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1.
Leaf and shoot explants of Sempervivum tectorum L., taken from 14- and 30-day-old plants germinated in vitro, have been studied by using Murashige-Skoog and White basal media with cytokinins (benzyladenine, kinetin) and auxins (indoleacetic acid, naphthaleneacetic acid, indolebutyric acid) in various concentrations. Explants taken from 14-day-old plants died but 30-day-old leaves and shoots produced yellow and soft, as well as green and hard calluses on Murashige-Skoog medium with 4.4–8.8 M benzyladenine and 0.57 M indoleacetic acid. Shoot organogenesis was induced from green, hard callus in a medium with 2.2 M benzyladenine plus either 1.1 M indoleacetic acid or 2.5 M indolebutyric acid. Whole plants were grown on Murashige-Skoog medium without plant growth regulators. On the other hand, White medium was not suitable for raising Sempervivum tectorum in vitro.Abbreviations BA
benzyladenine
- IAA
indoleacetic acid
- IBA
indolebutyric acid
- MS
Murashige-Skoog
- NAA
napthaleneacetic acid
- W
White 相似文献
2.
Jrn Elsner Johannes Norgauer Gustav J. Dobos Andreas Emmendrffer Erwin Schpf Alexander Kapp Joachim Roesler 《Journal of cellular physiology》1993,157(3):637-643
Flow cytometric analyses were performed to study intracellular single-cell calcium transients ([Ca2+]i) in suspended human neutrophils during the initial phase of N-formyl peptide stimulation. Thereby, two neutrophil populations became apparent. Early maximally Ca2+-responding (high fluorescence) neutrophils and not-yet Ca2+-responding (low fluorescence) neutrophils, but no neutrophils with intermediate levels of [Ca2+]i, were detected. Within 7 s the number of low fluorescence neutrophils decreased and the number of high fluorescence neutrophils increased maximally. This suggests that [Ca2+]i transients occurred abruptly in individual neutrophils within a time interval below 1 s. At lower N-formyl peptide concentrations the lag times of individual neutrophils and the interval time of maximal activation of the [Ca2+]i-responding neutrophil population increased, however the percentage of [Ca2+]i-responding cells decreased. Surprisingly, no influence of the N-formyl peptide concentration on the [Ca2+]i-induced fluorescence signal of the individual cell was observed: it was always in an almost maximal range or not responding. In parallel, binding studies performed with fluorescein-labeled N-formyl peptide revealed that the heterogeneity of [Ca2+]i-responding cells cannot be explained by different receptor occupancy. In summary, this study demonstrates that [Ca2+]i transients induced by N-formyl peptides in suspended individual human neutrophils occur very rapidly in an almost “all-or-none manner” and that the mean increasing fluorescence signal of a calcium indicator within a whole neutrophil population results from varying lag times of the individual cells, rather than from the mean simultaneous progress of many cells. © 1993 Wiley-Liss, Inc. 相似文献
3.
The molecular weight of infectious pancreatic necrosis virus (IPNV) has been determined by analytical ultracentrifugation and dynamic light scattering. The sedimentation coefficient of the virus was found to be 435S. The average value for molecular weight is (55 +/- 7) x 106. The virus genome consists of two segments of double-stranded RNA (molecular weights, 2.5 x 106 and 2.3 x 106), which represents 8.7% of the virion mass. The capsid protein moiety of IPNV consists of four species of polypeptides, as determined by polyacrylamide gel electrophoresis. The number of molecules of each polypeptide in the virion has been determined. There are 22 molecules of the internal polypeptide alpha (molecular weight, 90,000), 544 molecules of the outer capsid polypeptide beta (molecular weight, 57,000), and 550 and 122 molecules, respectively, of the internal polypeptides gamma1 (molecular weight, 29,000) and gamma2 (molecular weight, 27,000). IPNV top component contains only the beta polypeptide species, and its molecular weight is estimated to be 31 x 106. The hydrodynamic diameter and electron microscopic diameter (calculated by catalase crystal-calibrated electron microscopy) of IPNV was compared with those of reovirus and encephalomyocarditis virus. Due to the swelling of the outer capsid, reovirus particles were found to be much larger when hydrated (96-nm diameter) than when dehydrated (76-nm diameter), having a large water content content and low average density. In contrast, IPNV particles are more rigid, having nearly the same average diameter under hydrous (64 nm) as under anhydrous conditions (59.3 nm). Encephalomyocarditis virus has a very low water content and does not shrink at all when prepared for electron microscopy. 相似文献
4.
