Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “quantitative complementation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMed2026

Proteomic characterization of acidic aqueous extracts from Vicia faba L. pod valves identifies chitinase as a major co-extracted protein macromolecule.

Naturally acidic aqueous extracts from Vicia faba L. pod valves are being explored as sustainable, L-DOPA-oriented plant preparations. Pod valves represent an underutilized processing by-product reported to contain L-DOPA, a compound widely used in Parkinson's disease therapy, while acidic aqueous media may help preserve its physicochemical stability. However, the protein macromolecules co-extracted from V. faba pod valves under these conditions remain poorly characterized. This information is relevant because persistent plant proteins may influence extract composition, stability, susceptibility to degradation, and downstream processing requirements. Here, we characterized co-extracted V. faba protein macromolecules in aqueous pod-valve extracts prepared in ultrapure water or naturally acidic media, including 2% Phyllanthus emblica, 5% Punica granatum, and 2% Ribes rubrum. Protein profiles were first evaluated by SDS-PAGE and subsequently analyzed by nanoflow liquid chromatography coupled to high-resolution tandem mass spectrometry (nLC-MS/MS). Protein identifications were complemented with Gene Ontology annotation and a descriptive semi-quantitative assessment of relative protein representation across extraction media. Chitinase was the most represented V. faba-assigned protein macromolecule across the extracts, with additional highly represented proteins including glucan endo-1,3-beta-D-glucosidase, pathogenesis-related proteins, and polyphenol oxidase A1. These co-extracted proteins are mainly associated with plant defense, stress responses, cell-wall remodeling, and oxidative processing, suggesting that they may be relevant for extract quality attributes during handling and storage. This study provides a compositional proteomic reference for the co-extracted protein macromolecules present in acidic aqueous extracts from V. faba pod valves, supporting future studies on extract stability, processing optimization, and the development of standardized plant-based preparations.

Vicia faba↗
PubMed2003

Compositional heterogeneity reflects partial dehydration in three-dimensional crystals of bacteriorhodopsin.

Absorption, fluorescence and excitation spectra of three-dimensional bacteriorhodopsin crystals harvested from a lipidic cubic phase are presented. The combination of the spectroscopic experiments performed at room temperature, controlled pH and full external hydration reveals the presence of three distinct protein species. Besides the well-known form observed in purple membrane, we find two other species with a relative contribution of up to 30%. As the spectra are similar to those of dehydrated or deionized membranes containing bacteriorhodopsin, we suggest that amino acid residues, located in the vicinity of the retinal chromophore, have changed their protonation state. We propose partial dehydration during crystallization and/or room temperature conditions as the main source of this heterogeneity. This assignment is supported by an experiment showing interconversion of the species upon intentional dehydration and by crystallographic data, which have indicated an in-plane unit cell in 3D crystals comparable to that of dehydrated bacteriorhodopsin membranes. Full hydration of the proteins after the water-withdrawing crystallization process is hampered. We suggest that this hindered water diffusion originates mainly from a closure of hydrophobic crystal surfaces by lipid bilayers. The present spectroscopic work complements the crystallographic data, due to its ability to determine quantitatively compositional heterogeneity resulting from proteins in different protonation states.

Bacteriorhodopsins↗
PubMed1988

A diffusion-adsorption model for the computation of the amount of hormone around a secreting cell, detected by the reverse hemolytic plaque assay.

The reverse hemolytic plaque assay enables the detection of secretion products from individual cells in cultures by visualizing the plaques formed after complement-mediated hemolysis around the secreting cells. However, the precise quantitation of the amount of secretion remains problematic. In this study we propose a computation model for estimating the spreading of the secreted molecules, based on the underlying processes of diffusion and antigen adsorption by immobilized antibodies. The translational diffusion coefficient of rat prolactin at 37 degrees C, determined by laser light scattering, was 9.89 x 10(-7) cm2/s. The time-dependent concentration distribution around a constantly secreting cell in a flat quasi infinite layer, was derived from the diffusion equation, using an analytical approach based on Laplace transformation. The relations between plaque size, incubation time and secretion level were expressed as a function of the threshold concentration of secretion product that can be detected and the effective diffusion coefficient, taking antigen adsorption into account. We obtained very good agreement between observed and predicted results for plaque formation by dispersed prolactin secreting cells of 14-day-old female rat pituitaries. This study confirms the validity of the assumptions underlying the reverse hemolytic plaque assay, provided that the cell density is low, the incubation time is moderately long and the concentration of specific antiserum is sufficiently high.

