scholarly journals Horizontal Transmission of the Heritable Protective Endosymbiont Hamiltonella defensa Depends on Titre and Haplotype

2021 ◽  
Vol 11 ◽  
Author(s):  
Heidi Kaech ◽  
Christoph Vorburger
Keyword(s):  
Natural Enemies ◽  
Horizontal Transmission ◽  
Aphis Fabae ◽  
Parasitoid Wasps ◽  
High Cell ◽  
Transmission Success ◽  
Hamiltonella Defensa ◽  
Cell Densities ◽  
Haplotype 1 ◽  
Secondary Endosymbiont

Secondary endosymbionts of aphids have an important ecological and evolutionary impact on their host, as they provide resistance to natural enemies but also reduce the host’s lifespan and reproduction. While secondary symbionts of aphids are faithfully transmitted from mother to offspring, they also have some capacity to be transmitted horizontally between aphids. Here we explore whether 11 isolates from 3 haplotypes of the secondary endosymbiont Hamiltonella defensa differ in their capacity for horizontal transmission. These isolates vary in the protection they provide against parasitoid wasps as well as the costs they inflict on their host, Aphis fabae. We simulated natural horizontal transmission through parasitoid wasps by stabbing aphids with a thin needle and assessed horizontal transmission success of the isolates from one shared donor clone into three different recipient clones. Specifically, we asked whether potentially costly isolates reaching high cell densities in aphid hosts are more readily transmitted through this route. This hypothesis was only partially supported. While transmissibility increased with titre for isolates from two haplotypes, isolates of the H. defensa haplotype 1 were transmitted with greater frequency than isolates of other haplotypes with comparable titres. Thus, it is not sufficient to be merely frequent—endosymbionts might have to evolve specific adaptations to transmit effectively between hosts.

scholarly journals Horizontal Transfer of Bacterial Cytolethal Distending Toxin B Genes to Insects

2019 ◽  
Vol 36 (10) ◽  
pp. 2105-2110 ◽  
Author(s):  
Kirsten I Verster ◽  
Jennifer H Wisecaver ◽  
Marianthi Karageorgi ◽  
Rebecca P Duncan ◽  
Andrew D Gloss ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Natural Enemies ◽  
Larval Stage ◽  
Horizontal Transfer ◽  
Parasitoid Wasps ◽  
Cytolethal Distending Toxin ◽  
Toxin B ◽  
Genes Encoding ◽  
Hamiltonella Defensa

Abstract Horizontal gene transfer events have played a major role in the evolution of microbial species, but their importance in animals is less clear. Here, we report horizontal gene transfer of cytolethal distending toxin B (cdtB), prokaryotic genes encoding eukaryote-targeting DNase I toxins, into the genomes of vinegar flies (Diptera: Drosophilidae) and aphids (Hemiptera: Aphididae). We found insect-encoded cdtB genes are most closely related to orthologs from bacteriophage that infect Candidatus Hamiltonella defensa, a bacterial mutualistic symbiont of aphids that confers resistance to parasitoid wasps. In drosophilids, cdtB orthologs are highly expressed during the parasitoid-prone larval stage and encode a protein with ancestral DNase activity. We show that cdtB has been domesticated by diverse insects and hypothesize that it functions in defense against their natural enemies.

scholarly journals Phage loss and the breakdown of a defensive symbiosis in aphids

2013 ◽  
Vol 280 (1751) ◽  
pp. 20122103 ◽  
Author(s):  
S. R. Weldon ◽  
M. R. Strand ◽  
K. M. Oliver
Keyword(s):  
Acyrthosiphon Pisum ◽  
Bacterial Symbiont ◽  
Parasitoid Wasps ◽  
Bacterial Symbionts ◽  
Delayed Onset ◽  
Lower Weight ◽  
Terrestrial Arthropods ◽  
Defensive Symbiosis ◽  
Hamiltonella Defensa ◽  
Secondary Endosymbiont

Terrestrial arthropods are often infected with heritable bacterial symbionts, which may themselves be infected by bacteriophages. However, what role, if any, bacteriophages play in the regulation and maintenance of insect–bacteria symbioses is largely unknown. Infection of the aphid Acyrthosiphon pisum by the bacterial symbiont Hamiltonella defensa confers protection against parasitoid wasps, but only when H. defensa is itself infected by the phage A. pisum secondary endosymbiont (APSE). Here, we use a controlled genetic background and correlation-based assays to show that loss of APSE is associated with up to sevenfold increases in the intra-aphid abundance of H. defensa . APSE loss is also associated with severe deleterious effects on aphid fitness: aphids infected with H. defensa lacking APSE have a significantly delayed onset of reproduction, lower weight at adulthood and half as many total offspring as aphids infected with phage-harbouring H. defensa , indicating that phage loss can rapidly lead to the breakdown of the defensive symbiosis. Our results overall indicate that bacteriophages play critical roles in both aphid defence and the maintenance of heritable symbiosis.

