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Human asexuality

Marzieh Ezzaty Mirhashemi, Farzad Noubary, Susan Chapman-Bonofiglio, Saul Tzipori, Gordon S Huggins, Giovanni Widmer
BACKGROUND: Human cryptosporidiosis is caused primarily by two species of apicomplexan protozoa, Cryptosporidium parvum and C. hominis. In cultured cell monolayers, the parasite undergoes two generations of asexual multiplication (merogony). However, the proportion of parasites completing the life-cycle is low and insufficient to sustain continuous propagation. Due to the intracellular location of meronts and later life-cycle stages, oocyst and sporozoites are the only forms of the parasite that can readily be isolated...
March 12, 2018: Parasites & Vectors
Jiyoung Shin, Jung-Eun Kim, Yin-Won Lee, Hokyoung Son
Cytochrome P450s (CYPs), heme-containing monooxygenases, play important roles in a wide variety of metabolic processes important for development as well as biotic/trophic interactions in most living organisms. Functions of some CYP enzymes are similar across organisms, but some are organism-specific; they are involved in the biosynthesis of structural components, signaling networks, secondary metabolisms, and xenobiotic/drug detoxification. Fungi possess more diverse CYP families than plants, animals, or bacteria...
March 7, 2018: Toxins
Hella Schmidt, Sebastian Vlaic, Thomas Krüger, Franziska Schmidt, Johannes Balkenhohl, Thomas Dandekar, Reinhard Guthke, Olaf Kniemeyer, Thorsten Heinekamp, Axel A Brakhage
Invasive infections by the human pathogenic fungus Aspergillus fumigatus start with the outgrowth of asexual, airborne spores (conidia) into the lung tissue of immunocompromised patients. The resident alveolar macrophages phagocytose conidia, which end up in phagolysosomes. However, A. fumigatus conidia resist phagocytic degradation to a certain degree. This is mainly attributable to the pigment 1,8-dihydroxynaphthalene (DHN) melanin located in the cell wall of conidia, which manipulates the phagolysosomal maturation and prevents their intracellular killing...
March 5, 2018: Molecular & Cellular Proteomics: MCP
Sabine A Fraschka, Michael Filarsky, Regina Hoo, Igor Niederwieser, Xue Yan Yam, Nicolas M B Brancucci, Franziska Mohring, Annals T Mushunje, Ximei Huang, Peter R Christensen, Francois Nosten, Zbynek Bozdech, Bruce Russell, Robert W Moon, Matthias Marti, Peter R Preiser, Richárd Bártfai, Till S Voss
Heterochromatin-dependent gene silencing is central to the adaptation and survival of Plasmodium falciparum malaria parasites, allowing clonally variant gene expression during blood infection in humans. By assessing genome-wide heterochromatin protein 1 (HP1) occupancy, we present a comprehensive analysis of heterochromatin landscapes across different Plasmodium species, strains, and life cycle stages. Common targets of epigenetic silencing include fast-evolving multi-gene families encoding surface antigens and a small set of conserved HP1-associated genes with regulatory potential...
February 22, 2018: Cell Host & Microbe
Isaie J Reuling, Lisanne A van de Schans, Luc E Coffeng, Kjerstin Lanke, Lisette Meerstein-Kessel, Wouter Graumans, Geert-Jan van Gemert, Karina Teelen, Rianne Siebelink-Stoter, Marga van de Vegte-Bolmer, Quirijn de Mast, André J van der Ven, Karen Ivinson, Cornelus C Hermsen, Sake de Vlas, John Bradley, Katharine A Collins, Christian F Ockenhouse, James McCarthy, Robert W Sauerwein, Teun Bousema
Background Malaria elimination strategies require a thorough understanding of parasite transmission from human to mosquito. A clinical model to induce gametocytes to understand their dynamics and evaluate transmission-blocking interventions (TBI) is currently unavailable. Here, we explore the use of the well-established Controlled Human Malaria Infection model (CHMI) to induce gametocyte carriage with different antimalarial drug regimens. Methods In a single centre, open-label randomised trial, healthy malaria-naive participants (aged 18-35 years) were infected with Plasmodium falciparum by bites of infected Anopheles mosquitoes (ClinicalTrials...
