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171.
Engineered protein libraries, defined here as a collection of different mutant variants of a single specific protein, are intentionally designed to be rich in molecular diversity and can span ranges from as little as 400 different variants to greater than 10(12) members per library. The goal of engineering libraries is to generate new protein variants, identified upon screening, that possess desired novel properties. Exploitation of the natural organization of the genetic code has led to 'focused' libraries that are lower in overall complexity yet biased towards variants with preferred biophysical properties. An emerging trend, in which computational algorithms are blended with in vivo screens, is also leading towards greater and more rapid success in the field of protein design. 相似文献
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173.
Ausmees N Wahlstedt H Bagchi S Elliot MA Buttner MJ Flärdh K 《Molecular microbiology》2007,65(6):1458-1473
Sporulation in aerial hyphae of Streptomyces coelicolor involves profound changes in regulation of fundamental morphogenetic and cell cycle processes to convert the filamentous and multinucleoid cells to small unigenomic spores. Here, a novel sporulation locus consisting of smeA (encoding a small putative membrane protein) and sffA (encoding a SpoIIIE/FtsK-family protein) is characterized. Deletion of smeA-sffA gave rise to pleiotropic effects on spore maturation, and influenced the segregation of chromosomes and placement of septa during sporulation. Both smeA and sffA were expressed specifically in apical cells of sporogenic aerial hyphae simultaneously with or slightly after Z-ring assembly. The presence of smeA-like genes in streptomycete chromosomes, plasmids and transposons, often paired with a gene for a SpoIIIE/FtsK- or Tra-like protein, indicates that SmeA and SffA functions might be related to DNA transfer. During spore development SffA accumulated specifically at sporulation septa where it colocalized with FtsK. However, sffA did not show redundancy with ftsK, and SffA function appeared distinct from the DNA translocase activity displayed by FtsK during closure of sporulation septa. The septal localization of SffA was dependent on SmeA, suggesting that SmeA may act as an assembly factor for SffA and possibly other proteins required during spore maturation. 相似文献
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175.
Zhao T Zhou X Szabó N Leitges M Alvarez-Bolado G 《Genesis (New York, N.Y. : 2000)》2007,45(12):781-787
We have knocked-in Cre-IRES-EGFP in the Foxb1 locus by homologous recombination in embryonic stem cells. We removed the PGK-neo cassette (which was flanked by FRT sequences) by crossing with the FLPeR deleter mouse. The Foxb1(Cre) line showed Cre recombinase activity as well as EGFP fluorescence reproducing Foxb1 expression accurately. By crossing Foxb1(Cre) mice with the ROSA26R and Z/AP mouse reporter lines we have been able to trace the lineage of Foxb1-expressing cells. Early transient expression of Foxb1 in the paraxial mesoderm translates into labeling of the somites. In the central nervous system (CNS), the Foxb1 lineage includes the thalamus and mammillary body (hypothalamus), brainstem, and the ventral spinal cord and floor plate. 相似文献
176.
Álvaro Rodríguez-Peña Ana C. Gonzalez-Franco Jared Hernández-Huerta Nora A. Salas-Salazar Dámaris L. Ojeda-Barrios Esteban Sánchez Loreto Robles-Hernández 《Phyton》2022,91(7):1341-1351
Antibiotics are widely used in fire blight management programs, yet there are no studies that demonstrate the evaluation of their efficacy in Mexico. Therefore, the present study was conducted to investigate the effects of the active ingredients in five commercial products (Kasumin® 2L, Agrygent Plus®, Agricultural Terramycin®, Agrimicin® 100, and Actigard®) on fire blight suppression, and fruit yield and quality of apple (Malus domestica Borkh.) cv. Golden Glory. The experiment was conducted in a commercial orchard using a completely randomized block design, with six treatments: (1) Oxytetracycline [Ox], 110 mg L−1; (2) Kasugamycin [Kas], 4.7 mL L−1; (3) Oxytetracycline + Gentamicin [Ox + Gen], 48 mg L−1 + 12 mg L−1; (4) Streptomycin + Oxytetracycline [Str + Ox], 90 mg L−1 + 9 mg L−1; (5) Acibenzolar-S-methyl [ASM], 70 mg L−1; and (6) Control, only water, with four replications, and three 11-year-old trees as an experimental unit. Variables of infection including flowers, shoots and fruits, yield and fruit quality were evaluated. All treatments suppressed infection in flowers, shoots, and fruits. ASM provided the highest levels of reduction of flower and shoot infection, while Kas had the least effect on the reduction of infection in these variables. The Ox + Gen treatment had the greatest suppression of fruit infection, and the best results on fruit yield and quality, followed by Ox and ASM. This is the first study conducted to evaluate the efficacy of the active ingredients of five commercial products used for the management of fire blight in apple trees in Mexico. 相似文献
177.
