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1.
The activity of the transposase of bacteriophage Mu is unstable, requiring the protein to be synthesized throughout the lytic cycle (Pato and Reich, 1982). Using Western blot analysis, we analysed the stability of the transposase protein during the lytic cycle and found that it, too, is unstable. The instability of the protein is observed both in the presence and the absence of Mu DNA replication, and is independent of other Mu-encoded proteins and the transposase binding sites at the Mu genome ends. Stability of the protein is enhanced in host strains mutated at the hfl locus; however, stability of the transposase activity is not enhanced in these strains, suggesting that functional inactivation of the protein is not simply a result of its proteolysis. 相似文献
2.
J. Teixeira M. H. Gonçalves F. M. Gama P. Moradas-Ferreira M. Mota 《Biotechnology letters》1989,11(8):579-582
Summary Cell walls from aKluyveromyces marxianus either non flocculent or flocculent strain were isolated and analysed for protein, carbohydrates and phosphate content. Alkaline extract of proteins were analysed by SDS-PAGE. The results revealed a higher protein content in the cell walls from the flocculent strain. Electrophoresis of the cell wall proteins of the flocculent strain showed an extra peptide with an apparent molecular weight of 37 KDa which is absent fom non-flocculent cells. The involvement of this protein in cell adhesion during flocculation is discussed. 相似文献
3.
M A Gama Sosa J C Hall K E Schneider G C Lukaszewicz R M Ruprecht 《Biochemical and biophysical research communications》1989,161(1):134-142
Supercoiled pHXBc2 DNA (containing the genome of the human immunodeficiency virus type 1 and human sequences) migrated more slowly than linear DNA in native and ethidium bromide agarose gel electrophoresis at 4.5 volts/cm, suggesting the presence of unusual DNA structures. S1 nuclease analysis of pHXBc2 revealed two S1 hypersensitive sites. Site I was located within a 25 bp direct repeat in host DNA 0.6 kB upstream from the 5' LTR. Site II was mapped 0.2 kB upstream from the vif gene start site. Sequence analysis showed that Site I sequences could assume different unusual DNA structures, whereas sequences at Site II could assume either slipped or H-DNA forms. Unusual DNA structures in host DNA may be associated with active chromatin regions and may favor proviral integration. 相似文献
4.
Characterization of amber mutations in bacteriophage Mu transposase: a functional analysis of the protein 总被引:7,自引:3,他引:4
We have characterized a series of amber mutations in the A gene of bacteriophage Mu encoding the phage transposase. We tested different activities of these mutant proteins either in a sup0 strain or in different sup bacteria. In conjunction with the results described in the accompanying paper by Bétermier et al. (1989) we find that the C-terminus of the protein is not absolutely essential for global transposase function, but is essential for phage growth. Specific binding to Mu ends is defined by a more central domain. Our results also reinforce the previous findings (Bétermier et al., 1987) that more than one protein may be specified by the A gene. 相似文献
5.
A A da Gama 《Journal of theoretical biology》1990,142(2):251-260
A model for the through-bond electronic interaction between electron donor and acceptor in proteins is developed. We use a one-electron Hamiltonian, write the Dyson's equation in site representation and solve it by using a Green's function formalism with some renormalization ideas. An expression for Tab which describes the exponential decay with distance bond per bond is obtained. Covalent, non-covalent and convergent pathways are considered and no periodic approximation is needed. 相似文献
6.
Yutaka Ishigami Yasuo Gama Yoh Sano Siegmund Lang Fritz Wagner 《Biotechnology letters》1994,16(6):593-598
Summary Glucose lipid of notable surfactant properties was produced by using hydrocarbon assimilating bacterium of the bacterial strain MM1. Its surface active properties were notable in spite of ,-hydrophilic and bulky molecule. The critical micelle concentration (cmc) was small (0.165 M); surface and interfacial tension for hexadecane at 0.1 % (pH 7.35) solution, 24.6 and 13.3 mN/m, respectively. The emulsifying action was excellent and comparable to those of rhamnolipids. The micelle has the outer radius. 28.5 Å and inner core, 6.7 Å on the basis of the concentric spherical shell model by means of the small angle X-ray solution scattering measurement.Dedicated to Professor Fritz Wagner on the occasion of his 65th birthday. 相似文献
7.
Mafalda C. O. Figueiredo Susana A. L. Lobo Sara H. Sousa Fábio P. Pereira Judy D. Wall Lígia S. Nobre Lígia M. Saraiva 《Journal of bacteriology》2013,195(11):2684-2690
Desulfovibrio species are Gram-negative anaerobic sulfate-reducing bacteria that colonize the human gut. Recently, Desulfovibrio spp. have been implicated in gastrointestinal diseases and shown to stimulate the epithelial immune response, leading to increased production of inflammatory cytokines by macrophages. Activated macrophages are key cells of the immune system that impose nitrosative stress during phagocytosis. Hence, we have analyzed the in vitro and in vivo responses of Desulfovibrio vulgaris Hildenborough to nitric oxide (NO) and the role of the hybrid cluster proteins (HCP1 and HCP2) and rubredoxin oxygen oxidoreductases (ROO1 and ROO2) in NO protection. Among the four genes, hcp2 was the gene most highly induced by NO, and the hcp2 transposon mutant exhibited the lowest viability under conditions of NO stress. Studies in murine macrophages revealed that D. vulgaris survives incubation with these phagocytes and triggers NO production at levels similar to those stimulated by the cytokine gamma interferon (IFN-γ). Furthermore, D. vulgaris
hcp and roo mutants exhibited reduced viability when incubated with macrophages, revealing that these gene products contribute to the survival of D. vulgaris during macrophage infection. 相似文献
8.
Mathias Ahii Chia Ana Teresa Lombardi Maria da Graça Gama Melão 《Phycological Research》2013,61(4):286-291
Quantification of the calorific content of microalgae is critical in studies of energy flow, trophic partitioning, plant/herbivore interactions in aquaculture and biomass production for biofuels. We investigated the calorific value and biochemical composition of Chlorella vulgaris at different phosphorus (P) concentrations (6.0 × 10?7, 2.3 × 10?6 and 2.3 × 10?4 mol L?1 P). As expected, the control (2.3 × 10?4 mol L?1 P) supported better growth than P limited treatments. Biomolecules like total carbohydrates and lipids accumulated under P limitation, which significantly correlated with high calorific values. Lipid class composition showed that triacylglycerols were the most accumulated under P limited conditions. The calorific value reported under control conditions (13.78 kJ g?1) was less than those obtained under P limitation (30.47–33.07 kJ g?1). The highest calorific value with less growth retardation was obtained at 2.3 × 10?6 mol L?1 P. 相似文献
9.
Timothy W. Yu Maria H. Chahrour Michael E. Coulter Sarn Jiralerspong Kazuko Okamura-Ikeda Bulent Ataman Klaus Schmitz-Abe David A. Harmin Mazhar Adli Athar N. Malik Alissa M. D’Gama Elaine T. Lim Stephan J. Sanders Ganesh H. Mochida Jennifer N. Partlow Christine M. Sunu Jillian M. Felie Jacqueline Rodriguez Christopher A. Walsh 《Neuron》2013,77(2):259-273
10.
Photosynthetic characteristics and quality of five passion fruit varieties under field conditions 总被引:1,自引:0,他引:1
Vinícius Novo Gama Joilton Tavares Cunha Inorbet de Melo Lima Marcos Antonio Bacarin Diolina Moura Silva 《Acta Physiologiae Plantarum》2013,35(3):941-948
Due to photosynthetic mechanisms respond very quickly to most stressors and due to strong concerns regarding the impact of climate change on future plant productivity, the purpose of this study was to perform a comparative analysis of in vivo photosynthetic efficiencies and fruit quality of five cultivars of passion fruit (Passiflora edulis Sims. f. flavicarpa Degener). The experiments were conducted in the northern region of Espírito Santo State using cultivars FB 200, FB 300, BRS Gigante Amarelo, BRS Sol do Cerrado, and BRS Ouro Vermelho. Analyses were performed 6 months after planting, when the plants were beginning reproduction and were repeated two times during the next 4 months until fruit ripening. Chlorophyll a fluorescence transient, total chlorophyll content, and gas exchange were measured in the leaves. Physical and chemical fruit attributes were also assessed. The lowest fluorescence rates were identified in the FB 300, BRS Sol do Cerrado, and BRS Ouro Vermelho cultivars, which exhibited better capacities for quinone A (QA) reoxidation and better electron transfer efficiencies from Photosystem II to Photosystem I acceptors. Better photochemical performances (PItotal) and CO2 assimilations (A) resulted in higher fruit pulp yields, demonstrating the superior quality of the FB 300, BRS Sol do Cerrado, and BRS Ouro Vermelho cultivars. 相似文献