Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1432-1890
    Keywords: Key words Extraradical hyphae ; Micronutrients ; Nutrient uptake ; Root colonization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sustainability of soil-plant systems requires, among other things, good development and function of mycorrhizal symbioses. The effects of P and micronutrient levels on development of an arbuscular mycorrhizal fungus (AMF) and uptake of Zn, Cu, Mn and Fe by maize (Zea mays L.) were studied. A pot experiment with maize either inoculated or not with Glomus intraradices was conducted in a sand:soil (3 :1) mix (pH 6.5) in a greenhouse. Our goal was to evaluate the contribution of mycorrhizae to uptake of Cu, Zn, Mn and Fe by maize as influenced by soil P and micronutrient levels. Two levels of P (10 and 40 mg kg−1 soil) and three levels of a micronutrient mixture: 0, 1X and 2X (1X contained, in mg kg−1 soil, 4.2 Fe, 1.2 Mn, 0.24 Zn, 0.06 Cu, 0.78 B and 0.036 Mo), were applied to pots. There were more extraradical hyphae at the low P level than at the high P level when no micronutrients were added to the soil. Root inoculation with mycorrhiza and application of micronutrients increased shoot biomass. Total Zn content in shoots was higher in mycorrhizal than non-mycorrhizal plants grown in soils with low P and low or no micronutrient addition. Total Cu content in shoots was increased by mycorrhizal colonization when no micronutrients were added. Mycorrhizal plants had lower Mn contents than non-mycorrhizal plants only at the highest soil micronutrient level. AMF increased total shoot Fe content when no micronutrients were added, but decreased shoot Fe when plants were grown at the high level of micronutrient addition. The effects of G. intraradices on Zn, Cu, Mn, and Fe uptake varied with micronutrient and P levels added to soil.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 116 (2002), S. 6755-6759 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a systematic study of the effect of size and shape on the spectral response of individual silver nanoparticles. An experimental method has been developed that begins with the detection and characterization of isolated nanoparticles in the optical far field. The plasmon resonance optical spectrum of many individual nanoparticles are then correlated to their size and shape using high-resolution transmission electron microscopy. We find that specific geometrical shapes give distinct spectral responses. In addition, inducing subtle changes in the particles' morphology by heating causes a shift in the individual particle spectrum and provides a simple means of tuning the spectral response to a desired optical wavelength. Improved colloidal preparation methods could potentially lead to homogeneous populations of identical particle shapes and colors. These multicolor colloids could be used as biological labels, surface enhanced Raman scattering substrates, or near field optical microscopy sources covering the full range of wavelengths in the visible spectrum. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Arylamine N-acetyltransferases (NATs; E.C 2.3.1.5) N-acetylate arylhydralazine and arylamine substrates using acetyl coenzyme A. Human NAT2 acetylates and inactivates the antituberculosis drug, isoniazid (INH), and is polymorphic. We previously demonstrated that there is a homologue of human NAT2 in Mycobacterium tuberculosis, whose product N-acetylates INH in vitro. We now demonstrate that the nat gene is expressed in M. tuberculosis and M. bovis Bacille Calmette-Guerin (BCG), using reverse transcription–polymerase chain reaction and Western blotting. The NAT protein is active in M. bovis BCG in vivo, as detected by the presence of N-acetyl INH in M. bovis BCG lysates grown in INH. Sequence analysis of the M. tuberculosis nat coding region reveals a single nucleotide polymorphism in 18% of a random cohort of M. tuberculosis clinical isolates, conferring a G to R change. The recombinant mutant protein appears less stable than the wild type, and has an apparent affinity for INH of 10-fold less than the wild type. Modelling the change in M. tuberculosis NAT shows that the G to R change is close to the active site, and supports the experimental findings. Minimum inhibitory concentration data suggest that this polymorphism in nat is linked to low-level changes in the INH susceptibility of M. tuberculosis clinical isolates.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 431 (2004), S. 49-52 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Not all noise in experimental measurements is unwelcome. Certain fundamental noise sources contain valuable information about the system itself—a notable example being the inherent voltage fluctuations (Johnson noise) that exist across any resistor, which allow the temperature to be ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 409 (2001), S. 303-303 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Inbreeding, which can lead to the loss of genetic variation or the accumulation of deleterious alleles, has been shown to reduce fitness in wild, zoo, laboratory and farmed animals. But it has been proposed that when combined with selection, inbreeding may purge deleterious alleles. Here ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd.
