@article{KhanAlMandharyAlSutietal.2004, author = {Khan, Muhammad S. and Al-Mandhary, Muna R. A. and Al-Suti, Mohammed K. and Al-Battashi, Fathiya R. and Al-Saadi, Sultan and Bjernemose, Jens K. and Mahon, Mary F. and Chawdhury, Nazia and Yonus, Muhammad and K{\"o}hler, Anna and Teat, Simon J. and Marseglia, Elizabeth A. and Tedesco, Emilio and Feeder, Neil and Ahrens, Birte and Raithby, Paul R.}, title = {Synthesis, characterisation and optical spectroscopy of platinum(II) di-ynes and poly-ynes incorporating condensed aromatic spacers in the backbone}, issn = {1477-9226}, doi = {10.1039/B405070C}, year = {2004}, language = {en} } @article{UdDinRaufGhafooretal.2016, author = {Ud-Din, Aziz and Rauf, Mamoona and Ghafoor, S. and Khattak, M. N. K. and Hameed, M. W. and Shah, H. and Jan, S. and Muhammad, K. and Rehman, A. and Inamullah,}, title = {Efficient use of artificial micro-RNA to downregulate the expression of genes at the post-transcriptional level in Arabidopsis thaliana}, series = {Genetics and molecular research}, volume = {15}, journal = {Genetics and molecular research}, publisher = {FUNPEC}, address = {Ribeirao Preto}, issn = {1676-5680}, doi = {10.4238/gmr.15027439}, pages = {11}, year = {2016}, abstract = {Micro-RNAs are cellular components regulating gene expression at the post-transcription level. In the present study, artificial micro-RNAs were used to decrease the transcript level of two genes, AtExpA8 (encoding an expansin) and AHL25 (encoding an AT-hook motif nuclear localized protein) in Arabidopsis thaliana. The backbone of the Arabidopsis endogenous MIR319a micro-RNA was used in a site-directed mutagenesis approach for the generation of artificial micro-RNAs targeting two genes. The recombinant cassettes were expressed under the control of the CaMV 35S promoter in individual A. thaliana plants. Transgenic lines of the third generation were tested by isolating total RNA and by subsequent cDNA synthesis using oligo-dT18 primers and mRNAs as templates. The expression of the two target genes was checked through quantitative realtime polymerase chain reaction to confirm reduced transcript levels for AtExpA8 and AHL25. Downregulation of AtExpA8 resulted in the formation of short hypocotyls compared with those of the wild-type control in response to low pH and high salt concentration. This technology could be used to prevent the expression of exogenous and invading genes posing a threat to the normal cellular physiology of the host plant.}, language = {en} } @article{ZhangHayerAlSutietal.2006, author = {Zhang, Ning and Hayer, Anna and Al-Suti, Mohammed K. and Al-Belushi, Rayya A. and Khan, Muhammad S. and K{\"o}hler, Anna}, title = {The effect of delocalization on the exchange energy in meta- and para-linked Pt-containing carbazole polymers and monomers}, doi = {10.1063/1.2200351}, year = {2006}, abstract = {A series of novel platinum-containing carbazole monomers and polymers was synthesized and fully characterized by UV-VIS absorption, luminescence, and photoinduced absorption studies. In these compounds, a carbazole unit is incorporated into the main chain via either a para- or a meta-linkage. We discuss the effects of linkage and polymerization on the energy levels of S-1, T-1, and T-n. The S-1-T-1 splitting observed for the meta-linked monomer (0.4 eV) is only half of that in the para-linked monomer (0.8 eV). Upon polymerization, the exchange energy in the para- linked compound reduces, yet still remains larger than in the meta-linked polymer. We attribute the difference in exchange energy to the difference in wave function overlap between electron and hole in these compounds. (c) 2006 American Institute of Physics}, language = {en} } @article{HayerKoehlerArisietal.2004, author = {Hayer, Anna and K{\"o}hler, Anna and Arisi, E. and Bergenti, I. and Dediu, A. and Taliani, C. and Al-Suti, Mohammed K. and Khan, Muhammad S.}, title = {Polymer light-emitting diodes with spin-polarised charge injection.}, issn = {0379-6779}, year = {2004}, language = {en} } @article{YangVardenyKoehleretal.2004, author = {Yang, C. and Vardeny, Z. V. and K{\"o}hler, Anna and Wohlgenannt, M. and Al-Suti, Mohammed K. and Khan, Muhammad S.