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  • Analytical Chemistry and Spectroscopy  (17)
  • Capillary electrophoresis  (4)
  • Amphibian  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Formation of the amphibian grey crescent: Effects of colchicine and cytochalasin B (1978)
    Springer
    Development genes and evolution 185 (1978), S. 99-104 
    Details
    ISSN: 1432-041X
    Keywords: Amphibian ; Grey crescent ; Colchicine ; Cytochalasine B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of colchicine and cytochalasin B on grey crescent formation in frog (Rana pipiens) and toad (Bufo arenarum) eggs were determined. Colchicine prevented the appearance of the grey crescent, but this inhibition was not due to the absence of an aster. Cytochalasin B did not inhibit grey crescent formation, nor did it inhibit certain activation events such as cortical granule breakdown or cortical contraction. Cytochalasin B caused a detachment of the cortex from the cytoplasm and induced the formation of a morphological grey crescent in non-activated eggs. The results suggest that microtubules may play several roles in grey crescent formation and that a change in the attachment of the cortex to the cytoplasm may also be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848218
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  • 2
    Electronic Resource
    Electronic Resource
    Ultraviolet light inhibits grey crescent formation on the frog egg (1980)
    Springer
    Development genes and evolution 189 (1980), S. 73-76 
    Details
    ISSN: 1432-041X
    Keywords: Ultraviolet irradiation ; Amphibian ; Grey crescent ; Embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Work by others has shown that ultraviolet (UV) irradiation of the vegetal half of the uncleaved frog egg causes defects in neural development. We find that the earliest effect of irradiation ofRana pipiens eggs is to prevent grey crescent formation, the first indication of dorso-ventral polarization of the egg. The UV effect on the grey crescent and on neural development shows similarities in timing, dose-responses, and reversal by cold. We suggest that the UV effect on neural morphogenesis may be caused by the inhibition of cortical-cytoplasmic movement involved in grey crescent formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848569
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  • 3
    Electronic Resource
    Electronic Resource
    Capillary gas chromatography/mass spectrometry of cholesteryl esters with negative ammonia chemical ionization (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 131-140 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mixtures of both synthetic and naturally occurring (human plasma) cholesteryl esters have been examined by capillary gas chromatography/mass spectrometry (GC/MS). A magnetic sector mass spectrometer was used and a variety of ionization modes were assessed with a view to obtaining structural information on intact cholesteryl esters. By employing ammonia as reagent gas, with negative ion scanning, spectra were produced from which the nature of steryl and fatty acyl moieties could be readily deduced. Analyses were performed at an ion source temperature of 300°C in order to maintain the integrity of the gas chromatographic profile. The technique described is of general use for the GC/MS analysis of steryl esters, particularly in conjunction with magnetic sector instruments.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140307
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  • 4
    Electronic Resource
    Electronic Resource
    Application of electrospray ionization mass spectrometry with maximum-entropy analysis to allelic ‘fingerprinting’ of major urinary proteins (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 882-886 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Mixtures of a specific group of proteins, the major urinary proteins (MUPs), believed to have a role in odorant binding, have been analysed by electrospray ionization mass spectrometry. The data obtained from conventional transformed electrospray data confirm that the molecular weights of the protein mixtures, deduced from published sequences, lie in the molecular weight range 18600 to 19 000 Da. Application of maximum-entropy analysis to the raw electrospray data has confirmed a heterogeneity in MUP composition, consistent with allelic similarities (and differences) between the different mouse strains. This work demonstrates the use of maximum entropy in the assessment of protein content and in the subsequent resolution enhancement of naturally occurring protein mixtures containing components of closely similar molecular mass.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290071005
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  • 5
    Electronic Resource
    Electronic Resource
    The determination of sequence information in homologously related proteins by mass spectrometry (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 269-273 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An azurin, a small respiratory copper protein from the bacterium Pseudomonas fluorescens biotype G, has been studied by mass spectrometry to determine sequence information. The study of homologously related proteins by mass spectiometry is particularly attractive, since the correct nature of major parts of the deduced sequences can be confirmed by comparison with the sequences of the protein from related organisms. An oxidized tryptohan residue has been identified amongst the products from a cyanogen bromide digest of this wild type azurin. In the same digest, a product is also found to arise from cleavage of the peptide chain at the C-terminal side of the same tryptophan residue. These results are rationalized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010411
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  • 6
    Electronic Resource
    Electronic Resource
