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101.
Kendall MM Wardlaw GD Tang CF Bonin AS Liu Y Valentine DL 《Applied and environmental microbiology》2007,73(2):407-414
Methanogenesis in cold marine sediments is a globally important process leading to methane hydrate deposits, cold seeps, physical instability of sediment, and atmospheric methane emissions. We employed a multidisciplinary approach that combined culture-dependent and -independent analyses with geochemical measurements in the sediments of Skan Bay, Alaska (53 degrees N, 167 degrees W), to investigate methanogenesis there. Cultivation-independent analyses of the archaeal community revealed that uncultivated microbes of the kingdoms Euryarchaeota and Crenarchaeota are present at Skan Bay and that methanogens constituted a small proportion of the archaeal community. Methanogens were cultivated from depths of 0 to 60 cm in the sediments, and several strains related to the orders Methanomicrobiales and Methanosarcinales were isolated. Isolates were psychrotolerant marine-adapted strains and included an aceticlastic methanogen, strain AK-6, as well as three strains of CO(2)-reducing methanogens: AK-3, AK7, and AK-8. The phylogenetic positions and physiological characteristics of these strains are described. We propose a new species, Methanogenium boonei, with strain AK-7 as the type strain. 相似文献
102.
103.
Hay BA Abrams B Zumbrunn AY Valentine JJ Warren LC Petras SF Shelly LD Xia A Varghese AH Hawkins JL Van Camp JA Robbins MD Landschulz K Harwood HJ 《Bioorganic & medicinal chemistry letters》2007,17(16):4411-4414
The discovery and efficacy of a series of potent aminopyrrolidineamide-based inhibitors of sterol regulatory element binding protein site-1 protease is described. 相似文献
104.
More than 100 different mutations in the gene encoding copper-zinc superoxide dismutase (SOD1) cause familial forms of amyotrophic lateral sclerosis (ALS)--a fatal neurodegenerative disease in which aggregation of the SOD1 protein is considered to be the primary mode of pathogenesis. Recent results show that these mutations have remarkably diverse and unexpected effects on the structure, activity and native state stability of SOD1. Intriguingly, many mutations seem to have no measurable effect on the biophysical and biochemical properties of SOD1, except for decreasing the net charge of the protein. Thus, it seems likely that different ALS-associated mutations promote SOD1 aggregation by fundamentally distinct mechanisms. Understanding this complexity has implications for drug development and treatment of the disease. 相似文献
105.
Nucci NV Marques BS Bédard S Dogan J Gledhill JM Moorman VR Peterson RW Valentine KG Wand AL Wand AJ 《Journal of biomolecular NMR》2011,50(4):421-430
Comprehensive application of solution NMR spectroscopy to studies of macromolecules remains fundamentally limited by the molecular
rotational correlation time. For proteins, molecules larger than 30 kDa require complex experimental methods, such as TROSY
in conjunction with isotopic labeling schemes that are often expensive and generally reduce the potential information available.
We have developed the reverse micelle encapsulation strategy as an alternative approach. Encapsulation of proteins within
the protective nano-scale water pool of a reverse micelle dissolved in ultra-low viscosity nonpolar solvents overcomes the
slow tumbling problem presented by large proteins. Here, we characterize the contributions from the various components of
the protein-containing reverse micelle system to the rotational correlation time of the encapsulated protein. Importantly,
we demonstrate that the protein encapsulated in the reverse micelle maintains a hydration shell comparable in size to that
seen in bulk solution. Using moderate pressures, encapsulation in ultra-low viscosity propane or ethane can be used to magnify
this advantage. We show that encapsulation in liquid ethane can be used to reduce the tumbling time of the 43 kDa maltose
binding protein from ~23 to ~10 ns. These conditions enable, for example, acquisition of TOCSY-type data resolved on the adjacent
amide NH for the 43 kDa encapsulated maltose binding protein dissolved in liquid ethane, which is typically impossible for
proteins of such size without use of extensive deuteration or the TROSY effect. 相似文献
106.
