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At least 1,369 records · Page 76Linked to original sources
PubMed2006

[Extraction and salting-out purification of alpha-galactosidase and beta-glucosidase from fresh roots of Rehmannia glutinosa].

OBJECTIVE: To extract and preliminarily purify alpha-galactosidase and beta-glucosidase from the fresh roots of Rehmannia glutinosa. METHODS: With the enzyme activity as a criterion, the best procedure of extraction was selected though orthogonal design method, and the desired saturation of ammonium sulfate in two-step salting-out was settled by gradient sedimentation of root extract according to enzyme activity and protein content. RESULTS: Temperature and solvent volume affect the extraction of alpha-galactosidase significantly, while solvent type to beta-glucosidase. Therefore the procedure for extracting two enzymes was decided as mixing comminuted fresh root with 3 times phosphate buffer, and placing the mixture in refrigeratory at 4 degrees C for 4 hours, and then obtaining the enzyme liquid by centrifuging at 4 degrees C. 30% and 60% saturation was defined as the lower and upper point for two-step ammonium sulfate salting-out of the two enzymes. CONCLUSION: alpha-Galactosidase and beta-glucosidase exist in the fresh roots, and can be preliminarily purified through two-step salting-out.

Molecular Weight↗
PubMed1979

Procedure of RNA extraction which does not extract DNA and proteins from nervous tissue cells.

Several schemes of acidic extraction of RNA taken from biochemical or cytochemical literature were compared by means of ultraviolet and visible cytospectrophotometry. Basing on the data obtained an extraction scheme has been recommended which consists in the treatment of nervous tissue sections with 16 per cent perchloric acid at 4 degrees C for 48 h. This extraction has been shown to extract completely cellular RNA without extracting DNA and proteins from the nervous tissue cells. Using this scheme, ultraviolet cytospectrophotometry of neurons and glial cells was performed twice, before and after the selective RNA extraction, which enabled a calculation of RNA concentration by the difference of the absorption values. In mice, after 3 h-swimming, and in cats, after 2-week daily injections of adrenaline, a number of quantitative and qualitative RNA changes were found out in nerve and glial cell of mouse spinal cord and cat sympathetic ganglion with the aid of the recommended scheme of RNA extraction.

Animals↗
PubMed1995

Extraction of water-soluble vitamins from pharmaceutical preparations using AOT (sodium di-2-ethylhexyl sulfosuccinate)/pentane reversed micelles.

Reversed micelles can be used to concentrate water-soluble materials in the water pool. In this study, the extraction of water-soluble vitamins into reversed micelles was attempted, and a flow system was used to determine the time-course of the vitamin extraction. The efficiency of extraction was strongly affected by the extraction temperature and the concentration of reversed micelles, and the selectivity depended on the size of micelles. Water-soluble vitamins could be efficiently and rapidly extracted. The selective extraction of a model mixture of vitamins from pharmaceutical preparations was also attempted. Moreover, the usefulness of the proposed method for the determination of vitamins in various commercial tablets was also demonstrated. Using of this method, the surfactant remains mixed with the extracted compounds, and so we attempted to remove the surfactant from the extract by supercritical fluid extraction. Supercritical carbon dioxide containing 7.5% ethanol as entrainer was found to be the most efficient solvent for removing residual surfactant from the extract.

Ascorbic Acid↗
PubMed2003

[Study on extraction process of zhanjin ruji].

OBJECTIVE: To select the optimum extraction process of Zhanjin Ruji. METHOD: To observe influence of extraction time upon the extraction rate of volatile oil, the orthogonal test was adopted to observe the extraction process by alcohol from the extraction rate and content of the total saponins in Radix Notoginseng. RESULT: The three kinds of herbs including Radix Angelicae Sinensis, Resina Olibani and Myrrha were extracted with water for 3 hours, 95% of volatile oil can be distilled. The three kinds of herbs including Radix Notoginseng, Herba Lycopodii and Radix Gentianae Macrophyllac were extracted by alcohol. Four factors such as alcohol concentration(A), extraction times(B), extraction time(C), and solvent amount(D), had not significant effect on the content of total saponins in Radix Notoginseng in herbal extraction, but factor A and B had significant effect on the extraction rate. The optimum extraction process was as follows extracted with 5 times the amount of the solvent volum 60% alcohol for 3 times and with each time for 1 hour. Three times experiments showed that the extraction rate was 26.5% and the content of the total saponins in Radix Notoginseng was 17.28% mg.g-1. CONCLUSION: The above experimental results can provide experimental basis for deciding the extraction process of Zhanjin Ruji.

