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Molecular Evidence (molecular + evidence)
Selected AbstractsMOLECULAR EVIDENCE FOR THE ORIGIN OF WORKERLESS SOCIAL PARASITES IN THE ANT GENUS POGONOMYRMEXEVOLUTION, Issue 10 2002Joel D. Parker Abstract., Speciation of two social parasites from their respective hosts is tested using a molecular phylogeny. Alignment of 711 DNA base pairs of mitochondrial cytochrome b gene was used to assess phylogenetic relationships of inquiline species to their hosts and to other members of the genus. We show that the inquiline social parasites of the North American seed harvester ants are monophyletic, descending from one of the known hosts (Pogonomyrmex barbatus) in the recent past and shifting hosts in a pattern similar to that observed in other Hymenopteran social parasites. In addition, the host populations unexpectedly were found to be polyphyletic. Populations of Pogonomyrmex rugosus from an area east of the Chiricahua Mountains in Southern Arizona belong to a mitochondrial clade separate from the more western clade of P. rugosus from the Sonoran and Chihuahuan Deserts. Evidence of mitochondrial DNA introgression between P. rugosus and P. barbatus was also observed. We conclude that Emery's rule does not strictly hold for this system, but that the hosts and parasites are very closely related, supporting a loose definition of Emery's rule. [source] Molecular Evidence for Persistence of Anaplasma phagocytophilum in the Absence of Clinical Abnormalities in Horses after Recovery from Acute Experimental InfectionJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2009P. Franzén Background: Anaplasma phagocytophilum infects several mammalian species, and can persist in sheep, dogs, and calves. However, whether this organism persists in horses or induces long-term clinical abnormalities is not known. Objectives: To evaluate whether A. phagocytophilum can persist in horses and to document clinical findings for 3 months after complete recovery from acute disease. Animals: Five clinically normal adult horses that had recovered spontaneously from experimentally induced acute disease caused by a Swedish equine isolate of A. phagocytophilum. Methods: Horses were monitored for up to 129 days post inoculation (PI) by daily clinical examination and at least alternate day blood sampling for evidence of A. phagocytophilum on polymerase chain reaction (PCR) and blood smears. All horses were euthanized and underwent postmortem examination. Results: All horses were periodically PCR positive after recovery from acute infection. Before day 66 PI 2 horses were persistently PCR negative whereas 3 horses were intermittently PCR positive. Subsequently, 4 of 5 horses were intermittently PCR positive, particularly after stress mimicking interventions. One animal was positive immediately before postmortem examination. Clinical abnormalities related to persistence of anaplasma were not observed. No specific changes were found at postmortem examination, and all sampled tissues from all horses were negative on PCR for A. phagocytophilum. Conclusions and Clinical Importance: Infection with A. phagocytophilum can persist in the horse for at least 129 days. However, the continued presence of the organism is not associated with detectable clinical or pathological abnormalities. [source] Molecular Evidence that Phylogenetically Diverged Ciliates Are Active in Microbial Mats of Deep-Sea Cold-Seep SedimentTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 1 2010KIYOTAKA TAKISHITA ABSTRACT. Cold seeps are areas of the seafloor where hydrogen sulfide- and methane-rich fluid seepage occurs, often sustaining chemosynthetic ecosystems. It is well known that both archaea and bacteria oxidize sulfides and methane to produce chemical energy and that several endemic animals use this energy to thrive in cold seeps. On the other hand, there is little knowledge regarding diversity and ecology of microbial eukaryotes in this ecosystem. In this study we isolated environmental RNA and DNA from microbial mats of cold-seep sediment in Sagami Bay, Japan, and retrieved eukaryotic small-subunit ribosomal RNA sequences with polymerase chain reaction methods followed by clone library construction. Most RNA-derived clones obtained were from ciliates, although DNA-derived clones were mainly from the fungus Cryptococcus curvatus, suggesting that ciliates are active in the environment. The ciliate sequences were phylogenetically diverse, and represented eight known class lineages as well as undesignated lineages. Because most ciliates are bacterivorous, it is highly likely that the ciliates for which sequences were recovered play a role in the food web of this ecosystem as grazers of microbial mats. In addition, given that the environment studied is under highly reduced (anoxic) conditions, based on the prokaryotic community structure deduced from T-RFLP profiles, the ciliates detected may be obligatory or facultative anaerobes. [source] Morphological and Molecular Evidence of Arbuscular Mycorrhizal Fungal Associations in Costa Rican Epiphytic Bromeliads,BIOTROPICA, Issue 2 2005Annette R. Rowe ABSTRACT Arbuscular mycorrhizal fungi influence the growth, morphology, and fitness of a variety of plant species, but little is known of the arbuscular mycorrhizal (AM) fungal associations of plant species in forest canopies. Plant species' associations with AM fungi are most often elucidated by examining the roots for fungal structures; however, morphological data may provide a limited resolution on a plant's mycorrhizal