scholarly journals Parasitoids as vectors of facultative bacterial endosymbionts in aphids

2012 ◽  
Vol 8 (4) ◽  
pp. 613-615 ◽  
Author(s):  
Lukas Gehrer ◽  
Christoph Vorburger
Keyword(s):  
Horizontal Transmission ◽  
Aphis Fabae ◽  
Diagnostic Pcr ◽  
Sexual Generation ◽  
Bacterial Endosymbionts ◽  
Symbiont Transmission ◽  
Hamiltonella Defensa ◽  
The Many ◽  
First Time ◽  
Male To Female

Heritable bacterial endosymbionts play an important role in aphid ecology. Sequence-based evidence suggests that facultative symbionts such as Hamiltonella defensa or Regiella insecticola also undergo horizontal transmission. Other than through male-to-female transfer during the sexual generation in autumn, the routes by which this occurs remain largely unknown. Here, we tested if parasitoids or ectoparasitic mites can act as vectors for horizontal transfer of facultative symbionts. Using symbiont-specific primers for diagnostic PCR, we demonstrate for the first time, to our knowledge, that parasitoids can indeed transfer H. defensa and R. insecticola by sequentially stabbing infected and uninfected individuals of their host, Aphis fabae , establishing new, heritable infections. Thus, a natural route of horizontal symbiont transmission is also available during the many clonal generations of the aphid life cycle. No transmissions by ectoparasitic mites were observed, nor did parasitoids that emerged from symbiont-infected aphids transfer any symbionts in our experiments.

scholarly journals Cheaper is not always worse: strongly protective isolates of a defensive symbiont are less costly to the aphid host

2015 ◽  
Vol 282 (1799) ◽  
pp. 20142333 ◽  
Author(s):  
Luis Cayetano ◽  
Lukas Rothacher ◽  
Jean-Christophe Simon ◽  
Christoph Vorburger
Keyword(s):  
Cost Benefit ◽  
Aphis Fabae ◽  
Parasitoid Wasps ◽  
Strain Variation ◽  
Trade Off ◽  
Black Bean ◽  
Defensive Symbiosis ◽  
Hamiltonella Defensa ◽  
The Cost ◽  
Aphid Host

Defences against parasites are typically associated with costs to the host that contribute to the maintenance of variation in resistance. This also applies to the defence provided by the facultative bacterial endosymbiont Hamiltonella defensa, which protects its aphid hosts against parasitoid wasps while imposing life-history costs. To investigate the cost–benefit relationship within protected hosts, we introduced multiple isolates of H. defensa to the same genetic backgrounds of black bean aphids, Aphis fabae , and we quantified the protection against their parasitoid Lysiphlebus fabarum as well as the costs to the host (reduced lifespan and reproduction) in the absence of parasitoids. Surprisingly, we observed the opposite of a trade-off. Strongly protective isolates of H. defensa reduced lifespan and lifetime reproduction of unparasitized aphids to a lesser extent than weakly protective isolates. This finding has important implications for the evolution of defensive symbiosis and highlights the need for a better understanding of how strain variation in protective symbionts is maintained.

scholarly journals Triple RNA-Seq characterizes aphid gene expression in response to infection with unequally virulent strains of the endosymbiont Hamiltonella defensa

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Heidi Kaech ◽  
Alice B. Dennis ◽  
Christoph Vorburger
Keyword(s):  
Gene Expression ◽  
Nutrient Sensing ◽  
Aphis Fabae ◽  
Rna Seq ◽  
Buchnera Aphidicola ◽  
Virulent Strains ◽  
Hamiltonella Defensa ◽  
Different Strains ◽  
And Oxidative Stress ◽  
Secondary Endosymbiont

Abstract Background Secondary endosymbionts of aphids provide benefits to their hosts, but also impose costs such as reduced lifespan and reproductive output. The aphid Aphis fabae is host to different strains of the secondary endosymbiont Hamiltonella defensa, which encode different putative toxins. These strains have very different phenotypes: They reach different densities in the host, and the costs and benefits (protection against parasitoid wasps) they confer to the host vary strongly. Results We used RNA-Seq to generate hypotheses on why four of these strains inflict such different costs to A. fabae. We found different H. defensa strains to cause strain-specific changes in aphid gene expression, but little effect of H. defensa on gene expression of the primary endosymbiont, Buchnera aphidicola. The highly costly and over-replicating H. defensa strain H85 was associated with strongly reduced aphid expression of hemocytin, a marker of hemocytes in Drosophila. The closely related strain H15 was associated with downregulation of ubiquitin-related modifier 1, which is related to nutrient-sensing and oxidative stress in other organisms. Strain H402 was associated with strong differential regulation of a set of hypothetical proteins, the majority of which were only differentially regulated in presence of H402. Conclusions Overall, our results suggest that costs of different strains of H. defensa are likely caused by different mechanisms, and that these costs are imposed by interacting with the host rather than the host’s obligatory endosymbiont B. aphidicola.

