Radula and Shell Microstructure Variations are Congruent with a Molecular Estimate of Shallow-Water Japanese Chitons.

Variations of the radula and shell microstructures in 33 species of Japanese chiton were investigated along with molecular phylogenetic trees. The molecular phylogenetic trees indicated that Chitonida was composed of four clades, of which two clades formed Acanthochitonina and corresponded to Mopalioidea and Cryptoplacoidea, respectively, and the other clades formed Chitonina. In the radula, the shapes of the central and centro-lateral teeth and the petaloid process varied greatly among species or genera and were useful for the identification of particular species or genera. The presence of accessory and petaloid processes and the cusp shape were relatively conserved and useful for recognizing particular genera or even suborders. In the valves, four to six shell layers were found at the section, but the ventral mesostracum was not observed in Acanthochitonina. The shell microstructures in the ventral sublayer of the tegmentum varied at suborder, but those in the other layers were almost constant. The megalaesthete chamber type varied at superfamily and was helpful to identify particular families or superfamilies. The characteristics of the shell layers and shell microstructures appear to be a synapomorphy shared by the members of Acanthochitonina. The classification within Chitonina needs to be reexamined because the variations of the cusp shape and megalaesthete chamber type were relatively large and did not correspond to the current classification. Callochiton formed a sister group with Chitonida and would be equally closely related to Chitonina and Acanthochitonina because of possessing a mosaic of characteristics from both.

Molecular Identification and Phylogenetic Analysis of Laelapidae Mites (Acari: Mesostigmata).

The family Laelapidae (Dermanyssoidea) is morphologically and ecologically the most diverse group of Mesostigmata mites. Although molecular genetic data are widely used in taxonomic identification and phylogenetic analysis, most classifications in Mesostigmata mites are based solely on morphological characteristics. In the present study, eight species of mites from the Laelapidae (Dermanyssoidea) family collected from different species of small rodents in Lithuania, Norway, Slovakia, and the Czech Republic were molecularly characterized using the nuclear (28S ribosomal RNA) and mitochondrial (cytochrome oxidase subunit I gene) markers. Obtained molecular data from 113 specimens of mites were used to discriminate between species and investigate the phylogenetic relationships and genetic diversity among Laelapidae mites from six genera. This study provides new molecular data on Laelaps agilis, Laelaps hilaris, Laelaps jettmari, Haemogamasus nidi, Eulaelaps stabularis, Hyperlaelaps microti, Myonyssus gigas, and Hirstionyssus sp. mites collected from different rodent hosts and geographical regions in Europe.

Genetic assessment of the variation and distribution of the species of Salinator (Panpulmonata: Amphibolidae) in south-eastern Australia.

Amphibolidae is one of the most abundant families of gastropods in estuarine environments of south-eastern Australia. However, the range limits of the species of Salinator, one of the family's two genera in the region, remain unclear partly due to uncertainty of identifications based solely on shell morphology. Insufficient data have been collected to address questions regarding the genetic variability of any of the species of Salinator. Here, DNA sequences from a segment of the cytochrome c oxidase subunit I and 28S ribosomal RNA genes were collected to investigate the distribution and variation of the three Salinator species in the region, these being S. fragilis, S. rhamphidia and S. tecta. The results demonstrate a large range extension in S. rhamphidia and suggest that S. tecta may have limited distribution in Tasmania. In contrast to previously-studied estuarine Mollusca in the south-eastern coasts of the mainland and Tasmania, S. rhamphidia has regional differentiation. There is evidence of genetic disequilibrium within S. fragilis, suggesting that it may presently comprise contributions from two distinct sets of populations.

Algal Lymphadenitis in a Dog Caused by Scenedesmus Species.

A 6-year-old, spayed female Labrador/Weimaraner cross-breed dog that had previously lived in Arizona presented in Montana for an annual examination with an incidentally enlarged popliteal lymph node, which was subsequently biopsied. Histologically, the lymph node was expanded by eosinophil-rich granulomas with both extracellular and intrahistiocytic green algae. These algae had intracytoplasmic, birefringent, and refractile granules; readily formed 2 to 3 mm green colonies on Columbia blood agar medium; and ultrastructurally had a multilayered cell wall and intracytoplasmic chloroplasts. Amplified product from the internal transcribed spacer and D1/D2 regions of the 28S ribosomal RNA gene had high sequence identity to Scenedesmus sp. Despite similar infection in the retropharyngeal lymph node 1 year later, the animal remained otherwise healthy with no clinical signs. To the authors' knowledge, this is the first case of Scenedesmus species infection in a dog and is a differential diagnosis for Coccidioides immitis.

