A regulatory gene, cfxR, involved in the carbon dioxide assimilation of Alcaligenes eutrophus H16 has been characterized through the analysis of mutants. The function of cfxR is required for the expression of two cfx operons that comprise structural genes encoding Calvin cycle enzymes. CfxR (34.8 kDa) corresponds with an open reading frame of 954 bp, with a translational initiation codon 167 bp upstream of the chromosomal cfx operon. The cfx operon and cfxR are transcribed divergently. The N-terminal sequence of CfxR is very similar to those of bacterial regulatory proteins belonging to the LysR family. Heterologous expression of cfxR in Escherichia coli was achieved using the pT7-7 system. Mobility shift experiments demonstrated that CfxR is a DNA-binding protein with a target site upstream of both the chromosomal and the plasmid-encoded cfx operons.

The cyanobacterium Synechococcus PCC7942 was transformed with various carotenogenic genes, and the resulting transformants either accumulated higher amounts of ␤-carotene and zeaxanthin or showed a shift in the carotenoid pattern toward the formation of zeaxanthin. These transformants were exposed to ultraviolet-B (UV-B) radiation, and the degradation of phycobilins, the inactivation of photosynthetic oxygen evolution, and the activity of photosystem II were determined. In the genetically modified cells, the influence on destruction of phycobilins was negligible. However, protection of photosynthetic reactions against UV-B damage was observed and was dependent on the carotenoid concentrations in the different transformants. Furthermore, it was shown that endogenous zeaxanthin is more effective than ␤-carotene. Our results suggest that carotenoids exert their protective function as antioxidants to inactivate UV-B-induced radicals in the photosynthetic membrane.

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Safety and efficacy benefits of DCS over BMS were maintained for 2 years in high bleeding risk patients. Rates of major bleeding and coronary thrombotic events were no different and were associated with a substantial and comparable mortality risk. (A Prospective Randomized Comparison of the BioFreedom Biolimus A9 Drug Coated Stent Versus the Gazelle Bare Metal Stent in Patients With High Risk of Bleeding [LEADERS FREE]; NCT01623180).

Three transposon Tn5-induced mutants deficient in autotrophic CO2 fixation were isolated from a megaplasmid pHG1-cured strain of Alcaligenes eutrophus H16. Their phenotypes were initially characterized by their ability to form both key enzymes of the Calvin cycle, ribulose-1,5-bisphosphate carboxylase (Rubisco) and phosphoribulokinase (PRK). Since the transposon insertions were at different sites within the chromosomal cluster of cfx genes encoding Calvin cycle enzymes, the individual mutants showed different inactivation patterns for Rubisco and PRK synthesis. These data together with already known sequence data and the arrangement of cfx genes suggested that the Rubisco, fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase and PRK genes are constituents of the same operon. This was further confirmed by trans complementation analyses which indicated that the very similarly organized pHG1-encoded cfx genes additionally present in wild-type strain H16 are functional and also form a common operon. Each operon may also include a glyceraldehyde-3-phosphate dehydrogenase gene. Thus, the duplicated cfx operons of A. eutrophus H16 are large transcriptional units comprising at least about 8 kilobase pairs (kb) and possibly as much as 11 kb.