Diversity of Siphonaria Sowerby I, 1823 (Gastropoda,Siphonariidae) in the Seychelles Bank and beyond

Molecular phylogenetic studies have shown that the characters of the reduced shell of the false limpets of the genus Siphonaria Sowerby I, 1823 are highly variable and often insufficient for species delimitation. The taxonomy and distribution of Siphonaria in the Indian Ocean are poorly known. We sampled Siphonaria in the Seychelles Bank to check the occurrence of recorded species using DNA sequences and to study the paths through which Siphonaria species have colonised the Seychelles Bank by reconstructing their phylogenetic relationships. Analyses of a dataset comprising 16 S rRNA gene sequences of 33 specimens from the Seychelles Bank and 300 additional Siphonaria sequences from other regions from GenBank with various methods for species delimitation resulted in 19–102 primary species hypotheses. Assemble Species by Automatic Partitioning provided a conservative estimate of the species number (42) in which several indisputable species were lumped. The results of Automatic Barcode Gap Discovery depended strongly on the assumed prior maximum intraspecific divergence, whereas the tree-based methods Generalised Mixed Yule Coalescent and Poisson Tree Processes resulted in high overestimates. The specimens from the Seychelles Bank represent three clades, belonging to the Siphonaria ‘atra’ group, the Siphonaria ‘normalis’ group and a possibly undescribed species recorded previously only from Hainan. At least two of the three species recorded from the Seychelles Bank came from the east, i.e., from the Coral Triangle in the Indo-Australian Archipelago, the region with the highest marine biodiversity worldwide. A major transport mechanism across the Indian Ocean was probably the South Equatorial Current.     

Systematic revision and molecular phylogeny of the land snail genus Fruticocampylaea (Gastropoda: Hygromiidae) from the Caucasus region

This paper presents a systematic revision and a molecular phylogenetic analysis of the Caucasian land snail genus Fruticocampylaea. The genus is newly delimited based on the reduction of the cavities adjoining the seminal duct in the penial papilla. Shell and genitalia of all five species (F. narzanensis, F. kobensis, F. tushetica sp. nov., F. christophori, F. daghestana) are described and figures provided. All synonyms and all locality records are listed. Maximum likelihood and Bayesian analyses of mitochondrial and nuclear DNA sequences (fragments of cox1, 16S rDNA, ITS2 and 28S rDNA) confirm the monophyly of Fruticocampylaea. The reduction of the dart apparatus and the conical plug, via which the dart apparatus inserts into the vagina, as well as the molecular phylogenetic analyses, suggests a sister group relationship between Fruticocampylaea and Circassina (without Abchasohela). Furthermore, the molecular phylogenetic analyses indicate that the Fruticocampylaea species originated in a rapid radiation. The uplift of the Greater Caucasus in the Late Miocene or Pliocene or climatic changes at the end of the Pliocene or in the early Pleistocene may have caused the radiation of Fruticocampylaea. Low intraspecific variability can be explained by population bottlenecks during Pleistocene glacial periods followed by postglacial population increase.

http://zoobank.org/urn:lsid:zoobank.org:pub:AB15158D-21A3-4945-8D49-F7DE8E406E2B     

Treatment with apolipoprotein A-1 mimetic peptide reduces lupus-like manifestations in a murine lupus model of accelerated atherosclerosis

Introduction

The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE^-/-Fas^-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.

Methods

Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.

Results

In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (P_{L, LP} < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (P_L < 0.05) and oxidized phospholipids (oxPLs) (P_{L, LP} < 0.005), and elevated total and vertebral bone mineral density (P_{L, LP} < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68⁺ macrophages (P_LP < 0.01), significantly increased mean α-actin stained area (P_LP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (P_{L, LP} < 0.0005) and VCAM-1 (P_L < 0.0002).

Conclusions

L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis.     

