5,810 research outputs found

    An effective procedure for the preparation of Neurospora conidiophores for scanning electron microscopy.

    Get PDF
    An effective procedure for the preparation of Neurospora conidiophores for scanning electron microscopy

    Tergitol-induced colonial growth without inhibition of conidiation

    Get PDF
    The cloning of genes from Neurospora crassa usually involves transformation of a mutant with genomic library DNA and the subsequent identification of transformants showing wild-type phenotype (Vollmer and Yanofsky 1986. Proc. Natl. Acad. Sci. 83:4869- 4873). This can be problematic in the case of morphological mutants, because the sorbose- containing medium that is typically used to promote colonial growth of the transformants tends to interfere with conidiation, and sometimes inhibits aerial hyphal growth altogether. The medium described below uses the nonionic detergent tergitol (Tatum et al. 1949. Science 109:509-511) to induce colonial vegetative growth without affecting aerial hyphal growth or morphology

    Collectors of Rhodiola species on the Sichuan-Tibetan and Sichuan-Shaanxi borders

    Get PDF
    Medicinal Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook.f. & Thomson) H.Ohba, have been widely used as traditional herbal medicines with numerous claims for their therapeutic effects. Faced with resource depletion, environment destruction and higher demand, R. rosea and R. crenulata are becoming endangered, making them economically even more valuable, but also increasing the risk of adulteration and low quality - and raising awareness for the role of often unlicensed collectors and middlemen. Although R. rosea is the most well known in Europe, R. crenulata is the recognised species in China. On the border of Sichuan and Tibet, members of the Yi minority collect R. crenulata in order to sell it to the “traditional” Chinese medicine market. Collection of this medicinal herb represents about one third of the annual income for the Yi. Three times a year they climb up to 5,000 metres in search of the plants. As it is stripped out, the Yi have to travel to more and more inhospitable places to ensure its supply. At Taibai mountain along the border of Sichuan and Shaanxi, the same medicinal plant, hongjingtian in Chinese, is growing in the wild, too. Yet, in a socioeconomic context, collectors do not have a particular ethnic background such as Yi, Tibetan or Han collectors. Here, the collectors are various unlicensed providers-cum-prescribers 'caoyi'. (The term does not mean herb-physician, as one might assume from terms such as caoyao (herbals). It means unofficial or not following the scholarly standard.) Using neither an ethnic identity nor the general botanical terms in Latin, they claim Daoism and terroir of their mountain as a sign of good quality ‘Taibai hongjingtian’. There appears to be no strategy in place to protect the species across all those socioeconomic, ethnic and provincial boundaries, and without some intervention it is likely that R. crenulata will eventually become so rare that it can no longer be collected in the current quantities. This will have consequences both for the livelihoods of the Yi and of various Caoyi, and also for the conservation of R. Crenulata and it’s sustainability

    A Survey of Southern Agricultural Broadcast Programming

    Get PDF
    In light of deregulation and the changing requirements for broadcasters, we wondered if we might see a decrease in the use of agricultural services

    Profiling expression changes caused by a segmental aneuploid in maize

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>While changes in chromosome number that result in aneuploidy are associated with phenotypic consequences such as Down syndrome and cancer, the molecular causes of specific phenotypes and genome-wide expression changes that occur in aneuploids are still being elucidated.</p> <p>Results</p> <p>We employed a segmental aneuploid condition in maize to study phenotypic and gene expression changes associated with aneuploidy. Maize plants that are trisomic for 90% of the short arm of chromosome 5 and monosomic for a small distal portion of the short arm of chromosome 6 exhibited a phenotypic syndrome that includes reduced stature, tassel morphology changes and the presence of knots on the leaves. The knotted-like homeobox gene <it>knox10</it>, which is located on the short arm of chromosome 5, was shown to be ectopically expressed in developing leaves of the aneuploid plants. Expression profiling revealed that ~40% of the expressed genes in the trisomic region exhibited the expected 1.5 fold increased transcript levels while the remaining 60% of genes did not show altered expression even with increased gene dosage.</p> <p>Conclusion</p> <p>We found that the majority of genes with altered expression levels were located within the chromosomal regions affected by the segmental aneuploidy and exhibits dosage-dependent expression changes. A small number of genes exhibit higher levels of expression change not predicted by the dosage, or display altered expression even though they are not located in the aneuploid regions.</p

    Quantum affine Cartan matrices, Poincare series of binary polyhedral groups, and reflection representations

    Full text link
    We first review some invariant theoretic results about the finite subgroups of SU(2) in a quick algebraic way by using the McKay correspondence and quantum affine Cartan matrices. By the way it turns out that some parameters (a,b,h;p,q,r) that one usually associates with such a group and hence with a simply-laced Coxeter-Dynkin diagram have a meaningful definition for the non-simply-laced diagrams, too, and as a byproduct we extend Saito's formula for the determinant of the Cartan matrix to all cases. Returning to invariant theory we show that for each irreducible representation i of a binary tetrahedral, octahedral, or icosahedral group one can find a homomorphism into a finite complex reflection group whose defining reflection representation restricts to i.Comment: 19 page

    Black holes admitting a Freudenthal dual

    Full text link
    The quantised charges x of four dimensional stringy black holes may be assigned to elements of an integral Freudenthal triple system whose automorphism group is the corresponding U-duality and whose U-invariant quartic norm Delta(x) determines the lowest order entropy. Here we introduce a Freudenthal duality x -> \tilde{x}, for which \tilde{\tilde{x}}=-x. Although distinct from U-duality it nevertheless leaves Delta(x) invariant. However, the requirement that \tilde{x} be integer restricts us to the subset of black holes for which Delta(x) is necessarily a perfect square. The issue of higher-order corrections remains open as some, but not all, of the discrete U-duality invariants are Freudenthal invariant. Similarly, the quantised charges A of five dimensional black holes and strings may be assigned to elements of an integral Jordan algebra, whose cubic norm N(A) determines the lowest order entropy. We introduce an analogous Jordan dual A*, with N(A) necessarily a perfect cube, for which A**=A and which leaves N(A) invariant. The two dualities are related by a 4D/5D lift.Comment: 32 pages revtex, 10 tables; minor corrections, references adde
    corecore