Angelica sinensis↗
PubMed1985

Trace analysis by gas chromatography/mass spectrometry (GC/MS) using a tandem double-focusing/quadrupole instrument.

Analysis for oestradiol bis-tert-butyldimethylsilyl ether by gas chromatography/mass spectrometry (GC/MS) with selected reaction monitoring ([M]+.----[M-C4H9]+) using a tandem double-focusing/quadrupole instrument gave a detection limit below 10 pg. During analyses of a plasma extract, the selectivity of detection was superior to conventional selected ion monitoring. A parent ion resolution of 5000 was used to eliminate detection of all components but the chosen analyte.

Estradiol↗
PubMed2000

Post-transcriptional regulation of urokinase mRNA. Identification of a novel urokinase mRNA-binding protein in human lung epithelial cells in vitro.

We sought to determine if urokinase expression is regulated at the post-transcriptional level in cultured lung epithelial cells. We also sought to determine if differences in urokinase expression by cultured human lung carcinoma and non-malignant lung epithelial subtypes were attributable to post-transcriptional regulatory mechanisms. Urokinase was expressed by phenotypically diverse lung carcinoma cell lines as well as non-malignant small airway epithelial cells and bronchial epithelial cells. Using gel mobility shift and UV cross-linking assays, we identified a 30-kDa urokinase mRNA-binding protein that selectively bound to a 66-nucleotide protein-binding fragment of urokinase mRNA. The urokinase mRNA-binding protein is found in the cytosolic but not nuclear extracts of non-malignant lung epithelial cells; whereas, it is found in the nuclear but not cytosolic extracts of selected malignant carcinoma-derived cells that express relatively large amounts of urokinase. Chimeric beta-globin/urokinase cDNA containing the urokinase mRNA-binding protein binding sequence destabilized otherwise stable beta-globin mRNA. Our results demonstrate that urokinase gene expression in lung epithelial and lung carcinoma-derived cells is regulated at the post-transcriptional level. The mechanism involves an interaction between a 66-nucleotide sequence of the urokinase mRNA 3'-untranslated region with a newly recognized urokinase mRNA-binding protein to regulate urokinase mRNA stability.

Base Sequence↗
PubMed1995

Active-oxygen scavenging activity of plant extracts.

To find antioxidative compounds present in plants, 65 types of plant extract were tested using the neotetrazolium method for evidence of superoxide anion-scavenging effects and 7 plant extracts were selected for further investigation. The activity of active-oxygen scavengers such as superoxide anion radicals, hydroxyl radicals, singlet oxygens and lipid peroxides in the 7 plant extracts (Aeseclus hippocastanum L., Hamamelis virginiana L. Polygonum cuspidatum Sieb., Quercus robur L., Rosemarinous officinalis L., Salvia officinalis L. and Sanguisorba officinalis L.) was examined in detail by both ESR spin-trapping and malondialdehyde generation. Furthermore, the active-oxygen scavenging activity of these plant extracts was evaluated using a murine dermal fibroblast culture system. Both Aeseclus hippocastanum L. and Hamamelis virginia L. were found to have strong active-oxygen scavenging activity of and protective activity against cell damage induced by active oxygen. Both Aeseclus hippocastanum L. and Hamamelis virginiana L. are proposed as potent plant extracts with potential application as anti-aging or anti-wrinkle material for the skin.

Animals↗
PubMed2001

Response of herb processing workers to work-related airborne allergens.