}, title = {Spectroscopic study of spin-dependent exciton formation rates in pi-conjugated semiconductors : Comparison with electroluminescence techniques}, year = {2004}, abstract = {It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We employed the technique of optically detected magnetic resonance to measure the spin-dependent exciton formation rates in films of a polymer and corresponding monomer, and explore the relation between the formation rates and the actual singlet-to-triplet ratio measured previously in OLEDs. We found that the spin-dependent exciton formation rates can indeed quantitatively explain the observed exciton yields, and that singlet formation rates and yields are significantly enhanced only in polymer OLEDs, but not in OLEDs made from the corresponding monomer}, language = {en} } @article{DeviAlSutiDoscheetal.2008, author = {Devi, Lekshmi Sudha and Al-Suti, Mohammed K. and Dosche, Carsten and Khan, Muhammad S. and Friend, Richard H. and K{\"o}hler, Anna}, title = {Triplet energy transfer in conjugated polymers : I. Experimental investigation of a weakly disordered compound}, year = {2008}, abstract = {Efficient triplet exciton emission has allowed improved operation of organic light-emitting diodes (LEDs). To enhance the device performance, it is necessary to understand what governs the motion of triplet excitons through the organic semiconductor. Here, we have investigated triplet diffusion using a model compound that has weak energetic disorder. The Dexter-type triplet energy transfer is found to be thermally activated down to a transition temperature T- T, below which the transfer rate is only weakly temperature dependent. We show that above the transition temperature, Dexter energy transfer can be described within the framework of Marcus theory. We suggest that below T-T, the nature of the transfer changes from phonon-assisted hopping to quantum-mechanical tunneling. The lower electron-phonon coupling and higher electronic coupling in the polymer compared to the monomer results in an enhanced triplet diffusion rate.}, language = {en} } @article{EngqvistSchmitzGertzmannetal.2015, author = {Engqvist, Martin K. M. and Schmitz, Jessica and Gertzmann, Anke and Florian, Alexandra and Jaspert, Nils and Arif, Muhammad and Balazadeh, Salma and M{\"u}ller-R{\"o}ber, Bernd and Fernie, Alisdair R. and Maurino, Veronica G.}, title = {GLYCOLATE OXIDASE3, a Glycolate Oxidase Homolog of Yeast L-Lactate Cytochrome c Oxidoreductase, Supports L-Lactate Oxidation in Roots of Arabidopsis}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {169}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, number = {2}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {0032-0889}, doi = {10.1104/pp.15.01003}, pages = {1042 -- 1061}, year = {2015}, abstract = {In roots of Arabidopsis (Arabidopsis thaliana), L-lactate is generated by the reduction of pyruvate via L-lactate dehydrogenase, but this enzyme does not efficiently catalyze the reverse reaction. Here, we identify the Arabidopsis glycolate oxidase (GOX) paralogs GOX1, GOX2, and GOX3 as putative L-lactate-metabolizing enzymes based on their homology to CYB2, the L-lactate cytochrome c oxidoreductase from the yeast Saccharomyces cerevisiae. We found that GOX3 uses L-lactate with a similar efficiency to glycolate; in contrast, the photorespiratory isoforms GOX1 and GOX2, which share similar enzymatic properties, use glycolate with much higher efficiencies than L-lactate. The key factor making GOX3 more efficient with L-lactate than GOX1 and GOX2 is a 5- to 10-fold lower Km for the substrate. Consequently, only GOX3 can efficiently metabolize L-lactate at low intracellular concentrations. Isotope tracer experiments as well as substrate toxicity tests using GOX3 loss-of-function and overexpressor plants indicate that L-lactate is metabolized in vivo by GOX3. Moreover, GOX3 rescues the lethal growth phenotype of a yeast strain lacking CYB2, which cannot grow on L-lactate as a sole carbon source. GOX3 is predominantly present in roots and mature to aging leaves but is largely absent from young photosynthetic leaves, indicating that it plays a role predominantly in heterotrophic rather than autotrophic tissues, at least under standard growth conditions. In roots of plants grown under normoxic conditions, loss of function of GOX3 induces metabolic rearrangements that mirror wild-type responses under hypoxia. Thus, we identified GOX3 as the enzyme that metabolizes L-lactate to pyruvate in vivo and hypothesize that it may ensure the sustainment of low levels of L-lactate after its formation under normoxia.}, language = {en} }