Alkalithermophiles

2004 ◽  
Vol 32 (2) ◽  
pp. 193-198 ◽  
Author(s):  
J. Wiegel ◽  
V.V. Kevbrin
Keyword(s):  
High Temperature ◽  
Environmental Parameters ◽  
Great Majority ◽  
Growth Conditions ◽  
Model Organisms ◽  
Extraterrestrial Life ◽  
Soils And Sediments ◽  
Alkaline Environments ◽  
Micro Organisms ◽  
Doubling Times

Alkalithermophiles are an exciting subset of extremophilic organisms and represent extremophiles that are adapted to two extreme conditions, i.e. to a combination of alkaline and thermobiotic growth conditions. Among the anaerobic alkalithermophiles are representatives of both Bacteria and Archaea within a wide variety of physiological types and systematic groups, although a great majority belongs to the Firmicutes. Alkaliphiles have been isolated from a variety of niches including mesobiotic and neutrophilic soils and sediments. Interestingly anaerobic isolates from mesobiotic and neutrophilic niches exhibit shorter doubling times than isolates from thermobiotic niches; some anaerobic alkalithermophiles exhibit extremely fast growth rates, i.e. doubling times as short as 10 min. Their adaptation to both high pH and high temperature draws our attention not only because they are potential sources of industrially valuable enzymes but also because of their adaptive mechanisms to external environmental parameters. They could thus function as model organisms for extraterrestrial life in some environments and for theories on the origin of life. Alkalithermophiles, as far we know, do not represent the most thermophilic nor the most alkaliphilic of micro-organisms but represent the most alkaliphilic ones among the thermophiles and vice versa. We believe that the presently known species are only the tip of the iceberg and therefore that they do not represent the true boundaries under which life can thrive in respect to high temperature in alkaline environments.

STRUCTURE AND DYNAMICS OF ENVIRONMENTAL PARAMETERS OF HUMAN INTESTINAL MICROBIOME IN DIFFERENT CLIMATIC AND ECOLOGICAL ZONES OF ST. PETERSBURG

2020 ◽  
pp. 31-36
Author(s):  
Bugero N.V. ◽  
Ilyina N.A. ◽  
Aleksandrova S.M.
Keyword(s):  
Environmental Parameters ◽  
Intestinal Microbiome ◽  
Ecological Niches ◽  
Horizontal Structure ◽  
Ecological Zones ◽  
Qualitative And Quantitative ◽  
Symbiotic Relationships ◽  
Structure And Dynamics ◽  
Quantitative Changes ◽  
Micro Organisms

In order to understand the structure and dynamics of symbiotic relationships of human intestinal biotope micro-organisms, taxonomic constancy indices, the degree of contagion of the biocenosis under study and floristic significance were investigated, which made it possible to detect qualitative and quantitative changes in the microecology of the biotope being studied in persons living in different ecologically heterogeneous territories of Saint Petersburg. The contagiosity index estimated the distribution of species in space. Persons living in the ecologically disadvantaged Kirov district of the city have been found to show a reliable increase in this indicator for the obligate microflora: bifido and lacto bacteria, intestinal columns and bacteroids, compared to the resort district, which is considered a relatively favourable area for residence. On the contrary, there has been a reliable decrease in this indicator in the group of opportunistic micro-organisms (fungi of the genus Candida, staphylococcus, clostridium, etc.), resulting in the liberation of ecological niches successfully occupied by transient flora. This ratio reveals an imbalance of participation in the horizontal structure of the intestine ecosystem of the main symbiotes and representatives of the transient flora. To analyse the structure of symbiotic relationships, the constancy indices that form the microflora of the individuals of the groups studied were investigated. The analysis of the data obtained suggested that the dominant species in both groups were optional-anaerobic bifido and lactobacteria and oblique-anaerobic bacteroids. It should be noted, however, that in the residents of the dysfunctional Kirovsky district, against the background of the reduced constancy of the normal flora, opportunistic micro-organisms have entered. The floral significance index was also declining in the obligate flora of this group and increased for opportunistic species. Thus, the study of the environmental characteristics of the intestinal biotope using different ecological parameters for persons living in different technogenic load regions of St. Petersburg has shown that in the Kirov district with an unfavourable environmental situation there are compensated qualitative and quantitative changes in the intestinal microbiocenosis, resulting in a change in the hierarchy in the overall structure of micro-organisms.

scholarly journals Autophagy-Related Protein ATG8 Has a Noncanonical Function for Apicoplast Inheritance in Toxoplasma gondii

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Maude F. Lévêque ◽  
Laurence Berry ◽  
Michael J. Cipriano ◽  
Hoa-Mai Nguyen ◽  
Boris Striepen ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Growth Conditions ◽  
Model Organisms ◽  
Secondary Endosymbiosis ◽  
Related Protein ◽  
Content Type ◽  
Superresolution Microscopy ◽  
Animal Pathogens ◽  
Cellular Components ◽  
Catabolic Process