    Journal of neurochemistry 75 (2000), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract : 5-Aminolevulinic acid (5-ALA) is a precursor of porphyrins and heme that has been implicated in the neuropsychiatric symptoms associated with porphyrias. It is also being used clinically to delineate malignant gliomas. The blood-CSF barrier may be an important interface for 5-ALA transport between blood and brain as in vivo studies have indicated 5-ALA is taken up by the choroid plexuses whereas the normal blood-brain barrier appears to be relatively impermeable. This study examines the mechanisms of 5-[3H]ALA uptake into isolated rat lateral ventricle choroid plexuses. Results suggest that there are two uptake mechanisms. The first was a Na+-independent uptake system that was pH dependent (being stimulated at low pH). Uptake was inhibited by the dipeptide Gly-Gly and by cefadroxil, an α-amino-containing cephalosporin. These properties are the same as the proton-dependent peptide transporters PEPT1 and PEPT2, which have recently been shown to transport 5-ALA in frog oocyte expression experiments. Choroid plexus uptake was not inhibited by captopril, a PEPT1 inhibitor, suggesting PEPT2-mediated uptake. The presence of PEPT2 and absence of PEPT1 in the choroid plexus were confirmed by western blotting. The second potential mechanism was both Na+ and HCO3- dependent and appears to be an organic anion transporter, although it is possible that removal of Na+ and HCO3- may indirectly affect PEPT2 by affecting intracellular pH. The presence of PEPT2 and a putative Na+/HCO3--dependent organic anion transporter is important not only for an understanding of 5-ALA movement between blood and brain but also because these transporters may affect the distribution of a number of drugs between blood and CSF.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sociological inquiry 71 (2001), S. 0 
    ISSN: 1475-682X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Sociology
    Notes: Although social scientists have written much recently about environmentalism, feminism, and gender, insufficient systematic examination of their interrelations has been done. The lack of adequate research on links among these three concepts limits their usefulness for both grassroots mobilization efforts and general theory development. The present exploratory study surveys a college student sample (N = 393) clarifying the relationships between liberal environmentalism, gender, and feminism. Relationship between feminism and attitudes toward human use of the environment and between gender and environmental regulation are found suppressed by a relationship between feminism and environmentalism. Although tentative, these findings suggest new directions for the study of ecofeminism.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 27 (2000), S. 0 
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Amylin is a pancreatic peptide that has been shown to be able to induce a state of peripheral insulin resistance. Hyperamylinaemia, which occurs in type 2 diabetes, may be central to a number of metabolic abnormalities present in the diabetic state. Because lipoprotein metabolism is often disturbed in diabetes, we investigated whether amylin was a regulating factor of lipoprotein metabolism in rats; specifically, whether exogenous amylin influences production and clearance of triglyceride (TG)-rich lipoproteins.2. When amylin was given acutely to rats or by way of infusion, total plasma TG was significantly elevated. Acute doses of amylin decreased fractional clearance rates of TG-rich lipoproteins by 45%. Hydrolysis of lipoproteins by endothelial lipases was not decreased; rather, amylin appeared to reduce hepatic uptake of TG-rich lipoproteins, following conversion to the remnant form. Consistent with the kinetic data in vivo, cell culture studies found that amylin reduced the high-affinity uptake of remnant lipoproteins, probably by inhibiting low-density lipoprotein receptor expression.3. We have found that amylin can influence the kinetics of TG-rich lipoproteins in vivo and in vitro. Amylin can reduce chylomicron uptake, most probably by regulating lipoprotein receptors either directly, or via modulation of insulin activity. Increased levels of amylin in type 2 diabetes may contribute to the raised concentration of TG-rich remnant lipoproteins present in this disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science, Ltd
    Aquaculture research 32 (2001), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The high cost of cholesterol used in aquaculture diets for shrimp makes it important to precisely define their requirement for this essential nutrient in order to avoid excess supplementation of the diet. Two experiments were carried out to determine the cholesterol requirement of subadult (about 3 g) Penaeus monodon (Fabricius). The growth response and survival of shrimp were compared following feeding for up to 8 weeks with diets in which the cholesterol content varied between 0.7 and 8.5 g kg−1. Feed intake was quantified and the retention of ingested cholesterol determined by whole body analysis. The cholesterol requirement of subadult P. monodon was found to be about 75 mg kg−1 body weight d−1. The optimum dietary cholesterol content was approximately 1.7 g kg−1 (dry matter), which is appreciably lower than the current recommendation of 2.5–4 g kg−1. In most practical shrimp diets, the endogenous cholesterol in the ingredients provides more than 1.7 g kg−1 of cholesterol. Hence, our research suggests that it may be unnecessary to add expensive, supplementary cholesterol to commercial shrimp diets.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1527-3458
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...