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排序方式: 共有378条查询结果,搜索用时 15 毫秒
361.
362.
Cynthia Lam Joseph Carver Domingos Ng Dejin Zhan Danming Tang Thara Kandamkalam Brad Snedecor Gavin Barnard Amy Shen Shahram Misaghi 《Biotechnology progress》2023,39(3):e3337
Chinese hamster ovary (CHO) cells are commonly used for the expression of therapeutic proteins. To increase the titer output of CHO production cultures either specific productivity (Qp), growth, or both need to be increased. Generally, Qp and growth are inversely correlated and cell lines with high Qp have slower growth and vice versa. During the cell line development (CLD) process, the faster-growing cells tend to take over the culture and represent the majority of the isolated clones post single cell cloning. In this study, combinations of regulated and constitutive expression systems were used to supertransfect targeted integration (TI) cell lines expressing the same antibody either constitutively or under-regulated expression. Clone screening with a hybrid expression system (inducible + constitutive) allowed identification and selection of higher titer clones under uninduced conditions, without a negative impact on cell growth during clone selection and expansion. Induction of the regulated promoter(s) during the production phase increased the Qp without negatively affecting growth, resulting in approximately twofold higher titers (from 3.5 to 6–7 g/L). This was also confirmed using a 2-site TI host where the gene of interest was expressed inducibly from Site 1 and constitutively from Site 2. Our findings suggest that such a hybrid expression CLD system can be used to increase production titers, providing a novel approach for expression of therapeutic proteins with high titer market demands. 相似文献
363.
Reinaldo Lourival Martin Drechsler Matthew E. Watts Edward T. Game Hugh P. Possingham 《Diversity & distributions》2011,17(2):297-310
Aim Using a probabilistic modelling framework, we aimed to incorporate landscape spatiotemporal dynamics into reserve design. We employed a spatially explicit stochastic model, which integrates both hydrological and biological processes, to simulate the wetland’s biological succession. Location Pantanal wetland (with 140,000 km2) between Brazil, Bolivia and Paraguay. Methods We used the reserve design software Marxan to optimize the current and future representation (up to 50 years) of 20% of five plant communities with maximum reliability (i.e. smallest uncertainty). The Kappa statistic was used to compare selection frequencies of individual sites through a set of planning timeframes (5, 17, 25 and 50 years) and the likely pattern of biological succession over these periods. Results Solutions based on static vegetation distributions were significantly dissimilar from solutions based on the expected modelled changes resulting from the flood disturbance and succession dynamics. Increasing the required reliability of biodiversity outcomes resulted in more expensive reserve solutions. We demonstrated the flexibility of probabilistic decision‐making methods to illuminate the trade‐offs between reliability and efficiency of site selection. Main conclusions Considering the importance of habitat heterogeneity to the principles and practice of systematic conservation planning, it is notable that landscape dynamics have not been a central theme in conservation planning. In the case of the Pantanal hydrosere, acknowledging and planning for temporal dynamics required an ability to model succession and define acceptable levels of outcome reliability, but ultimately improved the long‐term Adequacy of resulting reserve networks. 相似文献
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365.
Domingos F. M. Neto José R. S. Nascimento Gabriel R. Martins Ayla S. Silva Gilberto B. Domont Francisco A. P. Campos Fábio C. S. Nogueira 《Proteomics》2023,23(1):2200251
Açaí palm (Euterpe oleracea Mart.) seeds are a rich source of mannans, which can be used to generate bioethanol or be converted to high-value D-mannose, in addition to being a source of polyphenols with beneficial health properties. Here, we present a quantitative proteome dataset of açaí seeds at four stages of development (S1, S2, S3, and S4 stages), in which 2465 high confidence proteins were identified and 524 of them show statistically different abundance profiles during development. Several enzymes involved in the biosynthesis of nucleotide-sugars were quantified, especially those dedicated to the formation of GDP-mannose, which showed an increase in abundance between stages S1 and S3. Our data suggest that linear mannans found abundantly in endosperm cell walls are initially deposited as galactomannans, and during development lose the galactosyl groups. Two isoforms of alpha-galactosidase enzymes showed significantly increased abundances in the S3 and S4 stages. Additionally, we quantified the enzymes participating in the central pathway of flavonoid biosynthesis responsible for the formation of catechin and epicatechin, which are subunits of procyanidins, the main class of polyphenols in the açaí seeds. These proteins showed the same pattern of deposition, in which higher abundances were seen in the S1 and S2 stages. 相似文献
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Maria de Lourdes Lucio Ferrarese Nilson Evlázio de Souza João Domingos Rodrigues Osvaldo Ferrarese-Filho 《Acta Physiologiae Plantarum》2001,23(4):421-427
The objective of this research was to investigate how the allelochemical ferulic acid affects the carbohydrate and lipid contents
of soybean roots cultivated in nutrient culture. The results presented revealed that ferulic acid has significant effects
on carbohydrates by the increase in xylose, fructose and sucrose and decrease in glucose, after 24 h treatment of roots. Ferulic
acid increased the contents of saturated and unsaturated fatty acids of the polar and non-polar lipid fractions. The results
may contribute as additional data to explain allelopathic effects caused by ferulic acid. 相似文献
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Luciane Schons-Fonseca Josefa B. da?Silva Juliana S. Milanez Renan H. Domingos Janet L. Smith Helder I. Nakaya Alan D. Grossman Paulo L. Ho Renata MA da?Costa 《Nucleic acids research》2016,44(3):1179-1191
We determined the effects of DNA damage caused by ultraviolet radiation on gene expression in Leptospira interrogans using DNA microarrays. These data were integrated with DNA binding in vivo of LexA1, a regulator of the DNA damage response, assessed by chromatin immunoprecipitation and massively parallel DNA sequencing (ChIP-seq). In response to DNA damage, Leptospira induced expression of genes involved in DNA metabolism, in mobile genetic elements and defective prophages. The DNA repair genes involved in removal of photo-damage (e.g. nucleotide excision repair uvrABC, recombinases recBCD and resolvases ruvABC) were not induced. Genes involved in various metabolic pathways were down regulated, including genes involved in cell growth, RNA metabolism and the tricarboxylic acid cycle. From ChIP-seq data, we observed 24 LexA1 binding sites located throughout chromosome 1 and one binding site in chromosome 2. Expression of many, but not all, genes near those sites was increased following DNA damage. Binding sites were found as far as 550 bp upstream from the start codon, or 1 kb into the coding sequence. Our findings indicate that there is a shift in gene expression following DNA damage that represses genes involved in cell growth and virulence, and induces genes involved in mutagenesis and recombination. 相似文献
370.
de Paula Lima Jonatha Edson Margarido Vladimir Pavan Moresco Rafaela Maria de Jesus Rodrigues Domingos 《Hydrobiologia》2020,847(2):321-330
Hydrobiologia - While most anurans have limited vagility and local fidelity, there are some exceptions. In the present study, we used Boana boans, a large treefrog found throughout most of the... 相似文献