Adsorption↗
PubMedDate not supplied

Facial nerve axotomy in aged and young adult rats: analysis of the glial response.

With increasing age, there is a trend towards greater morbidity and injury extent with brain injury. Because several reports have suggested that microglia and astrocytes have an exacerbated response to brain injury in the aged, we set out to explore glial responses to facial nerve axotomy. This model was chosen because the glial responses are well-characterized in young rats and there is no perturbation of the blood-brain barrier (BBB). Immunohistochemistry was performed for glial fibrillary acidic protein (GFAP), leukocyte common antigen, type 3 complement receptor, and major histocompatability complex classes I and II. Quantitative analysis showed that age does not affect the glial response to axotomy in the lesioned facial nucleus; however, an aging-related contralateral effect with enhanced GFAP-labeling was observed. Interestingly, despite a lack of infiltrating neutrophils, a T cell influx was observed in both young and aged rats. Overall, these results suggest that neutrophil extravasion and BBB breakdown are underappreciated with regards to aging and injury exacerbation.

Aging↗
PubMed2001

An electrophysiological test of the effect of the temporal pattern of light adaptation on teleost H1 type horizontal cell plasticity.

The possible importance of the temporal pattern of photon delivery in light adaptation-induced physiological plasticity in the outer retina of carp was tested by intracellular recording. Steady and flicker (3 Hz) background adaptation was applied whilst recording chromatic voltage responses of H1 type horizontal cells (HCs) to 680 and 440 nm full-field test flashes (generating response amplitudes of V(r) and V(b), respectively). A third parameter V(b)/V(r) (B/R) was calculated as an indicator of the cells' short/long wavelength relative spectral contrast. Steady light adaptation increased V(r) and to a lesser extent V(b), and reduced B/R. Flicker adaptation also increased V(r) (by a similar amount), but, unlike steady adaptation, consistently decreased V(b). The reduction in B/R was statistically greater for flicker than for steady adaptation, although the former delivered half as many photons to the retina. These results suggest that the temporal pattern of light adaptation is indeed an important determinant of qualitative and quantitative aspects of plasticity induced in the outer retina, and complement earlier morphological findings. The effects are discussed in terms of dopamine and nitric oxide as underlying possible neurochemical control mechanisms.

Adaptation, Ocular↗
PubMed1977

Role of ribothymidine in mammalian tRNAPhe.

We have previously reported that mammalian tRNAsPhe from variation tissues contain different amounts of ribothymidine and that a uridine methylase from Escherichia coli can quantitatively convert these tRNAs to species that contain their full complement ofribothymidine at position 23 from the 3' terminus. The role of ribothymidine in mammalian tRNAs has now been investigated by studying the ability of several highly purified mammalian tRNAsPhe, differing only in their ribothymidine content, to support poly(U)-directed poly(Phe) synthesis under various conditions. Our results indicate that the ribothymidine content of mammalian tRNAPhe can be correlated with the ability of these tRNAs to functionin vitro in a low-magnesium (6 mM), ribosome wash factor-dependent, poly(U)-directed poly(Phe) synthesis system from rat liver. Specifically, the effect of increasing the ribothymidine content in a class C mammalian tRNA becomes manifest in an increased apparent maximum velocity for the overall synthesis of poly(Phe), while the apparent Michaelis constant (Km) remains essentially unchanged. It is postulated that the modifiednucleoside ribothymidine might be involved in the regulation of protein synthesis at the level of translation in mammalian liver.

Animals↗
PubMed2004

Glycerol-insensitive Arabidopsis mutants: gli1 seedlings lack glycerol kinase, accumulate glycerol and are more resistant to abiotic stress.

The aim of this study was to investigate the process of glycerol catabolism in germinating Arabidopsis seed. A genetic screen was performed to isolate glycerol-insensitive (gli) mutant seedlings. Three separate mutant loci were identified (gli1, gli2 and gli3). Of these, only gli1 is unable to utilise glycerol. Following germination, gli1 seedlings transiently accumulate glycerol derived from the breakdown of storage oil and are more resistant to hyperosmotic stress, salt stress, oxidative stress, freezing and desiccation. Enzyme assays revealed that gli1 lacks glycerol kinase activity. GLI1 mapped to chromosome 1 near the putative glycerol kinase gene NHO1. Mutations in this gene were identified in three independent gli1 alleles. A cDNA encoding GLI1 was cloned and its function was proven by complementation of an Escherichia coli glycerol kinase (glpK) deletion strain. Quantitative RT-PCR analysis showed that GLI1 is expressed in all tissues, but is transiently upregulated during early post-germinative growth and leaf senescence. These data show that glycerol kinase is required for glycerol catabolism in Arabidopsis and that the accumulation of glycerol can enhance resistance to a variety of abiotic stresses associated with dehydration.

