Pour plate procedure

Review pour plate procedure in Appendix C. (Sec C.3.I) Transfer yeast suspension to center of Petri plate and pour agar (at 44°G/ 111°F) over top. With a figure-8 motion, disperse suspension and agar. 

Fig. 2. Double diffusion, or simple diffusion, in a cell with parallel walls. The hatched area represents the intermediate part, cut in a sheet of plastic or of rubber, and placed between two glass plates held together with clamps. The first layer, usually of antiserum (AS) with agar, is poured as shown by arrow 1. When this layer has solidified, the second layer, made of pure gel (AG) when double diffusion is involved, is poured as shown by arrow 2. When the latter layer has solidified, the cell is rotated onto its side BC, and the layers of antigen solutions with agar (SI, S2) are successively poured as shown by the arrows 3 and 4, each layer having to be solid before the next layer is poured. The procedure is the same for simple diffusion, except that there is no layer AG.

If 30 is accepted as the lowest reliable number to count and a pour plate method uses a 1.0-ml sample, it follows that the procedures described above are unsuitable for any sample that is expected to contain <30 CFU ml-1, e.g. water samples where the count may be 1 CFU ml-1 or less. Here, membrane filter methods are used in which a large, known volume of sample is passed through the membrane which is placed, without inversion, on the agar surface. Nutrients then diffuse up through the membrane and allow the retained cells to grow into colonies on it just as they would on the agar itself. 

Compared with the pour plate described above, this procedure utilizes previously sterilized bent glass rods (spreaders or hockey sticks) to distribute a defined volume of sample evenly over the surface of the solidified agar medium. Compared with the pour-plate method, thermal shock is not a problem. However, complete transfer and separation of individual cells to yield separate countable colonies may be a concern. Also, excess moisture present on the agar s surface may result in unexpected colony spread... 

Procedure. Pour the developing solvent into the chromatographic tank to a depth of about 0.5 cm and replace the lid. Take a prepared plate and carefully spot 5 pL of each indicator on the origin line (see Section 8.6, under Sample application) using a micropipette. Allow to dry, slide the plate into the tank and develop the chromatogram by the ascending solvent for about 1 h. Remove the plate, mark the solvent front and dry the plate in an oven at 60 °C for about 15 min. Evaluate the R value for each of the indicators using the equation... 

Poly (2,4-d if luoro-1,5, pheny lene t r ime 11 i t ic amide-imide) was prepared by a two-step procedure 12 At the first step, the polyamic acid was prepared by reacting 2,4-difluoro-1,5-phenylene diamine with trimellitic anhydride acid chloride (with the mole ratio of one to one) in anhydrous N,N-dimethylacetaraide at room temperature under nitrogen. After reaction, the polymer was poured into water and precipitated. After filtration, the white solid was washed with distilled water and dried in a vacuum oven. The poly(amide-imide) was obtained from heating the polyamic acid at 220°C for 3 hours. The polyamic acid was dissolved in N,N-dimethyl acetamide or N,N-dimethyl forraamide, cast on glass plates, and the solvent evaporated in a vacuum oven to form a polyamic acid film before heating at 220°C. 

Procedure Prepare the chromatogrphic tank by lining the walls with sheets of filter paper pour the mobile-phase into the tank, saturating the filter paper in the process, to a depth of 5 to 10 mm, close the tank and allow it to stand at 20° to 25 °C for 1 hour for equilibration of the mobile-phase in the chromatank. Apply separately to the TLC plate 5 (il of each of two solutions (1) and (2) of apomorphine hydrochloride and (3) of morphine in the form of circular spots about 2 to 6 mm in diameter, and 15 to 20 mm from one end of the plate and not nearer than 10 mm to the sides the two spots must be at least 10 mm apart. Mark the sides of the plate 15 cm from the line of application. Allow the solvent to evaporate and place in the chromatank,... 

The general procedure for the electrochemical preparation of (10) is as follows. A solution of (9) (3 mmol) in wet acetonitrile (40 ml, 5 vol.% of H20) containing sodium perchlorate (0.25 m) was placed in an undivided electrolysis cell equipped with a platinum plate anode and a platinum plate cathode. The system was subjected to a constant current electrolysis (300 mA current density, 20mAcnr2) at ambient temperature. After 4 faradays per mole of (9) had been consumed, the electrolysed solution was poured into water (50 ml) and extracted with dichloromethane (3 X 30 ml). The organic layer was dried with magnesium sulfate and concentrated under reduced pressure. The residue was chromatographed on silica gel to afford (10) in an excellent yield. 

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