The effect of cupreous and plumbic salts on the physiology of phototrophic microorganisms isolated from stone historical buildings in simulation experiments

The influence of cupreous and plumbic salts on the degree of chalk samples fouling by algobacterial colonization isolated from the limestone surface of historical buildings of Arkhangelskoye National Museum and the physiological state of enrichment cultures of micro-algae have been studied. With this in view, photosynthetic activeness of microalgae was determined by the amperometric method for oxygen separation and pulse amplitude modulation for delayed chlorophyll luminescence.     

Microorganisms in Heat Supply Systems and Internal Corrosion of Steel Pipelines

In laboratory experiments with batch cultures of thermophilic microorganisms isolated from urban heat supply systems, the growth of sulfate-reducing, iron-oxidizing, and iron-reducing bacteria was found to accelerate the corrosion rate of the steel-3 plates used in pipelines. In the absence of bacteria and dissolved oxygen, minimal corrosion was determined. The aforementioned microorganisms, as well as sulfur-oxidizing bacteria, were found to be widespread in water and corrosion deposits in low-alloy steel pipelines (both delivery and return) of the Moscow heat networks, as well as in the corrosion deposits on the steel-3 plates in a testing unit supplied with the network water. The microorganisms were found in samples with a water pH ranging from 8.1 to 9.6 and a temperature lower than 90°C. Magnetite, lepidocrocite, goethite, and X-ray amorphous ferric oxide were the corrosion products identified on the steel-3 plates, as well as siderite, aragonite, and S⁰. The accumulation of corrosion deposits and variation in the total and local corrosion of the steel plates in a testing unit were considered in terms of the influence of microbial processes.     

Physiological features of rapeseed plants expressing the gene for an antimicrobial peptide cecropin P1

Transgenic rapeseed (Brassica napus L.) plants carrying an artificial gene for the antimicrobial peptide cecropin P1 (cecP1) were obtained and characterized. The agrobacterial transformation was done by vacuum infiltration of seeds with agrobacterium GV3101(pMP90RK) containing a binary vector pGA482::cecP1. The cec1 gene expression was analyzed by Western blotting and confirmed by antimicrobial activity measurements of plant extracts. The obtained plants showed the resistance to the bacterial and fungal pathogens Erwinia carotovora and Fusarium sporotrichioides. The photosynthetic activities of control and transgenic plants under biotic stress conditions of E. carotovora infection were comparatively studied. The higher tolerance of the cecP1 plants to the oxidative stress caused by paraquat was shown. The results obtained point to the possibility of incorporation of the cecropin P1 gene into the integral stress protection system of plants.     

Effect of the lipid component of the medium on lipase biosynthesis by fungi

The lipolytic activity of the fungi Aspergillus and Rhizopus was studied on a medium with soybean flour. The lipolytic activity of the Aspergillus fungi was low or absent whereas many of the cultures belonging to the Rhizopus genus possessed the lipolytic activity. The effect of soybean flour components on lipase biosynthesis was studied with Geotrichum asteroides and Rhizopus cohnii AUCMF-597. The lipid component was shown to be necessary for lipase biosynthesis by G. asteroides and to stimulate lipase synthesis by Rh. cohnii AUCMF-597. Oleic acid is presumed to activate lipase biosynthesis by G. asteroides.