Temperature-sensitive Function Research Articles

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.3

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.3

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.2

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.2

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.1

Transient Receptor Potential channels (TRP) in GtoPdb v.2023.1

Keynote Speakers of ICMSE2017

Keynote Speaker IFlexible piezoresistive material composed of conductive fillers and polymerProf. Luheng WangProfessor, doctoral supervisor, Shenghua Scholar Distinguished Professor, Central South University, ChinaBiography:Luheng Wang received the Ph.D. degree from the Department of Precision Instruments and Mechanology, Tsinghua University, Beijing, China. He is a professor and doctoral supervisor with the School of Information Science and Engineering, Central South University, Changsha, China. He is currently the Shenghua scholar distinguished professor, and the leader of the CSU flexible sensor lab. His current research interest is to study the key mechanical/electrical properties and mechanisms for the novel flexible sensitive materials which possess multi-sensing-functions (e.g. pressure sensitive function, temperature sensitive function, magnetic sensitive function, and gas sensitive function, etc.), and to develop the multi-functional flexible sensor system based on the aforementioned sensitive materials.Research interests:Novel flexible sensitive materials, pressure sensitive function, temperature sensitive function, magnetic sensitive function, and gas sensitive function.:The composite composed of the conductive fillers and the polymer, which possesses not only the flexibility but also the piezoresistivity, can be used to develop the flexible pressure sensor. The progress in the research on the piezoresistivity of the composite is reported. The existing theories to explain the piezoresistive phenomena of the composite are summarized, including the “conductive filler gap theory”, the “conducting path theory”, the “conductive phase content theory”, and the “effective conductive path theory”. Furthermore, the limitations and the advantages of the aforementioned theories are compared and analyzed. Finally, the applications of the composite in the development of the flexible pressure sensor are presented.Keynote Speaker ⅡEmergence of topological and topological crystalline phases in T1BiS2 and T1SbS2Dr. Udo Erich Schwingenschl¨oglDoctor, King Abdullah University Of Science and Technology (KAUST), GermanyBiography:Dr. Udo Erich Schwingenschl¨ogl was a scientific employee in university of Augsburg, Germany from 07/2001–09/2004. From 09/2004–02/2008, he was a Secondary School Teacher in State of Bavaria, Germany. And from 03/2008–08/2008 he worked as a visiting Professor in University of Bras´ılia (ICCMP), Brazil. And during 09/2008– 10/2011, he was an assistant Professor in KAUST, Saudi Arabia. While during 09/2009–11/2012, he was the Program Chair “Materials Science & Engineering” of KAUST, Saudi Arabia. During 11/2011–06/2014, he was the Associate Professor in KAUST, Saudi Arabia, again. During 12/2012–06/2015, he became the Associate Dean “Physical Science & Engineering” in KAUST, Saudi Arabia. And until now, he was the professor of KAUST, Saudi Arabia.Research interests:Computational Physics and Materials Science, New Topological Materials:Using first-principles calculations, we investigate the band structure evolution and topological phase transitions in T1BiS2 and T1SbS2 under hydrostatic pressure as well as uniaxial and biaxial strain. The phase transitions are identified by parity analysis and by calculating the surface states. Zero, one, and four Dirac cones are found for the (111) surfaces of both T1BiS2 and T1SbS2 when the pressure grows, which confirm trivial-nontrivial-trivial phase transitions. The Dirac cones at the M points are anisotropic with large out-of-plane component. T1BiS2 shows normal, topological, and topological crystalline insulator phases under hydrostatic pressure, thus being the first compound to exhibit a phase transition from a topological to a topological crystalline insulator.

