scholarly journals Degradation of Poly(ε-caprolactone) by a Thermophilic Community and Brevibacillus thermoruber Strain 7 Isolated from Bulgarian Hot Spring

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1488
Author(s):  
Nikolina Atanasova ◽  
Tsvetelina Paunova-Krasteva ◽  
Stoyanka Stoitsova ◽  
Nadja Radchenkova ◽  
Ivanka Boyadzhieva ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Control Sample ◽  
Community Control ◽  
Pure Strain ◽  
Plastic Properties ◽  
Biodegradation Process ◽  
Promising Application ◽  
Taxonomic Groups

The continual plastic accumulation in the environment and the hazardous consequences determine the interest in thermophiles as possible effective plastic degraders, due to their unique metabolic mechanisms and change of plastic properties at elevated temperatures. PCL is one of major biodegradable plastics with promising application to replace existing non-biodegradable polymers. Metagenomic analysis of the phylogenetic diversity in plastic contaminated area of Marikostinovo hot spring, Bulgaria revealed a higher number taxonomic groups (11) in the sample enriched without plastic (Marikostinovo community, control sample, MKC-C) than in that enriched in the presence of poly-ε-caprolactone (PCL) (MKC-P), (7). A strong domination of the phylum Proteobacteria was observed for MKC-C, while the dominant phyla in MKC-P were Deinococcus-Thermus and Firmicutes. Among the strains isolated from MKC-P, the highest esterase activity was registered for Brevibacillus thermoruber strain 7 at 55 °C. Its co-cultivation with another isolate resulted in ~10% increase in enzyme activity. During a 28-day biodegradation process, a decrease in PCL molecular weight and weight loss were established resulting in 100% degradation by MKC-P and 63.6% by strain 7. PCL degradation intermediate profiles for MKC-P and pure strain were similar. Broken plastic pieces from PCL surface and formation of a biofilm by MKC-P were observed by SEM, while the pure strain caused significant deformation of PCL probes without biofilm formation.

scholarly journals Nucleic acid cleavage with a hyperthermophilic Cas9 from an uncultured Ignavibacterium

2019 ◽  
Vol 116 (46) ◽  
pp. 23100-23105 ◽  
Author(s):  
Stephanie Tzouanas Schmidt ◽  
Feiqiao Brian Yu ◽  
Paul C. Blainey ◽  
Andrew P. May ◽  
Stephen R. Quake
Keyword(s):  
Dna Cleavage ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Metagenomic Sequencing ◽  
Rna Seq ◽  
Bacterial Rna ◽  
Acid Cleavage ◽  
Cas9 Protein ◽  
Ribosomal Rrna

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) systems have been effectively harnessed to engineer the genomes of organisms from across the tree of life. Nearly all currently characterized Cas9 proteins are derived from mesophilic bacteria, and canonical Cas9 systems are challenged by applications requiring enhanced stability or elevated temperatures. We discovered IgnaviCas9, a Cas9 protein from a hyperthermophilic Ignavibacterium identified through mini-metagenomic sequencing of samples from a hot spring. IgnaviCas9 is active at temperatures up to 100 °C in vitro, which enables DNA cleavage beyond the 44 °C limit of Streptococcus pyogenes Cas9 (SpyCas9) and the 70 °C limit of both Geobacillus stearothermophilus Cas9 (GeoCas9) and Geobacillus thermodenitrificans T12 Cas9 (ThermoCas9). As a potential application of this enzyme, we demonstrate that IgnaviCas9 can be used in bacterial RNA-seq library preparation to remove unwanted cDNA from 16s ribosomal rRNA without increasing the number of steps, thus underscoring the benefits provided by its exceptional thermostability in improving molecular biology and genomic workflows. IgnaviCas9 is an exciting addition to the CRISPR-Cas9 toolbox and expands its temperature range.

