Sexual Development in Non-Human Parasitic Apicomplexa: Just Biology or Targets for Control?

SUMMARYGametocytes are the specialized form ofPlasmodiumparasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV). In this review, we summarize the current knowledge on immunity against the transmission stages ofPlasmodium. This includes immune responses against epitopes on the gametocyte-infected erythrocyte surface during gametocyte development, as well as epitopes present upon gametocyte activation in the mosquito midgut. We present an analysis of historical data on transmission reducing immunity (TRI), as analysed in mosquito feeding assays, and its correlation with natural recognition of sexual stage specific proteins Pfs48/45 and Pfs230. Although high antibody titres towards either one of these proteins is associated with TRI, the presence of additional, novel targets is anticipated. In conclusion, the identification of novel gametocyte-specific targets of naturally acquired immunity against different gametocyte stages could aid in the development of potential TBV targets and ultimately an effective transmission blocking approach.

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Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians

10.7287/peerj.preprints.27394v1 ◽

2018 ◽

Cited By ~ 4

Author(s):

Hugo Cayuela ◽

Andrés Valenzuela-Sanchez ◽

Loïc Teulier ◽

Íñigo Martínez-Solano ◽

Jean-Paul Léna ◽

...

Keyword(s):

Evolutionary Dynamics ◽

Current Knowledge ◽

Life Cycles ◽

Structured Populations ◽

Model Systems ◽

Suitable Model ◽

Dispersal Patterns ◽

Central Process ◽

Complex Life Cycles ◽

Spatially Structured Populations

Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations, by affecting population growth rate and local colonization-extinction processes. Dispersal can also influence evolutionary processes because it determines rates and patterns of gene flow in spatially structured populations and is closely linked to local adaptation. For these reasons, dispersal has received considerable attention from ecologists and evolutionary biologists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades, researchers have taken an interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography and genetics of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal. In particular, we emphasize the need to (1) quantify dispersal rate and distance rigorously using suitable model systems, (2) investigate the genetic basis and dispersal evolution patterns, and (3) examine dispersal-related eco-evolutionary dynamics. These proposed research avenues tap from the recent advances in quantitative and molecular methods and have the potential to improve our understanding of dispersal in organisms with complex life cycles.

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Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians

10.7287/peerj.preprints.27394 ◽

2018 ◽

Author(s):

Hugo Cayuela ◽

Andrés Valenzuela-Sanchez ◽

Loïc Teulier ◽

Íñigo Martínez-Solano ◽

Jean-Paul Léna ◽

...

Keyword(s):

Evolutionary Dynamics ◽

Current Knowledge ◽

Life Cycles ◽

Structured Populations ◽

Model Systems ◽

Suitable Model ◽

Dispersal Patterns ◽

Central Process ◽

Complex Life Cycles ◽

Spatially Structured Populations

Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations, by affecting population growth rate and local colonization-extinction processes. Dispersal can also influence evolutionary processes because it determines rates and patterns of gene flow in spatially structured populations and is closely linked to local adaptation. For these reasons, dispersal has received considerable attention from ecologists and evolutionary biologists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades, researchers have taken an interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography and genetics of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal. In particular, we emphasize the need to (1) quantify dispersal rate and distance rigorously using suitable model systems, (2) investigate the genetic basis and dispersal evolution patterns, and (3) examine dispersal-related eco-evolutionary dynamics. These proposed research avenues tap from the recent advances in quantitative and molecular methods and have the potential to improve our understanding of dispersal in organisms with complex life cycles.

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Natural Products: A Potential Source of Malaria Transmission Blocking Drugs?

Pharmaceuticals ◽

10.3390/ph13090251 ◽

2020 ◽

Vol 13 (9) ◽

pp. 251

Author(s):

Phanankosi Moyo ◽

Grace Mugumbate ◽

Jacobus N. Eloff ◽

Abraham I. Louw ◽

Vinesh J. Maharaj ◽

...

Keyword(s):

Natural Products ◽

Mosquito Vector ◽

Blocking Drug ◽

Transmission Blocking ◽

Antimalarial Agents ◽

Challenges And Opportunities ◽

Sexual Stages ◽

Derivatives Of ◽

Effective Transmission ◽

Potential Use

The ability to block human-to-mosquito and mosquito-to-human transmission of Plasmodium parasites is fundamental to accomplish the ambitious goal of malaria elimination. The WHO currently recommends only primaquine as a transmission-blocking drug but its use is severely restricted by toxicity in some populations. New, safe and clinically effective transmission-blocking drugs therefore need to be discovered. While natural products have been extensively investigated for the development of chemotherapeutic antimalarial agents, their potential use as transmission-blocking drugs is comparatively poorly explored. Here, we provide a comprehensive summary of the activities of natural products (and their derivatives) of plant and microbial origins against sexual stages of Plasmodium parasites and the Anopheles mosquito vector. We identify the prevailing challenges and opportunities and suggest how these can be mitigated and/or exploited in an endeavor to expedite transmission-blocking drug discovery efforts from natural products.