A group of 51 herb processing workers employed in a big herb processing facility located in eastern Poland were examined by the skin and precipitin tests with, respectively, 4 and 17 extracts of microorganisms associated with organic dusts. Out of this number, 32 workers were examined by the skin test with 7 extracts of selected herbs processed in the facility. All the subjects were asked about the occurrence of work-related symptoms. 32 healthy office workers were examined with microbial extracts as a reference group. The herb processing workers showed a high proportion of early skin reactions (after 20 min) to the extract of Gram-negative bacterium Alcaligenes faecalis (41.2%), significantly higher compared to the reference group (p<0.01). At all time intervals (20 min, 8 hrs, 24 hrs), the workers responded with a high frequency to the extract of Bacillus subtilis (respectively 72.5%, 64.7%, and 15.7%), significantly greater compared to the reference group (respectively p<0.001, p<0.001, and p<0.05). No significant differences were found between the groups of herb processing workers and referents in skin response to the extracts of Streptomyces albus and Alternaria alternata and, except for the extract of Pantoea agglomerans, in the frequency of positive precipitin reactions to microbial antigens. In the skin test with herb extracts, the highest response among workers were caused by the extracts of chamomile flowers and nettle leaves which evoked 40-65% of positive skin reactions at all time intervals. 39 out of 51 interviewed herb processing workers (76.5%) reported the occurrence of work-related general, respiratory and skin symptoms. The positive skin reactions occurred more frequently among symptomatic workers which suggests that the specific immunologic response might be implicated in etiopathogenesis of work-related symptoms in examined workers. However, in most cases the differences did not attain a significance level which indicates that there is no direct relationship between a positive immunologic response and the appearance of symptoms caused by occupational exposure to herb dust, and that most probably a considerable part of these symptoms might be also due to non-specific immunologic and/or toxic mechanisms.

Adult↗
PubMed1986

Selective effects of skeletal muscle extract fractions on motoneuron development in vitro.

In vivo labeling of motoneurons with retrogradely transported wheat germ agglutinin, and in situ staining of cholinergic neurons with a monoclonal antibody against CAT, have been used as methods to identify motoneurons in cultures of dissociated 14 d embryonic rat ventral spinal cord. With these two different labeling techniques, we demonstrate that skeletal muscle extracts maintain motoneuron survival, and induce motoneuron morphologic and cholinergic differentiation in vitro. Further, we show that several partially purified muscle extract-derived proteins separately augment each of these specific parameters of motoneuron development. A 55,000 Da neutral glycoprotein specifically induces both ACh synthesis and motoneuron-selective process outgrowth and elongation, while a 1200-1500 Da peptide selectively augments both apparent motoneuron survival and ACh synthesis. A third trophic agent, a 33,000-35,000 Da acidic glycoprotein, induces process outgrowth in both motoneurons and nonmotoneurons of the ventral spinal cord, but has no effect on ACh synthesis.

Acetylcholine↗
PubMed2002

Toward a model for lexical access based on acoustic landmarks and distinctive features.

This article describes a model in which the acoustic speech signal is processed to yield a discrete representation of the speech stream in terms of a sequence of segments, each of which is described by a set (or bundle) of binary distinctive features. These distinctive features specify the phonemic contrasts that are used in the language, such that a change in the value of a feature can potentially generate a new word. This model is a part of a more general model that derives a word sequence from this feature representation, the words being represented in a lexicon by sequences of feature bundles. The processing of the signal proceeds in three steps: (1) Detection of peaks, valleys, and discontinuities in particular frequency ranges of the signal leads to identification of acoustic landmarks. The type of landmark provides evidence for a subset of distinctive features called articulator-free features (e.g., [vowel], [consonant], [continuant]). (2) Acoustic parameters are derived from the signal near the landmarks to provide evidence for the actions of particular articulators, and acoustic cues are extracted by sampling selected attributes of these parameters in these regions. The selection of cues that are extracted depends on the type of landmark and on the environment in which it occurs. (3) The cues obtained in step (2) are combined, taking context into account, to provide estimates of "articulator-bound" features associated with each landmark (e.g., [lips], [high], [nasal]). These articulator-bound features, combined with the articulator-free features in (1), constitute the sequence of feature bundles that forms the output of the model. Examples of cues that are used, and justification for this selection, are given, as well as examples of the process of inferring the underlying features for a segment when there is variability in the signal due to enhancement gestures (recruited by a speaker to make a contrast more salient) or due to overlap of gestures from neighboring segments.

