Tandem quadruplication of HMA4 in the zinc (Zn) and cadmium (Cd) hyperaccumulator noccaea caerulescens

Zinc (Zn) and cadmium (Cd) hyperaccumulation may have evolved twice in the Brassicaceae, in Arabidopsis halleri and in the Noccaea genus. Tandem gene duplication and deregulated expression of the Zn transporter, HMA4, has previously been linked to Zn/Cd hyperaccumulation in A. halleri. Here, we tested the hypothesis that tandem duplication and deregulation of HMA4 expression also occurs in Noccaea. A Noccaea caerulescens genomic library was generated, containing 36,864 fosmid pCC1FOSTM clones with insert sizes ~20–40 kbp, and screened with a PCR-generated HMA4 genomic probe. Gene copy number within the genome was estimated through DNA fingerprinting and pooled fosmid pyrosequencing. Gene copy numbers within individual clones was determined by PCR analyses with novel locus specific primers. Entire fosmids were then sequenced individually and reads equivalent to 20-fold coverage were assembled to generate complete whole contigs. Four tandem HMA4 repeats were identified in a contiguous sequence of 101,480 bp based on sequence overlap identities. These were flanked by regions syntenous with up and downstream regions of AtHMA4 in Arabidopsis thaliana. Promoter-reporter b-glucuronidase (GUS) fusion analysis of a NcHMA4 in A. thaliana revealed deregulated expression in roots and shoots, analogous to AhHMA4 promoters, but distinct from AtHMA4 expression which localised to the root vascular tissue. This remarkable consistency in tandem duplication and deregulated expression of metal transport genes between N. caerulescens and A. halleri, which last shared a common ancestor >40 mya, provides intriguing evidence that parallel evolutionary pathways may underlie Zn/Cd hyperaccumulation in Brassicaceae

Context-Dependent Dual Role of SKI8 Homologs in mRNA Synthesis and Turnover

Eukaryotic mRNA transcription and turnover is controlled by an enzymatic machinery that includes RNA polymerase II and the 3′ to 5′ exosome. The activity of these protein complexes is modulated by additional factors, such as the nuclear RNA polymerase II-associated factor 1 (Paf1c) and the cytoplasmic Superkiller (SKI) complex, respectively. Their components are conserved across uni- as well as multi-cellular organisms, including yeast, Arabidopsis, and humans. Among them, SKI8 displays multiple facets on top of its cytoplasmic role in the SKI complex. For instance, nuclear yeast ScSKI8 has an additional function in meiotic recombination, whereas nuclear human hSKI8 (unlike ScSKI8) associates with Paf1c. The Arabidopsis SKI8 homolog VERNALIZATION INDEPENDENT 3 (VIP3) has been found in Paf1c as well; however, whether it also has a role in the SKI complex remains obscure so far. We found that transgenic VIP3-GFP, which complements a novel vip3 mutant allele, localizes to both nucleus and cytoplasm. Consistently, biochemical analyses suggest that VIP3–GFP associates with the SKI complex. A role of VIP3 in the turnover of nuclear encoded mRNAs is supported by random-primed RNA sequencing of wild-type and vip3 seedlings, which indicates mRNA stabilization in vip3. Another SKI subunit homolog mutant, ski2, displays a dwarf phenotype similar to vip3. However, unlike vip3, it displays neither early flowering nor flower development phenotypes, suggesting that the latter reflect VIP3's role in Paf1c. Surprisingly then, transgenic ScSKI8 rescued all aspects of the vip3 phenotype, suggesting that the dual role of SKI8 depends on species-specific cellular context

Gli aneurismi dell\u2019aorta pararenale : definizione, classificazione, indicazione al trattamento chirurgico

The formidable impact derived by the endovascular correc tion (Fvar) of abdominal aorta aneurysms (AAA), has risen its classification aspects. The topographieal criteria has assumed importance in decisional diagnostic therapeutic strategy, especially in cases of so c,tiled pararenal aneurysms (PRAA). Delmition: PRAA defines aneurysm being involved unde- renal juxtarenal aorta (JRA), or more rarely, suprarenal aorta with normal aortic diameter at level of celiac (/RA), or more rarely, suprarenal aorta with normal aortic dm meter at level of celiac trunk. (.lassification: Phe morphologic topographic aspect is considered in function of selection or eligibility of patients to h.var or standard open surgery, in the need of a suprarenal clamping for the tailoring of proximal anastomosys or anchorage of endoprotesis. Various specific classifications for tin \u25a0se aneurysms have been proposed {Schumacher, 199"'; Wolf 2000; Ayari, 2001) that considers: Aneurysm collar: short/long/tortuous Relations with renal arteries .i Relations with the left renal vein Directions for surgical treatment: Phe choice between the technical solution to prefer either open or cndovascular surgery will have to consider a series of additional variables to the standard direction common to every AAA based on dimensions and morphology. Priority will have n> be given to evaluating, using shared morphologic-topographical das sification criteria, real incidence of PRAA-JRA (A\ub0o-20% in literature review); greater post opening mortality (l,.i"o- 15,j\ub0-o); dimensions (AAA with diameter a 5,') cm in ope rating risk assessment of single patient, in clinic,d evolution and increase in the tune iff the lesion); m common occu ranee in AAA of steno-obstructive lesions of renal arteries and involvement of same ones in the aneurysm collar in need of reconstruction and suprarenal aortic clamping. Copyrigh

Policy-based Restoration in IP/Optical Transport Networks

Restoration in transport networks is typically facilitated using reactive techniques at different layers, namely optical and IP restoration [1]. Optical restoration involves re-routing an existing optical connection (i.e., a lightpath) around a failure (e.g. link, amplifier, switch and transponder failures) in the optical layer. This strategy is efficient in terms of resource utilization, as backup resources are reserved dynamically after the failure and therefore are not blocked during normal operation. However, equipment reconfiguration and power equalization processes in the optical domain are relatively slow (order of seconds), and are thus not suitable for time critical services