Biosafety considerations of RNAi-mediated virus resistance in fruit-tree cultivars and in rootstock

A major application of RNA interference (RNAi) is envisaged for the production of virus-resistant transgenic plants. For fruit trees, this remains the most, if not the only, viable option for the control of plant viral disease outbreaks in cultivated orchards, due to the difficulties associated with the use of traditional and conventional disease-control measures. The use of RNAi might provide an additional benefit for woody crops if silenced rootstock can efficiently transmit the silencing signal to non-transformed scions, as has already been demonstrated in herbaceous plants. This would provide a great opportunity to produce non-transgenic fruit from transgenic rootstock. In this review, we scrutinise some of the concerns that might arise with the use of RNAi for engineering virus-resistant plants, and we speculate that this virus resistance has fewer biosafety concerns. This is mainly because RNAi-eliciting constructs only express small RNA molecules rather than proteins, and because this technology can be applied using plant rootstock that can confer virus resistance to the scion, leaving the scion untransformed. We discuss the main biosafety concerns related to the release of new types of virus-resistant plants and the risk assessment approaches in the application of existing regulatory systems (in particular, those of the European Union, the USA, and Canada) for the evaluation and approval of RNAi-mediated virus-resistant plants, either as transgenic varieties or as plant virus resistance induced by transgenic rootstock.     

A barcode analysis of the genus Lobophora (Dictyotales,Phaeophyceae) in the western Atlantic Ocean with four novel species and the epitypification of L. variegata (J.V. Lamouroux) E.C. Oliveira

In the western Atlantic Ocean, the brown algal genus Lobophora is currently represented by a single species, L. variegata, with a type locality designated by Lamouroux as ‘Antilles’. In this study, we used molecular-assisted alpha taxonomy (MAAT) to assess species diversity of Lobophora in Bermuda, the Florida Keys, St. Croix and Guadeloupe (Lesser Antilles). Using cox1 and cox3 sequences as barcode markers, five species of Lobophora, four of them novel, were delineated, all previously having been identified in the area as L. variegata. Our morphological and habitat studies, made possible by abundant sampling, have revealed unique characters for each of these western Atlantic species, including distinct cellular arrangements, as well as different depth ranges for certain species. Observations made from Lamouroux’s holotype of Dictyota variegata (= Lobophora variegata) allowed us to assess the anatomy of this species, which enabled us to easily align this early taxon to one of our genetic species from the western Atlantic. As the type was unavailable for genetic analysis, we selected a recent St. Croix (Virgin Is., Antilles) specimen as the epitype to support it with molecular sequence data.     

New tools for the investigations of Neuro-AIDS at a molecular level: The potential role of data-mining

Cognitive impairment represents the most significant and devastating neurological complication associated with HIV infection. Despite recent advances in our knowledge of the clinical features, pathogenesis, and molecular aspects of HIV-related dementia, current diagnostic strategies are associated with significant limitations. It has been suggested that the use of some biomarkers may assist researchers and clinicians in predicting the onset of the disease process and in evaluating the effects of new therapies. However, the large number of chemicals and metabolic pathways involved in the pathogenesis of neurodegeneration, warrants the development of novel approaches to integrate this huge amount of data. The contribution of theoretical disciplines, such as bioinformatics and data-mining, may be useful for testing new hypotheses in diagnosis and patient-centered treatment interventions.     

Transglutaminases: key regulators of cancer metastasis

The ability to metastasize represents the most important characteristic of malignant tumors. The biological details of the metastatic process remain somewhat unknown, due to difficulties in studying tumor cell behaviour with high spatial and temporal resolution in vivo. Several lines of evidence involve transglutaminases (TGs) in the key stages of tumor progression cascade, even though the molecular mechanisms remain controversial. TG expression and activity display a different role in the primary tumor or in metastatic cells. In fact, TG expression is low in the primary tumor mass, but augmented when cells acquire the metastatic phenotype. Nevertheless, in other cases, the use of inducers of TG transamidating activity seems to contrast tumor cell plasticity, migration and invasion. In the following review, the function of TGs in cancer cell migration into the extracellular matrix, adhesion to the capillary endothelium and its basement membrane, invasion and angiogenesis is discussed.     

