scholarly journals Are all red algal parasites cut from the same cloth?

2014 ◽  
Vol 83 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Eric D. Salomaki ◽  
Christopher E. Lane
Keyword(s):  
Red Algae ◽  
Alternative Hypothesis ◽  
Future Research ◽  
Close Relative ◽  
Life Strategy ◽  
Cellular Interactions ◽  
Human Pathogens ◽  
Late 20Th Century ◽  
Red Algal ◽  
Parasite Evolution

Parasitism is a common life strategy throughout the eukaryotic tree of life. Many devastating human pathogens, including the causative agents of malaria and toxoplasmosis, have evolved from a photosynthetic ancestor. However, how an organism transitions from a photosynthetic to a parasitic life history strategy remains mostly unknown. This is largely because few systems present the opportunity to make meaningful comparisons between a parasite and a close free-living relative. Parasites have independently evolved dozens of times throughout the Florideophyceae (Rhodophyta), and often infect close relatives. The accepted evolutionary paradigm proposes that red algal parasites arise by first infecting a close relative and over time diversify and infect more distantly related species. This provides a natural evolutionary gradient of relationships between hosts and parasites that share a photosynthetic common ancestor. Elegant microscopic work in the late 20th century provided detailed insight into the infection cycle of red algal parasites and the cellular interactions between parasites and their hosts. Those studies led to the use of molecular work to further investigate the origins of the parasite organelles and reveal the evolutionary relationships between hosts and their parasites. Here we synthesize the research detailing the infection methods and cellular interactions between red algal parasites and their hosts. We offer an alternative hypothesis to the current dogma of red algal parasite evolution and propose that red algae can adopt a parasitic life strategy through multiple evolutionary pathways, including direct infection of distant relatives. Furthermore, we highlight potential directions for future research to further evaluate parasite evolution in red algae.

scholarly journals Red algal parasites: A synopsis of described species, their hosts, distinguishing characters and areas for continued research

2020 ◽  
Author(s):  
Maren Preuss ◽  
WA Nelson ◽  
Giuseppe Zuccarello
Keyword(s):  
Host Cell ◽  
Red Algae ◽  
Host Cells ◽  
Parasite Development ◽  
Cellular Interactions ◽  
Cell Control ◽  
Full Extent ◽  
Red Algal ◽  
Algal Groups ◽  
Parasite Biodiversity

© 2017 Walter de Gruyter GmbH, Berlin/Boston. Red algal parasites are diverse organisms that are unusual due to the fact that many are closely related to their hosts. Parasitism has developed many times within different red algal groups, but the full extent of parasite biodiversity is unknown, as parasites are easily overlooked due to their small size and often low abundance. Additionally, the literature on red algal parasites is dispersed and has not been compiled in over 30 years. Although criteria have been proposed to define what constitutes a red algal parasite, many parasites are poorly described, and the cellular interactions with their host are poorly known. A few studies have demonstrated that parasites transfer organelles to host cells, which can alter the physiology of the host to the benefit of the parasite. Here, we apply a set of defining criteria for parasites to a compiled list of all described red algal parasites. Our results highlight the lack of knowledge of many key parasitic processes including early parasite development, host cell "control", and parasite origin. Until the biology of more parasites is studied, generalisations on the processes of parasitism in red algae may be premature. We hope this synopsis will stimulate research into this fascinating group.

scholarly journals Red algal parasites: A synopsis of described species, their hosts, distinguishing characters and areas for continued research

2020 ◽  
Author(s):  
Maren Preuss ◽  
WA Nelson ◽  
Giuseppe Zuccarello
Keyword(s):  
Host Cell ◽  
Red Algae ◽  
Host Cells ◽  
Parasite Development ◽  
Cellular Interactions ◽  
Cell Control ◽  
Full Extent ◽  
Red Algal ◽  
Algal Groups ◽  
Parasite Biodiversity

© 2017 Walter de Gruyter GmbH, Berlin/Boston. Red algal parasites are diverse organisms that are unusual due to the fact that many are closely related to their hosts. Parasitism has developed many times within different red algal groups, but the full extent of parasite biodiversity is unknown, as parasites are easily overlooked due to their small size and often low abundance. Additionally, the literature on red algal parasites is dispersed and has not been compiled in over 30 years. Although criteria have been proposed to define what constitutes a red algal parasite, many parasites are poorly described, and the cellular interactions with their host are poorly known. A few studies have demonstrated that parasites transfer organelles to host cells, which can alter the physiology of the host to the benefit of the parasite. Here, we apply a set of defining criteria for parasites to a compiled list of all described red algal parasites. Our results highlight the lack of knowledge of many key parasitic processes including early parasite development, host cell "control", and parasite origin. Until the biology of more parasites is studied, generalisations on the processes of parasitism in red algae may be premature. We hope this synopsis will stimulate research into this fascinating group.