status. We combined a traditional staining technique with a molecular marker (the 18S ribosomal gene) to determine whether or not a variety of epiphytic bromeliads form arbuscular mycorrhizal fungal associations. Using these methods we show that the epiphytic bromeliad Vriesea werkleana forms arbuscular mycorrhizal fungal associations with members of the genus Glomus. AM fungal sequences of this plant species formed three distinct clades nested within a larger Glomus clade; two of the clades did not group with any previously sequenced lineage of Glomus. Novel clades may represent novel species. Although Vriesea werkleana is associated with multiple AM fungal species, each individual plant is colonized by a single lineage. The combination of morphological and molecular methods provides a practical approach to the characterization of the mycorrhizal status of epiphytic bromeliads, and perhaps other tropical epiphytes. [source] Molecular evidence for widespread occurrence of Foraminifera in soilsENVIRONMENTAL MICROBIOLOGY, Issue 9 2010Franck Lejzerowicz Summary Environmental SSU rDNA-based surveys are contributing to the dramatic revision of eukaryotic high-level diversity and phylogeny as the number of sequence data increases. This ongoing revolution gives the opportunity to test for the presence of some eukaryotic taxa in environments where they have not been found using classical microscopic observations. Here, we test whether the foraminifera, a group of single-celled eukaryotes, considered generally as typical for the marine ecosystems are present in soil. We performed foraminiferal-specific nested PCR on 20 soil DNA samples collected in contrasted environments. Unexpectedly, we found that the majority of the samples contain foraminiferal SSU rDNA sequences. In total, we obtained 49 sequences from 17 localities. Phylogenetic analysis clusters them in four groups branching among the radiation of early foraminiferal lineages. Three of these groups also include sequences originated from previous freshwater surveys, suggesting that there were up to four independent colonization events of terrestrial and/or freshwater ecosystems by ancestral foraminifera. As shown by our data, foraminifera are a widespread and diverse component of soil microbial communities. Yet, identification of terrestrial foraminiferal species and understanding of their ecological role represent an exciting challenge for future research. [source] Molecular evidence-based medicineEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2007Evolution, integration of information in the genomic era Abstract Evidence-based medicine and molecular medicine have both been influential in biomedical research in the last 15 years. Despite following largely parallel routes to date, the goals and principles of evidence-based and molecular medicine are complementary and they should be converging. I define molecular evidence-based medicine as the study of medical information that makes sense of the advances of molecular biological disciplines and where errors and biases are properly appreciated and placed in context. Biomedical measurement capacity improves very rapidly. The exponentially growing mass of hypotheses being tested requires a new approach to both statistical and biological inference. Multidimensional biology requires careful exact replication of research findings, but indirect corroboration is often all that is achieved at best. Besides random error, bias remains a major threat. It is often difficult to separate bias from the spirit of scientific inquiry to force data into coherent and ,significant' biological stories. Transparency and public availability of protocols, data, analyses and results may be crucial to make sense of the complex biology of human disease and avoid being flooded by spurious research findings. Research efforts should be integrated across teams in an open, sharing environment. Most research in the future may be designed, performed, and integrated in the public cyberspace. [source] Exploring the "two-hit hypothesis" in NF2: Tests of two-hit and three-hit models of vestibular schwannoma developmentGENETIC EPIDEMIOLOGY, Issue 4 2003Ryan Woods Abstract Neurofibromatosis 2 (NF2) is a genetic disease that occurs in approximately 1 in 40,000 live births. Almost all affected individuals develop bilateral tumors of Schwann cells that surround the vestibular nerves; these tumors are known as vestibular schwannomas (VS). Evidence from molecular genetic studies suggests that at least two mutations are involved in formation of VS in patients with NF2. Several authors proposed probabilistic models for this process in other tumors, and showed that such models are consistent with incidence data. We evaluated two different probabilistic models for a "2-hit" hypothesis for VS development in NF2 patients, and we present results from fitting these models to incidence data. Molecular evidence does not exclude the possibility that additional hits are necessary for the development of VS, and we also assessed a "3-hit" model for tumor formation. The "3-hit" model fits the data marginally better than one of the "2-hit" models and much better than the other "2-hit" model. Our findings suggest that more than two mutations may be necessary for VS development in NF2 patients. Genet Epidemiol 24:265,272, 2003. © 2003 Wiley-Liss, Inc. [source] Molecular evidence for dispersal rather than vicariance as the origin of flightless insect species on the Chatham Islands, New ZealandJOURNAL OF BIOGEOGRAPHY, Issue 5 2000Steven A. Trewick Abstract Aim