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71.
72.
Peter J. Humphries Simone Linz Charles Semple 《Bulletin of mathematical biology》2013,75(10):1879-1890
Recently, we have shown that calculating the minimum–temporal-hybridization number for a set ${\mathcal{P}}$ of rooted binary phylogenetic trees is NP-hard and have characterized this minimum number when ${\mathcal{P}}$ consists of exactly two trees. In this paper, we give the first characterization of the problem for ${\mathcal{P}}$ being arbitrarily large. The characterization is in terms of cherries and the existence of a particular type of sequence. Furthermore, in an online appendix to the paper, we show that this new characterization can be used to show that computing the minimum–temporal hybridization number for two trees is fixed-parameter tractable. 相似文献
73.
Teresa Braunwald Lisa Schwemmlein Simone Graeff-Hönninger William Todd French Rafael Hernandez William E. Holmes Wilhelm Claupein 《Applied microbiology and biotechnology》2013,97(14):6581-6588
Due to the increasing demand for sustainable biofuels, microbial oils as feedstock for the transesterification into biodiesel have gained scientific and commercial interest. Also, microbial carotenoids have a considerable market potential as natural colorants. The carbon to nitrogen (C/N) ratio of the respective cultivation media is one of the most important parameters that influence the production of microbial lipids and carotenoids. Thus, in the present experiment, the influence of different C/N ratios, initial glucose loadings, and ammonium concentrations of the cultivation medium on microbial cell growth and lipid and carotenoid production by the oleaginous red yeast Rhodotorula glutinis has been assessed. As a general trend, both lipid and carotenoid production increased at high C/N ratios. It was shown that not only the final C/N ratio but also the respectively applied initial carbon and nitrogen contents influenced the observed parameters. The lipid yield was not affected by different ammonium contents, while the carotenoid production significantly decreased both at low and high levels of ammonium supply. A glucose-based increase from C/N 70 to 120 did not lead to an increased lipid production, while carotenoid synthesis was positively affected. Generally, it can be asserted that lipid and carotenoid synthesis are stimulated at higher C/N ratios. 相似文献
74.
Isabella V. Miller Graca Raposo Ulrich Welsch Olivia Prazeres da Costa Uwe Thiel Maria Lebar Martina Maurer Hans‐Ulrich Bender Irene von Luettichau Günther H. S. Richter Stefan Burdach Thomas G. P. Grunewald 《Biology of the cell / under the auspices of the European Cell Biology Organization》2013,105(7):289-303
75.
Capsule A newly created wetland has been beneficial for the breeding of five heron species and for the settlement and expansion of Glossy Ibises in the region. Aim To determine whether created wetland would lead to the establishment of a heron and ibis breeding colony, and if so, to determine its effects on the distribution of these species in the wider region. Methods Number of pairs breeding at the new wetland and in the region were estimated annually from 1996 to 2008. We investigated whether the growth of the new colony was explained by redistribution of breeding pairs within the region. Results Purple Herons, Squacco Herons and Glossy Ibises colonised the new wetland in 1996. Black‐crowned Night Herons settled in 1998, while Cattle and Little Egrets were the last species to establish in the mixed colony in 2001. The population increase was particularly marked for Glossy Ibises (which had bred in Doñana only sporadically through the 20th century). Our findings suggest that simple redistribution of pairs does not explain the formation and growth of the new colony. Since the first year of establishment numbers of Glossy Ibises and Purple Herons have shown a significant growth trend at both the new colony and in Doñana. Conclusion The creation and management of a new wetland has been successful for the conservation of heron and egret species and promoted the expansion of the Glossy Ibis population across the western Mediterranean region. 相似文献
76.
Generations of scientists have been captivated by ion channels and how they control the workings of the cell by admitting ions from one side of the cell membrane to the other. Elucidating the molecular determinants of ion conduction and selectivity are two of the most fundamental issues in the field of biophysics. Combined with ongoing progress in structural studies, modeling and simulation have been an integral part of the development of the field. As of this writing, the relentless growth in computational power, the development of new algorithms to tackle the so-called rare events, improved force-field parameters, and the concomitant increasing availability of membrane protein structures, allow simulations to contribute even further, providing more-complete models of ion conduction and selectivity in ion channels. In this report, we give an overview of the recent progress made by simulation studies on the understanding of ion permeation in selective and nonselective ion channels. 相似文献
77.
