The integration of mutant loci affecting maize endosperm development in a dense genetic map using an AFLP-based procedure

In this paper, 10 mutations conditioning the appearance of defective, miniature or collapsed endosperm, but with normal sporophyte development, were considered. Homozygous mutant kernels have reduced grain weight, kernel size, density and, in some of these, higher than normal seed protein content. The mutant loci were integrated into a high-resolution genetic map in order to associate them to specific genes. We have placed 1167 AFLP markers on a consensus map using IBM2 as a backbone and reaching an average of 1 marker every 1.9 cM. We have identified AFLP markers linked to all individual mutant alleles. BSA was adopted to screen the largest possible number of primer combinations on homozygous F₃ mutant and wild type plants. The ten mutant loci are linked to the closest AFLP or SSR markers with distances ranging from 0 to 17.9 cM. The genes we have defined by the existence of mendelian mutants can now be considered good candidates for testing the association to QT loci. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Investigating pollination strategies in disturbed habitats: the case of the narrow-endemic toadflax Linaria tonzigii (Plantaginaceae) on mountain screes

Plant Ecology - Plant mating systems may reflect an adaptation to a habitat type, with self-pollination being potentially common in unstable and disturbed conditions. We investigated the...     

Synthesis and characterization of tetra-end linked oligonucleotides capable of forming monomolecular G-quadruplexes

The chemical synthesis of two new G-rich Tetra-End-Linked-oligodeoxyribonucleotides (TEL-ODNs) as well as (1)H-NMR and CD spectra of the corresponding monomolecular quadruplexes (IVa and IVb) has been reported. The new TEL-ODNs, characterized by the presence of short branches in the linker moiety, could be very useful for the achievement of monomolecular quadruplexes with predetermined strand orientation.     

Astacin-like metalloproteases are a gene family of toxins present in the venom of different species of the brown spider (genus Loxosceles)

Brown spiders have a worldwide distribution, and their venom has a complex composition containing many different molecules. Herein, we report the existence of a family of astacin-like metalloprotease toxins in Loxosceles intermedia venom, as well as in the venom of different species of Loxosceles. Using a cDNA library from the L. intermedia venom gland, we cloned two novel cDNAs encoding astacin-like metalloprotease toxins, LALP2 and LALP3. Using an anti-serum against the previously described astacin-like toxin in L. intermedia venom (LALP1), we detected the presence of immunologically-related toxins in the venoms of L. intermedia, Loxosceles laeta, and Loxosceles gaucho. Zymographic experiments showed gelatinolytic activity of crude venoms of L. intermedia, L. laeta, and L. gaucho (which could be inhibited by the divalent metal chelator 1,10-phenanthroline) at electrophoretic mobilities identical to those reported for immunological cross-reactivity. Moreover, mRNAs extracted from L. laeta and L. gaucho venom glands were screened for astacin-like metalloproteases, and cDNAs obtained using LALP1-specific primers were sequenced, and their deduced amino acid sequences confirmed they were members of the astacin family with the family signatures (HEXXHXXGXXHE and MXY), LALP4 and LALP5, respectively. Sequence comparison of deduced amino acid sequences revealed that LALP2, LALP3, LALP4, and LALP5 are related to the astacin family. This study identified the existence of gene family of astacin-like toxins in the venoms of brown spiders and raises the possibility that these molecules are involved in the deleterious effects triggered by the venom.     

Cytotoxin‐Associated Gene‐A – Positive Helicobacter pylori Strains Infection Increases the Risk of Recurrent Atherosclerotic Stroke

Background: CagA‐positive Helicobacter pylori infection has been found to be associated with a first‐ever atherosclerotic stroke. The aim of this study was to investigate whether these strains represent an independent risk factor for recurrent atherosclerotic stroke. Materials and Methods: We performed a longitudinal study of patients with a first‐ever large vessels stroke and resulted positive at H. pylori serology. Patients had clinical examination 1 month after the acute event, and were subsequently visited or contacted by telephone up to 3 years at 6‐month intervals. Sera obtained at the time of enrollment were frozen and analyzed for the presence of anti‐CagA antibodies at the end of the study. The primary outcome event was any fatal or nonfatal stroke after the index stroke. Results: One hundred seventy H. pylori‐positive patients were included (n = 68 CagA positive and n = 102 CagA negative). No significant difference regarding age and other stroke risk factors was detected. According to Kaplan‐Meier survival analysis, CagA‐positive patients showed a significantly higher risk for stroke recurrence than CagA‐negative ones (45.6% vs 17.6%; p < .001). Difference in the rate of recurrent stroke between the two groups persisted after Cox regression analysis taking into account possible confounding factors (hazard ratio = 3.5; 95% CI = 1.9–6.4; p < .001). Conclusions: Infection with H. pylori CagA‐positive strains increases the risk of recurrent atherosclerotic stroke. Seropositivity determination should be performed in order to identify high‐risk patients requiring a strict clinical surveillance, and the possible beneficial effect of eradication therapy should be evaluated.