scholarly journals Rock traits drive complex microbial communities at the edge of life

2021 ◽  
Author(s):  
CLAUDIA COLEINE ◽  
MANUEL DELGADO BAQUERIZO ◽  
Andrea Zerboni ◽  
Benedetta Turchetti ◽  
Pietro Buzzini ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Iron Concentration ◽  
Thermal Inertia ◽  
Extreme Conditions ◽  
Porous Rocks ◽  
Substrate Heterogeneity ◽  
Quartz Cement ◽  
Rocky Planets ◽  
Endolithic Communities

Antarctic deserts are among the driest and coldest ecosystems of the planet; there, some microbes hang on to life under these extreme conditions inside porous rocks, forming the so-called endolithic communities. Yet, the contribution of distinct rock traits to support complex microbial assemblies remains poorly determined. Here, we combined an extensive Antarctic rock survey with rock microbiome sequencing and ecological networks, and found that contrasting combinations of microclimatic and rock traits such as thermal inertia, porosity, iron concentration and quartz cement can help explain the multiple complex and independent microbial assemblies found in Antarctic rocks. Our work highlights the pivotal role of rocky substrate heterogeneity in sustaining contrasting groups of microorganisms, which is essential to understand life at the edge on Earth, and for searching life on other rocky planets such as Mars.

scholarly journals Thermal Characteristics of New Building Materials and their Effect upon the Energy Efficiency

2008 ◽  
Vol 45 (3) ◽  
pp. 3-13
Author(s):  
J. Ekmanis ◽  
V. Zebergs ◽  
N. Zeltins ◽  
V. Vrublevski
Keyword(s):  
Energy Efficiency ◽  
Heat Capacity ◽  
Thermal Resistance ◽  
Energy Supply ◽  
Heat Supply ◽  
Building Materials ◽  
Thermal Characteristics ◽  
Thermal Inertia ◽  
Extreme Conditions

Thermal Characteristics of New Building Materials and their Effect upon the Energy Efficiency The paper formulates the role of thermal inertia of the building materials in the energy supply of buildings and in solution of the energy efficiency problems. The evolution of construction entails the application of new building materials as well as of glazed surfaces in the envelopes of buildings. An analysis is made of the influence of the thermal resistance of building materials and their heat capacity on the thermal inertia indicators of buildings. An inertia scale of buildings has been developed for the choice of the heat supply capacities of buildings at low outdoor temperatures under extreme conditions of the Latvian climate. The ratio of the ventilation capacities has been analysed in the total heating balance at a low thermal inertia of buildings. The significance of innovative ventilation technologies for raising the energy efficiency has been considered.

scholarly journals Influence of pig farming on human Gut Microbiota: role of airborne microbial communities

Gut Microbes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 1-13
Author(s):  
Julia Moor ◽  
Tsering Wüthrich ◽  
Suzanne Aebi ◽  
Nadezda Mostacci ◽  
Gudrun Overesch ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Microbial Communities ◽  
Human Gut ◽  
Human Gut Microbiota ◽  
Pig Farming

scholarly journals Discovery of novel community-relevant small proteins in a simplified human intestinal microbiome

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannes Petruschke ◽  
Christian Schori ◽  
Sebastian Canzler ◽  
Sarah Riesbeck ◽  
Anja Poehlein ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Intestinal Microbiota ◽  
De Novo ◽  
Bacterial Species ◽  
Intestinal Microbiome ◽  
Single Strain ◽  
Small Proteins ◽  
Human Intestinal Microbiota ◽  
Wide Range

Abstract Background The intestinal microbiota plays a crucial role in protecting the host from pathogenic microbes, modulating immunity and regulating metabolic processes. We studied the simplified human intestinal microbiota (SIHUMIx) consisting of eight bacterial species with a particular focus on the discovery of novel small proteins with less than 100 amino acids (= sProteins), some of which may contribute to shape the simplified human intestinal microbiota. Although sProteins carry out a wide range of important functions, they are still often missed in genome annotations, and little is known about their structure and function in individual microbes and especially in microbial communities. Results We created a multi-species integrated proteogenomics search database (iPtgxDB) to enable a comprehensive identification of novel sProteins. Six of the eight SIHUMIx species, for which no complete genomes were available, were sequenced and de novo assembled. Several proteomics approaches including two earlier optimized sProtein enrichment strategies were applied to specifically increase the chances for novel sProtein discovery. The search of tandem mass spectrometry (MS/MS) data against the multi-species iPtgxDB enabled the identification of 31 novel sProteins, of which the expression of 30 was supported by metatranscriptomics data. Using synthetic peptides, we were able to validate the expression of 25 novel sProteins. The comparison of sProtein expression in each single strain versus a multi-species community cultivation showed that six of these sProteins were only identified in the SIHUMIx community indicating a potentially important role of sProteins in the organization of microbial communities. Two of these novel sProteins have a potential antimicrobial function. Metabolic modelling revealed that a third sProtein is located in a genomic region encoding several enzymes relevant for the community metabolism within SIHUMIx. Conclusions We outline an integrated experimental and bioinformatics workflow for the discovery of novel sProteins in a simplified intestinal model system that can be generically applied to other microbial communities. The further analysis of novel sProteins uniquely expressed in the SIHUMIx multi-species community is expected to enable new insights into the role of sProteins on the functionality of bacterial communities such as those of the human intestinal tract.

