Culex pipiens L., the northern house mosquito, is the primary vector of West Nile virus to humans along the east coast of North America and thus the focus of much study. This species is an urban container-breeding mosquito whose close contact with humans and flexibility in host choice has led to its classification as a "bridge vector"; that is, it is thought to move zoonotic diseases to humans from vertebrate reservoirs. While this invasive species is now well documented in its established range, which expanded in 2001 to include Canada, the existence of populations of this species along the fringes of its range are less well known. Here we report, using morphological and genetic techniques, the existence of two locations where Cx. pipiens exists in Newfoundland in both expected and unexpected sites based on projected habitat suitability on the island.
We report the results of biochemical and molecular investigations on a group of patients from the Saguenay-Lac-Saint-Jean region of Quebec who have an unusual form of cytochrome oxidase deficiency and Leigh disease. This group can be distinguished from the classical presentation of cytochrome oxidase deficiency with Leigh disease, by the severity of the biochemical defect in different tissues. The activity in skin fibroblasts, amniocytes, and skeletal muscle of cytochrome oxidase is 50% of normal, while in kidney and heart it is close to normal values. Brain and liver, on the other hand, have very low activities. The defect in activity appears to result from a failure of assembly of the cytochrome oxidase complex in liver, but levels of mRNA for both mitochondrially encoded and nuclear-encoded subunits in liver and skin fibroblasts were found to be the same as those in controls. The cDNA sequence of the liver-specific cytochrome oxidase subunits VIa and VIIa were determined in samples from patient liver and skin fibroblasts and showed normal coding sequence.
Brief communication: mitochondrial DNA variation suggests extensive gene flow from Polynesian ancestors to indigenous Melanesians in the northwestern Bismarck Archipelago.
Archaeological, linguistic, and genetic studies show that Austronesian (AN)-speaking Polynesian ancestors came from Asia/Taiwan to the Bismarck Archipelago in Near Oceania more than 3,600 years ago, and then expanded into Remote Oceania. However, it remains unclear whether they extensively mixed with indigenous Melanesians who had populated the Bismarck Archipelago before their arrival. To examine the extent of admixture between Polynesian ancestors and indigenous Melanesians, mitochondrial DNA (mtDNA) variations in the D-loop region and the cytochrome oxidase and lysine transfer RNA (COII/tRNA(Lys)) intergenic 9-bp deletion were analyzed in the following three Oceanian populations: 1) Balopa Islanders as AN-speaking Melanesians living in the northwestern end of the Bismarck Archipelago, 2) Tongans as AN-speaking Polynesians, and 3) Gidra as non-Austronesian-speaking Melanesians in the southwestern lowlands of Papua New Guinea. Phylogenetic analysis of mtDNA sequences revealed that more than 60% of mtDNA sequences in the Balopa Islanders were very similar to those in Tongans, suggesting an extensive gene flow from Polynesian ancestors to indigenous Melanesians. Furthermore, analysis of pairwise difference distributions for the D-loop sequences with the 9-bp deletion and the Polynesian motif (i.e., T16217C, A16247G, and C16261T) suggested that the expansion of Polynesian ancestors possessing these variations occurred approximately 7,000 years ago.
Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia; Laboratory of Parasitic Worms and Protistology, Zoological Institute RAS, Universitetskaya nab. 1, 199034 St. Petersburg, Russia. Electronic address: alexander.kudryavtsev@spbu.ru.
We isolated and described a brackish-water amoeba, Clydonella sawyeri n. sp. (Amoebozoa, Vannellida), from the littoral habitat in Kandalaksha Bay (The White Sea, northwestern Russia). Morphology of this amoeba corresponds to the initially proposed diagnosis of the genus Clydonella Sawyer, 1975, although it is sufficiently different from other described species of this genus to warrant a distinct species designation. Phylogenetic analysis based on the small-subunit rRNA gene shows that this species is closely related to the two previously studied ATCC strains identified as Clydonella sp., for which only ultrastructural and molecular data were published. Cytochrome oxidase subunit 1 (COI) gene sequence of the studied species was for the first time obtained for Clydonella. Analysis of this marker shows that this genus belongs to Vannellida and is separated from the other vannellids sampled to date. Phylogenetic analysis of the concatenated SSU rRNA and COI genes dataset yields the best resolved position of Clydonella compared to both markers when analysed separately. Based on the data presented we finally link light microscopic, ultrastructural and molecular data in a description of a single strain, which allows a refinement of the diagnosis of the genus Clydonella.
There is substantial evidence that mitochondrial dysfunction is linked to insulin resistance and is present in several tissues relevant to the pathogenesis of type 2 diabetes. Here, we examined whether common variation in genes involved in oxidative phosphorylation (OxPhos) contributes to type 2 diabetes susceptibility or influences diabetes-related metabolic traits.
OxPhos gene variants (n = 10) that had been nominally associated (p
DNA barcoding is a practical tool for species identification, when morphological classification of an organism is difficult. Herein we describe the utilisation of this technique in a case of ophthalmomyiasis interna. A 12-year-old boy was infested during a summer holiday in northern Norway, while visiting an area populated with reindeer. Following medical examination, a Diptera larva was surgically removed from the boy's eye and tentatively identified from its morphological traits as Hypoderma tarandi (L.) (Diptera: Oestridae). Ultimately, DNA barcoding confirmed this impression. The larval cytochrome c oxidase subunit 1 (COI) DNA sequence was matched with both profiles of five adult H. tarandi from the same region where the boy was infested, and other established profiles of H. tarandi in the Barcode of Life Data Systems (BOLD) identification engine.
