scholarly journals Highly Reversible Tunable Thermal-repressible Split-T7 RNA polymerases (Thermal-T7RNAPs) for dynamic gene regulation

2021 ◽  
Author(s):  
Wai Kit David Chee ◽  
Jing Wui Yeoh ◽  
Viet Linh Dao ◽  
Chueh Loo Poh
Keyword(s):  
Low Temperatures ◽  
Thermal Control ◽  
T7 Rna Polymerase ◽  
Thermal Regulation ◽  
Temperature Sensitive ◽  
Mutant Library ◽  
Alternative Mode ◽  
Regulate Cell Growth ◽  
Cellular Behaviors ◽  
Automated Screening

Temperature is a physical cue that is easy to apply, allowing cellular behaviors to be controlled in a contactless and dynamic manner via heat-inducible/repressible systems. However, existing heat-repressible systems are limited and rely on thermal sensitive mRNA or transcription factors which function at low temperatures, lack tunability, suffer delays or overly-complex. To provide an alternative mode of thermal regulation, we developed a library of compact, reversible and tunable thermal-repressible split-T7 RNA polymerase systems (Thermal-T7RNAPs) which fuses temperature-sensitive domains of Tlpa protein with split-T7RNAP to enable direct thermal control of the T7RNAP activity between 30-42 °C. We generated a large mutant library with varying thermal performances via automated screening framework to extend temperature tunability. Lastly, using the mutants, novel thermal logic circuitry was implemented to regulate cell growth and achieve active thermal control of the cell proportions within co-cultures. Overall, this technology expands avenues for thermal control in biotechnology applications.

scholarly journals Enhanced stability and polyadenylation of select mRNAs support rapid thermogenesis in the brown fat of a hibernator

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Katharine R Grabek ◽  
Cecilia Diniz Behn ◽  
Gregory S Barsh ◽  
Jay R Hesselberth ◽  
Sandra L Martin
Keyword(s):  
Mathematical Modeling ◽  
Low Temperatures ◽  
Temperature Sensitive ◽  
Molecular Pathways ◽  
Physiological Regulation ◽  
Brown Adipose ◽  
Activity Cycles ◽  
Intense Activity ◽  
Enhanced Stability ◽  
Periodic Arousal

During hibernation, animals cycle between torpor and arousal. These cycles involve dramatic but poorly understood mechanisms of dynamic physiological regulation at the level of gene expression. Each cycle, Brown Adipose Tissue (BAT) drives periodic arousal from torpor by generating essential heat. We applied digital transcriptome analysis to precisely timed samples to identify molecular pathways that underlie the intense activity cycles of hibernator BAT. A cohort of transcripts increased during torpor, paradoxical because transcription effectively ceases at these low temperatures. We show that this increase occurs not by elevated transcription but rather by enhanced stabilization associated with maintenance and/or extension of long poly(A) tails. Mathematical modeling further supports a temperature-sensitive mechanism to protect a subset of transcripts from ongoing bulk degradation instead of increased transcription. This subset was enriched in a C-rich motif and genes required for BAT activation, suggesting a model and mechanism to prioritize translation of key proteins for thermogenesis.

Restoration of thermoregulation after exercise

2017 ◽  
Vol 122 (4) ◽  
pp. 933-944 ◽  
Author(s):  
Glen P. Kenny ◽  
Ryan McGinn
Keyword(s):  
Heat Loss ◽  
Core Temperature ◽  
Current Knowledge ◽  
Thermal Control ◽  
The Body ◽  
Body Core Temperature ◽  
Whole Body ◽  
Temperature Sensitive ◽  
Internal Core ◽  
Body Core

Performing exercise, especially in hot conditions, can heat the body, causing significant increases in internal body temperature. To offset this increase, powerful and highly developed autonomic thermoregulatory responses (i.e., skin blood flow and sweating) are activated to enhance whole body heat loss; a response mediated by temperature-sensitive receptors in both the skin and the internal core regions of the body. Independent of thermal control of heat loss, nonthermal factors can have profound consequences on the body’s ability to dissipate heat during exercise. These include the activation of the body’s sensory receptors (i.e., baroreceptors, metaboreceptors, mechanoreceptors, etc.) as well as phenotypic factors such as age, sex, acclimation, fitness, and chronic diseases (e.g., diabetes). The influence of these factors extends into recovery such that marked impairments in thermoregulatory function occur, leading to prolonged and sustained elevations in body core temperature. Irrespective of the level of hyperthermia, there is a time-dependent suppression of the body’s physiological ability to dissipate heat. This delay in the restoration of postexercise thermoregulation has been associated with disturbances in cardiovascular function which manifest most commonly as postexercise hypotension. This review examines the current knowledge regarding the restoration of thermoregulation postexercise. In addition, the factors that are thought to accelerate or delay the return of body core temperature to resting levels are highlighted with a particular emphasis on strategies to manage heat stress in athletic and/or occupational settings.

