Chloroviruses Lure Hosts through Long-Distance Chemical Signaling

Dunigan, David D.; Al-Sammak, Maitham Ahmed; Al-Ameeli, Zeina; Agarkova, Irina; DeLong, John P.; Etten, James L. Van

doi:10.1128/jvi.01688-18

Cited by 12 publications

(8 citation statements)

References 27 publications

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“…In this experiment, 75% of cells on average migrated towards the chemotactic stimulus showing stochastic locomotion movements with robust directionality towards the peptide (chemotaxis). All these unicellular organisms belonging to the three species here studied responded in concordance with other similar experimental observations, carried out in absence of stimuli 17 , in galvanotactic conditions 15,16 , and under a chemotactic stimulus 24 .…”

Section: Discussionsupporting

confidence: 89%

Unicellular associative conditioning: an interspecies analysis

Carrasco-Pujante

Bringas

Malaina

et al. 2020

Preprint

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The capacity to learn new systemic behaviour is a fundamental issue to understand the adaptive mechanisms involved in cellular evolution. We have recently observed, in a preliminary analysis, the emergence of conditioned behaviour in individual amoebae cells. In these experiments, cells were able to acquire new migratory conduct and remember it for long periods of their cellular cycle, forgetting it later on. Here, following a similar conceptual framework to that used by Pavlov in his experiments, we have exhaustively studied the migration trajectories of more than 2000 individual cells belonging to three different species: Amoeba proteus, Metamoeba leningradensis, and Amoeba borokensis. Fundamentally, we have analysed several properties of conditioned cells, such as the intensity of the responses, the directionality persistence, the total distance traveled, the directionality ratio, the average speed, and the persistence times. We have observed that these three species can modify the systemic response to a specific stimulus by associative conditioning. Our main analysis shows that such new behaviour is very robust and presents a similar structure of migration patterns in the three species, which was characterized by the presence of conditioning for long periods, remarkable straightness in their trajectories and strong directional persistence. Our quantitative results, compared with other studies on complex cellular responses in bacteria, protozoa, fungus-like organisms and metazoans, allow us to conclude that cellular associative conditioning might be a widespread characteristic of unicellular organisms. This finding could be essential to understand some key evolutionary principles involved in increasing the cellular adaptive fitness to microenvironments.

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Section: Discussionsupporting

confidence: 89%

Unicellular associative conditioning: an interspecies analysis

Carrasco-Pujante

Bringas

Malaina

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…In this experiment, 75% of cells on average migrated toward the chemotactic stimulus showing stochastic locomotion movements with robust directionality toward the peptide (chemotaxis). All these unicellular organisms belonging to the three species here studied responded in concordance with other similar experimental observations, carried out in absence of stimuli (De la Fuente et al, 2019b), in galvanotactic conditions (Prusch and Britton, 1987;Bray, 2000), and under a chemotactic stimulus (Dunigan et al, 2019).…”

Section: Discussionsupporting

confidence: 89%

Associative Conditioning Is a Robust Systemic Behavior in Unicellular Organisms: An Interspecies Comparison

et al. 2021

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The capacity to learn new efficient systemic behavior is a fundamental issue of contemporary biology. We have recently observed, in a preliminary analysis, the emergence of conditioned behavior in some individual amoebae cells. In these experiments, cells were able to acquire new migratory patterns and remember them for long periods of their cellular cycle, forgetting them later on. Here, following a similar conceptual framework of Pavlov’s experiments, we have exhaustively studied the migration trajectories of more than 2000 individual cells belonging to three different species: Amoeba proteus, Metamoeba leningradensis, and Amoeba borokensis. Fundamentally, we have analyzed several relevant properties of conditioned cells, such as the intensity of the responses, the directionality persistence, the total distance traveled, the directionality ratio, the average speed, and the persistence times. We have observed that cells belonging to these three species can modify the systemic response to a specific stimulus by associative conditioning. Our main analysis shows that such new behavior is very robust and presents a similar structure of migration patterns in the three species, which was characterized by the presence of conditioning for long periods, remarkable straightness in their trajectories and strong directional persistence. Our experimental and quantitative results, compared with other studies on complex cellular responses in bacteria, protozoa, fungus-like organisms and metazoans that we discus here, allow us to conclude that cellular associative conditioning might be a widespread characteristic of unicellular organisms. This new systemic behavior could be essential to understand some key principles involved in increasing the cellular adaptive fitness to microenvironments.

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“…The accumulation of infectious virions on the cell surface, which can number in the hundreds [228], could occur through random contacts between P. bursaria and chlorovirus particles as the paramecia move through the water. However, ongoing experiments indicate that the chloroviruses release a chemotactic agent that attracts P. bursaria [197]. To our knowledge this is the first example of a virus attracting its host through long-distance chemical signaling although in this example the virus is attracting the organism that is carrying the host.…”

Section: Resistance To Chlorovirus Infectionsmentioning

confidence: 92%

“…Basic proteins and divalent cations apparently play a big role in neutralizing the PBCV-1 genome [120]. As reported in the ecology section below, the chloroviruses can attract Paramecium bursaria, which harbor the zoochlorellae hosts for the viruses, with a chemo-attractive agent [197] and maybe the agent is one or more of the polyamines.…”

Section: Chlorovirus Genes and Biotechnologymentioning

confidence: 92%

Chloroviruses

Etten

Agarkova

Dunigan

2019

Viruses

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Chloroviruses are large dsDNA, plaque-forming viruses that infect certain chlorella-like green algae; the algae are normally mutualistic endosymbionts of protists and metazoans and are often referred to as zoochlorellae. The viruses are ubiquitous in inland aqueous environments throughout the world and occasionally single types reach titers of thousands of plaque-forming units per ml of native water. The viruses are icosahedral in shape with a spike structure located at one of the vertices. They contain an internal membrane that is required for infectivity. The viral genomes are 290 to 370 kb in size, which encode up to 16 tRNAs and 330 to ~415 proteins, including many not previously seen in viruses. Examples include genes encoding DNA restriction and modification enzymes, hyaluronan and chitin biosynthetic enzymes, polyamine biosynthetic enzymes, ion channel and transport proteins, and enzymes involved in the glycan synthesis of the virus major capsid glycoproteins. The proteins encoded by many of these viruses are often the smallest or among the smallest proteins of their class. Consequently, some of the viral proteins are the subject of intensive biochemical and structural investigation.

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Chloroviruses Lure Hosts through Long-Distance Chemical Signaling

Cited by 12 publications

References 27 publications

Unicellular associative conditioning: an interspecies analysis

Unicellular associative conditioning: an interspecies analysis

Associative Conditioning Is a Robust Systemic Behavior in Unicellular Organisms: An Interspecies Comparison

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