4,112 research outputs found

    Sequence and analysis of genomic sequences upstream of mei-3.

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    he Neurospora crassa mei-3 mutation causes sensitivity to various DNA damaging agents (Newmeyer and Galeazzi 1977 Genetics 85:461-487). We have recently cloned and mapped a genomic fragment capable of transforming mei-3 spheroplasts to wild type (Cheng et al. 1993 Mut. Res. 294:223-234). These experiments predicted the putative coding sequence of mei-3 or at least the region encompassing the mei-3 mutation. It was determined by homology that Mei-3 belongs to the RecA-like group of proteins (Bishop et al. 1992 Cell 69:439-456) which are intimately involved in the recombination process and had been previously identified only in prokaryotes. Since the identification of RecA-like proteins in Saccharomyces (Shinohara et al. 1992 Cell 69:457-470) and in Neurospora, our hypothesis that this important group of proteins may be highly conserved in other eukaryotes has been substantiated with the cloning of several Rec-A like proteins from mouse, chicken, lily, and human (Shinohara et al. 1993 Nat. Genet. 4:239-243). Using these data there is evidence that additional homology, upstream of our putative start site, to these other proteins exists (an additional 67% over 39 amino acids between Mei-3 and mouse Rad51: Figure 1). However, this region of homology lacks a start site or obvious splice sites. This might suggest the presence of an unidentified upstream start sequence and another exon without obvious splice sequences. In an attempt to address this possibility, we sequenced both strands of the previously unpublished genomic sequence, from -2519 to -271 bp upstream of the putative 5\u27 end of mei-3

    The wing coupling apparatus and the morphometric analysis of honeybee populations

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    Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used

    Parasitic Cape bees in the northern regions of South Africa: source of the founder population

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    Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%

    Apis florea in Jordan: source of the founder population

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    A recent isolated population of Apis florea has been reported from Aqaba in Jordan at the Red Sea, consisting of numerous colonies within a still limited range which apparently is expanding. This region is about 1500 km apart from its next occurrences in Sudan where it had been introduced and first detected in 1985 and about 2000 km apart from its next natural occurrences in Iran and Oman. These bees apparently have been imported by human transport, most likely by ship. This new location thus represents a major jump in the progression of the species still to fill a wide area of possible locations offering adequate living conditions. Here we attempt to track the possible origin of this new population by morphometric methods. This analysis indicated closest relation to A. florea from Oman, thus being the most likely source of this population

    The use of a nonradioactive probe in RFLP analysis of Neurospora crassa DNA

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    Our laboratory is investigating the use of nonradioactive alternatives for the synthesis of DNA probes used in hybridization experiments

    Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies

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    We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata

    A scientific note on the natural merger of two honeybee colonies (Apis mellifera capensis)

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    Natural mergers of honeybee colonies are commonplace in tropical Africa (Hepburn and Radloff, 1998), but their consequences on organizational structure are unknown. Here we determine the spatial distribution and division of labor of workers (Apis mellifera capensis Esch.) following a merger of two colonies. Two unrelated colonies (each ~3000 bees) were placed in threeframe observation hives. When workers emerged from the sealed brood of each colony, they were individually labeled and reintroduced into their respective mother hives. They are referred to as cohorts Aand B, each comprising 300 workers of the same age. The behaviors and positions of all labeled workers and queens were recorded twice daily for 24 days (Kolmes, 1989; Pirk et al., 2000). On day 14 colony B was dequeened, left its nest and merged with colony A on day 15

    A Study of Work Practices in Tasmanian Government Schools: Final report to the Australian Education Union – Tasmanian Branch

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    The Australian Council for Educational Research (ACER) conducted an online survey of members on behalf of the Tasmanian Branch of the Australian Education Union (AEU). The survey, which was open to teachers, school leaders (principals and assistant principals) and education support staff working in Tasmanian government schools and offices, was available to the majority of members of the Union in August 2017, and remained open for four weeks during Term 3. The survey was based on one conducted for the Victorian branch of the AEU in 2016. The survey of the work of union members in Tasmanian government schools focussed on the hours of work by school staff, staff perceptions of their work, and the relationship between work practices and the quality of teaching. More than 3000 teachers, school leaders and education support staff completed the survey, a response rate of 60%
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