Additive effects of beta-alanine and sodium bicarbonate on upper-body intermittent performance

We examined the isolated and combined effects of beta-alanine (BA) and sodium bicarbonate (SB) on high-intensity intermittent upper-body performance in judo and jiu-jitsu competitors. 37 athletes were assigned to one of four groups: (1) placebo (PL)+PL; (2) BA+PL; (3) PL+SB or (4) BA+SB. BA or dextrose (placebo) (6.4 g day^?1) was ingested for 4 weeks and 500 mg kg^?1 BM of SB or calcium carbonate (placebo) was ingested for 7 days during the 4th week. Before and after 4 weeks of supplementation, the athletes completed four 30-s upper-body Wingate tests, separated by 3 min. Blood lactate was determined at rest, immediately after and 5 min after the 4th exercise bout, with perceived exertion reported immediately after the 4th bout. BA and SB alone increased the total work done in +7 and 8 %, respectively. The co-ingestion resulted in an additive effect (+14 %, p < 0.05 vs. BA and SB alone). BA alone significantly improved mean power in the 2nd and 3rd bouts and tended to improve the 4th bout. SB alone significantly improved mean power in the 4th bout and tended to improve in the 2nd and 3rd bouts. BA+SB enhanced mean power in all four bouts. PL+PL did not elicit any alteration on mean and peak power. Post-exercise blood lactate increased with all treatments except with PL+PL. Only BA+SB resulted in lower ratings of perceived exertion (p = 0.05). Chronic BA and SB supplementation alone equally enhanced high-intensity intermittent upper-body performance in well-trained athletes. Combined BA and SB promoted a clear additive ergogenic effect.     

Carnosine: from exercise performance to health

Carnosine was first discovered in skeletal muscle, where its concentration is higher than in any other tissue. This, along with an understanding of its role as an intracellular pH buffer has made it a dipeptide of interest for the athletic population with its potential to increase high-intensity exercise performance and capacity. The ability to increase muscle carnosine levels via β-alanine supplementation has spawned a new area of research into its use as an ergogenic aid. The current evidence base relating to the use of β-alanine as an ergogenic aid is reviewed here, alongside our current thoughts on the potential mechanism(s) to support any effect. There is also some emerging evidence for a potential therapeutic role for carnosine, with this potential being, at least theoretically, shown in ageing, neurological diseases, diabetes and cancer. The currently available evidence to support this potential therapeutic role is also reviewed here, as are the potential limitations of its use for these purposes, which mainly focusses on issues surrounding carnosine bioavailability.     

Aloin enhances cisplatin antineoplastic activity in B16-F10 melanoma cells by transglutaminase-induced differentiation

Aloin, a natural anthracycline from aloe plant, is a hydroxyanthraquinone derivative shown to have antitumor properties. This study demonstrated that aloin exerted inhibition of cell proliferation, adhesion and invasion abilities of B16-F10 melanoma cells under non-cytotoxic concentrations. Furthermore, aloin induced melanoma cell differentiation through the enhancement of melanogenesis and transglutaminase activity. To improve the growth-inhibiting effect of anticancer agents, we found that the combined treatment of cells with aloin and low doses of cisplatin increases the antiproliferative activity of aloin. The results suggest that aloin possesses antineoplastic and antimetastatic properties, exerted likely through the induction of melanoma cell differentiation.     

The distribution of the thermally tolerant symbiont lineage (Symbiodinium clade D) in corals from Hawaii: correlations with host and the history of ocean thermal stress

Spatially intimate symbioses, such as those between scleractinian corals and unicellular algae belonging to the genus Symbiodinium, can potentially adapt to changes in the environment by altering the taxonomic composition of their endosymbiont communities. We quantified the spatial relationship between the cumulative frequency of thermal stress anomalies (TSAs) and the taxonomic composition of Symbiodinium in the corals Montipora capitata, Porites lobata, and Porites compressa across the Hawaiian archipelago. Specifically, we investigated whether thermally tolerant clade D Symbiodinium was in greater abundance in corals from sites with high frequencies of TSAs. We recovered 2305 Symbiodinium ITS2 sequences from 242 coral colonies in lagoonal reef habitats at Pearl and Hermes Atoll, French Frigate Shoals, and Kaneohe Bay, Oahu in 2007. Sequences were grouped into 26 operational taxonomic units (OTUs) with 12 OTUs associated with Montipora and 21 with Porites. Both coral genera associated with Symbiodinium in clade C, and these co‐occurred with clade D in M. capitata and clade G in P. lobata. The latter represents the first report of clade G Symbiodinium in P. lobata. In M. capitata (but not Porites spp.), there was a significant correlation between the presence of Symbiodinium in clade D and a thermal history characterized by high cumulative frequency of TSAs. The endogenous community composition of Symbiodinium and an association with clade D symbionts after long‐term thermal disturbance appear strongly dependent on the taxa of the coral host.     

Iron Regulatory Proteins Control a Mucosal Block to Intestinal Iron Absorption

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Highlights? Disruption of intestinal IRP function constrains iron absorption in adult mice ? IRPs must limit mucosal ferritin for efficient iron absorption ? IRPs control ferroportin directly and DMT1 directly or through HIF2α ? IRPs define a set point for hepcidin-mediated regulation of iron absorption