scholarly journals Red algal parasites: a synopsis of described species, their hosts, distinguishing characters and areas for continued research

2017 ◽  
Vol 60 (1) ◽  
Author(s):  
Maren Preuss ◽  
Wendy A. Nelson ◽  
Giuseppe C. Zuccarello
Keyword(s):  
Host Cell ◽  
Red Algae ◽  
Host Cells ◽  
Parasite Development ◽  
Cellular Interactions ◽  
Cell Control ◽  
Full Extent ◽  
Red Algal ◽  
Algal Groups ◽  
Parasite Biodiversity

AbstractRed algal parasites are diverse organisms that are unusual due to the fact that many are closely related to their hosts. Parasitism has developed many times within different red algal groups, but the full extent of parasite biodiversity is unknown, as parasites are easily overlooked due to their small size and often low abundance. Additionally, the literature on red algal parasites is dispersed and has not been compiled in over 30 years. Although criteria have been proposed to define what constitutes a red algal parasite, many parasites are poorly described, and the cellular interactions with their host are poorly known. A few studies have demonstrated that parasites transfer organelles to host cells, which can alter the physiology of the host to the benefit of the parasite. Here, we apply a set of defining criteria for parasites to a compiled list of all described red algal parasites. Our results highlight the lack of knowledge of many key parasitic processes including early parasite development, host cell “control”, and parasite origin. Until the biology of more parasites is studied, generalisations on the processes of parasitism in red algae may be premature. We hope this synopsis will stimulate research into this fascinating group.

scholarly journals The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid

2006 ◽  
Vol 72 (3) ◽  
pp. 1956-1965 ◽  
Author(s):  
Anne-Marie Grenier ◽  
Gabrielle Duport ◽  
Sylvie Pagès ◽  
Guy Condemine ◽  
Yvan Rahbé
Keyword(s):  
Acyrthosiphon Pisum ◽  
Ecological Impact ◽  
Sitophilus Oryzae ◽  
Pea Aphid ◽  
Erwinia Chrysanthemi ◽  
Future Research ◽  
Close Relative ◽  
Bacterial Cells ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium

ABSTRACT Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

scholarly journals Potential Epigenetic Mechanism(s) Associated With the Persistence of Psychoneurological Symptoms in Women Receiving Chemotherapy for Breast Cancer

2013 ◽  
Vol 16 (2) ◽  
pp. 160-174 ◽  
Author(s):  
Debra Lyon ◽  
Lynne Elmore ◽  
Noran Aboalela ◽  
Jacqueline Merrill-Schools ◽  
Nancy McCain ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Sleep Disturbances ◽  
Alternative Hypothesis ◽  
Epigenetic Mechanism ◽  
Future Research ◽  
Epigenetic Alterations ◽  
Inflammatory Activation ◽  
Epigenetic Patterns ◽  
Psychoneurological Symptoms ◽  
Circulating Levels

Due to recent treatment advances, there have been improvements in the proportion of women surviving a diagnosis of breast cancer (BC). However, many of these survivors report persistent adverse side effects following treatment, such as cognitive dysfunction, depressive symptoms, anxiety, fatigue, sleep disturbances, and pain. Investigators have examined circulating levels of inflammatory markers, particularly serum cytokines, for a potential causal relationship to the development/persistence of these psychoneurological symptoms (PNS). While inflammatory activation, resulting from perceived stress or other factors, may directly contribute to the development of PNS, we offer an alternative hypothesis, suggesting that these symptoms are an early step in a cascade of biological changes leading to epigenetic alterations at the level of deoxyribonucleic acid (DNA) methylation, histone modifications, and/or chromatin structure/chromosomal instability. Given that epigenetic patterns have plasticity, if this conjectured relationship between epigenomic/acquired genomic alterations and the development/persistence of PNS is confirmed, it could provide foundational knowledge for future research leading to the recognition of predictive markers and/or treatments to alleviate PNS in women with BC. In this article, we discuss an evolving theory of the biological basis of PNS, integrating knowledge related to inflammation and DNA repair in the context of genetic and epigenetic science to expand the paradigm for understanding symptom acquisition/persistence following chemotherapy.

