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981.
Evgeniy V. Dubrovin Anastasia V. Popova Sergey V. Kraevskiy Sergei G. Ignatov Tatyana E. Ignatyuk Igor V. Yaminsky Nikolay V. Volozhantsev 《PloS one》2012,7(10)
Background
Acinetobacter baumannii is known for its ability to develop resistance to the major groups of antibiotics, form biofilms, and survive for long periods in hospital environments. The prevalence of infections caused by multidrug-resistant A. baumannii is a significant problem for the modern health care system, and application of lytic bacteriophages for controlling this pathogen may become a solution.Methodology/Principal Findings
In this study, using atomic force microscopy (AFM) and microbiological assessment we have investigated A. baumannii bacteriophage AP22, which has been recently described. AFM has revealed the morphology of bacteriophage AP22, adsorbed on the surfaces of mica, graphite and host bacterial cells. Besides, morphological changes of bacteriophage AP22-infected A. baumannii cells were characterized at different stages of the lytic cycle, from phage adsorption to the cell lysis. The phage latent period, estimated from AFM was in good agreement with that obtained by microbiological methods (40 min). Bacteriophage AP22, whose head diameter is 62±1 nm and tail length is 88±9 nm, was shown to disperse A. baumannii aggregates and adsorb to the bacterial surface right from the first minute of their mutual incubation at 37°C.Conclusions/Significance
High rate of bacteriophage AP22 specific adsorption and its ability to disperse bacterial aggregates make this phage very promising for biomedical antimicrobial applications. Complementing microbiological results with AFM data, we demonstrate an effective approach, which allows not only comparing independently obtained characteristics of the lytic cycle but also visualizing the infection process. 相似文献982.
The large Southeast Asian genus Desmoxytes is slightly rediagnosed. A number of troglomorphic, most likely troglobitic, species occur in southern China. A key is provided to all 10 Desmoxytes spp. currently known from China, including three new presumed troglobites: Desmoxytes eupterygotasp. n. from Hunan Province, as well as Desmoxytes spinissimasp. n. and Desmoxytes luisp. n. from Guangxi Province. "Desmoxytes" philippina Nguyen Duc & Sierwald, 2010, from the Philippines, is formally removed from Desmoxytes, but not assigned to another genus. It probably belongs in a new genus in the subfamily Australiosomatinae, tribe Antichiropodini, close to the Bornean Euphyodesmus Attems, 1931 and Borneochiropus Golovatch, 1996. 相似文献
983.
Boudko SP Engel J Bächinger HP 《The international journal of biochemistry & cell biology》2012,44(1):21-32
Collagens contain large numbers of Gly-Xaa-Yaa peptide repeats that form the characteristic triple helix, where the individual chains fold into a polyproline II helix and three of these helices form a right-handed triple helix. For the proper folding of the triple helix collagens contain trimerization domains. These domains ensure a single starting point for triple helix formation and are also responsible for the chain selection in heterotrimeric collagens. Trimerization domains are non-collagenous domains of very different structures. The size of trimerization domains varies from 35 residues in type IX collagen to around 250 residues for the fibrillar collagens. These domains are not only crucial for biological functions, but they are also attractive tools for generating recombinant collagen fragments of interest as well as for general use in protein engineering and biomaterial design. Here we review the current knowledge of the structure and function of these trimerization domains. 相似文献
984.
Platonova A Koltsova SV Hamet P Grygorczyk R Orlov SN 《Apoptosis : an international journal on programmed cell death》2012,17(5):429-438
Contrasting cell volume behaviours (swelling vs. shrinkage) are considered as criteria to distinguish necrosis from apoptosis.
In this study, we employed a time-lapse, dual-image surface reconstruction technique to assess the volume of single vascular
smooth muscle cells transfected with E1A-adenoviral protein (E1A-VSMC) and undergoing rapid apoptosis in the absence of growth
factors or in the presence of staurosporine. After 30- to 60-min lag-phase, serum-deprived E1A-VSMC volume was increased by
~40%, which preceded maximal increments of caspase-3 activity and chromatin cleavage. Swollen cells underwent rapid apoptotic
collapse, documented by plasma membrane budding, and terminated in 10–15 min by the formation of numerous apoptotic bodies.
Suppression of apoptosis by inhibition of Na+,K+-ATPase and activation of cAMP signalling with ouabain and forskolin, respectively, completely abolished the swelling of serum-deprived
E1A-VSMC. In contrast to serum deprivation, apoptotic collapse of staurosporine-treated E1A-VSMC preceded attenuation of their
volume by ~30%. Neither transient hyposmotic swelling nor isosmtotic shrinkage triggered apoptosis. Our results show that
cell shrinkage can not be considered as ubiquitous hallmark of apoptosis. The involvement of stimulus-specific cell volume
perturbations in initiation and progression of apoptosis in vascular smooth muscle cells should be examined further. 相似文献
985.
