This review summarises the recent advances of covalent organic framework photocatalysts including structures and applications.

The capacity to fix nitrogen is widely distributed in phyla of Bacteria and Archaea but has long been considered to be absent from the Pseudomonas genus. We report here the complete genome sequencing of nitrogen-fixing root-associated Pseudomonas stutzeri A1501. The genome consists of a single circular chromosome with 4,567,418 bp. Comparative genomics revealed that, among 4,146 protein-encoding genes, 1,977 have orthologs in each of the five other Pseudomonas representative species sequenced to date. The genome contains genes involved in broad utilization of carbon sources, nitrogen fixation, denitrification, degradation of aromatic compounds, biosynthesis of polyhydroxybutyrate, multiple pathways of protection against environmental stress, and other functions that presumably give A1501 an advantage in root colonization. Genetic information on synthesis, maturation, and functioning of nitrogenase is clustered in a 49-kb island, suggesting that this property was acquired by lateral gene transfer. New genes required for the nitrogen fixation process have been identified within the nif island. The genome sequence offers the genetic basis for further study of the evolution of the nitrogen fixation property and identification of rhizosphere competence traits required in the interaction with host plants; moreover, it opens up new perspectives for wider application of root-associated diazotrophs in sustainable agriculture.genome sequencing ͉ root-associated diazotroph

The objective of this study was to establish baseline concentrations for 15 potentially toxic elements (Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, and Zn) based on 448 representative Florida surface soils using microwave assisted HNOrHCI-HF digestion. Baseline concentrations of those elements were (mg kg-I): Ag 0.07-2.50, As 0.02-7.01, Ba 1.67-112, Be 0.04-4.15, Cd 6-0.33, Cr 0.89-80.7, Cu 0.22-21.9, Hg 0.00075--0.0396, Mo 0.13-6.76, Ni 1.70-48.5, Pb 0.69-42.0, Sb 0.06-0.79, Se 0.01-1.11, and Zn 0.89-29.6, respectively. Upper baseline values for most elements corresponded with these reported in literature, except Ba, Hg, Mn, Sb, and Zn, which were 3 to 23 times lower. Soil properties, including pH, organic carbon (OC), particle size, cation-exchange capacity (CEC), available water, extractable base, extractable acidity, total Ca, Mg, P, K, Fe, and AI concentrations, were related to metal concentrations using factorial analysis. Eight factors were identified (total Fe and AI, CEC, pH, clay, OC, total Ni and Mo, total Sb and Pb, and total Hg) and accounted for 87% of the total variance, suggesting that metal concentrations were primarily controUed by soil compositions. Multiple regression of elemental concentrations against total Fe, total AI, clay, OC, CEC, and pH was significant for aU elements. Partial correlation coefficients indicated that total Fe and/or AI explained most of the variance for Mn, Ni, Ba, Be, Hg, As, Cd, Cr, Cu, Mo, Pb, and Zn concentrations. Most of the variance in Se was related to clay, whereas those of Ag and Sb related to clay and total AI.