Amino Acid Sequence↗
PubMed2003

The value of twins in dental research.

Due to recent advances in molecular genetics, studies of twins will continue to provide important insights into how genetic and environmental factors contribute to variation in human physical and behavioural traits and disorders. This review emphasizes that biometrical genetic studies of twins are particularly valuable in complementing and directing molecular approaches to facilitate the detection of quantitative trait loci. It also describes several other research models involving twins, apart from the traditional comparison of similarities in monozygotic (identical) and dizygotic (non-identical) pairs, that have the potential to provide new information in the future. Current knowledge about the genetic bases of common dental problems is summarized and future directions in dental research involving twins are outlined.

Dental Research↗
PubMed1994

An Azorhizobium caulinodans ORS571 locus involved in lipopolysaccharide production and nodule formation on Sesbania rostrata stems and roots.

Azorhizobium caulinodans ORS571 is able to nodulate roots and stems of the tropical legume Sesbania rostrata. An ORS571 Tn5 insertion mutant, strain ORS571-X15, had a rough colony morphology, was nonmotile, and showed clumping behavior on various media. When this pleiotropic mutant was inoculated on roots or stems of the host, no nodules developed (Nod-). Compared with the wild type, strain ORS571-X15 produced lipopolysaccharides (LPS) with an altered ladder pattern on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels, suggestive of a different O-antigen structure with a lower degree of polymerization. A cosmid clone, pRG20, that fully complemented all phenotypes of ORS571-X15 was isolated. With a 6-kb EcoRI subfragment of pRG20, clumping was relieved and nodulation was almost completely restored, but the strain was still nonmotile. LPS preparations from these complemented strains resembled the wild-type LPS, although minor quantitative and qualitative differences were evident. The sequence of the locus hit by the Tn5 in ORS571-X15 (the oac locus) revealed a striking homology with the rfb locus of Salmonella typhimurium, which is involved in O-antigen biosynthesis. The Tn5 insertion position was mapped to the oac3 gene, homologous to rfbA, encoding dTDP-D-glucose synthase. Biochemical assaying showed that ORS571-X15 is indeed defective in dTDP-D-glucose synthase activity, essential for the production of particular deoxyhexoses. Therefore, it was proposed that the O antigen of the mutant strain is devoid of such sugars.

Amino Acid Sequence↗
PubMed1982

Some aspects of porphyrin neurotoxicity in vitro.

Using a dissociated primary sensory neuron culture system, it is observed that some naturally occurring porphyrins produce dose-dependent neurotoxicity as measured by neuron death and by inhibition of the neurite outgrowth induced by Nerve Growth Factor (NGF). However, the porphyrin precursor delta-aminolevulinic acid (delta-ALA) is not toxic up to millimolar concentrations within a 30-h time period. Two synthetic porphyrins, tetraphenylporphine sulfonate (TPPS) and hematoporphyrin derivative (HPD), have also been shown to be toxic in vitro. Cultures and cocultures of isolated populations of neurons and glia of central and peripheral nervous system origin may prove advantageous in the study of porphyrin influences on the intact nervous system. This in vitro assay system can complement in vivo paradigms and may be useful for rapid quantitative screening for neurotoxicity of radiation sensitizers including the synthetic porphyrins and other chemotherapeutic agents.

Aminolevulinic Acid↗
PubMed2004

Chloroplast division site placement requires dimerization of the ARC11/AtMinD1 protein in Arabidopsis.

