Abstract:
:Gene expression circuitries with time-delayed expression profiles regulate key events, such as oscillating systems, noise elimination, and coordinated multi-step processes, in all organisms from bacteria to mammalian cells. We present the rational synthesis of a genetic circuit displaying time-delayed expression in silico and in mammalian cells. The network is based on a time-delay circuit, where the tetracycline-responsive transactivator (tTA) induces expression of the pristinamycin-responsive repressor PIP-KRAB, which silences expression of the terminal human placental secreted alkaline phosphatase (SEAP). While the addition of pristinamycin I inactivates PIP-KRAB and results in the immediate resumption of SEAP expression, addition of tetracycline abolishes PIP-KRAB synthesis. Consequently, SEAP production remains repressed until the PIP-KRAB buffer in the cell is eliminated. We characterized in silico and in vivo the time-delayed expression properties and analyzed the impact of the size and stability of the PIP-KRAB buffer on fine-tuning of the response kinetics. This tunable time-delay circuitry represents a biologic building block for emulating a fundamental circuit topology in integrated artificial synthetic gene networks for the design of tailor-made cell types and organisms.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Weber W,Kramer BP,Fussenegger Mdoi
10.1002/bit.21463subject
Has Abstractpub_date
2007-11-01 00:00:00pages
894-902issue
4eissn
0006-3592issn
1097-0290journal_volume
98pub_type
杂志文章abstract::Lipase from Candida cylindracea (CCL) was incorporated into polymerizable positively charged dialkylammonium bromide surfactant vesicles. The enzyme was incorporated by the use of the dehydration-rehydration method or by incubation. In the latter case, trapping efficiencies of up to 100% could be obtained. Activities ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420207
更新日期:1993-06-20 00:00:00
abstract::The reconstruction of functioning human tissues ex vivo is becoming an important part of biotechnology. There are compelling scientific, clinical, and biotechnological reasons for fully or partially reconstituting human tissues such as skin, bone marrow, and liver ex vivo. In particular, bone marrow is a tissue of muc...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420802
更新日期:1993-10-01 00:00:00
abstract::To build complex genetic networks with predictable behaviors, synthetic biologists use libraries of modular parts that can be characterized in isolation and assembled together to create programmable higher-order functions. Characterization experiments and computational models for gene regulatory parts operating in iso...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26918
更新日期:2019-05-01 00:00:00
abstract::An experimental study was undertaken to quantify the effects of infection cell density, medium condition, and surface aeration on recombinant protein yields in insect cells. In the absence of surface aeration and fresh medium, insect cells generated higher product yields (on a per cell basis) when infected with recomb...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390605
更新日期:1992-03-15 00:00:00
abstract::Enterokinase and recombinant enterokinase light chain (rEK(L)) have been used widely to cleave fusion proteins with the target sequence of (Asp)(4)-Lys. In this work, we show that their utility as a site-specific cleavage agent is compromised by sporadic cleavage at other sites, albeit at low levels. Further degradati...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10082
更新日期:2001-12-20 00:00:00
abstract::Lignocellulosic biofuels and chemicals have great potential to reduce our dependence on fossil fuels and mitigate air pollution by cutting down on greenhouse gas emissions. Chemical, thermal, and enzymatic processes are used to release the sugars from the lignocellulosic biomass for conversion to biofuels. These proce...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章,评审
doi:10.1002/bit.27639
更新日期:2020-11-26 00:00:00
abstract::Gluconic acid and sorbitol were simultaneously produced from glucose and Jerusalem artichoke using a glucose-fructose oxidoreductase of Zymomonas mobilis and inulinase. Inulinase was immobilized on chitin by cross-linking with glutaraldehyde. Cells of Z. mobilis permeabilized with toluene were coimmobilized with chiti...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390312
更新日期:1992-02-05 00:00:00
abstract::Based on batch cultivation data for the production of L-glutamic acid from glucose, a comparative evaluation was made for repeated batch cultivations using one and more fermentors. The problem was formulated as maximizing the productivity of metabolic product with the specified conversion with respect to the cell age ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260270524
更新日期:1985-05-01 00:00:00
abstract::Both the forward and backward reactions of xylose isomerase (Sweetzyme Q) with xylose and glucose as substrates have been studied in terms of kinetics and thermodynamics. The relationship between the two reactions can thus be determined. Much attention has been given to the reaction with xylose as substrate. The optim...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280508
更新日期:1986-05-01 00:00:00
abstract::In order to effectively treat obesity, it must be better understood at the cellular level with respect to metabolic state and environmental stress. However, current two-dimensional (2D) in vitro cell culture methods do not represent the in vivo adipose tissue appropriately due to the absence of complex architecture an...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25099
更新日期:2014-01-01 00:00:00
abstract::The feasibility of NO3- removal by the synergistic action of a prevailing denitrifying anoxic methane oxidising (DAMO), and nitrate-reducing and sulfide-oxidising bacterial (NR-SOB) consortium, using CH4 and H2 S from biogas as electron donors in a biotrickling filter was investigated. The influence of NO3- concentrat...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26092
更新日期:2017-03-01 00:00:00
abstract::We propose an in vitro selection strategy to identify bacteriophage variants that recognize metal ions in solution. In 6 M urea, phage T7 loses 99.9% of its activity in less than 5 min. Inactivation is accelerated by gold, but slowed by zinc and magnesium. Selection of phage over five generations in the presence of go...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260450512
更新日期:1995-03-05 00:00:00
abstract::The dissolved oxygen (DO) is an important variable in aerobic fermentations and affects the cell growth and product formation. Dissolved oxygen control is difficult in batch fermentations because of the time-varying conditions, time delays, and the probe dynamics. Modeling of the various patterns of biological activit...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19981005)60:1<1::aid-bit1>
