PubMed · 5831350
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
1965-02-12. Birtheez.. https://pubmed.ncbi.nlm.nih.gov/5831350/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The hydrolytic activity of lambda exonuclease, a highly processive enzyme, is inhibited by high pressure. When assayed at 67 MPa, the activity is 87% of the atmospheric rate; increasing the pressure to 336 MPa causes a greater than 99% inhibition of the enzyme activity. Decreasing the pressure from 336 MPa to 67 MPa at 20 degrees C reverses the inhibition. The use of hydrostatic pressure to control the activity of lambda exonuclease has potential practical application in DNA sample preparation, analysis, and sequencing.
The formation of plaques by lambda phage in Escherichia coli was prevented by elevated hydrostatic pressure; phage plaques were not detected at 30 MPa. Furthermore, using promoter fragments derived from the malB operon, we showed that gene expression initiated from both promoters (malK-lamB and malEFG) was repressed by elevated hydrostatic pressure. Our findings suggest that high pressure affects gene expression directed by the malB regulatory interval, and this may cause a decrease in the quantities of lambda receptor protein, LamB.
OBJECTIVE: Our purpose was to determine whether there is a relationship between changes in atmospheric pressure and spontaneous onset of labor in term pregnancy. STUDY DESIGN: All women admitted to Medical Center of Central Massachusetts-Memorial Hospital with spontaneous onset of labor at term and who were delivered on the service during a 12-month period represent the cohort for this study. Each maternal chart was abstracted to ensure that each member of the cohort met the inclusion criteria. Hourly recordings of atmospheric pressure made at the Worcester Station of the National Weather Service, Department of Commerce, were used as the meteorologic data points of interest. Least-squares regression was used to determine an equation that expresses the probability of the onset of labor in this cohort as a function of gestational age, which was used to calculate expected numbers for the statistical analyses. Two relationships were studied: (1) the ratio of the observed to the expected number of onsets of labor and (2) the initiation of labor and atmospheric pressure changes in the preceding 3 hours. RESULTS: Three-hour periods of falling atmospheric pressure were less often followed by initiation of labor than were the periods with other types of pressure sequences. No association was observed between the onset of labor and days of low mean pressure. CONCLUSION: Although there was an observed statistically significant association between falling barometric pressure and onset of labor, the magnitude of the difference is not of clinical significance.