scholarly journals Ploidy dynamics in aphid host cells harboring bacterial symbionts

2021 ◽  
Author(s):  
Tomonari Nozaki ◽  
Shuji Shigenobu
Keyword(s):  
Acyrthosiphon Pisum ◽  
Biological Significance ◽  
Large Cell ◽  
Host Cells ◽  
Bacterial Symbionts ◽  
Buchnera Aphidicola ◽  
Ploidy Levels ◽  
Future Studies ◽  
Functional Roles ◽  
Aphid Host

AbstractAphids have evolved bacteriocytes or symbiotic host cells that harbor the obligate mutualistic bacterium Buchnera aphidicola. Because of the large cell size (approximately 100 μm in diameter) of bacteriocytes and their pivotal role in nutritional symbiosis, researchers have considered that these cells are highly polyploid and assumed that bacteriocyte polyploidy may be essential for the symbiotic relationship between the aphid and the bacterium. However, little is known about the ploidy levels and dynamics of aphid bacteriocytes. Here, we quantitatively analyzed the ploidy levels in the bacteriocytes of the pea-aphid Acyrthosiphon pisum. Image-based fluorometry revealed the hyper polyploidy of the bacteriocytes ranging from 16- to 256-ploidy throughout the lifecycle. Bacteriocytes of adult parthenogenetic viviparous females were mainly 64-128C DNA levels, while those of sexual morphs (oviparous females and males) were consisted of 64C, and 32-64C cells, respectively. During post-embryonic development of viviparous females, the ploidy level of bacteriocytes increased substantially, from 16-32C at birth to 128-256C in actively reproducing adults. These results suggest that the ploidy levels are dynamically regulated among phenotypes and during development. Our comprehensive and quantitative data provides a foundation for future studies to understand the functional roles and biological significance of the polyploidy of insect bacteriocytes.

scholarly journals Matching the supply of bacterial nutrients to the nutritional demand of the animal host

2014 ◽  
Vol 281 (1791) ◽  
pp. 20141163 ◽  
Author(s):  
Calum W. Russell ◽  
Anton Poliakov ◽  
Meena Haribal ◽  
Georg Jander ◽  
Klaas J. van Wijk ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Acyrthosiphon Pisum ◽  
Feedback Inhibition ◽  
Essential Amino Acids ◽  
Host Cells ◽  
Host Proteins ◽  
Buchnera Aphidicola ◽  
Symbiotic Microorganisms ◽  
Precursor Supply ◽  
Host Regulation

Various animals derive nutrients from symbiotic microorganisms with much-reduced genomes, but it is unknown whether, and how, the supply of these nutrients is regulated. Here, we demonstrate that the production of essential amino acids (EAAs) by the bacterium Buchnera aphidicola in the pea aphid Acyrthosiphon pisum is elevated when aphids are reared on diets from which that EAA are omitted, demonstrating that Buchnera scale EAA production to host demand. Quantitative proteomics of bacteriocytes (host cells bearing Buchnera ) revealed that these metabolic changes are not accompanied by significant change in Buchnera or host proteins, suggesting that EAA production is regulated post-translationally. Bacteriocytes in aphids reared on diet lacking the EAA methionine had elevated concentrations of both methionine and the precursor cystathionine, indicating that methionine production is promoted by precursor supply and is not subject to feedback inhibition by methionine. Furthermore, methionine production by isolated Buchnera increased with increasing cystathionine concentration. We propose that Buchnera metabolism is poised for EAA production at certain maximal rates, and the realized release rate is determined by precursor supply from the host. The incidence of host regulation of symbiont nutritional function via supply of key nutritional inputs in other symbioses remains to be investigated.

scholarly journals Effects of Endosymbiont Disruption on the Nutritional Dynamics of the Pea Aphid Acyrthosiphon pisum

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 161 ◽  
Author(s):  
Ning Lv ◽  
Lei Wang ◽  
Wen Sang ◽  
Chang-Zhong Liu ◽  
Bao-Li Qiu
Keyword(s):  
Energy Metabolism ◽  
Host Plants ◽  
Acyrthosiphon Pisum ◽  
Soluble Sugars ◽  
Pea Aphid ◽  
Buchnera Aphidicola ◽  
Phloem Sap ◽  
Nutritional Factors ◽  
Pea Aphids ◽  
Aphid Host

