Mitogenomics of Vetigastropoda: insights into the evolution of pallial symmetry

The nucleotide sequences of the complete or nearly complete mitochondrial (mt) genomes of seven vetigastropods were determined: Angaria neglecta (Angarioidea), Phasianella solida (Phasianelloidea), Granata lyrata (Seguenzioidea), Tegula lividomaculata and Bolma rugosa (Trochoidea), Diodora graeca (Fissurelloidea) and Lepetodrilus schrolli (Lepetodriloidea). While the mt genomes of the superfamilies Angarioidea, Phasianelloidea, Seguenzioidea and Trochoidea conform generally to the ancestral gene order of Vetigastropoda and Gastropoda, those of the superfamilies Fissurelloidea and Lepetodriloidea have suffered important rearrangements. The gene order of the mtDNA of Chrysomallon squamiferum, a representative of Neomphalina, was also analysed since it has been proposed to be closely related to Vetigastropoda, and showed a distinct arrangement. The reconstructed phylogenies recovered Neomphalina as a distinct gastropod lineage that is the sister group (only with moderate bootstrap support) of a clade including Vetigastropoda and Neritimorpha + Caeno‐gastropoda while the relative position of Heterobranchia and Patellogastropoda in the gastropod tree could not be determined definitively due to their long branches. Within the monophyletic Vetigastropoda, the superfamily Fissurelloidea was recovered as the sister group of two lineages, one including Lepetodriloidea as the sister group of Seguenzioidea + Halitoidea, the other including Phasianelloidea, Angarioidea and Trochoidea without resolved relationships. The long branches of Fissurelloidea were found to introduce significant tree instability in phylogenetic reconstruction. The new phylogeny supports that the loss of the right pallial gill occurred multiple times in vetigastropod evolution as previously suggested and that Phasianelloidea, Angarioidea and Trochoidea radiated from a common asymmetric (single‐gilled) ancestor that lived in the middle Palaeozoic.     

The use of rapid dengue diagnostic tests in a routine clinical setting in a dengue-endemic area of Colombia

There is insufficient evidence of the usefulness of dengue diagnostic tests underroutine conditions. We sought to analyse how physicians are using dengue diagnosticsto inform research and development. Subjects attending 14 health institutions in anendemic area of Colombia with either a clinical diagnosis of dengue or for whom adengue test was ordered were included in the study. Patterns of test-use aredescribed herein. Factors associated with the ordering of dengue diagnostic testswere identified using contingency tables, nonparametric tests and logisticregression. A total of 778 subjects were diagnosed with dengue by the treatingphysician, of whom 386 (49.5%) were tested for dengue. Another 491 dengue tests wereordered in subjects whose primary diagnosis was not dengue. Severe dengueclassification [odds ratio (OR) 2.2; 95% confidence interval (CI) 1.1-4.5], emergencyconsultation (OR 1.9; 95% CI 1.4-2.5) and month of the year (OR 3.1; 95% CI 1.7-5.5)were independently associated with ordering of dengue tests. Dengue tests were usedboth to rule in and rule out diagnosis. The latter use is not justified by thesensitivity of current rapid dengue diagnostic tests. Ordering of dengue tests appearto depend on a combination of factors, including physician and institutionalpreferences, as well as other patient and epidemiological factors.     

New template reactions of salicylaldehyde S-methyl-isothiosemicarbazone with 2-formylpyridine promoted by Ni(II) or Cu(II) metal ions

The template reaction between salicylaldehyde S-methyl-isothiosemicarbazone and 2-formylpyridine in presence of nickel(II) or copper(II) salts yields two new coordination compounds with general formula [NiL¹]₂(1) and [CuL²]₂(2) (L¹ = the dianionic (N¹-salicylidene)(N⁴-(hydroxy(pyridin-2-yl)methyl) S-methyl-isothiosemicarbazide) ligand and L² = the doubly deprotonated (N¹-salicylidene)(N⁴-(picolinoyl) S-methyl-isothiosemicarbazide) ligand). In the complex 1, the formed L¹ ligand appears as result of an addition reaction of the precursors, while for 2 a redox mechanism is implicated in the formation of L². Despite the fact that the initial organic precursors are the same, the resulting ligands obtained in the template reaction are different. In 1, the Ni(II) metal ion adopts a square-planar geometry and the [NiL¹] units are forming dimerized chains through weak Ni···Ni interactions (3.336 and 3.632 Å). In 2, the Cu(II) metal ions adopt a square-pyramidal geometry and form dinuclear species through weak Cu···O (phenoxo) interactions. The magnetic susceptibility measurements of the complexes reveal the diamagnetic nature of 1 as expected for a square planar Ni(II) complex and a paramagnetic behavior for 2 with weak intra-dimer antiferromagnetic interaction (J/k_B = −2.1(1) K).     