Molecular architecture of the ribosome‐bound Hepatitis C Virus internal ribosomal entry site RNA

Internal ribosomal entry sites (IRESs) are structured cis‐acting RNAs that drive an alternative, cap‐independent translation initiation pathway. They are used by many viruses to hijack the translational machinery of the host cell. IRESs facilitate translation initiation by recruiting and actively manipulating the eukaryotic ribosome using only a subset of canonical initiation factor and IRES transacting factors. Here we present cryo‐EM reconstructions of the ribosome 80S‐ and 40S‐bound Hepatitis C Virus (HCV) IRES. The presence of four subpopulations for the 80S•HCV IRES complex reveals dynamic conformational modes of the complex. At a global resolution of 3.9 Å for the most stable complex, a derived atomic model reveals a complex fold of the IRES RNA and molecular details of its interaction with the ribosome. The comparison of obtained structures explains how a modular architecture facilitates mRNA loading and tRNA binding to the P‐site. This information provides the structural foundation for understanding the mechanism of HCV IRES RNA‐driven translation initiation.     

High gene flow despite opposite chirality in hybrid zones between enantiomorphic door snails

We studied differentiation and geneflow patterns between enantiomorphic door‐snail species in two hybrid zones in the Bucegi Mountains (Romania) to investigate the effects of intrinsic barriers (complications in copulation) and extrinsic selection by environmental factors. A mitochondrial gene tree confirmed the historical separation of the examined populations into the dextral Alopia livida and the sinistral Alopia straminicollis in accordance with the morphological classification, but also indicated gene flow between the species. By contrast, a network based on amplified fragment length polymorphisms (AFLP) markers revealed local groups of populations as units independent of their species affiliation. Admixture analyses based on AFLP data showed that the genomes of most individuals in the hybrid zones are composed of parts of the genomes of both parental taxa. The introgression patterns of a notable fraction of the examined markers deviated from neutral introgression. However, the patterns of most non‐neutral markers were not concordant between the two hybrid zones. There was also no concordance between non‐neutral markers in the two genomic clines and markers that were correlated with environmental variables or markers that were correlated with the proportion of dextral individuals in the populations. Neither extrinsic selection by environmental factors nor intrinsic barriers resulting from positive frequency‐dependent selection of the prevailing coiling direction were sufficient to maintain the distinctness of A. straminicollis and A. livida. Despite being historically separated units, we conclude that these taxa now merge where they come into contact.     

Hormone-regulated expression and distribution of versican in mouse uterine tissues

Background  

Remodeling of the extracellular matrix is one of the most striking features observed in the uterus during the estrous cycle and after hormone replacement. Versican (VER) is a hyaluronan-binding proteoglycan that undergoes RNA alternative splicing, generating four distinct isoforms. This study analyzed the synthesis and distribution of VER in mouse uterine tissues during the estrous cycle, in ovariectomized (OVX) animals and after 17beta-estradiol (E2) and medroxyprogesterone (MPA) treatments, either alone or in combination.     

Increasing the number of molecular markers resolves the phylogenetic relationship of ‘Cepaea’ vindobonensis (Pfeiffer 1828) with Caucasotachea Boettger 1909 (Gastropoda: Pulmonata: Helicidae)

‘Cepaea’ vindobonensis has been shown to be closely related to Caucasotachea in recent molecular studies. The phylogenetic relationships within this clade and especially the phylogenetic position of ‘Cepaea’ vindobonensis were, however, not well resolved. Our phylogenetic analyses on the basis of an increased number of molecular genetic loci from the mitochondrial and nuclear genomes unambiguously demonstrate that ‘Cepaea’ vindobonensis represents the sister group of the Caucasotachea taxa, with C. leucoranea from the Caspian region of Azerbaijan and Iran being the sister species of the remaining Caucasian and eastern Pontic Caucasotachea species. We argue for the inclusion of ‘Cepaea’ vindobonensis in Caucasotachea rather than for a re‐erection of a monotypic genus Austrotachea for the species because of the overall low degree of morphological differentiation and the low number of species in the group.