Culture media bacteria

J. S. Rocha, M. J. Barbosa, Wijffels (2001) Hydrogen production by photosynthetic bacteria culture media, yields and efficiencies, In Biohydrogen II. J. Miyake, T Matsunaga, A. San Pietro eds. Pergamon, Amsterdam 3-32... 

HYDROGEN PRODUCTION BY PHOTOSYNTHETIC BACTERIA CULTURE MEDIA, YIELDS AND EFFICIENCIES... 

Hydrogen Production by Photosynthetic Bacteria Culture Media, Yields and Efficiencies... 

Iodine speciation has been successfully carried out using capillary electrophoresis coupled to inductively coupled plasma mass spectrometry. The status of iodine species (such as thyroxine, triiodothyronine or iodide) in serum or urine can give information about the malfunction of the thyroid gland and can explain other metabolic abnormalities. Chromium speciation is not normally required in biological samples because the body converts all of the Cr + to Cr + and so the measurement of total chromium in blood and urine is referred to when in fact Cr + has been determined. Chromium speciation has been carried out in bacteria culture medium, which has used to convert Cr + to Cr ". ... 

In the 1950s, a group of coryneform bacteria which accumulate a large amount of L-glutamic acid in the culture medium were isolated (21). The use of mutant derivatives of these bacteria offered a new fermentation process for the production of many other kinds of amino acids (22). The amino acids which are produced by this method are mostiy of the T.-form, and the desired amino acid is singly accumulated. Therefore, it is very easy to isolate it from the culture broth. Rapid development of fermentative production and en2ymatic production have contributed to the lower costs of many protein amino acids and to their availabiUty in many fields as economical raw materials. 

The autoinducer is a low molecular weight compound that is easily leached from the cells into the culture medium. By the propagation of bacterial cells, the concentration of the autoinducer in the medium increases. When the concentration reaches a certain threshold, the biosynthesis of bioluminescence system begins, and the bacteria become luminescent. The process is also called quorum sensing (Fuqua et al., 1994). 

The conditions for production of TTX and STX by bacteria are unknown. The low levels of TTX and STX observed in laboratory cultures may indicate that the host environment has not been duplicated. Likely, the composition of culture medium and other physicochemical parameters for TTX and STX production have not yet been defined in vitro. Conversely, bacteria may actually produce only small amounts of TTX and STX in vivo that accumulate in host tissues over long time intervals. 

Method. Figure 3 shows the equipment used by us for loading a culture medium with radon and decay products. Air was circulated in a closed system, driven by a membran pump (MP). The system consisted of a Ra-226 solution (Ra), a security bubble flask with water (H20), a membran bacteria filter (MF) and a second bubble flask containing 100 ml RPMI 1640 culture medium (CM). This medium contains 100 IE/ml penicilin and streptomycin and 0.75% L-glutamin. Foetal calf serum, an essential part of blood cultures, must not be added, else the airstream would develop foam. Furthermore we added a small amount of Pb(N03)2 and Bi(N03)2, about 10 ng of each, as "carriers" for the radon decay products to avoid a "wall effect". 

The assay is usually conducted in a plate form, with revertant colonies stained and counted. However, to increase the assay s sensitivity for weaker mutagens, the fluctuation assay can be conducted. In this modification, bacteria treated with the suspect mutagen are grown in suspension culture rather than plated out. Increased turbidity of the culture medium over time is used to detect the presence of revertants. 

The individual components of the cDNA library may be obtained by grouping individual bacteria on a culture medium so that they reproduce to form identical clones. This enables a large quantity of specific cDNAs to be produced in a pure form. The cDNA within these plasmid-containing bacteria can then be removed, and the precise nucleotide sequence determined by standard automated analytical procedures. 

The medication is a sterile water extract from autotrophic bacteria Ferrooxidans spp. culture medium. It is a reddish liquid with acidic reaction (pH 3.0) and astringent action. The preparation does not cause irritation of tissues and is intended for external use. However, at present the possibility of its oral administration is being studied. 

Nucleotide Biosynthesis in Amino Acid Auxotrophic Bacteria Normal E. coli cells can synthesize all 20 common amino acids, but some mutants, called amino acid aux-otrophs, are unable to synthesize a specific amino acid and require its addition to the culture medium for optimal growth. Besides their role in protein synthesis, some amino acids are also precursors for other nitrogenous cell products. Consider the three amino acid auxotrophs that are unable to synthesize glycine, glutamine, and aspartate, respectively. For each mutant, what nitrogenous products other than proteins would the cell fail to synthesize ... 

Til. Mode of Action of Sulfa Drugs Some bacteria require p-aminobenzoate in the culture medium for normal growth, and their growth is severely inhibited by the addition of sulfanilamide, one of the earliest sulfa drugs. Moreover, in the presence of this drug, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR see Fig. 22-33) accumulates in the culture medium. These effects are reversed by addition of excess p-aminobenzoate. 

An example of enzyme induction is the growth of the bacteria Escherichia eoli in a suitable culture medium. If no beta-galactoside is added to the medium, the bacteria Form scarcely any of the enzyme that hydrolyzes that sugar. The addition of the sugar to the medium increases the production of the enzyme by the cell by as much as 10.000 times. On the other hand, the same bacteria will produce the enzyme tryptophan synthase only if tryptophan is absent from the culture medium. These observations are useful, not oniy... 

The host bacteria used for production of recombinant proteins are usually E. coli, or Bacillus subtilis they may express proteins at 1 % to over 50% of the cellular protein, depending on such variables as the source, promoter structure, and vector type. Generally the proteins are expressed intracellularly, but leader sequences for excretion may be included. In the latter case, the protein is generally excreted into the periplasmic space, which limits the amount that can be produced. Excretion from grampositive species such as B. subtilis sends the product into the culture medium, with little feedback limitation on total expression level. 

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