Sehati S Clement MH Martins J Xu L Longo VD Valentine JS Gralla EB 《Free radical biology & medicine》2011,50(11):1591-1598
Yeast lacking copper-zinc superoxide dismutase (sod1?) have a number of oxygen-dependent defects, including auxotrophies for lysine and methionine and sensitivity to oxygen. Here we report additional defects in metabolic regulation. Under standard growth conditions with glucose as the carbon source, yeast undergo glucose repression in which mitochondrial respiration is deemphasized, energy is mainly derived from glycolysis, and ethanol is produced. When glucose is depleted, the diauxic shift is activated, in which mitochondrial respiration is reemphasized and stress resistance increases. We find that both of these programs are adversely affected by the lack of Sod1p. Key events in the diauxic shift do not occur and sod1? cells do not utilize ethanol and stop growing. The ability to shift to growth on ethanol is gradually lost as time in culture increases. In early stages of culture, sod1? cells consume more oxygen and have more mitochondrial mass than wild-type cells, indicating that glucose repression is not fully activated. These changes are at least partially dependent on the activity of the Hap2,3,4,5 complex, as indicated by CYC1-lacZ reporter assays. These changes may indicate a role for superoxide in metabolic signaling and regulation and/or a role for glucose derepression in defense against oxidative stress. 相似文献
107.
Nina S. Brykova Dmitriy A. Gusarov Irene V. Sokolova Valentine D. Gusarova Tatjana V. Vorobjeva Dmitry I. Bairamashvili 《Process Biochemistry》2011,46(10):2036-2043
It was shown that H1 type histones possess anticancer activity and could be utilized in therapy of acute myeloid leukemia. We developed an experimental pilot-scale technology of the recombinant histone H1.3 variant production. The downstream process includes acidic extraction of the target protein from the culture broth, ion-exchange, reversed-phase and size-exclusion chromatography, and freeze-drying. The accent was made on the reduction of bacterial endotoxin contamination of the active pharmaceutical ingredient. Highly efficient downstream strategy of the target protein depyrogenation is discussed in the paper. The developed technology allows the production of the protein with high yield (approx. 110 g per 1000 L of the culture broth) and of high purity (estimated productivity is 75–100 g/month). The activity and purity of the active pharmaceutical ingredients produced for clinical trials were confirmed by different tests including ultra performance liquid chromatography, size exclusion chromatography, ELISA, SDS–PAGE, gel-clot LAL-test. Clinical trials were started in the Russian Federation. 相似文献
108.
Ait-Mohamed O Battisti V Joliot V Fritsch L Pontis J Medjkane S Redeuilh C Lamouri A Fahy C Rholam M Atmani D Ait-Si-Ali S 《PloS one》2011,6(9):e24537
Plants are an invaluable source of potential new anti-cancer drugs. Here, we investigated the cytotoxic activity of the acetonic extract of Buxus sempervirens on five breast cancer cell lines, MCF7, MCF10CA1a and T47D, three aggressive triple positive breast cancer cell lines, and BT-20 and MDA-MB-435, which are triple negative breast cancer cell lines. As a control, MCF10A, a spontaneously immortalized but non-tumoral cell line has been used. The acetonic extract of Buxus sempervirens showed cytotoxic activity towards all the five studied breast cancer cell lines with an IC(50) ranging from 7.74 μg/ml to 12.5 μg/ml. Most importantly, the plant extract was less toxic towards MCF10A with an IC(50) of 19.24 μg/ml. Fluorescence-activated cell sorting (FACS) analysis showed that the plant extract induced cell death and cell cycle arrest in G0/G1 phase in MCF7, T47D, MCF10CA1a and BT-20 cell lines, concomitant to cyclin D1 downregulation. Application of MCF7 and MCF10CA1a respective IC(50) did not show such effects on the control cell line MCF10A. Propidium iodide/Annexin V double staining revealed a pre-apoptotic cell population with extract-treated MCF10CA1a, T47D and BT-20 cells. Transmission electron microscopy analyses indicated the occurrence of autophagy in MCF7 and MCF10CA1a cell lines. Immunofluorescence and Western blot assays confirmed the processing of microtubule-associated protein LC3 in the treated cancer cells. Moreover, we have demonstrated the upregulation of Beclin-1 in these cell lines and downregulation of Survivin and p21. Also, Caspase-3 detection in treated BT-20 and T47D confirmed the occurrence of apoptosis in these cells. Our findings indicate that Buxus sempervirens extract exhibit promising anti-cancer activity by triggering both autophagic cell death and apoptosis, suggesting that this plant may contain potential anti-cancer agents for single or combinatory cancer therapy against breast cancer. 相似文献
109.
