The mitochondrial genome of Paragyrodactylus variegatus (Platyhelminthes: Monogenea): differences in major non-coding region and gene order compared to Gyrodactylus

Publisher's Version/PDFBackground: Paragyrodactylus Gvosdev and Martechov, 1953, a viviparous genus of ectoparasite within the Gyrodactylidae, contains three nominal species all of which infect Asian river loaches. The group is suspected to be a basal lineage within Gyrodactylus Nordmann, 1832 sensu lato although this remains unclear. Further molecular study, beyond characterization of the standard Internal Transcribed Spacer region, is needed to clarify the evolutionary relationships within the family and the placement of this genus. Methods: The mitochondrial genome of Paragyrodactylus variegatus You, King, Ye and Cone, 2014 was amplified in six parts from a single worm, sequenced using primer walking, annotated and analyzed using bioinformatic tools. Results: The mitochondrial genome of P. variegatus is 14,517 bp, containing 12 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and a major non-coding region (NCR). The overall A + T content of the mitochondrial genome is 76.3%, which is higher than all reported mitochondrial genomes of monogeneans. All of the 22 tRNAs have the typical cloverleaf secondary structure, except tRNACys, tRNASer1 and tRNASer2 that lack the dihydrouridine (DHU) arm. There are six domains (domain III is absent) and three domains in the inferred secondary structures of the large ribosomal subunit (rrnL) and small ribosomal subunit (rrnS), respectively. The NCR includes six 40 bp tandem repeat units and has the double identical poly-T stretches, stem-loop structure and some surrounding structure elements. The gene order (tRNAGln, tRNAMet and NCR) differs in arrangement compared to the mitochondrial genomes reported from Gyrodactylus spp. Conclusion: The Duplication and Random Loss Model and Recombination Model together are the most plausible explanations for the variation in gene order. Both morphological characters and characteristics of the mitochondrial genome support Paragyrodactylus as a distinct genus from Gyrodactylus. Considering their specific distribution and known hosts, we believe that Paragyrodactylus is a relict freshwater lineage of viviparous monogenean isolated in the high plateaus of central Asia on closely related river loaches

Local patchiness of Gyrodactylus colemanensis and G. salmonis parasitizing salmonids in the South River watershed, Nova Scotia, Canada

Publisher's Version/PDFPrevalence and intensity of Gyrodactylus colemanensis and G. salmonis (Monogenea) parasitizing juvenile/adult brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, brown trout Salmo trutta, and Atlantic salmon Salmo salar at 3 localities over an 8 km stretch in the South River, Nova Scotia, Canada, were calculated 4 times over a 9 mo period (October 2009, December 2009, March 2010, June 2010). G. colemanensis was on all 4 salmonids (endemic and non-endemic), while G. salmonis parasitized mostly S. fontinalis (endemic) and occasionally S. trutta (non-endemic). At an upstream locality, beyond a waterfall barrier, in a small tributary of the main river, G. colemanensis was more common than G. salmonis. In the main river, 7 km downstream, prevalence of G. colemanensis on S. fontinalis was comparable, or higher, than that of G. salmonis, while intensity of G. salmonis was higher than that of G. colemanensis. Downstream a further 1 km, in a tributary of the main river, both prevalence and intensity of G. salmonis on brook trout were higher than those of G. colemanensis. Stocks at a local trout hatchery had only G. colemanensis. The present study reports on a method by which exit water from such farms can be monitored for gyrodactylid parasites through a simple settling procedure. We estimated that up to 230 000 dislodged, live G. colemanensis exit the hatchery daily in discharge water entering the river. It is suggested that such systems are ideal for studying the impact of such parasite export on the nature of local parasite populations

Differences between SALLJ and No SALLJ events and its impact on the development of mesoscale convective systems over subtropical South America

Prior studies have shown that a low-level jet is a recurrent characteristic of the environment during the initiation and maturing of mesoscale convective systems (MCS) in the Great Plains of the United States. The South American low-level jet (SALLJ) has an analogous role, advecting heat and moisture from the Amazon basin southward into the central plains of southeastern South America (SESA), generating ideal environmental conditions for convection initiation and growth into MCSs. High frequency of MCSs is evident in the subtropical area under conditions SALLJ, but during situations without SALLJ the presence of organized convection is still significant in this region. The purpose of this research is to describe the environment associated with the subtropical MCSs over SESA and their strong relationship to the SALLJ. The differences between the environment associated to MCS during days without SALLJ are studied in order to advance in the knowledge of the conditions that precede the MCS development. IR satellite images with high temporal and horizontal resolution are used to detect large subtropical MCSs during the period 2000-2003. A definition of MCS similar to that used by Cotton et al. (1989) and by Nicolini et al. (2002) is applied in order to study deep and organized convection in a sample of systems with features similar to those studied by other authors in different parts of the world. The initiation stage of the systems is defined when the area enclosed by the -55 \ub0C (218 \ub0K) isotherm exceeds 50,000 km² (3,125 pixels). The mature stage is attained when the above area reaches its maximum extent, whereas the dissipation stage is defined when the enclosed area again crosses the 50,000 km² threshold. The environment associated with the systems is described using operational analyses (GDAS - Global Data Assimilation System) with high spatial and 6-hours temporal resolution. SALLJ and No SALLJ days are detected using GDAS, a criteria similar to Bonner (1968) is used to identify this events. . During the 3-year period 645 MCSs were detected satisfying the MCS criteria. These systems are distributed during the seasons studied as follows: 286 in summer, 202 in spring and 157 in the fall. Systems which achieve their maximum extent north of 23\ub0S were considered as tropical, and the remainder as subtropical. Subtropical systems represent 33.2 per cent of the sample, the tropical systems 66.8 per cent. During spring, summer and fall at least one subtropical MCS developed in 41 per cent of the SALLJ days, whereas in the days without SALLJ this percentage dropped to 12 per cent. The environment associated with the large subtropical MCSs exhibits a strong SALLJ during the previous day, and persisting during the whole life cycle of the system. The dissipation stage of the MCS is influenced by the advance of a baroclinic zone that moves towards the north. The percentage of subtropical MCS (35%) that develop under No SALLJ conditions present smaller size and shorter life spam, and the position at the maximum extent time is closer to the Andes..Pages: 1163-117