Beggiatoa spp. - Molecular qualitative PCR detection and identification by sequencing

Information 02/15/10.

Beggiatoa spp. are bacteria that live in environments rich in sulfur. These bacteria use hydrogen sulfide (SH2: hydrogen sulphide) as a power source, and to oxidize, leading to intracellular globular sulfur deposits (2H2S + O2 ---> 2S + 2H2O). Under anaerobic conditions, sulfur (S °) may be an alternative electron acceptor and reduced to hydrogen sulfide (H2S). This was the first description of litotrofia (microbial life using inorganic compounds as energy source).

These oxidizer sulfur bacteria are found in marine and freshwater environments where there are high concentrations of hydrogen sulfide, reaching the interface between the sulfur and oxygen. These environments include: cold seeps, sulphurous fumes, polluted wastewater, lake sediments and marismeños near hydrothermal deep holes. In these places, they appear whitish forming layers, biofilms or bands associated with aerobic anaerobic-interface., Its presence generally in wastewater contaminated places, motivates consideration of kind of indicator bacteria pollution. They are found in all oceans, from areas near the coast, deep - sea and around hydrothermal holes. In areas with sulfur and oxygen mixed form diel vertical migration. Inside layer Beggiatoa mats usually occupies a narrow band (0.6 mm thick), which varies the movement of water. This bacterium, and other filamentous bacteria, can cause problems in treatment plants wastewater (bulking), industrial waste lagoons, preparing wood pulp grinding mills cereal grains, causing blockage. They may also detoxify hydrogen sulfide soil. The presence of Beggiatoa sediments prevents diffuse hydrogen sulfide in the water, since the biological sulphide oxidation is much faster than their chemical oxidation.

They are colorless, white or yellow bacteria, which appear as rounded or cylindrical filamentous, long and wide, forming aggregates that can be observed on surfaces to the naked eye. When globular contain sulfur deposits confer whitish or yellowish. When forming filaments, these are long filaments with a cell diameter can be 12 to 160 to 200 microns, depending on the species, so prokaryotes are larger. They have a central area, where vacuole - like nitrates accumulates (up to 160 nmol / l), to be used as an electron acceptor in anaerobic conditions sulphide oxidation. The filaments are surrounded by a biofilm and move under its own power ( "gliding").

Since the metabolically are varied, as there litótrofas species (-autótrofas- metabolism at the expense of inorganic chemical compounds) (quimiolitoautotrofia), using the sulfide and other sulfur compounds as energy source, strict organótrofas species ( -heterotróficas- metabolism at the expense of organic chemicals), using organic compounds as energy source. In litótrofas, the sulfur in the oxidation of hydrogen sulphide (or hydrogen sulphide) becomes sulfate to provide energy by fixing carbon dioxide (CO2) as the carbon source for the synthesis of biomass and using intracellular stores of nitrate as electron acceptors, which results in the reduced ammonium (NH4). By this, Beggiatoa spp. has a great effect on the aquatic nitrogen cycle, when using nitrates (NO3-) in anaerobiosis as an alternate electron acceptor instead of oxygen. The organic compounds used organótrofas become carbon dioxide in the presence of limited oxygen concentrations, this being the final electron acceptor. The organic compounds used in addition to providing energy, are the source of molecules for the synthesis of biomass. The oxygen concentration should be low, because if there was a high concentration could not survive lacking catalase to remove generated oxidizing compounds. The absence of catalase is offset by its ability to oxidize hydrogen sulfide, oxygen using peroxides. When there is no oxygen, they can reduce the hydrogen sulfide accumulated sulfur.

The requirement for sulfur and low oxygen concentration, Beggiatoa limited to places where there is a discontinuity of oxygen, such as interfaces between oxygenation and anaerobiosis (anoxia).

Tests in IVAMI

• Detection of the presence of Beggiatoa spp. by PCR amplification.

• Identification of the species of Beggiatoa spp. PCR amplification followed by sequencing of the amplicon obtained.

sample required

• Sediment or microbial mat, preferably obtained from the white layer located above the sediment, or water if, at the interface between layers of water. Indicative volume 10 mL.

Delivery of results

Beggiatoa spp. by molecular methods: between 48 and 96 hours as it has that sequence or not, for species identification.

Cost of Test