Investigation of the red algal parasites Rhodophyllis parasitica sp. nov. and Pterocladiophila hemisphaerica from New Zealand

Red algal parasites are common within red algae and most parasites are closely related to their host. Red algal parasites can switch hosts and their development is unique. Red algal parasites are poorly known in New Zealand. There are only four parasites described in New Zealand and those are based on morphological characteristics. This thesis focuses on the two red algal parasites Rhodophyllis parasitica sp. nov. and Pterocladiophila hemisphaerica from New Zealand. First, development and phylogeny and distribution of an undescribed red algal parasite growing on Rhodophyllis membranacea was investigated. Microscopy, molecular markers (ITS2, cox1, cox2-3 spacer) and phylogenetic analysis, and herbarium sampling were used to address these questions. The parasite, described as Rhodophyllis parasitica sp. nov. shows a close relationship of all genomes to Rhodophyllis membranacea, which suggests that the parasite evolved from its hosts. The parasite is widely distributed throughout New Zealand. The second parasite, Pterocladiophila hemisphaerica was grouped taxonomically, based on morphology, in the order Gracilariales and parasitizes Pterocladia lucida in the order Gelidiales. Molecular marker were used to reveal the relationship of Pterocladiophila hemisphaerica to its host: if the parasite is grouped in the Gracilariales or the Gelidiales; if host switches might have occurred; and if atp8 is present in the parasite. Nuclear DNA (SSU rRNA, LSU rRNA), mitochondrial (cox1) and plastid regions (rbcL-rbcS spacer) from the parasite were sequenced and phylogenetic analysis performed. New primer were designed to amplify atp8 and genetic analysis performed. Pterocladiophila hemisphaerica evolved in the Florideophytes but neither in the Gracilariales or Gelidiales and the parasite possibly switched hosts at least two times, which was shown by three different origins of chloroplast, mitochondria and nuclear DNA. Atp8 in the parasite is present but probably a pseudogene. Rhodophyllis parasitica sp. nov. is the first described red algal parasite species in New Zealand in 55 years and Pterocladiophila hemisphaerica is the first parasite with organelles and nuclei with different histories of origin

Gp130-Dependent Release of Acute Phase Proteins Is Linked to the Activation of Innate Immune Signaling Pathways

Background: Elevated levels of acute phase proteins (APP) are often found in patients with cardiovascular diseases. In a previous study, we demonstrated the importance of the IL-6-gp130 axis-as a key regulator of inflammatory acute phase signaling in hepatocytes-for the development of atherosclerosis. Background/Principal Findings: Gp130-dependent gene expression was analyzed in a previously established hepatocytespecific gp130 knockout mouse model. We performed whole transcriptome analysis in isolated hepatocytes to measure tissue specific responses after proinflammatory stimulus with IL-6 across different time points. Our analyses revealed an unexpected small gene cluster that requires IL-6 stimulus for early activation. Several of the genes in this cluster are involved in different cell defense mechanisms. Thus, stressors that trigger both general stress and inflammatory responses lead to activation of a stereotypic innate cellular defense response. Furthermore, we identified a potential biomarker Lipocalin (LCN) 2 for the gp130 dependent early inflammatory response. Conclusions/Significance: Our findings suggest a complex network of tightly linked genes involved in the early activatio