February 27, 2018: ELife
Rafaela S Fernandes, Luis G V Fernandes, Andre S de Godoy, Patrícia A Miyasato, Eliana Nakano, Leonardo P Farias, Ana L T O Nascimento, Luciana C C Leite
Schistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma which have a complex life cycle characterized by an asexual multiplication in the snail intermediate host and a sexual reproduction phase in the mammalian definitive host. The initial steps of the human host infection involve the secretion of proteins contained in the acetabular glands of cercariae that promote parasite adhesion and proteolysis of the skin layers. Herein, we performed a functional analysis of SmVAL18, identified as one of the three SCP/TAPS proteins constituent of cercarial secretions...
February 22, 2018: Molecular and Biochemical Parasitology
Gabriela F Persinoti, Diego A Martinez, Wenjun Li, Aylin Döğen, R Blake Billmyre, Anna Averette, Jonathan M Goldberg, Terrance Shea, Sarah Young, Qiandong Zeng, Brian G Oliver, Richard Barton, Banu Metin, Süleyha Hilmioğlu-Polat, Macit Ilkit, Yvonne Gräser, Nilce M Martinez-Rossi, Theodore C White, Joseph Heitman, Christina A Cuomo
Dermatophytes include fungal species that infect humans, as well as those which also infect other animals or only grow in the environment. The dermatophyte species Trichophyton rubrum is a frequent cause of skin infection in immunocompetent individuals. While members of the T. rubrum species complex have been further categorized based on various morphologies, the population structure and ability to undergo sexual reproduction are not well understood. In this study, we analyze a large set of T. rubrum and Trichophyton interdigitale isolates to examine mating types, evidence of mating, and genetic variation...
February 21, 2018: Genetics
S Richard, J M G C F Almeida, O H Cissé, A Luraschi, O Nielsen, M Pagni, P M Hauser
Fungi of the genus Pneumocystis are obligate parasites that colonize mammals' lungs and are host species specific. Pneumocystis jirovecii and Pneumocystis carinii infect, respectively, humans and rats. They can turn into opportunistic pathogens in immunosuppressed hosts, causing severe pneumonia. Their cell cycle is poorly known, mainly because of the absence of an established method of culture in vitro It is thought to include both asexual and sexual phases. Comparative genomic analysis suggested that their mode of sexual reproduction is primary homothallism involving a single mating type ( MAT ) locus encompassing plus and minus genes ( matMc , matMi , and matPi ; Almeida et al...
February 20, 2018: MBio
Nina Simon, Oliver Friedrich, Barbara Kappes
The human complement system is the most effective defense mechanism of the human innate immune system. One major negative regulator of the alternative pathway in human blood is complement factor H (FH). It binds to autologous cells and thus, prevents complement attack against body-cells or tissues. Various pathogens are known to escape complement recognition by recruiting FH to provide protection against the host's immune system. This immune evasion mechanism was recently qualitatively reported for asexual malaria blood stages...
February 12, 2018: Vaccine
Yudi T Pinilla, Stefanie C P Lopes, Vanderson S Sampaio, Francys S Andrade, Gisely C Melo, Alessandra S Orfanó, Nágila F C Secundino, Maria G V B Guerra, Marcus V G Lacerda, Kevin C Kobylinski, Karin S Escobedo-Vargas, Victor M López-Sifuentes, Craig A Stoops, G Christian Baldeviano, Joel Tarning, Gissella M Vasquez, Paulo F P Pimenta, Wuelton M Monteiro
BACKGROUND: The mosquito resistance to the insecticides threatens malaria control efforts, potentially becoming a major public health issue. Alternative methods like ivermectin (IVM) administration to humans has been suggested as a possible vector control to reduce Plasmodium transmission. Anopheles aquasalis and Anopheles darlingi are competent vectors for Plasmodium vivax, and they have been responsible for various malaria outbreaks in the coast of Brazil and the Amazon Region of South America...
