Nostoc
Mostrando 25-36 de 132 artigos, teses e dissertações.
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25. Transcriptional Regulation of Nostoc Hydrogenases: Effects of Oxygen, Hydrogen, and Nickel
The transcription of structural genes encoding two hydrogenases in N2-fixing cultures of the cyanobacteria Nostoc muscorum and Nostoc sp. strain PCC 73102 were examined by reverse transcription-PCR. A low level of oxygen and addition of nickel induce higher transcript levels of both hydrogenases, whereas molecular hydrogen has a positive effect on the transc
American Society for Microbiology.
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26. A New UV-A/B Protecting Pigment in the Terrestrial Cyanobacterium Nostoc commune1
A new ultraviolet (UV)-A/B absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium Nostoc commune is described. The pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar UV radiation but only in low concentrations in laboratory cultures illuminated by artificial light without
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27. Characteristics of Hormogonia Formation by Symbiotic Nostoc spp. in Response to the Presence of Anthoceros punctatus or Its Extracellular Products
Nostocacean cyanobacteria typically produce gliding filaments termed hormogonia at a low frequency as part of their life cycle. We report here that all Nostoc spp. competent in establishing a symbiotic association with the hornwort Anthoceros punctatus formed hormogonial filaments at a high frequency in the presence of A. punctatus. The hormogonia-inducing a
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28. Physiological sources of reductant for nitrogen fixation activity in Nostoc sp. strain UCD 7801 in symbiotic association with Anthoceros punctatus.
Pure cultures of the symbiotic cyanobacterium-bryophyte association with Anthoceros punctatus were reconstituted by using Nostoc sp. strain UCD 7801 or its 3-(3,4-dichlorophenol)-1,1-dimethylurea (DCMU)-resistant mutant strain, UCD 218. The cultures were grown under high light intensity with CO2 as the sole carbon source and then incubated in the dark to dep
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29. Formation of hybrid phycobilisomes by association of phycobiliproteins from Nostoc and Fremyella
Formation of phycobilisomes has been accomplished in vitro from isolated phycobiliprotein fractions obtained from the same blue-green alga (intrageneric) and from different blue-green algae (intergeneric). Phycobilisomes, which are supra-molecular complexes of phycobiliproteins, serve as major light-harvesting antennae for photosynthesis in blue-green and re
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30. Polysome turnover in immobilized cells of Nostoc commune (cyanobacteria) exposed to water stress.
Water stress induced changes in the polysome content of immobilized cells of the desiccation-tolerant cyanobacterium Nostoc commune UTEX 584. Cells maintained an intact protein synthesis complex during 2 h of drying at -99.5 MPa. Polysomes were not recovered from cells subjected to extended periods of desiccation.
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31. Strain characterization and classification of oxyphotobacteria in clone cultures on the basis of 16S rRNA sequences from the variable regions V6, V7, and V8.
A major problem in development of a polyphasic taxonomy is that the identification of oxyphotobacterial strains (cyanobacteria and prochlorophytes) in culture collections may be incorrect. We have therefore developed a diagnostic system using the DNA sequence polymorphism in the 16S rRNA regions V6 to V8 for individual strain characterization and identificat
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32. Variation in Phospholipid Ester-Linked Fatty Acids and Carotenoids of Desiccated Nostoc commune (Cyanobacteria) from Different Geographic Locations
Profiles of phospholipid fatty acids and carotenoids in desiccated Nostoc commune (cyanobacteria) collected from China, Federal Republic of Germany, and Antarctica and in axenic cultures of the desiccation-tolerant strains N. commune UTEX 584 and Hydrocoleum strain GOEI were analyzed. The phospholipid fatty acid contents of the three samples of desiccated No
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33. N-Terminus Conservation in the Terminal Pigment of Phycobilisomes from a Prokaryotic and Eukaryotic Alga 1
High molecular weight polypeptides from phycobilisomes, believed to be involved in facilitating the energy flow from phycobilisomes to thylakoids, are conserved in the prokaryote Nostoc sp. and the eukaryote Porphyridium cruentum. Partial N-terminal sequence analysis of the phycobilisome-polypeptides of Nostoc (94 kilodalton) and Porphyridium (92 kilodalton)
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34. Unusual Water Flux in the Extracellular Polysaccharide of the Cyanobacterium Nostoc commune
The speed of water uptake by desiccated Nostoc commune was found to depend upon the duration of desiccation. The rehydration of desiccated colonies led to marked, time-dependent changes in structure and ultrastructure and fluctuations in the composition of the transcriptome. Physical evaporative water loss is an active process that was influenced by inhibito
American Society for Microbiology.
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35. GlbN (cyanoglobin) is a peripheral membrane protein that is restricted to certain Nostoc spp.
The glbN gene of Nostoc commune UTEX 584 is juxtaposed to nifU and nifH, and it encodes a 12-kDa monomeric hemoglobin that binds oxygen with high affinity. In N. commune UTEX 584, maximum accumulation of GlbN occurred in both the heterocysts and vegetative cells of nitrogen-fixing cultures when the rate of oxygen evolution was repressed to less than 25 micro
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36. Regulatory effect of hydrogen on nitrogenase activity of the blue-green alga (cyanobacterium) Nostoc muscorum.
Preincubation of the blue-green alga (cyanobacterium) Nostoc muscorum under an atmosphere of argon plus acetylene in the light led to a greater than fourfold increase of light-induced hydrogen evolution and to a 50% increase of acetylene reduction, as compared to cells that had not been preconditioned. The basic and the increased hydrogen evolution were both