Physicochemical and biochemical characterization of transgenic papaya modified for protection against Papaya ringspot virus

[Sleep in adolescents of different socioeconomic status: a systematic review]

OBJECTIVE

To analyze the sleep characteristics in adolescents from different socioeconomic levels.

DATA SOURCE

Original studies found in the Medline/PubMed and SciELO databases without language and period restrictions that analyzed associations between sleep variables and socioeconomic indicators. The initial search resulted in 99 articles. After reading the titles and abstracts and following inclusion and exclusion criteria, 12 articles with outcomes that included associations between sleep variables (disorders, duration, quality) and socioeconomic status (ethnicity, family income, and social status) were analyzed.

DATA SYNTHESIS

The studies associating sleep with socioeconomic variables are recent, published mainly after the year 2000. Half of the selected studies were performed with young Americans, and only one with Brazilian adolescents. Regarding ethnic differences, the studies do not have uniform conclusions. The main associations found were between sleep variables and family income or parental educational level, showing a trend among poor, low social status adolescents to manifest low duration, poor quality of sleeping patterns.

CONCLUSIONS

The study found an association between socioeconomic indicators and quality of sleep in adolescents. Low socioeconomic status reflects a worse subjective perception of sleep quality, shorter duration, and greater daytime sleepiness. Considering the influence of sleep on physical and cognitive development and on the learning capacity of young individuals, the literature on the subject is scarce. There is a need for further research on sleep in different realities of the Brazilian population.

Compositional equivalency of RNAi-mediated virus-resistant transgenic soybean and its nontransgenic counterpart

RNA silencing or RNA interference (RNAi), which is triggered by double-stranded RNA (dsRNA), is an evolutionarily conserved process that is active in a wide variety of eukaryotic organisms. Engineering plants with hairpin construct in which the viral gene is arranged in inverted repeats (IR) renders plants resistant to plant virus infection. However, there is no report on whether biologically important changes occurred by the insertion of IR, which confer transgenic plants virus resistance. In the present study, the compositions of virus-resistant transgenic soybean seeds developed by insertion of three short IRs, each containing the specific, highly conserved sequences derived from one virus, were compared with those of nontransgenic counterparts by applying the principle of substantial equivalence to determine whether significant undesirable biological changes occurred by IR insertion. The results revealed that the nutrient components as well as antinutrient contents of these virus-resistant soybean lines are substantially equivalent to those of the nontransgenic counterparts, and the majority of the measured amounts of nutritional components and antinutrient contents are well within the range of values reported for other commercial soybean lines. The results imply that no biologically important changes occurred by the insertion of IRs in the RNAi-mediated virus-resistant transgenic soybeans. The results can serve as baseline information for developing RNAi-mediated transgenic soybean cultivars or other crops with broader spectrum virus resistance.

Gene technology for papaya ringspot virus disease management

Papaya (Carica papaya) is severely damaged by the papaya ringspot virus (PRSV). This review focuses on the development of PRSV resistant transgenic papaya through gene technology. The genetic diversity of PRSV depends upon geographical distribution and the influence of PRSV disease management on a sequence of PRSV isolates. The concept of pathogen-derived resistance has been employed for the development of transgenic papaya, using a coat protein-mediated, RNA-silencing mechanism and replicase gene-mediated transformation for effective PRSV disease management. The development of PRSV-resistant papaya via post-transcriptional gene silencing is a promising technology for PRSV disease management. PRSV-resistant transgenic papaya is environmentally safe and has no harmful effects on human health. Recent studies have revealed that the success of adoption of transgenic papaya depends upon the application, it being a commercially viable product, bio-safety regulatory issues, trade regulations, and the wider social acceptance of the technology. This review discusses the genome and the genetic diversity of PRSV, host range determinants, molecular diagnosis, disease management strategies, the development of transgenic papaya, environmental issues, issues in the adoption of transgenic papaya, and future directions for research.

Complete genome of Hainan papaya ringspot virus using small RNA deep sequencing

Small RNA deep sequencing allows for virus identification, virus genome assembly, and strain differentiation. In this study, papaya plants with virus-like symptoms collected in Hainan province were used for deep sequencing and small RNA library construction. After in silicon subtraction of the papaya sRNAs, small RNA reads were used to in the viral genome assembly using a reference-guided, iterative assembly approach. A nearly complete genome was assembled for a Hainan isolate of papaya ringspot virus (PRSV-HN-2). The complete PRSV-HN-2 genome (accession no.: KF734962) was obtained after a 15-nucleotide gap was filled by direct sequencing of the amplified genomic region. Direct sequencing of several random genomic regions of the PRSV isolate did not find any sequence discrepancy with the sRNA-assembled genome. The newly sequenced PRSV-HN-2 genome shared a nucleotide identity of 96 and 94 % to that of the PRSV-HN (EF183499) and PRSV-HN-1 (HQ424465) isolates, and together with these two isolates formed a new PRSV clade. These data demonstrate that the small RNA deep sequencing technology provides a viable and rapid mean to assemble complete viral genomes in plants.