Search inside the book. Text Bibliography Notes Author s. Cet auteur remarque for Sur les 50 qui se tr Zoom in Original jpeg, 1,2M. La plus manifeste c List of illustrations Caption Fig. Freemium Recommend to your library for acquisition. The postal address of the institution is: Mythes et limites [online]. Available on the Internet: Your e-mail has be sent. Catalogue Author s Publishers Selections Excerpts. The analysis of the datum is based on the results of a questionnaire focusing on the socio-demographic profile of a group of students from fourth and fifth year attending two multiethnic High Schools of the North-Crown of Montreal as well as on the interviews with fifteen of those students who are from a haitian background.
There were also interviews with some parents, a member of a community organism, some staff members of some schools as well as some Haitian-Quebecer professionals and scientists, in order to have a critical viewpoint upon the different positions expressed by the fifteen students. The Bronfenbrenner's ecosystemic model , has been used as scope of reference allowing to draw the prominent aspects from the attitudes toward science in the students, from haitian background.
The synthesis of ideas expressed by different interviewee reveals the existence of a environment not much enhancing the value of sciences around of students, from Haitian background. The socio-economic conditions, the familial practices, the ethnocultural status as well as some individual representations of sciences contribute to create and maintain some attitudes very little committed to sciences in those students.
The study shows how much it is urgent to demystify the sciences by breaking with some stereotypes that prevent some categories of students from acceding to sciences. It also commands to politicians, concerning education, to be more open to ethnocultural differences and to explore some dynamic ways in. DES Collaboration; and others. The Science Verification data span approximately sq. The Year 1 data span approximately sq. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster.
Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly , cutouts, we present candidate strong lens systems, of which are identified for the first time. We provide the R. Pollution is a man-made phenomenon. Some pollutants which discharged directly to the environment could create serious pollution problems.
Untreated wastewater will cause contamination and even pollution on the water body. The higher the BOD concentration, the greater the organic matter would be. The purpose of this study was to predict the value of BOD contained in wastewater. Mathematical modeling methods were chosen in this study to depict and predict the BOD values contained in facultative wastewater stabilization ponds. Measurements of sampling data were carried out to validate the model.
The results of this study indicated that a mathematical approach can be applied to predict the BOD contained in the facultative wastewater stabilization ponds. Heritable microbial symbionts can have important effects on many aspects of their hosts' biology.
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Acquisition of a novel symbiont strain can provide fitness benefits to the host, with significant ecological and evolutionary consequences. We measured barriers to horizontal transmission by artificially transferring facultative symbionts from the grain aphid, Sitobion avenae, and five other aphid species into two clonal genotypes of S. We found the symbiont Hamiltonella defensa establishes infections more easily following a transfer from the same host species and that such infections are more stable. Infection success was also higher when the introduced symbiont strain was more closely related to the strain that was originally present in the host but which had previously been removed.
There were no differences among successfully established symbiont strains in their effect on aphid fecundity. Hamiltonella defensa did not confer protection against parasitoids in our S. However, strains of the symbiont Regiella insecticola originating from two host species protected grain aphids against the pathogenic fungus Pandora neoaphidis.
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This study helps describe the extent to which facultative symbionts can act as a pool of adaptations that can be sampled by their eukaryote hosts. Absence of genome reduction in diverse, facultative endohyphal bacteria. Fungi interact closely with bacteria, both on the surfaces of the hyphae and within their living tissues i.
These EHB can be obligate or facultative symbionts and can mediate diverse phenotypic traits in their hosts. Although EHB have been observed in many lineages of fungi, it remains unclear how widespread and general these associations are, and whether there are unifying ecological and genomic features can be found across EHB strains as a whole. We cultured 11 bacterial strains after they emerged from the hyphae of diverse Ascomycota that were isolated as foliar endophytes of cupressaceous trees, and generated nearly complete genome sequences for all. Unlike the genomes of largely obligate EHB, the genomes of these facultative EHB resembled those of closely related strains isolated from environmental sources.
Although all analysed genomes encoded structures that could be used to interact with eukaryotic hosts, pathways previously implicated in maintenance and establishment of EHB symbiosis were not universally present across all strains. Independent isolation of two nearly identical pairs of strains from different classes of fungi, coupled with recent experimental evidence, suggests horizontal transfer of EHB across endophytic hosts. Given the potential for EHB to influence fungal phenotypes, these genomes could shed light on the mechanisms of plant growth promotion or stress mitigation by fungal endophytes during the symbiotic phase, as well as degradation of plant material during the saprotrophic phase.
As such, these findings contribute to the illumination of a new dimension of functional biodiversity in fungi. Facultative methanotrophs are a group of phylogenetically diverse microorganisms characterized by their ability to use methane and some other compounds containing C-C bond as their sole source of carbon and energy. Recently, which belong to the facultative methanotrophs in the genera Methylocella, Methylocapsa and Methylocystis, which belong to the Alphaproteobacteria, have been reported that can grow on larger organic acids or ethanol for some species, as well as methane.