The aim was to use mitochondrial DNA sequence data to test between vicariance and oversea dispersal explanations for the origin of the Chatham Islands biota. Location New Zealand and the Chatham Islands, separated by c. 800 km in the south-west Pacific Ocean. Methods DNA sequences from the mitochondrial gene cytochrome oxidase I (COI) were obtained from four genera of relatively large and flightless insects (Coleoptera, Geodorcus, Mecodema; Orthoptera,Talitropsis; Blattoidea,Celatoblatta). These were used to test alternative hypotheses for the origin of the Chatham taxa. Results Phylogenetic analysis revealed the Chatham taxa in each genus to be monophyletic. Genetic distances exhibited by these genera, between taxa found on the Chatham Islands and mainland New Zealand were relatively low (11.2, 2.8, 3.0 and 4.9%, respectively). Main conclusions Even allowing for variation in molecular evolutionary rates, these genetic distances indicate phylogenetic separation of New Zealand and Chatham insect lineages in the Pliocene (2,6 Ma). Such dates are more than one order of magnitude too recent to be explained by vicariant (tectonic) processes. Oversea dispersal from New Zealand to the Chatham Islands is implicated and this conclusion is in keeping with the taxonomy of the endemic avifauna, flora and fossil molluscan fauna. [source] Molecular evidence for a founder effect in invasive house finch (Carpodacus mexicanus) populations experiencing an emergent disease epidemicMOLECULAR ECOLOGY, Issue 1 2006DANA M. HAWLEY Abstract The impact of founder events on levels of genetic variation in natural populations remains a topic of significant interest. Well-documented introductions provide a valuable opportunity to examine how founder events influence genetic diversity in invasive species. House finches (Carpodacus mexicanus) are passerine birds native to western North America, with the large eastern North American population derived from a small number of captive individuals released in the 1940s. Previous comparisons using amplified fragment length polymorphism (AFLP) markers found equivalent levels of diversity in eastern and western populations, suggesting that any genetic effects of the founder event were ameliorated by the rapid growth of the newly established population. We used an alternative marker system, 10 highly polymorphic microsatellites, to compare levels of genetic diversity between four native and five introduced house finch populations. In contrast to the AFLP comparisons, we found significantly lower allelic richness and heterozygosity in introduced populations across all loci. Three out of five introduced populations showed significant reductions in the ratio of the number of alleles to the allele size range, a within-population characteristic of recent bottlenecks. Finally, native and introduced populations showed significant pairwise differences in allele frequencies in every case, with stronger isolation by distance within the introduced than native range. Overall, our results provide compelling molecular evidence for a founder effect during the introduction of eastern house finches that reduced diversity levels at polymorphic microsatellite loci and may have contributed to the emergence of the Mycoplasma epidemic which recently swept the eastern range of this species. [source] Molecular evidence for deep phylogenetic divergence in Mandrillus sphinxMOLECULAR ECOLOGY, Issue 7 2003P. T. Telfer Abstract Mandrills (Mandrillus sphinx) are forest primates indigenous to western central Africa. Phylogenetic analysis of 267 base pairs (bp) of the cytochrome b gene from 53 mandrills of known and 17 of unknown provenance revealed two phylogeographical groups, with haplotypes differentiated by 2.6% comprising seven synonymous transitions. The distribution of the haplotypes suggests that the Ogooué River, Gabon, which bisects their range, separates mandrill populations in Cameroon and northern Gabon from those in southern Gabon. The haplotype distribution is also concordant with that of two known mandrill simian immunodeficiency viruses, suggesting that these two mandrill phylogroups have followed different evolutionary trajectories since separation. [source] Molecular evidence for the identity of the Magenta petrelMOLECULAR ECOLOGY RESOURCES, Issue 2 2009HAYLEY A. LAWRENCE Abstract A lone petrel was shot from the decks of an Italian warship (the ,Magenta') while it was sailing the South Pacific Ocean in 1867, far from land. The species, unknown to science, was named the ,Magenta petrel' (Procellariiformes, Procellariidae, Pterodroma magentae). No other specimens of this bird were collected and the species it represented remained a complete enigma for over 100 years. We compared DNA sequence of the mitochondrial cytochrome b gene from the Magenta petrel to that of other petrels using phylogenetic methods and ancient DNA techniques. Our results strongly suggest that the Magenta petrel specimen is a Chatham Island taiko. Furthermore, given the collection location of the Magenta petrel, our finding indicates that the Chatham Island taiko forages far into the Pacific Ocean (near South America). This has implications for the conservation of the taiko, one of the world's rarest seabirds. [source] Molecular evidence for multiple polyploidization and lineage recombination in the Chrysanthemum indicum polyploid complex (Asteraceae)NEW PHYTOLOGIST, Issue 4 2006Wenhua Yang Summary ,,The Chrysanthemum indicum polyploid complex comprises morphologically differentiated diploids, tetraploids and hybrids between