5.
Dobos Z Lóránd T Hollósy F Hallgas B Eros D Mészáros G Kéri G Idei M 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,799(1):179-183
Capillary electrophoretic (CE) method to characterise Mannich ketones (MKs) containing morpholine moiety was developed. Basicity (pKa,exp) of the MKs was characterised by measured data derived from the electrophoretic mobility values obtained in the CE separation. The MKs were found to be weaker bases than the parent morpholine molecule itself and the experimentally determined basicity values proved to be dependent on the chemical structure of the MKs. Since the basicity of the MKs has an influence on their reactivity and biological activity it seems to be useful to determine experimentally the pKa,exp values of the newly synthesised compounds to support rational drug design or screening of the molecule libraries. 相似文献
6.
Marques MA Espinosa BJ Xavier da Silveira EK Pessolani MC Chapeaurouge A Perales J Dobos KM Belisle JT Spencer JS Brennan PJ 《Proteomics》2004,4(10):2942-2953
Recently the sequence of the Mycobacterium leprae chromosome, the only known obligate intracellular mycobacterium, was completed. It has a dramatic reduction in functional genes, with a coding capacity of only 49.5%, the lowest one so far observed among bacterial genomes. The leprosy bacillus seems to preserve a minimal set of genes that allows its survival in the host. The identification of genes that are actually expressed by the bacterium is of high significance in the context of mycobacterial pathogenesis. In this current study, a proteomic approach was undertaken to identify the proteins present in the soluble/cytosol and membrane subcellular fractions obtained from armadillo derived M. leprae. Proteins from each fraction were separated by two-dimensional gel electrophoresis (2-DE) and identified by mass spectrometry. A total of 147 protein spots were identified from 2-DE patterns and shown to comprise products of 44 different genes, twenty eight of them corresponding to new proteins. Additionally, two highly basic proteins (with pI >10.0) were isolated by heparin affinity chromatography and identified by N-terminal sequencing. This study constitutes the first application of proteomics to a host-derived Mycobacterium. 相似文献
7.
Cho YS Dobos KM Prenni J Yang H Hess A Rosenkrands I Andersen P Ryoo SW Bai GH Brennan MJ Izzo A Bielefeldt-Ohmann H Belisle JT 《Proteomics》2012,12(7):979-991
Purified protein derivative (PPD) has served as a safe and effective diagnostic reagent for 60 years and is the only broadly available material to diagnose latent tuberculosis infections. This reagent is also used as a standard control for a number of in vitro immunological assays. Nevertheless, the molecular composition and specific products that contribute to the extraordinary immunological reactivity of PPD are poorly defined. Here, a proteomic approach was applied to elucidate the gene products in the U.S. Food and Drug Administration (FDA) standard PPD-S2. Many known Mycobacterium tuberculosis T-cell antigens were detected. Of significance, four heat shock proteins (HSPs) (GroES, GroEL2, HspX, and DnaK) dominated the composition of PPD. The chaperone activities and capacity of these proteins to influence immunological responses may explain the exquisite solubility and immunological potency of PPD. Spectral counting analysis of three separate PPD reagents revealed significant quantitative variances. Gross delayed-type hypersensitivity (DTH) responses in M. tuberculosis infected guinea pigs were comparable among these PPD preparations; however, detailed histopathology of the DTH lesions exposed unique differences, which may be explained by the variability observed in the presence and abundance of early secretory system (Esx) proteins. Variability in PPD reagents may explain differences in DTH responses reported among populations. 相似文献
8.
