ABSTRACT
The Northern region of the Antarctic Peninsula constitutes the area with the highest human presence in West Antarctica. The human presence, with all the activities associated such as logistic, scientific and tourism operations, represents a potential risk of chemical pollution with both, organic and inorganic contaminants. Under these conditions knowledge about the presence and levels of the main persistent organic pollutants (POPs) is essential to evaluate the environmental status of this ecologically relevant and sensitive area. In this work, which complements our previous study regarding trace elements, we performed the first regional-scale monitoring of 24 PAHs (16 of them included in EPA list of primary pollutant), and organotin compounds (OTCs:TBT, DBT and MBT) in surface sediment from 68 sites comprising six different areas in Maxwell Bay, southeast coast of 25 de Mayo (King George) Island. POPs were quantified in surface sediment samples (20-30 m depth) obtained during two summer Antarctic expeditions by gas chromatography-mass spectrometry (GC-MS). The two most anthropized areas (South Fildes and Potter Cove) showed moderated evidence of pollution for PAHs and OTC. In some sampling sites the concentration of total PAHs was higher than 100 ng/g dw, while TBT was detected in only five samples, two of them located in Potter Cove (ranged between 14 and 18 ng/g dw), and three, located in South Fildes area (ranged between 118 and 416 ng/g dw). Although POPs contamination was evidenced in some samples close to scientific stations, a pollution pattern was not clearly identified.
ABSTRACT
We describe the cloning of a cDNA encoding tomato alcohol dehydrogenase 2 (Adh2) by screening plasmid cDNA clones in phage plaques. A cDNA library constructed in a plasmid vector containing a unique SstI site at the 5' end of the cDNA insert was transferred into the SstI site of the lacZ gene of phage lambda Charon16, and screened by anti-Adh2 antibody to identify reactive plaques. Plasmid cDNA clones were recovered by SstI digestion, ligation, and transformation from phage minipreps for subsequent characterization. This system preserves the original plasmid library for subsequent screening with nucleic acid probes to identify full-length, multiple independent, or related cDNA clones not subject to the selection pressure of phage growth or lysogeny, or negative antibody reactivity. Thirty-two cDNA clones were identified with polyclonal antiserum to Adh2. Three of these reacted with monoclonal anti-Adh2 and only those three hybridized to maize adh1 sequence. One of these cDNAs, Adh31, was further characterized as encoding Adh2 by hybrid-selected translation and high sequence homology with the maize adh1 gene.