PRESERVATION OF FOSSIL MICROBES AND BIOFILM IN CAVE POOL CARBONATES AND COMPARISON TO OTHER MICROBIAL CARBONATE ENVIRONMENTS

Palaios ◽  
2016 ◽  
Vol 31 (4) ◽  
pp. 177-189 ◽  
Author(s):  
LESLIE A. MELIM ◽  
DIANA E. NORTHUP ◽  
PENELOPE J. BOSTON ◽  
MICHAEL N. SPILDE
Keyword(s):  
Organic Material ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Cold Seep ◽  
Alternative Mode ◽  
Photolytic Degradation ◽  
Microbial Carbonate ◽  
Edx Analyses ◽  
Uniform Diameter

Abstract Fossil microbes are generally preserved by authigenic minerals, including silica, apatite, iron minerals, clays, and carbonates. An alternative mode of preservation by entombment in calcite, without replacement, has been identified in carbonate cave pool microbialites that were etched and examined in the scanning electron microscope (SEM). Features identified include filaments, threads, and films that show excess carbon in energy dispersive X-ray (EDX) analyses, suggesting preservation of organic matter. Filaments are single smooth or reticulated strands with curving string-like morphology, often hollow, and with a uniform diameter of 0.5 to 1.0 μm. Threads, in contrast, are variable thickness, from several microns down to 0.1 μm, always solid, and commonly branch. Films are thin (< 1 μm) drapes associated with threads. Filaments are interpreted as microbial filaments, while threads and films are interpreted as preserved extracellular polymeric substance (EPS). In addition, microbial filaments and EPS are only revealed via acid etching, suggesting preservation of organic material by entombment, not by replacement with calcite. To determine whether entombed microbes are a common feature of carbonate microbialites that form in different environmental settings, samples of hot spring travertine, caliche soil, and reef microbialite were examined. Whereas the travertine samples were barren, entombed EPS was found in the caliche soil and the reef microbialite; the latter also contained a few entombed filaments. In addition, entombed microbial material has been reported from carbonate cold seep deposits. Such findings indicate that entombment of microbes and EPS in carbonates is not restricted to cave settings, but is more widespread than previously reported. Possible causes for the lack of preservation in travertines include rapid degradation of microbial material either by sunlight due to photolytic degradation, aerobic microbial degradation, detritivore consumption, or elevated temperatures. Rapid carbonate precipitation is ruled out as, somewhat surprisingly, preservation is better in slower growing cave carbonates than in rapidly growing travertines. Potential long-term preservation of organic material entombed in carbonate has implications for the characterization of fossil microbial communities using molecular biomarkers and the search for life on other planets.

Process Design for Superalloys Sheet Rotary Forming

2020 ◽  
Vol 985 ◽  
pp. 91-96
Author(s):  
Krzysztof Zaba ◽  
Sandra Puchlerska ◽  
Tomasz Pieja ◽  
Jaroslaw Pyzik
Keyword(s):  
Process Design ◽  
Elevated Temperatures ◽  
Nickel Superalloy ◽  
Inconel 625 ◽  
Quality Factors ◽  
Forming Process ◽  
Plastic Properties ◽  
Temperature Oxidation ◽  
Wide Range ◽  
The Impact

Inconel 625 is a nickel superalloy, characterized by high fatigue strength. The alloy is resistant to a wide range of corrosive environments, including high-temperature oxidation. For this reason, it is an attractive material for the chemical, shipbuilding and aviation industries. Inconel 625 alloy is designed for plastic working. However, the significant difficulty is the appropriate process design, due to the high deformation resistance. In order to improve the plastic properties of the alloy, processing at elevated temperatures is practiced. In this work, attempts were made to implement rotary forming process of Inconel 625 superalloy. For this purpose, an experiment was designed, investigating the impact of three variables on the process – feed rate, spinning rate and heating. For the tests were used Inconel 625 metal plates in the shape of discs. Axial-symmetrical products were formed, using a spinning machine. The geometry of the products according to selected quality factors was investigated. Optimal process parameters were chosen using multivariate statistical optimization. These parameters will be used to set up processes to obtain product that meets quality requirements.

scholarly journals High Potential for Biomass-Degrading Enzymes Revealed by Hot Spring Metagenomics

