Search

The development of organic electro-optic materials with ultrahigh electro-optic coefficients and high long-term alignment stability is the most challenging topic in this field. Next-generation crosslinkable nonlinear optical chromophore molecular glasses were developed to address this problem. A highly stable EO system including crosslinkable binary chromophores QLD1 and QLD2 or crosslinkable single chromophore QLD3 and multichromophore QLD4 with large hyperpolarizability was synthesized using tetrahydroquinoline as the donor. When the temperature continues to rise after poling, the chromophores modified with anthracene and acrylate can undergo Diels-Alder crosslinking reaction to fix the oriented chromophores through chemical bonds. After crosslinking, the QLD1/QLD2 and QLD2/QLD4 films achieved very high maximum

The growth and tolerance of Kluyveromyces marxianus at high temperatures decreased significantly in the synthetic medium (SM), which is commonly used in industrial fermentations. After 100 days of adaptive laboratory evolution, a strain named KM234 exhibited excellent tolerance at a high temperature, without loss of its growth ability at a moderate temperature. Transcriptomic analysis revealed that the KM234 strain decreased the expression of the ammonium (NH

Background Using yeast fermentation to produce bioethanol, is an economic and renewable way to tackle the rapid increase in fuel consumption. Faster cell growth rate guarantees the superior result of fermentation course. The “non-conventional” yeast Kluyveromyces marxianus is the known fastest-growing eukaryote on the earth. Although its wide application in industry, the molecular mechanisms for its fast growth have seldom been discovered.Results We first carried out a comparative genome content analysis for K. marxianus evolution in Saccharomycetaceae and identified the gain/lost genes as well as highly copied genes during K. marxianus speciation. Then RNA-seq analyses for K. marxianus and S. cerevisiae at different time points along cultivation were performed, to infer the function of K. marxianus-specific genes and to find out the difference in homologous gene expression patterns between the two species. RNA-seq results were further validated with RT-qPCR analysis. Genome content analysis shows the highly intense events of genes’ gain/loss happened at the occurrence of Saccharomycetaceae and Kluyveromyces, and K. marxianus has particularly high copy numbers of genes participating in iron transport and biotin biosynthesis. The RNA-seq analysis reveals 40% of K. marxianus-specific genes were up-regulated and may participate in glucose transport and mitochondrial function. Furthermore, compared to S. cerevisiae, K. marxianus has developed two features in homologous gene expressions to ensure its fast growth: (1) enhanced fundamental expressions of TCA cycle and respiratory chain genes at the beginning of cultivation; (2) tightly co-up-regulated expressions of respiratory chain, F0F1 ATPase, and glucose transporter genes at its fastest growth phase. Those co-expressions are mainly ascribed to the higher number of significant motifs in the upstream sequences of involved genes in K. marxianus than in S. cerevisiae, indicating the importance of transcriptional network remodelling during evolution.Conclusions This study gives insights into the possible mechanisms of K. marxianus’ fast growth trait, via efficiently supplying sufficient energy for cell growth, meanwhile reinforcing glucose transport to guarantee the competition for environmental resources. Our findings present a theoretical support for K. marxianus’ prospective application in industry, and give clues for further rational construction of fast-growing yeast strains.

Three novel chromophores B-D have been synthesized based on thiophene derivatived donors, including 5-(methyl(phenyl)amino)thiophene 5-(bis(4-methoxyphenyl)amino)thiophene 5-((4-methoxyphenyl)(methyl)amino)thiophene groups respectively, with the same isophorone-derived bridge and tricyanovinyldihydrofuran (TCF) acceptors. A new strategy was proposed to improve the electron donating ability of the chromophore, thienyl groups were explored as a replacement for the phenyl unit in the donor part of the chromophore. Density functional theory calculations suggested that the first hyperpolarizability of (arylamino) thiophene donor-containing chromophore B-D is about 20% higher than that of 4-(dialkylamino) phenyl counterpart chromophore A. At least 50% enhancement in bulk nonlinearity (r33) is realized as the donor subunits were changed from alkylaniline to (arylamino) thiophene donors. Polymeric thin films doped with 25 wt% chromophore B-D have been poled to afford large r33 values of 131, 143 and 138 p.m./V at 1.31 μm, respectively, which is much higher than the EO activity of chromophore A (88 pm/V).