C. indicum and C. lavandulifolium. The relationships between species and cytotypes within this complex remain poorly understood. ,,Random amplified polymorphic DNAs (RAPDs), intersimple sequence repeats (ISSRs) and chloroplast SSR markers were used to elucidate the genetic diversity and relationships of the C. indicum polyploid complex. ,,Molecular analysis of three diploid and nine tetraploid populations provided strong evidence for recurrent origins and lineage recombination in the C. indicum polyploid complex. The high similarity in molecular marker profiles and cpDNA haplotypes between the diploids and tetraploids distributed in the Shen-Nong-Jia Mountain area of China suggested an autopolyploid origin of the tetraploids, while the tetraploids from other populations may have originated via allopolyploidization. Lineage recombination was revealed by the extensive sharing of chloroplast haplotypes and genetic markers among the tetraploid populations with different origins. ,,Multiple differentiation and hybridization/polyploidization cycles have led to an evolutionary reticulation in the C. indicum polyploid complex, and resulted in the difficulties in systematic classification. [source] Molecular evidence for Apple stem pitting virus infection in IndiaPLANT PATHOLOGY, Issue 2 2010S. Dhir No abstract is available for this article. [source] Molecular evidence suggests an ancient radiation for the fairy shrimp genus Streptocephalus (Branchiopoda: Anostraca)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2004SAVEL R. DANIELS Phylogenetic relationships among assumed Gondwanan aquatic inland invertebrate fauna are generally largely neglected, and biogeographical hypotheses for these organisms are generally inferred from historic (palaeogeographical) and contemporary distribution patterns. The distribution of the monogeneric thermophilic freshwater fairy shrimp family Streptocephalidae (Streptocephalus) provides a particularly useful framework to test the three contrasting biogeographical scenarios proposed for the evolution of this group: (1) the genus evolved in Laurasia and subsequently dispersed into Africa and North America; (2) the genus evolved and dispersed out of Africa and (3) the current distribution of the genus is the result of vicariance following the fragmentation of Gondwana. In the present study, the phylogenetic relationships of species in this genus are examined with the use of two mitochondrial genes (12S rRNA and COI mtDNA), while the phylogenetic relationships among the North American species and selected African taxa was investigated using the nuclear fragment (5.8S-ITS-1-18S). Phylogenetic results indicate that Streptocephalus probably evolved in Gondwana and that the current distribution patterns are a consequence of a combination of vicariance and limited dispersal. The implications for the evolution of continental freshwater crustaceans are discussed. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82, 313,327. [source] Molecular evidence for the hybrid origin of a new endemic species of Stylosanthes Sw. (Fabaceae) from the Mexican Yucatán PeninsulaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2002JACQUELINE VANDER STAPPEN Stylosanthes aff. calcicola is a formally undescribed tetraploid species from the Mexican Yucatán Peninsula, showing morphological similarities to the diploid species S. calcicola, but distinct in a number of characters. We used uni- and biparentally inherited molecular markers to infer the hybrid origin of this species in relation to known diploid species of Stylosanthes. Molecular characterization was based on length and/or DNA sequence variation of nuclear sequence-tagged site (STS) markers, the internal transcribed spacer (ITS) region of nuclear rDNA and the trnL intron of chloroplast DNA (cpDNA). Stylosanthes aff. calcicola contains a distinct cpDNA haplotype and nuclear DNA fragment, with closest relationship to the diploid species S. calcicola. In contrast, the DNA sequences of two nuclear loci reveal a closer relationship to the diploid species S. angustifolia, S. hispida, S. humilis, S. leiocarpa and S. viscosa. The majority of the STS markers showed additivity of PCR fragments in S. aff. calcicola, representing the combination of two genetically different genomes. We postulate that S. aff. calcicola is a distinct species of allotetraploid origin that appears to have originated once from hybridization between two divergent genomes, of which the maternal and paternal parent are closely related to, or derived from, a member of the lineages represented by S. calcicola and S. viscosa, respectively. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 140, 1,13. [source] Regional heterogeneity in the developing palate: morphological and molecular evidence for normal and abnormal palatogenesisCONGENITAL ANOMALIES, Issue 2 2006Junko Okano ABSTRACT Development of the mammalian secondary palate involves the growth, elevation, medial elongation and midline fusion of palatal shelves. Recent morphological and molecular studies on palatogenesis suggest that the developing palate is not a homogeneous organ but each part may behave differently during organogenesis. Especially, some key molecules involved in palate development have been shown to exhibit heterogeneous patterns of expression in the palatal tissue. Therefore it seems necessary to recognize the regional heterogeneity of the developing palate along the dorsoventral and anteroposterior axes when analyzing the mechanisms of normal and abnormal morphogenesis. Based on recent studies, we