Occurrence and diversity of mesophilic Shewanella strains isolated from the North-West Pacific Ocean 总被引:1,自引:0,他引:1
Ivanova EP Sawabe T Zhukova NV Gorshkova NM Nedashkovskaya OI Hayashi K Frolova GM Sergeev AF Pavel KG Mikhailov VV Nicolau DV 《Systematic and applied microbiology》2003,26(2):293-301
Although bacteria of the genus Shewanella belong to one of the readily cultivable groups of "Gammaproteobacteria", little is known about the occurrence and abundance of these microorganisms in the marine ecosystem. Studies revealed that of 654 isolates obtained from marine invertebrates (ophiuroid Amphiopholis kochii, sipuncula Phascolosoma japonicum, and holothurian Apostichopus japonicus, Cucumaria japonica), seawater and sediments of the North-West Pacific Ocean (i.e. the Sea of Japan and Iturup Is, Kurile Islands), 10.7% belonged to the genus Shewanella. The proportion of viable Shewanella species varied from 4% to 20% depending on the source of isolation. From the isolation study, representative strains of different phenotypes (from seventy presumptive Shewanella strains) were selected for detailed characterization using phenotypic, chemotaxonomic, and phylogenetic testing. 16S rDNA sequence-based phylogenetic analysis confirmed the results of tentative identification and placed the majority of these strains within only a few species of the genus Shewanella with 98-99% of 16S rDNA sequences identity mainly with S. japonica and S. colwelliana, suggesting that the strains studied might belong to these species. Numerically dominant strains of S. japonica were metabolically active and produced proteinases (gelatinases, caseinases), lipases, amylases, agarases, and alginases. Shewanella strains studied demonstrated weak antimicrobial and antifungal activities that might be an indication of their passive role in the colonization on living and non-living surfaces. 相似文献
110.
Autotrophic picoplankton in southern Lake Baikal: abundance, growth and grazing mortality during summer 总被引:5,自引:0,他引:5
Nagata Toshi; Takai Kenji; Kawanobe Kyoko; Kim Dong-Sup; Nakazato Ryoji; Guselnikova Nina; Bondarenko Nina; Mologawaya Oliga; Kostrnova Tatyana; Drucker Valentine; Satoh Yasuhiro; Watanabe Yasunori 《Journal of plankton research》1994,16(8):945-959
Autotrophic picoplankton were highly abundant during the thermalstratification period in late July in the pelagic area (waterdepth 5001300 m) of southern Lake Baikal; maximum numberswere 2 x 106 cells ml1 in the euphotic zone ({small tilde}15m). Unicellular cyanobacteria generally dominated the picoplanktoncommunity, although unidentified picoplankton that fluorescedred under blue excitation were also abundant (maximum numbers4 x 105 cells ml1) and contributed up to {small tilde}40%of the total autotrophic picoplankton on occasions. Carbon andnitrogen biomasses of autotrophic picoplankton estimated byconversion from biovolumes were 1484 µg C l1and 3.621 µg N l1. These were comparableto or exceeded the biomass of heterotrophic bacteria. Autotropicpicoplankton and bacteria accounted for as much as 33% of paniculateorganic carbon and 81% of nitrogen in the euphotic zone. Measurementsof the photosynthetic uptake of [l4C]bicarbonate and the growthof picoplankton in diluted or size-fractionated waters revealedthat 80% of total primary production was due to picoplankton,and that much of this production was consumed by grazers inthe <20 µ.m cell-size category. These results suggestthat picoplankton-protozoan trophic coupling is important inthe pelagic food web and biogeochemical cycling of Lake Baikalduring summer. 相似文献