In this paper, the research history of facultative methanotrophs was summarized systematically, some other facultative methane-oxidizing microorganisms were introduced, the metabolic mechanisms of utilizing multi-carbon compounds by facultative methanotrophs were analyzed, and the current problems and the future engineering applications were discussed. Elle est traitA c e A partir de sources nouvelles, et avec rigueur. On y trouvera en particulier des informations sur un mathA c m. These were used to investigate the distribution of Methylocella spp.
It was revealed that Methylocella species are widely distributed in nature and not restricted to acidic environments. Fermentation of polysaccharides by Klebsiella and other facultative bacilli. Fermentations of 10 polysaccharides by species of the family Enterobacteriaceae were examined.
Algin, guar, karaya, xanthan, and xylan were not fermented by any of the strains tested. Most of the activity was found in the tribe Klebsielleae. With one exception, Serratia strains were negative on all polysaccharides. These results, along with other evidence, indicate that i the genus Klebsiella is biochemically the most versatile genus of the tribe, ii because of its distinct characteristics, K. Fermentation of polysaccharides by Klebsielleae and other facultative bacilli.
Aphid facultative symbionts reduce survival of the predatory lady beetle Hippodamia convergens. Background Non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. For example, two facultative bacterial symbionts of the pea aphid Acyrthosiphon pisum , Serratia symbiotica and Hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp.
Previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. We tested whether feeding on aphids harboring different facultative symbionts affected the fitness of an aphid predator, the lady beetle Hippodamia convergens.
Results While these aphid faculative symbionts did not deter lady beetle feeding, they did decrease survival of lady beetle larvae. Lady beetle larvae fed a diet of aphids with facultative symbionts had significantly reduced survival from egg hatching to pupation and therefore had reduced survival to adult emergence.
Additionally, lady beetle adults fed aphids with facultative symbionts were significantly heavier than those fed facultative symbiont-free aphids, though development time was not significantly different. Conclusions Aphids reproduce clonally and are often found in large groups. Thus, aphid symbionts, by reducing the fitness of the aphid predator H. These findings highlight the often far-reaching effects that symbionts can have in ecological systems. Union mondiale pour la conservation de la nature et des ressources Geben Sie's zu, wir alle fragen gerne mal: Sie haken nach, bis es als Antwort nur noch gibt: Aus purer Energie werden Teilchen erzeugt.
Materieteilchen bekommen Geschwister aus Antimaterie. Das ist die Welt der Teilchenphysik. Wer das alles auch so spannend findet wie die Teilchenphysiker selbst, ist herzlich eingeladen, dieses Buch zu lesen. Wer glaubt, dass man ohne ein Studium in der Teilchenphysik nichts versteht, der auch. Quantenfeldtheorien, Teilchenbeschleuniger, Higgs-Mechanismus und Co werden hier Conformist social learning can have a pronounced impact on the cultural evolution of human societies, and it can shape both the genetic and cultural evolution of human social behavior more broadly. Conformist social learning is beneficial when the social learner and the demonstrators from whom she learns are similar in the sense that the same behavior is optimal for both.
Otherwise, the social learner's optimum is likely to be rare among demonstrators, and conformity is costly. The trade-off between these two situations has figured prominently in the longstanding debate about the evolution of conformity, but the importance of the trade-off can depend critically on the flexibility of one's social learning strategy. We developed a gene-culture coevolutionary model that allows cognition to encode and process information about the similarity between naive learners and experienced demonstrators.
Facultative social learning strategies that condition on perceived similarity evolve under certain circumstances.
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When this happens, facultative adjustments are often asymmetric. Asymmetric adjustments mean that the tendency to follow the majority when learners perceive demonstrators as similar is stronger than the tendency to follow the minority when learners perceive demonstrators as different. In an associated incentivized experiment, we found that social learners adjusted how they used social information based on perceived similarity, but adjustments were symmetric.
The symmetry of adjustments completely eliminated the commonly assumed trade-off between cases in which learners and demonstrators share an optimum versus cases in which they do not. In a second experiment that maximized the potential for social learners to follow their preferred strategies, a few social learners exhibited an inclination to follow the majority. Most, however, did not respond systematically to social information. Additionally, in the complete absence of information about their similarity to. Full Text Available Conformist social learning can have a pronounced impact on the cultural evolution of human societies, and it can shape both the genetic and cultural evolution of human social behavior more broadly.
Additionally, in the complete absence of information about their. Facultative methanotrophs are abundant at terrestrial natural gas seeps. Natural gas contains methane and the gaseous alkanes ethane, propane and butane, which collectively influence atmospheric chemistry and cause global warming. Methane-oxidising bacteria, methanotrophs, are crucial in mitigating emissions of methane as they oxidise most of the methane produced in soils and the subsurface before it reaches the atmosphere.
