comparable in potency to the GnRH and its superagonists for release of LH and estrus suppression without substitutions with D- or unnatural amino acids in position 6. We now report a series of L-beta-aspartyl-6 GnRH analogs containing only naturally occurring L-amino acids in the whole sequence, exhibiting considerable in vivo biological activity. Dose and time dependent LH release capability of the different analogs in adult male mice, estrus suppression comparisons and blockade of ovulation in female rats are given. The incorporation of L-Asp-OMe and L-Asp-OBzl in position 6 of GnRH resulted in the most potent GnRH agonists (to 12-20xGnRH potency) in this series inducing a biphasic biological response similar to the D-amino acid-6 substituted superactive GnRH analogs. A correlation between the LH releasing potencies of the analogs and their HPLC retention times was also investigated. Peptide synthesis were achieved using either solid phase or solution phase methodology. 相似文献
997.
Eva ZelenÁ 《Biologia Plantarum》1987,29(2):123-128
D,L-indol-3-yllactie acid was applied at concentrations 0.2 – 20 mg 1-1 (10-6–10-4M) to the roots of 3-d-old intact maize seedlings grown in the dark and in the light. By day 3 after application, ILA at lower
concentrations (0.2–1 mg l-1) caused slight increase in the mass of etiolated plants, mainly roots. Shoot and root length was not increased. ILA at concentrations
equal to, or greater than, 2 mg 1-1 reduced the length of the main roots and from 10 mg 1-1 on also the length of the shoots. In contrast, root mass was decreased by higher ILA concentrations to a lesser extent than
shoot mass. The response to ILA application of etiolated seedlings differed from that of the seedlings grown in the light
only at 20 mg 1-1. The inhibitory effect was more pronounced in the case of quickly growing etiolated plants. 相似文献
998.
Elena MasarovičovÁ 《Biologia Plantarum》1988,30(4):285-293
Growth, carbon uptake and carbon utilization in leaves of various growing phase shoots (GPS) on beech trees(Fagus sylvatica L.) growing under different light conditions were compared. The values of photosynthetic capacity (maximum daily net photosynthetic
rate, Pn max) were used as comparable parameters.
Daily time and irradiance (I, PhAR), when PN max was attained, were investigated similarly. Statistically significant differences
were found in growth, Pn max and SLM (specific leaf mass) between different GPS and within the same stand, as well as within
the same GPS and different stands. Pn max and SLM increased in the leaves of GPS I (spring - plagiotropic shoots) on trees
from a sun stand from May till September. At the end of the growing season, the spring leaves exhibited, in comparison with
the summer ones, intensive senescence, but leaves of the GPS II and III (summer -orthotropic shoots) evidently attained higher
values of Px max and SLM at higher I (PhAR).
The correlation of growth, PN max and SLM in relation to environmental conditions, as well as the importance of transport,
distribution and utilization of assimilates for annual carbon gain and biomass production are discussed in detail. 相似文献
999.
Treatment of mice with both leupeptin (0.06 mg/g body wt) and vinblastine (0.05 mg/g body wt) for 2 h caused a many-fold enlargement of the autophagic-lysosomal compartment of pancreatic acinar, seminal vesicle epithelial, and liver parenchymal cells. In all three types of cells a predominance of large, dense bodies was seen after leupeptin treatment and that of typical autophagic vacuoles were seen after vinblastine treatment. An exponential decrease of the volume fraction of autophagic vacuoles was observed in leupeptin-treated cells after the administration of cycloheximide (0.2 mg/g body wt). The half-life of autophagic vacuoles estimated from the decay curve was 5.3, 5.7, and 6.6 min for pancreatic, seminal vesicle, and liver cells, respectively. Our data suggest that sequestered cytoplasmic material rapidly enters the lysosomes in leupeptin-treated cells and accumulates in this compartment. In contrast, no regression of the autophagic vacuole compartment of pancreatic and seminal vesicle cells was observed after the administration of cycloheximide to animals pretreated with vinblastine, and only a slight decrease was seen in liver cells. These observations show that the lifetime of autophagic vacuoles is prolonged by vinblastine resulting in their accumulation in the cells. However, our measurements also lend support to the view that in addition to the accumulatory effect on undegraded cytoplasmic material, stimulation of sequestration may play a role in the enlargement of the autophagic lysosomal compartment after treatment with leupeptin as well as with vinblastine in all three types of cells investigated. 相似文献
1000.
X Yang L Zhang A Kovács C Tobback R H Foote 《Molecular reproduction and development》1990,27(2):118-129
The objective of this research was to study efficiency of embryo development following transfer of blastomeres into the perivitelline space of oocytes. Single blastomeres from 8-, 16-, and 32-cell embryos were obtained following mucin coat and zona pellucida removal by combined treatments with pronase and acidic phosphate-buffered saline (PBS, pH = 2.5). Blastomeres were separated by pipetting with a fire-polished micropipette following incubation in Ca+(+)-free PBS for 15 min at 39 degrees C. This procedure resulted in over 97% blastomere separation. For ease of blastomere insertion, oocytes were placed in droplets of 0.5 M sucrose in PBS (SPBS) during micromanipulation. To functionally enucleate oocytes some were stained with Hoechst 33342 DNA stain and irradiated. A single 8- or 16-cell blastomere was aspirated into an injection pipette (35 microns or 25 microns at the tip, respectively) and inserted into the perivitelline space of an irradiated or non-irradiated oocyte, but not fused with the oocyte. This micromanipulation procedure did not affect development of individual blastomeres into blastocysts or trophectoderm vesicles when compared with cultured control single blastomeres (P greater than .05). When the inserted blastomere was induced to fuse with an intact non-irradiated oocyte under an electric field, 56-57% were fused and 39-45% of the fused and activated oocytes developed to morulae or blastocysts. When an inserted blastomere (from 8-32-cell embryos) was induced to fuse with a functionally enucleated oocyte treated by Hoechst 33342 staining, followed by washing and UV-light irradiation, 63-66% of them were fused, but only 15-22% developed to the morula or blastocyst stage. This research demonstrated that the use of hypertonic medium treated oocytes greatly improved the ease and success rate of blastomere subzona insertion, but the value of functionally enucleated oocytes as recipient cells for nuclear transfer requires further investigation. 相似文献