February 14, 2018: PLoS Neglected Tropical Diseases
Shilpy Aggarwal, Deepika Paliwal, Dhirender Kaushik, Girish Kumar Gupta, Ajay Kumar
BACKGROUND: Malaria, one of the most vital infectious diseases caused by protozoan parasites of the Plasmodium genus. As P. falciparum, the cause of most of the severe cases of malaria, is increasingly resistant to available drugs such as amodioquine, chloroquine, artemisinin, and antifolates, there is an urgent need of identify new targets for chemotherapy Objective: This study screened novel pyrazole derivatives carrying iminium & benzothiazole group for antimalarial potential against P...
February 12, 2018: Combinatorial Chemistry & High Throughput Screening
J Li, G Guo, Z Z Zhang, W B Zhang
Alveolar and cystic echinococcosis are important zoonotic diseases caused by the dog/fox tapeworms of Echinococcus granulosus and E. multilocularis, which are distributed in almost whole the world. The diseases remarkably impact on the people's health and economic development of communities. Echinococcus tapeworms need two mammalian animals to complete their lifecycle. The worms undergo different developmental stages (adult, egg/oncosphere, cyst, and protoscolex). Each stage has its own distinct physiological characteristics...
February 6, 2018: Zhonghua Yu Fang Yi Xue za Zhi [Chinese Journal of Preventive Medicine]
Amena Khatun, Tarin Farhana, Abdullah As Sabir, Shah Mohammad Naimul Islam, Helen M West, Mahfuzur Rahman, Tofazzal Islam
The objective of this study was to isolate and characterize antagonistic rhizobacteria from chili against a notorious phytopathogen Phytophthora capsici. Among the 48 bacteria isolated, BTLbbc-02, BTLbbc-03, and BTLbbc-05 were selected based on their inhibitory activity against P. capsici. They were tentatively identified as Burkholderia metallica BTLbbc-02, Burkholderia cepacia BTLbbc-03, and Pseudomonas aeruginosa BTLbbc-05, respectively, based on their 16S rRNA gene sequencing. All inhibited the growth of P...
February 3, 2018: Zeitschrift Für Naturforschung. C, A Journal of Biosciences
Katharine A Collins, Claire Yt Wang, Matthew Adams, Hayley Mitchell, Melanie Rampton, Suzanne Elliott, Isaie J Reuling, Teun Bousema, Robert Sauerwein, Stephan Chalon, Jörg J Möhrle, James S McCarthy
BACKGROUND: Drugs and vaccines that can interrupt the transmission of Plasmodium falciparum will be important for malaria control and elimination. However, models for early clinical evaluation of candidate transmission-blocking interventions are currently unavailable. Here we describe a new model for evaluating malaria transmission from humans to Anopheles mosquitoes using controlled human malaria infection (CHMI). METHODS: Seventeen healthy malaria-naïve volunteers underwent CHMI by intravenous inoculation of P...
February 1, 2018: Journal of Clinical Investigation
Nathalie Dinguirard, Codie Heinemann, Timothy P Yoshino
Human blood flukes, Schistosoma spp., have a complex life cycle that involves asexual and sexual developmental phases within a snail intermediate and mammalian final host, respectively. The ability to isolate and sustain the different life cycle stages under in vitro culture conditions has greatly facilitated investigations of the cellular, biochemical and molecular mechanisms regulating parasite growth, development and host interactions. Transmission of schistosomiasis requires asexual reproduction and development of multiple larval stages within the snail host; from the infective miracidium, through primary and secondary sporocysts, to the final cercarial stage that is infective to humans...