    A novel inexpensive device for the electrochemical generation of metallic emitters for field desorption (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 52-54 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Details for the construction of a novel, inexpensive device for the electrochemical generation of metallic emitters for field desorption mass spectrometry are described. Use of the device for the generation of cobalt and nickel emitters is demonstrated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200040107
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  • 7
    Electronic Resource
    Electronic Resource
    Detection of nucleotide bases in ancient seeds using gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 503-508 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Nucleic acid extracts from 1400-year-old radish seeds recovered from excavations at Qasr Ibrim, Upper Egypt, have been analysed by gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry. tert-Butyldimethyisilyl derivatives of the purine and pyrimidine bases were prepared, after treatment of the nucleic acid extracts with concentrated formic acid. Under electron ionization these derivatives yield prominent [M-57]+ ions that were found to be of value for use in analyses employing selected-ion monitoring and product-ion studies. These two techniques were used in the sensitive and selective detection of nucieotide bases in crude extracts of ancient seeds. The results obtained were supported by complementary analyses of hydrolysates of ancient nucleic acids and authentic bases by means of retention time and spectral comparisons. This work demonstrates for the first time that mass spectrometry can be used in the direct chemical examination of nucleotide bases in ancient materials. This analytical approach is currently being used to address questions regarding the possible chemical (diagenetic) changes occurring in the nucleic acids of ancient biological material.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080702
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  • 8
    Electronic Resource
    Electronic Resource
    Local alteration of cortical actin in Xenopus eggs by the fertilizing sperm (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 35 (1993), S. 69-75 
    Details
    ISSN: 1040-452X
    Keywords: Amphibian ; Microfilaments ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rhodamine phalloidin (Rph) staining was used to examine the microfilament organization of the Xenopus laevis egg cortex during the early stages of fertilization. Unactivated eggs possessed a cytochalasin B (CR)-insensitive Rph-stained matrix that was reorganized upon egg activation and diminished in the presence of CB. Xenopus laevis sperm caused a temporary local increase in Rph staining on the Xenopus cortex. In CB-treated eggs, the local increases of cortical Rph staining later changed to a Rph-free area. These temporary local increases of cortical Rph staining were also observed when Notophthalmus viridescens sperm fertilized Xenopus and Rana pipiens eggs, and were followed by the appearance of concentric rings of stained and unstained areas. Our data suggest that Xenopus and Notophthalmus sperm have activities that can both organize and disrupt the cortical filamentous actin of the Xenopus egg. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080350112
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  • 9
    Electronic Resource
    Electronic Resource
    High-performance liquid chromatography/mass spectrometry with thermospray lonization of free ecdysteroids (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 477-481 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: High-performance liquid chromatography/mass spectrometry (HPLC/MS) with thermospray ionization has been applied to the analysis of free ecdysteroids (polyhydroxylated steroids that serve as arthropod moulting hormones). Of a range of analytical conditions that were tested, optimum results were obtained by the use of re versed-phase HPLC using a methanol + water mixture containing 0.1 M ammonium acetate. The positive-ion spectra of ecdysteroids showed pseudo-molecular ions, [M + H]+, and fragment ions corresponding to the sequential losses of hydroxyl groups. The [M + H - H2O]+ and [M + H - H2O]+ ions were the most abundant for all the compounds tested. Ecdysteroids bearing a C-20 hydroxyl group (e.g. 20-hydroxyecdysone) showed ions characteristic of cleavage of the side-chain from the steroid nucleus. This mode of fragmentation was much less obvious in the case of ecdysteroids lacking C-20 hydroxylation (e.g. ecdysone). Full-scan mass spectra were readily obtained from 1 μg of free ecdysteroids, while a limit of detection of 5 ng (signal-to-noise ratio 3) was attained in the selected-ion monitoring mode. The application of HPLC/MS to the study of ecdysteroids in biological materials is demonstrated by the analysis of extracts of newly laid eggs of the desert locust (Schistocerca gregaria) and pupae of the cotton leafworm (Spodoptera litoralis).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290070615
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  • 10
    Electronic Resource
    Electronic Resource
    Evaluation of copper-based electrodes for the analysis of aminoglycoside antibiotics by CE-EC (1997)
    Weinheim : Wiley-Blackwell
    Electroanalysis 9 (1997), S. 1145-1151 
    Details
    ISSN: 1040-0397
    Keywords: Copper electrode ; Antibiotics ; Capillary electrophoresis ; Aminoglycosides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aminoglycoside antibiotics including gentamicin, bekanamycin, tobramycin, lincomycin, neomycin, kanamycin, and ribostamycin have been determined by CE-EC with copper clectrodes. Both copper wall-jet electrodes (WJEs) and copper on-capillary electrodes (OCEs) were evaluated. The OCEs provided μM detection limits, superior stability and reproducibility (2-3% relative standard deviation in oxidation current), and a simple instrumental set-up without the need for capillary/electrode alignment. The analytical capabilities of the Cu-OCE were examined, following the optimization of CE conditions, for the seven aminoglycosides above; and the practical utility of this approach was demonstrated through the determination of aminoglycoside antibiotics in three pharmaceutical preparations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140091502
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