The cells of Metallogenium are spherical, 0.5-1.5 microns in diameter, and have no rigid cell walls. The bacteria attach to surfaces. They either germinate directly or repeatedly bud to form a rounded "matrix". Germination of these substrates results in the formation of one to several flexible filaments with tapered ends, occasionally bifurcating. In fixed and stained specimens, these filaments are 0.02-0.25 μm in diameter and can form a beaded appearance. When grown in culture conditions with manganese, the cells exhibited a high degree of light reflectivity. Microcolonies or definitive colonies growing in microcapillaries exhibit one to several central spheres and filaments with tapered ends radiating outward. Stereotyped group can grow to 10 microns in diameter or up to 1 mm. Spheroids can form at the ends of the filaments and can continue to attach to the filaments, whereupon microcolonies of progeny grow around the mother of the definitive population, much like strawberries have their stolons and progeny plants around them. Cells of Metallogenium may reproduce by germination.
In the presence of oxidizable manganese, the microcolonies were light brown to black, the color first appearing in the center of the colony. The oxides of manganese and/or iron then precipitate onto the filaments, increasing the width of the filaments from the base to the top; they can thicken to the point where they join together in the center, forming a densely lobed population. Before light microscopy and staining, it must be treated with oxalic acid (0.2-1.0%) or EDTA, disodium salt (1-2%) to remove metal precipitates. Cells were stained well with carbolic acid gentian violet, but poorly with erythromycin carbolic acid, methylene blue, water-soluble or alcohol-soluble gentian violet or crystal violet.
Metallogenium is a heterotrophic bacterium. Growth is enhanced in the presence of live fungi in artificial media. Pure cultures grow slowly in artificial media; they grow better in mixed microbiomes. Growth can be seen after 4-6 weeks on agar media with ferrous ammonium citrate (1.5 g/L) at pH 6.0-7.8 or on "Novogrudskii water agar". Colonies appear as irregularly shaped brownish dots. No growth was observed on Peptone KNOs agar at pH 7.0. The optimum pH is 6.8-7.0. Manganese compounds are not required, but manganese carbonate and low redox potential are growth-stimulating. Pure cultures can grow in serum-containing media such as those used for Mycoplasma.
Metallogenium is found in the upper layers of freshwater bottom sediments, in freshwater lakes and ponds with plankton, and in microzones of northern hemisphere soils.
Creative Biogene offers customizable Metallogenium strain culture services. This service can help you obtain Metallogenium cultures for subsequent scientific research. This service allows you to skip the complicated and tedious groping of culture conditions, which helps to speed up research on this strain.
The morphology and staining reaction of Metallogenium personatum are the same as those of the genus. Metallogenium personatum reproduces by forming a single spherical cell or array of cells at the tip of the filament. The diameter of the matrix of the bacteria is 0.02-0.3 microns, and the diameter of the filaments is 0.02-0.06 microns. The addition of manganese to the medium promotes filament extension to 12 microns in length. These filaments appear as lateral budding.
Figure 1. Light micrographs of Metallogenium. (Dag Klaveness.1977)
Originally found in the mud of Lake Ukshezero in the southern Karelian SSR. Widely distributed in lake mud, freshwater lake plankton, and southern hemisphere soil.
The filaments of Metallogenium symbioticum do not contain a small matrix to propagate by forming a single bud on the tip or side of the filament. The buds are 0.5 microns in diameter and have shown precipitation of manganese. Grow in culture conditions in the presence of fungi and bacteria. In mixed cultures, the fungus did not form spores normally. Definite colonies develop on the surface and at a distance from the fungal hyphae. It is speculated that the bacteria can parasitize fungi by intracellular growth. Grow well on water agar (2%) containing manganese acetate (0.1 g/L) without added sources of helium and phosphorus. The fungal colony and the symbiotic Metallogenium in between appear as concentric circles. Growth is slow but good in liquid medium containing 2% starch or 1-2% gum arabic plus freshly prepared manganese carbonate, pH 6.2. During the culturing process, the fungal hyphae grow first, and then the culture medium rapidly becomes cloudy due to the appearance of spheroid buds of Metallogenium. These buds produce one or more filaments that become coated with manganese oxide and sink as a precipitate within a few hours. The oxidation of manganese salts was proportional to the growth of symbiotic Metallogenium by direct colony count. Heating at 60°C for 30 minutes resulted in the death of the fungus, but a slow abiotic oxidation of manganese salts would continue; the rate of this oxidation was reduced after transfer to fresh medium.
Metallogenium symbioticum likes mesophilic and aerobic. The optimum pH for growth of this bacterium is 6-8. Originally found in a swamp near Moscow, Russia. Widely distributed in lake mud and soil.
Creative Biogene's fermentation platform has Good Manufacturing Practices (GMP) and can provide customers with a wide range of high-quality microbial fermentation products such as active pharmaceutical ingredients, enzymes and various fine chemicals. In addition, our microbiology experts have completed the transformation and innovation of traditional processes through continuous breakthroughs in key technologies of microbial fermentation processes, and fully contributed to the smooth delivery of the project.
Creative Biogene builds a world-class microbial fermentation technology platform, providing a variety of services from strain screening and optimization to fermentation production and product purification. We have many years of rich experience and provide good technical support for microbial GMP production.
As a leader in microbial production, Creative Biogene has comprehensive production process technology and high-volume manufacturing capabilities. Our goal is to help our customers develop streamlined and controlled manufacturing processes and to support customers throughout the entire product development process, from the R&D stage to market launch.
The culture of Metallogenium requires specific formulations of growth media for use in cloning, plasmid DNA preparation, and protein expression. Creative Biogene offers a selection of bacterial growth media and custom services for your specific application. If you are interested in our microbial anaerobic and aerobic culture platform, please contact us for more details.