An organophosphorus pesticide, ethoprophos, has been widely used in agriculture to control major insect pests. As ethoprophos is a well-known neurotoxin, its accumulation in soils and groundwater is concerning worldwide. In this study, we constructed an artificial ethoprophos-enrichment soil system, and its active concentration in soils was measured by gas chromatography on 15-days intervals during 90 days after ethoprophos treatment. Furthermore, the changes in bacterial community and microorganisms responsible for efficient bioremediation were investigated while ethoprophos was degraded in soils. From 15 to 60 days after the treatment, ethoprophos was actively degraded in soils and members of genera Collimonas and Sphingobium appeared dominantly in a natural microbial community especially in 60-days-after-treatment soil. We isolated a bacterium EP60845 from this soil sample, showing significant ethoprophos biodegradation activity in vitro. When we challenged EP60845 strain into ethoprophos-enrichment soils (250 mg/kg of soil), most ethoprophos was removed within 5-days. Phylogenetic 16S rRNA gene sequence analysis and biochemical properties by API 20GN kit demonstrated that the EP60845 strain was a novel Sphingobium sp., which could be used as an efficient ethoprophos- degrading agents for bioremediation purposes.

Riboswitches are structured RNA motifs that can directly bind specific metabolites. The binding of metabolites further regulates downstream metabolism eliminating the need for any regulatory proteins. We searched for novel bacterial vitamin B1 binding riboswitches in the metagenome of sun-dried saline soil. Soil microbial metagenomes were studied using NGS analysis. A total of approximately 50 Gb of the sequence data was obtained by Hi-seq and 454 GS FLX sequencing, and these sequences were subjected to riboswitch search. Hi-seq generated 614 contigs showing similarity to riboswitches, while 454-based sequencing generated 383 similar contigs. We matched whole metagenome contigs to local BLAST databases constructed using 91 previously known bacterial vitamin B1 thiamine pyrophosphate (TPP)-box motifs, and 11 SAM S-box motifs. Repetitive BLAST comparisons to local BLAST databases with nucleotide sequences from NGS identified 14 novel TPP-box motifs, and 7 S-box motifs respectively from the metagenome contigs. Further, RNA secondary structure analysis with public databases Rfam, and RibEx using these 21 riboswitch candidates revealed one contig, D8PYI to possess the most probable TPP-box structure. We constructed intragenic synthetic riboswitches to investigate whether the TPP-box motif region in D8PYI could harness gene expression in the presence of TPP. Construction of biosensors containing 100~400 bp fragments of D8PYI contigs, and in vivo imaging using the biosensors displayed TPP-specific changes in the expression of a green fluorescence protein reporter. In this regard, the adaptation of in silico riboswitch screening from environmental metagenomes could provide biosensors for detection of specific metabolites.

Carotenoids are the major pigment of pepper (Capsicum annuum) and tomato (Lycopersicon esulentum) which are very important foods in Korea. However the analysis of carotenoids is quite complicated because of their diversity and the presence of cis-trans isomeric forms of these compounds. The objective of this review is to collect the achievements on the field of the chromatographic separation of carotenoids in food and some vegetables, to describe and critically evaluate the techniques, And to compare the benefits and shortcomings of the various chromatographic methods such as adsorption and reversed-phase HPLC and thin-layer chromatography. HPLC equipped with ultra-violet or photodiode array detection is most often employed in routine use for the analysis of carotenoids. Here, the method to analyze carotenoids by HPLC separation after solvent extration and purification from pepper powder samples done in our laboratory is also mentioned.