Bacterial markers

Other applications dealt with the development of a luciferin ester substrate to measure the luciferase activity in living cells [141], the detection of toxic compounds such as sodium azide, fluoroacetic acid, and antibiotics [142], the development of a biosensor for the determination of bioavailable mercury [143], the use of eukaryotic luciferases as bacterial markers with different colors of luminescence [144], the determination of complement-mediated killing of bacteria [145], and the development of a bioassay for the determination of HIV type 1 virus and HIV-1 Tat protein activity, valuable also for analysis of HlV-inhibi-tory agents [146],... 

Large particles are responsible for elevated bacterial marker levels in school air upon occupation, I. Environ. Monit., 7,450 56. 

Not all monounsaturated fatty acids are biosynthesized as cis isomers with even numbers of C atoms. For example, trans-16 1(07 and trans-18 1(07 may be bacterial markers, whereas trans-16 1(013 is produced by photosynthetic bacteria and some phytoplankton but not cyanobacteria (Johns et al. 1979).The fatty acid distributions of cyanobacteria can be quite variable, with some exhibiting major 16 0 and 16 1(07, while others have abundant 18 lff)9.The odd-numbered acids 15 1 and 17 1 with C06 or (08 C=C bonds are bacterial markers, produced by the anaerobic biosynthetic route. Among the sulphate-reducing bacteria, 17 1(08 appears to be characteristic of Desulfohulhus (Taylor Parkes 1983). 

These branched acids can be source-specific and they are rarely unsaturated. They are formed by the incorporation of branched amino acids into the biosynthetic pathway, yielding iso and anteiso acids, as noted in Section 5.1.3. Iso and anteiso saturated fatty acids are found in fungi, molluscs and phytoplankton, but they are generally in higher levels in bacteria and are often observed in the C13—C17 range (Harwood Russell 1984).The C15 isomers (Fig. 5.1) are usually particularly abundant in bacteria and the ratio (iso + anteiso)/normal derived from C15 components can be used as an indication of relative bacterial contributions (Parkes Taylor 1983). Similarly, the (08 isomers of /. >- 5 1 and iso-17 1 are bacterial markers (Perry et al. 1979), and iso-17 1(07 is characteristically a major fatty acid in the sulphate-reducing bacteria Desulfovibrio desulfuricans (Taylor Parkes 1983). 

Fig. 3 a, b. Levels of biomarkers in plankton samples collected in Trinity Bay during the spring bloom of 1996 (After [50]). a Diatom markers and b dinoflageUate and bacterial markers. Significantly different (p < 0.05) from the same marker value in all other months... 

Several fatty acids, specifically 15 0, 17 0 and all branched fatty acids, are produced primarily by both aerobic and anaerobic bacteria [55-57] and the sum of those fatty acids has been used to estimate bacterial contributions [58-61]. A comparison of bacterial markers in plankton, sediment trap and sediment samples showed the lowest values, with little variation, in plankton samples (Fig. 3 b), and the greatest bacterial levels in sediments. The sediment traps, containing partially degraded material, had bacterial marker levels intermediate between the other two sample types, and levels of bacterial markers increased with increasing period of deployment. However, there are conflicting theories concerning the usefulness of these markers and, for that reason, bacterial markers should only be employed with caution. For instance, in a recent paper, Harvey and Macko [57] did not find a correlation between total fatty acids attributed to bacteria and bacterial carbon, and they suggest that bacterial fatty acids only be used as qualitative tools to estimate bacterial contributions. Wakeham [62] also points out that fatty acids of common oceanic bacteria may not be compositionally different from planktonic fatty acids so that bacterial... 

ImmunO lSS iy. Chemiluminescence compounds (eg, acridinium esters and sulfonamides, isoluminol), luciferases (eg, firefly, marine bacterial, Benilla and Varela luciferase), photoproteins (eg, aequorin, Benilld), and components of bioluminescence reactions have been tested as replacements for radioactive labels in both competitive and sandwich-type immunoassays. Acridinium ester labels are used extensively in routine clinical immunoassay analysis designed to detect a wide range of hormones, cancer markers, specific antibodies, specific proteins, and therapeutic dmgs. An acridinium ester label produces a flash of light when it reacts with an alkaline solution of hydrogen peroxide. The detection limit for the label is 0.5 amol. 

A. Fox and R. M. T. Rosario, Quantification of muramic acid, a marker for bacterial peptidoglycan in dust collected from hospital and home air-conditioning filters using gas-chromatography mass spectrometry. Indoor Air-Intemat. J. Air Quality Cl. 4 239 (1994). 

Pyuria The presence of white blood cells in the urine, a known marker of inflammatory response to bacterial infection. 

In bacterial cells, marker compounds are present at the part per hundred to part per thousand level. In environmental samples, which represent a complex mixture of components, such markers are often present at the part per ten thousand to part per hundred thousand level. In certain clinical samples, in some instances, these markers may be present as low as parts per... 

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