discuss the issue of the regional heterogeneity in the fetal palate and propose a principle that divides the fetal palate into several regions from the morphological and molecular standpoint. [source] The mushroom bodies , prominent brain centres of arthropods and annelids with enigmatic evolutionary originACTA ZOOLOGICA, Issue 1 2010Rudi Loesel Abstract Loesel, R. and Heuer, C.M. 2010. The mushroom bodies , prominent brain centres of arthropods and annelids with enigmatic evolutionary origin. ,Acta Zoologica (Stockholm) 91: 29,34 Mushroom bodies (MBs) are the most prominent and conspicuous neuropils in the brain of arthropods, onychophorans and vagile polychaete annelids but have not been described in any other animal group with complex brain architecture. Due to a number of unique neuroanatomical characters MBs can easily be identified and distinguished from other brain centres. However, their evolutionary origin and the question whether MBs are homologous structures is still under debate. This paper will briefly summarize the available morphological data and their implications with respect to the molecular evidence on early metazoan radiation. Unraveling the origin of MBs is an example of the challenges neurophylogenists will face in the future, especially so since it will signify a major step towards reconstructing early metazoan brain evolution. [source] Functional and molecular evidence of adenosine A2A receptor in coronary arteriolar dilation to adenosineDRUG DEVELOPMENT RESEARCH, Issue 1-2 2001Lih Kuo Abstract Adenosine is a potent vasodilator implicated in the regulation of coronary microvascular diameter during metabolic stress. However, the specific adenosine receptors and underlying mechanism responsible for the dilation of coronary microvessels to adenosine remains to be elucidated. Thus, pig subepicardial coronary arterioles (<100 ,m) were isolated, cannulated, and pressurized without flow for in vitro study. All vessels developed basal tone and dilated concentration-dependently to adenosine. Disruption of endothelium and inhibition of nitric oxide (NO) synthase by L-NAME produced identical attenuation of adenosine-induced dilation. KATP channel inhibitor glibenclamide further reduced the dilation of denuded vessels. cAMP antagonist Rp-8-Br-cAMP blocked vasodilation to forskolin, but failed to inhibit vasodilation to adenosine. Coronary dilation to adenosine was blocked by a selective adenosine A2A receptor antagonist ZM241385, but was not altered by an A1 receptor antagonist, DPCPX. Reverse transcription-polymerase chain reaction study revealed that A2A receptor mRNA was expressed in microvessels but not in cardiac myocytes; A1 receptor expression was observed only in cardiac myocytes. These results suggest that adenosine-induced dilation of coronary arterioles is mediated predominantly by A2A receptors. Activation of these receptors elicits vasodilation by endothelial release of NO and by smooth muscle opening of KATP channels in a cAMP-independent manner. Drug Dev. Res. 52:350,356, 2001. © 2001 Wiley-Liss, Inc. [source] Seasonal and substrate preferences of fungi colonizing leaves in streams: traditional versus molecular evidenceENVIRONMENTAL MICROBIOLOGY, Issue 2 2005Liliya G. Nikolcheva Summary Aquatic hyphomycetes are the main fungal decomposers of plant litter in streams. We compared the importance of substrate (three leaf species, wood) and season on fungal colonization. Substrates were exposed for 12 4-week periods. After recovery, mass loss, fungal biomass and release of conidia by aquatic hyphomycetes were measured. Fungal communities were characterized by counting and identifying released conidia and by extracting and amplifying fungal DNA (ITS2), which was subdivided into phylotypes by denaturing gradient gel electrophoresis (DGGE) and terminal-restriction fragment length polymorphism (T-RFLP). Mass loss, fungal biomass and reproduction were positively correlated with stream temperature. Conidial diversity was highest between May and September. Numbers of different phylotypes were more stable. Principal coordinate analyses (PCO) and canonical analyses of principal coordinates (CAP) of presence/absence data (DGGE bands, T-RFLP peaks and conidial species) showed a clear seasonal trend (P, 0.002) but no substrate effect (P, 0.88). Season was also a significant factor when proportional similarities of conidial communities or relative intensities of DGGE bands were evaluated (P, 0.003). Substrate was a significant factor determining DGGE band intensities (P = 0.002), but did not significantly affect conidial communities (P = 0.50). Both traditional and molecular techniques suggest that strict exclusion of fungi by substrate type is rare, and that presence of different species or phylotypes is governed by season. Biomasses of the various taxa (based on DGGE band intensities) were related to substrate type. [source] Molecular evidence-based medicineEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2007Evolution, integration of information in the genomic era Abstract Evidence-based medicine and molecular medicine have both been influential in biomedical research in the last 15 years. Despite following largely parallel routes to date, the goals and principles of evidence-based and molecular medicine are complementary and they should be converging. I define molecular evidence-based medicine as the study of medical information that makes sense of the advances of molecular biological disciplines and where errors and biases are properly appreciated and placed in context. Biomedical