Cell Death-Associated Ribosomal RNA Cleavage in Postmortem Tissues and Its Forensic Applications.

Estimation of postmortem interval (PMI) is a key issue in the field of forensic pathology. With the availability of quantitative analysis of RNA levels in postmortem tissues, several studies have assessed the postmortem degradation of constitutively expressed RNA species to estimate PMI. However, conventional RNA quantification as well as biochemical and physiological changes employed thus far have limitations related to standardization or normalization. The present study focuses on an interesting feature of the subdomains of certain RNA species, in which they are site-specifically cleaved during apoptotic cell death. We found that the D8 divergent domain of ribosomal RNA (rRNA) bearing cell death-related cleavage sites was rapidly removed during postmortem RNA degradation. In contrast to the fragile domain, the 5' terminal region of 28S rRNA was remarkably stable during the postmortem period. Importantly, the differences in the degradation rates between the two domains in mammalian 28S rRNA were highly proportional to increasing PMI with a significant linear correlation observed in mice as well as human autopsy tissues. In conclusion, we demonstrate that comparison of the degradation rates between domains of a single RNA species provides quantitative information on postmortem degradation states, which can be applied for the estimation of PMI.

Integrative Taxonomy Recognizes Evolutionary Units Despite Widespread Mitonuclear Discordance: Evidence from a Rotifer Cryptic Species Complex.

Mitonuclear discordance across taxa is increasingly recognized as posing a major challenge to species delimitation based on DNA sequence data. Integrative taxonomy has been proposed as a promising framework to help address this problem. However, we still lack compelling empirical evidence scrutinizing the efficacy of integrative taxonomy in relation to, for instance, complex introgression scenarios involving many species. Here, we report remarkably widespread mitonuclear discordance between about 15 mitochondrial and 4 nuclear Brachionus calyciflorus groups identified using different species delimitation approaches. Using coalescent-, Bayesian admixture-, and allele sharing-based methods with DNA sequence or microsatellite data, we provide strong evidence in support of hybridization as a driver of the observed discordance. We then describe our combined molecular, morphological, and ecological approaches to resolving phylogenetic conflict and inferring species boundaries. Species delimitations based on the ITS1 and 28S nuclear DNA markers proved a more reliable predictor of morphological variation than delimitations using the mitochondrial COI gene. A short-term competition experiment further revealed systematic differences in the competitive ability between two of the nuclear-delimited species under six different growth conditions, independent of COI delimitations; hybrids were also observed. In light of these findings, we discuss the failure of the COI marker to estimate morphological stasis and morphological plasticity in the B. calyciflorus complex. By using B. calyciflorus as a representative case, we demonstrate the potential of integrative taxonomy to guide species delimitation in the presence of mitonuclear phylogenetic conflicts.

Testing a Microarray to Detect and Monitor Toxic Microalgae in Arcachon Bay in France.

Harmful algal blooms (HABs) occur worldwide, causing health problems and economic damages to fisheries and tourism. Monitoring agencies are therefore essential, yet monitoring is based only on time-consuming light microscopy, a level at which a correct identification can be limited by insufficient morphological characters. The project MIDTAL (Microarray Detection of Toxic Algae)-an FP7-funded EU project-used rRNA genes (SSU and LSU) as a target on microarrays to identify toxic species. Furthermore, toxins were detected with a newly developed multiplex optical Surface Plasmon Resonance biosensor (Multi SPR) and compared with an enzyme-linked immunosorbent assay (ELISA). In this study, we demonstrate the latest generation of MIDTAL microarrays (version 3) and show the correlation between cell counts, detected toxin and microarray signals from field samples taken in Arcachon Bay in France in 2011. The MIDTAL microarray always detected more potentially toxic species than those detected by microscopic counts. The toxin detection was even more sensitive than both methods. Because of the universal nature of both toxin and species microarrays, they can be used to detect invasive species. Nevertheless, the MIDTAL microarray is not completely universal: first, because not all toxic species are on the chip, and second, because invasive species, such as Ostreopsis, already influence European coasts.