Zusammenfassung Die Zahl der mit einem alkylierenden Agens (Zitostop) in vitro induzierten Mutationen zeigt individuelle Schwankungen.Beim Down-Syndrom, dessen häufige Kombination mit malignen Erkrakungen bekannt ist, und bei 2 Mitgliedern einer Krebsfamilie wird eine statistisch signifikant erhöhte Zahl von induzierten Mutationen gegenüber Gesunden festgestellt.Bei der Ataxia teleangiektasia und bei akuter lymphoblastischer Leukämie im Remissionsstadium sind nur in einigen Fällen Chromosomenaberrationen in vitro gegenüber Normalen induzierbar. Nach unseren Beobachtungen stellt sich die Frage, ob die mit alkylierenden Agentien in vitro durchgeführten Untersuchungen zum Nachweis gesteigerten Mutationsneigung geeignet sind.
Mutations induced in vitro by an alkylating agent (Zitostop) in malignant diseases and syndromes predisposing to malignancy
Summary According to our observations the number of chromosome mutations induced in vitro by an alkylating agent (Zitostop) shows individual variations. In Down's syndrome, which is accompanied by a higher incidence of malignancy, and in two members of a cancer family the number of mutations induced was significantly higher than in controls. In ataxia telangiectasia and in the complete remission phase of acute lymphoid leukaemia the number of mutations induced was higher only in some cases. The question of whether recording the number of chromosome mutations induced by an alkylating agent is a suitable procedure for the detection of an increased mutability or not is left open.相似文献
9.
Prithwiraj De Anita G. Amin Danara Flores Anne Simpson Karen Dobos Delphi Chatterjee 《The Journal of biological chemistry》2021,297(5)
In Mycobacterium tuberculosis (Mtb), surface-exposed Lipoarabinomannan (LAM) is a key determinant of immunogenicity, yet its intrinsic heterogeneity confounds typical structure–function analysis. Recently, LAM gained a strong foothold as a validated marker for active tuberculosis (TB) infection and has shown great potential in new diagnostic efforts. However, no efforts have yet been made to model or evaluate the impact of mixed polyclonal Mtb infections (infection with multiple strains) on TB diagnostic procedures other than antibiotic susceptibility testing. Here, we selected three TB clinical isolates (HN878, EAI, and IO) and purified LAM from these strains to present an integrated analytical approach of one-dimensional and two-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy, as well as enzymatic digestion and site-specific mass spectrometry (MS) to probe LAM structure and behavior at multiple levels. Overall, we found that the glycan was similar in all LAM preparations, albeit with subtle variations. Succinates, lactates, hydroxybutyrate, acetate, and the hallmark of Mtb LAM-methylthioxylose (MTX), adorned the nonreducing terminal arabinan of these LAM species. Newly identified acetoxy/hydroxybutyrate was present only in LAM from EAI and IO Mtb strains. Notably, detailed LC/MS-MS unambiguously showed that all acyl modifications and the lactyl ether in LAM are at the 3-OH position of the 2-linked arabinofuranose adjacent to the terminal β-arabinofuranose. Finally, after sequential enzymatic deglycosylation of LAM, the residual glycan that has ∼50% of α−arabinofuranose -(1→5) linked did not bind to monoclonal antibody CS35. These data clearly indicate the importance of the arabinan termini arrangements for the antigenicity of LAM. 相似文献
10.
Helena del Corral Sara C. París Nancy D. Marín Diana M. Marín Lucelly López Hanna M. Henao Teresita Martínez Liliana Villa Luis F. Barrera Blanca L. Ortiz María E. Ramírez Carlos J. Montes María C. Oquendo Lisandra M. Arango Felipe Ria?o Carlos Aguirre Alberto Bustamante John T. Belisle Karen Dobos Gloria I. Mejía Margarita R. Giraldo Patrick J. Brennan Jaime Robledo María P. Arbeláez Carlos A. Rojas Luis F. García 《PloS one》2009,4(12)