ABSTRACT
The integrase of the temperate bacteriophage mv4 catalyzes site-specific recombination between the phage attP site and the attB site of the host during lysogenization of Lactobaccillus delbrueckii subsp. bulgaricus. The mv4 integrase also functions in a wide variety of gram-positive bacteria and in Escherichia coli. In this report, in vitro and in vivo recombination assays were developed and the integrase was purified in order to study in greater detail the mv4 attP x attB recombination event. In a cell-free extract of E. coli at 42 degrees C, the mv4 integrase promotes efficient in vitro recombination between a supercoiled attP-containing plasmid and a linear attB fragment. The integrase, which was purified to apparent homogeneity, showed no absolute requirement for accessory factors, unlike the majority of the lambda Int family of recombinases. Deletion derivatives of the attP site were constructed and tested for recombination with the attB site in vitro. A 234-bp DNA fragment containing five scattered putative mv4 Int-binding sites was sufficient for function of the attP site. In contrast to the right arm of attP, most of the left arm could be deleted without drastically reducing the recombination efficiency. In vivo in E. coli, mv4 Int catalyzed recombination in trains between attP and attB sites present on two separate plasmids. This property was used to confirm in vivo the results of the deletion analysis of the attP site performed in vitro.
Subject(s)
Bacteriophages/genetics , Lactobacillus/virology , Recombination, Genetic , Virus Integration , Base Sequence , Escherichia coli , Histidine , Integrases/isolation & purification , Integrases/metabolism , Lactobacillus/genetics , Molecular Sequence DataABSTRACT
PIP: A new copper IUD, the OMGA, has been recently tested in France. The IUD is made of a resilient, plastic material containing pure copper in powder form. The device comes in 4 sizes, containing an amount of copper ranging from 37 mg to 120 mg; the period of device use can very well be over 5 years. The main feature of the new device is that (contrary to what happens in other IUDs in which the quantity of copper released decreases after the 1st year of use) the amount of copper released remains stable all the time. Between 1979-1981, 197 OMGA IUDs were inserted by the authors for a total of 2420 cycles; age of acceptors was mostly over 35, and most were multiparous. Insertion of the device was very easy. There were 4 pregnancies, or a failure rate of 1.98%; there were 24 expulsions, or 11.9%, and 7 removals, or 3.47%; reasons for removal were metrorrhagia menorrhagia, pain, and spotting in most cases. Duration and quantity of menstrual flow was similar to that for other types of IUDs. There were no cases of infection or of perforation. The limited number of observations conducted until now does not permit definitive conclusions on the effectiveness of the OMGA.^ieng
Subject(s)
Contraception , Copper , Equipment and Supplies , Evaluation Studies as Topic , Intrauterine Devices , Research , Age Factors , Chemical Phenomena , Chemistry , Contraception Behavior , Diagnosis , Family Planning Services , Inorganic Chemicals , Menorrhagia , Metals , Metrorrhagia , Pain , Parity , Patient Acceptance of Health CareABSTRACT
Instruments are at the basis of microsurgery. An operating microscope is the main element and the most important and expensive thing to buy. Yet it is possible to begin with a simple microscope as the ZEISS OMPI 1, or its copy by BAG. Five or six intruments are necessary except irrigation set up, clamps, bipolar coagulation. Suture material will be selected for each times. Microsurgery demands an important training before applying it in the operating room. A good operating position will also be required in order to perform efficiently.
