ISSN:0167-7063    

DOI:10.3109/01677068309107067

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

A selection for autosomal circadian rhythm variants inDrosophila melanogasterresulted in the isolation of 3 new mutants, all of which display an abnormal synchronization of daily rhythms to entraining environmental cycles. In populations of phase-angle-2(psi-2)and phase-angle-3(psi-3)mutants, daily peaks of adult emergence are hours earlier than normal when the strains are entrained to cycles of either light and dark or high and low temperature. Like an early-emerging strain previously isolated inDrosophila pseudoobscura thepsistrains have slightly lengthened periods for the circadian rhythm in adult emergence. In addition,psi-2brings about an abnormal synchronization of locomotor activity to light-dark cycles and lengthens periods for the activity rhythm. The emergence of adults in a third mutant strain designatedgatis poorly synchronized becoming aperiodic in conditions of continuous darkness and constant temperature.

ISSN:0167-7063    

DOI:10.3109/01677068309107068

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Recombinational dissection of theShrK0120strain ofDrosophila melanogasterdemonstrated that its extremely prolonged neuromuscular transmission, a defect qualitatively different from otherShalleles, results from a synergistic interaction with a second site mutation. This new mutation caused spontaneous repetitive firing in motor axons and increased transmitter release. Complementation tests showed that it is allelic toeag.Combining eithereagallele with variousShalleles reproduced the same extreme defect observed in the originalShrK0120strain. Thus, from their effects on neuromuscular transmission no qualitative difference amongShalleles is apparent whileSh, eag, andeag Shdouble mutant individuals can be uniquely distinguished. Pharmacological experiments indicated thatShaffects a membrane component sensitive to the potassium channel blockers 4-AP and TEA whileeagaffects a component sensitive to TEA but not 4-AP. We suggest thateagandShpreferentially disrupt different potassium currents explaining their synergistic interaction.

ISSN:0167-7063    

DOI:10.3109/01677068309107069

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Neural tube closure was studied in embryos obtained from matings of male mice heterozygous for a reciprocal chromosome translocation (T(2;4)1 Sn) with normal female (CFLP) mice. When litters were examined on the 9th to 12th days of gestation, there was a high incidence of resorption, developmental delay and neural tube closure defects in these embryos. SEM observations indicated that the neural tube closure defects ranged in severity from a side-to-side flattening of the midbrain to extensive anomalies in which the entire cephalic neural tube had failed to close.In addition to cephalic defects, a number of embryos exhibited open defects or abnormal subectodermal blebbing in the future lumbosacral region. In spinal regions, even in areas in which the neural tube had previously closed, it often was irregular and folded. These observations are discussed in relation to studies of gene-related defects of neural tube closure.

ISSN:0167-7063    

DOI:10.3109/01677068309107070

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Trembler-J,TrJ, is a peripheral hypomyelinating murine mutant. In intercrosses(TrJ/+ xTrJ/ +) there are severely affected (behaviorally and pathologically), mildly affected, and normal offspring, while back-crosses(TrJ/+ x + /+) produce only mildly affected and normal offspring. We used the closely linked marker vestigial tail,vt, to test whether severely affected offspring of intercrosses(TrJvt/+ + xTrJvt/+ +) wereTrJ/ TrJ.In 5/6 intercrosses all severely affected animals were short-tailed and vice versa, while all mildly affected animals had long tails and vice versa. It is highly probable that the severely affected, mildly affected, and normal classes of intercross offspring were ofTrJ/ TrJ, TrJ/+, and + / + genotypes, respectively.

ISSN:0167-7063    

DOI:10.3109/01677068309107071

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Pallid mutant mice with no otoconia in their gravity receptors were behaviorally tested and their vestibular nuclei measured to determine if this developmental sensory deprivation had any detrimental effect on central vestibular structure and function. This absence of otoconia was correlated with disorientation in water and absence of air righting reflexes. The inferior and superior vestibular nuclei were smaller than normal, but neurons within regions that receive direct gravity receptor input were smaller only unilaterally in medial vestibular nucleus. It was tentatively concluded that the sensory deprivation resulting from reduced gravity receptor input was responsible for the behavioral and central morophological abnormalities.

ISSN:0167-7063    

DOI:10.3109/01677068309107072

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

The base sequence complexity of total and polysomal poly(A +)RNA from rat cerebellum was measured during postnatal development by RNA-DNA hybridization. At saturation, total and polysomal poly(A +)RNA from neonate cerebellum hybridized to 12.7% and 5.0% of the single-copy genomic DNA, respectively. Assuming asymmetric transcription, the sequence complexity of these RNA populations is sufficient to code for 100,000 different gene transcripts. The percentage of single-copy DNA expressed as total and polysomal poly(A +)RNA declined during postnatal development, reaching adult values of 10.0% and 4.1%, respectively. These results indicate that cerebellar maturation is accompanied by significant reductions in the diversity of genetic information expressed in the tissue.

ISSN:0167-7063    

DOI:10.3109/01677068309107073

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Dominantly inherited spinocerebellar ataxia (OPCA 1) poses a particular problem for genetic counseling due to late age of onset. Liability for disease using observed age of onset can be combined with HLA linkage data to provide revised estimates of risk for affection. Where data is informative, certain combinations may yield estimates which improve so rapidly with age that postponement of childbearing may become a strong consideration as an option.

ISSN:0167-7063    

DOI:10.3109/01677068309107074

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Actin and tropomyosin in muscle samples from normal humans, from human fetuses between 12 and 17 gestational weeks, and from patients with a variety of neuromuscular disorders were studied with two-dimensional electrophoresis using isoelectric focusing with either a broad pH range (8.6-4.5) or a narrow pH range (5.9-3.8) for the first dimension and either SDS or SDS-urea for the second dimension. With the broad pH range, two brothers with Duchenne muscular dystrophy were noted to have a less acidic variant of aL-tropomyosin in biceps muscle which was not found in biceps muscle from other patients or controls. Studies of 8 additional biopsy specimens from patients with Duchenne muscular dystrophy and comparison with both fetal and normal human muscle using the narrow pH range revealed multiple forms of actin and tropomyosin which varied from individual t o individual. This heterogeneity appeared to be unrelated to the dystrophic state but also obscured the ability to detect a change in actin or tropomyosin which could be related to dystrophy.

ISSN:0167-7063    

DOI:10.3109/01677068309107075

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

Two aL and twoβtubulin subunits are synthesized in vitro by polyadenylated mRNAs isolated from fetal and adult human cortex. The relative levels of the mRNAs encoding the different subunits change dramatically during development. In the fetus, the mRNA forβ1tubulin is present at higher levels than that of theβ2electrophoretic variant. There are relatively high levels of the mRNAs encoding both a subunits. In the adult, the levels of the mRNAs encoding both the a subunits and theβ1subunit are decreased relative to those of the mRNAs encoding theβ2subunit. These results suggest that fetal and adult cortical cells have very different requirements for the different tubulin electrophoretic variants.

ISSN:0167-7063    

DOI:10.3109/01677068309107076

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor