scholarly journals Xerotolerance: A New Property in Exiguobacterium Genus

2021 ◽  
Vol 9 (12) ◽  
pp. 2455
Author(s):  
María Castillo López ◽  
Beatriz Galán ◽  
Manuel Carmona ◽  
Juana María Navarro Navarro Llorens ◽  
Juli Peretó ◽  
...  
Keyword(s):  
Deinococcus Radiodurans ◽  
Resistance Mechanism ◽  
Dna Transformation ◽  
Natural Competence ◽  
Transformation Protocol ◽  
Close Relationship ◽  
Complete Set ◽  
First Time ◽  
Siberian Permafrost ◽  
Model Strain

The highly xerotolerant bacterium classified as Exiguobacterium sp. Helios isolated from a solar panel in Spain showed a close relationship to Exiguobacterium sibiricum 255–15 isolated from Siberian permafrost. Xerotolerance has not been previously described as a characteristic of the extremely diverse Exiguobacterium genus, but both strains Helios and 255–15 showed higher xerotolerance than that described in the reference xerotolerant model strain Deinococcus radiodurans. Significant changes observed in the cell morphology after their desiccation suggests that the structure of cellular surface plays an important role in xerotolerance. Apart from its remarkable resistance to desiccation, Exiguobacterium sp. Helios strain shows several polyextremophilic characteristics that make it a promising chassis for biotechnological applications. Exiguobacterium sp. Helios cells produce nanoparticles of selenium in the presence of selenite linked to its resistance mechanism. Using the Lactobacillus plasmid pRCR12 that harbors a cherry marker, we have developed a transformation protocol for Exiguobacterium sp. Helios strain, being the first time that a bacterium of Exiguobacterium genus has been genetically modified. The comparison of Exiguobacterium sp. Helios and E. sibiricum 255–15 genomes revealed several interesting similarities and differences. Both strains contain a complete set of competence-related DNA transformation genes, suggesting that they might have natural competence, and an incomplete set of genes involved in sporulation; moreover, these strains not produce spores, suggesting that these genes might be involved in xerotolerance.

scholarly journals The Turbulent Flow over the BARC Rectangular Cylinder: A DNS Study

2021 ◽  
Author(s):  
Alessandro Chiarini ◽  
Maurizio Quadrio
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
Finite Differences ◽  
Turbulence Models ◽  
Fine Tuning ◽  
Rectangular Cylinder ◽  
Budget Equation ◽  
Complete Set ◽  
First Time

AbstractA direct numerical simulation (DNS) of the incompressible flow around a rectangular cylinder with chord-to-thickness ratio 5:1 (also known as the BARC benchmark) is presented. The work replicates the first DNS of this kind recently presented by Cimarelli et al. (J Wind Eng Ind Aerodyn 174:39–495, 2018), and intends to contribute to a solid numerical benchmark, albeit at a relatively low value of the Reynolds number. The study differentiates from previous work by using an in-house finite-differences solver instead of the finite-volumes toolbox OpenFOAM, and by employing finer spatial discretization and longer temporal average. The main features of the flow are described, and quantitative differences with the existing results are highlighted. The complete set of terms appearing in the budget equation for the components of the Reynolds stress tensor is provided for the first time. The different regions of the flow where production, redistribution and dissipation of each component take place are identified, and the anisotropic and inhomogeneous nature of the flow is discussed. Such information is valuable for the verification and fine-tuning of turbulence models in this complex separating and reattaching flow.

scholarly journals A Meningo-Leucoencephalomyelitis Resembling Visna in Dutch Zwoeger Sheep

1966 ◽  
Vol 3 (5) ◽  
pp. 401-411 ◽  
Author(s):  
A. A. Ressang ◽  
F. C. Stam ◽  
G. F. De Boer
Keyword(s):  
White Matter ◽  
The Netherlands ◽  
Final Stage ◽  
Chronic Condition ◽  
Cerebral Lesions ◽  
Terminal Stage ◽  
Icelandic Sheep ◽  
Close Relationship ◽  
Secondary Demyelination ◽  
First Time