Different temperature relations of two species of toads that coexist at the border of their geographical distributions

1997 ◽  
Vol 18 (3) ◽  
pp. 259-268 ◽  
Author(s):  
U. Katz ◽  
Nira Gil
Keyword(s):  
Body Temperature ◽  
Low Temperature ◽  
Low Temperatures ◽  
Central Mechanism ◽  
Tropical Species ◽  
Temperature Sensitive ◽  
Ecological Situation ◽  
Heating Rates ◽  
Bufo Viridis

AbstractTemperature relations of two species of toads (Bufo viridis and Bufo regularis) that overlap at the border of their geographical distributions were studied in the laboratory in temperatures between 25°C and 2°C. Bufo regularis, a tropical species, could not survive at low temperatures that eventually led to its death in 1-2 days. The two species did not differ in their cooling and heating rates. At temperatures below 8-10°C, Bufo viridis maintained a body temperature that was higher than ambient by 1-2°C, while body temperature of Bufo regularis equaled that of the environment. In Bufo regularis heart beats ceased at low temperatures (< 4°C), whereas in Bufo viridis at the same temperature, a rate of 6-9 beats/min was sustained. Our experiments suggest that Bufo viridis is endowed with particular capacities that allow it to remain active at low temperatures, while in Bufo regularis, a temperature-sensitive central mechanism seems to be damaged at low temperature. The ability of Bufo viridis to endure low temperatures and to remain active in this condition is specific to the species, and is not related directly to the immediate ecological situation of the animal.

scholarly journals Genetic Analysis of Influenza Virus NS1 Gene: a Temperature-Sensitive Mutant Shows Defective Formation of Virus Particles

2005 ◽  
Vol 79 (24) ◽  
pp. 15246-15257 ◽  
Author(s):  
Urtzi Garaigorta ◽  
Ana M. Falcón ◽  
Juan Ortín
Keyword(s):  
Amino Acid ◽  
Genetic Analysis ◽  
Terminal Region ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mutant Library ◽  
Ns1 Protein ◽  
Neuraminidase Treatment ◽  
Virus Particles ◽  
Ns1 Gene

ABSTRACT To perform a genetic analysis of the influenza A virus NS1 gene, a library of NS1 mutants was generated by PCR-mediated mutagenesis. A collection of mutant ribonucleic proteins containing the nonstructural genes was generated from the library that were rescued for an infectious virus mutant library by a novel RNP competition virus rescue procedure. Several temperature-sensitive (ts) mutant viruses were obtained by screening of the mutant library, and the sequences of their NS1 genes were determined. Most of the mutations identified led to amino acid exchanges and concentrated in the N-terminal region of the protein, but some of them occurred in the C-terminal region. Mutant 11C contained three mutations that led to amino acid exchanges, V18A, R44K, and S195P, all of which were required for the ts phenotype, and was characterized further. Several steps in the infection were slightly altered: (i) M1, M2, NS1, and neuraminidase (NA) accumulations were reduced and (ii) NS1 protein was retained in the nucleus in a temperature-independent manner, but these modifications could not justify the strong virus titer reduction at restrictive temperature. The most dramatic phenotype was the almost complete absence of virus particles in the culture medium, in spite of normal accumulation and nucleocytoplasmic export of virus RNPs. The function affected in the 11C mutant was required late in the infection, as documented by shift-up and shift-down experiments. The defect in virion production was not due to reduced NA expression, as virus yield could not be rescued by exogenous neuraminidase treatment. All together, the analysis of 11C mutant phenotype may indicate a role for NS1 protein in a late event in virus morphogenesis.

scholarly journals Dominant suppressors of yeast actin mutations that are reciprocally suppressed.