Isabella Daidone Massimiliano Aschi Maria Patamia Argante Bozzi Raffaele Petruzzelli 《Biopolymers》2013,99(1):47-54
Obtustatin and Lebestatin are lysine‐threonine‐serine (KTS)‐disintegrins, which are a family of low molecular weight polypeptides present in many viperidae venoms and are potent and specific inhibitors of collagen‐binding integrins. The integrin binding loop, harboring the 21KTS23 motif, and the C‐terminal tail are known to be responsible for the selective binding to the α1β1 integrin. Despite a very high sequence homology (only two mutations are present in Lebestatin relative to Obtustatin, namely R24L and S38L), Lebestatin exhibits a higher inhibitory effect than Obtustatin on cell adhesion and cell migration to collagens I and IV. Here we show, by means of molecular dynamics simulations of the two polypeptides in aqueous solution, that Lebestatin possesses a higher flexibility of the C‐terminal tail and a greater solvent accessibility of the integrin binding loop than Obtustatin. It may be hypothesized that these properties may contribute to the higher binding‐affinity of Lebestatin to its biological partner. © 2012 Wiley Periodicals, Inc. 相似文献
78.
Federica Prati Manuela Bartolini Elena Simoni Angela De Simone Antonella Pinto Vincenza Andrisano Maria Laura Bolognesi 《Bioorganic & medicinal chemistry letters》2013,23(23):6254-6258
The anti-amyloid properties shared by several quinones inspired the design of a new series of hybrids derived from the multi-target drug candidate memoquin (1). The hybrids consist of a central benzoquinone core and a fragment taken from non-steroidal anti-inflammatory drugs, connected through polyamine linkers. The new hybrids retain the potent anti-aggregating activity of the parent 1, while exhibiting micromolar AChE inhibitory activities. Remarkably, 2, 4, (R)-6 and (S)-6 were Aβ aggregation inhibitors even more potent than 1. The balanced amyloid/cholinesterase inhibitory profile is an added value that makes the present series of compounds promising leads against Alzheimer’s disease. 相似文献
79.
Simona Maria Monti Giuseppina De Simone Nina A. Dathan Martha Ludwig Daniela Vullo Andrea Scozzafava Clemente Capasso Claudiu T. Supuran 《Bioorganic & medicinal chemistry letters》2013,23(6):1626-1630
Several β-carbonic anhydrases (CAs, EC 4.2.1.1) are present in all land plants examined thus far. Here we report the first detailed biochemical characterization of one such isoform, FbiCA 1, from the C4 plant Flaveria bidentis, which was cloned, purified and characterized as recombinant protein. FbiCA 1 has an interesting CO2 hydrase catalytic activity (kcat of 1.2 × 105 and kcat/Km of 7.5 × 106 M?1 × s?1) and was moderately inhibited by most simple/complex inorganic anions. Potent FbiCA 1 inhibitors were also detected, such as trithiocarbonate, diethyldithiocarbamate, sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid (KIs in the range of 4–60 μM). Such inhibitors may be used as tools to better understand the role of various β-CA isoforms in photosynthesis. 相似文献
80.
Simone Guglielmetti Roberto Basilico Valentina Taverniti Stefania Arioli Claudia Piagnani Andrea Bernacchi 《World journal of microbiology & biotechnology》2013,29(11):2025-2032
In order to preserve environmental quality, alternative strategies to chemical-intensive agriculture are strongly needed. In this study, we characterized in vitro the potential plant growth promoting (PGP) properties of a gamma-proteobacterium, named MIMR1, originally isolated from apple shoots in micropropagation. The analysis of the 16S rRNA gene sequence allowed the taxonomic identification of MIMR1 as Luteibacter rhizovicinus. The PGP properties of MIMR1 were compared to Pseudomonas chlororaphis subsp. aurantiaca DSM 19603T, which was selected as a reference PGP bacterium. By means of in vitro experiments, we showed that L. rhizovicinus MIMR1 and P. chlororaphis DSM 19603T have the ability to produce molecules able to chelate ferric ions and solubilize monocalcium phosphate. On the contrary, both strains were apparently unable to solubilize tricalcium phosphate. Furthermore, the ability to produce 3-indol acetic acid by MIMR1 was approximately three times higher than that of DSM 19603T. By using fluorescent recombinants of strains MIMR1 and DSM 19603T, we also demonstrated that both bacteria are able to abundantly proliferate and colonize the barley rhizosphere, preferentially localizing on root tips and in the rhizoplane. Finally, we observed a negative effect of DSM 19603T on barley seed germination and plant growth, whereas MIMR1, compared to the control, determined a significant increase of the weight of aerial part (+22 %), and the weight and length of roots (+53 and +32 %, respectively). The results obtained in this work make L. rhizovicinus MIMR1 a good candidate for possible use in the formulation of bio-fertilizers. 相似文献