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Bdelloid rotifer

Christopher G Wilson, Reuben W Nowell, Timothy G Barraclough
A few metazoan lineages are thought to have persisted for millions of years without sexual reproduction. If so, they would offer important clues to the evolutionary paradox of sex itself [1, 2]. Most "ancient asexuals" are subject to ongoing doubt because extant populations continue to invest in males [3-9]. However, males are famously unknown in bdelloid rotifers, a class of microscopic invertebrates comprising hundreds of species [10-12]. Bdelloid genomes have acquired an unusually high proportion of genes from non-metazoans via horizontal transfer [13-17]...
August 6, 2018: Current Biology: CB
Fernando Rodriguez, Irina R Arkhipova
Polyploidy in animals is much less common than in plants, where it is thought to be pervasive in all higher plant lineages. Recent studies have highlighted the impact of polyploidization and the associated process of diploidy restoration on the evolution and speciation of selected taxonomic groups in the animal kingdom: from vertebrates represented by salmonid fishes and African clawed frogs to invertebrates represented by parasitic root-knot nematodes and bdelloid rotifers. In this review, we focus on the unique and diverse roles that transposable elements may play in these processes, from marking and diversifying subgenome-specific chromosome sets before hybridization, to influencing genome restructuring during rediploidization, to affecting subgenome-specific regulatory evolution, and occasionally providing opportunities for domestication and gene amplification to restore and improve functionality...
April 2018: Current Opinion in Genetics & Development
Stephen Richards
Two recent papers highlight the fascinating comparative genomics of anhydrobiosis, the ability to withstand complete desiccation, in bdelloid rotifers and tardigrades. However, both groups had to openly deal with the significant difficulties of generating and interpreting short-read draft assemblies-especially challenging in microscopic species with high sequence polymorphism. These exemplars demonstrate the need to go beyond single draft-quality reference genomes to high-quality multiple species comparative genomics if we are to fully capture the value of genomics...
April 2018: PLoS Biology
Reuben W Nowell, Pedro Almeida, Christopher G Wilson, Thomas P Smith, Diego Fontaneto, Alastair Crisp, Gos Micklem, Alan Tunnacliffe, Chiara Boschetti, Timothy G Barraclough
Bdelloid rotifers are a class of microscopic invertebrates that have existed for millions of years apparently without sex or meiosis. They inhabit a variety of temporary and permanent freshwater habitats globally, and many species are remarkably tolerant of desiccation. Bdelloids offer an opportunity to better understand the evolution of sex and recombination, but previous work has emphasised desiccation as the cause of several unusual genomic features in this group. Here, we present high-quality whole-genome sequences of 3 bdelloid species: Rotaria macrura and R...
April 2018: PLoS Biology
Hiroko Nakayama, Kan Katayama, Yukimasa Onabe, Atsushi Sato, Norihio Nishimura, Yasuhito Shimada
Rotifers are now becoming a standard live feed for first-feeding larvae, because of their easy rearing protocol and improved growth and survival rate, compared with other fish feed, paramecia, and processed powder fish feeds. In a group of rotifers, bdelloid rotifer, a freshwater plankton, exerts cryptobiosis (an ametabolic state of life) in response to desiccation and survived for a long time. Here, we created "dried rotifer sheet" for rearing larvae in their early developmental stage. More than 80% rotifers could survive after 18-month desiccation in the filter paper...
June 2018: Zebrafish
Zsolt Datki, Zita Olah, Tibor Hortobagyi, Lilla Macsai, Katalin Zsuga, Livia Fulop, Zsolt Bozso, Bence Galik, Eva Acs, Angela Foldi, Amanda Szarvas, Janos Kalman
Neurodegenerative diseases are linked to a systemic enzyme resistance of toxic aggregated molecules and their pathological consequences. This paper presents a unique phenomenon that Philodina acuticornis, a bdelloid rotifer, is able to catabolize different types of neurotoxic peptide and protein aggregates (such as beta-amyloids /Aβ/, alpha-synuclein, and prion) without suffering any damage. P. acuticornis is capable of using these aggregates as an exclusive energy source (i.e., as 'food', identified in the digestive system and body) in a hermetically isolated microdrop environment, increasing their survival...
