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https://www.readbyqxmd.com/read/28087777/genome-sequencing-reveals-the-origin-of-the-allotetraploid-arabidopsis-suecica
#1
Polina Yu Novikova, Takashi Tsuchimatsu, Samson Simon, Viktoria Nizhynska, Viktor Voronin, Robin Burns, Olga M Fedorenko, Svante Holm, Torbjörn Säll, Elisa Prat, William Marande, Vincent Castric, Magnus Nordborg
Polyploidy is an example of instantaneous speciation when it involves the formation of a new cytotype that is incompatible with the parental species. Because new polyploid individuals are likely to be rare, establishment of a new species is unlikely unless polyploids are able to reproduce through self-fertilization (selfing), or asexually. Conversely, selfing (or asexuality) makes it possible for polyploid species to originate from a single individual - a bona fide speciation event. The extent to which this happens is not known...
January 12, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28087686/amoebozoans-are-secretly-but-ancestrally-sexual-evidence-for-sex-genes-and-potential-novel-crossover-pathways-in-diverse-groups-of-amoebae
#2
Yonas I Tekle, Fiona C Wood, Laura A Katz, Mario A Cerón-Romero, Lydia A Gorfu
Sex is beneficial in eukaryotes as it can increase genetic diversity, reshuffle their genomes, and purge deleterious mutations. Yet, its evolution remains a mystery. The eukaryotic clade supergroup Amoebozoa encompasses diverse lineages of polymorphic amoeboid forms, including both free-living and parasitic lineages. The group is generally believed to be asexual, though recent studies show that some of its members are implicated in cryptic forms of sexual cycles. In this study we conduct a comprehensive inventory and analysis of genes involved in meiosis and related processes, in order to investigate the evolutionary history of sex in the clade...
January 13, 2017: Genome Biology and Evolution
https://www.readbyqxmd.com/read/28081440/a-knockout-screen-of-apiap2-genes-reveals-networks-of-interacting-transcriptional-regulators-controlling-the-plasmodium-life-cycle
#3
Katarzyna Modrzynska, Claudia Pfander, Lia Chappell, Lu Yu, Catherine Suarez, Kirsten Dundas, Ana Rita Gomes, David Goulding, Julian C Rayner, Jyoti Choudhary, Oliver Billker
A family of apicomplexa-specific proteins containing AP2 DNA-binding domains (ApiAP2s) was identified in malaria parasites. This family includes sequence-specific transcription factors that are key regulators of development. However, functions for the majority of ApiAP2 genes remain unknown. Here, a systematic knockout screen in Plasmodium berghei identified ten ApiAP2 genes that were essential for mosquito transmission: four were critical for the formation of infectious ookinetes, and three were required for sporogony...
January 11, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28080063/optimization-of-2-anilino-4-amino-substituted-quinazolines-into-potent-antimalarial-agents-with-oral-in-vivo-activity
#4
Paul R Gilson, Cyrus Tan, Kate E Jarman, Kym N Lowes, Joan M Curtis, William Nguyen, Adrian E Di Rago, Hayley E Bullen, Boris Prinz, Sandra Duffy, Jonathan B Baell, Craig A Hutton, Helene Jousset Sabroux, Brendan S Crabb, Vicky M Avery, Alan F Cowman, Brad E Sleebs
Novel antimalarial therapeutics that target multiple stages of the parasites lifecycle are urgently required to tackle the emerging problem of resistance with current drugs. Here we describe the optimization of the 2-anilino quinazoline class as antimalarial agents. The class, identified from publicly available antimalarial screening data, was optimized to generate lead compounds that possess potent antimalarial activity against P. falciparum parasites equivalent to the known antimalarials, chloroquine and mefloquine...
January 12, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28078730/a-fern-aintegumenta-gene-mirrors-baby-boom-in-promoting-apogamy-in-ceratopteris-richardii
#5
Linh T Bui, Dzevida Pandzic, Christopher E Youngstrom, Simon Wallace, Erin E Irish, Péter Szövényi, Chi-Lien Cheng
Asexual reproduction is widespread in land plants, including ferns where 10% of all species are obligate asexuals. In these ferns, apogamous sporophytes are generated directly from gametophytes, bypassing fertilization. In the model fern Ceratopteris richardii, a sexual species, apogamy can be induced by culture on high sugar media. BABY BOOM (BBM) genes in angiosperms are known to promote somatic embryogenesis, which like apogamy produce sporophytes without fertilization. Here, a Brassica napus BBM (BnBBM) was used to investigate genetic similarity between apogamy in ferns and somatic embryogenesis in angiosperms...
