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991.
Xylose anaerobic conversion by open-mixed cultures 总被引:1,自引:0,他引:1
Margarida F. Temudo Tania Mato Robbert Kleerebezem Mark C. M. van Loosdrecht 《Applied microbiology and biotechnology》2009,82(2):231-239
Xylose is, after glucose, the dominant sugar in agricultural wastes. In anaerobic environments, carbohydrates are converted
into volatile fatty acids and alcohols. These can be used as building blocks in biotechnological or chemical processes, e.g.,
to produce bioplastics. In this study, xylose fermentation by mixed microbial cultures was investigated and compared with
glucose under the same conditions. The product spectrum obtained with both substrates was comparable. It was observed that,
in the case of xylose, a higher fraction of the carbon was converted into catabolic products (butyrate, acetate, and ethanol)
and the biomass yield was approximately 20% lower than on glucose, 0.16 versus 0.21 Cmol X/Cmol S. This lower yield is likely
related to the need of an extra ATP during xylose uptake. When submitted to a pulse of glucose, the population cultivated
on xylose could instantaneously convert the glucose. No substrate preference was observed when glucose and xylose were fed
simultaneously to the continuously operated bioreactor. 相似文献
992.
Two new species of the genus Quadroppia Jacot, 1939, Quadroppia (Coronoquadroppia) squarrosa sp. n. and Quadroppia (Quadroppia) foveolata sp. n. are described and illustrated from Turkey. They were collected from soil and litter under pear trees (Pyrus communis) and moss on rock, respectively. 相似文献
993.
Tayvich Vorapreeda Chinae Thammarongtham Kobkul Laoteng 《World journal of microbiology & biotechnology》2016,32(7):122
Lipid-degrading or lipolytic enzymes have gained enormous attention in academic and industrial sectors. Several efforts are underway to discover new lipase enzymes from a variety of microorganisms with particular catalytic properties to be used for extensive applications. In addition, various tools and strategies have been implemented to unravel the functional relevance of the versatile lipid-degrading enzymes for special purposes. This review highlights the study of microbial lipid-degrading enzymes through an integrative computational approach. The identification of putative lipase genes from microbial genomes and metagenomic libraries using homology-based mining is discussed, with an emphasis on sequence analysis of conserved motifs and enzyme topology. Molecular modelling of three-dimensional structure on the basis of sequence similarity is shown to be a potential approach for exploring the structural and functional relationships of candidate lipase enzymes. The perspectives on a discriminative framework of cutting-edge tools and technologies, including bioinformatics, computational biology, functional genomics and functional proteomics, intended to facilitate rapid progress in understanding lipolysis mechanism and to discover novel lipid-degrading enzymes of microorganisms are discussed. 相似文献
994.
995.
The chitosan with three-dimensional porous structure greatly increased the effective electrode surface for loading of platinum
nanoparticles and promoted efficient electron transfer. The resulting biosensor had a response time (within 5 s) and a linear
response from 6 μM to 4.2 mM glucose with a detection limit of 2 μM (S/N = 3). Moreover, the methodology can be applied for
the immobilization of other enzymes. 相似文献
996.
Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues
in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility
and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role
in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is an
almost ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental
cues. In the last 20 years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic
models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth
is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are
studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based
models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making
the lattice size variable over time. A reaction–diffusion master equation formalism is generalised to the case of growing
lattices and used in the derivation of the macroscopic PDEs. 相似文献
997.
Andrew J. Ghio 《Biometals》2016,29(5):751-779
Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam’s razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron. 相似文献
998.
Aleksandra Topic Marina Milenkovic Snezana Uskokovic-Markovic Dragana Vucicevic 《Biological trace element research》2010,134(3):296-306
Investigations of effective, orally active, and safe antidiabetic metallopharmaceuticals have been carried out during the
last two decades. It has been reported that tungsten compounds mimic the action of insulin in intact cell systems. As insulin
mimetics, the most investigated tungsten compound was sodium tungstate (ST), rarely investigated was tungstophosphoric acid
(WPA), but never alanine complex of tungstophosphoric acid (WPA-A). In this study, the insulin mimetic activity of three different
tungsten compounds, ST, WPA, and WPA-A, was evaluated by means of in vitro measurements of the glucose uptake and inhibition
of free fatty acids release from epinephrine-treated isolated rat white adipocytes. We investigated the influence of concentration
(lower and higher, 0.1 and 1.0 mM, respectively) and solvent: isotonic salt solution—saline (0.9% w/v of NaCl) and dimethyl sulfoxide (DMSO; 2% v/v), on the biological effect of tested compounds. Our experimental data showed that all of the three investigated tungsten
compounds possess insulin mimetic activity in vitro on the isolated adipocytes. Influence of concentration and solvents on
insulin mimetic effect for the certain tungsten compounds were: WPA was shown effect independently of concentration and solvents;
higher concentration and DMSO were significant decreasing insulin mimetic effect of ST; lower concentration and saline led
to decreasing effect of WPA-A. Generally, there were no differences in insulin mimetic effect of three tungsten compounds
in lower concentration and dissolved in DMSO. When saline was used as solvent, it was needed higher concentration of investigated
compounds to accomplish the same effect. In conclusion, our results suggest that low concentration (0.1 mM) of ST, WPA, and
WPA-A dissolved in 2% DMSO could be the good candidates for in vivo investigation of their antidiabetic properties. 相似文献
999.
1000.
Natalia Buier 《Dialectical Anthropology》2018,42(3):257-275
This article presents an analysis of the relationship between historical memory and the emergence and reproduction of a specific model of unionism. I argue that in order to understand the militant particularism of the Spanish engine drivers, we need to look at the historical representations that it is embedded in. Recourse to a generational framework makes possible the sustained presentation of the union as a case of successful workers’ organizing, in spite of evidence to the contrary. The historical ethnographic analysis of SEMAF, the Spanish engine drivers’ union, contributes to the analysis of historical memory within the contemporary anthropology of class. The article contributes to theoretical debates in the anthropology of class by reclaiming Michel Trouillot’s conceptualization of the historical process. Two aspects of Trouillot’s work are singled out: his dynamic understanding of the process of historical production and the corollary formulation of the overlapping capacities in which people participate in it (as agents, actors, and subjects) and his emphasis on the importance of expanding scholarly views of the field of historical production. 相似文献