Chloroplast division is mediated by the coordinated action of a prokaryote-derived division system(s) and a host eukaryote-derived membrane fission system(s). The evolutionary conserved prokaryote-derived system comprises several nucleus-encoded proteins, two of which are thought to control division site placement at the midpoint of the organelle: a stromal ATPase MinD and a topological specificity factor MinE. Here, we show that arc11, one of 12 recessive accumulation and replication of chloroplasts (arc) mutants in Arabidopsis, contains highly elongated and multiple-arrayed chloroplasts in developing green tissues. Genomic sequence analysis revealed that arc11 contains a missense mutation in alpha-helix 11 of the chloroplast-targeted AtMinD1 changing an Ala at position 296 to Gly (A296G). Introduction of wild-type AtMinD1 restores the chloroplast division defects of arc11 and quantitative RT-PCR analysis showed that the degree of complementation was highly dependent on transgene expression levels. Overexpression of the mutant ARC11/AtMinD1 in transgenic plants results in the inhibition of chloroplast division, showing that the mutant protein has retained its division inhibition activity. However, in contrast to the defined and punctate intraplastidic localization patterns of an AtMinD1-YFP fusion protein, the single A296G point mutation in ARC11/AtMinD1 results in aberrant localization patterns inside chloroplasts. We further show that AtMinD1 is capable of forming homodimers and that this dimerization capacity is abolished by the A296G mutation in ARC11/AtMinD1. Our data show that arc11 is a loss-of-function mutant of AtMinD1 and suggest that the formation of functional AtMinD1 homodimers is paramount for appropriate AtMinD1 localization, ultimately ensuring correct division machinery placement and chloroplast division in plants.

Amino Acid Sequence↗
PubMed1976

Decrease and altered distribution of human T antigen on chronic lymphatic leukemia cells of T type, suggesting a clonal origin.

B- and T-cell markers were studied in a patient with chronic lymphocytic leukemia and erythroderma. The absence of immunoglobulin, complement receptor, and Fc receptor, and the presence of sheep erythrocyte receptor and T-cell antigen on the membrane of the leukemic cells classified them as thymus derived. Using quantitative microphotometric immunoautoradiography, surface antigen densities were measured at the cellular level with the following results: (1) The density of T-antigenic sites was less on leukemic cells compared to normal T lymphocytes. (2) The T-antigen densities of leukemic lymphocytes varied less from cell to cell forming a homogeneous peak in histograms. (3) An Ig density of normal B lymphocytes was demonstrated on the residual T-antigen-negative cells. The results were qualitatively confirmed by direct immunofluorescence and electron microscopy with peroxidase-labeled antibodies. Furthermore, the surface antigens were quantitative microcomplement fixation test which revealed reduced binding of anti-T-cell antibodies and complement, and no antiglobulin fixation on the leukemic lymphocytes. Since lymphocytes with normal T-antigen concentration could not be found among the leukemic T lymphocytes, a lack of normal T cells was assumed. The findings that there was a decrease and altered distribution of surface markers on chronic lymphatic leukemia cells of the B- and T-cell type are discussed as further arguments referring to their clonal origin.

Aged↗
PubMedDate not supplied

Preclinical trial of the antitumoral therapeutic effectiveness of some natural polyphenolic biopreparations.

We have assessed the antitumoral action of the POLYAS I and POLYAS II vegetal polyphenolic biopreparations--separated and purified from Asclepias syriaca leaves - in rats with various experimental tumoral lines. We studied the therapeutic effect of different doses on the tumor generation process and compared it with the experimental oncostatic action of several standard chemotherapeutic drugs of clinical use (thiotepa, methotrexate, melphalan and cyclophosphamide). In our experimental treatment with the bioactive polyphenolic agents, we have used various doses, both higher and lower than the dose that had conditioned the expression of their antitumoral action upon Guerin T-8 lymphotropic epithelioma and upon Walker 256 carcinosarcoma. We found the antineoplastic effectiveness of those aromatic biopreparations from phytomass to be dose-dependent. We compared the evaluation indices of the antitumoral pharmacodynamic effect we obtained in the treatment with the POLYAS biopreparations with those of reference cytostatic agents. The antitumoral potential of the new natural biopreparations is higher than, equal or close to that of the standard oncochemotherapeutic agents. Antitumoral effectiveness can be improved by an experimental manipulation of the therapeutic doses--which proves the existence of a dose-response relationship. POLYAS I and POLYAS II polyphenolic biopreparations are compatible in point of effectiveness with the standard cytostatic agents, a fact that we considered relevant for the characterization of the POLYAS I and POLYAS II vegetal extracts as potential antineoplastic agents. The quantitative preclinical evaluation of the specific pharmacodynamic effect will be complemented by the investigation of the new polyphenolic biopreparations therapeutic effectiveness in tumors with various degrees of development.

