Influence of nanoliposomes incorporation on properties of film forming dispersions and films based on corn starch and sodium caseinate

The incorporation of potentially antimicrobial volatile compounds (orange essential oil and limonene) into soy and rapeseed nanoliposomes was carried out by encapsulating them trough sonication of their aqueous dispersions. Nanoliposomes were added to starch-sodium caseinate (50:50) film forming dispersions, which were dried to obtain films without losses of the volatile compounds. Structural, mechanical and optical properties of the films were analysed, as well as their antimicrobial activity against Listeria monocytogenes. The addition of liposomes in the polymeric matrix supposed a decrease of the mechanical resistance and extensibility of the films. The natural colour of lecithin conferred a loss of lightness, a chroma gain and a redder hue to the films, which were also less transparent than the control one, regardless the lecithin and volatile considered. The possible antimicrobial activity of the films containing orange essential oil or limonene was not observed, which could be due to their low antilisterial activity or to the inhibition effect of the encapsulation which difficult their release from the matrix.Jiménez Marco, A.; Sánchez González, L.; Desobry, S.; Chiralt Boix, MA.; Arab Tehrany, E. (2014). Influence of nanoliposomes incorporation on properties of film forming dispersions and films based on corn starch and sodium caseinate. Food Hydrocolloids. 35:159-169. doi:10.1016/j.foodhyd.2013.05.006S1591693

Preferential Occupancy of R2 Retroelements on the B Chromosomes of the Grasshopper Eyprepocnemis plorans

R2 non-LTR retrotransposons exclusively insert into the 28S rRNA genes of their host, and are expressed by co-transcription with the rDNA unit. The grasshopper Eyprepocnemis plorans contains transcribed rDNA clusters on most of its A chromosomes, as well as non-transcribed rDNA clusters on the parasitic B chromosomes found in many populations. Here the structure of the E. plorans R2 element, its abundance relative to the number of rDNA units and its retrotransposition activity were determined. Animals screened from five populations contained on average over 12,000 rDNA units on their A chromosomes, but surprisingly only about 100 R2 elements. Monitoring the patterns of R2 insertions in individuals from these populations revealed only low levels of retrotransposition. The low rates of R2 insertion observed in E. plorans differ from the high levels of R2 insertion previously observed in insect species that have many fewer rDNA units. It is proposed that high levels of R2 are strongly selected against in E. plorans, because the rDNA transcription machinery in this species is unable to differentiate between R2-inserted and uninserted units. The B chromosomes of E. plorans contain an additional 7,000 to 15,000 rDNA units, but in contrast to the A chromosomes, from 150 to over 1,500 R2 elements. The higher concentration of R2 in the inactive B chromosomes rDNA clusters suggests these chromosomes can act as a sink for R2 insertions thus further reducing the level of insertions on the A chromosomes. These studies suggest an interesting evolutionary relationship between the parasitic B chromosomes and R2 elements.This study was supported by grants from the Spanish Ministerio de Ciencia y Tecnología (CGL2009-11917) and Plan Andaluz de Investigacion (CVI-6649), and was partially performed by FEDER funds and a grant from the National Institutes of Health (GM42790)

Deep sequencing of the Mexican avocado transcriptome, an ancient angiosperm with a high content of fatty acids

Background: Avocado (Persea americana) is an economically important tropical fruit considered to be a good source of fatty acids. Despite its importance, the molecular and cellular characterization of biochemical and developmental processes in avocado is limited due to the lack of transcriptome and genomic information. Results: The transcriptomes of seeds, roots, stems, leaves, aerial buds and flowers were determined using different sequencing platforms. Additionally, the transcriptomes of three different stages of fruit ripening (pre-climacteric, climacteric and post-climacteric) were also analyzed. The analysis of the RNAseqatlas presented here reveals strong differences in gene expression patterns between different organs, especially between root and flower, but also reveals similarities among the gene expression patterns in other organs, such as stem, leaves and aerial buds (vegetative organs) or seed and fruit (storage organs). Important regulators, functional categories, and differentially expressed genes involved in avocado fruit ripening were identified. Additionally, to demonstrate the utility of the avocado gene expression atlas, we investigated the expression patterns of genes implicated in fatty acid metabolism and fruit ripening. Conclusions: A description of transcriptomic changes occurring during fruit ripening was obtained in Mexican avocado, contributing to a dynamic view of the expression patterns of genes involved in fatty acid biosynthesis and the fruit ripening process