measurement capacity improves very rapidly. The exponentially growing mass of hypotheses being tested requires a new approach to both statistical and biological inference. Multidimensional biology requires careful exact replication of research findings, but indirect corroboration is often all that is achieved at best. Besides random error, bias remains a major threat. It is often difficult to separate bias from the spirit of scientific inquiry to force data into coherent and ,significant' biological stories. Transparency and public availability of protocols, data, analyses and results may be crucial to make sense of the complex biology of human disease and avoid being flooded by spurious research findings. Research efforts should be integrated across teams in an open, sharing environment. Most research in the future may be designed, performed, and integrated in the public cyberspace. [source] TOWARD A REALISTIC MODEL OF MUTATIONS AFFECTING FITNESSEVOLUTION, Issue 3 2003Peter D. Keightley Abstract Analysis of a recent mutation accumulation (MA) experiment has led to the suggestion that as many as one-half of spontaneous mutations in Arabidopsis are advantageous for fitness. We evaluate this in the light of data from other MA experiments, along with molecular evidence, that suggest the vast majority of new mutations are deleterious. [source] Lipomatous hemangiopericytoma of the head and neck: immunohistochemical and dna ploidy analysesHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2004Sadir J. Alrawi MD Abstract Background. Lipomatous hemangiopericytoma (LHPC) is a newly described rare soft tissue tumor with unpredictable biologic behavior and is difficult to diagnose by conventional histologic parameters. The molecular analyses of this entity to date are sparse. Only a few cases of LHPC have been reported. Although one case of LHPC in the sinonasal region was briefly reported, this is the first case in the head and neck region with detailed clinicopathologic features and molecular analysis of this entity. Methods. We reported a case of LHPC in a 55-year-old woman with a slowly growing lesion in the occipital area that was diagnosed by CT and MRI and removed surgically. Immunohistochemical and DNA ploidy analyses were performed. Results. A panel of 16 markers was included for immunohistochemical analysis. Diffuse immunopositivity of CD57 in our case provides supportive evidence that LHPC is linked with HPC because this marker is also present in approximately 50% of conventional HPCs. CD57 should be used in the immunohistochemical panel in any lesion suspected to be LHPC. Furthermore, CD57 along with CD34 and XIIIa is thought to stain for primitive mesenchymal stem cells, suggesting a bimodal/multimodal differentiation of LHPC. By flow cytometry, we found that tumor cells were 100% diploid with the S-phase fraction (SPF) being 3.21%. A significant positive correlation was detected between nuclear proliferating index and SPF (p < 0.001, by Spearman analysis). These findings provide molecular evidence indicating a benign nature of LHPC. Conclusions. Contrary to the old belief that HPC has an aggressive nature, this variant of tumor looks less aggressive. The patient was followed for 1 year without any evidence of recurrence, supporting our pathologic hypothesis. © 2004 Wiley Periodicals, Inc. Head Neck26: 544,549, 2004 [source] T cell lymphocytosis associated with polymyositis, myasthenia gravis and thymomaINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 5 2000S.H. Otton Summary Peripheral T cell lymphocytosis is a rare finding in association with malignant thymomas. In the majority of previous cases, the tumours have behaved aggressively with symptoms arising from local invasion. We describe a patient with ocular myasthenia gravis who presented with a rapidly progressive polymyositis and neuropathy and who was subsequently found to have a thymic mass and a mild T cell lymphocytosis. The thymoma did not give rise to local symptoms and showed no evidence of progression over a 14-month period of follow-up. The possibility of an underlying thymic tumour should be considered in any patient with chronic T cell lymphocytosis if the circulating cells show mature morphology and there is no molecular evidence of monoclonality. [source] On bivalve phylogeny: a high-level analysis of the Bivalvia (Mollusca) based on combined morphology and DNA sequence dataINVERTEBRATE BIOLOGY, Issue 4 2002Gonzalo Giribet Abstract. Bivalve classification has suffered in the past from the crossed-purpose discussions among paleontologists and neontologists, and many have based their proposals on single character systems. More recently, molecular biologists have investigated bivalve relationships by using only gene sequence data, ignoring paleontological and neontological data. In the present study we have compiled morphological and anatomical data with mostly new molecular evidence to provide a more stable and robust phylogenetic estimate for bivalve molluscs. The data here compiled consist of a morphological data set of 183 characters, and a molecular data set from 3 loci: 2 nuclear ribosomal genes (18S rRNA and 28S rRNA), and 1 mitochondrial coding gene (cytochrome c oxidase subunit I), totaling ,3 Kb of sequence data for 76 molluscs (62 bivalves and 14 outgroup taxa). The data have been analyzed separately and in combination by using the direct optimization method of Wheeler (1996), and they have been evaluated under 12 analytical schemes. The combined analysis supports the monophyly of bivalves, paraphyly of