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  • Articles  (35)
  • Springer  (31)
  • Blackwell Publishing Ltd  (4)
  • 2000-2004  (13)
  • 1995-1999  (21)
  • 1935-1939
  • 1920-1924  (1)
  • 1905-1909
  • Biology  (35)
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  • Articles  (35)
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  • 1
    Electronic Resource
    Electronic Resource
    RECOVERY OF ESCHERICHIA COLI O157:H7 FROM FIBER OPTIC WAVEGUIDES USED FOR RAPID BIOSENSOR DETECTION (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of rapid methods and automation in microbiology 10 (2002), S. 0 
    Details
    ISSN: 1745-4581
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Consumption of ground beef has been implicated in the majority of outbreaks of disease from Escherichia coli O157:H7. There is a great need for rapid, sensitive, and specific microbial detection and isolation methods for the detection and recovery of pathogens such as E. coli O157:H7. Evanescent wave, fiber optic biosensors are an innovative, cutting-edge technology with the potential to meet such a need. Food pathogens such as E. coli O157:H7 can be detected in minutes using the biosensor assay rather than days using conventional methods. The biosensor assay is sensitive and presently has the ability to directly detect 102 CFU of E. coli O157:H7 in E. coli O157:H7-seeded PBS or ground beef. In this study, it was determined that once the pathogen had been positively identified, it could then be recovered by culturing the cells captured on the waveguide used in the biosensor assay. E. coli O157:H7-seeded PBS or ground beef samples were assayed using an evanescent wave, fiber optic biosensor. After a positive identification on the biosensor, the waveguide was added to modified LB medium supplemented with 10 μg/mL acriflavin (mLB) and incubated at 42C for a minimum of 4 h followed by selection on Rainbow O157 agar incubated 16 to 18 h at 37C. E. coli O157:H7 was confirmed using agglutination with E. coli O157:H7 antiserum. It was possible to recover E. coli O157:H7 colonies in E. coli O157:H7-seeded PBS or ground beef when 1 mL samples containing at least 2.0 × 103 CFU of E. coli O157:H7 had been injected into the biosensor. It took only 24 h to detect the target pathogen, recover the pathogen from the sample, and grow isolated colonies. This total time included sample preparation, detection, enrichment culture, and growth of cells to produce isolated colonies on a selective and differential medium. The identification of isolated colonies was then quickly confirmed using slide agglutination with the appropriate antiserum. This method significantly improved the speed of the confirmation of the presence of the pathogen and of the isolation of the pathogen, from 4 days using conventional methods to one day using the biosensor assay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4581.2002.tb00015.x
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  • 2
    Electronic Resource
    Electronic Resource
    Photoreceptors and signals in the photoperiodic control of development (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 20 (1997), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Many plant species are sensitive to changes in the seasons, especially with regard to their reproductive behaviour. Sexual or vegetative reproductive structures are often only formed at times of the year when days are sufficiently long, or short. Plants perceive daylength in the leaves, but reproductive changes occur in shoot apices in response to the movement of signals throughout the plant. There is good evidence that phytochrome A is an essential component of the daylength-sensing mechanism in long-day plants, and preliminary evidence suggests a potential interaction between phytochrome C and daylength sensitivity in short-day plants. The sensitivity of reproductive processes to photoperiodic control is directly altered by photoreceptor action, particularly in the case of phytochrome B, which has a major influence on whether flowering or tuberization occurs under non-inductive conditions in both long- and short-day plants, but is not involved in daylength measurement. The signals which move from leaves to the sites of reproductive development are not known, but there is good evidence that gibberellins may be important and some preliminary indication that brassinosteroids might also be involved in photoperiodic signalling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1997.d01-110.x
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  • 3
    Electronic Resource
    Electronic Resource
    Evidence that photoperiodic, dark time measurement in Pharbitis nil involves a circadian rather than a semidian rhythm (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 18 (1995), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Experiments were carried out to determine whether a semidian (12 h) rhythm in flowering response operates in Pharbitis nil as the basis for photoperiodic time measurement. The effect of 5 min far-red light followed by 85 min dark (FRD) given 4, 8,14 and 22 h before the end of a 48 h photoperiod on night-break timing and critical night length was determined. When given 4 h before the end of a 48 h photoperiod, an interruption with FRD advanced the phase of the circadian rhythm in the night-break inhibition of flowering. In contrast, earlier interruptions of the photoperiod had no effect on the phase of the rhythm. The critical night length was modified by FRD given 4 h (shortened) or 8 h (lengthened) before the end of the photo-period; when given at other times FRD did not alter the critical night length. The results are discussed in relation to the basis for photoperiodic timekeeping, with particular reference to suggestions for the involvement of a semidian rhythm. A circadian model based on the concept of limit cycles is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1995.tb00201.x