Methanotrophs are usually obligate, i. Bacteria that grow on the other gaseous alkanes in natural gas such as propane have also been characterised, but they do not grow on methane. Recently, it was shown that the facultative methanotroph Methylocella silvestris grew on ethane and propane, other components of natural gas, in addition to methane. Therefore, we hypothesised that Methylocella may be prevalent at natural gas seeps and might play a major role in consuming all components of this potent greenhouse gas mixture before it is released to the atmosphere.
Environments known to be exposed to biogenic methane emissions or thermogenic natural gas seeps were surveyed for methanotrophs. New Methylocella-specific molecular tools targeting mmoX encoding the soluble methane monooxygenase by PCR and Illumina amplicon sequencing were designed and used to investigate various sites. Functional gene-based assays confirmed that Methylocella were present in all of the natural gas seep sites tested here. This might be due to its ability to use methane and other short chain alkane components of natural gas.
We also observed the abundance of Methylocella in other environments exposed to biogenic methane, suggesting that Methylocella has been overlooked in the past as previous ecological studies of methanotrophs often used pmoA encoding the alpha subunit of particulate methane monooxygenase as a marker gene. New biomolecular tools designed in.
En la literatura contable en lenguas no latinas no es tan fuerte el reconocimento de la influencia de Mattheu de la Porte, aunque se reconoce, por ejemplo, en Alemania por Dieter Schneider Las apreciaciones de autores acreditados. A primordial and reversible TCA cycle in a facultatively chemolithoautotrophic thermophile. Inorganic carbon fixation is essential to sustain life on Earth, and the reductive tricarboxylic acid rTCA cycle is one of the most ancient carbon fixation metabolisms.
A combination of genomic, enzymatic, and metabolomic analyses of a deeply branching chemolithotrophic Thermosulfidibacter takaii ABI70S6 T revealed a previously unknown reversible TCA cycle whose direction was controlled by the available carbon source s. Under a chemolithoautotrophic condition, a rTCA cycle occurred with the reverse reaction of citrate synthase CS and not with the adenosine 5'-triphosphate-dependent citrate cleavage reactions that had been regarded as essential for the conventional rTCA cycle.
Phylometabolic evaluation suggests that the TCA cycle with reversible CS may represent an ancestral mode of the rTCA cycle and raises the possibility of a facultatively chemolithomixotrophic origin of life. No claim to original U. Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses.
A total of specimens collected from purulent skin lesions of household cats was examined bacteriologically. Ninety seven isolates obtained from 74 specimens Of these, 11 specimens 9. In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F. Pasteurella multocida was the facultative anaerobe which was most frequently detected.
Rumex acetosa Y chromosomes: Condensed Y chromosomes in Rumex acetosa L. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea Sw.
It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive.
Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA. Males and females of all life stages were aligned to this transcriptome for analysis of gene expression profiles throughout development. Gene Ontology analysis indicates that stage-specific genes are involved in ion transport, cell-cell signaling, and metabolism. A number of distinct biological processes are upregulated in each life stage, and transitions between life stages involve shifts in dominant functional processes, including shifts from transcriptional regulation in embryos to metabolism in larvae, and increased lipid metabolism in adults.
We expect that this transcriptome will provide a useful resource for future analyses to better understand the molecular basis of the evolution of eusociality and, more generally, phenotypic plasticity. Indirect evolution of social fitness inequalities and facultative social exploitation. Microbial genotypes with similarly high proficiency at a cooperative behaviour in genetically pure groups often exhibit fitness inequalities caused by social interaction in mixed groups.
Winning competitors in this scenario have been referred to as 'cheaters' in some studies. Such interaction-specific fitness inequalities, as well as social exploitation in which interaction between genotypes increases absolute fitness , might evolve due to selection for competitiveness at the focal behaviour or might arise non-adaptively due to pleiotropy, hitchhiking or genetic drift. The bacterium Myxococcus xanthus sporulates during cooperative development of multicellular fruiting bodies.
Fitness inequalities between evolved genotypes were not caused by divergence in developmental speed, as faster-developing strains were not over-represented among competition winners. In competitions between ancestors and several evolved strains, all evolved genotypes produced more spores than the ancestors, including losers of evolved-versus-evolved competitions, indicating that adaptation in non-developmental contexts pleiotropically increased competitiveness for spore production.
Overall, our results suggest that fitness inequalities caused by social interaction during cooperative processes may often evolve non-adaptively in natural populations. Facultative or dedicated progenitors? The adult pancreas is only capable of limited regeneration. Unlike highly regenerative tissues such as the skin, intestinal crypts and hematopoietic system, no dedicated adult stem cells or stem cell niche have so far been identified within the adult pancreas.