Genetics ◽  
1989 ◽  
Vol 121 (4) ◽  
pp. 675-683
Author(s):  
A E Adams ◽  
D Botstein
Keyword(s):  
High Temperature ◽  
Linkage Group ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Mutant Library ◽  
Suppressor Mutations ◽  
Extragenic Suppressor ◽  
New Gene ◽  
Allele Specificity

Abstract A gene whose product is likely to interact with yeast actin was identified by the isolation of pseudorevertants carrying dominant suppressors of the temperature-sensitive (Ts) act1-1 mutation. Of 30 independent revertants analyzed, 29 were found to carry extragenic suppressor mutations and of these, 24/24 tested were found to be linked to each other. This linkage group identifies a new gene SAC6, whose product, by several genetic criteria, is likely to interact intimately with actin. First, although act1-1 sac6 strains are temperature-independent (Ts+), 4/17 sac6 mutant alleles tested are Ts in an ACT1+ background. Moreover, four Ts+ pseudorevertants of these ACT1+ sac6 mutants carry suppressor mutations in ACT1; significantly, three of these are again Ts in a SAC6+ background, and are most likely new act1 mutant alleles. Thus, mutations in ACT1 and SAC6 can suppress each other's defects. Second, sac6 mutations can suppress the Ts defects of the act1-1 and act1-2, but not act1-4, mutations. This allele specificity indicates the sac6 mutations do not suppress by simply bypassing the function of actin at high temperature. Third, act1-4 sac6 strains have a growth defect greater than that due to either of the single mutations alone, again suggesting an interaction between the two proteins. The mutant sac6 gene was cloned on the basis of dominant suppression from an act1-1 sac6 mutant library, and was then mapped to chromosome IV, less than 2 cM from ARO1.

scholarly journals Evaluating the efficiency of utilizing selectively optimized metamaterial nanostructures for passive radiative cooling of satellites and components

2019 ◽  
Vol 6 ◽  
pp. 110-123
Author(s):  
Federico Moreno ◽  
Swapnil Poudyal ◽  
Otto Cranwell ◽  
Ben Andrew
Keyword(s):  
Meta Analysis ◽  
Inductive Reasoning ◽  
Visible Spectrum ◽  
Optical Filters ◽  
Thermal Control ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Temperature Sensitive ◽  
Selective Absorption ◽  
Nanophotonic Structures

The need for efficient, smart radiators and thermal control technologies will be imperative to ensure the longevity of satellites and for carrying out temperature sensitive operations in space. Advancement in nanofabrication techniques has brought about the ability to create metamaterial nanostructures and selectively control their optical properties so that they reflect better in the visible spectrum and strongly emit in the infrared spectrum, which allows for better cooling. This meta-analysis looks at contemporary research that has utilised metamaterial nanostructures for passive radiative cooling attempting to identify the cooling trends among these structures. The absorbance, emissivity and reflection spectra of these structures are compared, and their effectiveness compared to conventional coolant coatings is critiqued upon. The defining thermodynamic parameters for this study were radiative cooling power and temperature reduction. Through inductive reasoning, we predict that the emissivity in the infrared of a pyramidal layered structure of Al2O3, TiO2 and SiO2 can outperform current material choices. Improving efficiency with the prediction outlined can provide increased radiative cooling. Keywords: Passive radiative cooling; thermal radiation; metamaterials; broadband optical filters; selective absorption and emission; two-dimensional thin film coatings; nanophotonic structures

Measurement of Total Hemispherical Emittance of Spacecraft Thermal Control Coatings at Low Temperatures

2012 ◽  
Vol 33 (9) ◽  
pp. 792-799 ◽  
Author(s):  
Govinda R. Yenni ◽  
Amrit Ambirajan ◽  
Narasinganallur K. Sundaresan ◽  
Arumugam Ramasamy
Keyword(s):  
Low Temperatures ◽  
Thermal Control ◽  
Total Hemispherical Emittance ◽  
Thermal Control Coatings ◽  
Spacecraft Thermal Control

scholarly journals Molecular Lesions Associated With Alleles of decapentuplegic Identify Residues Necessary for TGF-β/BMP Cell Signaling in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 493-505 ◽  
Author(s):  
Kristi Wharton ◽  
Robert P Ray ◽  
Seth D Findley ◽  
Holly E Duncan ◽  
William M Gelbart
Keyword(s):  
Cell Signaling ◽  
Low Temperatures ◽  
Point Mutations ◽  
Molecular Probes ◽  
Genetic Interactions ◽  
Temperature Sensitive ◽  
In Vitro Mutagenesis ◽  
Mutant Phenotypes