ABSTRACT Autophagy is a catabolic process widely conserved among eukaryotes that permits the rapid degradation of unwanted proteins and organelles through the lysosomal pathway. This mechanism involves the formation of a double-membrane structure called the autophagosome that sequesters cellular components to be degraded. To orchestrate this process, yeasts and animals rely on a conserved set of autophagy-related proteins (ATGs). Key among these factors is ATG8, a cytoplasmic protein that is recruited to nascent autophagosomal membranes upon the induction of autophagy. Toxoplasma gondii is a potentially harmful human pathogen in which only a subset of ATGs appears to be present. Although this eukaryotic parasite seems able to generate autophagosomes upon stresses such as nutrient starvation, the full functionality and biological relevance of a canonical autophagy pathway are as yet unclear. Intriguingly, in T. gondii, ATG8 localizes to the apicoplast under normal intracellular growth conditions. The apicoplast is a nonphotosynthetic plastid enclosed by four membranes resulting from a secondary endosymbiosis. Using superresolution microscopy and biochemical techniques, we show that TgATG8 localizes to the outermost membrane of this organelle. We investigated the unusual function of TgATG8 at the apicoplast by generating a conditional knockdown mutant. Depletion of TgATG8 led to rapid loss of the organelle and subsequent intracellular replication defects, indicating that the protein is essential for maintaining apicoplast homeostasis and thus for survival of the tachyzoite stage. More precisely, loss of TgATG8 led to abnormal segregation of the apicoplast into the progeny because of a loss of physical interactions of the organelle with the centrosomes. IMPORTANCE By definition, autophagy is a catabolic process that leads to the digestion and recycling of eukaryotic cellular components. The molecular machinery of autophagy was identified mainly in model organisms such as yeasts but remains poorly characterized in phylogenetically distant apicomplexan parasites. We have uncovered an unusual function for autophagy-related protein ATG8 in Toxoplasma gondii: TgATG8 is crucial for normal replication of the parasite inside its host cell. Seemingly unrelated to the catabolic autophagy process, TgATG8 associates with the outer membrane of the nonphotosynthetic plastid harbored by the parasite called the apicoplast, and there it plays an important role in the centrosome-driven inheritance of the organelle during cell division. This not only reveals an unexpected function for an autophagy-related protein but also sheds new light on the division process of an organelle that is vital to a group of important human and animal pathogens.

scholarly journals Исследование нелегированных нанокристаллических алмазных пленок, выращенных из газовой фазы в плазме СВЧ разряда

2021 ◽  
Vol 55 (1) ◽  
pp. 49
Author(s):  
А.Л. Вихарев ◽  
С.А. Богданов ◽  
Н.М. Овечкин ◽  
О.А. Иванов ◽  
Д.Б. Радищев ◽  
...  
Keyword(s):  
High Temperature ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Inert Gas ◽  
Dielectric Films ◽  
High Temperature Annealing ◽  
Structural And Electrical Properties ◽  
Methane Mixture

Undoped nanocrystalline diamond (NCD) films less than 1 μm thick grown on Si (100) silicon by microwave plasma-assisted chemical vapor deposition at a frequency of 2.45 GHz are studied. To obtain diamond dielectric films with maximum resistivity the deposition of films in three gas mixtures is investigated: hydrogen-methane mixture, hydrogen-methane mixture with the addition of oxygen and hydrogen-methane mixture with the addition of an inert gas. A relationship has been established between the growth conditions, structural and electrical properties of NCD films. It is shown that for the use of NCD films as effective dielectrics preliminary high-temperature annealing of the films is required, for example, in vacuum at a temperature of 600°C for one hour.

scholarly journals Introduction. Antarctic ecology: from genes to ecosystems. Part 2. Evolution, diversity and functional ecology

2007 ◽  
Vol 362 (1488) ◽  
pp. 2187-2189 ◽  
Author(s):  
Alex D Rogers ◽  
Eugene J Murphy ◽  
Nadine M Johnston ◽  
Andrew Clarke
Keyword(s):  
Climate Change ◽  
Life Histories ◽  
Natural Populations ◽  
Environmental Parameters ◽  
Functional Ecology ◽  
Antarctic Species ◽  
Trade Offs ◽  
Genes To Ecosystems ◽  
Micro Organisms ◽  
The Antarctic