We present an overview of regenerative responses noted within the different pancreatic lineages, following injury. We also highlight the intrinsic plasticity of the adult pancreas that allows for inter-conversion of fully differentiated pancreatic lineages through manipulation of few genes or growth factors. Published by Elsevier B.
LEGS background
Methanotrophs are a group of phylogenetically diverse microorganisms characterized by their ability to utilize methane as their sole source of carbon and energy. Early studies suggested that growth on methane could be stimulated with the addition of some small organic acids, but initial efforts to find facultative methanotrophs, i. Recently, however, facultative methanotrophs in the genera Methylocella, Methylocapsa, and Methylocystis have been reported that can grow on acetate, as well as on larger organic acids or ethanol for some species.
All identified facultative methanotrophs group within the Alphaproteobacteria and utilize the serine cycle for carbon assimilation from formaldehyde. It is possible that facultative methanotrophs are able to convert acetate into intermediates of the serine cycle e. In this review, we summarize the history of facultative methanotrophy, describe scenarios for the basis of facultative methanotrophy, and pose several topics for future research in this area.
Published by Blackwell Publishing Ltd. Facultative crassulacean acid metabolism CAM plants: Facultative crassulacean acid metabolism CAM describes the optional use of CAM photosynthesis, typically under conditions of drought stress, in plants that otherwise employ C3 or C4 photosynthesis. In its cleanest form, the upregulation of CAM is fully reversible upon removal of stress. Using mainly measurements of 24h CO2 exchange, defining features of facultative CAM are highlighted in five terrestrial species, Clusia pratensis, Calandrinia polyandra, Mesembryanthemum crystallinum, Portulaca oleracea and Talinum triangulare.
For these, we provide detailed chronologies of the shifts between photosynthetic modes and comment on their usefulness as experimental systems. Photosynthetic flexibility is also reviewed in an aquatic CAM plant, Isoetes howellii. Facultative CAM species will be of even greater relevance now that new sequencing technologies facilitate the mapping of genomes and tracking of the expression patterns of multiple genes. These technologies and facultative CAM systems, when joined, are expected to contribute in a major way towards our goal of understanding the essence of CAM.
For permissions, please email: Isolation of thermotolerant, halotolerant, facultative biosurfactant-producing bacteria. Several facultative bacterial strains tolerant to high temperature and salinity were isolated from the oil reservoir brines of an Iranian oil field Masjed-I Soleyman. Tolerances to NaCl levels decreased as the growth temperatures were increased.
Surfactant production ability was detected in some of these isolates. The use of biosurfactant is considered as an effective mechanism in microbial-enhanced oil recovery processes detected in some of these isolates. These isolates exhibited morphological and physiological characteristics of the Bacillus genus. The partial sequencing of the 16S ribosomal deoxyribonucleic acid gene of the selected isolates was assigned them to Bacillus subtilis group. The biosurfactant produced by these isolates caused a substantial decrease in the surface tension of the culture media to By the use of thin-layer chromatography technique, the presence of the three compounds was detected in the tested biosurfactant.
Infrared spectroscopy and 1 H nuclear magnetic resonance analysis were used, and the partial structural characterization of the biosurfactant mixture of the three compounds was found to be lipopeptidic in nature. The possibility of use of the selected bacterial strains reported, in the present study, in different sectors of the petroleum industry has been addressed. Obligatory and facultative brain regions for voice-identity recognition. La mission de ce groupement est: La physique des infinis. Quelles sont les particules manquantes?
Faut-il revoir les lois fondamentales? Comment parler de Super Big Science aux citoye L'interdisciplinarite en sciences sociales pour l'etude du contact des langues Interdisciplinarity in Social Sciences of the Study of the Relationships of Languages. Papers given at an international conference applying the social sciences to the study of the relationships of languages include the following: Differntiation genetique des populations geographiques de Cameroon Journal of Agricultural Science Vol.
In Canada, a number of university programs in business administration have imbedded major reforms, following requests from accreditation bodies such as the Association to Advance Collegiate Schools of Business AACSB. Consequently, more and more learning assessment methods are used. However, the introduction of these methods in curricula could lead to bias to the results of learning assessment.
The author, in a previous article has analysed the vocabulary of hydrauhcs. This paper is concerned with the study of the hidrologic as well as the auxiliay sciences terms which appear in the eighth book of De architectura of Vitrube. He studies the words used to designate the soil texture, its chemical constituents, and especially these relative to the hidrology, in order to enhance the global idea the ancient world had about natural phenomena.