Development and application of real-time PCR for specific detection of Lepeophtheirus salmonis and Caligus elongatus larvae in Scottish plankton samples.
Lepeophtheirus salmonis and Caligus elongatus are important parasites of wild and cultured salmonids in the Northern Hemisphere. These species, generically referred to as sea lice, are estimated to cost the Scottish aquaculture industry in excess of pound 25 million per annum. There is great interest in countries such as Ireland, Scotland, Norway and Canada to sample sea lice larvae in their natural environment in order to understand lice larvae distribution and improve parasite control. Microscopy is currently relied on for use in the routine identification of sea lice larvae in plankton samples. This method is, however, limited by its time-consuming nature and requirement for highly skilled personnel. The development of alternative methods for the detection of sea lice larvae which might be used to complement and support microscopic examinations of environmental samples is thus desirable. In this study, a genetic method utilising a real-time PCR Taqman-MGB probe-based assay targeting the mitochondrial cytochrome oxidase I (mtCOI) gene was developed, which allowed species-specific detection of L. salmonis and C. elongatus larvae from unsorted natural and spiked plankton samples. Real-time PCR is a rapid, sensitive, highly specific and potentially quantitative technique. This study demonstrated its suitability for the routine identification of L. salmonis and C. elongatus in mixed plankton samples. The real-time PCR assay developed has considerable potential for use in complementing, supporting and reducing reliance on time-consuming conventional microscopic examination for the specific identification of sea lice larvae in plankton samples.
Feather mites (Astigmata: Analgoidea and Pterolichoidea) are among the most abundant and commonly occurring bird ectosymbionts. Basic questions on the ecology and evolution of feather mites remain unanswered because feather mite species identification is often only possible for adult males, and it is laborious even for specialized taxonomists, thus precluding large-scale identifications. Here, we tested DNA barcoding as a useful molecular tool to identify feather mites from passerine birds. Three hundred and sixty-one specimens of 72 species of feather mites from 68 species of European passerine birds from Russia and Spain were barcoded. The accuracy of barcoding and minibarcoding was tested. Moreover, threshold choice (a controversial issue in barcoding studies) was also explored in a new way, by calculating through simulations the effect of sampling effort (in species number and species composition) on threshold calculations. We found one 200-bp minibarcode region that showed the same accuracy as the full-length barcode (602 bp) and was surrounded by conserved regions potentially useful for group-specific degenerate primers. Species identification accuracy was perfect (100%) but decreased when singletons or species of the Proctophyllodes pinnatus group were included. In fact, barcoding confirmed previous taxonomic issues within the P. pinnatus group. Following an integrative taxonomy approach, we compared our barcode study with previous taxonomic knowledge on feather mites, discovering three new putative cryptic species and validating three previous morphologically different (but still undescribed) new species.
The Ã?strand Laboratory of Work Physiology, GIH, The Swedish School of Sport and Health Sciences, Box 5626, 114 86 Stockholm, Sweden. niklas.psilander@gih.se
Recent studies suggest that carbohydrate restriction can improve the training-induced adaptation of muscle oxidative capacity. However, the importance of low muscle glycogen on the molecular signaling of mitochondrial biogenesis remains unclear. Here, we compare the effects of exercise with low (LG) and normal (NG) glycogen on different molecular factors involved in the regulation of mitochondrial biogenesis. Ten highly trained cyclists (VO(2max) 65 ± 1 ml/kg/min, W max 387 ± 8 W) exercised for 60 min at approximately 64 % VO(2max) with either low [166 ± 21 mmol/kg dry weight (dw)] or normal (478 ± 33 mmol/kg dw) muscle glycogen levels achieved by prior exercise/diet intervention. Muscle biopsies were taken before, and 3 h after, exercise. The mRNA of peroxisome proliferator-activated receptor-? coactivator-1 was enhanced to a greater extent when exercise was performed with low compared with normal glycogen levels (8.1-fold vs. 2.5-fold increase). Cytochrome c oxidase subunit I and pyruvate dehydrogenase kinase isozyme 4 mRNA were increased after LG (1.3- and 114-fold increase, respectively), but not after NG. Phosphorylation of AMP-activated protein kinase, p38 mitogen-activated protein kinases and acetyl-CoA carboxylase was not changed 3 h post-exercise. Mitochondrial reactive oxygen species production and glutathione oxidative status tended to be reduced 3 h post-exercise. We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity.
The external morphological, X-ray, and tomographic study of a frozen rodent mummy from the Upper Pleistocene Yedoma deposits on the Tirekhtyakh River (a Semyuelyakh River tributary, Abyi ulus, Republic of Sakha (Yakutia), Russia) showed its belonging to Lemmus sp. The radiocarbon age of the finding is 41 305-41 885 cal B.P. This is the first Pleistocene discovery of a frozen mummy of a genus Lemmus representative. In terms of the body and skull sizes, coat color, the lower incisor length, and the molar structure, the specimen studied is similar to the recent Lemmus sibiricus (Kerr, 1792). Comparison of the mitochondrial COB gene sequence with the DNA sequences presented in the GenBank database also testified to the maximum similarity with the Recent Siberian brown lemming.