January 29, 2018: Acta Neuropathologica Communications
Yuki Yoshida, Georgios Koutsovoulos, Dominik R Laetsch, Lewis Stevens, Sujai Kumar, Daiki D Horikawa, Kyoko Ishino, Shiori Komine, Takekazu Kunieda, Masaru Tomita, Mark Blaxter, Kazuharu Arakawa
Tardigrada, a phylum of meiofaunal organisms, have been at the center of discussions of the evolution of Metazoa, the biology of survival in extreme environments, and the role of horizontal gene transfer in animal evolution. Tardigrada are placed as sisters to Arthropoda and Onychophora (velvet worms) in the superphylum Panarthropoda by morphological analyses, but many molecular phylogenies fail to recover this relationship. This tension between molecular and morphological understanding may be very revealing of the mode and patterns of evolution of major groups...
July 2017: PLoS Biology
Terry W Snell, Rachel K Johnston, Amelia B Matthews
Rotifers have become widely used in aquatic toxicology as a rapid screening test for toxicity. The commercial availability of diapausing embryos (cysts) have facilitated their popularity because test animals can be obtained without having to master the details of culturing. Other rotifer species have life stages capable of surviving desiccation and also could be used in non-culture systems for toxicity assessment. In this article, we describe a system for toxicity testing in freshwater based on rehydrating desiccated bdelloid rotifers in the genus Philodina...
October 2017: Environmental Toxicology
Min Ok Song, Chang-Ho Lee
A taxonomic study on bdelloid rotifers collected from various terrestrial habitats at six different locations in Korea yielded 12 new Korean records and a new species, Philodina koreana n. sp. Among the 12 new Korean records, eight species and two subspecies are new to Asia. These new Asian records include five rare species with poorly known distributions. Philodina childi Milne and P. scabra Milne were rediscovered in Korea almost 100 years after the original descriptions from South Africa. Our study is the first to report Habrotrocha longicalcarata Bērzinš outside its type locality...
March 13, 2017: Zootaxa
Zita Olah, Ashley I Bush, David Aleksza, Bence Galik, Eszter Ivitz, Lilla Macsai, Zoltan Janka, Zoltan Karman, Janos Kalman, Zsolt Datki
Rotifers have been used in biological research as well-characterized models of aging. Their multi-organ characters and their sensitivity for chemicals and environmental changes make them useful as in vivo toxicological and lifespan models. Our aim was to create a bdelloid rotifer model to use in high-throughput viability and non-invasive assays. In order to identify our species Philodina acuticornis odiosa (PA), 18S rDNA-based phylogenetic analysis was carried out and their species-specific morphological markers identified...
October 2017: Ecotoxicology and Environmental Safety
Fernando Rodriguez, Aubrey W Kenefick, Irina R Arkhipova
Rotifers of the class Bdelloidea, microscopic freshwater invertebrates, possess a highlydiversified repertoire of transposon families, which, however, occupy less than 4% of genomic DNA in the sequenced representative Adineta vaga . We performed a comprehensive analysis of A. vaga retroelements, and found that bdelloid long terminal repeat (LTR)retrotransposons, in addition to conserved open reading frame (ORF) 1 and ORF2 corresponding to gag and pol genes, code for an unusually high variety of ORF3 sequences...
April 11, 2017: Viruses
Mai Kanazawa, Takahiro Nanri, Masayuki Saigusa
The bdelloid rotifer of the genus Adineta is a freshwater metazoan characterized by anhydrobiosis, a highly stable state of suspended animation induced by desiccation. This study investigated the influence of anhydrobiosis on the thermal habituation by use of an index, Activity Ratio (AR = the number of active rotifers at each experimental temperature/ number of active rotifers at the 25°C stage). In the first experiment, rotifers were divided into two groups: one group was cultivated at 25°C throughout experiment, and another group was transferred to 15°C for two days...