This paper discusses the connectivity of constitutional law doctrine on findings of governance research and behavioral science. Fundamental questions how to integrate "soft" instruments like "framing" and "nudging" in a constitutional law doctrine will be considered. The image of man in the constitutional order, as presupposed in the German and in the Austrian constitution, will be illuminated. For a doctrine of state communication accuracy, objectivity and due restraint are key postulates. Draft genome of an Aerophobetes bacterium reveals a facultative lifestyle in deep-sea anaerobic sediments.
Aerophobetes or CD12 is a recently defined bacterial phylum, of which the metabolic processes and ecological importance remain unclear. In the present study, we obtained the draft genome of an Aerophobetes bacterium TCS1 from saline sediment near the Thuwal cold seep in the Red Sea using a genome binning method. Phylogenetic relationships showed affinity between Aerophobetes TCS1 and some thermophilic bacterial phyla. The genome of TCS1 at least 1. The identification of cross-membrane sugar transporter genes further indicates its potential ability to consume carbohydrates preserved in the sediment under the microbial mat.
Aerophobetes bacterium TCS1 therefore probably carried out saccharolytic and fermentative metabolism. The genes responsible for autotrophic synthesis of acetyl-CoA via the Wood—Ljungdahl pathway were also found in the genome. Phylogenetic study of the essential genes for the Wood—Ljungdahl pathway implied relative independence of Aerophobetes bacterium from the known acetogens and methanogens. Compared with genomes of acetogenic bacteria, Aerophobetes bacterium TCS1 genome lacks the genes involved in nitrogen metabolism, sulfur metabolism, signal transduction and cell motility.
The metabolic activities of TCS1 might depend on geochemical conditions such as supplies of CO2, hydrogen and sugars, and therefore the TCS1 might be a facultative bacterium in anaerobic saline sediments near cold seeps. Theoretical approach and meta-analysis of the internet audiences. Cameroon Journal of Agricultural Science. Journal Camerounais des Sciences Agricoles The Cameroon Journal of Agricultural Science publishes new information on all aspects of agricultural science — agronomy, breeding, crop protection, economics, rural sociology, forestry and animal science , health and production We find here the progress report for the two years and for institute of nuclear sciences at Grenoble.
In the field of quarks and leptons, three teams are invested in CERN programmes: I; the neutrino team has achieved the building of the detector in the M. In the theme Hadrons physics we have G. Physicists are implied in the project E. The study of superdeformed states go on with E. New techniques have been used near the programme S.
The team of hybrid reactors have shown that it was possible to amplify energy by a sub critical accelerator-reactor hybrid system, experience initiated by C. Dictionnaire des risques psychosociaux. C'est tout l'enjeu de ce dictionnaire, pionnier en son genre. Brevibacterium siliguriense sp nov. A Gram-positive-staining, rod-shaped, facultatively oligotrophic bacterial strain, designated MB18 T , was isolated from a water sample collected from the River Mahananda at Siliguri 26 degrees 44' On the basis of 16S rRNA gene sequence.
Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik Northwest Territories, Canada.
Full Text Available Aim: To detect for the presence of sulphate-reducing bacteria SRB and evaluate the possible association between SRB and cultivable facultative bacterial of oral sites with different periodontal conditions. The study was carried out on 9 samples from different oral sites in 8 patients two samples were collected from the same patient.
Material was collected using modified Postgate E culture medium, indicated for the growth and isolation of SRB. In addition, a reducing solution for anaerobic bacteria was used as a transport solution for facultative bacteria and identified by polymerase chain reaction amplification PCR and sequencing of the 16S rRNA gene. SRB was found in 3 patient samples: In the final patient, the cultivable facultative species Lactobacillus casei was identified.
Other facultative bacterial species were identified in patient 5 Kurthia Gibsonii and patient 7 Pseudomonas aeruginosa. The detection of SRB in different dental tissues with distinct periodontal features demonstrated that new studies need to be developed in order to determine the true role of SRB in the oral microbiota. In addition, it was possible to verify the presence of Lactobacillus casei together with SRB in one sample. Host influence on germination and reproduction of the facultative hemi-parasitic weed Rhamphicarpa fistulosa.
Rice Vampireweed, Rhamphicarpa fistulosa, was a minor parasitic weed until recently when rice cultivation in sub-Saharan Africa was expanded into marginal wetlands, that are the parasite's natural habitat. Unlike most of the parasitic weeds, R. Ecological and evolutionary dynamics of a model facultative pathogen: Agrobacterium and crown gall disease of plants.
Many important pathogens maintain significant populations in highly disparate disease and non-disease environments. The consequences of this environmental heterogeneity in shaping the ecological and evolutionary dynamics of these facultative pathogens are incompletely understood. Agrobacterium tumefaciens, the causative agent for crown gall disease of plants has proven a productive model for many aspects of interactions between pathogens and their hosts and with other microbes.
