Micropropagation of Rollinia mucosa (JACQ.) baill

Summary A protocol for in vitro propagation of Rollinia mucosa, an important medicinal plant, was developed. The presence of 500 mg l⁻¹ polyvinylpyrrolidone (PVP) during explant excision was important to avoid browning. Axillary buds, adventitious buds, and shoot cluster proliferation were achieved from epicotyl and hypocotyl explants from nursery-grown seedlings. The highest direct organogenesis percentage from hypocotyl explants was obtained upon culture of explants on Murashige and Skoog medium supplemented with 2.2 μM benzyladenine (BA) plus 2.32 μM kinetin. Epicotyl explants display highest regeneration frequency on a medium containing 8.8 μM BA and 0.54 μM naphthaleneacetic acid. Gibberellic acid was necessary for shoot elongation. Root induction was observed when shoots were pretreated with activated charcoal for 7 d in the dark before culture on Woody Plant Medium supplemented with 49.21 μM indolebutyric acid for 10 d. Root development was observed when 20 g l⁻¹ sucrose was used. Rooted plantlets were acclimatized and grown in the greenhouse.     

The Expanded mtDNA Phylogeny of the Franco-Cantabrian Region Upholds the Pre-Neolithic Genetic Substrate of Basques

The European genetic landscape has been shaped by several human migrations occurred since Paleolithic times. The accumulation of archaeological records and the concordance of different lines of genetic evidence during the last two decades have triggered an interesting debate concerning the role of ancient settlers from the Franco-Cantabrian region in the postglacial resettlement of Europe. Among the Franco-Cantabrian populations, Basques are regarded as one of the oldest and more intriguing human groups of Europe. Recent data on complete mitochondrial DNA genomes focused on macrohaplogroup R0 revealed that Basques harbor some autochthonous lineages, suggesting a genetic continuity since pre-Neolithic times. However, excluding haplogroup H, the most representative lineage of macrohaplogroup R0, the majority of maternal lineages of this area remains virtually unexplored, so that further refinement of the mtDNA phylogeny based on analyses at the highest level of resolution is crucial for a better understanding of the European prehistory. We thus explored the maternal ancestry of 548 autochthonous individuals from various Franco-Cantabrian populations and sequenced 76 mitogenomes of the most representative lineages. Interestingly, we identified three mtDNA haplogroups, U5b1f, J1c5c1 and V22, that proved to be representative of Franco-Cantabria, notably of the Basque population. The seclusion and diversity of these female genetic lineages support a local origin in the Franco-Cantabrian area during the Mesolithic of southwestern Europe, ∼10,000 years before present (YBP), with signals of expansions at ∼3,500 YBP. These findings provide robust evidence of a partial genetic continuity between contemporary autochthonous populations from the Franco-Cantabrian region, specifically the Basques, and Paleolithic/Mesolithic hunter-gatherer groups. Furthermore, our results raise the current proportion (≈15%) of the Franco-Cantabrian maternal gene pool with a putative pre-Neolithic origin to ≈35%, further supporting the notion of a predominant Paleolithic genetic substrate in extant European populations.     

Hydrolysis of fish oil by hyperactivated rhizomucor miehei lipase immobilized by multipoint anion exchange

Rhizomucor miehei lipase (RML) is greatly hyperactivated (around 20‐ to 25‐fold toward small substrates) in the presence of sucrose laurate. Hyperactivation appears to be an intramolecular process because it is very similar for soluble enzymes and covalently immobilized derivatives. The hyperactivated enzyme was immobilized (in the presence of sucrose laurate) on cyanogen bromide‐activated Sepharose (very mild covalent immobilization through the amino terminal residue), on glyoxyl Sepharose (intense multipoint covalent immobilization through the region with the highest amount of Lys residues), and on different anion exchangers (by multipoint anionic exchange through the region with the highest density of negative charges). Covalent immobilization does not promote the fixation of the hyperactivated enzyme, but immobilization on Sepharose Q retains the hyperactivated enzyme even in the absence of a detergent. The hydrolysis of fish oils by these hyperactivated enzyme derivatives was sevenfold faster than by covalently immobilized derivatives and three and a half times faster than by the enzyme hyperactivated on octyl‐Sepharose. The open structure of the hyperactivated lipase is fairly exposed to the medium, and no steric hindrance should interfere with the hydrolysis of large substrates. These new hyperactivated derivatives seem to be more suitable for hydrolysis of oils by RML immobilized inside porous supports. In addition, the hyperactivated derivatives are fairly stable against heat and organic cosolvents. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011     

N-2-acetylaminofluorene modification of poly(dG-m5dC)·poly(dG-m5dC) induces the Z-DNA conformation

Poly(dG-m⁵dC)·poly(dG-m⁵dC) was modified by treatment with N-acetoxy-N-2-acetylaminofluorene (N-Aco-AAF) and its conformation examined by circular dichroism (CD) and susceptibility to S₁ nuclease digestion. A sample with a modification level of 10% shows a CD spectrum characteristic of the Z form and is resistant to digestion by S₁ nuclease. The relative reactivity of several polymers with N-Aco-AAF was shown to follow the order of ease of formation of Z DNA: poly(dG-m⁵dC)·poly(dG-m⁵dC) > poly(dG-dC)·poly(dG-dC) > poly(dG)·poly(dC). This suggests that AAF reacts more readily with Z DNA than B DNA.     