Pea aphid (Acyrthosiphon pisum) is a worldwide pest that feeds exclusively on the phloem sap of numerous host plants. It harbours a well-known primary endosymbiont Buchnera aphidicola that helps to overcome the nutritional deficiency of a plant-based diet. However, how the Buchnera contributes to the nutritional and energy metabolism of its aphid host is unclear to date. In the current study, the function of Buchnera in relation to nutritional synthesis of pea aphid was investigated by disrupting the primary endosymbiont with an antibiotic rifampicin. Our findings revealed that the disruption of Buchnera led to infertility and higher loss in body mass of aphid hosts. Body length and width were also decreased significantly compared to healthy aphids. The detection of nutrition indicated that the quantity of proteins, soluble sugars, and glycogen in aposymbiotic pea aphids increased slowly with the growth of the aphid host. In comparison, the quantities of all the nutritional factors were significantly lower than those of symbiotic pea aphids, while the quantity of total lipid and neutral fat in aposymbiotic pea aphids were distinctly higher than those of symbiotic ones. Thus, we concluded that the significant reduction of the total amount of proteins, soluble sugars, and glycogen and the significant increase of neutral fats in aposymbiotic pea aphids were due to the disruption of Buchnera, which confirmed that the function of Buchnera is irreplaceable in the pea aphid.

scholarly journals Further evidence that mechanisms of host/symbiont integration are dissimilar in the maternal versus embryonic Acyrthosiphon pisum bacteriome

EvoDevo ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Celeste R. Banfill ◽  
Alex C. C. Wilson ◽  
Hsiao-ling Lu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acyrthosiphon Pisum ◽  
Essential Amino Acids ◽  
Developmental Time ◽  
Follicular Epithelium ◽  
Future Research ◽  
Buchnera Aphidicola ◽  
Bacterial Endosymbionts ◽  
Asexual Embryogenesis

Abstract Background Host/symbiont integration is a signature of evolutionarily ancient, obligate endosymbioses. However, little is known about the cellular and developmental mechanisms of host/symbiont integration at the molecular level. Many insects possess obligate bacterial endosymbionts that provide essential nutrients. To advance understanding of the developmental and metabolic integration of hosts and endosymbionts, we track the localization of a non-essential amino acid transporter, ApNEAAT1, across asexual embryogenesis in the aphid, Acyrthosiphon pisum. Previous work in adult bacteriomes revealed that ApNEAAT1 functions to exchange non-essential amino acids at the A. pisum/Buchnera aphidicola symbiotic interface. Driven by amino acid concentration gradients, ApNEAAT1 moves proline, serine, and alanine from A. pisum to Buchnera and cysteine from Buchnera to A. pisum. Here, we test the hypothesis that ApNEAAT1 is localized to the symbiotic interface during asexual embryogenesis. Results During A. pisum asexual embryogenesis, ApNEAAT1 does not localize to the symbiotic interface. We observed ApNEAAT1 localization to the maternal follicular epithelium, the germline, and, in late-stage embryos, to anterior neural structures and insect immune cells (hemocytes). We predict that ApNEAAT1 provisions non-essential amino acids to developing oocytes and embryos, as well as to the brain and related neural structures. Additionally, ApNEAAT1 may perform roles related to host immunity. Conclusions Our work provides further evidence that the embryonic and adult bacteriomes of asexual A. pisum are not equivalent. Future research is needed to elucidate the developmental time point at which the bacteriome reaches maturity.

scholarly journals Cross-Talk between PPARs and the Partners of RXR: A Molecular Perspective

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Lap Shu Alan Chan ◽  
Richard A. Wells
Keyword(s):  
Dna Binding ◽  
Nuclear Receptors ◽  
Cross Talk ◽  
Molecular Level ◽  
Signaling Networks ◽  
Future Studies ◽  
Functional Roles ◽  
Dimerization Interface ◽  
Experimental Approaches ◽  
Nuclear Receptor Subfamily

The PPARs are integral parts of the RXR-dependent signaling networks. Many other nuclear receptor subfamily 1 members also require RXR as their obligatory heterodimerization partner and they are often co-expressed in any given tissue. Therefore, the PPARs often complete with other RXR-dependent nuclear receptors and this competition has important biological implications. Thorough understanding of this cross-talk at the molecular level is crucial to determine the detailed functional roles of the PPARs. At the level of DNA binding, most RXR heterodimers bind selectively to the well-known “DR1 to 5” DNA response elements. As a result, many heterodimers share the same DR element and must complete with each other for DNA binding. At the level of heterodimerization, the partners of RXR share the same RXR dimerization interface. As a result, individual nuclear receptors must complete with each other for RXR to form functional heterodimers. Cross-talk through DNA binding and RXR heterodimerization present challenges to the study of these nuclear receptors that cannot be adequately addressed by current experimental approaches. Novel tools, such as engineered nuclear receptors with altered dimerization properties, are currently being developed. These tools will enable future studies to dissect specific RXR heterodimers and their signaling pathways.