Zwoegerziekte is a disease in Dutch sheep which morphologically closely resembles an Icelandic sheep disease, Maedi2. Chronic lung affection and emaciation are the principal symptoms of both diseases. Visna is another chronic condition in Icelandic sheep affecting mainly the C.N.S. A virus has been isolated from sheep affected with Maedi or Visna and a close relationship in properties has been found between both viruses. In two Dutch sheep autopsied in the final stage of Zwoegerziekte, lesions were present in the C.N.S., which histologically resembled those in Visna. Another sheep slaughtered at the municipal abattoir, with lung lesions characteristic for the terminal stage of Zwoegerziekte, exhibited early cerebral lesions resembling Visna. The lesions in the C.N.S. of these three sheep were meningitis and severe encephalomyelitis of the glial type affecting the white matter. Secondary demyelination was striking. Though Zwoegerziekte has been known for several decades in the Netherlands, the accompanying C.N.S. lesions are described for the first time.

Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2257-2266 ◽  
Author(s):  
Helmuth Adelsberger ◽  
Christian Hertel ◽  
Erich Glawischnig ◽  
Vladimir V. Zverlov ◽  
Wolfgang H. Schwarz
Keyword(s):  
Extracellular Enzymes ◽  
Enzyme System ◽  
Thermophilic Bacterium ◽  
Recombinant Enzymes ◽  
Type Mode ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of

Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), β-xyloside (bxlA, bxlB, bglZ) and α-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.

scholarly journals Characterization of Each St and Y Genome Chromosome of Roegneria grandis Based on Newly Developed FISH Markers

2021 ◽  
pp. 213-222
Author(s):  
Dandan Wu ◽  
Xiaoxia Zhu ◽  
Lu Tan ◽  
Haiqin Zhang ◽  
Lina Sha ◽  
...  
Keyword(s):  
Structural Changes ◽  
Distribution Patterns ◽  
Proximal Region ◽  
Genome Chromosome ◽  
High Affinity ◽  
Complete Set ◽  
Genome Analyses ◽  
First Time ◽  
Homoeologous Chromosomes

The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of <i>Roegneria</i> C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among <i>Roegneria</i> species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of <i>R. grandis</i> (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.

Atrial fibrillation is associated with high levels of monocyte-platelet-aggregates and increased CD11b expression in patients with aortic stenosis

2016 ◽  
Vol 115 (05) ◽  
pp. 993-1000 ◽  
Author(s):  
Katharina Berndt ◽  
Sandy Wydra ◽  
Daniel Tarnowski ◽  
Peggy Barthel ◽  
Silvio Quick ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Cd11b Expression ◽  
Flow Cytometric ◽  
High Prevalence ◽  
Close Relationship ◽  
Enhanced Expression ◽  
Quantification Analysis ◽  
Inflammatory Processes ◽  
Platelet Aggregates ◽  
First Time

SummaryA growing body of evidence suggests a pivotal role of inflammatory processes in AF in a bidirectional manner. Infiltrating leukocytes seem to promote both structural and electrical remodelling processes in patients with AF. Monocyte-platelets-aggregates (MPAs) are sensitive markers of both platelets and monocyte activation. So far it is not clear whether the content of MPAs is affected by AF. The present study examined the content of MPAs and the activation of monocytes in elderly patients with an aortic stenosis in dependence of AF. These patients are known to have a high prevalence of AF. Flow-cytometric quantification analysis demonstrated that patients with AF have an increased content of MPAs (207 ± 13 cells/μl vs 307 ± 21 cells/μl, p<0.001), and enhanced expression of CD11b on monocytes (p<0.001), compared to patients in stable sinus rhythm (SR). The number of CD14+/CD16+ monocytes were only slightly elevated in patients with AF. These findings were seen in patients with permanent AF. But also patients with paroxysmal AF, even when presenting in SR, the MPAs were increased by 50 % (p<0.05) as well as the CD11b expression, which was twice as high (p<0.05) compared to stable SR. These results demonstrate for the first time a dependency of MPAs and CD11b expression on monocytes in the presence of AF and support the notion of a close relationship between AF, thrombogenesis and inflammation. The content of MPAs and the extent of activation on monocytes appear promising as biomarkers for paroxysmal AF and as possible future targets for developing novel pharmacological therapeutic strategies.Supplementary Material to this article is available online at www.thrombosis-online.com.

