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排序方式: 共有444条查询结果,搜索用时 15 毫秒
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Studies with cyanidium caldarium,an anomalously pigmented chlorophyte 总被引:12,自引:0,他引:12
Mary Belle Allen 《Archives of microbiology》1959,32(3):270-277
Summary
Cyanidium caldarium, an alga found in acid hot springs troughout the world, has a morphology and developmental history resembling those of Chlorella, but contains C-phycocyanin and no chlorophyll other than chlorophyll a. The reasons for considering it to be a member of the Chlorophyta are reviewed.
Cyanidium is also remarkable for its thermal and acid tolerance. It grows readily in the dark on sugar media. However, light is required for the formation of chlorophyll and phycocyanin except in occasional variant cells which can form limited amounts of these pigments in the dark. Light-grown Cyanidium carries out normal green plant photosynthesis but resembles the red and some of the blue-green algae in that chlorophyll-absorbed light is used with lower efficiency than that absorbed by phycocyanin.The possible significance of the unusual pigmentation of Cyanidium is discussed.Contribution no.23 from the Laboratory of Comparative Physiology and Morphology of The Kaiser Foundation. 相似文献
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Saccharification of Complex Cellulosic Substrates by the Cellulase System from Clostridium thermocellum 总被引:37,自引:15,他引:22
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Eric A. Johnson Mitsuji Sakajoh Geoffrey Halliwell Ashwin Madia Arnold L. Demain 《Applied microbiology》1982,43(5):1125-1132
True cellulase activity has been demonstrated in cell-free preparations from the thermophilic anaerobe Clostridium thermocellum. Such activity depends upon the presence of Ca2+ and a thiol-reducing agent of which dithiothreitol is the most promising. Under these conditions, native (cotton) and derived forms of cellulose (Avicel and filter paper) were all extensively solubilized at rates comparable with cellulase from Trichoderma reesei. Maximum activity of the Clostridium cellulase was displayed at 70°C and at pH 5.7 and 6.1 on Avicel and carboxymethylcellulose, respectively. In the absence of substrate at temperatures up to 70°C, carboxymethylcellulase was much more unstable than the Avicel-hydrolyzing activity. 相似文献
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Exogenous beta casein, previously phosphorylated in vitro by protein kinase A and casein kinase II, was microinjected into Xenopus oocytes to monitor in vivo protein phosphatase activities. Phosphatase activities were 1.6 and 3.4 fmol/min/oocyte, respectively, for beta casein phosphorylated by casein kinase II and beta casein phosphorylated by protein kinase A. Progesterone induced an early decrease (35% after 10 min) in phosphatase activity restricted to the protein kinase A sites of beta casein. 相似文献
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Thorsten Pfirrmann Ashwin Lokapally Claes Andréasson Per Ljungdahl Thomas Hollemann 《PloS one》2013,8(6)
Modern biology research requires simple techniques for efficient and restriction site-independent modification of genetic material. Classical cloning and mutagenesis strategies are limited by their dependency on restriction sites and the use of complementary primer pairs. Here, we describe the Single Oligonucleotide Mutagenesis and Cloning Approach (SOMA) that is independent of restriction sites and only requires a single mutagenic oligonucleotide to modify a plasmid. We demonstrate the broad application spectrum of SOMA with three examples. First, we present a novel plasmid that in a standardized and rapid fashion can be used as a template for SOMA to generate GFP-reporters. We successfully use such a reporter to assess the in vivo knock-down quality of morpholinos in Xenopus laevis embryos. In a second example, we show how to use a SOMA-based protocol for restriction-site independent cloning to generate chimeric proteins by domain swapping between the two human hRMD5a and hRMD5b isoforms. Last, we show that SOMA simplifies the generation of randomized single-site mutagenized gene libraries. As an example we random-mutagenize a single codon affecting the catalytic activity of the yeast Ssy5 endoprotease and identify a spectrum of tolerated and non-tolerated substitutions. Thus, SOMA represents a highly efficient alternative to classical cloning and mutagenesis strategies. 相似文献
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Mohanan Manoj Vadakkenchery Pushpanathan Anunanthini Padmanabhan Sarath Sasikumar Thelakat Jayanarayanan Ashwin Narayan Selvarajan Dharshini Ramalingam Sathishkumar Ram Bakshi Chinnaswamy Appunu 《Journal of plant research》2021,134(5):1083-1094
Journal of Plant Research - The glyoxalase pathway is a check point to monitor the elevation of methylglyoxal (MG) level in plants and is mediated by glyoxalase I (Gly I) and glyoxalase II (Gly II)... 相似文献
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France Bruck Ludovic Belle Chantal Lechanteur Laurence de Leval Muriel Hannon Sophie Dubois Emilie Castermans Stephanie Humblet-Baron Souad Rahmouni Yves Beguin Alexandra Briquet Frédéric Baron 《Cytotherapy》2013,15(3):267-279
Background aimsGraft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation caused by donor T cells reacting against host tissues. Previous studies have suggested that mesenchymal stromal cells (MSCs) could exert potent immunosuppressive effects.MethodsThe ability of human bone marrow derived MSCs to prevent xenogeneic GVHD in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice and in NOD/SCID/interleukin-2Rγ(null) (NSG) mice transplanted with human peripheral blood mononuclear cells (PBMCs) was assessed.ResultsInjection of 200 × 106 human PBMCs intraperitoneally (IP) into sub-lethally (3.0 Gy) irradiated NOD/SCID mice also given anti-asialo GM1 antibodies IP 1 day prior and 8 days after transplantation induced lethal xenogeneic GVHD in all tested mice. Co-injection of 2 × 106 MSCs IP on day 0 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs. Similarly, injection of 30 × 106 human PBMCs IP into sub-lethally (2.5 Gy) irradiated NSG mice induced a lethal xenogeneic GVHD in all tested mice. Injection of 3 × 106 MSCs IP on days 0, 7, 14 and 21 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs.ConclusionsInjection of MSCs did not prevent xenogeneic GVHD in these two humanized mice models. 相似文献