更新日期:1998-10-05 00:00:00
abstract::Catalytic membranes, obtained by immobilizing thermophilic beta-glycosidase onto nylon supports, were used in a nonisothermal bioreactor to study the effect of temperature gradients on the rate of enzyme reaction. Two experimental approaches were carried out to explain the molecular mechanisms by which the temperature...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:1998-07-05 00:00:00
abstract::A metabolic shift from lactate production (LP) to net lactate consumption (LC) phenotype was observed in certain Chinese hamster ovary (CHO) cell lines during the implementation of a new chemically defined medium (CDM) formulation for antibody production. In addition, this metabolic shift typically leads to process pe...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23291
更新日期:2012-01-01 00:00:00
abstract::Pretreatment of high-crystalline cellulose with N-methyl-morpholine-N-oxide (NMO or NMMO) to improve bioethanol and biogas production was investigated. The pretreatments were performed at 90 and 120 degrees C for 0.5-15 h in three different modes, including dissolution (85% NMO), ballooning (79% NMO), and swelling (73...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22558
更新日期:2010-02-15 00:00:00
abstract::The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exer...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20225
更新日期:2004-10-20 00:00:00
abstract::Flow visualization using fluorescent microparticles and cell viability investigations are carried out to examine the mechanisms by which cells are seeded into scaffolds driven by surface acoustic waves. The former consists of observing both the external flow prior to the entry of the suspension into the scaffold and t...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22243
更新日期:2009-06-01 00:00:00
abstract::Targeted gene integration into site-specific loci can be achieved in Chinese hamster ovary (CHO) cells via CRISPR/Cas9 genome editing technology and the homology-directed repair (HDR) pathway. The low efficiency of HDR often requires antibiotic selection, which limits targeted integration of multiple genes at multiple...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.26002
更新日期:2016-11-01 00:00:00
abstract::After injury to the central nervous system, a glial scar develops that physically and biochemically inhibits axon growth. In the scar, activated astrocytes secrete inhibitory extracellular matrix, of which chondroitin sulfate proteoglycans (CSPGs) are considered the major inhibitory component. An inhibitory interface ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.24750
更新日期:2013-03-01 00:00:00
abstract::Soluble steel factor (SF) is a potent stimulator of hematopoietic progenitor cell proliferation in vitro, and cytokine combinations that include SF can support extensive expansions of hematopoietic cells. Recently, we showed that very primitive progenitor cells from normal human bone marrow require exposure to very hi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:1999-05-20 00:00:00
abstract::The effects of dilution rates on the performance of a two-stage fermentation system for a recombinant Escherichia coli culture were studied. Dilution rate determines the apparent or averaged specific growth rate of a heterogeneous population of cells in the recombinant culture. The specific growth rate affects the gen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260380805
更新日期:1991-10-20 00:00:00
abstract::Purified rat liver phenylalanine hydroxylase [L-phenylalanine:tetrahydropteridine:oxygen oxidoreductase (4-hydroxylating), EC 1.14.16.1] was immobilized with activated thiol-Sepharose 4B via disulfide bond formation, which is expected to immobilize the enzyme in its activated form through the SH modification. This imm...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260280422
更新日期:1986-04-01 00:00:00
abstract::The success of in situ bioremediation is often limited by the inability to bring bacteria in contact with the pollutant, which they will degrade. A bench-scale model aquifer was used to evaluate the impact of chemotaxis on the migration of bacteria toward the source of a chemical pollutant. The model was packed with s...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.23159
更新日期:2011-09-01 00:00:00
abstract::A technique has been developed for characterizing the in vivo behavior of key enzymes from intermediate measurements. The technique is based on the identification of characteristic reaction paths, and it depends on the time scale separation characteristics of the systems. It is shown that useful information can be obt...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260310813
更新日期:1988-05-20 00:00:00
abstract::The starting point for the present investigations was the finding that increasing influent concentrations from 10 to 380 mmol/L glucose decreased the attainable growth rate of an acidogenic population in continuous culture from 0.52 to 0.05 h(-1) To account for this phenomenon, a new kinetic model is developed that co...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260310714
更新日期:1988-05-01 00:00:00
abstract::In the last few years, an increasing number of biotechnological techniques have been applied to the restoration and conservation of works of art, paintings, old maps, and papers or books. Enzymes can solve problems that give restorers difficulties, although for many applications it is not possible to use soluble enzym...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10565
更新日期:2003-04-20 00:00:00
abstract::An examination is made of five methods for obtaining values of the enthalpy of formation of a unit mass of living Escherichia coli K-12 cells. The values obtained by these methods ranged from -88.95 kJ to -99.55 kJ, the gross average being 96.01 kJ, per unit carbon formula weight equivalent of living, hydrated cells. ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390103
更新日期:1992-01-05 00:00:00
abstract::The simultaneous growth and product formation in a microbial culture is an important feature of several laboratory, industrial, and environmental bioprocesses. Metabolic burden associated with product formation in these bioprocesses may lead to growth advantage of a nonproducing mutant leading to a loss of the produci...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260430403
更新日期:1994-02-20 00:00:00
abstract::The discovery of denitrifying anaerobic methane oxidation (DAMO) processes enables the complete nitrogen removal from wastewater by utilizing the methane produced on site from anaerobic digesters. This model-based study investigated the mechanisms and operational window for efficient nitrogen removal by coupling nitri...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25866
更新日期:2016-05-01 00:00:00