Solid media, preparation

LB (+Amp) solid medium. Prepare LB as in the case for LB (+Km). Just before pouring into Petri dishes, add ampicillin at 50 pg/ml. Store the plates at 4°C. 

It is possible to also test semi-solid antibacterial preparations on the skin itself, as described for liquid disinfectants (section 3.5.1). A portion of the skin— the backs of the fingers between the joints is a useful spot— is treated with the test organism, the preparation is then applied and after a suitable interval the area is swabbed and the swab incubated in a suitable medium. Alternatively, the method employing pig skin, described in section 3.5.1, may well be adapted to the problem of testing semi-solid skin disinfectants. 

The hairy roots, which had various lengths from root tips of L = 5.0 X 10 3 m to 9.0 x 10 2 m, were prepared and placed on MS solid medium after their lateral roots were cut off. The dishes were incubated in a chamber at 5.0% C02 concentration and incident light intensities were kept at 11 W m-2 and 20 W m 2 on the level of the medium surface. 

Membranes prepared from cast pellets of silver halides have been used successfully in electrodes for the selective determination of chloride, bromide, and iodide ions. In addition, an electrode based on a polycrystalline Ag2S membrane is offered by one manufacturer for the determination of sulfide ion. In both types of membranes, silver ions are sufficiently mobile to conduct electricity through the solid medium. Mixtures of PbS, CdS, and CuS with Ag S provide membranes that are selective for Pb-, Cd-+, and Cu-", respectively. Silver ion must be present in these membranes to conduct electricity because divalent ions are immobile in crystals. The potential that develops across crystalline solid-state electrodes is de.scribed by a relationship similar to Equation 21-10. 

The seeds for solid-state fermentation are prepared either by submerged culture or solid-state culture. Bran is an excellent medium for solid seed preparation. After the spores have matured, the solid seeds are harvested and mixed with the pre-sterilized medium for solid-state fermentation. The ratio between solid seeds and medium is around 1 20-50. 

Herbicide resistant mutants are selected on a solid sterile selection medium prepared by autoclaving a minimal salts nutrient solution (21) with 0.7% agar. After cooling to 30C the herbicide Is added and the medium Is distributed to 9 cm petrl plates. Initially a range of herbicide concentrations should be tested to determine the lowest concentration of herbicide that kills germinating wild-type seedlings effectively. This concentration Is then used for the large-scale... 

Preparation 4r-l Candida strains may be cultivated in a nutritive medium containing assimilable carbon and nitrogen sources, essential mineral matter, trace elements and the like under aerobic conditions, and the medium may be constructed in a conventional manner. After the cultivation, insoluble substances are removed by filtration or centrifuging to prepare a concentrated solution of liquid enzyme, and a culture solution may be subsequently evaporated or concentrated by reverse osmosis. The concentrated solution may be precipitated in a solvent capable of being mixed with salts or water, for example ethanol, or may be dried in a conventional spray manner to prepare a solid enzyme preparation. 

In general, benzoylation of aromatic amines finds less application than acetylation in preparative work, but the process is often employed for the identification and characterisation of aromatic amines (and also of hydroxy compounds). Benzoyl chloride (Section IV, 185) is the reagent commonly used. This reagent is so slowly hydrolysed by water that benzoylation can be carried out in an aqueous medium. In the Schotten-Baumann method of benzoylation the amino compound or its salt is dissolved or suspended in a slight excess of 8-15 per cent, sodium hydroxide solution, a small excess (about 10-15 per cent, more than the theoretical quantity) of benzoyl chloride is then added and the mixture vigorously shaken in a stoppered vessel (or else the mixture is stirred mechanically). Benzoylation proceeds smoothly and the sparingly soluble benzoyl derivative usually separates as a solid. The sodium hydroxide hydrolyses the excess of benzoyl chloride, yielding sodium benzoate and sodium chloride, which remain in solution ... 

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. 

Transparent solid samples can be analyzed directly by placing them in the IR beam. Most solid samples, however, are opaque and must be dispersed in a more transparent medium before recording a traditional transmission spectrum. If a suitable solvent is available, then the solid can be analyzed by preparing a solution and analyzing as described earlier. When a suitable solvent is not available, solid samples may be analyzed by preparing a mull of the finely powdered sample with a suitable oil. Alternatively, the powdered sample can be mixed with KBr and pressed into an optically transparent pellet. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Processes have been developed in North America to pilot scale growing the bacterium Cellulomonas or the fungus Trichoderma on pre-treated milled cellulosic material in conventional fermentors, ie in a liquid medium. However, preparation costs are considerably higher than with solid-substrate fermentations. 

The hydrochloride may be isolated in a 35% yield as a stable and easy to handle white solid. The free amine T8[(CH2)3NH2]8 can be prepared in a quantitative yield by the reaction of T8[(CH2)3NH3C1]8 in methanol with a basic Amberlite IRA-400 exchange resin (Table 24, entry 3). Alternatively, if the initial solvolysis of H2N(CH2)2Si(OEt)3 is carried out in a basic medium the free amine is reported to be formed directly in excellent yield (Table 24, entry 4). In this case, decomposition of the resulting amine was not reported (see below). 

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