Search results for "iOS"

Biotechnology of Rhodococcus for the production of valuable compounds

2020

Abstract Bacteria belonging to Rhodococcus genus represent ideal candidates for microbial biotechnology applications because of their metabolic versatility, ability to degrade a wide range of organic compounds, and resistance to various stress conditions, such as metal toxicity, desiccation, and high concentration of organic solvents. Rhodococcus spp. strains have also peculiar biosynthetic activities that contribute to their strong persistence in harsh and contaminated environments and provide them a competitive advantage over other microorganisms. This review is focused on the metabolic features of Rhodococcus genus and their potential use in biotechnology strategies for the production o…

Microbiological transformations. 30. Enantioselective hydrolysis of racemic epoxides: the synthesis of enantiopure insect juvenile hormone analogs (b…

1993

Abstract The enantioselective epoxide biohydrolysis of the racemic benzodioxole 6,7-epoxygeraniol derivative 1 has been achieved using the fungus A. niger . This new type of preparative scale bioconversion allows the synthesis of both enantiomers of Bower's compound, an analogue of insect juvenile hormone. Biological tests showed that the 6(R) enantiomer was about ten times more active than the 6(S) enantiomer against the yellow meal worm Tenebrio molitor .

Minor changes in the macrocyclic ligands but major consequences on the efficiency of gold nanoparticles designed for radiosensitization

2016

International audience; Many studies have been devoted to adapting the design of gold nanoparticles to efficiently exploit their promising capability to enhance the effects of radiotherapy. In particular, the addition of magnetic resonance imaging modality constitutes an attractive strategy for enhancing the selectivity of radiotherapy since it allows the determination of the most suited delay between the injection of nanoparticles and irradiation. This requires the functionalization of the gold core by an organic shell composed of thiolated gadolinium chelates. The risk of nephrogenic systemic fibrosis induced by the release of gadolinium ions should encourage the use of macrocyclic chelat…

Blood Flow and Tissue Oxygenation of Human Tumors: An Update

1992

It is generally accepted that tumor microcirculation, blood flow, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status (factors which are usually closely linked and which define the so-called cellular microenvironment) can markedly influence the therapeutic response of malignant tumors. Tumor blood flow is the major determinant for intra-tumor pharmacokinetics and (through modulation of the cellular microenvironment) of pharmacody-namics. The oxygen supply greatly determines the radiosensitivity of the tumors to be treated. The oxygen enhancement ratio, i.e., the ratio of doses with and without oxygen to produce the same biological effect is 2.7 to 3.0. O2 partial…

Sensory hybrid host materials for the selective chromo-fluorogenic detection of biogenic amines

2006

[EN] Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment.

Quantifying biogeochemical heterogeneity in soil systems

2018

© 2018 Elsevier B.V. Soils are increasingly perceived as complex systems with properties and biogeochemical functions that vary on millimeter scales. Quantitative information about the resulting biogeochemical heterogeneity is needed to improve process knowledge and to render biogeochemical models more mechanistic. Here we demonstrate how standardized arrays of Pt-electrodes can be used to quantify biogeochemical or ‘functional’ soil heterogeneity, defined as the extent to which the soil is subdivided into microenvironments. Our case study confirmed the validity of this approach for a soil sequence consisting of a well-drained, a moderately well drained and a poorly drained Mollisol. We fou…

Iron isotope signature of magnetofossils and oceanic biogeochemical changes through the Middle Eocene Climatic Optimum.

2021

21 pages; International audience; Magnetotactic bacteria (MTB) intracellularly precipitate magnetite (Fe3O4) crystals that can be preserved in the geological record. When MTB die, the so-called magnetofossils constitute valuable proxies for paleoenvironmental reconstructions and are suspected to represent some of the oldest traces of biomineralization on Earth. Yet, the biogenicity of putative magnetofossils found in ancient terrestrial and extra-terrestrial samples is still largely debated and their significance for past climate still holds uncertainties. Here we studied a sedimentary sequence from the Indian Ocean (ODP Hole 711A) recording the Middle Eocene Climatic Optimum (MECO) through…

2018

AbstractWhile significant efforts have been invested in reconstructing the early evolution of the Earth’s atmosphere–ocean–biosphere biogeochemical nitrogen cycle, the potential role of an early continental contribution by a terrestrial, microbial phototrophic biosphere has been largely overlooked. By transposing to the Archean nitrogen fluxes of modern topsoil communities known as biological soil crusts (terrestrial analogs of microbial mats), whose ancestors might have existed as far back as 3.2 Ga ago, we show that they could have impacted the evolution of the nitrogen cycle early on. We calculate that the net output of inorganic nitrogen reaching the Precambrian hydrogeological system c…

Transcriptome changes induced by Arbuscular mycorrhizal symbiosis in leaves of durum wheat (Triticum durum Desf.) promote higher salt tolerance

2022

AbstractThe salinity of soil is a relevant environmental problem around the world, with climate change raising its relevance, particularly in arid and semiarid areas. Arbuscular Mycorrhizal Fungi (AMF) positively affect plant growth and health by mitigating biotic and abiotic stresses, including salt stress. The mechanisms through which these benefits manifest are, however, still unclear. This work aimed to identify key genes involved in the response to salt stress induced by AMF using RNA-Seq analysis on durum wheat (Triticum turgidum L. subsp. durum Desf. Husn.). Five hundred sixty-three differentially expressed genes (DEGs), many of which involved in pathways related to plant stress resp…

Comparative genomics between two insect symbiotic models: Innate immune system and amino acid biosynthetic pathways of the rice weevil Sitophilus ory…

2019

Los insectos se pueden encontrar en la mayoría de los ecosistemas del planeta y son capaces de aprovechar prácticamente cualquier fuente de alimento. Son el grupo de animales más diverso con un número de especies estimado en cinco millones. Todos los insectos comparten un mismo plan corporal que consiste en tres segmentos (cabeza, tórax y abdomen), tres pares de patas, un par de antenas y ojos compuestos; sin embargo, cada especie tiene partes especializadas acordes con su estilo de vida. A pesar de que los insectos son capaces de aprovechar múltiples fuentes de alimento, en múltiples ocasiones dependen de compañeros microbianos para obtener nutrientes escasos en su dieta. Por ello, la simb…