Propolis has been used for millennia for its antimicrobial and pharmaceutical properties, whereas its use as an agricultural antifungal agent has only recently been assessed. The chemical characteristics of six ethanolic extracts of Chilean propolis (EEP-1 to EEP-6) were evaluated. The total polyphenols ranged between 7.8 and 42.3 mg mL -1 equivalents of a 2:1 pinocembrin: galangin standard, and the total flavonoid contents ranged between 4.0 and 19.7 mg mL -1 equivalents of quercetin. A high-performance liquid chromatographic (HPLC) analysis allowed the identification of caffeic acid, myricetin, quercetin, kaempferol, apigenin, pinocembrin, galangin, caffeic acid phenethyl ester (CAPE) and rutin. The EEP-3 extract was selected for additional studies based on the higher total polyphenols and flavonoids contents (42.3 and 19.7 mg mL -1 , respectively). The antifungal effects of four different concentrations (0.5, 1.0, 2.5 and 5.0 %) of EEP-3 on Alternaria alternata, Fusarium sp., Ulocladium sp., Botrytis cinerea, Penicillium expansum and Trichoderma reesei were evaluated in vitro using the agar dilution method. Although significant differences occurred among the extract concentrations, the results indicated that EEP-3 inhibited the mycelial growth of the six fungi evaluated.

BackgroundThe Copper/Zinc superoxide dismutase (Cu/ZnSOD) gene, SOD gene, was isolated from a Deschampsia antarctica Desv. by cDNA library screening. The expression of SOD gene in the leaves of D. antarctica was determined by RT-PCR and its differential expression of gene transcripts in conditions of cold and UV radiation stresses was revealed by northern blot.FindingsThe molecular characterization shows that SOD cDNA is 709 bp in length, which translates an ORF of 152 amino acids that correspond to a protein of predicted molecular mass of 15 kDa. The assay shows that the expression of SOD gene increases when D. antarctica is acclimatised to 4°C and exposed to UV radiation. These results indicate that the SOD gene of D. antarctica is involved in the antioxidative process triggered by oxidative stress induced by the conditions of environmental change in which they live.ConclusionThe present results allow us to know the characteristics of Cu/ZnSOD gene from D. antarctica and understand that its expression is regulated by cold and UV radiation.

Background: Deschampsia antarctica shows tolerance to extreme environmental factors such as low temperature, high light intensity and an increasing UV radiation as result of the Antarctic ozone layer thinning. It is very likely that the survival of this species is due to the expression of genes that enable it to tolerate high levels of oxidative stress. On that account, we planned to clone the D. antarctica Cu/ZnSOD gene into Pichia pastoris and to characterize the heterologous protein.

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Acidithiobacillus ferrivorans is a psychrotolerant acidophile capable of growing and oxidizing ferrous and sulphide substrates at low temperatures. To date, six genomes of this organism have been characterized; however, evidence of a plasmid in this species has been reported only once, whereby there is no conclusive role of the plasmids in the species. Herein, two novel plasmids of A. ferrivorans PQ33 were molecularly characterized and compared at a genomic scale. The genomes of two plasmids (12 kbp and 10 kbp) from A. ferrivorans PQ33 (NZ_LVZL01000000) were sequenced and annotated. The plasmids, named pAfPQ33-1 (NZ_CP021414.1) and pAfPQ33-2 (NZ_CP021415.1), presented 9 CDS and 13 CDS, respectively. In silico analysis showed proteins involved in conjugation (TraD, MobA, Eep and XerD), toxin-antitoxin systems (HicA and HicB), replication (RepA and DNA binding protein), transcription regulation (CopG), chaperone DnaJ, and a virulence gene (vapD). Furthermore, the plasmids contain sequences similar to phosphate-selective porins O and P and a diguanylate cyclase-phosphodiesterase protein. The presence of these genes suggests the possibility of horizontal transfer, a regulatory system of plasmid maintenance, and adhesion to substrates for A. ferrivorans species and PQ33. This is the first report of plasmids in this strain.