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  • 4
    Electronic Resource
    Electronic Resource
    Ultraviolet-B effects on transcript levels for photosynthetic genes are not mediated through carbohydrate metabolism (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 20 (1997), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The relationship between UV-B-induced changes in gene expression and carbohydrate levels in pea seedlings has been investigated. The effect of supplementary UV-B radiation on the transcript abundance for two photosynthetic genes, photosynthesis, respiration and the levels of carbohydrates was determined in fully expanded leaves of 17-d-old pea seedlings under high (HL: 350 μmol m−2 s−1) and low (LL: 150 μmol m−2 s1) light. Supplementary UV-B caused down regulation of the photosynthetic genes in green leaves under LL and to a lesser extent under HL. In contrast to previous studies, UV-B radiation resulted in a decrease in glucose levels rather than an increase under LL. Sucrose and starch levels were not affected until longer exposure. Effects of UV-B on carbohydrate levels were, however, minimal under HL. The effects on transcript levels were most marked under LL and therefore could not be attributed to elevated carbohydrate levels. Comparison of UV-B effects on carbohydrates in source (leaf) and sink (green buds) organs indicated that changes in carbohydrates in response to UV-B are probably indirect and arise from effects of UV-B on photosynthesis in source organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1997.d01-39.x
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  • 5
    Electronic Resource
    Electronic Resource
    Seed dispersal and movement patterns in two species of Ceratogymna hornbills in a West African tropical lowland forest (2000)
    Springer
    Oecologia 125 (2000), S. 249-257 
    Details
    ISSN: 1432-1939
    Keywords: Seed dispersal Seed shadow Hornbills Telemetry Tropical frugivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. We studied two species of Ceratogymna hornbills, the black-casqued hornbill, C. atrata, and the white-thighed hornbill, C. cylindricus, in the tropical forests of Cameroon, to understand their movement patterns and evaluate their effectiveness as seed dispersers. To estimate hornbill contribution to a particular tree species' seed shadow we combined data from movements, determined by radio-tracking, with data from seed passage trials. For 13 individuals tracked over 12 months, home range varied between 925 and 4,472 ha, a much larger area than reported for other African avian frugivores. Seed passage times ranged from 51 to 765 min, with C. atrata showing longer passage times than C. cylindricus, and larger seeds having longer gut retention times than smaller seeds. Combining these data, we estimated that seed shadows were extensive for the eight tree species examined, with approximately 80% of seeds moved more than 500 m from the parent plant. Maximum estimated dispersal distances for larger seeds were 6,919 and 3,558 m for C. atrata and C. cylindricus, respectively. The extent of hornbill seed shadows suggests that their influence in determining forest structure will likely increase as other larger mammalian dispersers are exterminated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420000445
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  • 6
    Electronic Resource
    Electronic Resource
    Enhanced Evolvability in Immunoglobulin V Genes Under Somatic Hypermutation (1999)
    Springer
    Journal of molecular evolution 49 (1999), S. 23-26 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Genome evolution — Adaptability — Somatic hypermutation — Affinity maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Darwinian theory requires that mutations be produced in a nonanticipatory manner; it is nonetheless consistent to suggest that mutations that have repeatedly led to nonviable phenotypes would be introduced less frequently than others—if under appropriate genetic control. Immunoglobulins produced during infection acquire point mutations that are subsequently selected for improved binding to the eliciting antigen. We and others have speculated that an enhancement of mutability in the complementarity-determining regions (CDR; where mutations have a greater chance of being advantageous) and/or decrement of mutability in the framework regions (FR; where mutations are more likely to be lethal) may be accomplished by differential codon usage in concert with the known sequence specificity of the hypermutation mechanism. We have examined 115 nonproductively rearranged human Ig sequences. The mutation patterns in these unexpressed genes are unselected and therefore directly reflect inherent mutation biases. Using a χ2 test, we have shown that the number of mutations in the CDRs is significantly higher than the number of mutations found in the FRs, providing direct evidence for the hypothesis that mutations are preferentially targeted into the CDRs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006530