protobranchiate bivalves, and monophyly of Autolamellibranchiata, Pteriomorphia, Heteroconchia, Palaeoheterodonta, and Heterodonta s.l., which includes the monophyletic taxon Anomalodesmata. These analyses strongly support the conclusion that Anomalodesmata should not receive a class status, and that the heterodont orders Myoida and Veneroida are not monophyletic. Among the most stable results of the analysis are the monophyly of Palaeoheterodonta, grouping the extant trigoniids with the freshwater unionids, and the sister-group relationship of the heterodont families Astartidae and Carditidae, which together constitute the sister taxon to the remaining heterodont bivalves. Internal relationships of the main bivalve groups are discussed on the basis of node support and clade stability. [source] Evidence from a protein-coding gene that acanthocephalans are rotifersINVERTEBRATE BIOLOGY, Issue 1 2000David B. Mark Welch Abstract. Rotifera and Acanthocephala are generally regarded as separate phyla sharing a basal position among triploblast protostomes. This paper presents the first molecular phylogenetic examination of the relationship of Acanthocephala to all three rotifer classes, Seisonidea, Monogononta, and Bdelloidea. Inclusion of Acanthocephala within Rotifera, probably as a sister-taxon to a clade composed of Bdelloidea and Monogononta (the Eurotatoria), is strongly supported by both parsimony and distance methods, using a region of the nuclear coding gene hsp82. Previous molecular evidence for the inclusion of Acanthocephala in the Rotifera suggested that Acanthocephala is a sister-taxon of Bdelloidea, forming the clade Lemniscea. No support is found for this clade, and evidence is presented that the monogonont rotifer used in those analyses, Brachionus plicatilis, may be evolving in an anomalous manner. [source] Molecular fingerprinting evidence of the contribution of wildlife vectors in the maintenance of Salmonella Enteritidis infection in layer farmsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2003E. Liebana Abstract Aims: To provide molecular fingerprinting evidence of the contribution of wildlife vectors in the on-farm epidemiology of Salmonella Enteritidis infections. Methods and Results:Salmonella Enteritidis strains were isolated from wildlife and from farm environment samples collected in 10 egg layer farms. Isolates were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis and PstI,SphI ribotyping. In all 10 farms we were able to identify the same S. Enteritidis clones in wildlife vectors and farm environment. On several occasions the same clones were found before and after cleansing and disinfecting the farm premises. Also in some instances the same clones were present in mice samples, egg contents and spent hens. Conclusions: Definitive molecular evidence for the involvement of several wildlife species (mice, rats, flies, litter beetles and foxes) in the maintenance of S. Enteritidis infection on farms has been presented. Failures in biosecurity seriously compromise the control of this pathogen on laying farms. Significance and Impact of the Study: This paper reports on the use of molecular tools for the study of the epidemiology of S. Enteritidis. It gives useful information to be considered in control programmes for this organism on poultry farms. [source] Genetic structure of Hypochaeris uniflora (Asteraceae) suggests vicariance in the Carpathians and rapid post-glacial colonization of the Alps from an eastern Alpine refugiumJOURNAL OF BIOGEOGRAPHY, Issue 12 2007Patrik Mráz Abstract Aim, The range of the subalpine species Hypochaeris uniflora covers the Alps, Carpathians and Sudetes Mountains. Whilst the genetic structure and post-glacial history of many high-mountain plant taxa of the Alps is relatively well documented, the Carpathian populations have often been neglected in phylogeographical studies. The aim of the present study is to compare the genetic variation of the species in two major European mountain systems , the Alps and the Carpathians. Location, Alps and Carpathians. Methods, The genetic variation of 77 populations, each consisting of three plants, was studied using amplified fragment length polymorphism (AFLP). Results, Neighbour joining and principal coordinate analyses revealed three well-supported phylogeographical groups of populations corresponding to three disjunct geographical regions , the Alps and the western and south-eastern Carpathians. Moreover, two further clusters could be distinguished within the latter mountain range, one consisting of populations from the eastern Carpathians and the second consisting of populations from the southern Carpathians. Populations from the Apuseni Mountains had an intermediate position between the eastern and southern Carpathians. The genetic clustering of populations into four groups was also supported by an analysis of molecular variance, which showed that most genetic variation (almost 46%) was found among these four groups. By far the highest within-population variation was found in the eastern Carpathians, followed by populations from the southern and western Carpathians. Generally, the populations from the Alps were considerably less variable and displayed substantially fewer region-diagnostic markers than those from the south-eastern Carpathians. Although no clear geographical structure was found within the Alps, based on neighbour joining or principal coordinate analyses, some trends were obvious: populations from the easternmost part were genetically more variable and, together with those from the