January 12, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28074843/sexy-males-and-sexless-females-the-origin-of-triploid-apomicts
#6
P Muralidhar, D Haig
Apomixis and polyploidy are closely associated in angiosperms, but the evolutionary reason for this association is unknown. Taraxacum officinale, the common dandelion, exists both as diploid sexuals and triploid apomicts. Here, in the context of T. officinale, we provide a model of the evolution of triploid apomicts from diploid sexuals. We posit an apomictic allele that arrests female meiosis in diploids, so that the plant produces diploid egg cells that can develop without fertilization, but haploid pollen...
January 11, 2017: Heredity
https://www.readbyqxmd.com/read/28070136/new-talaromyces-species-from-indoor-environments-in-china
#7
A J Chen, B D Sun, J Houbraken, J C Frisvad, N Yilmaz, Y G Zhou, R A Samson
Talaromyces contains both asexual and sexually reproducing species. This genus is divided in seven sections and currently has 105 accepted species. In this study we investigated the Talaromyces isolates that were obtained during a study of indoor air collected in Beijing, China. These indoor Talaromyces strains are resolved in four sections, seven of them are identified as T. islandicus, T. aurantiacus, T. siamensis and T. albobiverticillius according to BenA sequences, while 14 isolates have divergent sequences and are described here as nine new species...
June 2016: Studies in Mycology
https://www.readbyqxmd.com/read/28068406/superclone-expansion-long-distance-clonal-dispersal-and-local-genetic-structuring-in-the-coral-pocillopora-damicornis-type-%C3%AE-in-reunion-island-south-western-indian-ocean
#8
Pauline Gélin, Cécile Fauvelot, Vincent Mehn, Sophie Bureau, Héloïse Rouzé, Hélène Magalon
The scleractinian coral Pocillopora damicornis type β is known to present a mixed reproduction mode: through sexual reproduction, new genotypes are created, while asexual reproduction insures their propagation. In order to investigate the relative proportion of each reproduction mode in P. damicornis type β populations from Reunion Island, Indian Ocean, clonal propagation along the west coast was assessed through four sampling sites with increasing geographical distance between sites. Coral colonies were sampled either exhaustively, randomly or haphazardly within each site, and genotypic diversity was assessed using 13 microsatellite loci over a total of 510 P...
2017: PloS One
https://www.readbyqxmd.com/read/28068346/mutation-accumulation-in-an-asexual-relative-of-arabidopsis
#9
John T Lovell, Robert J Williamson, Stephen I Wright, John K McKay, Timothy F Sharbel
Asexual populations experience weaker responses to natural selection, which causes deleterious mutations to accumulate over time. Additionally, stochastic loss of individuals free of deleterious mutations can lead to an irreversible increase in mutational load in asexuals (the "click" in Muller's Ratchet). Here we report on the genomic divergence and distribution of mutations across eight sympatric pairs of sexual and apomictic (asexual) Boechera (Brassicaceae) genotypes. We show that apomicts harbor a greater number of derived mutations than sympatric sexual genotypes...
January 9, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28067475/the-chaperonin-tric-forms-an-oligomeric-complex-in-the-malaria-parasite-cytosol
#10
Natalie J Spillman, Josh R Beck, Suresh M Ganesan, Jacquin C Niles, Daniel E Goldberg
The malaria parasite exports numerous proteins into its host red blood cell (RBC). The trafficking of these exported effectors is complex. Proteins are first routed through the secretory system, into the parasitophorous vacuole (PV), a membranous compartment enclosing the parasite. Proteins are then translocated across the PV membrane in a process requiring ATP and unfolding. Once in the RBC compartment the exported proteins are then refolded and further trafficked to their final localizations. Chaperones are important in the unfolding and refolding processes...