O-Fucose Monosaccharide of Drosophila Notch Has a Temperature-sensitive Function and Cooperates with O-Glucose Glycan in Notch Transport and Notch Signaling Activation

Notch (N) is a transmembrane receptor that mediates the cell-cell interactions necessary for many cell fate decisions. N has many epidermal growth factor-like repeats that are O-fucosylated by the protein O-fucosyltransferase 1 (O-Fut1), and the O-fut1 gene is essential for N signaling. However, the role of the monosaccharide O-fucose on N is unclear, because O-Fut1 also appears to have O-fucosyltransferase activity-independent functions, including as an N-specific chaperon. Such an enzymatic activity-independent function could account for the essential role of O-fut1 in N signaling. To evaluate the role of the monosaccharide O-fucose modification in N signaling, here we generated a knock-in mutant of O-fut1 (O-fut1(R245A knock-in)), which expresses a mutant protein that lacks O-fucosyltransferase activity but maintains the N-specific chaperon activity. Using O-fut1(R245A knock-in) and other gene mutations that abolish the O-fucosylation of N, we found that the monosaccharide O-fucose modification of N has a temperature-sensitive function that is essential for N signaling. The O-fucose monosaccharide and O-glucose glycan modification, catalyzed by Rumi, function redundantly in the activation of N signaling. We also showed that the redundant function of these two modifications is responsible for the presence of N at the cell surface. Our findings elucidate how different forms of glycosylation on a protein can influence the protein's functions.

Mutations within a conserved protein kinase A recognition sequence confer temperature-sensitive and partially defective activities onto mouse c-Rel

We have created two mutants of mouse transcription factor c-Rel (c-G29E and c-R266H) that are analogous to mutants previously shown to have temperature-sensitive (ts) functions for the homologous Drosophila protein Dorsal and the retroviral oncoprotein v-Rel. In vitro, c-R266H shows both a ts and a concentration-dependent ability to bind DNA, suggesting that the lesion affects the ability of c-Rel to form homodimers. In contrast, the ability of mouse c-G29E to bind DNA in vitro is not ts. c-Rel mutant c-R266H also shows a ts ability to activate transcription from a κB-site reporter plasmid, whereas c-G29E activates transcription well above control levels at both 33 and 39 °C. Insertion of two amino acids (Pro–Trp) between amino acids 266 and 267 in mouse c-Rel (mutant c-SPW) also creates a c-Rel protein with distinct properties: mutant c-SPW is partially defective in that it cannot form DNA-binding homodimers but can form DNA-binding heterodimers with p50. Interestingly, the mutations in c-Rel that affect homodimer formation (c-R266H and c-SPW) fall within a consensus protein kinase A recognition sequence but are not predicted to lie in the dimer interface. Conditional and partially defective mutants such as those described herein may be useful for identifying physiological responses and genes regulated by specific Rel/NF-κB family members.

Trienoic fatty acids and plant tolerance of temperature

The biophysical reactions of light harvesting and electron transport during photosynthesis take place in a uniquely constructed bilayer, the thylakoid. In all photosynthetic eukaryotes, the complement of atypical glycerolipid molecules that form the foundation of this membrane are characterised by sugar head-groups and a very high level of unsaturation in the fatty acids that occupy the central portion of the thylakoid bilayer. alpha-linolenic (18:3) or a combination of 18:3 and hexadecatrienoic (16:3) acids typically account for approximately two-thirds of all thylakoid membrane fatty acids and over 90% of the fatty acids of monogalactosyl diacylglycerol, the major thylakoid lipid [1, 2]. The occurrence of trienoic fatty acids as a major component of the thylakoid membrane is especially remarkable since these fatty acids form highly reactive targets for active oxygen species and free radicals, which are often the by-products of oxygenic photosynthesis. Photosynthesis is one of the most temperature-sensitive functions of plant [3, 4]. There remains a widespread belief that these trienoic fatty acids might have some crucial role in plants to be of such universal occurrence, especially in photosynthesis tolerance of temperature [5].

