Biosynthesis of Vitamin C by Yeast Leads to Increased Stress Resistance

during respiration, or indirectly-caused by other stressing factors. Vitamin C or L-ascorbic acid acts as a scavenger of ROS, thereby potentially protecting cells from harmful oxidative products. While most eukaryotes synthesize ascorbic acid, yeast cells produce erythro-ascorbic acid instead. The actual importance of this antioxidant substance for the yeast is still a subject of scientific debate. is increased, but also the tolerance to low pH and weak organic acids at low pH is increased. cells endogenously producing vitamin C as a cellular model to study the genesis/protection of ROS as well as genotoxicity

Self-Strangulation Through A Sphygmomanometer: An Uncommon Suicide

Suicide by asphyxia is quite a common event in forensic practice and may be implemented in different ways. The authors report a unique case of a 16-year-old youth who committed suicide by means of a standard mercury sphygmomanometer. This manner of suicide has never been described in the literature reviewed. A complete forensic investigation led to the conclusion that the cause of death was mechanical asphyxia, ascribed to self-strangulation by means of an atypical item. The victim suffered from attention-deficit/hyperactivity disorder (ADHD) syndrome and was assisted by support teachers. He had a solitary and depressive personality. The exceptional nature of this case suggests that sphygmomanometers may be regarded as possible means of self-strangulation. The case also highlights the importance of managing patients with psychiatric or cognitive disorders; indeed, particular caution is required to keep them away from objects that, although apparently harmless, can become lethal

High zinc concentrations reduce rooting capacity and alter metallothionein gene expression in white poplar (Populus alba L. cv. Villafranca)

Poplar is a good candidate for phytoremediation purposes because of its rapid growth, extensive root system, and ease of propagation and transformation; however its tolerance to heavy metals has not been fully investigated yet. In the present work, an in vitro model system with shoot cultures was used to investigate the tolerance to high concentrations of zinc (Zn) of a commercial clone (Villafranca) of Populus alba. Based on chlorophyll content (leaf chlorosis) and the rate of adventitious root formation from shoot cuttings as parameters of damage, 0.5-4 mM zinc concentrations were all toxic albeit to different extents. Northern blot and reverse transcriptase (RT)-PCR analyses were used to examine the expression profiles of types 1, 2 and 3 PaMT genes in stems, leaves and roots of plants exposed to Zn treatments. In leaves, MT1 and MT3 mRNA levels were enhanced by Zn, while MT2 transcripts were not affected. The PaMT expression profiles were differentially affected by Zn in an organ-specific manner, and the relationship with Zn concentration and exposure time was rarely linear. The developmental and molecular data reveal that the in vitro model is a sensitive and reliable system to study heavy metal stress responses. © 2006 Elsevier Ltd. All rights reserved

Genetic relationships and clonal identity in a collection of commercially relevant poplar cultivars assessed by AFLP and SSR

A collection of 66 poplar commercial clones widely cultivated in Italy, China and in other countries of southern Europe and belonging to various poplar species and hybrids, have been fingerprinted using both amplified fragment length polymorphism(AFLP) and simple sequence repeats (SSR) techniques. Three AFLP primer combinations and six SSRs unambiguously genotyped the analysed poplar collection, with the exception of three groups of six, four and two individuals, which turned out to be indistinguishable even if they met the standards currently applied for distinctness, uniformity and stability (DUS) testing when registered. High levels of variation were detected with both molecular techniques; a total of 201 AFLP bands were amplified of which 96% turned out to be polymorphic and up to 15 SSR alleles were identified at a single locus, with a mean of 9.3 alleles per locus in the case of Populus 7 canadensis. The probability of matching fortuitously any two genotypes at all the SSR loci in the case of P. 7 canadensis was less then 7.5 710 129. The AFLP-derived dendrogram and principal coordinate analysis (PCOORDA) clustered the clones with respect to their taxonomic classification, and allowed their genetic interrelationships to be established. Correct identification of poplar varieties is essential for ensuring the effective correspondence between the real and the declared identity of a clone, to avoid commercial frauds, and to establish breeding programmes. Molecular markers may play a major role to satisfy all these needs

The Origin of clonal diversity and structure of <i>Populus alba</i> in Sardinia: evidence from nuclear and plastid microsatellite markers

Background and Aims. Populus alba is a thermophilic forest tree present in the Mediterranean basin. Its habitat is highly fragmented and its distribution range has been subject to long-term human interference, resulting in debate surrounding whether certain populations are native or exotic in origin. In particular, populations from the islands of Corsica and Sardinia are of uncertain origin. While populations of P. alba mainly reproduce sexually, clonal reproduction is also common. The aims of this study were to locate and molecularly characterize the poorly studied island populations of P. alba and compare these with samples from various spatial scales, in order to provide information on the genetic structure and phylogeography of this species. This information will provide evidence on whether the species is native to Sardinia, which is important for the development of conservation strategies. Methods. DNA extracts were obtained from the following P. alba trees: 159 from Sardinia, 47 from Ticino regional park (northern Italy), 15 acquired from an Italian Germoplasm Bank (IRC; Italian Reference Collection) and 28 from the Mediterranean basin (MB). Genetic polymorphisms were revealed at nuclear and chloroplast DNA (cpDNA) microsatellite loci, both at the island scale (Sardinia) and at broader scales, for comparative assessment of the genetic and genotypic diversity and phylogeography. Key Results. Based on nuclear microsatellite loci, Sardinian white poplar consists of a small number of genets (26), each of which is represented by several ramets. Despite the uniqueness of the Sardinian haplotypes and the very low value of genetic diversity at the cpDNA level (vK = 0•15), the HT (0•60) and the AR (3•61) values, estimated at the nuclear level for Sardinia, were comparable with those of the other populations and collections. Conclusions. The uniqueness of the cpDNA haplotypes, the prevalence of clonality and the restricted number of genets recorded suggest that Sardinian white poplar could be a floristic relict of the native flora of the island, which has spread through available habitats on the island mainly by means of vegetative propagation and human activities

List of yeast strains constructed and used in this study

<p>List of yeast strains constructed and used in this study</p

Growth curves of wild type and L-ascorbic acid producing yeasts under oxidative stress.

<p>Kinetics of growth of wild type and engineered strains GRF18U (left panels) and BY4742 (right panels) as inoculated in minimal glucose media without H₂O₂ (3A and 3B) or in presence of H₂O₂ 3.5 mM (3C and 3D). • GRF18U wild type; ▪ GRF18U[<i>ScALO AtLGDH AtME AtMIP</i>]; ▴ GRF18U[<i>ScALO AtLGDH AtME AtMIP RnFGT</i>]; ○ BY4742 wild type; □ BY4742[<i>ScALO AtLGDH AtME AtMIP</i>]; ▵ BY4742[<i>ScALO AtLGDH AtME AtMIP RnFGT</i>].</p

Flow cytometric analysis of wild type and vitamin C producing yeasts under oxidative stress.

<p>Panel 5A: schematic representation of the different subpopulations that can be observed in the following panels, where wild type (5B) and recombinant strains (5C and 5D) grown in minimal glucose medium added with H₂O₂ 3.0 mM were analyzed after DHR123 and PI staining (rodamine signal is reported in the abscissa and PI signal on the ordinate axes). Upper panels: GRF18U background. Lower panels: BY background. (B): wild type. (C): [<i>ScALO AtLGDH AtME AtMIP</i>] transformed cells. (D): [<i>ScALO AtLGDH AtME AtMIP RnFGT</i>] transformed cells</p