Osmoadaptation mechanisms in prokaryotes: distribution of compatible solutes

Microorganisms respond to osmotic stress mostly by accumulating compatible solutes, either by uptake from the medium or by de novo synthesis. These osmotically activ molecules preserve the positive turgor pressure required for cell division. The diversity of compatible solutes is large but falls into a few major chemical categories; they are usually small organic molecules such as amino acids or their derivatives, and carbohydrates and their derivatives. Some are widely distributed in nature while others seem to be exclusively present in specific groups of organisms. This review discusses the diversity and distribution of known classes of compatible solutes found in prokaryotes as well as the increasing knowledge of the genes and pathways involved in their synthesis. The alternative roles of some archetypal compatible solutes not subject to osmoregulatory constraints are also discussed

Diversity and biosynthesis of compatible solutes in hyper/thermophiles

The accumulation of compatible solutes, either by uptake from the medium or by de novo synthesis, is a general response of microorganisms to osmotic stress. The diversity of compatible solutes is large but falls into a few major chemical categories, such as carbohydrates or their derivatives and amino acids or their derivatives. This review deals with compatible solutes found in thermophilic or hyperthermophilic bacteria and archaea that have not been commonly identified in microorganisms growing at low and moderate temperatures. The response to NaCl stress of Thermus thermophilus is an example of how a thermophilic bacterium responds to osmotic stress by compatible solute accumulation. Emphasis is made on the pathways leading to the synthesis of mannosylglycerate and glucosylglycerate that have been recently elucidated in several hyper/thermophilic microorganisms. The role of compatible solutes in the thermoprotection of these fascinating microorganisms is also discussed. [Int Microbiol 2006; 9(3):199-206

Diversity, distribution and biosynthesis of compatible solutes in prokaryotes

Els microorganismes responen a l'estrès osmòtic acumulant, principalment, soluts compatibles, agafant-los del medi o per síntesi de novo. Aquestes molècules, osmòticament actives, conserven la pressió de turgència positiva necessària per a la divisió cel·lular. La diversitat de soluts compatibles és gran, però es divideix en unes quantes categories químiques essencials; són molècules orgàniques normalment petites, com els aminoàcids, o els seus derivats, i els carbohidrats, o els seus derivats. Alguns són àmpliament distribuïts en la natura, mentre que d'altres sembla que siguin presents exclusivament en grups específics d'organismes. Aquesta revisió parla de la diversitat i la distribució de classes conegudes de soluts compatibles trobats en procariotes, així com del coneixement creixent dels gens i les rutes que s'impliquen en la seva síntesi. També es parla de les rutes alternatives d'alguns soluts compatibles no subjectes a restriccions osmoregulatòries.Microorganisms respond to osmotic stress mostly by accumulating compatible solutes, either by uptake from the medium or by de novo synthesis. These osmotically active molecules preserve the positive turgor pressure required for cell division. The diversity of compatible solutes is large but falls into a few major chemical categories; they are usually small organic molecules such as amino acids or their derivatives, and carbohydrates or their derivatives. Some are widely distributed in nature while others seem to be exclusively present in specific groups of organisms. This review discusses the diversity and distribution of known classes of compatible solutes found in prokaryotes as well as the increasing knowledge of the genes and pathways involved in their synthesis. The alternative roles of some archetypal compatible solutes not subject to osmoregulatory constraints are also discussed

Sharp convergence for degenerate Langevin dynamics

In this paper, we study an ordinary differential equation with a degenerate global attractor at the origin, to which we add a white noise with a small parameter that regulates its intensity. Under general conditions, for any fixed intensity, as time tends to infinity, the solution of this stochastic dynamics converges exponentially fast in total variation distance to a unique equilibrium distribution. We suitably accelerate the random dynamics and show that the preceding convergence is sharp, that is, the total variation distance of the accelerated random dynamics and its equilibrium distribution tends to a decreasing profile, which corresponds to the total variation distance between the marginal of a stochastic differential equation that comes down from infinity and its corresponding equilibrium distribution. In particular, there is no cutoff phenomenon for this one-parameter family of random processes.Comment: 37 page

Trehalose biosynthesis in Thermus thermophilus RQ-1: biochemical properties of the trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase

The genes for trehalose synthesis in Thermus thermophilus RQ-1, namely otsA [trehalose-phosphate synthase (TPS)], otsB [trehalose-phosphate phosphatase (TPP)], and treS [trehalose synthase (maltose converting) (TreS)] genes are structurally linked. The TPS/TPP pathway plays a role in osmoadaptation, since mutants unable to synthesize trehalose via this pathway were less osmotolerant, in trehalose-deprived medium, than the wild-type strain. The otsA and otsB genes have now been individually cloned and overexpressed in Escherichia coli and the corresponding recombinant enzymes purified. The apparent molecular masses of TPS and TPP were 52 and 26 kDa, respectively. The recombinant TPS utilized UDP-glucose, TDP-glucose, ADP-glucose, or GDP-glucose, in this order as glucosyl donors, and glucose-6-phosphate as the glucosyl acceptor to produce trehalose-6-phosphate (T6P). The recombinant TPP catalyzed the dephosphorylation of T6P to trehalose. This enzyme also dephosphorylated G6P, and this activity was enhanced by NDP-glucose. TPS had an optimal activity at about 98°C and pH near 6.0; TPP had a maximal activity near 70°C and at pH 7.0. The enzymes were extremely thermostable: at 100°C, TPS had a half-life of 31 min, and TPP had a half-life of 40 min. The enzymes did not require the presence of divalent cations for activity; however, the presence of Co 2+ and Mg 2+ stimulates both TPS and TPP. This is the first report of the characterization of TPS and TPP from a thermophilic organism