south-western part, exhibited a higher proportion of rare AFLP fragments than populations in other areas. Moreover, the total number of AFLP fragments per population, the percentage of polymorphic loci and the proportion of rare AFLP fragments significantly decreased from east to west. Main conclusions, Deep infraspecific phylogeographical gaps between the populations from the Alps and the western and south-eastern Carpathians suggest the survival of H. uniflora in three separate refugia during the last glaciation. Our AFLP data provide molecular evidence for a long-term geographical disjunction between the eastern and western Carpathians, previously suggested from the floristic composition at the end of 19th century. It is likely that Alpine populations survived the Last Glacial in the eastern part of the Alps, from where they rapidly colonized the rest of the Alps after the ice sheet retreated. Multiple founder effects may explain a gradual loss of genetic variation during westward colonization of the Alps. [source] Biogeography and molecular phylogeny of the genus Schizothorax (Teleostei: Cyprinidae) in China inferred from cytochrome b sequencesJOURNAL OF BIOGEOGRAPHY, Issue 8 2006Dekui He Abstract Aim, To test a vicariant speciation hypothesis derived from geological evidence of large-scale changes in drainage patterns in the late Miocene that affected the drainages in the south-eastern Tibetan Plateau. Location, The Tibetan Plateau and adjacent areas. Methods, The cytochrome b DNA sequences of 30 species of the genus Schizothorax from nine different river systems were analysed. These DNA sequences were analysed using parsimony, maximum likelihood and Bayesian methods. The approximately unbiased and Shimodaira,Hasegawa tests were applied to evaluate the statistical significance of the shortest trees relative to alternative hypotheses. Dates of divergences between lineages were estimated using the nonparametric rate smoothing method, and confidence intervals of dates were obtained by parametric bootstrapping. Results, The phylogenetic relationships recovered from molecular data were inconsistent with traditional taxonomy, but apparently reflected geographical associations with rivers. Within the genus Schizothorax, we observed a divergence between the lineages from the Irrawaddy,Lhuit and Tsangpo,Parlung rivers, and tentatively dated this vicariant event back to the late Miocene (7.3,6.8 Ma). We also observed approximately simultaneous geographical splits within drainages of the south-eastern Tibetan Plateau, the Irrawaddy, the Yangtze and the Mekong,Salween rivers in the late Miocene (7.1,6.2 Ma). Main conclusions, Our molecular evidence tentatively highlights the importance of palaeoriver connections and the uplift of the Tibetan Plateau in understanding the evolution of the genus Schizothorax. Molecular estimates of divergence times allowed us to date these vicariant scenarios back to the late Miocene, which agrees with geological suggestions for the separation of these drainages caused by tectonic uplift in south-eastern Tibet. Our results indicated the substantial role of vicariant-based speciation in shaping the current distribution pattern of the genus Schizothorax. [source] Is Diurodrilus an annelid?JOURNAL OF MORPHOLOGY, Issue 12 2008Katrine Worsaae Abstract Interstitial marine meiofaunal worms of the genus Diurodrilus have always been considered part of Annelida, either as basal or derived, though generally with reference to Dinophilidae. New evidence shows that Diurodrilus has a unique anatomy, and lacks key annelid features, possibly even segmentation. We assessed the systematic position of Diurodrilus among other protostome animals via light microscopy, confocal laser scanning microscopy, and transmission electron microscopy studies of anatomy, focusing on musculature, the nervous system, as well as molecular sequence data. We show that there is little morphological or molecular evidence to support a relationship with Dinophilidae or any other annelids. Diurodrilus has some similarities to Micrognathozoa, though the latter shows complex jaws. On the basis of the configuration of the nervous system and the cuticle we regard Diurodrilus to belong to Spiralia, possibly close to Annelida; however, until further evidence is acquired it should be regarded as incertae sedis in this large animal clade. J. Morphol., 2008. © 2008 Wiley-Liss, Inc. [source] Differences in multidrug resistance phenotype and matrix metalloproteinases activity between endothelial cells from normal brain and gliomaJOURNAL OF NEUROCHEMISTRY, Issue 2 2003Anthony Régina Abstract Endothelial cells (ECs) are new targets for tumor therapy. In this work, we purified endothelial cells from intracerebral and subcutaneous experimental gliomas as well as from normal brain in order to define some of the phenotypical differences between angiogenic and quiescent brain vasculature. We show that the multidrug resistance genes encoding drug efflux pumps at the brain endothelium are expressed differently in normal and tumoral vasculature. We also show that ECs from gliomas present increased activity of gelatinase B (MMP9), key enzyme in the angiogenic process. Importantly, we observe a different phenotype between ECs in the intracerebral and subcutaneous models. Our results provide molecular evidence of phenotypic distinction between tumoral and normal brain vasculature and indicate that the EC phenotype depends on interactions both with tumor cells and also with the microenvironment. [source] | ||||||||||||||||||||||||||||||||||