Apple (Malus 3 domestica) represents an interesting model tree crop for studying fruit abscission. The physiological fruitlet drop occurring in this species can be easily magnified by using thinning chemicals, such as benzyladenine (BA), to obtain fruits with improved quality and marketability. Despite the economic importance of this process, the molecular determinants of apple fruitlet abscission are still unknown. In this research, BA was used to obtain fruitlet populations with different abscission potentials to be analyzed by means of a newly released 30K oligonucleotide microarray. RNAs were extracted from cortex and seed of apple fruitlets sampled over a 4-d time course, during which BA triggers fruit drop, and used for microarray hybridization. Transcriptomic profiles of persisting and abscising fruitlets were tested for statistical association with abscission potential, allowing us to identify molecular signatures strictly related to fruit destiny. A hypothetical model for apple fruitlet abscission was obtained by putting together available transcriptomic and metabolomic data. According to this model, BA treatment would establish a nutritional stress within the tree that is primarily perceived by the fruitlet cortex whose growth is blocked by resembling the ovary growth inhibition found in other species. In weaker fruits, this stress is soon visible also at the seed level, likely transduced via reactive oxygen species/sugar and hormones signaling cross talk, and followed by a block of embryogenesis and the consequent activation of the abscission zone.

The ripening physiology of detached fruit is altered by low oxygen conditions with profound effects on quality parameters. To study hypoxia-related processes and regulatory mechanisms, apple (Malus domestica, cv Granny Smith) fruit, harvested at commercial ripening, were kept at 1°C under normoxic (control) and hypoxic (0.4 and 0.8 kPa oxygen) conditions for up to 60 days. NMR analyses of cortex tissue identified eight metabolites showing significantly different accumulations between samples, with ethanol and alanine displaying the most pronounced difference between hypoxic and normoxic treatments. A rapid up-regulation of alcohol dehydrogenase and pyruvate-related metabolism (lactate dehydrogenase, pyruvate decarboxylase, alanine aminotransferase) gene expression was detected under both hypoxic conditions with a more pronounced effect induced by the lowest (0.4 kPa) oxygen concentration. Both hypoxic conditions negatively affected ACC synthase and ACC oxidase transcript accumulation. Analysis of RNA-seq data of samples collected after 24 days of hypoxic treatment identified more than 1000 genes differentially expressed when comparing 0.4 vs. 0.8 kPa oxygen concentration samples. Genes involved in cell-wall, minor and major CHO, amino acid and secondary metabolisms, fermentation and glycolysis as well as genes involved in transport, defense responses, and oxidation-reduction appeared to be selectively affected by treatments. The lowest oxygen concentration induced a higher expression of transcription factors belonging to AUX/IAA, WRKY, HB, Zinc-finger families, while MADS box family genes were more expressed when apples were kept under 0.8 kPa oxygen. Out of the eight group VII ERF members present in apple genome, two genes showed a rapid up-regulation under hypoxia, and western blot analysis showed that apple MdRAP2.12 proteins were differentially accumulated in normoxic and hypoxic samples, with the highest level reached under 0.4 kPa oxygen. These data suggest that ripe apple tissues finely and specifically modulate sensing and regulatory mechanisms in response to different hypoxic stress conditions.

A key issue in the prevention and control of Sexually Transmitted Diseases (STD) is to provide access to health centres, and in diagnosing and treating STD. The present study is aimed to assess the prevalence of sexually transmitted diseases (STDs) and Hepatitis C virus (HCV) in a population of immigrant female sex workers (FSWs). We conducted a cross sectional survey of FSWs working in Verona, North-eastern Italy. Screening test included serology for STDs [including Human Immunodeficiency Virus (HIV), syphilis and Hepatitis B virus (HBV)] and hepatitis C virus (HCV).Sixteen out of 345 (4.6%) street FSWs screened during 1999-2007 resulted positive for HIV, 12 (3.5%) were positive for HBsAg, 7 (2.0%) were positive for syphilis serological test, and 3 (0.9%) were positive for HCV. Comparison of the prevalence data between women from Africa (286/345, 82.8%) and other countries showed no statistical difference for HIV infection (R.R. 1.44; 95% CI, 0.34-6.19) and for presence of HBsAg (R.R. 2.27; 95% CI, 0.30-17.24). The positivity of syphilis serologic tests had a lower prevalence among African FSWs (mostly coming from Nigeria) than among FSWs from Eastern Europe (57/345, 16.5%). This difference was statistically significant (R.R. 0.03; 95% CI, 0.00-0.28). The prevalence of HIV infection increased with age (p=0.04, by chi2 for trend analysis), but not with the time worked as sex workers in Italy. Moreover, the presence of any of the screened infections was predictable by both age and earlier time of immigration by way of logistic multivariable regression.The prevalence of HIV and HBsAg was higher in the whole analyzed cohort compared to the general population; prevalence of syphilis was significantly higher in FSWs from Eastern Europe than in FSWs from Africa. HCV prevalence remains low among non intravenous drug abuser FSWs. The data offers a starting point to address targeted intervention that would prevent FSWs acquiring and transmitting STDs.

HighlightIn cold-stressed apple skins, the ethylene-dependent negative regulation of ROP-GAP rheostat transcripts and apoplastic H2O2 homeostasis suggests an unprecedented putative crosstalk between ROS and ethylene in abiotic stress.