1,720,963 research outputs found
Mutagenesis and screening for cellulase (endo-1,4-b-D-glucanase) deficient strains of the white-rot basidiomycete Trametes trogii Berk
No full textSensitivity to UV treatment and nuclear size of mycoplasma-like organism infected Humicola sp.
No full text
Consolidamento di pietra calcarea indotto da batteri calcificanti: applkicazioni nel recupero e nella conservazione dei Beni Culturali
No full textFilogenesi dei sistemi di fissazione dell'azoto atmosferico ed implicazioni ecologiche ed agronomiche nel suo assetto attuale
No full textCalcium carbonate precipitation by bacterial strains isolated from a limestone cave and from a loamy soil
No full textTo study the role of calcifying bacteria in monument protection, 31 calcifying bacterial
strains were isolated from natural habitats: 64% were of the genus Bacillus, 16% of
the genus Arthrobacter, and 2 of the remaining isolates were identified as Kingella and
Xanthomonas. The ability to form CaCO3 crystals, the extent of the precipitation, and the
type of crystals formed were determined at incubation temperatures of 4, 22, and 32±C.
The highest of these temperatures favored CaCO3 formation. Most of the bacteria precipitated
CaCO3 in the form of calcite. This activity was strictly controlled by the growth
of microbial colonies on a solid substrate. The role of the calcifying bacteria in natural
precipitation of carbonates is discussed. Further experiments are in progress in order
to select the most suitable bacterial strains for a controlled production of calcareous
crusts.
Keywords adobe, biomineralization, calcifying bacteria, calcite precipitation, historic
monument protection, historic monument restoratio
Batterizzazione di leguminose da foraggio e da granella: un triennio di ricerche in Italia.
No full textRhizobia as inoculants for field trials in marginal soils of middle- and northern- Italy
No full textInvolvement of microorganisms in the formation of carbonate speleothems in the Cervo Cave (L'Aquila-Italy)
No full textMuch is known about the bacterial precipitation of carbonate
rocks, but comparatively little is known about the involvement of
microbes in the formation of secondary mineral structures in caves.
We hypothesized that bacteria isolated from calcareous stalactites,
which are able to mediate CaCO3 precipitation in vitro, play a role
in the formation of carbonate speleothems.We collected numerous
cultivable calcifying bacteria from calcareous speleothems from
Cervo cave, implying that their presence was not occasional. The
relative abundance of calcifying bacteria among total cultivable
microflora was found to be related to the calcifying activity in
the stalactites. We also determined the δ13C and δ18O values of
the Cervo cave speleothems from which bacteria were isolated and
of the carbonates obtained in vitro to determine whether bacteria
were indeed involved in the formation of secondary mineral structures.
We identified three groups of biological carbonates produced
in vitro at 11◦C on the basis of their carbon isotopic composition:
carbonates with δ13C values (a) slightly more positive, (b) more
negative, and (c) much more negative than those of the stalactite
carbonates. The carbonates belonging to the first group, characterized
by the most similar δ13C values to stalactites, were produced
by the most abundant strains. Most of calcifying isolates belonged
to the genus Kocuria. Scanning electron microscopy showed that
dominant morphologies of the bioliths were sherulithic with fibrous
radiated interiors. We suggest a mechanism of carbonate crystal
formation by bacteria
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