Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Cell & Developmental Biology  (8)
  • Chemistry  (3)
  • Aphanocapsa 6308  (2)
  • Column liquid chromatography  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Arginine catabolism in Aphanocapsa 6308 (1978)
    Springer
    Archives of microbiology 118 (1978), S. 1-6 
    Details
    ISSN: 1432-072X
    Keywords: Arginine catabolism ; Arginine dihydrolase pathway ; Cyanobacteria ; Aphanocapsa 6308 ; Arginase ; Urease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The catabolic products of arginine metabolism were observed in Aphanocapsa 6308, a unicellular cyanobacterium, by thin layer chromatography of growth media, by limiting growth conditions, and by enzymatic analysis. Of the organic, nitrogenous compounds examined, only arginine supported growth in CO2-free media. The excretion of ornithine at a concentration level greater than citrulline suggested the existence in Aphanocapsa 6308 of the arginine dihydrolase pathway which produced ornithine, CO2, NH4, + adenosine 5′-triphosphate. Its existence was confirmed by enzymatic analysis. Although cells could not grow on urea as a sole carbon source a very active urease and subsequently an arginase were also demonstrated, indicating that Aphanocapsa can metabolize arginine via the arginase pathway. The level of enzymes for both pathways indicates a lack of genetic control. It is suggested that the arginase pathway provides only nitrogen for the cells whereas the arginine dihydrolase pathway provides not only nitrogen, but also CO2 and adenosine 5′-triphosphate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406066
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Variations in short term products of inorganic carbon fixation in exponential and stationary phase cultures of Aphanocapsa 6308 (1978)
    Springer
    Archives of microbiology 116 (1978), S. 231-234 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Aphanocapsa 6308 ; Inorganic carbon fixation ; C4 photosynthesis ; C3 photosynthesis ; Carbonate fixation ; Bicarbonate fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aphanocapsa 6308 metabolizes both NaHCO3 and Na2CO3. The short term incorporation (5-s) metabolic pattern and the patterns of incorporation of bicarbonate for exponential versus stationary phase cultures differ, however. Cells were equilibrated for 10 min in air and distilled water prior to injection of either NaH14CO3 at pH 8.0, or Na2 14CO3 at pH 11.0. Hot ethanol extracts were analyzed via paper chromatography and autoradiography for products of CO2 fixation. At 5 s, malate (51.5%) predominates slightly as a primary bicarbonate fixation product over 3-phosphoglycerate (40.3%); 3-phosphoglycerate is the primary product of carbonate fixation. At 60 s, the carbonate and bicarbonate labelling patterns are similar. Cells in stationary phase fix in 5 s a greater proportion of bicarbonate into malate (36% vs. 14% for 3-phosphoglycerate) than do cells in exponential growth. Likewise, 60 s incorporations show a large amount of bicarbonate fixed into aspartate (30.9%) in stationary phase cells over that of exponential phase (11.6%). These data suggest an operative C4 pathway for purposes not related to carbohydrate synthesis but rather as compensation for the incomplete tricarboxylic acid cycle in cyanobacteria. The enhancement of both aspartate fixation and CO2 fixation into citrulline in stationary phase correlates with an increase in cyanophycin granule production which requires both aspartate and arginine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417844
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The new generation of L. C. columns; A critical evaluation of their systems compatibility and performance (1985)
    Springer
    Chromatographia 20 (1985), S. 335-342 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; External variance determinations ; Column and system compatibility ; Microbore and fast LC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The demand for faster, more economic and convenient high-efficiency LC analyses has led to the development of microbore and fast columns. However, to utilize their benefits, the low column dispersions produced by these new technologies necessitate low external variances in the total system. This paper describes the determination of the external variance of microbore, fast and conventional LC systems by a column method. Compatibility with the relevant column technologies is evaluated by a method involving the comparison of the external and column dispersions. Direct comparison of chromatograms of an 8-component mixture, on a set of columns of various diameters and lengths, shows the relative speed, economy and sensitivity obtainable in practice. The problem of reduced sample loadability is considered and the practical solution of peak compression illustrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269058
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Folding in vitro of bovine pancreatic trypsin inhibitor in the presence of proteins of the endoplasmic reticulum (1992)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 14 (1992), S. 10-15 
    Details
    ISSN: 0887-3585