Abstract We have identified the molecular lesions associated with six point mutations in the Drosophila TGF-β homologue decapentaplegic (dpp). The sites of these mutations define residues within both the pro and ligand regions that are essential for dpp function in vivo. While all of these mutations affect residues that are highly conserved among TGF-β superfamily members, the phenotypic consequences of the different alleles are quite distinct. Through an analysis of these mutant phenotypes, both in cuticle preparations and with molecular probes, we have assessed the functional significance of specific residues that are conserved among the different members of the superfamily. In addition, we have tested for conditional genetic interactions between the different alleles. We show that two of the alleles are temperature sensitive for the embyronic functions of dpp, such that these alleles are not only embryonic viable as homozygotes but also partially complement other dpp hypomorphs at low temperatures. Our results are discussed with regard to in vitro mutagenesis data on other TGF-β-like molecules, as well as with regard to the regulation of dpp cell signaling in Drosophila.

scholarly journals INVESTIGATION OF THE TEMPERATURE-SENSITIVE CHARACTERISTIC OF GRAFTED GELATIN-PLURONIC HYDROGEL WITH INCORPORATION CALOPHYLLUM INOPHYLLUM OIL EXTRACT APPLIED FOR WOUND HEALING

2020 ◽  
Vol 1 (35) ◽  
pp. 62-68
Author(s):  
Giang Hoang Le ◽  
Yen Nguyen Tram Chau ◽  
Trinh Thi Ngoc Huynh
Keyword(s):  
Tissue Regeneration ◽  
Low Temperatures ◽  
Sol Gel ◽  
Ultrasonic Waves ◽  
Pluronic F127 ◽  
Temperature Sensitive ◽  
Calophyllum Inophyllum ◽  
Gel Film ◽  
Oil Extract ◽  
Calophyllum Inophyllum Oil

Temperature-sensitive hydrogels were synthesized from gelatin-pluronic F127 with Calophyllum inophyllum oil extract incorporated as the the active ingredient by ultrasonic waves to increase the healing effect of wound treatments. The temperaturesensitive nature of the hydrogels were determined using the inversion tube  method along with rheological property measurements. The sol-gel state of the hydrogels were found to change with temperature, at low-temperatures hydrogel gelatin - pluronic F127 is found to be in a liquid state, and when the temperature raised due to body temperature the hydrogel became a gel film. In addition, the hydrogel containing Calophyllum inophyllum oil has the ability to heal burns in the second degree after 10days of treatment. These results showed the potential application of the biomaterial in tissue regeneration.

scholarly journals Rho-kinase and PKCα Inhibition Induces Primary Cilia Elongation and Alters the Behavior of Undifferentiated and Differentiated Temperature-sensitive Mouse Cochlear Cells

2019 ◽  
Vol 67 (7) ◽  
pp. 523-535
Author(s):  
Akito Kakiuchi ◽  
Takayuki Kohno ◽  
Takuya Kakuki ◽  
Yakuto Kaneko ◽  
Takumi Konno ◽  
...  
Keyword(s):  
Hair Cells ◽  
Primary Cilia ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Temperature Sensitive ◽  
Undifferentiated Cells ◽  
Cellular Behaviors ◽  
Dependent Cell ◽  
Cycle Dependent ◽  
G1 Cells

Primary cilia, regulated via distinct signal transduction pathways, play crucial roles in various cellular behaviors. However, the full regulatory mechanism involved in primary cilia development during cellular differentiation is not fully understood, particularly for the sensory hair cells of the mammalian cochlea. In this study, we investigated the effects of the Rho-kinase inhibitor Y27632 and PKCα inhibitor GF109203X on primary cilia-related cell behavior in undifferentiated and differentiated temperature-sensitive mouse cochlear precursor hair cells (the conditionally immortalized US/VOT-E36 cell line). Our results indicate that treatment with Y27632 or GF109203X induced primary cilia elongation and tubulin acetylation in both differentiated and undifferentiated cells. Concomitant with cilia elongation, Y27632 treatment also increased Hook2 and cyclinD1 expression, while only Hook2 expression was increased after treatment with GF109203X. In the undifferentiated cells, we observed an increase in the number of S and G2/M stage cells and a decrease of G1 cells after treatment with Y27632, while the opposite was observed after treatment with GF109203X. Finally, while both treatments decreased oxidative stress, only treatment with Y27632, not GF109203X, induced cell cycle-dependent cell proliferation and cell migration.

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