April 2017: Zoological Science
S K Schmidt, J L Darcy, Pacifica Sommers, Eva Gunawan, J E Knelman, Karina Yager
This is the first study of the highest elevation cyanobacteria-dominated microbial mat yet described. The desiccated mat was sampled in 2010 from an ephemeral rock pool at 5500 m above sea level in the Cordillera Vilcanota of southern Perú. After being frozen for 6 years at -20 °C in the lab, pieces of the mat were sequenced to fully characterize both the 16 and 18S microbial communities and experiments were conducted to determine if organisms in the mat could revive and become active under the extreme freeze-thaw conditions that these mats experience in the field...
May 2017: Extremophiles: Life Under Extreme Conditions
K Ingemar Jönsson, Andrzej Wojcik
The aim of this study was to analyze tolerance to heavy ions in desiccated animals of the eutardigrade Richtersius coronifer and the bdelloid rotifer Mniobia russeola within the STARLIFE project. Both species were exposed to iron (Fe) and helium (He) ions at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Chiba, Japan, and to X-rays at the German Aerospace Center (DLR) in Cologne, Germany. Results show no effect of Fe and He on viability up to 7 days post-rehydration in both R. coronifer and M. russeola, while X-rays tended to reduce viability in R...
February 2017: Astrobiology
Guoji Ding, Xiaowei Li, Wei Lin, Yuzuru Kimochi, Ryuichi Sudo
Bdelloid rotifer are reported to play a promoting role in microbial aggregation and floc formation in activated sludge systems; however, the mechanisms involved in this process are unclear. This study explores the effect of a rotifer secretion (RS) from the species Philodina erythrophthalma on the flocculation and growth of two bioflocculation-producing bacteria isolated from activated sludge. Results show that although the secretion has weak bioflocculability in itself, it can significantly enhance the flocculability of bioflocculation-producing bacteria and promote formation of microbial aggregation and floc...
April 1, 2017: Water Research
Olaf R P Bininda-Emonds, Claus Hinz, Wilko H Ahlrichs
Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens), which, like other monogononts, is facultative sexual and cannot withstand desiccation...
September 6, 2016: Life
Elton G G Barbosa, Alastair Crisp, Sarah E Broadbent, Martina Carrillo, Chiara Boschetti, Alan Tunnacliffe
The form of RNA processing known as SL trans-splicing involves the transfer of a short conserved sequence, the spliced leader (SL), from a noncoding SL RNA to the 5' ends of mRNA molecules. SL trans-splicing occurs in several animal taxa, including bdelloid rotifers (Rotifera, Bdelloidea). One striking feature of these aquatic microinvertebrates is the large proportion of foreign genes, i.e. those acquired by horizontal gene transfer from other organisms, in their genomes. However, whether such foreign genes behave similarly to native genes has not been tested in bdelloids or any other animal...
September 15, 2016: Gene
Raquel A Moreira, Adrislaine S Mansano, Odete Rocha
This paper describes experimental results on the life cycle of the rotifer Philodina roseola cultured in the laboratory. Detailed information on life-cycle parameters of a certain species provides a deep understanding and contributes to a better knowledge of the role of the species in the community, besides providing data that are basic to other ecological investigations such as secondary production estimates and knowledge for applications such as its utilization as test-organism in ecotoxicological studies...
2016: Anais da Academia Brasileira de Ciências
Fernando Rodriguez, Irina R Arkhipova
RNA-mediated silencing processes play a key role in silencing of transposable elements, especially in the germ line, where piwi-interacting RNAs (piRNAs) are responsible for suppressing transposon mobility and maintaining genome integrity. We previously reported that the genome of Adineta vaga, the first sequenced representative of the phylum Rotifera (class Bdelloidea), is characterized by massive levels of horizontal gene transfer, by unusually low transposon content, and by highly diversified RNA-mediated silencing machinery...
May 2016: Genetics
Tanja Schwander
Bdelloid rotifers were believed to have persisted and diversified in the absence of sex. Two papers now show they exchange genes with each other, via horizontal gene transfers as known in bacteria and/or via other forms of non-canonical sex.
March 21, 2016: Current Biology: CB
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