Ethylene negatively regulates transcript abundance of ROP-GAP rheostat-encoding genes and affects apoplastic reactive oxygen species homeostasis in epicarps of cold stored apple fruits.

Apple (Malus×domestica Borkh) fruits are stored for long periods of time at low temperatures (1 °C) leading to the occurrence of physiological disorders. 'Superficial scald' of Granny Smith apples, an economically important ethylene-dependent disorder, was used as a model to study relationships among ethylene action, the regulation of the ROP-GAP rheostat, and maintenance of H2O2 homeostasis in fruits during prolonged cold exposure. The ROP-GAP rheostat is a key module for adaptation to low oxygen in Arabidopsis through Respiratory Burst NADPH Oxidase Homologs (RBOH)-mediated and ROP GTPase-dependent regulation of reactive oxygen species (ROS) homeostasis. Here, it was shown that the transcriptional expression of several components of the apple ROP-GAP machinery, including genes encoding RBOHs, ROPs, and their ancillary proteins ROP-GEFs and ROP-GAPs, is coordinately and negatively regulated by ethylene in conjunction with the progressive impairment of apoplastic H2O2 homeostatic levels. RNA sequencing analyses showed that several components of the known ROP- and ROS-associated transcriptional networks are regulated along with the ROP-GAP rheostat in response to ethylene perception. These findings may extend the role of the ROP-GAP rheostat beyond hypoxic responses and suggest that it may be a functional regulatory node involved in the integration of ethylene and ROS signalling pathways in abiotic stress.

Identification of the Arabidopsis RAM/MOR signalling network: adding new regulatory players in plant stem cell maintenance and cell polarization.

BACKGROUND AND AIMS: The RAM/MOR signalling network of eukaryotes is a conserved regulatory module involved in co-ordination of stem cell maintenance, cell differentiation and polarity establishment. To date, no such signalling network has been identified in plants. METHODS: Genes encoding the bona fide core components of the RAM/MOR pathway were identified in Arabidopsis thaliana (arabidopsis) by sequence similarity searches conducted with the known components from other species. The transcriptional network(s) of the arabidopsis RAM/MOR signalling pathway were identified by running in-depth in silico analyses for genes co-regulated with the core components. In situ hybridization was used to confirm tissue-specific expression of selected RAM/MOR genes. KEY RESULTS: Co-expression data suggested that the arabidopsis RAM/MOR pathway may include genes involved in floral transition, by co-operating with chromatin remodelling and mRNA processing/post-transcriptional gene silencing factors, and genes involved in the regulation of pollen tube polar growth. The RAM/MOR pathway may act upstream of the ROP1 machinery, affecting pollen tube polar growth, based on the co-expression of its components with ROP-GEFs. In silico tissue-specific co-expression data and in situ hybridization experiments suggest that different components of the arabidopsis RAM/MOR are expressed in the shoot apical meristem and inflorescence meristem and may be involved in the fine-tuning of stem cell maintenance and cell differentiation. CONCLUSIONS: The arabidopsis RAM/MOR pathway may be part of the signalling cascade that converges in pollen tube polarized growth and in fine-tuning stem cell maintenance, differentiation and organ polarity.

Increasing prevalence of HIV infection among first time clients in Italian drug treatment services - is it sexual transmission?

BACKGROUND: Over the last two decades, the proportion of people who inject drugs among newly reported HIV cases in Italy has been continuously declining. This trend is reflected in the prevalence of HIV infection among problem drug users followed in drug treatment services. We report nationwide trends in the prevalence of HIV and HCV among tested clients in charge to drug addiction services from 2005 to 2011. METHODS: Data on the prevalence of HIV and HCV among drug users from public drug treatment services across Italy were collected and analyzed for the period from 2005 to 2011. Prevalence of HIV and HCV were compared between clients returning to treatment and those entering treatment for the first time, and by gender. Due to the high percentage of missing data, the "inverse probability weight" method was used. Trends in testing uptake were also analysed. RESULTS: A significant decrease of HIV and HCV prevalence is observed among all PDUs entering treatment (from 14.7% to 11.1% and from 61.6% to 50%, respectively, in 2005-2011). By contrast, among those entering the services for the first time, after an initial decline the prevalence of HIV infection steadily increased in both sexes, from 2.2% in 2009 to 5.3% in 2011. Self-reported injecting rates in this group decreased over time, and in 2011 the proportion reporting drug injecting was lower among new clients than in people returning to services (14.5 vs. 34.4%). We also observed a progressive and significant reduction in HIV and HCV testing in drug treatment services. CONCLUSIONS: Changes in injection practice and type of drugs used, coupled with a concurrent reduction in HCV prevalence, do not support drug injection as the main explanation for an increased HIV transmission in people entering drug treatment services for the first time. While reductions in testing rates raise concerns over data quality, the possibility of increased sexual transmission needs to be considered.