scholarly journals BCL-6 Protein Expression in Human Peripheral T-Cell Neoplasms Is Restricted to CD30+ Anaplastic Large-Cell Lymphomas

Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2445-2450 ◽  
Author(s):  
Antonino Carbone ◽  
Annunziata Gloghini ◽  
Gianluca Gaidano ◽  
Riccardo Dalla-Favera ◽  
Brunangelo Falini
Keyword(s):  
T Cell ◽  
Protein Expression ◽  
Lymph Nodes ◽  
Cell Lines ◽  
Biological Significance ◽  
Large Cell ◽  
Lymphoid Cells ◽  
Null Cell ◽  
The Relationship ◽  
Cell Proliferations

Abstract The expression pattern of the BCL-6 transcription factor has been assessed in normal and neoplastic B-cell populations and in Hodgkin's disease. However, little is known about BCL-6 expression and its biological significance in T-cell neoplasms. In this study, a series of 59 lymphoma samples, including 27 CD30+ anaplastic large-cell lymphomas (ALCLs), 24 other peripheral T-cell neoplasms, and 8 T-cell lymphoblastic lymphomas (T-LBLs), as well as a panel of t(2; 5)-positive lymphoma-derived human cell lines, were evaluated for BCL-6 protein expression by immunohistochemistry on frozen sections and cell smears. To define the relationship between BCL-6 protein and CD30 antigen in CD30+ ALCLs and in non-neoplastic lymph nodes, serial section immunohistochemistry and two-color staining were used in selected CD30+ ALCLs as well as in reactive lymph nodes with non-neoplastic T-cell proliferations. BCL-6 protein was expressed in 12 of 27 (45%) CD30+ ALCL cases, irrespective of their antigenic phenotypes (T-cell or null-cell type), and in the t(2; 5)-positive cell lines. In contrast, the remaining 24 peripheral T-cell neoplasms as well as the 8 T-LBLs were considered negative for BCL-6 expression. Coexpression of CD30 and BCL-6, as detected in CD30+ ALCLs, was also found in a subset of non-neoplastic lymphoid elements, namely the large lymphoid cells scattered in the interfollicular areas of reactive lymph nodes. These findings suggest that CD30+ ALCLs may represent the neoplastic transformation of extrafollicular CD30+ cells and that BCL-6 may provide an additional marker for characterizing CD30+ ALCLs.

scholarly journals Codon usage bias and tRNA over-expression in Buchnera aphidicola after aromatic amino acid nutritional stress on its host Acyrthosiphon pisum

2006 ◽  
Vol 34 (16) ◽  
pp. 4583-4592 ◽  
Author(s):  
Hubert Charles ◽  
Federica Calevro ◽  
José Vinuelas ◽  
Jean-Michel Fayard ◽  
Yvan Rahbe
Keyword(s):  
Amino Acid ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Aromatic Amino Acid ◽  
Acyrthosiphon Pisum ◽  
Nutritional Stress ◽  
Buchnera Aphidicola ◽  
Over Expression

scholarly journals Proteoglycans in host–pathogen interactions: molecular mechanisms and therapeutic implications

2010 ◽  
Vol 12 ◽  
Author(s):  
Allison H. Bartlett ◽  
Pyong Woo Park
Keyword(s):  
Cell Surface ◽  
Virulence Factors ◽  
Molecular Mechanisms ◽  
Biological Significance ◽  
Host Cells ◽  
Microbial Pathogens ◽  
Therapeutic Implications ◽  
Core Proteins

Many microbial pathogens subvert proteoglycans for their adhesion to host tissues, invasion of host cells, infection of neighbouring cells, dissemination into the systemic circulation, and evasion of host defence mechanisms. Where studied, specific virulence factors mediate these proteoglycan–pathogen interactions, which are thus thought to affect the onset, progression and outcome of infection. Proteoglycans are composites of glycosaminoglycan (GAG) chains attached covalently to specific core proteins. Proteoglycans are expressed ubiquitously on the cell surface, in intracellular compartments, and in the extracellular matrix. GAGs mediate the majority of ligand-binding activities of proteoglycans, and many microbial pathogens elaborate cell-surface and secreted factors that interact with GAGs. Some pathogens also modulate the expression and function of proteoglycans through known virulence factors. Several GAG-binding pathogens can no longer attach to and invade host cells whose GAG expression has been reduced by mutagenesis or enzymatic treatment. Furthermore, GAG antagonists have been shown to inhibit microbial attachment and host cell entry in vitro and reduce virulence in vivo. Together, these observations underscore the biological significance of proteoglycan–pathogen interactions in infectious diseases.

