M3 medium

Cells are cultured in M3 medium with 5% FBS at 27°C. There is no CO2 requirement for buffering the medium. 

For a detailed discussion of culture media, see Cherbas and Cherbas (1998). The situation for casual cell users has been simplified by the fact that most common media for Drosophila cell culture are now commercially available. For example, most lines can be grown in M3 medium supplemented with 10% fetal calf serum, and M3 is available commercially both as liquid and as dry powder. For our larger-scale needs, we continue to manufacture M3 medium using the recipe in Schneider and Blumenthal (1978). Antibiotics are not in general necessary. For serum and its preparation by heat treatment and for more information about needles, see Cherbas and Cherbas (1998). 

Modified medium lacking leucine, yeast extract, and serum. M3 medium lacking leucine and methionine is available in powdered form from Sigma. 

Studies show that the production of 1kg dry biomass requires 2.0 kg sugar, 0.7 kg oxygen, 0.1 kg ammonia, with the liberation of 12,300 k Joules heat. A typical continuous fermentation operates at a dilution rate (D) = 0.2 h 1, with sugar concentration of 3% (w/v) in the incoming medium. With a fermentor of 50 m3 capacity and 90% utilisation of carbohydrate [ie 0.3% (w/v) sugar in the outgoing medium] what would be ... 

Studying the steady motion of a single medium-size bubble rising in a liquid medium under the influence of gravity, Levich (L3, L4) solved the continuity equation simultaneously with the equations of motion by introducing the concept of a boundary layer for the case of a bubble. This boundary layer accounts for the zero, or extremely low, shear stress at the interface. Despite some errors in deriving the equations, his result was later confirmed with minor improvements (A4, M3, M10). 

Type of Filter BOD5 Loading (kg/m3 d) Hydraulic Loading (m3/m2 d) Depth (m) BOD Removal (%) Medium... 

A slurry of CaC03 in water at 25°C containing 20% solids by weight is to be filtered in a plate-and-frame filter. The slurry and filter medium are tested in a constant pressure lab filter that has an area of 0.0439 m2, at a pressure drop of 338 kPa. It is found that 10 3m3 of filtrate is collected after 9.5 s, and 5 x 10 3 m3 is collected after 107.3 s. The plate and frame filter has 20 frames, with 0.873 m2 of filter medium per frame, and operates at a constant flow rate of 0.00462 m3 of slurry per second. The filter is operated until the pressure drop... 

Cell cultures. Cell cultures, covered with a 10 mm layer of medium in petri-dishes, were exposed for one week to an atmospheric radon concentration of 260 kBq/m3 ("high level exposure ), resp. 37 kBq/m ( low level exposure ). The Rn-decay product concentration was 6 WL, resp. 0,9 WL (RaA 61, resp. 8,6 kBq/m, RaB 25, resp. 3,6 kBq/m 3, RaC 13, resp. 1,8 kBq/m ). After an exposure for one... 

Two other phases are included for interest. Suspended matter in water is often an important medium when compared in sorbing capacity to that of water. It is treated as having 20% organic carbon and being present at a volume fraction in the water of 5 x 10 6, i.e., it is about 5 to 10 mg/L. The volume is thus 106 m3. Fish is also included at an entirely arbitrary volume fraction of 10 s and are assumed to contain 5% lipid, equivalent in sorbing capacity to octanol. The volume is thus 2 x 10s m3. These two phases are small in volume and rarely contain an appreciable fraction of the chemical present, but it is in these phases that the highest concentration of chemical often exists. 

For advection, it is necessary to select flow rates. This is conveniently done in the form of advective residence times, t in hour (h) thus the advection rate G is V/t m3/h for each medium. For air, a residence time of 100 hours is used (approximately 4 days), which is probably too long for the geographic area considered, but shorter residence times tend to cause air advective loss to be a dominant mechanism. For water, a figure of 1000 hours (42 days) is used, reflecting a mixture of rivers and lakes. For sediment burial (which is treated as an advective loss), a time of 50,000 hours or 5.7 years is used. Only for very persistent, hydrophobic chemicals is this process important. No advective loss from soil is included. The D value for loss by advection DAi is G,Z and the rates are DAif mol/h. 

The Level I calculation suggests that if 100,000 kg (100 tonnes) of benzene are introduced into the 100,000 km2 environment, 99% will partition into air at a concentration of 9.9 x 10-7 g/m3 or about 1 pg/rn3. The water will contain nearly 1% at a low concentration of 4 pg/rn3 or equivalently 4 ng/L. Soils would contain 5 x 10-6 pg/g and sediments about 9.7 x 10 6 pg/g. These values would normally be undetectable as a result of the very low tendency of benzene to sorb to organic matter in these media. The fugacity is calculated to be 3.14 x 10-5 Pa. The dimensionless soil-water and sediment-water partition coefficients or ratios of Z values are 2.6 and 5.3 as a result of a Koc of about 55 and a few percent organic carbon in these media. There is little evidence of bioconcentration with a very low fish concentration of 3.0 x FT5 pg/g. The pie chart in Figure 1.7.6 clearly shows that air is the primary medium of accumulation. 

The bioconversion process of Acid Orange 7 will be hereby analyzed. This is an incremental study with respect to that due to Lodato et al. [41], based on the operation of an airlift reactor with cells of Pseudomonas sp. 0X1 immobilized on natural pumice (density = 1,000 kg/m3 particle size = 800-1,000 pm). Details regarding the strain, medium, culture growth and main diagnostics of the liquid phase are reported by Lodato et al. [41]. Elemental analysis of dry biomass was obtained by a C/H/N 600 LECO analyzer. 

Free cyanide criteria currently proposed for natural resource protection include <3 pg/L medium for aquatic life, and <100 mg/kg diet for birds and livestock. For human health protection, free cyanide values are <10 pg/L drinking water, <50 mg/kg diet, and <5 mg/m3 air. 

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