A Faculdade de Direito no espelho : o dilema do racismo institucional

O racismo institucional atravessa todas as instituições públicas e privadas, tangíveis ou intangíveis de nossa sociedade; queremos com essa pesquisa analisar quais são os possíveis mecanismos e dispositivos que tornam essa relação intrínseca da Faculdade de Direito da Universidade Federal do Rio Grande do Sul (UFRGS), com o fenômeno do racismo institucional e sua postura ante aos desafios trazido pela ampliação e reserva de vagas, sobretudo, pelo ingresso de estudantes negros e pardos oriundos de escolas públicas e de realidades socioculturais tão diferentes daquelas experimentadas até então. Para responder a este objetivo, propõem-se enquanto objetivos específicos: a) identificar as diversas manifestações características do racismo, (institucional, interpessoal, pessoal e cientifico) e da branquitude, verificados nesta instituição, bem como, no processo de formação profissional b) analisar conceitos e instituições e movimentos que sirvam para ampliar a compreensão do fenômeno do racismo, quanto instrumento de exclusão, assimilação, permanências e rupturas; c) analisar as práticas de enfrentamento ao racismo na promoção e/ou implementação das políticas de ação afirmativa, principalmente no que tange a educação antirracista.Le racisme institutionnel traverse toutes les institutions publiques et privées, matérielles ou immatérielles, de notre société ; Avec cette recherche, nous voulons analyser quels sont les mécanismes et dispositifs possibles qui rendent cette relation intrinsèque de la Faculté de droit de l'Université fédérale de Rio Grande do Sul (UFRGS), avec le phénomène du racisme institutionnel et sa posture face à des défis posés par l'expansion et la réservation des places vacantes, surtout en raison de l'admission d'élèves noirs et bruns des écoles publiques et de réalités socioculturelles si différentes de celles vécues jusqu'alors. Pour répondre à cet objectif, les objectifs spécifiques suivants sont proposés : a) identifier les différentes manifestations caractéristiques du racisme (institutionnel, interpersonnel, personnel et scientifique) et de la blancheur, vérifiées dans cette institution, ainsi que dans le processus de formation professionnelle b ) analyser les concepts et les institutions et mouvements qui servent à élargir la compréhension du phénomène du racisme, en tant qu'instrument d'exclusion, d'assimilation, de permanence et de ruptures ; c) analyser les pratiques de lutte contre le racisme dans la promotion et/ou la mise en œuvre de politiques d'action positive, notamment en matière d'éducation antiraciste

Análise das decisões do superior tribunal de justiça sobre adoção à brasileira

A presente pesquisa tem como tema a adoção à brasileira, uma prática pela qual registra-se como próprio filho alheio. Na pesquisa busca-se identificar os motivos que levam as pessoas a recorrerem a esse tipo de adoção, já que não possui regulamentação e, sim, tipificação como crime contra o estado de filiação. Com isso em mente, através de exploração bibliográfica, primeiro é feito uma apresentação dos aspectos históricos, dos princípios e dos procedimentos relacionados à adoção regular. Em seguida, parte-se para o principal objetivo do estudo, saber o posicionamento do Superior Tribunal de Justiça em face da adoção à brasileira, uma vez que se acredita na possibilidade de "convalidação" da adoção diante dos princípios da afetividade e do melhor interesse da criança e adolescente. Para tanto, são analisados seis acórdãos proferidos durante os anos de 2020 e 2021, no intuito de averiguar os argumentos dos ministros para decidirem sobre a manutenção ou não da criança com a família registral. Sendo que ao fim, foi possível descobrir que o Tribunal, diante do caso em concreto, tem o posicionamento de manter o infante com a família registral, quando os laços afetivos já se consolidaram e não há elementos que demonstrem riscos físicos e psicológicos à criança

Complete genome sequence of Tessaracoccus sp. Strain T2.5-30 isolated from 139.5 meters deep on the subsurface of the Iberian Pyritic Belt

Here, we report the complete genome sequence of Tessaracoccus sp. strain T2.5-30, which consists of a chromosome with 3.2 Mbp, 70.4% G C content, and 3,005 coding DNA sequences. The strain was isolated from a rock core retrieved at a depth of 139.5 m in the subsurface of the Iberian Pyritic Belt (Spain)This work was supported by the Foundation for Science and Technology (FCT), Portugal (doctoral fellowship SFRH/BD/87076/2012 to T.L.) and by ERC Advanced grant IPBSL-25035