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21.
Genetic determinants of glutamine synthetase inDrosophila melanogaster: A gene for glutamine synthetase I resides in the 21B3-6 region 总被引:1,自引:0,他引:1
Corrado Caggese Ruggiero Caizzi Maria Pia Bozzetti Paolo Barsanti Ferruccio Ritossa 《Biochemical genetics》1988,26(9-10):571-584
Recombinational and deletion mapping of electrophoretic variants of the glutamine synthetase I isozyme (GSI) in Drosophila melanogaster locates the gene in the 21B region on the second chromosome. We have conducted a genetic analysis of the region extending cytologically from 21A to 21B4-6. Recessive lethal mutations were generated by ethyl methanesulfonate (EMS) and ethyl nitrosourea (ENU) mutagenesis and by hybrid dysgenesis (HD). These lethals fall into seven functional groups, which were partially ordered by complementation with cytologically defined deficiencies of this region generated by hybrid dysgenesis. Two of the EMS- and two of the ENU-induced lethals fulfill biochemical criteria expected for null alleles of the GSI gene. 相似文献
22.
Estimation of the size of freshwater ciliate populations by a sub-sampling technique 总被引:4,自引:4,他引:0
Paolo Madoni 《Hydrobiologia》1984,111(3):201-206
A technique is described for the estimation of the size of ciliate populations based on replicated counts. Sample drops were
taken by automatic pipettes of different volume from activated sludge and from a small oligotrophic stream. Specific aims
were: 1) the estimation of the number of species; 2) the estimation of the number of individual in each species; 3) the selection
of a suitable sub-sample size and number of replicates. For each volume the cumulative increase in species taken in successive
sub-samples was determined. For each species the minimum permissible sub-sample volume and the number of replicates required
for an allowable error of 10% and 25% were determined. Lastly, the relationship between the mean number of individuals counted
for each species and the relative coefficient of variation was visualized. 相似文献
23.
Structure determination of the major asparagine-linked sugar chain of human factor VIII--von Willebrand factor 总被引:4,自引:0,他引:4
P Debeire J Montreuil B Samor C Mazurier M Goudemand H van Halbeek J F Vliegenthart 《FEBS letters》1983,151(1):22-26
N-glycosidically-linked glycans released by hydrazinolysis of human factor VIII/von Willebrand factor (FVIII/vWf) were separated by high-voltage electrophoresis. Five fractions were obtained, one of them representing 60% of the total amount of the N-glycosidically-linked glycans of FVIII/vWf. On the basis of the carbohydrate composition, methylation analysis and 500 MHz 1H-NMR spectroscopy, we describe the primary structure of this major glycan which is of the monosialylated and monofucosylated biantennary N-acetyllactosaminic type. 相似文献
24.
The isomerization of poly-L -proline in different solvents has been studied by NMR spectroscopy. Different resonance signals for the CHα protons have been obtained for the two different helical conformations of thus compound, namely form I and form II. 相似文献
25.
26.
The effect of tryptophan on the biosynthesis of proline has been investigated. Cells of Daucus carota grown in B5 medium supplemented with 5×10–4M tryptophan acquired the ability to grow in the presence of inhibitory concentrations of azetidine-2-carboxylic acid, an analog of proline. When trp was added to carrot cell cultures at sub-growth inhibiting concentrations, overproduction of intracellular free proline was observed. An increase was also observed for lys, his, ala, leu and phe. Likewise, the addition of asparagine, glutamic acid and phenylalanine to the medium stimulated the intracellular increase of free proline and other amino acids.Abbreviations A2CA
azetidine-2-carboxylic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- 5MT
5-methyltryptophan
- P5C
pyrroline-5-carboxylic acid
- f.wt.
fresh weight
- d.wt.
dry weight 相似文献
27.
V Mazzarello A L Dessì 《Bollettino della Società italiana di biologia sperimentale》1990,66(5):441-448
The development of the nail apparatus of the human foetuses from 6th to 18th weeks of pregnancy, was studied by Scanning Electron Microscopy. The main results can be summarized as follows: 1) first structure to appear is nail field defined by continuous shallow grooves; 2) the shape of the nail field is firstly ovoidal and it extends beyond the tip of the finger; later it becomes flat as in the adult nail plate; 3) the globular blebs of periderm cells accumulate mostly in the tip of the finger; 4) the surface of the nail field is first uniform, then it becomes irregular for the increasing of the process of keratinization. 相似文献
28.