In this review, we highlight how this past work provides valuable context for the use of this system to examine how heterogeneity and transitions between disease and non-disease environments influence the ecology and evolution of facultative pathogens. We focus on several features common among facultative pathogens, such as the physiological remodelling required to colonize hosts from environmental reservoirs and the consequences of competition with host and non-host associated microbiota. In addition, we discuss how the life history of facultative pathogens likely often results in ecological tradeoffs associated with performance in disease and non-disease environments.
These pathogens may therefore have different competitive dynamics in disease and non-disease environments and are subject to shifting selective pressures that can result in pathoadaptation or the within-host spread of avirulent phenotypes. Facultative anadromy in salmonids: Modeling and management of facultative anadromous salmonids is complicated by their ability to select anadromous or resident life histories.
Genetic and metabolic diversity of pink-pigmented facultative methylotrophs in phyllosphere of tropical plants. Results indicate that six diversified groups of PPFMs are found in these crops. Sunflower and maize phyllosphere harbor four different groups of methylobacteria while cotton has only two groups. Here, we report the whole-genome sequence and annotation of this organism, which consists of a single 5. Modified Hungate vessel made of native penicillinum bottles and chemical vessels has been created and experimentally studied.
The vessels can be used for cultivation of facultative and obligate anaerobe microorganisms on liquid and solid nutrient media. Locking devices of the vessel are described. Non-oral gram-negative facultative rods in chronic periodontitis microbiota. The subgingival prevalence of gram-negative facultative rods not usually inhabiting or indigenous to the oral cavity non-oral GNFR , as well as selected periodontal bacterial pathogens, were evaluated by culture in untreated and treated chronic periodontitis patients.
In order to analyze the biodiversity of cultivable facultative -alkaliphilic actinobacteria and the enzymes they produced. Total 10 soil samples were collected from saline-alkaline environments of Fukang, Xinjiang province. Facultative -alkaliphilic actinobacteria strains were isolated and identified by 16S rRNA gene sequence analysis. Enzymes including amylase, proteinase, xylanase, and cellulase were detected.
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Total facultative -alkaliphilic actinobacterial strains and 4 alkali-tolerant actinobacterial strains were isolated from the samples, and those strains were distributed within 22 genera in 13 families and 8 orders of actinobacteria based on their 16S rRNA gene sequence analysis. The ratio of non-predominant Streptomyces and Nocardiopsis strains were The positive rates of amylase, proteinase, xylanase and cellulase were Diverse facultative -alkaliphilic actinobacteria were discovered from saline-alkaline environments of Fukang.
Facultative -alkaliphilic actinobacteria are a potential source for enzymes. The study would facilitate the knowledge of the diversity of facultative -alkaliphilic actinobacteria, and provide the technical basis for exploration of facultative -alkaliphilic actinobacteria resources. Annales des Sciences Agronomiques: Identification of the facultative heterochromatic X chromosome in females of 25 rodent species.
Treatment of the chromosomes of 25 rodent species with a 50 degrees C hypotonic solution and Giemsa staining permitted identification of the heterochromatic X chromosome in 24 species.
With this technique, the facultative of the heterochromatic X chromosome or the facultative portion of large, composite-type X chromosoms is stained darker than the other chromosomes, allowing it to be distinguished from the homologous euchromatic X chromosome in female metaphase cells. Intense staining of the single X chromosome was not observed in male metaphase cells. It is suggested that this differential staining of one of the two X chromosomes might be due to qualitative differences in chromosomal proteins rather than to differences in the degree of chromosomal condensation or in DNA base sequence.
The utility of anaerobic blood culture in detecting facultative anaerobic bacteremia in children. Routine anaerobic blood culture is not recommended in children because obligate anaerobic bacteremia is rare in the pediatric population. However, a number of facultative anaerobic bacteria can cause community and hospital acquired infections in children and the utility of anaerobic blood culture for detection of these organisms is still unclear. Complete genome sequence of the aerobic facultative methanotroph Methylocella silvestris BL2.
Methylocella silvestris BL2 is an aerobic methanotroph originally isolated from an acidic forest soil in Germany. It is the first fully authenticated facultative methanotroph. It grows not only on methane and other one-carbon C 1 substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate. Here we report the full genome sequence of this bacterium. Tanvir; Dedysh, Svetlana N. Colin; Dunfield, Peter F. It grows not only on methane and other one-carbon C1 substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate.
Two aerobic, pink-pigmented, facultatively methylotrophic bacteria, strains F20T and RXM T , are described taxonomically. On the basis of their phenotypic and genotypic properties, the isolates are proposed as novel species of the genus Methylobacterium, Methylobacterium suomiense sp. Growth and enzymological characteristics of a pink-pigmented facultative methylotroph Methylobacterium sp.
Growth characteristics of batch and continuous cultures of the pink facultative methylotroph Methylobacterium sp.
