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https://www.readbyqxmd.com/read/28109049/production-of-the-antibiotic-secondary-metabolite-solanapyrone-a-by-the-fungal-plant-pathogen-ascochyta-rabiei-during-fruiting-body-formation-in-saprobic-growth
#1
Wonyong Kim, Jeong-Jin Park, Frank M Dugan, Tobin L Peever, David R Gang, George Vandemark, Weidong Chen
Fungi are noted producers of a diverse array of secondary metabolites, many of which are of pharmacological importance. However, the biological roles of the vast majority of these molecules during the fungal life cycle in nature remain elusive. Solanapyrones are polyketide-derived secondary metabolites produced by diverse fungal species including the plant pathogen Ascochyta rabiei. This molecule was originally thought to function as a phytotoxin facilitating pathogenesis of A. rabiei. Chemical profiling and gene expression studies showed that solanapyrone A was specifically produced during saprobic, but not parasitic growth of A...
January 21, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28107502/rnai-based-functional-genomics-identifies-new-virulence-determinants-in-mucormycosis
#2
Trung Anh Trieu, María Isabel Navarro-Mendoza, Carlos Pérez-Arques, Marta Sanchis, Javier Capilla, Patricia Navarro-Rodriguez, Loida Lopez-Fernandez, Santiago Torres-Martínez, Victoriano Garre, Rosa María Ruiz-Vázquez, Francisco E Nicolás
Mucorales are an emerging group of human pathogens that are responsible for the lethal disease mucormycosis. Unfortunately, functional studies on the genetic factors behind the virulence of these organisms are hampered by their limited genetic tractability, since they are reluctant to classical genetic tools like transposable elements or gene mapping. Here, we describe an RNAi-based functional genomic platform that allows the identification of new virulence factors through a forward genetic approach firstly described in Mucorales...
January 20, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28105571/metal-stress-in-zooplankton-diapause-production-post-hatching-response
#3
Adriana Aránguiz-Acuña, Pablo Pérez-Portilla
Aquatic organisms commonly respond to harsh conditions by forming diapausing stages, which enable populations to survive adverse periods forming egg banks. Production of diapausing eggs is frequently observed in monogonont rotifers, previously changing from asexual to partial sexual reproduction (mixis). In despite that zooplankton are frequently used in ecotoxicological assessment because of their sensitivity to various toxicants and their important role in the ecosystems, toxicity evaluations often consider the directly exposed population produced by parthenogenetic reproduction, exclusively...
January 19, 2017: Ecotoxicology
https://www.readbyqxmd.com/read/28104756/sugar-nucleotide-quantification-by-liquid-chromatography-tandem-mass-spectrometry-reveals-a-distinct-profile-in-plasmodium-falciparum-sexual-stage-parasites
#4
Borja López-Gutiérrez, Rhoel R Dinglasan, Luis Izquierdo
The obligate intracellular lifestyle of Plasmodium falciparum and the difficulties to obtain sufficient amounts of biological material has hampered the study of specific metabolic pathways in the malaria parasite. Thus, for example, the pools of sugar nucleotides required to fuel glycosylation reactions have never been studied in-depth in well-synchronized asexual parasites or in other stages of its life cycle. These metabolites are of critical importance, especially considering the renewed interest in the presence of N -, O - and other glycans in key parasite proteins...
January 19, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28100927/resolution-of-morphology-based-taxonomic-delusions-acrocordiella-basiseptospora-blogiascospora-clypeosphaeria-hymenopleella-lepteutypa-pseudapiospora-requienella-seiridium-and-strickeria
#5
W M Jaklitsch, A Gardiennet, H Voglmayr
Fresh material, type studies and molecular phylogeny were used to clarify phylogenetic relationships of the nine genera Acrocordiella, Blogiascospora, Clypeosphaeria, Hymenopleella, Lepteutypa, Pseudapiospora, Requienella, Seiridium and Strickeria. At first sight, some of these genera do not seem to have much in common, but all were found to belong to the Xylariales, based on their generic types. Thus, the most peculiar finding is the phylogenetic affinity of the genera Acrocordiella, Requienella and Strickeria, which had been classified in the Dothideomycetes or Eurotiomycetes, to the Xylariales...
December 2016: Persoonia
https://www.readbyqxmd.com/read/28096162/impact-of-extended-artesunate-duration-on-parasitological-outcome-in-a-cytocidal-murine-malaria-model
#6
Leah A Walker, David J Sullivan
Artemisinin-based combination therapies are a key pillar in global malaria control and are recommended as a first-line Plasmodium falciparum treatment. They rely upon a rapid, 4-log reduction in parasitemia by artemisinin compounds with a short half-life and the killing of remaining parasites by a partner compound with a longer half-life. Current treatment guidelines stipulate giving three 24 hour interval doses or six 12 hour interval doses over a 3-day period. Due to the short half-life of artesunate and artemether, almost all of the resulting cytocidal activity is confined within a single 48 hour asexual P...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28092805/circumstantial-evidence-of-life-history-events-in-loricate-choanoflagellates
#7
Helge Abildhauge Thomsen, Jette Buch Østergaard
Sex is found in all major eukaryotic groups of organisms. It has been known for some time that the choanoflagellates also possess the genes involved in meiosis and a full sexual cycle was also recently accounted for in Salpingoeca rosetta. With reference to the loricate choanoflagellates the current status is that only circumstantial evidence, from wild material of Bicosta spinifera, exists in favour of documenting division patterns that go beyond plain asexual division, and that has the potential to represent stages in a sexual life cycle...
December 27, 2016: European Journal of Protistology
https://www.readbyqxmd.com/read/28091971/mate-limitation-in-fungal-plant-parasites-can-lead-to-cyclic-epidemics-in-perennial-host-populations
#8
Virginie Ravigné, Valérie Lemesle, Alicia Walter, Ludovic Mailleret, Frédéric M Hamelin
Fungal plant parasites represent a growing concern for biodiversity and food security. Most ascomycete species are capable of producing different types of infectious spores both asexually and sexually. Yet the contributions of both types of spores to epidemiological dynamics have still to been fully researched. Here we studied the effect of mate limitation in parasites which perform both sexual and asexual reproduction in the same host. Since mate limitation implies positive density dependence at low population density, we modeled the dynamics of such species with both density-dependent (sexual) and density-independent (asexual) transmission rates...
January 13, 2017: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/28091869/a-positive-approach-toward-asexuality-some-first-steps-but-still-a-long-way-to-go
#9
Ellen Van Houdenhove, Paul Enzlin, Luk Gijs
No abstract text is available yet for this article.
January 13, 2017: Archives of Sexual Behavior
https://www.readbyqxmd.com/read/28091617/switch-from-sexual-to-parthenogenetic-reproduction-in-a-zebra-shark
#10
Christine L Dudgeon, Laura Coulton, Ren Bone, Jennifer R Ovenden, Severine Thomas
Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28087777/genome-sequencing-reveals-the-origin-of-the-allotetraploid-arabidopsis-suecica
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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