2021 ◽  
Vol 12 ◽  
Author(s):  
Nicholas J. Reichart ◽  
Robert M. Bowers ◽  
Tanja Woyke ◽  
Roland Hatzenpichler
Keyword(s):  
Hot Springs ◽  
Elevated Temperatures ◽  
Plant Biomass ◽  
Hot Spring ◽  
Enzyme Stability ◽  
Taxonomic Diversity ◽  
Future Research ◽  
Protein Chemistry ◽  
Glycosyl Hydrolases ◽  
Degrading Enzymes

Enzyme stability and activity at elevated temperatures are important aspects in biotechnological industries, such as the conversion of plant biomass into biofuels. In order to reduce the costs and increase the efficiency of biomass conversion, better enzymatic processing must be developed. Hot springs represent a treasure trove of underexplored microbiological and protein chemistry diversity. Herein, we conduct an exploratory study into the diversity of hot spring biomass-degrading potential. We describe the taxonomic diversity and carbohydrate active enzyme (CAZyme) coding potential in 71 publicly available metagenomic datasets from 58 globally distributed terrestrial geothermal features. Through taxonomic profiling, we detected a wide diversity of microbes unique to varying temperature and pH ranges. Biomass-degrading enzyme potential included all five classes of CAZymes and we described the presence or absence of genes encoding 19 glycosyl hydrolases hypothesized to be involved with cellulose, hemicellulose, and oligosaccharide degradation. Our results highlight hot springs as a promising system for the further discovery and development of thermo-stable biomass-degrading enzymes that can be applied toward generation of renewable biofuels. This study lays a foundation for future research to further investigate the functional diversity of hot spring biomass-degrading enzymes and their potential utility in biotechnological processing.

scholarly journals In Vitro and In Silico Evaluation of Biological Activity of a New Series of Oxadiazole Compounds Against Esp Gene Expression in Enterococcus faecalis Biofilm

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Sepideh Ghameshlouei ◽  
Nakisa Zarrabi Ahrabi ◽  
Yasin SarveAhrabi
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Biological Activities ◽  
Control Sample ◽  
Surface Protein ◽  
Bacterial Biofilm ◽  
Receptor Binding Site ◽  
Wide Range ◽  
Oxadiazole Derivatives ◽  
The Impact

Background: The enterococcal surface protein (Esp) is a high-molecular-weight surface protein of biofilm creating agent in Enterococcus faecalis. Oxadiazoles have a wide range of biological activities. Objective: This research aimed to examine the impact of new oxadiazole derivatives on the expression of Esp, playing an important role in promoting the biofilm formation ability of drug-resistant E. faecalis strains. Method: 1, 3, 4-oxadiazole derivatives were synthesized through a one-step synthesis. E. faecalis strains were collected and isolated from hospitals in Tehran. The antimicrobial properties of the synthesized materials against the isolated strains were investigated. RNA, DNA, and cDNA were extracted, and the relative expression of Esp in E. faecalis isolates was evaluated by real-time PCR. Docking study was performed by AutoDock vina software, and the resulting docking poses were analyzed using Discovery Studio 4.5 Client software. Results: The use of synthesized derivatives changed the Esp expression level in different isolates compared to the control sample. The two compounds containing naphthalene (4f) and methoxyphenyl (4g) caused respectively a 2-fold and a 3-fold decrease in Esp expression compared to the control sample. The compound 4f with the best binding energy among the compounds (-9.2) had the most hydrogen and hydrophobic bonds with the receptor-binding site. Conclusions: 1, 3, 4-oxadiazole derivatives, especially naphthalene and methoxyphenyl, act as inhibitors of bacterial biofilm formation and can be used in the pharmaceutical and biological industries.

scholarly journals The Heat-Induced Molecular Disaggregase Hsp104 of Candida albicans Plays a Role in Biofilm Formation and Pathogenicity in a Worm Infection Model

2012 ◽  
Vol 11 (8) ◽  
pp. 1012-1020 ◽  
Author(s):  
Alessandro Fiori ◽  
Soňa Kucharíková ◽  
Gilmer Govaert ◽  
Bruno P. A. Cammue ◽  
Karin Thevissen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Stress Responses ◽  
Biofilm Formation ◽  
Fungal Pathogens ◽  
Elevated Temperatures ◽  
Structural Defects ◽  
Infection Model ◽  
Content Type

