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101.
Hutterer A Berdnik D Wirtz-Peitz F Zigman M Schleiffer A Knoblich JA 《Developmental cell》2006,11(2):147-157
The protein kinase Aurora-A is required for centrosome maturation, spindle assembly, and asymmetric protein localization during mitosis. Here, we describe the identification of Bora, a conserved protein that is required for the activation of Aurora-A at the onset of mitosis. In the Drosophila peripheral nervous system, bora mutants have defects during asymmetric cell division identical to those observed in aurora-A. Furthermore, overexpression of bora can rescue defects caused by mutations in aurora-A. Bora is conserved in vertebrates, and both Drosophila and human Bora can bind to Aurora-A and activate the kinase in vitro. In interphase cells, Bora is a nuclear protein, but upon entry into mitosis, Bora is excluded from the nucleus and translocates into the cytoplasm in a Cdc2-dependent manner. We propose a model in which activation of Cdc2 initiates the release of Bora into the cytoplasm where it can bind and activate Aurora-A. 相似文献
102.
Hemme CL Mouttaki H Lee YJ Zhang G Goodwin L Lucas S Copeland A Lapidus A Glavina del Rio T Tice H Saunders E Brettin T Detter JC Han CS Pitluck S Land ML Hauser LJ Kyrpides N Mikhailova N He Z Wu L Van Nostrand JD Henrissat B He Q Lawson PA Tanner RS Lynd LR Wiegel J Fields MW Arkin AP Schadt CW Stevenson BS McInerney MJ Yang Y Dong H Xing D Ren N Wang A Huhnke RL Mielenz JR Ding SY Himmel ME Taghavi S van der Lelie D Rubin EM Zhou J 《Journal of bacteriology》2010,192(24):6494-6496
Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial systems biology. 相似文献
103.
Juergen Geist 《Hydrobiologia》2010,644(1):69-88
Freshwater pearl mussels (Margartifera margaritifera L.) are among the most critically threatened freshwater bivalves worldwide. The pearl mussel simultaneously fulfils criteria
of indicator, flagship, keystone and umbrella species and can thus be considered an ideal target species for the process conservation
of aquatic ecosystem functioning. The development of conservation strategies for freshwater pearl mussels and for other bivalve
species faces many challenges, including the selection of priority populations for conservation and strategic decisions on
habitat restoration and/or captive breeding. This article summarises the current information about the species’ systematics
and phylogeny, its distribution and status as well as about its life history strategy and genetic population structure. Based
on this information, integrative conservation strategies for freshwater mollusc species which combine genetic and ecological
information are discussed. Holistic conservation strategies for pearl mussels require the integration of Conservation Genetics
and Conservation Ecology actions at various spatial scales, from the individual and population level to global biodiversity
conservation strategies. The availability of high resolution genetic markers for the species and the knowledge of the critical
stages in the life cycle, particularly of the most sensitive post-parasitic phase, are important prerequisites for conservation.
Effective adaptive conservation management also requires an evaluation of previous actions and management decisions. As with
other freshwater bivalves, an integrative conservation approach that identifies and sustains ecological processes and evolutionary
lineages is urgently needed to protect and manage freshwater pearl mussel diversity. Such research is important for the conservation
of free-living populations, as well as for artificial culturing and breeding techniques, which have recently been or which
are currently being established for freshwater pearl mussels in several countries. 相似文献
104.
In vivo imaging reveals dendritic targeting of laminated afferents by zebrafish retinal ganglion cells 总被引:3,自引:0,他引:3
Mumm JS Williams PR Godinho L Koerber A Pittman AJ Roeser T Chien CB Baier H Wong RO 《Neuron》2006,52(4):609-621
Targeting of axons and dendrites to particular synaptic laminae is an important mechanism by which precise patterns of neuronal connectivity are established. Although axons target specific laminae during development, dendritic lamination has been thought to occur largely by pruning of inappropriately placed arbors. We discovered by in vivo time-lapse imaging that retinal ganglion cell (RGC) dendrites in zebrafish show growth patterns implicating dendritic targeting as a mechanism for contacting appropriate synaptic partners. Populations of RGCs labeled in transgenic animals establish distinct dendritic strata sequentially, predominantly from the inner to outer retina. Imaging individual cells over successive days confirmed that multistratified RGCs generate strata sequentially, each arbor elaborating within a specific lamina. Simultaneous imaging of RGCs and subpopulations of presynaptic amacrine interneurons revealed that RGC dendrites appear to target amacrine plexuses that had already laminated. Dendritic targeting of prepatterned afferents may thus be a novel mechanism for establishing proper synaptic connectivity. 相似文献
105.
