40 research outputs found
Funktionelle Charakterisierung der B-Typ Response Regulatoren von Arabidopsis thaliana
No full textCytokinins are essential for the regulation of many developmental processes in
plants. In Arabidopsis the signal transduction of cytokinins is mediated by a
multi-step His-to-Asp phospho-relay system. The B-type response regulators are
one component of this phospho-relay system. The B-type response regulators are
transcription factors that at least partially mediate the response to
cytokinin. In planta functional analysis of this protein family is hampered by
the high level of functional redundancy of its eleven members. In order to
explore the functions of the B-type response regulators and to overcome their
functional redundancy, the chimeric repressor silencing technology (CRES-T)
was employed by generating a dominant-negative version of the Arabidopsis
response regulator ARR1 (ARR1-SRDX). The 35S:ARR1-SRDX transgenic Arabidopsis
plants showed phenotypic changes reminiscent of plants with a reduced
cytokinin status, such as a strongly reduced leaf size, an enhanced root
system and larger seeds. Several bioassays showed that 35S:ARR1-SRDX plants
have an increased resistance towards cytokinin. Molecular analysis indicated
attenuation of the early transcriptional response to cytokinin. In addition, a
role for B-type ARRs in mediating crosstalk with other pathways was supported
by the resistance of 35S:ARR1-SRDX seeds to phyB-mediated inhibition of
germination by far-red light. Components downstream of the B-type ARRs were
identified by performing expression profiling using CATMA arrays. The rapid
induction of a large part of cytokinin response genes was dampened. The
transcript levels of more than 500 genes were >2.5-fold reduced in
35S:ARR1-SRDX transgenic seedlings suggesting a broad function of the B-type
ARRs. A total of 106 genes were identified as putative target genes of the
B-type ARRs, and altered expression profiles of some of these genes were
confirmed by qRT-PCR. In order to identify specific target genes of ARR1, arr1
and 35S:ARR1 transgenic plants were characterised, and their transcription
profiles were analysed. A set of 24 genes was identified as putative specific
target genes of ARR1. After finding these potential target genes by microarray
analysis, the promoter of one target gene (ARR6) was analysed to identify cis-
acting elements by promoter deletion analysis. The result of this analysis
confirmed for the first time the in planta function of a known ARR1 binding
motif. Also, a new promoter region important for the activation of the ARR6
gene was identified. The newly found 27 bp promoter region will be useful for
further studies to pinpoint the binding motif of ARR1 and/or other B-type
ARRs. In addition, attempts were made to obtain potentially relevant
information for the regulation of ARR1 activity by studying proteins that were
recognised as ARR1 interactors. In order to investigate whether the target
genes of the B-type ARRs are conserved across species and to study the
efficiency of the CRES-T in other plant species, 35S:ARR1-SRDX transgenic
tomato plants were generated and characterized. These transgenic tomato plants
also showed the cytokinin deficiency syndrome similar to Arabidopsis,
suggesting the conservation of the target genes and target gene sequences of
these transcription factors across species. Further, these transgenic tomato
plants produced seedless tomato fruits thereby indicating a role for cytokinin
in parthenocarpic fruit development. In conclusion, the suppression of
pleiotropic cytokinin activities by a dominant-negative version of a B-type
ARR indicates that this protein family is involved in mediating most, if not
all, of the cytokinin activities in Arabidopsis. The 35S:ARR1-SRDX Arabidopsis
and tomato transgenic plants and the microarray data sets comprising the
putative target genes of B-type ARRs and ARR1 are valuable tools for
investigating these functions.Cytokinine sind entscheidend an der Regulation diverser pflanzlicher
Entwicklungsprozesse beteiligt. In Arabodopsis thaliana wird die
Signaltranduktion dieses Hormons über eine mehrstufige Phosphatkaskade
vermittelt. Die so genannten Arabidopsis Response Regulatoren (ARRs) des
B-Typs sind als Transkriptionsfaktorproteine Bestandteil dieses Signalsystems
und vermitteln als Transaktivatoren die Cytokininantwort auf molekularer
Ebene. Eine hohe funktionelle Redundanz unter den 11 Mitgliedern dieser
Genfamilie erschwert jedoch funktionelle Analysen in planta. Um die Funktion
der B-Typ ARRs zu ergründen und die Redundanz innerhalb dieser Genfamilie zu
überbrücken, wurde die Chimeric Repressor Silencing Technologie (kurz CRES-T)
angewandt, durch die eine dominant-negative Repressorvariante von ARR1
generiert wurde (ARR1-SRDX). Die erzeugten transgenen 35S:ARR1-SRDX
Arabidopsis-Pflanzen wiesen phänotypische Veränderungen auf, die denen von
Pflanzen mit reduziertem Cytokiningehalt ähnelten. Dazu gehörten eine
reduzierte Blattgröße, ein verstärktes Wurzelsystem und größere Samen. Diverse
Cytokininsensitivitätstests zeigten auf eine verstärkte Cytokininresistenz der
35S:ARR1-SRDX transgenen Pflanzen. Molekulare Analysen konnten zudem eine
Abschwächung der frühen Antwort auf Cytokinin auf transkriptioneller Ebene
zeigen. Darüber hinaus wiesen 35S:ARR1-SRDX transgene Samen eine Resistenz
gegenüber der phyB-vermittelten Inhibierung der Keimung durch dunkelrotes
Licht auf, was auf eine B-Typ ARR-vermittelte Interaktion zwischen der
Cytokininsignaltransduktion und anderen Signalwegen hindeutet. Des weiteren
wurden durch Erstellung von Expressionsprofilen mittels CATMA-Arrays den B-Typ
ARRs nachgeschaltete Komponenten im Signalweg identifiziert. Die schnelle
Induktion einer Vielzahl an Cytokininantwortgenen war hierbei abgeschwächt.