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  • 7
    Electronic Resource
    Electronic Resource
    Characterization of rice α-amylase isozymes expressed by Saccharomyces cerevisiae (1995)
    Springer
    Applied microbiology and biotechnology 43 (1995), S. 1050-1055 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Two rice α-amylase isozymes, AmylA and Amy3D, were produced by secretion from genetically engineered strains of Saccharomyces cerevisiae. They have distinct differences in enzymatic characteristics that can be related to the physiology of the germinating rice seed. The rice isozymes were purified with immunoaffinity chromatography. The pH optima for amy3D (pH optimum 5.5) and Amy1A (pH optimum 4.2) correlate with the pH of the endosperm tissue at the times in rice seedling development when these isozymes are produced. Amy3D showed 10–14 times higher reactivity to oligosaccharides than Amy1A. Amy1A, on the other hand, showed higher reactivity to soluble starch and starch granules than Amy3D. These results suggest that the isozyme Amy3D, which is expressed at an early stage of germination, produces sugars from soluble starch during the early stage of seed germination and that the isozyme Amy1A works to initiate hydrolysis of the starch granules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166924
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  • 8
    Electronic Resource
    Electronic Resource
    New ways of determining structural groups in brown coals and their bioconversion products by FT IR spectroscopy (2000)
    Springer
    Applied microbiology and biotechnology 54 (2000), S. 681-685 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract New methods of determining the structural groups —COOH and —CH2— have been developed. The investigation of carboxyl groups is possible both after derivatization with p-fluorophenacylbromide and by quantitative interpretation of the Fourier transform infrared (FT IR) spectra. There exists a linear relationship between the results of these two methods that is generally valid for the analysis of all brown coal components. The maximum extinction coefficient of the symmetric stretching vibration band of the CH2 groups has been determined using model substances. This allows quantification of this structural group directly from the FT IR spectrum. The results agree with the contents of methylene groups as determined by 13C-cross polarization–magic angle spinning–nuclear magnetic resonance (13C CPMAS NMR) spectroscopy. Using these methods, the COOH and CH2 groups contained in brown coals of the North Rhine region and in their bioconversion products have been quantified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530000419
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  • 9
    Electronic Resource
    Electronic Resource
    A new TNFA promoter allele identified in South American Blacks (1996)
    Springer
    Immunogenetics 44 (1996), S. 485-486 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002510050158
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  • 10
    Electronic Resource
    Electronic Resource
    Identification of the molecular basis for phosphorylase hypersensitivity in cultured diabetic cardiomyocytes (1995)
    Springer
    Molecular and cellular biochemistry 145 (1995), S. 131-139 
    Details
    ISSN: 1573-4919
    Keywords: glycogen phosphorylase ; alloxan-diabetes ; cardiomyocytes ; cGMP ; phosphodiesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The focus of this study was to identify the molecular basis for the hypersensitive response of glycogen phosphorylase activation to epinephrine stimulation in alloxan diabetic-derived cardiomyocytes. Cyclic AMP levels were found not to be significantly different between normal and diabetic-derived cells while cGMP concentrations were found consistently to be significantly lower in diabetic-derived cells than in normal cells. Treatment with cyclic GMP analogues did not affect phosphorylase activation by epinephrine in normal cardiomyocytes whereas, IBMX, a nonselective phosphodiesterase inhibitor, had a significant effect on basal and agonist-stimulated phosphorylase activity in both normal and diabetic-derived cardiomyocytes. Differences in the time course for the rate of decay of phosphorylasea from agonist-stimulated to basal levels were observed between normal and diabetic cells. After 3 h in primary culture, phosphorylasea activity returned to basal levels more quickly in normal than in diabetic-derived cells while after 24 h in culture, the time for phosphorylasea decay was not significantly different between normal and diabetic myocytes and was longer than the 3 h response. After 3 h in primary culture, no significant difference in phosphorylase kinase activity was observed between normal and diabetic-derived cells exposed to epinephrine whereas, after 24 h in culture, phosphorylase kinase activity was significantly decreased in diabetic cells under basal and agonist-stimulated conditions. These data collectively suggest that the hypersensitive response of glycogen phosphorylase to epinephrine stimulation in diabetic-derived cardiomyocytes is not due to a defect present at the level of phosphorylase kinase but may, in part, result from an alteration in cardiac phosphodiesterase activity resulting from diminished intracellular cyclic GMP concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00935485
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