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Two genes of Aspergillus nidulans are known to function in UV mutagenesis, but have been assigned to different epistasis groups: uvsC, which is also required for meiosis and mitotic recombination, and uvsI, which may have no other function. To clarify their role in error-prone repair and to investigate their interaction, uvsI and uvsC single and uvsI;uvsC double mutant strains were further tested for mutagen sensitivities and characterized for effects on mutation. Spontaneous and induced frequencies were compared in forward and reverse mutation assays. All results confirmed that uvsI and uvsC are members of different epistasis groups, and demonstrated that these uvs mutants have very different defects in UV mutagenesis. The uvsI strains showed wild-type frequencies in all forward mutation tests, but greatly reduced spontaneous and UV-induced reversion of some, but not other, point mutations. In contrast, uvsC had similar effects in all assay systems: namely pronounced mutator effects and greatly reduced UV mutagenesis. Interestingly, the uvsI;uvsC double mutant strains differed from both single mutants; they clearly showed synergism for all types of reversion tested: none were ever obtained spontaneously, nor after induction by UV or EMS (ethylmethane sulfonate). Based on these results, we conclude that uvsI is active in a mutation-specific, specialized error-prone repair process in Aspergillus. In contrast, uvsC, which is now known to show sequence homology to recA, has a basic function in mutagenic UV repair in addition to recombinational repair, similar to recA of Escherichia coli. 相似文献
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Noncirrhotic portal fibrosis is a common cause of portal hypertension in India. We report the development of noncompressive myelopathy after a lienorenal shunt in a patient with noncirrhotic portal fibrosis. 相似文献
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DA Brown SK Effgen RJ Palisano 《Canadian Metallurgical Quarterly》1998,78(9):934-47; discussion 948-50
BACKGROUND AND PURPOSE: Do individuals with severely limited physical and cognitive abilities improve their gross motor abilities when given physical therapy intervention, and does improvement transfer to nontreatment settings? SUBJECTS: The subjects were 24 individuals (10 female, 14 male), aged 3 to 30 years (X = 20.1, SD = 8.1), who were nonambulatory and had limited adaptive behavior. METHODS: Change in gross motor ability during 18 weeks of twice-weekly therapy was measured using goal attainment scaling (GAS). Three gross motor goals were developed for each subject based on individual or caregiver needs, with one goal randomly selected as a control. Physical impairments were treated, and behavioral management principles, low-level communication approaches, high-repetition practice of goals, and a progressive reduction of both physical assistance and multisensory cues were used. An independent rater scored goal level from randomly ordered videotapes recorded during therapy and in recess and home settings. RESULTS: Mean GAS T scores were higher for treatment goals (X = 45.6, SD = 10.5) compared with control goals (X = 34.6, SD = 11.8). When the expected goal level (50) was met during therapy, mean GAS T scores in recess settings ( X = 35.9, SD = 11.5) and home settings (X = 42.2, SD = 12.2) were lower. At the conclusion of therapy, there were no differences in goal levels between treatment and control goals in both the recess and home settings. CONCLUSION AND DISCUSSION: The subjects demonstrated improvement of gross motor abilities practiced during therapy. Level of ability during therapy, however, did not consistently transfer to the recess of home settings. [Brown DA, Effgen SK, Palisano RJ. Performance following ability-focused physical therapy intervention in individuals with severely limited physical and cognitive abilities. 相似文献
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