Acetobacter pasteurianus, an obligately oxidative bacterium, is the first organism shown to utilize pyruvate decarboxylase (PDC) as a central enzyme for oxidative metabolism. In plants, yeast, and other bacteria, PDC functions solely as part of the fermentative ethanol pathway. During the growth of A. pasteurianus on lactic acid, the central intermediate pyruvate is cleaved to acetaldehyde and CO(2) by PDC. Acetaldehyde is subsequently oxidized to its final product, acetic acid. The presence of the PDC enzyme in A. pasteurianus was confirmed by zymograms stained for acetaldehyde production, enzyme assays using alcohol dehydrogenase as the coupling enzyme, and by cloning and characterization of the pdc operon. A. pasteurianus pdc was also expressed in recombinant Escherichia coli. The level of PDC activity was regulated in response to growth substrate, highest with lactic acid and absent with mannitol. The translated PDC sequence (548 amino acids) was most similar to that of Zymomonas mobilis, an obligately fermentative bacterium. A second operon ( aldA) was also found which is transcribed divergently from pdc. This operon encodes a putative aldehyde dehydrogenase (ALD2; 357 amino acids) related to class III alcohol dehydrogenases and most similar to glutathione-dependent formaldehyde dehydrogenases from alpha-Proteobacteria and Anabeana azollae. 相似文献
Shoot tips, cotyledonary nodes and hypocotyls of chickpea (Cicer arietinum L.) were grown on 3 media: plant induction medium
(PIM), callus induction medium (CIM), and shoot induction medium (SIM). Maximum growth and differentiation was seen in PIM,
whereas minimum was observed in CIM. Shoot tips which differentiated to multiple shoots evolved negligible amounts of ethylene.
Maximum ethylene evolution was recorded by hypocotyls in PIM. Ethylene appears to have stimulatory effect on shoot bud differentiation
in cotyledonary nodes. But in hypocotyls, increased ethylene inhibited growth and differentiation. Calli on media containing
only auxin (PIM) evolved significantly more ethylene, whereas those on media with cytokinin (SIM) evolved more methane. Callus
forming explants like cotyledonary nodes and hypocotyls evolve more ethylene than shoot tips.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
Molecular Biology Reports - RUNX1T1 is extensively studied in the context of AML1-RUNX1T1 fusion protein in acute myeloid leukemia. Little is known about the function of RUNX1T1 itself, although... 相似文献
Sorghum is largely grown for food, fodder and for biofuel production in semi-arid regions where the drought or high temperature or their combination co-occur. Plant microRNAs (miRNAs) are integral to the gene regulatory networks that control almost all biological processes including adaptation to stress conditions. Thus far, plant miRNA profiles under separate drought or heat stresses have been reported but not under combined drought and heat. In this study, we report miRNA profiles in leaves of sorghum exposed to individual drought or heat or their combination. Approximately 29 conserved miRNA families represented by 80 individual miRNAs, 26 families represented by 47 members of less conserved or sorghum-specific miRNA families as well as 8 novel miRNA families have been identified. Of these, 25 miRNAs were found to be differentially regulated in response to stress treatments. The comparative profiling revealed that the miRNA regulation was stronger under heat or combination of heat and drought compared to the drought alone. Furthermore, using degradome sequencing, 48 genes were confirmed as targets for the miRNAs in sorghum. Overall, this study provides a framework for understanding of the miRNA-guided gene regulations under combined stresses.
International Journal of Peptide Research and Therapeutics - Initial phase of COVID-19 infection is associated with the binding of viral spike protein S1 receptor binding domain (RBD) with the host... 相似文献