January 9, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/28062360/determination-of-glutathione-redox-potential-and-ph-value-in-subcellular-compartments-of-malaria-parasites
#11
Franziska Mohring, Mahsa Rahbari, Bernd Zechmann, Stefan Rahlfs, Jude M Przyborski, Andreas J Meyer, Katja Becker
The malaria parasite Plasmodium falciparum is exposed to multiple sources of oxidative challenge during its complex life cycle in the Anopheles vector and its human host. In order to further elucidate redox-based parasite host cell interactions and mechanisms of drug action, we targeted the genetically encoded glutathione redox sensor roGFP2 coupled to human glutaredoxin 1 (roGFP2-hGrx1) as well as the ratiometric pH sensor pHluorin to the apicoplast and the mitochondrion of P. falciparum. Using live cell imaging, this allowed for the first time the determination of the pH values of the apicoplast (7...
January 4, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28061382/budding-of-the-alveolate-alga-vitrella-brassicaformis-resembles-sexual-and-asexual-processes-in-apicomplexan-parasites
#12
Zoltán Füssy, Petra Masařová, Jitka Kručinská, Heather J Esson, Miroslav Oborník
Ease of cultivation and availability of genomic data promoted intensive research of free-living phototrophic relatives of apicomplexans, i.e. Chromera velia and Vitrella brassicaformis. Chromera and Vitrella differ significantly in their physiology, morphology, phylogenetic position and genomic features, but Vitrella has not gained as much attention. Here we describe two types of Vitrella zoosporangia. One contains zoospores surrounded by roughly structured matter, with an intracytoplasmic axoneme predicted to develop into a mature flagellum upon spore release, similarly to Plasmodium microgametes; in the second type, cells concurrently bud off the center of the sporangium, surrounded by smooth matter, and flagella develop extracellularly...
December 13, 2016: Protist
https://www.readbyqxmd.com/read/28057829/evolution-of-the-asexual-queen-succession-system-and-its-underlying-mechanisms-in-termites
#13
REVIEW
Kenji Matsuura
One major advantage of sexual reproduction over asexual reproduction is its promotion of genetic variation, although it reduces the genetic contribution to offspring. Queens of social insects double their contribution to the gene pool, while overuse of asexual reproduction may reduce the ability of the colony to adapt to environmental stress because of the loss of genetic diversity. Recent studies have revealed that queens of some termite species can solve this tradeoff by using parthenogenesis to produce the next generation of queens and sexual reproduction to produce other colony members...
January 1, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28057730/insertion-polymorphisms-of-mobile-genetic-elements-in-sexual-and-asexual-populations-of-daphnia-pulex
#14
Xiaoqian Jiang, Haixu Tang, Zhiqiang Ye, Michael Lynch
Transposable elements (TEs) constitute a substantial portion of many eukaryotic genomes, and can in principle contribute to evolutionary innovation as well as genomic deterioration. Daphnia pulex serves as a useful model for studying TE dynamics as a potential cause and/or consequence of asexuality. We analyzed insertion polymorphisms of TEs in 20 sexual and 20 asexual isolates of D. pulex across North American from their available whole-genome sequencing data. Our results show that the total fraction of the derived sequences of TEs is not substantially different between asexual and sexual D...
January 4, 2017: Genome Biology and Evolution
https://www.readbyqxmd.com/read/28057055/functional-characterization-of-plasmodium-berghei-psop25-during-ookinete-development-and-as-a-malaria-transmission-blocking-vaccine-candidate
#15
Wenqi Zheng, Fei Liu, Yiwen He, Qingyang Liu, Gregory B Humphreys, Takafumi Tsuboi, Qi Fan, Enjie Luo, Yaming Cao, Liwang Cui
BACKGROUND: Plasmodium ookinete surface proteins as post-fertilization target antigens are potential malaria transmission-blocking vaccine (TBV) candidates. Putative secreted ookinete protein 25 (PSOP25) is a highly conserved ookinete surface protein, and has been shown to be a promising novel TBV target. Here, we further investigated the TBV activities of the full-length recombinant PSOP25 (rPSOP25) protein in Plasmodium berghei, and characterized the potential functions of PSOP25 during the P...