Facultative 'secondary' bacterial symbionts and the nutrition of the pea aphid, Acyrthosiphon pisum

2006 ◽  
Vol 31 (3) ◽  
pp. 262-269 ◽  
Author(s):  
A. E. DOUGLAS ◽  
C. L. M. J. FRANCOIS ◽  
L. B. MINTO
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Bacterial Symbionts

New cell antigens induced by viruses and their biological significance

1971 ◽  
Vol 177 (1046) ◽  
pp. 23-39 ◽  
Keyword(s):  
Host Cell ◽  
Genetic Modification ◽  
Biological Significance ◽  
Virus Genome ◽  
Host Cells ◽  
Immunological Methods ◽  
Replication Process ◽  
General Importance ◽  
Long Time ◽  
Immunological Surveillance

Nearly all virus-infected cells are found to have new antigens not present in uninfected cells. Many such antigens are concerned in virus replication, either representing components of the virions themselves or, presumably, enzymes or other materials required for the replication process. Most antigens are short-term products: the host cells are killed or soon recover from the effects of the virus. However, in some cases the production of antigens can continue for a long time, with interesting consequences. In fact, the presence of such antigens is one of the main ways in which genetic modification of host cells by viruses—which is the subject of this meeting—can be detected. The term ‘antigen’ is here used in a broad sense for any component that can be demonstrated by immunological methods, not necessarily in the host species. Those that can elicit immune responses in the host are especially interesting because they are not laboratory artefacts and may be relevant to such phenomena as immunological surveillance against tumours and auto-immunity, as discussed below. The first point that requires consideration is the way in which viruses can bring about genetic modification of host cells. These can be classified into four main groups: (1) Expression of a persisting non-integrated virus genome. (2) Expression of an integrated virus genome. (3) Depression of host cell genes. (4) Alteration of the host cell genome. Examples of each of these will be considered, although in some cases the attribution of observed phenomena into the appropriate category is uncertain. Further studies should be directed towards resolving these uncertainties, because understanding of the mechanisms involved is of general importance in relation to understanding virus carcinogenesis and possibly some aspects of autoimmunity.

scholarly journals Aphids evolved novel secreted proteins for symbiosis with bacterial endosymbiont

2013 ◽  
Vol 280 (1750) ◽  
pp. 20121952 ◽  
Author(s):  
Shuji Shigenobu ◽  
David L. Stern
Keyword(s):  
Acyrthosiphon Pisum ◽  
Developmental Time ◽  
Secreted Proteins ◽  
Buchnera Aphidicola ◽  
Orphan Genes ◽  
Specific Expression ◽  
Small Proteins ◽  
Endosymbiotic Bacteria ◽  
Host Aphid

Aphids evolved novel cells, called bacteriocytes, that differentiate specifically to harbour the obligatory mutualistic endosymbiotic bacteria Buchnera aphidicola . The genome of the host aphid Acyrthosiphon pisum contains many orphan genes that display no similarity with genes found in other sequenced organisms, prompting us to hypothesize that some of these orphan genes are related to lineage-specific traits, such as symbiosis. We conducted deep sequencing of bacteriocytes mRNA followed by whole mount in situ hybridizations of over-represented transcripts encoding aphid-specific orphan proteins. We identified a novel class of genes that encode small proteins with signal peptides, which are often cysteine-rich, that are over-represented in bacteriocytes. These genes are first expressed at a developmental time point coincident with the incorporation of symbionts strictly in the cells that contribute to the bacteriocyte and this bacteriocyte-specific expression is maintained throughout the aphid's life. The expression pattern suggests that recently evolved secretion proteins act within bacteriocytes, perhaps to mediate the symbiosis with beneficial bacterial partners, which is reminiscent of the evolution of novel cysteine-rich secreted proteins of leguminous plants that regulate nitrogen-fixing endosymbionts.

Sign in / Sign up

Export Citation Format

Share Document