The Antarctic biota has evolved over the last 100 million years in increasingly isolated and cold conditions. As a result, Antarctic species, from micro-organisms to vertebrates, have adapted to life at extremely low temperatures, including changes in the genome, physiology and ecological traits such as life history. Coupled with cycles of glaciation that have promoted speciation in the Antarctic, this has led to a unique biota in terms of biogeography, patterns of species distribution and endemism. Specialization in the Antarctic biota has led to trade-offs in many ecologically important functions and Antarctic species may have a limited capacity to adapt to present climate change. These include the direct effects of changes in environmental parameters and indirect effects of increased competition and predation resulting from altered life histories of Antarctic species and the impacts of invasive species. Ultimately, climate change may alter the responses of Antarctic ecosystems to harvesting from humans. The unique adaptations of Antarctic species mean that they provide unique models of molecular evolution in natural populations. The simplicity of Antarctic communities, especially from terrestrial systems, makes them ideal to investigate the ecological implications of climate change, which are difficult to identify in more complex systems.

Calditerricola satsumensis gen. nov., sp. nov. and Calditerricola yamamurae sp. nov., extreme thermophiles isolated from a high-temperature compost

2011 ◽  
Vol 61 (3) ◽  
pp. 631-636 ◽  
Author(s):  
Toshiyuki Moriya ◽  
Tomohisa Hikota ◽  
Isao Yumoto ◽  
Takashi Ito ◽  
Yusuke Terui ◽  
...  
Keyword(s):  
High Temperature ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Strain ◽  
Sequence Similarity ◽  
Synthetic Medium ◽  
Rrna Gene ◽  
Isoleucine Leucine ◽  
Micro Organisms ◽  
The 16S Rrna Gene

Two novel thermophilic micro-organisms, designated YMO81T and YMO722T, were isolated from a high-temperature compost (internal temperature >95 °C). The isolates were able to grow at 80 °C in a nutrient broth and in a synthetic medium. Cells were aerobic, Gram-negative rods (0.3×4.0 μm). Spore formation was not observed. Strain YMO81T grew at 83 °C and pH 6.9–8.9 and grew optimally at 78 °C and pH 7.5 with 2 % NaCl. For growth in a synthetic minimal medium at 70 °C, the vitamins biotin, folic acid and thiamine and the amino acids glutamine and methionine were essential for growth of both strains; at 80 °C, strain YMO81T also required histidine, isoleucine, leucine, lysine, phenylalanine, serine, tryptophan and valine. Cellular fatty acids of the isolates comprised mainly iso-C17 : 0 and anteiso-C17 : 0. The DNA G+C contents of strains YMO81T and YMO722T were 70 and 64 mol%, respectively. When the 16S rRNA gene sequences of the isolates were compared with those of other bacteria, highest similarity was observed with Planifilum yunnanense LA5T (90 % 16S rRNA gene sequence similarity). DNA–DNA relatedness between strain YMO722T and strain YMO81T was 55 %. N 4-Aminopropylspermine was identified as a major polyamine, which suggested that the isolates were distinct from other related taxa. On the basis of phylogenetic, phenotypic and chemotaxonomic analyses, we propose a new genus, Calditerricola gen. nov., and two novel species, the type species Calditerricola satsumensis sp. nov., with type strain YMO81T (=ATCC BAA-1462T =JCM 14719T =DSM 45223T), and Calditerricola yamamurae sp. nov., with type strain YMO722T (=ATCC BAA-1461T =JCM 14720T =DSM 45224T).

scholarly journals Macrodefects in Cubic Silicon Carbide Crystals

2010 ◽  
Vol 645-648 ◽  
pp. 375-378 ◽  
Author(s):  
Valdas Jokubavicius ◽  
Justinas Palisaitis ◽  
Remigijus Vasiliauskas ◽  
Rositza Yakimova ◽  
Mikael Syväjärvi
Keyword(s):  
Growth Rate ◽  
Silicon Carbide ◽  
Crystal Growth ◽  
High Temperature ◽  
Temperature Gradient ◽  
Early Stage ◽  
Growth Conditions ◽  
Temperature Ramp ◽  
Cubic Silicon Carbide ◽  
Sublimation Growth

Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 μm/h with the thickness of the crystals from 190 to 230 μm, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

ChemInform Abstract: Growth Conditions, Electrical Resistivity, Microhardness, and Thermal Properties of Nb5Sn2Ga Single Crystals Synthesized from High-Temperature Tin Solutions.

