Eurotatorian paraphyly: Revisiting phylogenetic relationships based on the complete mitochondrial genome sequence of Rotaria rotatoria (Bdelloidea: Rotifera: Syndermata)

<p>Abstract</p> <p>Background</p> <p>The Syndermata (Rotifera+Acanthocephala) is one of the best model systems for studying the evolutionary origins and persistence of different life styles because it contains a series of lineage-specific life histories: Monogononta (cyclic parthenogenetic and free-living), Bdelloidea (entirely parthenogenetic and mostly benthic dweller), Seisonidea (exclusively bisexual and epizoic or ectoparasitic), and Acanthocephala (sexual and obligatory endoparasitic). Providing phylogenetic resolution to the question of Eurotatoria (Monogononta and Bdelloidea) monophyly versus paraphyly is a key factor for better understanding the evolution of different life styles, yet this matter is not clearly resolved. In this study, we revisited this issue based on comparative analysis of complete mitochondrial genome information for major groups of the Syndermata.</p> <p>Results</p> <p>We determined the first complete mitochondrial genome sequences (15,319 bp) of a bdelloid rotifer, <it>Rotaria rotatoria</it>. In order to examine the validity of Eurotatoria (Monogononta and Bdelloidea) monophyly/paraphyly, we performed phylogenetic analysis of amino acid sequences for eleven protein-coding genes sampled from a wide variety of bilaterian representatives. The resulting mitochondrial genome trees, inferred using different algorithms, consistently failed to recover Monogononta and Bdelloidea as monophyletic, but instead identified them as a paraphyletic assemblage. Bdelloidea (as represented by <it>R. rotatoria</it>) shares most common ancestry with Acanthocephala (as represented by <it>L. thecatus</it>) rather than with monogonont <it>B. plicatilis</it>, the other representative of Eurotatoria.</p> <p>Conclusion</p> <p>Comparisons of inferred amino acid sequence and gene arrangement patterns with those of other metazoan mtDNAs (including those of acanthocephalan <it>L. thecatus </it>and monogonont <it>B. plicatilis</it>) support the hypothesis that Bdelloidea shares most common ancestry with Acanthocephala rather than with Monogononta. From this finding, we suggest that the obligatory asexuality of bdelloideans may have secondarily derived from some other preexisting condition in earlier lineage of rotifers. Providing a more complete assessment of phylogenetic relationships and inferring patterns of evolution of different types of life styles among Syndermata awaits comparisons requiring mitochondrial genome sequencing of Seisonidea.</p

Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant

We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology supernova remnant shows a clumpy distribution, and the line intensity is nearly constant with radius. The C III 977 line, though too weak to be mapped over the whole remnant, is shown to vary radially. The line intensity peaks at about half the radius, and drops at the edge of the remnant. Both the clumpy distribution of C IV and the rise in the C IV to C III ratio towards the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.Comment: 9 pages, 4 figures, will be published in ApJ December 1, 2007, v670n2 issue. see http://astro.snu.ac.kr/~jhshinn/ms.pd

Laparoscopic reversal of Hartmann's procedure

Reversal of Hartmann's procedure is a major surgical procedure associated with significant morbidity and mortality. Because of the difficulty of the procedure, laparoscopic reversal of Hartmann's procedure is not well established. We describe our experience with this laparoscopic procedure to assess its difficulty and safety. Five patients (4 men and 1 woman) underwent laparoscopic reversal of Hartmann's procedure (LRHP). The initial surgeries were performed to manage obstructive colorectal cancer for 4 patients, and rectovesical fistula for one patient. The procedure was laparoscopically completed for 4 patients. Conversion to open laparotomy was required for one patient, secondary to massive adhesion in lower abdomen. Transient ileostomies were made in 2 cases. Operative time ranged from 240 to 545 minutes. There was no operative mortality. LRHP can be performed safely by an experienced surgeon. However, it is still technically challenging and time consuming

Audiologic Patterns of Otic Capsule Preserving Temporal Bone Fracture: Effects of the Affected Subsites

Objectives. This study was aimed to assess the relationship between the type of temporal bone area involved and conductive hearing loss. Methods. We enrolled 97 patients who visited the otolaryngology clinics of Seoul National University Hospital or Boramae Medical Center, Seoul Metropolitan Government-Seoul National University with temporal bone fracture between January 2004 and January 2014. Audiometric parameters, including initial and improved air-bone (AB) conduction gap values, were reviewed in accordance with the temporal bone computed tomography (external auditory canal [EAC], middle ear [ME], mastoid [M], and ossicle [O]). Results. Patients with ossicular chain involvement exhibited a larger AB gap compared to those with no ossicular chain involvement at 250, 1,000, 2,000, and 4,000 Hz. Among the groups without ossicular chain involvement, the initial AB gap was largest in patients with EAC+ME+M involvement, followed by the ME+M and M-only involvement groups. The greatest improvement in the AB gap was observed in the EAC+ME+M group followed by the ME+M and M-only groups, irrespective of ossicular chain involvement. Improvements in AB gap values were smallest at 2,000 Hz. Conclusion. Conductive hearing loss pattern differed according to the temporal bone area involved. Therefore, areas such as the hematoma and hemotympanum, as well as the fracture line of the temporal bone area, must be evaluated to predict audiologic patterns with otic capsule preserving temporal bone fracture