Abstract Various chemical, natural, or synthetic in origin, crosslinking methods have been proposed over the years to stabilise collagen fibers. However, an optimal method has yet to be identified. Herein, we ventured to assess the potential of 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate, as opposed to glutaraldehyde (GTA), genipin and carbodiimide, on the structural, physical and biological properties of collagen fibers. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate induced an intermedium surface smoothness, denaturation temperature and swelling. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate fibers had significantly higher stress at break values than the carbodiimide fibers, but significantly lower than the GTA and genipin fibers. With respect to strain at break, no significant difference was observed among the crosslinking treatments. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate fibers exhibited significantly higher cell metabolic activity and DNA concentration that all other crosslinking treatments, promoted consistently cellular elongation along the longitudinal fiber axis and by day 7 they were completely covered by cells. Collectively, this work clearly demonstrates the potential of 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate as collagen crosslinker. ? 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 914?922, 2016.

Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is considered a promising source for improving stress resistances in domesticated wheat. Here we explored the potential of selected quantitative trait loci (QTLs) from wild emmer wheat, introgressed via marker-assisted selection, to enhance drought resistance in elite durum (T. turgidum ssp. durum) and bread (T. aestivum) wheat cultivars. The resultant near-isogenic lines (BC₃F₃ and BC₃F₄) were genotyped using SNP array to confirm the introgressed genomic regions and evaluated in two consecutive years under well-watered (690–710 mm) and water-limited (290–320 mm) conditions. Three of the introgressed QTLs were successfully validated, two in the background of durum wheat cv. Uzan (on chromosomes 1BL and 2BS), and one in the background of bread wheat cvs. Bar Nir and Zahir (chromosome 7AS). In most cases, the QTL x environment interaction was validated in terms of improved grain yield and biomass—specifically under drought (7AS QTL in cv. Bar Nir background), under both treatments (2BS QTL), and a greater stability across treatments (1BL QTL). The results provide a first demonstration that introgression of wild emmer QTL alleles can enhance productivity and yield stability across environments in domesticated wheat, thereby enriching the modern gene pool with essential diversity for the improvement of drought resistance.

Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is considered a promising source for improving drought resistance in domesticated wheat. Nevertheless, wild germplasm has not been widely used in wheat breeding for abiotic stress resilience. In the current study, a near isogenic line NIL-7A-B-2, introgressed with a drought-related QTL from wild emmer wheat on chromosome 7A, and its recurrent parent, bread wheat cv. BarNir, were investigated under four environments across 2 years—water-limited and well-watered conditions in a rain-protected screen-house (Year 1) and two commercial open field plots under ample precipitation (Year 2). NIL-7A-B-2 exhibited an advantage over BarNir in grain yield and biomass production under most environments. Further physiological analyses suggested that enhanced photosynthetic capacity and photochemistry combined with higher flag leaf area are among the factors underlying the improved productivity of NIL-7A-B-2. These were coupled with improved sink capacity in NIL-7A-B-2, manifested by greater yield components than its parental line. This study provides further support for our previous findings that introgression of wild emmer QTL alleles, using marker assisted selection, can enhance grain yield and biomass production across environments in domesticated wheat, thereby enriching the modern gene pool with essential diversity for the improvement of yield and drought resistance.

Summary Viruses that infect marine photosynthetic microorganisms are major ecological and evolutionary drivers of microbial food webs, estimated to turn over more than a quarter of the total photosynthetically fixed carbon. Viral infection of the bloom-forming microalga Emiliania huxleyi induces the rapid remodeling of host primary metabolism, targeted towards fatty acid metabolism. We applied a liquid chromatography-mass spectrometry (LC-MS)-based lipidomics approach combined with imaging flow cytometry and gene expression profiling to explore the impact of viral-induced metabolic reprogramming on lipid composition. Lytic viral infection led to remodeling of the cellular lipidome, by predominantly inducing the biosynthesis of highly saturated triacylglycerols (TAGs), coupled with a significant accumulation of neutral lipids within lipid droplets. Furthermore, TAGs were found to be a major component (77%) of the lipidome of isolated virions. Interestingly, viral-induced TAGs were significantly more saturated than TAGs produced under nitrogen starvation. This study highlights TAGs as major products of the viral-induced metabolic reprogramming during the host?virus interaction and indicates a selective mode of membrane recruitment during viral assembly, possibly by budding of the virus from specialized subcellular compartments. These findings provide novel insights into the role of viruses infecting microalgae in regulating metabolism and energy transfer in the marine environment and suggest their possible biotechnological application in biofuel production.