Animals↗
PubMed2003

Analysis of rat electroencephalogram during slow wave sleep and transition sleep using wavelet transform.

The dynamic features of rat EEGs collected during slow wave sleep (SWS) and transition sleep (TS) were investigated in both time and frequency domains using wavelet transform based on multi-resolution signal decomposition. EEGs of freely moving rats were recorded with implanted electrodes and then decomposed into four components of delta, theta, alpha and beta using wavelet transform. The power and power percentage of each component were calculated as functions of time. In SWS EEGs, the results showed that there existed as much as 26.2% +/- 7.7% time duration in which the delta power percentage was less than 50%. In addition, the powers of other three components in small delta EEGs were significantly larger than those in large delta EEGs. This result revealed a reciprocal relationship between delta oscillation and spindle oscillation. Comparatively, the conventional method of FFT based power spectrum could only show a delta power-dominating (70.6% +/- 6.4%) spectrum of SWS EEGs. In the non-stationary TS EEG, spindle and non-spindle segments were distinguished based on the wavelet components of theta and alpha, and then the average duration of the spindles was estimated. In conclusion, the wavelet transform may be useful in developing novel quantitative time-frequency measures of sleep EEGs as valuable complements of conventional FFT method to analyze the transient changes in sleep EEGs induced by physiological, pathological or pharmacological conditions.

Animals↗
PubMed1977

[Chemotaxis and phagocytosis of polymorphonuclear leukocytes in malnourished children].

Chemotactic activity of neutrophil polimorphonuclear cells, liberation of chemotactic factors by plasma proteins and phagocytic function of PMN cells by nitroblue tetrazolium reaction were evaluated in 20 malnourished children (from grade 1 through grade III) and in 20 normal children with similar age and sex, without any apparent infection. Also quantitative determination of immunoglobulins A, G and M and C3 complement fraction concentration in serum was made. Chemotactic and phagocytic activity were normal. Serum levels of Igs and C3 complement were within the lower limits of the normal range.

Chemotaxis, Leukocyte↗
PubMed1978

[Experimental studies on the affinity of Toxoplasma gondii to various organs of mice (author's transl)].

In response to their alleged "uterus affinity" the organotropism of various Toxoplasma strains was investigated in the female mouse. Using quantitative histological (immunofluorescence) and serological (Sabin-Feldman-dye test, complement fixation test), we examined the brain, heart, lung, spleen, striated muscle, uterus and ovaries. The following results were obtained: All four of the Toxoplasma strains (ALT, DX, WEISS, GAIL) showed a definite neurotropism. Located in the brain were one hundred times as many cysts as in the sexual organs and ten times as many as in the reamining organs. The uterus and ovary show a low susceptibility, invasion rarely occuring. An "uterus affinity" could not be confirmed. All four Toxoplasma strains showed the same affinity for the various organs. The strain ALT showed the most virulence and formed the most cysts.

Animals↗
PubMed1993

Ischemia-reperfusion injury.

Ischemia followed by reperfusion of the rat hind limb resulted in local evidence of injury, as reflected in increased vascular permeability and hemorrhage in skeletal muscle as well as distant organ injury, as reflected by increased vascular permeability and hemorrhage in lung. These changes were proportional to the duration of reperfusion and were associated with neutrophil accumulation in tissue, as quantitated by myeloperoxidase (MPO) content. There was corresponding evidence of complement depletion and increases in plasma IL-1 and IL-6. On the basis of interventional approaches, limb and lung vascular injury was neutrophil and complement dependent and was attenuated by treatment with antioxidants. Products of L-arginine were involved in the development of vascular injury since antagonists of L-arginine were protective. Based on the use of blocking antibodies, the cytokines TNF alpha and IL-1 were also involved in the development of tissue injury. Finally, both LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) beta 2 integrins were required as well as the endothelial adhesion molecules E-selectin and ICAM-1. Protective interventions were more protective that both local and remote organ injury following ischemia-reperfusion is in lung than in skeletal muscle. There were, in general, parallel effects when tissue protection was related to reduction in MPO content. These data suggest dependent on toxic oxygen and L-arginine products of neutrophils, the accumulation of which can be linked to cytokines (TNF alpha, IL-1), beta 2 integrins and endothelial adhesion molecules.

Animals↗