scholarly journals Investigating diversity, evolution, development and physiology of red algal parasites from New Zealand

2021 ◽  
Author(s):  
◽  
Maren Preuss
Keyword(s):  
Host Species ◽  
High Throughput Sequencing ◽  
Phylogenetic Analyses ◽  
Host Cells ◽  
Gene Content ◽  
Infected Host ◽  
Parasite Development ◽  
Future Research ◽  
Mitochondrial Genomes ◽  
Red Algal

<p>Red algal parasites have evolved independently over a 100 times and grow only on other red algal hosts. Most parasites are closely related to their host based on the similarity of their reproductive structures. Secondary pit connections between red algal parasites and their hosts are used to transfer parasite organelles and nuclei into host cells. Morphological and physiological changes in infected host cells have been observed in some species. Parasite mitochondrial genomes are similar in size and gene content to free-living red algae whereas parasite plastids are highly reduced. Overall, red algal parasites are poorly studied and thus the aim of this study was to increase the general knowledge of parasitic taxa with respect to their diversity, evolutionary origin, development, physiology, and organelle evolution. Investigation of the primary literature showed that most species descriptions of red algal parasites were poor and did not meet the criteria for defining a parasitic relationship. This literature study also revealed a lack of knowledge of many key parasitic processes including early parasite development, host cell “control”, and parasite origin. Many of these poorly studied research areas were addressed in this thesis. Phylogenetic analyses, using a range of markers from all three genomes (cpDNA: rbcL, nDNA: actin, LSU rRNA; mtDNA: cox1), showed different patterns of phylogenetic relationships for the four new red algal parasites and their hosts. The parasites Phycodrys novae-zelandiophila sp. nov. and Vertebrata aterrimophila sp. nov. closest relative is its host species. Cladhymenia oblongifoliophila sp. nov. closest relative is its host species based on nuclear and mitochondrial markers whereas the plastid markers group the parasite with Cladhymenia lyallii, suggesting that the parasite plastid was acquired when previously parasitizing C. lyallii. Judithia parasitica sp. nov. grows on two Blastophyllis species but the parasites’ closest relative is the non-host species Judithia delicatissima. Developmental studies of the parasite Vertebrata aterrimophila, showed a unique developmental structure (“trunk-like” cell) not known in other parasites, plus localised infection vi and few changes in infected host cells. High-throughput-sequencing revealed mitochondrial genomes of similar size, gene content and order in the parasite Pterocladiophila hemisphaerica to its host Pterocladia lucida, and a reduced non-photosynthetic plastid in the parasite. Mitochondrial (mt) and plastid (cp) genome phylogenies placed Pterocladiophila hemisphaerica on long branches, either as sister to Ceramiales (mt) or Gracilariales (cp). Further analyses, filtering non-elevated plastid genes grouped the parasite neither with the Gracilariales (mt) or Gelidiales (cp) on shorter branches but without support. Nuclear phylogeny grouped P. hemisphaerica as sister to the Gelidiales and other red algal orders and was the only phylogenetic relationship with support. Investigations of photosystem II capacity using PAM fluorometry, and quantifying chlorophyll a content in three pigmented parasites, showed different host nutrient dependencies. Rhodophyllis parasitica and Vertebrata aterrimophila are not able to photosynthesize and are fully dependent on host nutrients. Pterocladiophila hemisphaerica is able to photosynthesize independently, even though it has a reduced non-photosynthetic plastid genome, and therefore is only partially dependent on its host. This study advances our current understanding of red algal parasites and highlights many possibilities for future research including genome evolution and understanding parasite diversity.</p>

Fourth addendum to the synoptic review of red algal genera

2019 ◽  
Vol 62 (4) ◽  
pp. 355-367 ◽  
Author(s):  
Craig W. Schneider ◽  
Michael J. Wynne
Keyword(s):  
New Taxa ◽  
Red Algae ◽  
New Genera ◽  
Half Century ◽  
Hierarchical Framework ◽  
The Third ◽  
The Past ◽  
Red Algal ◽  
Molecular Sequencing