Attention↗
PubMed1999

Selective trace enrichment by immunoaffinity capillary electrochromatography on-line with capillary zone electrophoresis - laser-induced fluorescence.

Limited by the lack of a sensitive, universal detector, many capillary-based liquid-phase separation techniques might benefit from techniques that overcome modest concentration sensitivity by preconcentrating large injection volumes. The work presented employs selective solid-phase extraction by immunoaffinity capillary electrochromatography (IACEC) to enhance detection limits. A model analyte, fluorescein isothiocyanate (FITC) biotin, is electrokinetically applied to a capillary column packed with an immobilized anti-biotin-IgG support. After selective extraction by the immunoaffinity capillary, the bound analyte is eluted, migrates by capillary zone electrophoresis (CZE), and is detected by laser-induced fluorescence. The column is regenerated and reused many times. We evaluate the performance of IACEC for selective trace enrichment of analytes prior to CZE. The calibration curve for FITC-biotin bound versus application time is linear from 10 to 300 seconds. Recovery of FITC-biotin spiked into a diluted urinary metabolites solution was 89.4% versus spiked buffer, with a precision of 1.8% relative standard deviation (RSD).

Buffers↗
PubMed2005

[Study on the extraction process for cannabinoids in hemp seed oil by orthogonal design].

OBJECTIVE: To select the optimum extracting procedure for cannabinoids from hemp seed oil. METHODS: The optimum extracting procedure was selected with the content of cannabinol and delta9-tetrehydrocannabinol from hemp seed oil by orthogonal test design. We have examined three factors that may influence the extraction rate: the time of extraction, the times of extraction and the amount of methanol. RESULTS: The optimum extraction condition was adding 5 ml, two times amount of methanol into hemp seed oil for 15 min. CONCLUSION: The above extraction process gave the most rational, stable, feasible and satisfactory results. The method is convenient.

Cannabinoids↗
PubMed1983

A generalized extraction-TLC procedure for identification of drugs.

A combination of liquid-liquid extraction and thin-layer chromatography permits rapid identification of a large variety of drugs in pharmaceutical or street dosage forms, or in biological materials. The system utilizes selective pH extraction combined with internal standards. Limits of sensitivity are in the submicrogram level. The procedure is rapid and requires minimal equipment and training of personnel. It can be supplied in toxicology involving both clinical and forensic demands.

Chromatography, Thin Layer↗
PubMed2006

Novel biphasic separations utilising highly selective molecularly imprinted polymers as biorecognition solvent extraction agents.

Molecularly imprinted polymers (MIPs) represent a class of artificial receptors that promise an environmentally robust alternative to naturally occurring biorecognition elements of biosensing devices and systems. However, in general, the performance of conventional MIPs in aqueous environments is poor. In the study reported here, this limitation has been addressed by the novel application of MIPs as a solvent extraction solid phase in a biphasic solvent system. This paper describes a previously unreported use of MIPs as solvent extraction reagents, their successful application to aqueous sample media and the opportunities for utilisation of this unique system in novel biosensing and separation procedures. This study demonstrates the development of a novel biphasic solvent system utilising MIP in the extracting phase to enhance both efficiency and selectivity of a simple two phase liquid extraction. Monodisperse propranolol imprinted polymer microspheres [p(divinylbenzene-co-methacrylic acid)] were prepared by precipitation polymerisation. Initially, the affinity of the polymers for (R,S)-propranolol was assessed by established techniques whereby the MIP demonstrated greater affinity for the template than did the non-imprinted control polymer (NIP). Importantly, MIP performance was also assessed using the novel dual solvent system. The depletion of (R,S)-propranolol from the aqueous phase into the polymer containing organic phase was determined. When compared to control extractions containing no polymer the presence of MIP in the extracting solvent phase resulted in an increased extraction of (R,S)-propranolol from the aqueous phase. Importantly, this extraction was significantly greater in the presence of MIP when compared to NIP. This unique principle generates opportunities for MIP based extractions and chemical enrichments in industrial applications, offering commercial, ecological and practical advantages to traditional solvent extraction techniques. The technique is readily transferable to analytical microsystems utilising MIP recognition elements generating promising opportunities for MIP based sensing of aqueous sample media.

