Search results for "microbial"

The effect of spent bleaching earth ageing process on its physicochemical and microbial composition and its potential use as a source of fatty acids …

2014

This study was aimed at investigating the physicochemical and microbiological changes that took place during the ageing process of spent bleaching earth in the presence of autochthonous microorganisms. Research material included fresh spent bleaching earth (SBE0) and the same material after 3 years of storage at the constant temperature of 20 °C, without aeration and moistening (SBE3). Changes in the chemical composition of analysed waste material were observed during its ageing process point to a spontaneous bioconversion of fat substance towards formation and/or release of free saturated fatty acids C16:0 and C18:0 (14.3 g 100 g(-1) D.M.), triterpenes (8.48 g 100 g(-1) D.M.), cholesterol …

Freshwater organisms that build stromatolites: a synopsis of biocrystallization by prokaryotic and eukaryotic algae

1998

In freshwater environments such as river and stream bottoms, rocks and submerged vegetation are covered with a biological felt (also called a periphyton, microbial mat, biofilm, etc.) that is susceptible to calcification. Compilation of an extensive bibliography and our own observations have allowed the identification of 44 species of Coccogonophyceae, 122 Hormogonophyceae, 2 Chrysophyceae, 35 Chlorophyceae, 3 Xanthophyceae, 2 diatoms, and 3 Rhodophyceae that grow on calcareous tufa and coat vegetation. Diverse genera include species that are also calcified but impossible to determine because they lack reproductive organs. Crystals have been described from 74 species in the literature and w…

Cold-active molecules for a sustainable preservation and restoration of historic-artistic manufacts

2016

In the last decades biotechnology research provides sustainable alternatives to traditional procedures for preventive preservation of cultural assets. Recently, bioactive molecules (BMs) isolated from marine invertebrate organisms have been isolated and tested for bioremoval of protein layers (BMP) or to controlling microbial colonization (BMA), acting at temperature lower than 30°C. The Protease or Antimicrobial activity was tested on ad hoc assembled specimens and on different historic-artistic manufacts. In bio-removing protocol BMP molecules were applied as gelled solutions, in order to guarantees a selective action, respectful of constitutive materials and manufact integrity. Peculiari…

Biotechnology: Innovative Contributions to the Conservation and Restoration of Cultural Heritage

2014

As exhaustively showed during the conference "Molecular Biology and Cultural Heritage", held in Seville in 2003, molecular biology represents an important source of insight for the development of innovative protocols for the detection and characterization of microbial consortia colonizing historic-artistic manufacts. In particular, fungi and bacteria (frequently associated with green algae, cyanobacteria, lichens, etc), wide-spread in biosphere environments, are the main biological systems related to deterioration of cultural asset. Moreover in the aerosol of indoor environments, whre the manufacts are exposed or stored, complex microbiai communities may release some molecules with human (v…

Mapping and determinism of soil microbial community distribution across an agricultural landscape.

2015

Article en open access; International audience; Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13km(2). Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution…

Novel antimicrobial and anti-biofilm agents from a marine invertebrate

2011

Implication of the biofilm ageing for the settlement of the vermetid gastropod Dendropoma cristatum (Biondi 1857)

2016

Dendropoma cristatumreefs are key-intertidal habitats of the central Mediterranean. Knowledge onD. cristatumbiology is presently scant, particularly on its early life stage. The development of embryos occurs inside the maternal shell, and the crawling larvae settle on hard substrates shortly after hatching. Epilithic biofilm is known to have implications in the settlement of many marine invertebrates; however whether biofilm plays a role in driving the vermetid settlement is unknown. In this study the microbial assemblage ageing is tested as apotentialtriggerforD. cristatumsettlement. A field experiment was set-up to compare the larval settlement rate on removable limestone cubes (5x5x2 cm)…

Modeling the Response of the Planktonic Microbial Community to Warming Effects in Maritime Antarctic Lakes

2014

Abstract In this chapter, we describe the design and prognoses given by the simulation of an ecological model dealing with the functioning of the microbial community of a maritime Antarctic lake, whose main ecological features are also reported. The model is based on carbon fluxes through the planktonic community and the carbon subsides from the benthic mosses covering the lake bottom and microbial mats spread over the lake’s catchment. It describes the dynamics of the bacterioplankton, phytoplankton, and organic matter, both particulate and dissolved, during the austral summer, with temperature and solar radiation as the main forcing functions driving the response of the modeled state vari…

Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea off Vulcano, Italy.

2014

The effects of increasing atmospheric CO2 on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO2 gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 mu atm, minimum Omega(arag) 3.77), moderately CO2-enriched (median pCO(2) 592 mu atm, minimum Omega(arag) 2.96), and highly CO2-enriched (median pCO(2) 1611 mu at…

2018

AbstractWhile significant efforts have been invested in reconstructing the early evolution of the Earth’s atmosphere–ocean–biosphere biogeochemical nitrogen cycle, the potential role of an early continental contribution by a terrestrial, microbial phototrophic biosphere has been largely overlooked. By transposing to the Archean nitrogen fluxes of modern topsoil communities known as biological soil crusts (terrestrial analogs of microbial mats), whose ancestors might have existed as far back as 3.2 Ga ago, we show that they could have impacted the evolution of the nitrogen cycle early on. We calculate that the net output of inorganic nitrogen reaching the Precambrian hydrogeological system c…