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Alternative bacteriophage life cycles: the carrier state of Campylobacter jejuni

Open Biology ◽

10.1098/rsob.130200 ◽

2014 ◽

Vol 4 (3) ◽

pp. 130200 ◽

Cited By ~ 34

Author(s):

Patcharin Siringan ◽

Phillippa L. Connerton ◽

Nicola J. Cummings ◽

Ian F. Connerton

Keyword(s):

Campylobacter Jejuni ◽

Pathogenic Bacteria ◽

Carrier State ◽

Life Cycles ◽

Enteric Disease ◽

New Host ◽

Complex Life Cycles ◽

Phenotypic Changes ◽

Poultry Products ◽

New Hosts

Members of the genus Campylobacter are frequently responsible for human enteric disease, often through consumption of contaminated poultry products. Bacteriophages are viruses that have the potential to control pathogenic bacteria, but understanding their complex life cycles is key to their successful exploitation. Treatment of Campylobacter jejuni biofilms with bacteriophages led to the discovery that phages had established a relationship with their hosts typical of the carrier state life cycle (CSLC), where bacteria and bacteriophages remain associated in equilibrium. Significant phenotypic changes include improved aerotolerance under nutrient-limited conditions that would confer an advantage to survive in extra-intestinal environments, but a lack in motility eliminated their ability to colonize chickens. Under these circumstances, phages can remain associated with a compatible host and continue to produce free virions to prospect for new hosts. Moreover, we demonstrate that CSLC host bacteria can act as expendable vehicles for the delivery of bacteriophages to new host bacteria within pre-colonized chickens. The CSLC represents an important phase in the ecology of Campylobacter bacteriophage.

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Definitions and concepts of reproductive biology of diatoms (terminological glossary)

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2017.51.71 ◽

2017 ◽

Vol 51 ◽

pp. 71-105 ◽

Cited By ~ 3

Author(s):

N. A. Davidovich

Keyword(s):

Mating System ◽

Sexual Reproduction ◽

Reproductive Biology ◽

World Literature ◽

Russian Literature ◽

Life Cycles ◽

Transfer Of Knowledge ◽

Research Experience ◽

Key Terms

The absence of a conceptual terminology, sufficiently developed and widely accepted in the Russian literature, significantly hinders progress in the field of reproductive biology of diatoms, restricts communication and debate, prevents training and transfer of knowledge. The present work is an attempt, based on world literature and our own research experience, to summarize, systematize, add, and clarify the existing terms, concepts and definitions related to research which are focused on sex and sexual reproduction in diatoms. A glossary of key terms (more than 200, including synonyms) is provided. Terms refer to diatom reproductive biology, life cycles, fertilization, mating system, gender (including inheritance and determination of sex, as well as inheritance associated with sex). Contradictions between possible interpretations of certain terms are briefly discussed.

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Molecular Basis of Apomixis in Plants

Genes ◽

10.3390/genes12040576 ◽

2021 ◽

Vol 12 (4) ◽

pp. 576

Author(s):

Diego Hojsgaard

Keyword(s):

Sexual Reproduction ◽

Molecular Basis ◽

The Creation ◽

New Generation

Sexual reproduction in plants is a complex, stringently regulated process that leads to the creation of diaspores for a new generation: sexual seeds [...]

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Foamy Viruses, Bet, and APOBEC3 Restriction

Viruses ◽

10.3390/v13030504 ◽

2021 ◽

Vol 13 (3) ◽

pp. 504

Author(s):

Ananda Ayyappan Jaguva Vasudevan ◽

Daniel Becker ◽

Tom Luedde ◽

Holger Gohlke ◽

Carsten Münk

Keyword(s):

Current Knowledge ◽

Regulatory Protein ◽

Host Population ◽

Life Cycles ◽

Restriction Factors ◽

Host Restriction ◽

Open Questions ◽

Foamy Viruses ◽

Natural Hosts ◽

Hiv 1

Non-human primates (NHP) are an important source of viruses that can spillover to humans and, after adaptation, spread through the host population. Whereas HIV-1 and HTLV-1 emerged as retroviral pathogens in humans, a unique class of retroviruses called foamy viruses (FV) with zoonotic potential are occasionally detected in bushmeat hunters or zookeepers. Various FVs are endemic in numerous mammalian natural hosts, such as primates, felines, bovines, and equines, and other animals, but not in humans. They are apathogenic, and significant differences exist between the viral life cycles of FV and other retroviruses. Importantly, FVs replicate in the presence of many well-defined retroviral restriction factors such as TRIM5α, BST2 (Tetherin), MX2, and APOBEC3 (A3). While the interaction of A3s with HIV-1 is well studied, the escape mechanisms of FVs from restriction by A3 is much less explored. Here we review the current knowledge of FV biology, host restriction factors, and FV–host interactions with an emphasis on the consequences of FV regulatory protein Bet binding to A3s and outline crucial open questions for future studies.

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