January 14, 2018: Journal of Visualized Experiments: JoVE
Gowtham Subramanian, Meenakshi A Belekar, Anurag Shukla, Jie Xin Tong, Ameya Sinha, Trang T T Chu, Akshay S Kulkarni, Peter R Preiser, D Srinivasa Reddy, Kevin S W Tan, Dhanasekaran Shanmugam, Rajesh Chandramohanadas
The Malaria Box collection includes 400 chemically diverse small molecules with documented potency against malaria parasite growth, but the underlying modes of action are largely unknown. Using complementary phenotypic screens against Plasmodium falciparum and Toxoplasma gondii, we report phenotype-specific hits based on inhibition of overall parasite growth, apicoplast segregation, and egress or host invasion, providing hitherto unavailable insights into the possible mechanisms affected. First, the Malaria Box library was screened against tachyzoite stage T...
January 2018: MSphere
Kehinde Adebayo Babatunde, Smart Mbagwu, María Andrea Hernández-Castañeda, Swamy R Adapa, Michael Walch, Luis Filgueira, Laurent Falquet, Rays H Y Jiang, Ionita Ghiran, Pierre-Yves Mantel
The parasite Plasmodium falciparum causes the most severe form of malaria. Cell communication between parasites is an important mechanism to control population density and differentiation. The infected red blood cells (iRBCs) release small extracellular vesicles (EVs) that transfer cargoes between cells. The EVs synchronize the differentiation of the asexual parasites into gametocytes to initiate the transmission to the mosquito. Beside their role in parasite communication, EVs regulate vascular function. So far, the exact cargoes responsible for cellular communication remain unknown...
January 17, 2018: Scientific Reports
Jeferson Camargo de Lima, Karina Mariante Monteiro, Tatiana Noel Basika Cabrera, Gabriela Prado Paludo, Hercules Moura, John R Barr, Arnaldo Zaha, Henrique Bunselmeyer Ferreira
Mesocestoides corti is a widely used model for the study of cestode biology, and its transition from the larval tetrathyridium (TT) stage to the strobilated, adult worm (ST) stage can be induced and followed in vitro. Here, a proteomic approach was used to describe and compare M. corti TT and ST protein repertories. Overall, 571 proteins were identified, 238 proteins in TT samples and 333 proteins in ST samples. Among the identified proteins, 207 proteins were shared by TTs and STs, while 157 were stage-specific, being 31 exclusive from TTs, and 126 from STs...
January 6, 2018: Journal of Proteomics
Mayumi Tachibana, Tomoko Ishino, Eizo Takashima, Takafumi Tsuboi, Motomi Torii
Anopheles mosquitoes transmit Plasmodium parasites of mammals, including the species that cause malaria in humans. Malaria pathology is caused by rapid multiplication of parasites in asexual intraerythrocytic cycles. Sexual stage parasites are also produced during the intraerythrocytic cycle, and are ingested by the mosquito, initiating gametogenesis and subsequent sporogonic stage development. Here, we present a Plasmodium protein, termed microgamete surface protein (MiGS), which has an important role in male gametocyte osmiophilic body (MOB) formation and microgamete function...
January 5, 2018: Cellular Microbiology
Linda E Amoah, Festus K Acquah, Ruth Ayanful-Torgby, Akua Oppong, Joana Abankwa, Evans K Obboh, Susheel K Singh, Michael Theisen
BACKGROUND: During a Plasmodium infection, exposure of human host immune cells to both the asexual and the sexual stages of the parasite elicit immune responses. These responses may be protective and prevent the development of high parasitaemia and its associated clinical symptoms, or block the transmission of malaria to an uninfected person. This study aimed at examining the dynamics of naturally acquired immune responses against the asexual and sexual forms of Plasmodium falciparum as well as assessing differences in the multiplicity of infection (MOI) in asymptomatic Ghanaian children living in two communities with varying malaria transmission intensities...
January 5, 2018: Parasites & Vectors
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