Gene amplification occurs frequently in tumour tissues yet is,in general, non-inheritable. To study the molecular mechanismsconferring this restraint, we created transgenic mice carryinga human butyrylcholinesterase (BCHE) coding sequence, previouslyfound to be amplified in a father and son. Blot hybridizationof tail DNA samples revealed somatic transgene amplificationswith variable restriction patterns and intensities, suggestingthe occurrence of independent amplification events, in 31% (11/35)of mice from the FII generation but in only 3.5% (2/58) of theFII and FIV generations. In contrast, >10-fold amplificationsof the BCHE transgene and the endogenous acetylcholinesteraseand c-raf genes appeared in both testis and epididymis DNA from>80% of FIII mice. Drastic, selective reductions in testisBCHEmRNA but not in actin mRNA were detected by the PCR amplificationof testis cDNA from the transgenic mice, and apparently resultedin the limited transmission of amplified genes. The testicularamplification of the BCHE transgene may potentially representa general phenomenon with clinical implications in human infertility. 相似文献
Summary. Monoclonal antibodies Ds-1 and Ds-2 specifically labelling dog sperm acrosome were prepared by immunization of mice with acetic acid extracts of dog spermatozoa. Electron microscopy and indirect immunofluorescence localized the site of Ds-1 and Ds-2 proteins inside the acrosomal vesicle. Ds-1 antibody detected 55, 76, 115, 120 and 190kDa proteins under non-reducing conditions, and 73 kDa and 54 kDa proteins after reduction (p73/Ds-1 and p54/Ds-1). 92 kDa and 40 kDa proteins recognized by Ds-2 (p92/Ds-2 and p40/Ds-2) migrated at > 200 kDa in the absence of reducing agent. In vivo , p73/Ds-1 and p54/Ds-1 are therefore likely to be present both in free and complexed form, while all of p92/Ds-2 and p40/Ds-2 form disulfide-bonded complexes. Decrease in the rate of acrosomes stained with Ds-1 and Ds-2 was correlated with the progress of capacitation resulting in the increased rate of spontaneous acrosome reactions, as suggested by a dramatic effect of A23187. Monoclonal antibody to boar acrosin (ACR-2) recognized dog sperm acrosin homologue. A higher rate of ACR-2-negative spermatozoa was observed after capacitation and A23187 treatment compared to Ds-1 and Ds-2, indicating that proteins recognized by Ds-1 and Ds-2 are localized in a specific compartment of acrosome, distinct from acrosin and possibly representing fraction of acrosomal matrix. 相似文献
1. 1. Acute effects of alcohol and diazepam on reaction time (RT) and event-related potential (ERP) measures were examined in 108 healthy male volunteers.
2. 2. The subjects engaged in a simple RT task at two levels of stimulus intensity during baseline and treatment sessions.
3. 3. Lower stimulus intensity produced increased RTs, increased ERP peak latencies, and suppression of peak amplitudes.
4. 4. Moderate and high doses of alcohol, and high doses of diazepam produced increased RTs. Alcohol suppressed P100 and N100 amplitudes, while diazepam suppressed P100 amplitudes only. P100 amplitudes were correlated to RTs under baseline and treatment conditions.
5. 5. These results were taken as evidence for impaired stimulus detection during alcohol and diazepam intoxication, with both drugs influencing sensory-perceptual processes and alcohol alone influencing the degree of attentiveness.
Author Keywords: alcohol; diazepam; event-related potentials; simple reaction time 相似文献