Brandstaetter Christian Fricko Nora Rahimi Mohammad J. Fellner Johann Ecker-Lala Wolfgang Druzhinina Irina S. 《Biodegradation》2022,33(1):71-85
Biodegradation - Biological waste degradation is the main driving factor for landfill emissions. In a 2-year laboratory experiment simulating different landfill in-situ aeration scenarios, the... 相似文献
178.
Eukaryal translation initiation factor 2B (eIF2B) acts as guanine nucleotide exchange factor (GEF) for eIF2 and forms a central target for pathways regulating global protein synthesis. eIF2B consists of five non-identical subunits (α–ϵ), which assemble into a catalytic subcomplex (γ, ϵ) responsible for the GEF activity, and a regulatory subcomplex (α, β, δ) which regulates the GEF activity under stress conditions. Here, we provide new structural and functional insight into the regulatory subcomplex of eIF2B (eIF2BRSC). We report the crystal structures of eIF2Bβ and eIF2Bδ from Chaetomium thermophilum as well as the crystal structure of their tetrameric eIF2B(βδ)2 complex. Combined with mutational and biochemical data, we show that eIF2BRSC exists as a hexamer in solution, consisting of two eIF2Bβδ heterodimers and one eIF2Bα2 homodimer, which is homologous to homohexameric ribose 1,5-bisphosphate isomerases. This homology is further substantiated by the finding that eIF2Bα specifically binds AMP and GMP as ligands. Based on our data, we propose a model for eIF2BRSC and its interactions with eIF2 that is consistent with previous biochemical and genetic data and provides a framework to better understand eIF2B function, the molecular basis for Gcn−, Gcd− and VWM/CACH mutations and the evolutionary history of the eIF2B complex. 相似文献
179.
180.
Sofía Ochoa-López Nora Villamil Paulina Zedillo-Avelleyra Karina Boege 《Annals of botany》2015,116(5):797-806
Background and Aims Ontogenetic changes in anti-herbivore defences are common and result from variation in resource availability and herbivore damage throughout plant development. However, little is known about the simultaneous changes of multiple defences across the entire development of plants, and how such changes affect plant damage in the field. The aim of this study was to assess if changes in the major types of plant resistance and tolerance can explain natural herbivore damage throughout plant ontogeny.Methods An assessment was made of how six defensive traits, including physical, chemical and biotic resistance, simultaneously change across the major transitions of plant development, from seedlings to reproductive stages of Turnera velutina growing in the greenhouse. In addition, an experiment was performed to assess how plant tolerance to artificial damage to leaves changed throughout ontogeny. Finally, leaf damage by herbivores was evaluated in a natural population.Key Results The observed ontogenetic trajectories of all defences were significantly different, sometimes showing opposite directions of change. Whereas trichome density, leaf toughness, extrafloral nectary abundance and nectar production increased, hydrogen cyanide and compensatory responses decreased throughout plant development, from seedlings to reproductive plants. Only water content was higher at the intermediate juvenile ontogenetic stages. Surveys in a natural population over 3 years showed that herbivores consumed more tissue from juvenile plants than from younger seedlings or older reproductive plants. This is consistent with the fact that juvenile plants were the least defended stage.Conclusions The results suggest that defensive trajectories are a mixed result of predictions by the Optimal Defence Theory and the Growth–Differentiation Balance Hypothesis. The study emphasizes the importance of incorporating multiple defences and plant ontogeny into further studies for a more comprehensive understanding of plant defence evolution. 相似文献