Insgesamt war in 35S:ARR1-SRDX transgenen Keimlingen die relative
Transkriptabundanz von mehr als 500 Genen um mehr als 2,5- fach reduziert.
Dies deutet auf ein weites Funktionsspektrum der B-Typ ARRs hin. 106 Gene
wurden als mögliche Zielgene der B-Typ ARRs identifiziert und für einige von
ihnen wurde die veränderte Expression mittels quantitativer PCR verifiziert.
Um ARR1-spezifische Zielgene zu identifizieren, wurden neben einer molekularen
und phänotypischen Charakterisierung der Mutante arr1 und von 35S:ARR1
transgenen Pflanzen die Transkriptionsprofile beider Genotypen mittels
Microarrays analysiert. Dabei wurden insgesamt 24 Gene als potentielle
spezifische Zielgene von ARR1, u. a. ARR6, identifiziert. Der Promotor von
ARR6 wurde für Promotordeletionsanalysen verwendet, um cis-aktive Elemente zu
identifizieren. Durch diese Analysen konnte erstmals die Funktion eines zuvor
bereits bekannten ARR1 Bindemotivs in planta gezeigt werden. Des weiteren
wurde eine neue für die Aktivierung von ARR6 notwendige Region im Promotor
ermittelt. Diese 27 bp lange Region wird für weitergehende Analysen zur
Identifizierung des Bindemotivs von ARR1 und/oder weiterer B-Typ ARRs benutzt
werden. Darüber hinaus wurden mit ARR1 interagierende Proteine untersucht, um
möglicherweise relevante Informationen zur Regulation der ARR1 Aktivität zu
erhalten. Um zu überprüfen, ob die ARR1-Zielgene über die Speziesgrenze
konserviert sind und um die Effizienz der CRES-Technologie auch in anderen
Pflanzenspezies zu zeigen, wurden 35S:ARR1-SRDX transgene Tomatenpflanzen
generiert und charakterisiert. Diese Pflanzen zeigten das
Cytokinindefizienzsyndrom ähnlich dem in Arabidopsis, was auf die
Konservierung der Zielgene und Zielsequenzen dieser Transkriptionsfaktoren
über die Speziesgrenze hinaus hinweist. Das Fehlen von Samen in diesen
transgenen Pflanzen weist darüber hinaus auf eine Rolle von Cytokinin bei der
parthenocarpischen Fruchtentwicklung hin. Zusammenfassend zeigen die erzielten
Resultate, dass die pleiotropen Cytokininaktivitäten, die in der vorliegenden
Arbeit durch Verwendung einer dominanten Repressorvariante eines B-Typ ARR
unterdrückt worden waren, im wesentlichen, wenn nicht sogar vollständig, auf
die Proteinfamilie der B-Typ ARRs zurückzuführen sind. Die 35S:ARR1-SRDX
transgenen Arabidopsis-Pflanzen, die transgenen Tomatenpflanzen und die
erzeugten Microarray-Daten, die die möglichen Zielgene von ARR1 und anderer
B-Typ ARRs umfassen, sind wertvolle Hilfsmittel, um diese Funktionen weiter zu
untersuchen
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The Gene Expression Profiles of Indolent Lymphomas
No full textFollicular lymphoma is an indolent form of non-Hodgkin's lymphoma. Due to its slow growing nature, it is difficult to treat because of the inability to target slow dividing cells. Calcineurin, (CN) is a protein phosphatase (PP2B) has been shown to be involved in the apoptosis of lymphocytes in vitro cell culture system. CN is composed of a regulatory subunit CN B and a catalytic subunit CN A. Three isoforms of CN A (α, β, and γ) are expressed in various tissues. CN is the target for immunosuppressive drugs cyclosporine A and tacrolimus (FK506) because of CN's critical role in lymphocyte responses. In CNAβ knock-out mice, it was found that mice lacking this gene are prone to develop splenomegaly and lymphoma. This is because CNAβ is acting as a tumor suppressor, thus mice lacking this gene develop cancer. RNA was prepared from spleens of Cnab^(-/-) and control mice and gene expressions levels were measured by affymetrix microarray chips. Future studies will evaluate the gene expression profiles by quantitative real time PCR and immunohistochemistry to validate the expression of the candidates in lymphomagenesis. This mouse model will be the first mouse model for indolent lymphomas and has a potential for development of therapeutic interventions not only for lymphomas but also for other cancers and transplant tolerance
Highly stable and durable ZnIn2S4 nanosheets wrapped oxygen deficient blue TiO2(B) catalyst for selective CO2 photoreduction into CO and CH4