Biosensing Techniques↗
PubMed2003

Capillary extractors for "negligible depletion" sampling of benzene, toluene, ethylbenzene and xylenes by in-tube solid-phase microextraction.

The suitability of "capillary extractors" is demonstrated for the "negligible depletion" extraction of benzene, toluene, ethylbenzene and xylenes in a clean-water matrix. Extraction set-up and major extractor parameters (length, internal diameter, and film thickness) are chosen to allow rugged analysis by GC with flame ionization detection. With the selected negligible extraction conditions, the efficiency for every consecutive extraction is about 2-3% of the dissolved amount.

Benzene↗
PubMed1996

Mechanism of peptide separations by solid phase extraction capillary electrophoresis at low pH.

A device for on-line extraction and concentration of peptides from a dilute sample matrix prior to direct capillary electrophoretic analysis is described. The technique, termed solid phase extraction capillary electrophoresis (SPE-CE), can facilitate analysis of peptides in the low nanograms per milliliter range. Peptides from a sample matrix are adsorbed on a reversed phase resin (C-8 or C-18) cartridge in-line with an uncoated fused-silica capillary and subsequently released for free zone electrophoresis by injection of an organic elutant. Unlike previous designs and commercially available packed-inlet capillaries, the device is easily constructed from common laboratory materials and is applicable to a wide range of conventional instrumentation and methods. This device and method has been developed for use in our laboratory as a stand-alone preparative technique, specifically to provide a second-dimensional orthogonal separation of biologically derived HPLC fractions of peptides in a single analysis. To this end, extensive effort was required in both device construction and method development to attain the successful separations which are reported in this study. Extractions of dilute peptide mixtures from sample injections exceeding, but not limited to, 20 times (48 microL) the capillary volume with apparent recovery greater than 80% are shown. The selectivity of extraction of individual components of a very dilute peptide mixture (31 ng/mL with 280 microL of sample injected) is presented. The ability to efficiently extract the individual peptides from the sample was found to be concentration-dependent for the individual peptide components over a 1600-field dilution of a common calibration mixture of nine model peptides. Varying the injected volume of elution buffer demonstrated the importance of minimizing the amount of buffer used to desorb peptides to maximize the resolution of individual peptides. This study highlights implementation for direct SPE-CE for peptide analysis and discusses for SPE tip-induced mechanism through which reversal in electoosmotic flow occurs.

Amino Acid Sequence↗
PubMed2000

The eukaryotic promoter database (EPD).

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes a description of the initiation site mapping data, exhaustive cross-references to the EMBL nucleotide sequence database, SWISS-PROT, TRANSFAC and other databases, as well as bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. WWW-based interfaces have been developed that enable the user to view EPD entries in different formats, to select and extract promoter sequences according to a variety of criteria, and to navigate to related databases exploiting different cross-references. The EPD web site also features yearly updated base frequency matrices for major eukaryotic promoter elements. EPD can be accessed at http://www.epd.isb-sib.ch

Database Management Systems↗
PubMed2004

The Eukaryotic Promoter Database EPD: the impact of in silico primer extension.

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters, experimentally defined by a transcription start site (TSS). There may be multiple promoter entries for a single gene. The underlying experimental evidence comes from journal articles and, starting from release 73, from 5' ESTs of full-length cDNA clones used for so-called in silico primer extension. Access to promoter sequences is provided by pointers to TSS positions in nucleotide sequence entries. The annotation part of an EPD entry includes a description of the type and source of the initiation site mapping data, links to other biological databases and bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. Web-based interfaces have been developed that enable the user to view EPD entries in different formats, to select and extract promoter sequences according to a variety of criteria and to navigate to related databases exploiting different cross-references. Tools for analysing sequence motifs around TSSs defined in EPD are provided by the signal search analysis server. EPD can be accessed at http://www.epd. isb-sib.ch.

Animals↗