Analyses of wheat/rye addition lines by Southern blotting confirmed the presence of sequences related to theSec 1, Sec 2, andSec 3 loci on chromosomes 1R and 2R. Comparison of the 1R and 2R addition lines allowed the identification of -secalin genes atSec 1 andSec 2, respectively, while -secalin and -secalin genes atSec 1 were discriminated by comparative hybridization with three probes: -secalin, total -secalin, and 3 -secalin. The high molecular weight (HMW) secalin genes atSec 3 were identified using a homologous HMW subunit probe from wheat. Gene copy numbers were estimated as about 40–60 for -secalins, 5–10 for -secalins, and 2 for HMW secalins. Comparison of individual plants of cv. Gazelle showed a high degree of polymorphism, particularly for sequences related to -secalins and HMW secalins. 相似文献
29.
Alessandro Stefani Antonio Pisani Nicola B. Mercuri Paolo Calabresi 《Molecular neurobiology》1996,13(1):81-95
Glutamatergic transmission in the central nervous system (CNS) is mediated by ionotropic, ligand-gated receptors (iGluRs), and metabotropic receptors (mGluRs). mGluRs are coupled to GTP-binding regulatory proteins (G-proteins) and modulate different second messenger pathways. Multiple effects have been described following their activation; among others, regulation of fast synaptic transmission, changes in synaptic plasticity, and modification of the threshold for seizure generation. Some of the major roles played by the activation of mGluRs might depend on the modulation of high-voltage-activated (HVA) calcium (Ca2+) currents. Some HVA Ca2+ channels (N-, P-, and Q-type channels) are signaling components at most presynaptic active zones. Their mGluR-mediated inhibition reduces synaptic transmission. The interference, by agonists at mGluRs, on L-type channels might affect the repetitive neuronal firing behavior and the integration of complex events at the somatic level. In addition, the mGluR-mediated effects on voltagegated Ca2+ signals have been suggested to strongly influence neurotoxicity. Rather different coupling mechanisms underlie the relation between mGluRs and Ca2+ currents: Together with a fast, membrane-delimited mechanism of action, much slower responses, involving intracellular second messengers, have also been postulated. In the recent past, the relative paucity of selective agonists and antagonists for the different subclasses of mGluRs had hampered the clear definition of the roles of mGluRs in brain function. However, the recent availability of new pharmacological tools is promising to provide a better understanding of the neuronal functions related to different mGluR subtypes. The analysis of the mGluR-mediated modulation of Ca2+ conductances will probably offer new insights into the characterization of synaptic transmission and the development of neuroprotective agents. 相似文献
30.
A preliminary report on the use of transfer factor for treating stage D3 hormone-unresponsive metastatic prostate cancer 总被引:4,自引:0,他引:4
Dr. Giancarlo Pizza Caterina De Vinci Diego Cuzzocrea Domenico Menniti Ernesto Aiello Paolo Maver Giuseppe Corrado Piero Romagnoli Ennio Dragoni Giuseppe LoConte Umberto Riolo Aldopaolo Palareti Paolo Zucchelli Vittorio Fornarola Dimitri Viza 《Biotherapy》1996,9(1-3):123-132
As conventional treatments are unsuccessful, the survival rate of stage D3 prostate cancer patients is poor. Reports have
suggested the existence of humoral and cell-mediated immunity (CMI) against prostate cancer tumour-associated antigens (TAA).
These observations prompted us to treat stage D3 prostate cancer patients with an in vitro produced transfer factor (TF) able
to transfer, in vitro and in vivo, CMI against bladder and prostate TAA. Fifty patients entered this study and received one
intramuscular injection of 2–5 units of specific TF monthly. Follow-up, ranging from 1 to 9 years, showed that complete remission
was achieved in 2 patients, partial remission in 6, and no progression of metastatic disease in 14. The median survival was
126 weeks, higher than the survival rates reported in the literature for patients of the same stage. 相似文献