The Emergence of Emotions

Emotion is conscious experience. It is the affective aspect of consciousness. Emotion arises from sensory stimulation and is typically accompanied by physiological and behavioral changes in the body. Hence an emotion is a complex reaction pattern consisting of three components: a physiological component, a behavioral component, and an experiential (conscious) component. The reactions making up an emotion determine what the emotion will be recognized as. Three processes are involved in generating an emotion: (1) identification of the emotional significance of a sensory stimulus, (2) production of an affective state (emotion), and (3) regulation of the affective state. Two opposing systems in the brain (the reward and punishment systems) establish an affective value or valence (stimulus-reinforcement association) for sensory stimulation. This is process (1), the first step in the generation of an emotion. Development of stimulus-reinforcement associations (affective valence) serves as the basis for emotion expression (process 2), conditioned emotion learning acquisition and expression, memory consolidation, reinforcement-expectations, decision-making, coping responses, and social behavior. The amygdala is critical for the representation of stimulus-reinforcement associations (both reward and punishment-based) for these functions. Three distinct and separate architectural and functional areas of the prefrontal cortex (dorsolateral prefrontal cortex, orbitofrontal cortex, anterior cingulate cortex) are involved in the regulation of emotion (process 3). The regulation of emotion by the prefrontal cortex consists of a positive feedback interaction between the prefrontal cortex and the inferior parietal cortex resulting in the nonlinear emergence of emotion. This positive feedback and nonlinear emergence represents a type of working memory (focal attention) by which perception is reorganized and rerepresented, becoming explicit, functional, and conscious. The explicit emotion states arising may be involved in the production of voluntary new or novel intentional (adaptive) behavior, especially social behavior

Characterizing Prostate Cancer Risk Through Multi-Ancestry Genome-Wide Discovery of 187 Novel Risk Variants

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups

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

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

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

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

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

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

Three new red algal parasites from New Zealand: Cladhymenia oblongifoliaphila sp. nov. (Rhodomelaceae), Phycodrys novae-zelandiaephila sp. nov. (Delesseriaceae) and Judithia parasitica sp. nov. (Kallymeniaceae)

2018 International Phycological Society There are over 120 species of red algal parasites (Florideophyceae) but they are often overlooked due to their small size and patchy distribution. Red algal parasites have mostly been described as independent genera but recent phylogenetic studies have shown that parasites are related to free-living relatives, often their hosts, and have been named in these genera to maintain monophyly. We investigated the morphology, distribution and phylogeny, using diverse molecular markers (mitochondrial, nuclear, plastid), of three new red algal parasites in New Zealand. We describe the parasites using morphological and anatomical observations and estimate their distribution by surveying herbarium vouchers. Analyses of reproductive structures and molecular phylogenies indicate that the closest relative of the parasite Phycodrys novae-zelandiaephila sp. nov. is its host, Phycodrys novae-zelandiae. Based on nuclear and mitochondrial markers, the closest relative of the parasite Cladhymenia oblongifoliaphila sp. nov. is its host Cladhymenia oblongifolia but plastid markers group it with Cladhymenia lyallii, suggesting that this species was a past host and the source of parasite plastids. The parasite Judithia parasitica sp. nov. groups with Judithia delicatissima but infects Blastophyllis spp., suggesting that this parasite evolved as a free-living or parasitic Judithia species, and host switching may have occurred. This study adds to our knowledge of New Zealand red algal parasites and highlights contrasting patterns of host–parasite relationships

Development of the red algal parasite Vertebrata aterrimophila sp. nov. (Rhodomelaceae, Ceramiales) from New Zealand

© 2019, © 2019 British Phycological Society. Parasitic red algae grow only on other red algae and have over 120 described species. Developmental studies in red algal parasites are few, although they have shown that secondary pit connections formed between parasite and host and proposed that this was an important process in successful parasitism. Furthermore, it was recorded that the transfer of parasite nuclei by these secondary pit connections led to different host cell effects. We used developmental studies to reconstruct early stages and any host cell effects of a parasite on Vertebrata aterrima. A mitochondrial marker (cox1) and morphological observations (light and fluorescence microscopy) were used to describe this new red algal parasite as Vertebrata aterrimophila sp. nov. Early developmental stages show that a parasite spore connects via secondary pit connections with a pericentral host cell after cuticle penetration. Developmental observations revealed a unique connection cell that grows into a ‘trunk-like’ structure. Host cell transformation after infection by the parasite included apparent increases in both carbohydrate concentrations and nuclear size, as well as structural changes. Analyses of molecular phylogenies and reproductive structures indicated that the closest relative of V. aterrimophila is its host, V. aterrima. Our study shows a novel developmental parasite stage (‘trunk-like’ cell) and highlights the need for further developmental studies to investigate the range of developmental patterns and host effects in parasitic red algae

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

© 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