32,746 research outputs found

    Geographical distribution of resistance to spore killer in N. crassa and N. intermedia

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    Spore killer-2 (Sk-2K) is a rare meiotic drive factor found only in four (among about 2,500) collected cultures of N. intermedia, two from Borneo, and one each from Java and Papua New Guinea (Turner et al 1987 Fungal Genet. Newsl. 34:59-62). When strains carrying Sk-2K are crossed to other N. intermedia strains, each ascus contains four viable ascospores, which carry Sk-2K, and four aborted ascospores. In some populations of N. intermedia, one third to one half of the strains collected carry a gene, tightly linked or allelic to Sk-2K, which confers full or partial resistance to killing. In crosses between Sk-2K and a resistant (r(Sk-2)) strain, each ascus contains four viable Sk-2K progeny and four (sometimes fewer) viable r(Sk-2) progeny. N. intermedia is found around the world at all longitudes sampled, but resistance to Sk-2K is found only in approximately half the globe, roughly centered in the region where Sk-2K was found

    Dominance of the wild-type (sensitive) allele of cyh-1

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    Dominance of wild-type allele of cyh-

    Identification of the fragrant strain ATCC 46892 as Neurospora sitophila

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    Neurospora strains were among the various fungi isolated by Park et al. (J. Ferment. Technol. 60: 1-4, 1982) from naturally fermented cassava used to make the indigenous alcoholic beverage tiquira in Maranhao State, Brazil. One strain, deposited as ATCC 46892 and also available as FGSC 6673, was shown by Yoshizawa et al. (Agr. Biol. Chem. 52: 2129-2130, 1988) to have a pleasant fruity odor attributed to ethyl hexanoate. This strain has been the subject of numerous studies concerning production and application of the substance, including pilot studies of the possible use of 46892 in Japan for producing koji and saki (Yamauchi et al. Agric. Biol. Chem. 53: 821-825, 1989). I obtained the strain and crossed it to standard species testers of N. crassa and N. sitophila. The crosses to both A and a mating types of N. crassa were infertile, but the cross to an N. sitophila A tester, FGSC 5940, gave abundant asci with black viable ascospores, showing that 46892 is conspecific and that it does not carry the N. sitophila element Spore killer-1

    Substitution of paper for sucrose can reverse apparent male sterility in Neurospora

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    For many years we ascertained the species of newly collected Neurospora cultures by using them to fertilize standard species testers which had grown for five days on crossing medium with sucrose as the carbon source

    A putative fifth heterothallic species in Neurospora

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    Among Neurospora cultures sent to us by Daniel Le Pierres and Assienan Bernard from the vicinity of Abidjan, Ivory Coast, were two mixed cultures that made 8-spored asci when inoculated to synthetic crossing medium of Westergaard and Mitchell (1947) with filter paper as the only carbon source. Pure cultures of each mating type were obtained from conidial platings and were found to be sterile with all of the previously known species but highly fertile with some other Ivory Coast cultures (21 in addition to the first four). For all of these strains there has not been any mating reaction observed with N. sitophila or N. discreta, but it is barely possible to assign mating type from spot crosses on a lawn of N. crassa fl, and under optimum conditions there is sometimes formation of barren, unbeaked perithecia with N. intermedia. The new strains do not act as female parents on medium to which sucrose has been added

    Perceptions of the intergroup structure and anti-Asian prejudice amongst white Australians

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    Proof oSubjective intergroup beliefs and authoritarianism were assessed in a field study (N= 255) of White Australians’ anti-Asian stereotyping and prejudice. A social identity analysis of intergroup prejudice was adopted, such that perceptions of the intergroup structure (instability, permeability, legitimacy and higher ingroup status) were proposed as predictors of higher prejudice (blatant and covert) and less favorable stereotyping. Consistent with the social identity approach, both independent and interacting roles for sociostructural predictors of Anti-Asian bias were observed, even after demographic and personality variables were controlled. For example, perceived legitimacy was associated with higher prejudice when White Australians’ status position relative to Asian Australians was valued. Moreover, when participants evaluated Whites’ position as unstable and high status or legitimate, perceptions of permeable intergroup boundaries were associated with anti-Asian bias. The present findings demonstrate status protection responses in advantaged group members in a field setting, lending weight to the contention that perceptions of sociostructural threat interact to predict outgroup derogation. Implications for theories of intergroup relations are discussed

    Strains for studying Spore killer elements in four Neurospora species

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    This note gives a comprehensive list of stocks useful for working with Spore killer elements, including reference strains for use as testers, genetically marked derivatives, and strains sensitive and resistant to killing by Sk-1K, Sk-2K, and . Geographical site of origin is indicted for the various killer alleles. Many of the strains are newly deposited in FGSC. Some are listed also under other categories. Updated versions of the list will appear in future FGSC Stock Lists (Part IV, Special Purpose Stocks)

    Perturbative Theoretical Model of Electronic Transient Circular Dichroism Spectroscopy of Molecular Aggregates

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    A chiral analog of transient absorption spectroscopy, transient circular dichroism (TCD) spectroscopy is an emerging time-resolved method. Both spectroscopic methods can probe the electronic transitions of a sample, and TCD is additionally sensitive to the dynamic aspects of chirality, such as those induced by molecular excitons. Here, we develop a theoretical description of TCD for electronic multi-level models in which the pump pulse is linearly polarized and probe pulse is alternately left- and right-circularly polarized. We derive effective response functions analogous to those often used to describe other four-wave mixing methods and then simulate and analyze TCD spectra for three representative multi-level electronic model systems. We elaborate on the presence and detection of the spectral signatures of electronic coherences
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