Metabolism of hybridoma cells and antibody secretion at high cell densities in dialysis tubing

1991 ◽  
Vol 13 (11) ◽  
pp. 873-881 ◽  
Author(s):  
Claudia Käsehagen ◽  
Fritjof Linz ◽  
Gerlinde Kretzmer ◽  
Thomas Scheper ◽  
Karl Schügerl
Keyword(s):  
Hybridoma Cells ◽  
High Cell ◽  
Dialysis Tubing ◽  
Cell Densities ◽  
Antibody Secretion

Effects of the Ant, Lasius niger (L.), on the Behaviour and Reproduction of the Black Bean Aphid, Aphis fabae Scop

1958 ◽  
Vol 49 (4) ◽  
pp. 701-714 ◽  
Author(s):  
C. J. Banks
Keyword(s):  
Natural Enemies ◽  
Plant Tissue ◽  
Food Supply ◽  
Aphis Fabae ◽  
Lasius Niger ◽  
Average Difference ◽  
Young Plant ◽  
Black Bean ◽  
Bean Plants ◽  
Aphid Populations

SummaryCage experiments confirmed that, in the absence of natural enemies, populations of Aphis fabae Scop., attended on bean plants (Vicia faba) by the ant, Lasius niger (L.), multiply more rapidly than otherwise similar but ant-free populations. The average difference in numbers recorded, was about one-third, the maximum being 70 per cent. No doubling or trebling of aphid numbers as claimed by an earlier worker was ever recorded.When the Aphids are attended by ants, their excretion behaviour alters and the normal dispersal of the apterae from the young apical growth of bean plants is considerably delayed.No significant differences were found between the numbers of nymphs produced by individual Aphids from ant-visited and ant-free plants, respectively, living on leaves of the same age; but the numbers were significantly affected by the age of the leaf or part of the plant on which the Aphids had developed or were then feeding.It is suggested that ant-attended aphid populations multiply more rapidly because most of the Aphids feed for a much longer time on young plant tissue where, presumably, their food supply is more nutritious.

scholarly journals Regulation of Plant Mineral Nutrition by Signal Molecules

2021 ◽  
Vol 9 (4) ◽  
pp. 774
Author(s):  
Vipin Chandra Kalia ◽  
Chunjie Gong ◽  
Sanjay K. S. Patel ◽  
Jung-Kul Lee
Keyword(s):  
Signal Molecules ◽  
Gram Negative Bacteria ◽  
Human Beings ◽  
High Cell ◽  
Specific Chemical ◽  
Gram Negative ◽  
Plant Mineral Nutrition ◽  
Recent Developments ◽  
Cell Densities ◽  
Metabolic Activities

Microbes operate their metabolic activities at a unicellular level. However, it has been revealed that a few metabolic activities only prove beneficial to microbes if operated at high cell densities. These cell density-dependent activities termed quorum sensing (QS) operate through specific chemical signals. In Gram-negative bacteria, the most widely reported QS signals are acylhomoserine lactones. In contrast, a novel QS-like system has been elucidated, regulating communication between microbes and plants through strigolactones. These systems regulate bioprocesses, which affect the health of plants, animals, and human beings. This mini-review presents recent developments in the QS and QS-like signal molecules in promoting plant health.

scholarly journals High Productivity Ethanol Fermentation of Glucose & Xylose Using Membrane Assisted Continuous Cell Recycle

2021 ◽  
pp. 8-19
Author(s):  
Gautam Degweker ◽  
Arvind Lali
Keyword(s):  
Ethanol Fermentation ◽  
Ethanol Yield ◽  
Continuous Fermentation ◽  
Cost Effective ◽  
High Yield ◽  
High Cell ◽  
Cell Recycle ◽  
High Productivity ◽  
Ethanol Yields ◽  
Cell Densities

Rapid and high yield conversion of xylose to ethanol remains a signi cant bottleneck in the cost-effective production of ethanol using mixed sugars derived from lignocellulosic biomass (LBM). The present study attempts to circumvent this by separate continuous fermentation of glucose and xylose using high cell densities of a Saccharomyces cerevisiae mutant (ICT-1) and a Scheffersomyces stipitis mutant (M1CD), respectively with the help of external micro ltration membrane assisted cell recycle. Different cell densities and aeration rates for xylose fermentation were studied for optimizing continuous fermentation. Consistent high ethanol yields and productivities of 0.46 g/g and 5.19 g/L/h with glucose; and 0.38 g/g and 1.62 g/L/h with xylose; were achieved in simple media. This provided an average ethanol yield of 0.44 g/g on combined sugars, and average productivity of 3.4 g/L/h which is higher than typical molasses-based batch ethanol fermentation. The study thus highlights the potential of high cell density recycle strategy as an effective approach for separate ethanol fermentation of LBM derived sugars.

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