The cosmopolitan coccolithophore Emiliania huxleyi is a unicellular eukaryotic alga responsible for vast blooms in the ocean. These blooms have immense impact on large biogeochemical cycles and are terminated by a specific large double-stranded DNA E. huxleyi virus (EhV, Phycodnaviridae). EhV infection is accompanied by induction of hallmarks of programmed cell death and production of reactive oxygen species (ROS). Here we characterized alterations in ROS metabolism and explored its role during infection. Transcriptomic analysis of ROS-related genes predicted an increase in glutathione (GSH) and H2O2 production during infection. In accordance, using biochemical assays and specific fluorescent probes we demonstrated the overproduction of GSH during lytic infection. We also showed that H2O2 production, rather than superoxide, is the predominant ROS during the onset of the lytic phase of infection. Using flow cytometry, confocal microscopy and multispectral imaging flow cytometry, we showed that the profound co-production of H2O2 and GSH occurred in the same subpopulation of cells but at different subcellular localization. Positively stained cells for GSH and H2O2 were highly infected compared with negatively stained cells. Inhibition of ROS production by application of a peroxidase inhibitor or an H2O2 scavenger inhibited host cell death and reduced viral production. We conclude that viral infection induced remodeling of the host antioxidant network that is essential for a successful viral replication cycle. This study provides insight into viral replication strategy and suggests the use of specific cellular markers to identify and quantify the extent of active viral infection during E. huxleyi blooms in the ocean.

Abstract Oxidative stress is generated in plants because of inequalities in the rate of reactive oxygen species (ROS) generation and scavenging. The subcellular redox state under various stress conditions was assessed using the redox reporter roGFP2 targeted to chloroplastic, mitochondrial, peroxisomal and cytosolic compartments. In parallel, the vitality of the plant was measured by ion leakage. Our results revealed that during certain physiological stress conditions the changes in roGFP2 oxidation are comparable to application of high concentrations of exogenous H2O2. Under each stress, particular organelles were affected. Conditions of extended dark stress, or application of elicitor, impacted chiefly on the status of peroxisomal redox state. In contrast, conditions of drought or high light altered the status of mitochondrial or chloroplast redox state, respectively. Amalgamation of the results from diverse environmental stresses shows cases of organelle autonomy as well as multi-organelle oxidative change. Importantly, organelle-specific oxidation under several stresses proceeded cell death as measured by ion leakage, suggesting early roGFP oxidation as predictive of cell death. The measurement of redox state in multiple compartments enables one to look at redox state connectivity between organelles in relation to oxidative stress as well as assign a redox fingerprint to various types of stress conditions.

Marine viruses are considered to be major ecological, evolutionary, and biogeochemical drivers of the marine environment, responsible for nutrient recycling and determining species composition. Viruses can re-shape their host's metabolic network during infection, generating the virocell–a unique metabolic state that supports their specific requirement. Here we discuss the concept of ‘virocell metabolism’ and its formation by rewiring of host-encoded metabolic networks, or by introducing virus-encoded auxiliary metabolic genes which provide the virocell with novel metabolic capabilities. The ecological role of marine viruses is commonly assessed by their relative abundance and phylogenetic diversity, lacking the ability to assess the dynamics of active viral infection. The new ability to define a unique metabolic state of the virocell will expand the current virion-centric approaches in order to quantify the impact of marine viruses on microbial food webs.