Abstract The fourth addendum to Schneider and Wynne’s 2007 “A synoptic review of the classification of red algal genera a half century after Kylin’s 1956 ‘Die Gattungen der Rhodophyceen’” is presented, covering the names of genus- and higher-level taxa added or modified since our third addendum (Bot. Mar. 59: 397–404). Since that synopsis, we added 21 new genera in a first addendum, 27 in the second, and 40 in the third, demonstrating the increasing amount of genetic work over more than a decade. In this fourth addendum, we add 58 new genera to the list of red algae as well as many new taxa in the hierarchical framework over the past 3 years. Based upon molecular sequencing, other genera reinstated from synonymy studies are included.

scholarly journals Structural Characterization of Cuta- and Tusavirus: Insight into Protoparvoviruses Capsid Morphology

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 653
Author(s):  
Mario Mietzsch ◽  
Robert McKenna ◽  
Elina Väisänen ◽  
Jennifer C. Yu ◽  
Maria Ilyas ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Structure Evolution ◽  
Cellular Interactions ◽  
Human Pathogens ◽  
Cryo Electron Microscopy ◽  
Cellular Entry ◽  
Surface Loops ◽  
Antigenic Reactivity ◽  
Insight Into

Several members of the Protoparvovirus genus, capable of infecting humans, have been recently discovered, including cutavirus (CuV) and tusavirus (TuV). To begin the characterization of these viruses, we have used cryo-electron microscopy and image reconstruction to determine their capsid structures to ~2.9 Å resolution, and glycan array and cell-based assays to identify glycans utilized for cellular entry. Structural comparisons show that the CuV and TuV capsids share common features with other parvoviruses, including an eight-stranded anti-parallel β-barrel, depressions at the icosahedral 2-fold and surrounding the 5-fold axes, and a channel at the 5-fold axes. However, the viruses exhibit significant topological differences in their viral protein surface loops. These result in three separated 3-fold protrusions, similar to the bufaviruses also infecting humans, suggesting a host-driven structure evolution. The surface loops contain residues involved in receptor binding, cellular trafficking, and antigenic reactivity in other parvoviruses. In addition, terminal sialic acid was identified as the glycan potentially utilized by both CuV and TuV for cellular entry, with TuV showing additional recognition of poly-sialic acid and sialylated Lewis X (sLeXLeXLeX) motifs reported to be upregulated in neurotropic and cancer cells, respectively. These structures provide a platform for annotating the cellular interactions of these human pathogens.

Marine red algae (Rhodophyta) of economic use in the algal drifts from the Yucatan Peninsula, Mexico

Phytotaxa ◽  
2019 ◽  
Vol 387 (3) ◽  
pp. 219 ◽  
Author(s):  
MARÍA LUISA NÚÑEZ RESENDIZ ◽  
KURT M. DRECKMANN ◽  
ABEL SENTÍES ◽  
MICHAEL J. WYNNE ◽  
HILDA LEÓN TEJERA
Keyword(s):  
Red Algae ◽  
New Records ◽  
Yucatan Peninsula ◽  
First Record ◽  
Economic Importance ◽  
Raw Material ◽  
Western Atlantic ◽  
Yucatán Peninsula ◽  
Red Algal ◽  
Economic Use

Red algae are the most conspicuous component in algal drifts that periodically arrive on the coasts of the Yucatan Peninsula. Given the presence of agars and carrageenans in their cell wall and the synthesis of secondary metabolites that act as antitumors or antioxidants, most of these species are highly valued in the international market. However, in this region of Mexico they are not used but represent a problem of waste from beaches. Our aim was to determine the composition of marine red algae of economic use in the algal drifts of the Yucatan Peninsula, providing brief descriptions, photographs that facilitate their identification and possible explanations for their causes and routes of origin. 13 samplings were carried out at 14 sites, collecting fresh and complete thalli from which the species of economic importance were described. 24 species distributed in six orders and seven families were identified. The most abundant families for both the number of species and the amount of biomass were Gracilariaceae (10 species), Rhodomelaceae (6 species) and Solieriaceae (3 species). The localities with the greatest diversity and biomass were those belonging to Campeche: Sabancuy (11 species), Punta Xen (14 species), Tortuga Bay (13 species) and Playa Bonita (13 species). From the present study we contributed six new records endemic to Campeche, including the first record of the genus Codiophyllum for the Western Atlantic Ocean. Our data on diversity, biomass, periodicity and growth rates of red algal drifts allow us to suggest that the Campeche and Yucatan drifts are a sustainable source of raw material.

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