No full textDeveloping new and highly stable efficient photocatalysts is crucial for achieving high performance and selective photocatalytic CO2 conversion. In this paper, we designed a one-dimensional oxygen-deficient blue TiO2(B) (BT) catalyst for improved electron mobility and visible light accessibility. In addition, hexagonal ZnIn2S4 (ZIS) nanosheets with a low bandgap and great visible light accessibility are employed to produce effective heterostructures with BT. The synthesized materials are tested for photocatalytic conversion of CO2 into solar fuels (H2, CO and CH4). The optimized composite yields 71.6 and 10.3 & mu;mol g � 1h- 1 of CO and CH4, three and ten times greater than ZIS, respectively. When ZIS nanosheets are combined with a one-dimensional oxygen-deficient BT catalyst, improved electron mobility and visible light accessibility are achieved, charge carriers are effectively segregated, and the transfer process is accelerated, resulting in efficient CO2 reduction. The photocatalytic CO2 conversion activity of the constructed BT/ZIS heterostructures is very stable over a 10-day (240-hour) period, and CO and CH4 production rates increase linearly with time; however, as time goes on, the rates of H2 production decrease. Further, a five-time recycling test confirmed this, revealing essentially equal activity and selectivity throughout the experiment. As a result, CO2 to CO and CH4 conversion has high selectivity and longer durability. The band structure of the BT/ZIS composite is determined using Mott-Schottky measurement, diffuse
Combined drug therapeutic strategies for the effective treatment of Triple Negative Breast Cancer
No full textTNBC (Triple Negative Breast Cancer) is a subtype of breast cancer with an aggressive phenotype which shows high metastatic capability and poor prognosis. Owing to its intrinsic properties like heterogeneity, lack of hormonal receptors and aggressive phenotype leave chemotherapy as a mainstay for the treatment of TNBC. Various studies have demonstrated that chemotherapy alone or therapeutic drugs targeting TNBC pathways, epigenetic mechanisms and immunotherapy alone have not shown significant improvement in TNBC patients. On the other hand, a combination of therapeutic drugs or addition of chemotherapy with therapeutic drugs has shown substantial improvement in results and proven to be an effective strategy for TNBC treatment. This review sheds light on effective combinational drug strategies and current clinical trial status of various combinatorial drugs for the treatment of TNBC.</jats:p
Vibration diagnosis of turbomachinery coupled with induction motor
Get PDFThis paper is focusing on diagnosis for longitudinal and radial vibrations of turbomachinery coupled with induction motors. In this context, extensive field vibration measurements are conducted and analysed to identify the source of predominant vibrations on rotor bearing system in a chosen centrifugal compressor in the radial and longitudinal directions. As a first step, the measured overall vibration levels at multiple locations on bearing surface are compared with the existing ISO standard limits. These measurements showed severe longitudinal vibration values and failure of thrust collar assembly which were not considered in turbomachinery (API) design standards. The second step in diagnosis for vibration spectrum measurements are conducted both in longitudinal and radial directions during transient and steady state operations to find the vibration source and thrust collar assembly failure mechanism. This study on vibration diagnosis and analysis on turbomachinery is useful in correcting the severe longitudinal vibrations and damage control measures and corrections associated with static eccentric airgaps through motor air gap diagram
Ionic liquids-promoted addition of arylsulfinic acids to p-quinones: a green synthesis of diaryl sulfones
No full textArylsulfinic acids undergo smooth conjugate addition to p-quinones in air- and moisture-stable second generation room temperature ionic liquid [bmim]BF4 under mild conditions to produce the corresponding arylsulfonylhydroquinones in excellent yields with high selectivity. In this reaction, ionic liquid plays the dual role as the solvent and the catalyst. The quinones show enhanced reactivity in ionic liquid thereby reducing the reaction times and improving the yields significantly. The presence of ionic liquids helps to avoid the use of either acid or base catalysts for this conversion. The recovered ionic liquid was reused for four to five times with consistent activity
EVALUATION OF ANTIDIARRHOEAL ACTIVITY OF ETHANOLIC EXTRACT OF CELTIS TIMORENSIS LEAVES IN EXPERIMENTAL RATS.