Viktor I. Lyamichev Sergei M. Mirkin Maxim D. Frank-Kamenetskii 《Journal of biomolecular structure & dynamics》2013,31(2):275-282
Abstract We have recently shown that a (GA)n · (TC)n tract undergoes a sharp structural transition under superhelical stress (V.I. Lyamichev, S.M. Mirkin and M.D. Frank-Kamenetskii, J. Biomol. Struct. Dyn. 2, 327 (1985)). Unlike the well studied transitions to the cruciform and to the Z form, this novel transition was strongly pH-dependent. We have found the (dG)n · (dC)n insert to undergo a pH-dependent structural transition similar to that of the (GA)n · (TC)n tract. These new data meet our earlier expectations and disagree with the data of D.E. Pulleyblank, D.B. Haniford and A.R. Morgan, Cell 42, 271 (1985). We conclude that a novel DNA structure (the H-form) is typical of homopurine-homopyrimidine mirror repeats (the H palindromes) under superhelical stress and/or acid pH. In the H-form the homopyrimidine strand forms a hairpin while half of the homopurine strand interacts with the hairpin forming a triplex, the other half of the homopurine strand being unstructured (V.I. Lyamichev, S.M. Mirkin and M.D. Frank-Kamenetskii, J. Biomol. Struct. Dyn. 2, 3,667 (1986)). 相似文献
986.
987.
Ilya Ruvinsky Olga Chertkov Xenia V. Borue Sergei I. Agulnik Jeremy J. Gibson-Brown Stephen R. Lyle Lee M. Silver 《Mammalian genome》2002,13(12):675-679
Mutations in the mouse Brachyury (T) gene are characterized by a dominant reduction of tail length and recessive lethality.
Two quantitative trait loci, Brachyury-modifier 1 and 2 (Brm1 and Brm2) are defined by alleles that enhance the short-tail
Brachyury phenotype. Here we report on a genetic analysis of a visible dominant mutation Abnormal feet and tail (Aft) located
in the vicinity of Brm1. Affected animals display kinky tails and syndactyly in the hindlimbs, both likely resulting from
a defect in apoptosis. We observed an unusual genetic incompatibility between Aft and certain genetic backgrounds. We show
that Aft and T are likely to interact genetically, since some double heterozygotes are tailless. In addition to the tail and
hindlimb phenotypes, Aft-bearing mutants display characteristic late-onset skin lesions. We therefore tested for allelism
between Aft and a closely linked recessive mutation rough coat (rc) and found that these two mutations are likely nonallelic.
Our results provide a valuable resource for the study of mammalian skin development and contribute to the genetic analysis
of Brachyury function. 相似文献
988.
Synergy between CD40 ligation and IL-4 on fibroblast proliferation involves IL-4 receptor signaling. 总被引:4,自引:0,他引:4
Sergei P Atamas Irina G Luzina Heqiao Dai Susan G Wilt Barbara White 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(3):1139-1145
Fibrosis can be an undesired consequence of activated cellular immune responses. The purpose of this work was to determine whether CD40 ligation and the pro-fibrotic cytokine IL-4 interact in regulating fibroblast proliferation and collagen production, and, if so, the mechanisms used. This study found that the combination of IL-4 and ligation of CD40 on the fibroblast cell surface had synergistic effects in stimulating fibroblast proliferation. In contrast, CD40 ligation negated the inhibitory effects of IFN-gamma on fibroblast proliferation. Western blotting analyses of fibroblast crude lysates revealed that a potential mechanism of the synergy between CD40 ligation and IL-4 was the phosphorylation of proteins at 130 kDa and, to a lesser degree, at 95, 85, and 75 kDa. Immunoprecipitation-Western blotting experiments showed that phosphorylation levels of IL-4Ralpha, Janus kinase 1, insulin receptor substrate 1, and insulin receptor substrate 2, factors with molecular mass close to the observed 130 kDa major phosphorylation band, increased in response to the combined CD40 ligation and IL-4 action. In contrast, there was no evidence that synergy was mediated by an increased expression of IL-4Ralpha chain, CD40, or the autocrine profibrotic cytokines IL-6 and TGF-beta. These findings suggest that CD40-CD40 ligand contacts between fibroblasts and cells secreting IL-4 may promote the profibrotic effects of IL-4 by affecting signal transduction and reducing the anti-fibrotic effects of IFN-gamma. 相似文献
989.
Ammodesmidae are represented in western Africa by two species of a single genus, Ammodesmus Cook, 1896 (= Cenchrodesmus Cook, 1896, syn. n.). The type-species Ammodesmus granum Cook, 1896 (= Cenchrodesmus volutus Cook, 1896, syn. n.) is redescribed, based on neotype selection, as well as on additional samples, often containing numerous specimens, from Liberia, Guinea and the Ivory Coast. A new species is described from Mount Nimba, Guinea: Ammodesmus nimba
sp. n. 相似文献
990.
Aggregation of amphotericin B (AmB) in an ionic liquid‐rich environment was investigated using circular dichroism (CD) spectroscopy. It was found that nature of the ionic liquids’ anion had a strong impact not only on the aggregation of AmB, but more importantly on the nature of AmB aggregates, as observed in the asymmetry of the exciton couplet of the aggregate in CD spectra. Unique CD signals for AmB aggregates were observed in three different 1‐butyl‐3‐methylimidazolium ionic liquid solutions: [C4‐mim]Br favored the formation of AmB aggregates that were similar to those found in water, whereas [C4‐mim]BF4 and [C4‐mim]NO3 produced AmB aggregates that were different from each other and those found in water. The obtained results suggest that the designer solvent ability of ionic liquids could be expanded to address numerous intermolecular processes. Chirality 25:487‐492, 2013. © 2013 Wiley Periodicals, Inc. 相似文献