Induction of tetraploid DNA content by simian virus 40 is dependent on T-antigen function in the G2 phase of the cell cycle

Previous experiments with the simian virus 40 mutant tsA357R-K (tsA30) demonstrated a T-antigen function that is required for production of cells with a greater-than-G2-phase DNA content. In this study, temperature shift experiments indicated that the temperature-sensitive function of tsA357R-K, which is necessary for entry into the greater-than-G2 phase, is not required in G1 or S but must be supplied in the G2 phase.

Further studies of 31 temperature-sensitive mutants of mouse cytomegalovirus: Thermal stability, replication and analysis of temperature-sensitive functions by temperature shift

Further studies of 31 temperature-sensitive mutants of mouse cytomegalovirus: Thermal stability, replication and analysis of temperature-sensitive functions by temperature shift

Further studies of 31 temperature-sensitive mutants of mouse cytomegalovirus: Thermal stability, replication and analysis of temperature-sensitive functions by temperature shift

A study of 31 temperature-sensitive mutants of mouse cytomegalovirus has indicated that two mutants (tsm1, tsm31) may be defective in immediate-early/early functions, two (tsm2, tsm3) may be defective in early functions and six (tsm9, tsm18, tsm22, tsm23, tsm28, tsm30) may be defective in early/late functions while the remainder are late function-defective mutants as determined by temperature-shift experiments. Three mutants (tsm1, tsm2, tsm3) were more thermostable than wild-type virus while three (tsm16, tsm26, tsm28) were more thermolabile; the remainder were similar in their thermostability to wild-type virus.

Molecular pathogenesis of equine coital exanthema: Temperature-sensitive function(s) in cells infected with equine herpesviruses

Preliminary experiments have revealed that several laboratory and wild-type strains of the equine herpesvirus (EHV) triad were temperature-sensitive for growth when assayed at 39°C. The efficiencies of plating (EOP) observed were 10 −2 for both EHV 1 and 2, and 1 × 10 −6 for EHV 3. The EOPs were determined by plaque assays which compared titrations at 34°C and 39°C on equine fetal dermal fibroblast cells. Growth yield experiments, assayed at 34°C, reflected these EOP's, but did not indicate any difference in yields when infected cultures were incubated at 34°C and 37°C. Temperature shift experiments with EHV 3-infected cultures revealed that a temperature-sensitive function(s) responsible for the reduction in titer appeared to be a late function(s). All strains examined appeared to incorporate H 3-thymidine into viral-density DNA at the non-permissive temperature of 39°C. Electron microscopy of EHV 3-infected cell cultures, incubated continuously at the non-permissive temperature and examined at 18 h after infection, revealed structures consistent with the accumulation of nucleocapsids within the nucleus. The evidence presented is consistent with the hypothesis that in equine dermal cells infected with a plaque-purified wild-type strain of EHV 3 (1118LP), a function needed for the egress of nucleocapsids from the nucleus is absent at 39°C. The significance of these findings relative to the pathogenicity of the disease (equine coital exanthema) caused by this virus is discussed.

DNA synthesis in BalB/C-3T3 ts 2 cells is restricted by a temperature-sensitive function of late G1 phase.

ts 2 BalB/C-3T3 mouse fibroblasts are cdc mutants, which arrest late in G1, at or near the G1/S traverse, upon full expression of the heat-sensitive lesion. The kinetics of temperature inhibition of DNA synthesis in logarithmically growing cultures reveal three stages of heat inactivation. During the first generation time equivalent, normal semiconservative, semidiscontinuous replication proceeds but is reduced as cells exit and do not reenter S phase. During a second such period, a minimal rate of normal DNA synthesis is maintained. Thereafter, as the cells move into a third aborted cell division cycle, the rate of DNA synthesis increases. However, all semiconservative synthesis is then replaced by DNA repair replication. Temperature inactivation of the ts 2 protein results in shutdown of nuclear DNA synthesis. In contrast, normal replication of mitochondrial DNA proceeds at control rate throughout the first stage of temperature inactivation. Synthesis of this organellar genome is quantitatively reduced as the cells move into the second phase of heat inhibition. Titration of chromatin-bound DNA with ethidium bromide revealed that wild-type cells exhibit a changing DNA topology as the temperature is raised. Temperature-inactivated ts 2 cells behave as though their DNA has been topologically frozen in the configuration of control cells at or near entry into S phase.