ABSTRACT The consequences of deprivation of the molecular chaperone Hsp104 in the fungal pathogen Candida albicans were investigated. Mutants lacking HSP104 became hypersusceptible to lethally high temperatures, similarly to the corresponding mutants of Saccharomyces cerevisiae , whereas normal susceptibility was restored upon reintroduction of the gene. By use of a strain whose only copy of HSP104 is an ectopic gene under the control of a tetracycline-regulated promoter, expression of Hsp104 prior to the administration of heat shock could be demonstrated to be sufficient to confer protection from the subsequent temperature increase. This result points to a key role for Hsp104 in orchestrating the cell response to elevated temperatures. Despite their not showing evident growth or morphological defects, biofilm formation by cells lacking HSP104 proved to be defective in two established in vitro models that use polystyrene and polyurethane as the substrates. Biofilms formed by the wild-type and HSP104 -reconstituted strains showed patterns of intertwined hyphae in the extracellular matrix. In contrast, biofilm formed by the hsp104 Δ/ hsp104 Δ mutant showed structural defects and appeared patchy and loose. Decreased virulence of the hsp104 Δ/ hsp104 Δ mutant was observed in the Caenorhabditis elegans infection model, in which high in vivo temperature does not play a role. In agreement with the view that stress responses in fungal pathogens may have evolved to provide niche-specific adaptation to environmental conditions, these results provide an indication of a temperature-independent role for Hsp104 in support of Candida albicans virulence, in addition to its key role in governing thermotolerance.

scholarly journals Effect of salt and temperature stresses on survival and infectivity of Heterorhabditis spp. IJs

Nematology ◽  
1999 ◽  
Vol 1 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Michelle M. Finnegan ◽  
Martin J. Downes ◽  
Myra O'Regan ◽  
Christine T. Griffin
Keyword(s):  
High Temperature ◽  
Nous Avons ◽  
Elevated Temperatures ◽  
Galleria Mellonella ◽  
High Salinity ◽  
Sea Water ◽  
Aqueous Suspension ◽  
North West ◽  
The North ◽  
Taxonomic Groups

Abstract Heterorhabditis is frequently found in coastal sandy soils where it may experience both high salinity and high temperatures. We tested the ability of infective juveniles (IJs) of three taxonomic groups of Heterorhabditis to infect insects in saline sand. We also tested whether salinity (sea water) affected the IJs' ability to tolerate elevated temperatures in aqueous suspension and in sand. IJs of all three taxonomic groups killed Galleria mellonella in saline sand (25.6% insects killed), but at a lower level than in non-saline sand (96.5% insects killed). Exposure of IJs in sand to high temperature reduced their ability to kill G. mellonella at 20 degrees C; heating IJs in saline sand reduced G. mellonella mortality to a lesser extent (25.6% at 20 degrees C, 18.3% at 39 degrees C) than heating in non-saline sand (96.5% at 20 degrees C, 17.5% at 39 degrees C). In aqueous suspension, IJs of the North-West European and Irish types of Heterorhabditis tolerated high temperature better in sea water (at least 95% survived 1 h at 39 C) than in distilled water (none survived 1 h at 38 degrees C). H. bacteriophora was more temperature tolerant: survival and subsequent infectivity of IJs was unaffected by temperature up to 39 degrees C in either medium. It was concluded that high salinity (sea water) reduces the ability of Heterorhabditis IJs to infect, but improves their tolerance of high temperature. Effets des chocs dus a la salinite et a la temperature sur la survie et l'infestivite des juveniles infestants d' Heterorhabditis spp. - Les Heterorhabditis sont frequemment rencontres dans les sols sableux cotiers ou ils peuvent etre soumis a des salinites et des temperatures elevees. Nous avons teste la capacite des juveniles infestants (IJs) de trois groupes taxinomiques d'Heterorhabditis a infester des insectes dans du sable sale. Nous avons aussi cherche a savoir si la salinite (eau de mer) affecte la capacite des IJs a tolerer des temperatures elevees, soit en suspension aqueuse, soit dans du sable. Les IJs des trois troupes taxinomiques tuent les Galleria mellonella dans le sable sale, mais a un taux plus faible que dans le sable non sale (25,6 contre 96,5% des insectes tues). L'exposition des IJs dans du sable a des temperatures elevees reduit leur capacite a tuer G. mellonella a 20 degrees C; le chauffage des IJs dans du sable sale reduit la mortalite des G. mellonella dans un moindre mesure (25,6 a 20 degrees C contre 18,3% a 39 degrees C) que dans du sable non sale (96,5% a 20 degrees C contre 17,5% a 39 degrees C). En suspension aqueuse, les IJs des types Europe du nord-ouest et d'Irlande tolerent mieux les temperatures elevees dans l'eau de mer (au moins 95% survivent 1 h a 39 degrees C) que dans l'eau distillee (aucune survie apres 1 h a 38 degrees C). H. bacteriophora montre la meilleure tolerance a la temperature: la survie et l'infestivite ulterieures des IJs ne sont pas affectees par la temperature jusqu'a 39 degrees C dans l'un et l'autre milieux. Il en est conclu que les salinites elevees (eau de mer) reduisent la capacite d'infestation des IJs d'Heterorhabditis, mais ameliorent leur tolerance aux temperatures elevees.