scholarly journals The microbial world in a changing environment

2021 ◽  
Vol 94 (1) ◽  
Author(s):  
Rafael Vicuña ◽  
Bernardo González
Keyword(s):  
Climate Change ◽  
Microbial Communities ◽  
Recent Literature ◽  
Public Awareness ◽  
Complete Evaluation ◽  
Microbial World ◽  
Sustainable Environment ◽  
Entire Planet ◽  
New Strategies

Abstract Background In this article we would like to touch on the key role played by the microbiota in the maintenance of a sustainable environment in the entire planet. For obvious reasons, this article does not intend to review thoroughly this extremely complex topic, but rather to focus on the main threats that this natural scenario is presently facing. Methods Recent literature survey. Results Despite the relevance of microorganisms have in our planet, the effects of climate change on microbial communities have been scarcely and not systematically addressed in literature. Although the role of microorganisms in emissions of greenhouse gases has received some attention, there are several microbial processes that are affected by climate change with consequences that are presently under assessment. Among them, host-pathogen interactions, the microbiome of built environment, or relations among plants and beneficial microbes. Conclusions Further research is required to advance in knowledge of the effect of climate change on microbial communities. One of the main targets should be a complete evaluation of the global microbial functional diversity and the design of new strategies to cope with limitations in methods to grow microorganisms in the laboratory. These efforts should contribute to raise a general public awareness on the major role played by the microbiota on the various Earth ecosystems.

The role of porosity in thermal inertia variations on basaltic lavas

Icarus ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 366-369 ◽  
Author(s):  
James R. Zimbelman
Keyword(s):  
Thermal Inertia ◽  
Basaltic Lavas

scholarly journals Towards Oxidatively Stable Emulsions Containing Iron-Loaded Liposomes: The Key Role of Phospholipid-to-Iron Ratio

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1293
Author(s):  
Alime Cengiz ◽  
Karin Schroën ◽  
Claire Berton-Carabin
Keyword(s):  
Oxidative Stability ◽  
Ferrous Sulfate ◽  
Iron Concentration ◽  
Egg Yolk ◽  
Antioxidant Effect ◽  
Crucial Importance ◽  
Fortified Foods ◽  
Oil In Water ◽  
Iron Concentrations

To encapsulate soluble iron, liposomes were prepared using unsaturated phospholipids (phosphatidylcholine from egg yolk), leading to high encapsulation efficiencies (82–99%). The iron concentration affected their oxidative stability: at 0.2 and 1 mM ferrous sulfate, the liposomes were stable, whereas at higher concentrations (10 and 48 mM), phospholipid oxidation was considerably higher. When applied in oil-in-water (O/W) emulsions, emulsions with liposomes containing low iron concentrations were much more stable to lipid oxidation than those added with liposomes containing higher iron concentrations, even though the overall iron concentration was similar (0.1 M). Iron-loaded liposomes thus have an antioxidant effect at high phospholipid-to-iron ratio, but act as pro-oxidants when this ratio is too low, most likely as a result of oxidation of the phospholipids themselves. This non-monotonic effect can be of crucial importance in the design of iron-fortified foods.

scholarly journals Positive Regulation of fur Gene Expression via Direct Interaction of Fur in a Pathogenic Bacterium, Vibrio vulnificus

2007 ◽  
Vol 189 (7) ◽  
pp. 2629-2636 ◽  
Author(s):  
Hyun-Jung Lee ◽  
So Hyun Bang ◽  
Kyu-Ho Lee ◽  
Soon-Jung Park
Keyword(s):  
Gene Expression ◽  
Pathogenic Bacteria ◽  
Vibrio Vulnificus ◽  
Iron Concentration ◽  
Direct Interaction ◽  
Repeated Sequence ◽  
Upstream Region ◽  
Fur Protein

ABSTRACT In pathogenic bacteria, the ability to acquire iron, which is mainly regulated by the ferric uptake regulator (Fur), is essential to maintain growth as well as its virulence. In Vibrio vulnificus, a human pathogen causing gastroenteritis and septicemia, fur gene expression is positively regulated by Fur when the iron concentration is limited (H.-J. Lee et al., J. Bacteriol. 185:5891-5896, 2003). Footprinting analysis revealed that an upstream region of the fur gene was protected by the Fur protein from DNase I under iron-depleted conditions. The protected region, from −142 to −106 relative to the transcription start site of the fur gene, contains distinct AT-rich repeats. Mutagenesis of this repeated sequence resulted in abolishment of binding by Fur. To confirm the role of this cis-acting element in Fur-mediated control of its own gene in vivo, fur expression was monitored in V. vulnificus strains using a transcriptional fusion containing the mutagenized Fur-binding site (fur mt::luxAB). Expression of fur mt::luxAB showed that it was not regulated by Fur and was not influenced by iron concentration. Therefore, this study demonstrates that V. vulnificus Fur acts as a positive regulator under iron-limited conditions by direct interaction with the fur upstream region.

Sign in / Sign up

Export Citation Format

Share Document