scholarly journals Expression of a Cryptic Secondary Sigma Factor Gene Unveils Natural Competence for DNA Transformation in Staphylococcus aureus

2012 ◽  
Vol 8 (11) ◽  
pp. e1003003 ◽  
Author(s):  
Kazuya Morikawa ◽  
Aya J. Takemura ◽  
Yumiko Inose ◽  
Melody Tsai ◽  
Le Thuy Nguyen Thi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sigma Factor ◽  
Dna Transformation ◽  
Natural Competence ◽  
Factor Gene

Static Multiaxial Fracture Behavior of Graphite Components: A Review of Recent Results

2017 ◽  
Vol 754 ◽  
pp. 35-38 ◽  
Author(s):  
S.M.J. Razavi ◽  
M. Peron ◽  
J. Torgersen ◽  
F. Berto
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Fracture Behavior ◽  
Local Strain ◽  
Opening Angle ◽  
Mode Mixity ◽  
Static Tests ◽  
Complete Set ◽  
Tip Radius ◽  
First Time

The problem of mixed mode (I+III) brittle fracture of polycrystalline graphite is investigated systematically here for the first time. The present study considers cylindrical specimens weakened by circumferential notches characterized by different acuities. A new complete set of experimental data is provided considering different geometrical configurations by varying the notch opening angle and the notch tip radius. The multiaxial static tests have been performed considering different values of the mode mixity ratio. A criterion based on the local Strain Energy Density previously applied by the same authors only to pure modes of loading is extended here to the case of tension and torsion loadings applied in combination.

Deposition-induced effects of isotactic polypropylene and polycarbonate composites during fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 869-880 ◽  
Author(s):  
Ying-Guo Zhou ◽  
Bei Su ◽  
Lih-sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Fused Deposition Modeling ◽  
Content Type ◽  
Fused Deposition ◽  
Close Relationship ◽  
Molded Parts ◽  
Deposition Modeling ◽  
Injection Molded ◽  
First Time

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

Ascomycetes (Fungi) from the relic forest of Fagus grandifolia subsp. mexicana in eastern Mexico

Phytotaxa ◽  
2019 ◽  
Vol 418 (1) ◽  
pp. 1-41
Author(s):  
TANIA RAYMUNDO ◽  
RICARDO VALENZUELA ◽  
YENITZE GARCÍA-MARTÍNEZ ◽  
MARCO ANTONIO BRAVO-ÁLVAREZ ◽  
JULIO CÉSAR RAMÍREZ-MARTÍNEZ ◽  
...  
Keyword(s):  
Tree Species ◽  
New Records ◽  
Cloud Forest ◽  
Fagus Grandifolia ◽  
Tropical Montane Cloud Forest ◽  
Forest Patch ◽  
Montane Cloud Forest ◽  
Close Relationship ◽  
Decaying Wood ◽  
First Time

An intensive recollection of Ascomycetes was carried out within the best-known preserved Mexican tropical montane cloud forest patch dominated by Fagus grandifolia subsp. mexicana. This relict tree species has a fragmented and restricted distribution in the mountains of eastern Mexico. Other Mexican endemic Fagaceae species show dominance in this forest patch. Historically, records of Ascomycetes fungi in this type of forest are scarce. The present study found 170 specimens belonging to 61 species, of which 30 are new records for the state, while 10 species are cited for the first time in the country. Most of the recorded Ascomycetes species are intimately associated to Fagaceae tree species (Fagus and Quercus). From these, many are endophytes belonging to the Order Xylariales, while others grow on decaying wood, fallen branches, leaves and/or litter (possibly mycorrhizal). This interesting close relationship between fungi and Fagaceae trees must be studied and analyzed.

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