Early and delayed shut-off of host protein synthesis in cells infected with herpes simplex virus.

A mutant of herpes simplex virus type 1 [HSV-1(HFEM)], tsB7, appears to have two temperature-sensitive functions. One is required during the first hour of infecting a cell (suggesting that it is performed by a virion protein) and the other is the non-essential function of "early shut-off" of cellular protein synthesis, which is mediated by a virion protein. The latter function remained temperature-sensitive in a revertant virus (RC2) grown at the non-permissive temperature (39 degrees C). However, under these conditions RC2 did cause inhibition of host synthesis, showing that "delayed shut-off", requiring virus protein synthesis, can occur independently of early shut-off, which is mediated by a virion protein. Early shut-off by u.v.-irradiated tsB7 was reversed when the temperature was raised, whereas delayed shut-off by intact tsB7 was not. Of two wild-type strains of virus examined, HSV-1(F) also exhibited temperature-sensitive early shut-off, but HSV-2(G) did not.

Strain-Dependent Temperature-Sensitive Phase in Crown Gall Tumorigenesis

The effect of high temperature treatments on the early stages of crown gall tumorigenesis in sunflowers was investigated. Treatments of 32 C initiated at various times during the first ten days after infection had a similar effect on tumors induced by Agrobacterium tumefaciens strains B(6) and C58. Tumor growth was sensitive to 32 C until 60 to 72 hours after infection and was stimulated by 32 C after that time. Therefore, the "inception phase" for both C58 and B(6)-induced tumors ends between 60 to 72 hours after infection. In contrast, B(6) and C58 tumors varied in their response to 37 C treatments during the first 168 hours after infection. Both C58 and B(6) tumors were sensitive to 37 C during the first 72 hours; however, B(6) tumors became resistant to 37 C after 96 hours, whereas C58-induced tumors remained sensitive until 144 to 168 hours after infection.The growth rate of C58 and B(6) tumors in plants moved to 32 C at 90 hours after infection was the same. B(6) tumors in plants moved to 37 C at 90 hours after infection also continued to grow rapidly, whereas C58 tumors in plants moved to 37 C at 90 hours exhibited a complete cessation of tumor growth. The 37 C temperature-sensitive period specific to C58 tumors ceases by 168 hours after infection. This indicates that the temperature-sensitive functions are no longer required after 168 hours. The possible significance of this work with regard to the presence of a temperature-sensitive plasmid, pTiC58, in strain C58 and the mechanism of tumor-inducing plasmid DNA maintenance in incipient tumor cells is discussed.

A mutation, bsu, that suppresses temperature-sensitive dnaB function in Escherichia coli K12.

A mutation of Escherichia coli K12 that suppresses certain temperature-sensitive dnaB mutations was identified. The suppressor, named bsu maps very near the dnaG mutations. The bsu mutation in dnaB bacteria appears to be dominant over the wild-type allele, and suppresses specifically the temperature-sensitive dnaB mutations which are revertible phenotypically when salt is present. The observed specificity in suppression suggests that the product of bsu alone cannot substitute for the defective dnaB gene products. These findings suggest strongly that gene products of bsu and dnaB interact with each other in the process of DNA replication in E. coli.

Isolation and preliminary characterization of temperature-sensitive mutants of visna virus

Temperature-sensitive mutants of visna virus have been isolated from N-methyl- N′-nitro- N-nitroso-guanidine mutagenized virus. These mutants have been partially characterized and have been separated into three classes based on the time after infection when the temperature-sensitive function was expressed.