ChemInform ◽  
2010 ◽  
Vol 30 (11) ◽  
pp. no-no
Author(s):  
Shigeru Okada ◽  
Kunio Kudou ◽  
Toetsu Shishido ◽  
Iwami Higashi ◽  
Hiroyuki Horiuchi ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Thermal Properties ◽  
High Temperature ◽  
Single Crystals ◽  
Growth Conditions

Defect Assessment Procedure for Low to High Temperature Range

2003 ◽  
Author(s):  
Bilal Dogan ◽  
Robert Ainsworth
Keyword(s):  
High Temperature ◽  
Growth Conditions ◽  
Life Assessment ◽  
Assessment Procedure ◽  
High Temperature Range ◽  
Temperature Range ◽  
Defect Assessment ◽  
Creep Fatigue ◽  
Recent Developments ◽  
Assessment Procedures

There are many similarities between available procedures used for defect assessment. They have been developed as a result of experience gained from material-specific programs and have often been verified using the same data. One recently updated document covering life assessment procedures under creep and creep/fatigue crack growth conditions is BS 7910. This document takes into account some of the most recent developments in the subject, including some from the British Energy R5 Procedure. Future developments in defect assessment procedures will follow the route of simplified and unified codes covering defect behaviour in the low to high temperature range. In this paper, the relevance of the insignificant creep curves in RCC-MR for defect free structures and the creep exemption criteria in BS7910 are examined. Then, an overview is given of some European developments in defect assessment methods for Fitness-for-Service assessment, based on recent and current projects such as the EC thematic network FITNET.

Attitudes towards the scientific search for extraterrestrial life among Swedish high school and university students

2018 ◽  
Vol 18 (3) ◽  
pp. 280-288 ◽  
Author(s):  
Erik Persson ◽  
Klara Anna Capova ◽  
Yuan Li
Keyword(s):  
High School ◽  
High School Students ◽  
University Students ◽  
Great Majority ◽  
School Students ◽  
Extraterrestrial Life ◽  
Fields Of Study

AbstractThe aim of this study is to increase our understanding of the attitudes towards the scientific search for extraterrestrial life among high school and university students in Sweden. The most important results of the analysis are that: (a) the great majority of students believe that extraterrestrial life exists; (b) most students regard searching for extraterrestrial life to be quite important or very important; (c) very few students think that we should actively avoid searching for extraterrestrial life; (d) the most common motive for assigning a high priority to search for extraterrestrial life is that it is interesting, the most common motive for assigning a low priority is that such knowledge would not be practically useful, or that the money would be better spent elsewhere; (e) most students do not think they are very well informed regarding the search for extraterrestrial life. A higher percentage of the students who judge themselves to be well informed also believe that extraterrestrial life exists. We have also found some differences between subgroups (men/women, high school students/university students and different fields of study), but the differences are with few exceptions small in comparison with the overall trends, and they mostly differ in degree rather than direction.

scholarly journals Regulation of Bioluminescence in Photobacterium leiognathi Strain KNH6

2015 ◽  
Vol 197 (23) ◽  
pp. 3676-3685 ◽  
Author(s):  
Anne K. Dunn ◽  
Bethany A. Rader ◽  
Eric V. Stabb ◽  
Mark J. Mandel
Keyword(s):  
Tca Cycle ◽  
Growth Conditions ◽  
Model Organisms ◽  
Content Type ◽  
Dna And Rna ◽  
Apply Genetic ◽  
Light Production ◽  
Photobacterium Leiognathi ◽  
Pheromone Signaling ◽  
Luminous Bacteria

ABSTRACTBacterial bioluminescence is taxonomically restricted to certain proteobacteria, many of which belong to theVibrionaceae. In the most well-studied cases, pheromone signaling plays a key role in regulation of light production. However, previous reports have indicated that certainPhotobacteriumstrains do not use this regulatory method for controlling luminescence. In this study, we combined genome sequencing with genetic approaches to characterize the regulation of luminescence inPhotobacterium leiognathistrain KNH6, an extremely bright isolate. Using transposon mutagenesis and screening for decreased luminescence, we identified insertions in genes encoding components necessary for the luciferase reaction (lux,lum, andriboperons) as well as in nine other loci. These additional loci encode gene products predicted to be involved in the tricarboxylic acid (TCA) cycle, DNA and RNA metabolism, transcriptional regulation, and the synthesis of cytochromec, peptidoglycan, and fatty acids. The mutagenesis screen did not identify any mutants with disruptions of predicted pheromone-related loci. Using targeted gene insertional disruptions, we demonstrate that under the growth conditions tested, luminescence levels do not appear to be controlled through canonical pheromone signaling systems in this strain.IMPORTANCEDespite the long-standing interest in luminous bacteria, outside a few model organisms, little is known about the regulation and function of luminescence. Light-producing marine bacteria are widely distributed and have diverse lifestyles, suggesting that the control and significance of luminescence may be similarly diverse. In this study, we apply genetic tools to the study of regulation of light production in the extremely bright isolatePhotobacterium leiognathiKNH6. Our results suggest an unusual lack of canonical pheromone-mediated control of luminescence and contribute to a better understanding of alternative strategies for regulation of a key bacterial behavior. These experiments lay the groundwork for further study of the regulation and role of bioluminescence inP. leiognathi.

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