The response of a chemostat culture to a pulse increase of methanol concentration was studied. Malate, succinate and oxaloacetate additions to the methanol-supplemented medium decreased batch culture growth inhibition by methanol. The carotenoid content in cells grown in a chemostat decreased with increasing growth rate.
The key enzyme activities of C1-metabolism were measured in a chemostat culture at different dilution rates. DNA hybridization studies on the pink-pigmented facultative methylotrophs.
A reproducible hybridization system was developed for the rapid analysis of multiple DNA samples. Results indicated that the PPFMs comprise four major and several minor homology groups, and that they should remain grouped in a single genus, Methylobacterium. The distribution of pink-pigmented facultative methylotrophs PPFMs on the leaves of various vegetables was studied. All kinds of vegetable leaves tested gave pink-pigmented colonies on agar plates containing methanol as sole carbon source.
Commercial green perilla, Perilla frutescens viridis Makino Makino, gave the highest coun A methodology was developed to analyze boundary conditions, the size of the mesh and the turbulence of a mathematical model of CFD, which could explain hydrodynamic behavior on facultative stabilization ponds, FSP, built to pilot scale: Models dispersion studies were performed in field for validation, taking samples into and out of the FSP, the information was used to carry out CFD model simulations of the three topologies.
Sex as a response to oxidative stress: The evolution of sex is one of the long-standing unsolved problems in biology. Although in many lineages sex is an obligatory part of the life cycle and is associated with reproduction, in prokaryotes and many lower eukaryotes, sex is facultative , occurs in response to stress and often involves the formation of a stress-resistant dormant form. The proximate and ultimate causes of the connection between stress and sex in facultatively sexual lineages are unclear.
Because most forms of stress r The studies on the biocontrol potential of pink pigmented facultative methylotrophic PPFM bacteria other than the genus Methylobacterium are scarce. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicate Modelisation des effets physico-techniques pour la conception des However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane.
We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata.
Full Text Available Methanotrophs are a specialized group of bacteria that can utilize methane CH4 as a sole energy source. Facultative parthenogenesis validated by DNA analyses in the green anaconda Eunectes murinus. In reptiles, the mode of reproduction is typically sexual. However, facultative parthenogenesis occurs in some Squamata, such as Komodo dragon Varanus komodoensis and Burmese python Python bivittatus.
Here, we report facultative parthenogenesis in the green anaconda Eunectes murinus. We found two fully developed female neonates and 17 undeveloped eggs in the oviduct of a female anaconda isolated from other individuals for eight years and two months at Ueno Zoo, Japan. To clarify the zygosity of the neonates, we analyzed 18 microsatellite markers of which 16 were informative.
We observed only maternal alleles and no paternal alleles for all 16 markers. To examine the possibility of the long-term sperm storage, we estimated allele frequencies in a putative parental stock by genotyping five unrelated founders. If all founders, including the mother, are originated from a single Mendelian population, then the probability that the neonates were produced by sexual reproduction with an unrelated male via long-term sperm storage was infinitesimally small 2.
We also examined samples from two additional offspring that the mother delivered eight years before her death. We consistently observed paternal alleles in these elder offspring, indicating that the mother had switched from sexual reproduction to asexual reproduction during the eight years of isolation. This is the first case of parthenogenesis in Eunectes to be validated by DNA analysis, and suggests that facultative parthenogenesis is widespread in the Boidae.
Full Text Available In reptiles, the mode of reproduction is typically sexual. An inquiry into the relationships among science , policy and the public: This thesis present an analysis of qualitative interviews with experts in the field of climate research in which the relation among science , policy and public is discussed. To begin, an overview of the methods and results of climate science is presented. Following, elements of the discourse among science , policy and public are presented in a manner that demonstrates the different ways to look at the problem of anthropogenic climate change.
Subsequently, approaches of the sociology of science are introduced in which science is examined as a social process. Here the question is raised up to what extent climate research has taken a problem oriented perspective in which social and political criteria in the treatment of actual risks of global change are taken into account.
The results of the analysis indicate that uncertainties in science led to different perspectives regarding the risks of anthropogenic climate change. In this way scientific knowledge itself becomes problematic. Communication of scientific results to policy and public poses a process which is stamped by individual values and preferences. This suggests the possibility that recognition of theories is increasingly determined by extra scientific criteria like resonance in the media and possibility of connection for political measures.
In einem ersten Schritt wird ein Ueberblick gegeben ueber Methoden und Ergebnisse der gegenwaertigen Klimaforschung. Anschliessend werden Elemente des Diskurses zwischen Wissenschaft, Politik und Oeffentlichkeit dargestellt, die unterschiedliche Selektionsmuster der Problematik um anthropogene Klimaaenderungen verdeutlichen. Hiervon ausgehend werden Ansaetze der Wissenschaftssoziologie vorgestellt, mit denen Wissenschaft als sozialer Prozess analysiert wird.