The Arabidopsis thaliana Mob1A gene is required for organ growth and correct tissue patterning of the root tip.

BACKGROUND AND AIMS: The Mob1 family includes a group of kinase regulators conserved throughout eukaryotes. In multicellular organisms, Mob1 is involved in cell proliferation and apoptosis, thus controlling appropriate cell number and organ size. These functions are also of great importance for plants, which employ co-ordinated growth processes to explore the surrounding environment and respond to changing external conditions. Therefore, this study set out to investigate the role of two Arabidopsis thaliana Mob1-like genes, namely Mob1A and Mob1B, in plant development. METHODS: A detailed spatio-temporal analysis of Mob1A and Mob1B gene expression was performed by means of bioinformatic tools, the generation of expression reporter lines and in situ hybridization of gene-specific probes. To explore the function of the two genes in plant development, knock-out and knock-down mutants were isolated and their phenotype quantitatively characterized. KEY RESULTS: Transcripts of the two genes were detected in specific sets of cells in all plant organs. Mob1A was upregulated by several stress conditions as well as by abscisic acid and salicylic acid. A knock-out mutation in Mob1B did not cause any visible defect in plant development, whereas suppression of Mob1A expression affected organ growth and reproduction. In the primary root, reduced levels of Mob1A expression brought about severe defects in tissue patterning of the stem cell niche and columella and led to a decrease in meristem size. Moreover, loss of Mob1A function resulted in a higher sensitivity of root growth to abscisic acid. CONCLUSIONS: Taken together, the results indicate that arabidopsis Mob1A is involved in the co-ordination of tissue patterning and organ growth, similarly to its orthologues in other multicellular eukaryotes. In addition, Mob1A serves a plant-specific function by contributing to growth adjustments in response to stress conditions.

Signaling pathways mediating the induction of apple fruitlet abscission.

Apple (Malus × 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.

Extreme Hypoxic Conditions Induce Selective Molecular Responses and Metabolic Reset in Detached Apple Fruit.

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.

Italy's electronic health record system for opioid agonist treatment.

Electronic health record systems (EHRs) play an increasingly important role in opioid agonist treatment. In Italy, an EHR called the Multi Functional Platform (MFP) is in use in 150 opioid-agonist treatment facilities in 8 of Italy's 23 regions. This report describes MFP and presents 2010 data from 65 sites that treated 8145 patients, of whom 72.3% were treated with methadone and 27.7% with buprenorphine. Patients treated with buprenorphine compared to methadone were more likely to be male (p < .01) and younger (p < .001). Methadone compared to buprenorphine patients had a higher percentage of opioid-positive urine tests (p < .001) and longer mean length of stay (p = .004). MFP has been implemented widely in Italy and has been able to track patient outcomes across treatment facilities. In the future, this EHR system can be used for performance improvement initiatives.

Prevalence of sexually transmitted diseases and hepatitis C in a survey of female sex workers in the north-East of Italy.

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.

Characterization and evolution of the cell cycle-associated mob domain-containing proteins in eukaryotes.

The MOB family includes a group of cell cycle-associated proteins highly conserved throughout eukaryotes, whose founding members are implicated in mitotic exit and co-ordination of cell cycle progression with cell polarity and morphogenesis. Here we report the characterization and evolution of the MOB domain-containing proteins as inferred from the 43 eukaryotic genomes so far sequenced. We show that genes for Mob-like proteins are present in at least 41 of these genomes, confirming the universal distribution of this protein family and suggesting its prominent biological function. The phylogenetic analysis reveals five distinct MOB domain classes, showing a progressive expansion of this family from unicellular to multicellular organisms, reaching the highest number in mammals. Plant Mob genes appear to have evolved from a single ancestor, most likely after the loss of one or more genes during the early stage of Viridiplantae evolutionary history. Three of the Mob classes are widespread among most of the analyzed organisms. The possible biological and molecular function of Mob proteins and their role in conserved signaling pathways related to cell proliferation, cell death and cell polarity are also presented and critically discussed.