106.
107.
Zhao W Weber C Zhang CL Romanek CS King GM Mills G Sokolova T Wiegel J 《Extremophiles : life under extreme conditions》2006,10(4):337-345
A novel thermophilic, alkali-tolerant, and CO-tolerant strain JW/WZ-YB58T was isolated from green mat samples obtained from the Zarvarzin II hot spring in the Uzon Caldera, Kamchatka (Far East Russia). Cells were Gram-type and Gram stain-positive, strictly aerobic, 0.7–0.8 μm in width and 5.5–12 μm in length and produced terminal spherical spores of 1.2–1.6 μm in diameter with the mother cell swelling around 2 μm in diameter (drumstick-type morphology). Cells grew optimally at pH25°C 8.2–8.4 and temperature 50–52°C and tolerated maximally 6% (w/v) NaCl. They were strict heterotrophs and could not use either CO or CO2 (both with or without H2) as sole carbon source, but tolerated up to 90% (v/v) CO in the headspace. The isolate grew on various complex substrates such as yeast extract, on carbohydrates, and organic acids, which included starch, d-galactose, d-mannose, glutamate, fumarate and acetate. Catalase reaction was negative. The membrane polar lipids were dominated by branched saturated fatty acids, which included iso-15:0 (24.5%), anteiso-15:0 (18.3%), iso-16:0 (9.9%), iso-17:0 (17.5%) and anteiso-17:0 (9.7%) as major constituents. The DNA G+C content of the strain is 45 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain JW/WZ-YB58T is distantly (<93% similarity) related to members of Bacillaceae. On the basis of 16S rRNA gene sequence, physiological and phenotypic characteristics, the isolate JW/WZ-YB58T (ATCC BAA-1258; DSM 17740) is proposed to be the type strain for the type species of the new taxa within the family Bacillaceae, Thermalkalibacillus uzoniensis gen. nov. sp. nov. The Genbank accession number for the 16S rRNA gene sequence is DQ221694.The Genbank accession number for the 16S rRNA gene sequence of strain JW/WZ-YB58T is DQ221694. 相似文献
108.
Walker K Pakhomova ON Kolb J Schoenbach KS Stuck BE Murphy MR Pakhomov AG 《Bioelectromagnetics》2006,27(3):221-225
The study explored the effect of ambient oxygen on mammalian cell survival after exposure to 10 ns duration, high voltage electrical pulses (nsEP, 80-90 or 120-130 kV/cm; 200-400 pulses per exposure). Cell samples were equilibrated with pure nitrogen, atmospheric air, or pure oxygen prior to the nsEP treatment and were returned to the incubator (air + 5% CO2) shortly after the exposure. The experiments established that survival of hypoxic Jurkat and U937 cells exceeded that of air-equilibrated controls about twofold (P < .01). Conversely, saturation of the medium with oxygen prior to exposure decreased Jurkat cell survival about 1.5 times, P < .01. Attenuation of the cytotoxic effect under hypoxic conditions resembled a well-known effect of oxygen on cell killing by sparsely ionizing radiations and may be indicative of the similarity of underlying cell damage mechanisms. 相似文献
109.
Modeling and experimental studies have shown that pulsed electric fields of nanosecond duration and megavolt per meter amplitude affect subcellular structures but do not lead to the formation of large pores in the outer membrane. This "intracellular electromanipulation" requires the use of pulse generators which provide extremely high power but low energy pulses. In this study, we describe the concept of the required pulsed power sources, their design, operation, and the necessary diagnostics. Two types of pulse generators based on the Blumlein line principle have been developed and are described here. One system is designed to treat a large number of cells in cuvettes holding volumes from 0.1 to 0.8 ml. Pulses of up to 40 kV amplitude, with a duration of 10 ns and a rise time close to 1 ns can be applied to the cuvette. For an electrode gap of 1 mm this voltage corresponds to an average electric field of 40 MV/m. The second system allows for real time observation of individual cells under a microscope. It generates pulses of 10-300 ns duration with a rise time of 3.5 ns and voltage amplitudes up to 1 kV. Connected to a microreactor with an electrode gap of 100 microm, electric fields up to 10 MV/m are applied. 相似文献
110.