Cytoplasmic regulation of two G1-specific temperature-sensitive functions.

tsAF8 and ts13 cells are temperature-sensitive (ts) mutants of BHK cells that specifically arrest, at nonpermissive temperature, in the G1 phase of the cell cycle. These two mutants can complement each other. Both cell lines can be made quiescent by serum deprivation (G0). When subsequently stimulated by serum, they can enter S phase at 34 degrees C but not at 39.5 degrees-40.6 degrees C. We have used these mutants to determine whether the nucleus is needed during the G0 leads to S transition for the expression of the G1 ts functions. For this purpose, we fused cytoplasts of G0-tsAF8 with whole ts13 cells in G0, and cytoplasts of G0-ts13 with whole tsAF8 cells in G0. Serum stimulation at the nonpermissive temperature induced DNA synthesis in both types of such fusion products. No DNA synthesis was induced by serum stimulation at the nonpermissive temperature in fusion products constructed between either G0-tsAF8 cytoplasts and whole G0-tsAF8 cells or G0-ts13 cytoplasts and whole G0-ts13 cells. These results demonstrate that the information for these two ts functions, which are required for entry of serum-stimulated cells into the S phase, are already present in the cytoplasm of G0 cells--that is, before serum stimulation commits them to the transition from the nonproliferating to the proliferating state.

Replication and maturation of phage P22 in a mutant of Salmonella typhimurium temperature sensitive in initiation of DNA replication

TB37 is a dna A-mutant of Salmonella typhimurium in which the initiation of DNA replication at the origin is stopped at 42 degrees C. DNA synthesis in uninfected cells of this strain and in cells infected by phage P22 was followed by the pulse labelling technique. DNA replication ceases completely after about 50 minutes at the high temperature. After lytic infection with P22 (c2) at this time, DNA synthesis starts immediately and increases at a rate well comparable to the permissive control. Obviously the temperature sensitive function of the dnaA-product is dispensable for P22 DNA replication, especially for its initiation. This result is confirmed by the normal yield of phage particles under these conditions, provided that a late step in P22 maturation which naturally is temperature sensitive can proceed at low temperature. If TB37 is infected at 42 degrees C with P22 wild type, an unexpected high rate of phage controlled DNA synthesis is observed. Preliminary results seem to indicate that the process of integration is a prerequisite for part of this synthesis.

Enhancement of the synthesis of specific cellular polypeptides in a temperature-sensitive Chinese hamster cell line (K12) defective for entry into S phase.

Temperature-sensitive Chinese hamster cells (K12) have been shown to be defective for the initiation of new rounds of DNA replication when incubated at the restrictive temperature (40.5 degrees). By temperature shift experiments with synchronous cultures, we have marked out the step at which the mutation is expressed as the four hours preceding the initiation of DNA synthesis. The block imposed by the mutation has been shown to be irreversible. In order to approach the biochemical characterization of the temperature-sensitive function in K12 cells, we have analyzed the cellular proteins synthesized under permissive (35 degrees) and restrictive temperatures. The synthesis of three polypeptides is markedly enhanced when K12 cells are incubated at 40.5 degrees. One of them (band B) has turned out to be a useful biochemical marker of the expression of K12 mutation since its synthesis is not affected in other ts-mutants or in hybrids in which K12 mutation is complemented. In addition, the alteration in band B synthesis is irreversible and occurs during the same stage of the cell cycle at which the mutated function is expressed.

Detection of chick rRNA in the cytoplasm of heterokaryons containing reactivated chick red cell nuclei

In order to demonstrate the presence of chick ribosomal RNA (rRNA) in the cytoplasm of heterokaryons containing reactivated chick red cell nuclei, it was necessary to increase the sensitivity of detection. The method devised took advantage of the fact that avian cells in general are capable of growing satisfactorily at higher temperatures than human cells. rRNA synthesis is temperature sensitive in human cells. The results show that reactivated chick red cell nuclei produce a significant amount of 28S rRNA, but much less than expected from autoradiographic studies. It is also clear that the temperature-sensitive function in the human cell cannot be complemented, even by a fully functional cell like a chick fibroblast.