Get PDFObjective: To evaluate the antidiarrhoeal activity of ethanolic extract of celtis timorensis leaves. Materials and Methods: The antidiarrhoeal activity of ethanolic extract of Celtis timorensis leaves was investigated by using castor oil induced diarrhoea, castor oil induced enteropooling, charcoal meal test models and atropine was used as a standard reference drug in all the three models. Results: The diarrhoeal severity was reduced significantly (p<0.01) by the extract by 56.85 % at 200 mg/kg and 69.48 % at 400 mg/kg, whereas 82.12 % inhibition was found for the standard drug atropine at dose 3mg/kg. In castor oil induced enteropooling, the extract at doses 200 mg/kg and 400 mg/kg, standard drug atropine showed significant reduction in the volume of the intestinal fluid (p<0.01). In the charcoal meal test, the distance travelled by charcoal meal was significantly reduced by the extract at doses 200 mg/kg and 400 mg/kg (P<0.01) when compared to the castor oil control group. The percent inhibition of charcoal meal was found to be 9.94±1.63 for control group, 15.26±2.11 at 100 mg/kg, 46.81±2.32 at 200 mg/kg, 63.61±2.61 at 400 mg/kg and 75.76±1.72 for standard group. Conclusion: The present findings concluded that the ethanolic extract of celtis timorensis leaves has a significant antidiarrhoeal activity and supports its traditional uses in herbal medicine
Nonclassical MHC-I and Japanese encephalitis virus infection: Induction of H-2Q4, H-2T23 and H-2T10
No full textNonclassical MHC Class 1b antigens differ from classical MHC class 1a antigens in having a restricted polymorphism as well as varied surface expression in different cell types. They have been hypothesized to play a role in bridging adaptive and innate immune responses.We examined the effects of JEV infection on the expression of classical MHC class 1a and nonclassical MHC class 1b genes in five different cell lines. Among the nonclassical genes, H-2Q4 was induced in H-6 hepatoma, primary astrocytes, mouse embryo fibroblasts, L929 and 3T3 cells. H-2T23 and H-2T10 genes were not induced in H-6 and 3T3, respectively, but were induced in the other cell lines examined. Both H-2Q4 encoded Qb1 and H-2T23 encoded Qa- antigens were induced on the cell surface upon JEV infection in primary astrocytes and mouse embryonic fibroblasts. Classical MHC-I genes and the genes associated with antigen presentation such as Tap1, Tap2, Tapasin, Lmp2, Lmp7 and Lmp10 as well as type 1 (\alpha/\beta) IFNs were induced in all cell lines. However, IFN\gamma was not induced. Further, induction of H-2Q4 and H-2T23 by JEV was independent of NF-\kappa B but type 1 IFN dependent while H-2T10 was dependent on NF-\kappa B and type 1 IFN independent. Thus, while classical MHC genes were induced by JEV in all cell lines tested despite high levels of constitutive expression in L929 and 3T3, nonclassical genes were not inducible in all cell lines tested and involved different mechanisms of induction
APPLICATIONS OF EDGE COLORING OF GRAPHS WITH RAINBOW NUMBERS PHENOMENA
No full textThis paper studies the Rainbow Ramsety Number for a non empty graph and the main results are 1. The Rainbow Ramsety Number of a graph F with out isolated vertices is defined if and only if F is a forest. 2. The Rainbow Ramsety Number of two graphs F1 and F2 with out isolated vertices is defined if and only if F1 is a star or F2 is a forest.