January 5, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/28055573/guidelines-for-the-detection-of-babesia-and-theileria-parasites
#16
Laetitia Lempereur, Relja Beck, Isabel Fonseca, Cátia Marques, Ana Duarte, Marcos Santos, Sara Zúquete, Jacinto Gomes, Gernot Walder, Ana Domingos, Sandra Antunes, Gad Baneth, Cornelia Silaghi, Patricia Holman, Annetta Zintl
The genera Babesia and Theileria (phylum Apicomplexa, order Piroplasmida) are mainly transmitted by Ixodid ticks in which the sexual part of their life cycle followed by sporogony takes place. They include protozoan parasites that infect erythrocytes of a variety of vertebrate hosts, including domestic and wild animals, with some Babesia spp. also infecting humans. Babesia sporozoites transmitted in the tick's saliva during the bloodmeal directly infect erythrocytes, where they asexually multiply to produce pear-shaped merozoites in the process of merogony; whereas a pre-erythrocytic schizogonic life stage in leukocytes is found in Theileria and precedes merogony in the erythrocytes...
January 2017: Vector Borne and Zoonotic Diseases
https://www.readbyqxmd.com/read/28053272/trans-generational-function-of-tetrahymena-piwi-protein-twi8p-at-distinctive-non-coding-rna-loci
#17
Brian M Farley, Kathleen Collins
Trans-generational transmission of genome-regulatory epigenetic information can determine phenotypes in the progeny of sexual reproduction. Sequence specificity of trans-generational regulation derives from small RNAs assembled into Piwi-protein complexes. Known targets of trans-generational regulation are primarily transposons and transposon-derived sequences. Here, we extend the scope of Piwi-mediated trans-generational regulation to include unique non-coding RNA loci. Ciliates such as Tetrahymena have a phenotypically silent germline micronucleus and an expressed somatic macronucleus, which is differentiated anew from a germline genome copy in sexual reproduction...
January 4, 2017: RNA
https://www.readbyqxmd.com/read/28052996/a-novel-bioengineered-3d-human-intestinal-model-for-long-term-infection-of-cryptosporidium-parvum
#18
Maria A DeCicco RePass, Ying Chen, Yinan Lin, Wenda Zhou, David L Kaplan, Honorine D Ward
Cryptosporidium spp. are apicomplexan parasites of global importance that cause human diarrheal disease. In vitro culture models to study this parasite with physiological relevance to in vivo infection remain sub-optimal. Thus, the pathogenesis of cryptosporidiosis remains poorly characterized, and interventions for the disease are limited. In this study, we evaluated the potential of a novel bioengineered 3D human intestinal tissue model (which we developed previously) to support long term infection by C. parvum...
January 4, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28050233/signaling-transcript-profile-of-the-asexual-intraerythrocytic-development-cycle-of-plasmodium-falciparum-induced-by-melatonin-and-camp
#19
Wânia Rezende Lima, Giulliana Tessarin-Almeida, Andrei Rozanski, Kleber S Parreira, Miriam S Moraes, David C Martins, Ronaldo F Hashimoto, Pedro A F Galante, Célia R S Garcia
According to the World Health Organization (WHO), Plasmodium falciparum is the deadliest parasite among all species. This parasite possesses the ability to sense molecules, including melatonin (MEL) and cAMP, and modulate its cell cycle accordingly. MEL synchronizes the development of this malaria parasite by activating several cascades, including the generation of the second messenger cAMP. Therefore, we performed RNA sequencing (RNA-Seq) analysis in P. falciparum erythrocytic stages (ring, trophozoite and schizont) treated with MEL and cAMP...
September 2016: Genes & Cancer
https://www.readbyqxmd.com/read/28043395/artesunate-tafenoquine-combination-therapy-promotes-clearance-and-abrogates-transmission-of-the-avian-malaria-parasite-plasmodium-gallinaceum
#20
Suchada Tasai, Tawee Saiwichai, Morakot Kaewthamasorn, Sonthaya Tiawsirisup, Prayute Buddhirakkul, Sirintip Chaichalotornkul, Sittiporn Pattaradilokrat
Clinical manifestations of malaria infection in vertebrate hosts arise from the multiplication of the asexual stage parasites in the blood, while the gametocytes are responsible for the transmission of the disease. Antimalarial drugs that target the blood stage parasites and transmissible gametocytes are rare, but are essentially needed for the effective control of malaria and for limiting the spread of resistance. Artemisinin and its derivatives are the current first-line antimalarials that are effective against the blood stage parasites and gametocytes, but resistance to artemisinin has now emerged and spread in various malaria endemic areas...
January 15, 2017: Veterinary Parasitology
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