Hierbei wird die Frage. Effets des electrons secondaires sur l'ADN. Les interactions des electrons de basse energie EBE representent un element important en sciences des radiations, particulierement, les sequences se produisant immediatement apres l'interaction de la radiation ionisante avec le milieu biologique. Cependant, il n'y a jamais eu de mesures directes demontrant l'interaction de ces electrons de tres basse energie avec l'ADN, du principalement aux difficultes experimentales imposees par la complexite du milieu biologique.
Dans notre laboratoire, les dernieres annees ont ete consacrees a l'etude des phenomenes fondamentaux induits par impact des EBE sur differentes molecules simples e. D'autres travaux effectues recemment sur des bases de l'ADN et des oligonucleotides ont montre que les EBE produisent des bris moleculaires sur les biomolecules. Ces travaux nous ont permis d'elaborer des techniques pour mettre en evidence et comprendre les interactions fondamentales des EBE avec des molecules d'interet biologique, afin d'atteindre notre objectif majeur d'etudier l'effet direct de ces particules sur la molecule d'ADN.
Les techniques de sciences des surfaces developpees et utilisees dans les etudes precitees peuvent etre etendues et combinees avec des methodes classiques de biologie pour etudier les dommages de l'ADN induits par l'impact des EBE. Nos experiences ont montre l'efficacite des electrons de eV a induire des coupures simple et double brins dans l'ADN.
Pour des energies inferieures a 15 eV, ces coupures sont induites par la localisation temporaire d'un electron sur une unite moleculaire de l'ADN, ce qui engendre la formation d'un ion negatif transitoire. Etude comparative de la flore aux abords des cours d'eau dans les In the field of education, master and doctoral studies are considered too lengthy, and the dropout rate too high. One solution for improving the situation is to support supervision of studies. Data have been collected through semi-directive interviews and questionnaires distributed to research directors and students.
The results highlight good practices and difficulties. The institution does provide support for the pursuit of studies and various aspects of scientific networking. It involves elements from theories of social interaction; social psychology of development and cognitive functioning; and research in natural- science teaching methods which acknowledge the importance and fundamental role of social interaction in the development of cognitive operations and learning.
The study also presents some of the more significant results of the research carried out on different aspects of this topic. The discussion unfolded here supports the hypothesis that the construction of natural-scientific knowledge at the pre-school age and corresponding scholastic activities are necessary and effective.
Civili, langue des Baloango. Sincerely, Louise Lemyre, Ph. Des racines et des ailes. Long-distance commuting patterns, or how to conciliate professional and personal lifeLong-distance commuting patterns appear to be increasing in Europe over the last ten years. These raising mobility patterns lead to reappraise the Zahavi conjecture and appear largely inexplicable by the classical rational actor paradigm traditionally used in transportation research. In literature, commuting is mainly explained by residential contexts, urban forms and job.
Nevertheless this theoretical frame says little about the decision-making processes themselves. Based on a qualitative survey conducted in three European countries - France, Belgium and Switzerland — among a population of high commuters, this paper proposes an analysis of. Epinephrine mediates facultative carbohydrate-induced thermogenesis in human skeletal muscle. The thermic effect of carbohydrate has a component mediated by the sympathoadrenal system but of unknown anatomical localization. The present study provides evidence of a facultative thermogenic component in skeletal muscle, mediated by epinephrine via beta 2-adrenoreceptors.
However, it also points to a nonmuscle component mediated through beta 1-adrenoceptors Consequently, the sympathoadrenal system seems to play a physiological role in the daily energy balance Characterization of 12 polymorphic microsatellite markers for a facultatively eusocial sweat bee Megalopta genalis. We developed a library of twelve polymorphic di- and tri-nucleotide microsatellite markers for Megalopta genalis, a facultatively eusocial sweat bee. We tested each locus in a panel of 23 unrelated females and found alleles per locus. Observed and expected heterozygosities ranged from 0.
None of the loci deviated from Hardy-Weinberg equilibrium proportions or was found to be in gametic disequilibrium. Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly Bemisia tabaci in some populations through mechanisms that are not yet understood.
In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. Experiments using plants coated with P. These results suggest that P. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects.
Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2. The molecular regulation of methane oxidation in the first fully authenticated facultative methanotroph Methylocella silvestris BL2 was assessed during growth on methane and acetate. Problems of poor growth of Methylocella spp. The genes encoding soluble methane monooxygenase were cloned and sequenced, which revealed that the structural genes for soluble methane monooxygenase, mmoXYBZDC, were adjacent to two genes, mmoR and mmoG, encoding a sigma54 transcriptional activator and a putative GroEL-like chaperone, located downstream 3' of mmoC.
Transcriptional analysis revealed that the genes were all cotranscribed from a sigmadependent promoter located upstream 5' of mmo X. The transcriptional start site was mapped.