Application of the Red List Index as an indicator of habitat change

For the first time ever, the International Union for Conservation of Nature Red List Index for habitat types was calculated for an entire country, Finland. The RLIs were based on species threat assessments from 2000 and 2010 and included habitat definitions for all 10,131 species of 12 organism groups. The RLIs were bootstrapped to track statistically significant changes. The RLI changes of species grouped by habitats were negative for all habitat types except for forests and rural biotopes which showed a stable trend. Trends of beetles and true bugs were positive in rural and forest habitats. Other 16 observed trends of species group and habitat combinations were negative. Several trends observed were in accordance with studies focusing on particular taxa and habitats, and drivers for their change. This study demonstrates the usefulness of the RLI as a tool for observing habitat change based on species threat assessment data.     

Targeting Homologous Recombination in Notch-Driven C. elegans Stem Cell and Human Tumors

Mammalian NOTCH1-4 receptors are all associated with human malignancy, although exact roles remain enigmatic. Here we employ glp-1(ar202), a temperature-sensitive gain-of-function C. elegans NOTCH mutant, to delineate NOTCH-driven tumor responses to radiotherapy. At ≤20°C, glp-1(ar202) is wild-type, whereas at 25°C it forms a germline stem cell⁄progenitor cell tumor reminiscent of human cancer. We identify a NOTCH tumor phenotype in which all tumor cells traffic rapidly to G2⁄M post-irradiation, attempt to repair DNA strand breaks exclusively via homology-driven repair, and when this fails die by mitotic death. Homology-driven repair inactivation is dramatically radiosensitizing. We show that these concepts translate directly to human cancer models.     

Stability of the Transthyretin Molecule as a Key Factor in the Interaction with A-Beta Peptide - Relevance in Alzheimer's Disease

Transthyretin (TTR) protects against A-Beta toxicity by binding the peptide thus inhibiting its aggregation. Previous work showed different TTR mutations interact differently with A-Beta, with increasing affinities correlating with decreasing amyloidogenecity of the TTR mutant; this did not impact on the levels of inhibition of A-Beta aggregation, as assessed by transmission electron microscopy. Our work aimed at probing differences in binding to A-Beta by WT, T119M and L55P TTR using quantitative assays, and at identifying factors affecting this interaction. We addressed the impact of such factors in TTR ability to degrade A-Beta. Using a dot blot approach with the anti-oligomeric antibody A11, we showed that A-Beta formed oligomers transiently, indicating aggregation and fibril formation, whereas in the presence of WT and T119M TTR the oligomers persisted longer, indicative that these variants avoided further aggregation into fibrils. In contrast, L55PTTR was not able to inhibit oligomerization or to prevent evolution to aggregates and fibrils. Furthermore, apoptosis assessment showed WT and T119M TTR were able to protect against A-Beta toxicity. Because the amyloidogenic potential of TTR is inversely correlated with its stability, the use of drugs able to stabilize TTR tetrameric fold could result in increased TTR/A-Beta binding. Here we showed that iododiflunisal, 3-dinitrophenol, resveratrol, [2-(3,5-dichlorophenyl)amino] (DCPA) and [4-(3,5-difluorophenyl)] (DFPB) were able to increase TTR binding to A-Beta; however only DCPA and DFPB improved TTR proteolytic activity. Thyroxine, a TTR ligand, did not influence TTR/A-Beta interaction and A-Beta degradation by TTR, whereas RBP, another TTR ligand, not only obstructed the interaction but also inhibited TTR proteolytic activity. Our results showed differences between WT and T119M TTR, and L55PTTR mutant regarding their interaction with A-Beta and prompt the stability of TTR as a key factor in this interaction, which may be relevant in AD pathogenesis and for the design of therapeutic TTR-based therapies.     

α-MELANOCYTE-STIMULATING HORMONE: A POSSIBLE NEURONAL MARKER OF THE AGEING BRAIN

Abstract— The amount of α-melanocyte-stimulating hormone (α-MSH) in the entire hypothalamus as well as the amount of α-MSH in free granule and synaptosome fractions of hypothalamic homogenates was investigated throughout the lifespan of female rats (1-24 months). A 900 g supernatant fluid was prepared from hypothalami following homogenization in an iso-osmotic sucrose solution, and free granules and synaptosomes containing α-MSH were fractionated by means of continuous sucrose density gradient centrifugation. α-MSH was quantified by radioimmunoassay. The total amount of α-MSH in the hypothalamus, as well as the amount in free granules and synaptosomes prepared from hypothalami increased progressively from the 1st to the 5th month of life, and this increase was more pronounced in the free granules than in the synaptosomes. On the other hand, the amount of α-MSH in the hypothalamus and the amount present in free granules and synaptosomes prepared from 5-24-month-old animals decreased with age, and this decrease appeared to proceed at similar rates in both subcellular compartments. Based on these results, it is suggested that ageing of α-MSH neurons in the hypothalamus is accompanied by a degeneration of the axons and/or an alteration in the biosynthetic and degradative activities of the neuron.