    Keywords: protein disulfide isomerase ; disulfide bonds ; protein folding ; chaperones ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The rate of folding and disulfide bond formation in reduced BPTI were measured in vitro in the presence and absence of total protein from the endoplasmic reticulum. The rates were increased substantially by the endoplasmic reticulum proteins, but only to the extent expected from the known content and activity of protein-disulfide-isomerase. No effects of added ATP or Ca2+ were observed, even though protein-disulfide-isomerase blinds Ca2+ tightly. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340140104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Evaluation of a complete HPLC solvent optimization system involving piece-wise quadratic modelling (1990)
    Springer
    Chromatographia 29 (1990), S. 79-89 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Solven optimization ; Piecewise quadratic modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Interpretive methods are accepted to give the best possible results for selectivity optimization in HPLC. However the methods are very complex, and most work so far has been detailed academic studies. This paper describes an evaluation of a complete integrated system incorporating peak labelling, modelling of retention behaviour and calculation of response surfaces, with particular emphasis on the retention modelling. The peak labelling section has been discussed previously. A piece-wise quadratic function is investigated for the modelling of retention times across an isoeluotropic plane to effect selectivity optimization in HPLC. This requires 10 data-points on the isoeluotropic plane. The predicted global optimum and local optima are evaluated by comparison of calculated and experimental retention data, for a nine component sample. Seven interstitial points, distributed across the whole plane between the data-points, are similarly evaluated for a related sample. The typical error (in retention time) is less than 2%, often 1%, and the maximum error is 4.2%. At the global optimum the error was found be less than 1.3% for all 9 peaks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261144
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Determination of cellular rate distributions in microbial cell populations: Feeding rates of ciliated protozoa (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 284-294 
    Details
    ISSN: 0006-3592
    Keywords: ingestion rate distribution ; population balance ; state properties ; rate properties ; flow cytometry ; particle uptake model ; Poisson process model ; Tetrahymena pyriformis ; suspension feeding ; filter feeding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel procedure is proposed for determining distributions of rate properties and correlations of rate with state properties of microbial cell populations. The procedure is novel in that it uses transient data, and thus, it does not require that the population be in balanced growth, although it requires that the population structure does not change during the short transient experiment. The procedure is applied to populations of the ciliated protozoan Tetrahymena to determine ingestion rate variability. The number of ingested microspheres per cell and the single-cell protein content - an indicator of cell size - were directly determined with dual-color flow cytometry. The proposed technique revealed the correlation pattern of the particle ingestion rate with cell size. In particular, ingestion rate was found to be positively correlated with cell size for the smaller feeding cells and to be uncorrelated with size for the larger cells. Using the fact that particle uptake from dilute particle suspensions is a Poisson random process, we determined that the coefficient of variation of the distribution of ingestion rates within the feeding population is about 50%. It was concluded that the dynamics of particle ingestion can be accurately described only if it is realized that particle ingestion rates are distributed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260420304
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Insertion of microscopic objects through plant cell walls using laser microsurgery (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 60 (1998), S. 348-355 
    Details
    ISSN: 0006-3592
    Keywords: Agrobacterium rhizogenes ; laser heating ; Ginkgo biloba ; optical scalpel ; optical tweezers ; plant cell culture ; plasmolysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A detailed protocol is presented for precisely inserting microscopic objects into the periplasmic region of plant callus cells using laser microsurgery. Ginkgo biloba and Agrobacterium rhizogenes were used as the model system for developing the optical tweezers and scalpel techniques using a single laser. We achieved better than 95% survival after plasmolyzing G. biloba cells, ablating a 2-4-μm hole through the cell wall using a pulsed UV laser beam, trapping and translating bacteria into the periplasmic region using a pulsed infrared laser beam, and then deplasmolyzing the cells. Insertion of bacteria is also described. A thermal model for temperature changes of trapped bacteria is included. Comparisons with other methods, such as a reverse-pressure gradient technique, are discussed and additional experiments on plants using laser microsurgery are suggested. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 348-355, 1998.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Effect of hypophysectomy and gonadotropin treatment on follicular development and ovulation in the hamster (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 139 (1974), S. 37-48 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In hamsters hypophysectomized on day 1 of the cycle (morning of ovulation) on days 1-28 post-hypophysectomy 99% of follicular development is limited to small and medium sized follicles with no more than five layers of granulosal cells. Since the largest preantral follicles on day 1 of the cycle have 10-12 layers of granulosal cells, it is evident that follicles become dependent on gonadotropins at an early stage of their maturation.The daily injection of 200 μg ovine follicle stimulating hormone (FSH) on days 8-11 post-hypophysectomy results in large antral follicles; when 10 μg ovine luteinizing hormone (LH) is then injected the animals ovulate 32 eggs. When 200 μg FSH on day 8 post-hypophysectomy is followed by 50 μg FSH on days 9-11, injecting LH results in the ovulation of nine eggs  -  comparable to the ovulation rate of intact hamsters. These experiments indicate that superovulation depends on sustained high levels of FSH whereas the ovulation of a normal number of eggs requires an initially high level of FSH and then much lower maintenance levels.When replacement therapy with 200 μg FSH for four days is started on the day of hypophysectomy (day 1) or day 2, follicles fail to develop past the six-seven granulosal layer stage. However, deferring the initial injection of FSH until day 3 results in antral follicles that are ovulated by LH (ovulation = 36 eggs). This suggests that functional corpora lutea inhibit the effects of FSH on follicular growth. Progesterone administered to hypophysectomized hamsters (days 8-11 post-hypophysectomy) increases the percentage of medium follicles at the expense of smaller stages. Progesterone injected daily along with FSH also prevents follicular development past the six-seven granulosal layer stage in 14 of 24 hypophysectomized animals.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001390103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Cell cycle regulation by environmental pH (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 517-525 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Purified populations of quiescent human tumour cells were isolated from plateau phase cultures of PMC-22 cells by centrifugal elutriation. Dilution into fresh medium resulted in these quiescent cells entering S phase exponentially with a t1/2 of 12 hr, after a 18-20-hr lag period during which cellular RNA content increased. Subsequent studies showed that recruitment of quiescent cells into the cell cycle could be regulated by extracellular pH. When exponentially growing PMC-22 cells were exposed to acidic extracellular pH levels, three growth patterns were observed: (1) Normal growth between pH 7.2 to pH 6.8; (2) A reduction in growth rate associated with accumulation of cells with a G1 DNA content between pH 6.7 and 6.4 (this was also shown to occur in a number of other tumour cell lines); (3) Non-cell-cycle-phase-specific arrest of growth at pH levels less than 6.3. Further studies with purified quiescent cell populations showed the possible existence of a pH-dependent restriction point in the G1 phase of these tumour cells. The implications of these observations to tumour biology are discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210310
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Activation of protein kinase C inhibits human keratinocyte migration (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 156 (1993), S. 487-496 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The involvement of protein kinase C (PKC) in epidermal growth factor (EGF)-induced human keratinocyte migration was studied with the phagokinetic assay. It was concluded that PKC activation does not mediate, but rather inhibits, EGF-induced keratinocyte migration. The following experimental observations support these conclusions: 1) The PKC inhibitor H-7 did not inhibit EGF-induced migration but instead led to a modest enhancement. 2) PKC activators such as phorbol-12-myristate-13-acetate (PMA), phorbol-12,13-dibutyrate (PDBu), and 1,2-dioctanoly-sn-glycerol inhibited migration, but biologically inactive 4α-PMA had no effect. 3) PMA did not inhibit keratinocyte attachment and spreading but blocked migration almost immediately after addition. 4) Migration of PKC-depleted cells, which were produced by prolonged treatment with PDBu, was enhanced similarly to normal cells by EGF. 5) PKC-depleted cells were not susceptible to the inhibitory effects of phorbol esters on migration. Additional experiments, in which cells were preactivated with EGF, suggested that PKC inhibits the EGF effect at a post-receptor level. The inhibitory effect of PKC on keratinocyte migration was not restricted to EGF-induced migration; PKC activation also inhibited keratinocyte migration induced by bovine pituitary extract, insulin, insulin-like growth factor-1, and keratinocyte growth factor. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041560308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...