scholarly journals The Process of Regenerative Heat Treatment of the Valve Chamber of the Steam Turbine

2019 ◽  
Vol 26 (3) ◽  
pp. 243-248
Author(s):  
Agata Wieczorska
Keyword(s):  
Steam Turbine ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Cast Steel ◽  
Degradation Process ◽  
Steam Turbines ◽  
Regenerative Heat ◽  
Plastic Properties ◽  
Term Operation ◽  
Dynamic Damage

Abstract Steel castings are often used in the construction of valve chambers of steam turbines. Stringent requirements are set due to the continuous operation of the material at elevated temperatures, in the order of 300°C to 600°C. The material of the valve chamber must be resistant to fatigue-creep changes as well as corrosion. This material must be also resistant to dynamic damage which occures when the turbine is starting and stopping. Dynamic damage is induced by a short-lasting but intense accumulation of localized stresses. The castings of the valve chambers of the steam turbine are usually made from the “three-component” type CrMoV-cast steel. Mentioned castings of the valve chamber are continuously subjected to high temperatures, either constant and periodically variable stresses. Due to this, the degradation process of material of the castings is taking place. It is caused by physicochemical processes such as: creep, relaxation, thermal fatigue, corrosion, erosion and changes in material properties, e.g. displacement of the critical point of brittleness. Finally, first cracks and deformations can be observed in the material during the operation. The art presents the process of revitalization technology of the steam turbine valve chamber which was subjected to long-term operation at high temperatures. The revitalization process is aimed at improving the plastic properties of the material and, as the result, extending its service life. The research presented in the article show that impact strength of the chamber material after revitalization is very high. Also the strength properties of the valve chamber, after revitalization, are high and in line with the requirements. The study show that the revitalization of the valve chamber was carried out correctly and restored the material to plastic deformation.

Vulnerability to Narcotic Addiction: Preliminary Findings

1994 ◽  
Vol 24 (2) ◽  
pp. 293-314 ◽  
Author(s):  
David N. Nurco ◽  
Mitchell B. Balter ◽  
Timothy Kinlock
Keyword(s):  
Retrospective Study ◽  
Sampling Methods ◽  
Historical Data ◽  
Control Sample ◽  
Community Control ◽  
Control Groups ◽  
Fieldwork Experience ◽  
Narcotic Addiction ◽  
Community Controls

This is a report of fieldwork methodology and preliminary findings from a controlled retrospective study of vulnerability to narcotic addiction comparing three groups of males closely matched by neighborhood, age, and race: a community-wide sample of narcotic addicts; a nonaddicted control sample of age-eleven peer associates of the addicts; and a nonaddicted community control sample of age-eleven peers who did not associate with the addicts. Fieldwork experience and preliminary findings suggest a strong selective association between friendship and deviance among narcotic addicts and their age-eleven associates — a relationship that is much less common in the two control groups, particularly community controls. Association with older deviants was also more characteristic of addicts than for the peer or community controls. Experience in the study also attests to the feasibility and merit of capturing historical data via retrospective, reconstructive sampling methods.

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