Plasmids controlling the resistance to several antibiotics in C. perfringens type A, strain 659]

A strain of C. perfringens type A, isolated from a patient, was found to be resistant to four antibiotics: tetracycline (Tet), chloramphénicol (Chl), erythromycin (Ero) and clindamycin (Cli). Clones resistant to only two drugs (Tet-Chl or Ero-Cli), or sensitive to all drugs were found in cultures of the wild-type strain treated by acridine dyes or ethidium bromide. DNA analysis by equilibrium centrifugation confirmed that the original strain contains two resistance plasmids, one called Rip 401 (Tet-Chl) and the other Rip 402 (Ero-Cli), which represent respectively 1.8 +/- 0.2% and 2.3 +/- 0.2% of the total amount of DNA in this strain of Cl. perfrigens.     

Myricetin glycosides inLysimachia punctata

Resumen Miricetina-3-ramnósido y miricetina-3- arabinósido se identificaron enL. punctata (Primulacea). Otros dos glicósidos parecen ser miricetina-3-glucósido y miricetina-3-soforósido o 3-gentiobiósido.     

Neurohumoral regulation of motility and blood flow in the colon

Zusammenfassung Indiz, dass Plasma-Kinin sowohl in den Regulationsmechanismus der Kolon-Motilität als auch der Blutströmung eingreift.     

Stimulation of the synthesis and non-competitive inhibition of alkaline phosphatase by theophylline in normal hamster fibroblasts and absence of response in transformed fibroblasts]

Theophylline increases the synthesis of alkaline phosphatase in normal Hamster fibroblasts (activity X6 after 24 hours with theophylline 10-3 M). The enzymatic activity of these cells is inhibited by theophylline in vitro (80% inhibition in the presence of theophylline 10-3 M). The inhibition seems to be non competitive, since the apparent Km of the enzyme is not modified. This stimulator and inhibitor effect of theophylline is absent in Hamster fibroblasts transformed by SV 40 virus.     

Rapid freezing of biologic tissue. Measurement of temperature and rate of freezing by thin-layer thermocouple]

An apparatus for rapid freezing of biological tissues by contact with a copper block cooled by liquid helium has been devised to reduce the contamination of copper block surface. It prevents the precooling of the specimen while going through the layers of cold helium gas surrounding the copper block and reduces the quantity of helium necessary for freezing. It also enables one to obtain easily reproducible results from freezing by immersion in liquid coolants. Freezing rates are measured directly, related to the specimen thickness, by a thin film thermocouple; its low thermal inertia gives speed measurements of the order of 100,000 degrees C/s.