Heavy metal-induced oxidative damage, defense reactions, and detoxification mechanisms in plants

Heavy metal (HMs) contamination is widespread globally due to anthropogenic, technogenic, and geogenic activities. The HMs exposure could lead to multiple toxic effects in plants by inducing reactive oxygen species (ROS), which inhibit most cellular processes at various levels of metabolism. ROS being highly unstable could play dual role (1) damaging cellular components and (2) act as an important secondary messenger for inducing plant defense system. Cells are equipped with enzymatic and non-enzymatic defense mechanisms to counteract this damage. Some are constitutive and others that are activated only when a stress-specific signal is perceived. Enzymatic scavengers of ROS include superoxide dismutase, catalase, glutathione reductase, and peroxidase, while non-enzymatic antioxidants are glutathione, ascorbic acid, α-tocopherol, flavonoids, anthocyanins, carotenoids, and organic acids. The intracellular and extracellular chelation mechanisms of HMs are associated with organic acids such as citric, malic and oxalic acid, etc. The important mechanism of detoxification includes metal complexation with glutathione, amino acids, synthesis of phytochelatins and sequestration into the vacuoles. Excessive stresses induce a cascade, MAPK (mitogen-activated protein kinase) pathway and synthesis of metal-detoxifying ligands. Metal detoxification through MAPK cascade and synthesis of metal-detoxifying ligands will be of considerable interest in the field of plant biotechnology. Further, the photoprotective roles of pigments of xanthophylls cycle under HMs stress were also discussed.     

Calcium ionophoretic activity of chemically synthesized oligomeric derivatives of prostaglandin B1

Chemically synthesized dimers, trimers and tetramers of 15-dehydroprostaglandin B1 and 16,16'-dimethyl-15-dehydroprostaglandin B1 facilitate the release of Ca2+ from isolated rat liver mitochondria. The parent monomeric prostaglandins had no significant activity. The rate of release was stimulated by exogenous K+ or Na+, suggesting an antiport exchange of monovalent cations for intra-mitochondrial Ca2+. The activity depended upon the presence of ruthenium red, which prevented recycling of Ca2+; comparison of the activity with A23187 and carbonyl cyanide p-trifluoromethoxyphenylhydrazone indicated that the prostaglandin B1 oligomers were functioning as ionophores and the release of Ca2+ was not caused by an uncoupling of oxidative phosphorylation. The oligomers caused a major decrease in the membrane potential but only when the mitochondria were preloaded with exogenous Ca2+, and even then, the Ca2+ efflux was completed before the membrane potential decreased to less than 90 mV. The oligomeric molecules were able to form supramolecular aggregates in the presence of Ca2+ as detected by light scattering. They extracted Ca2+ into an organic phase, and translocated Ca2+ from one aqueous domain to another across an organic barrier; K+ and Na+ modulated these processes. The prostaglandin B1 derivatives also translocated Rb+ from one aqueous phase to another across an organic barrier when Ca2+ was translocated.     

Oogenesis and ovarian histology in two populations of the viviparous lizard Sceloporus grammicus (Squamata: Phrynosomatidae) from the central Mexican Plateau

The annual histological changes in ovarian morphology (oogenesis, follicular atresia, and corpus luteum) are described for the Mexican lizard Sceloporus grammicus, in two populations that inhabit contrasting environments (vegetation categories, climate, precipitation, and temperature) from Hidalgo State, Mexico. Two germinal beds were situated on the dorsal surface of each ovary of this species. In both the populations, oogenesis involves two major processes: previtellogenesis and vitellogenesis. The histological changes during previtellogenesis are similar to those for other reptilian sauropsids, whereas vitellogenesis differs and the features of this last process are described for the first time. In early previtellogenesis, primary oocytes have fibrillar chromosomes and the ooplasm stains slightly. The primordial follicles are surrounded by a granulosa composed of cuboidal follicular cells. During late previtellogenesis, the oocyte had an eccentric nucleus with lamp‐brush chromosomes and multiple nucleoli. The granulosa becomes multilayered and polymorphic, containing three cell types: small, intermediate, and pyriform. The zona pellucida was homogeneous and clearly observed. In early vitellogenesis, the oocyte showed several small acidophilic granules distributed in the center and the periphery of the oocyte. As vitellogenesis progresses, the yolk platelets move toward the central area of the oocyte and they fuse to form acidophilic and homogeneous yolk. Lipid droplets were distributed irregularly in the ooplasm of the oocyte. In Zacualtipán, the results revealed a strong seasonal reproductive activity. Females had vitellogenic follicles from July to September, and pregnant females were founded from September to March. In Tizayuca, the results showed an unusual pattern of reproductive activity. Females with vitellogenic follicles and pregnant females were found throughout the year, indicating continuous reproduction. We suggest that the observed differences in reproductive activity from these populations indicate adaptative fine tuning in response to local environmental conditions. These results contribute to the knowledge of variation in vitellogenesis and reproductive strategies of this species and among spiny lizards overall. J. Morphol. 275:949–960, 2014. © 2014 Wiley Periodicals, Inc.     

Non-specific immunity in rabbits infected with 10 strains of the rabbit haemorrhagic disease virus with different biological properties

To determine the parameters of non-specific immunity in rabbits infected with 10 biologically different strains of the rabbit haemorrhagic disease (RHD) virus (BS89, Hagenow, Rainham, Frankfurt, Asturias, Vt97, Triptis, Hartmannsdorf, Pv97, 9905 RHDVa) the following indices were assessed: polimorphonuclear cell (PMN) adherence capacity, absorption index, percentage of absorbing cells, spontaneous, stimulated as well as spectrophotometric test for reduction of the nitroblue tetrazolium (NBT), metabolic activity coefficient of neutrophilic granulocytes, stimulation index, myeloperoxidase activity, lysozyme concentration and activity index. The symptoms and the percentage of mortality in animals infected were recorded. On the basis of the estimated parameters, the present study confirmed the existence of immunotypes among the strains of the RHD virus. However, the results did not indicate a connection between biological property of the RHD virus (haemagglutination capacity and generation of antigenic variants) and the immunological profile of the strains.