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Сергеев, В. Н.; Герасименко, Л. М.; Zavarzin, G. A.

doi:10.1023/a:1021415503436

Cited by 62 publications

(11 citation statements)

References 40 publications

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“…While most of the giant viruses, such as cedratvirus, marseilleviruses, mollivirus, pandoraviruses, mimivirus, faustovirus and kaumoebavirus, are known to be able to replicate only in a single amoeba genus, tupanvirus is able to replicate in Acanthamoeba spp., Vermoameba vermiformis , Dysctiostelium discoideum and Willartia magna 1,5–9,27,28 . The generalist profile displayed by tupanviruses may be related to the extreme aquatic environments where they were isolated (high salinity, pH and depths); within inhospitable environments there is a lower species richness and abundance, meaning there are more hosts available and a better chance of a future infection 29 . In this way, bunch formation induced by tupanvirus may be important to the recruitment of cells, improving the chances of viral progeny to find a new host cell that may be scarce in those environments.…”

Section: Resultsmentioning

confidence: 99%

Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination

Oliveira

Silva

Leão

et al. 2019

Sci Rep

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The discovery of giant viruses in the last years has fascinated the scientific community due to virus particles size and genome complexity. Among such fantastic discoveries, we have recently described tupanviruses, which particles present a long tail, and has a genome that contains the most complete set of translation-related genes ever reported in the known virosphere. Here we describe a new kind of virus-host interaction involving tupanvirus. We observed that tupanvirus-infected amoebas were induced to aggregate with uninfected cells, promoting viral dissemination and forming giant host cell bunches. Even after mechanical breakdown of bunches, amoebas reaggregated within a few minutes. This remarkable interaction between infected and uninfected cells seems to be promoted by the expression of a mannose receptor gene. Our investigations demonstrate that the pre-treatment of amoebas with free mannose inhibits the formation of bunches, in a concentration-dependent manner, suggesting that amoebal-bunch formation correlates with mannose receptor gene expression. Finally, our data suggest that bunch-forming cells are able to interact with uninfected cells promoting the dissemination and increase of tupanvirus progeny.

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Section: Resultsmentioning

confidence: 99%

Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination

Oliveira

Silva

Leão

et al. 2019

Sci Rep

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“…The motility of filamentous communities is most commonly inferred to reflect migration during diurnal cycles [6,11] in response to chemical gradients and changes in light quality and quantity [11], or with mat accretion, where trichomes naturally abandon their sheaths to form new ones at the mat surface [112]. Once the sheaths are empty, they are no longer maintained and are thus more susceptible to taphonomic alteration [109,113]. The general absence of trichome preservation, combined with limited evidence for the structural decomposition of cyanobacterial sheaths, suggests that the process of silicification may play a role in the preservation of filamentous communities.…”

Section: Mat Fabrics and Implications For Silicificationmentioning

confidence: 99%

The Taphonomy of Proterozoic Microbial Mats and Implications for Early Diagenetic Silicification

et al. 2019

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The complex nature of growth and decomposition in microbial mats results in a broad range of microbial preservation. Such taphonomic variability complicates both the description of microbial elements preserved within geologic materials and the potential interpretation of microbial biomarkers. This study uses a taphonomic assessment to explore the preservation of different microbial components within silicified microbial mats of the late Mesoproterozoic (~1.0 Ga) Angmaat Formation, Bylot Supergroup, Baffin Island. The Angmaat Formation consists of unmetamorphosed and essentially undeformed strata that represent intertidal to supratidal deposition within an evaporative microbial flat. Early diagenetic silicification preserved microbial communities across a range of environments, from those episodically exposed to persistently submerged. Here, we present the development of a new methodology involving the use of high-resolution image mosaics to investigate the taphonomy of microfossils preserved in these mats. A taphonomic grade is assigned using a modified classification that accounts for both the taphonomic preservation state (good, fair, poor) of individual microfossils, as well as the degree of compaction of the overall mat. We show that although various taphonomic states occur within each of the silicified mats, the overall taphonomic assessment differentiates between well-preserved mats that are interpreted to have been silicified during active growth, to highly degraded and compacted mats that are interpreted to represent preservation during later stages of biological decomposition. These data indicate that even small changes in the timing of silicification may have substantial implications on our identification of microbial biomarkers and, therefore, our interpretation of early Earth ecosystems.

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“…Recent determination of the genetic basis for saxitoxin (STX) has revealed that the STX gene clusters involved in the production of this toxin appear to have been present early in the divergence of the Nostocales, at least 2100 million years ago [42]. The oldest fossils of filamentous akinete-forming cyanobacteria have been dated to, between, 1600–2000 million years of age [45]. Given that most of the cyanobacteria, which produce CYN form akinetes, like MC and STX, it is likely that the genes responsible for CYN production were present in their ancient ancestor, which predates the divergence of metazoans which occurred approximately 1576 million years ago [43].…”

Section: Exploring the Evidencementioning

confidence: 99%

Interpreting the Possible Ecological Role(s) of Cyanotoxins: Compounds for Competitive Advantage and/or Physiological Aide?

2013

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To date, most research on freshwater cyanotoxin(s) has focused on understanding the dynamics of toxin production and decomposition, as well as evaluating the environmental conditions that trigger toxin production, all with the objective of informing management strategies and options for risk reduction. Comparatively few research studies have considered how this information can be used to understand the broader ecological role of cyanotoxin(s), and the possible applications of this knowledge to the management of toxic blooms. This paper explores the ecological, toxicological, and genetic evidence for cyanotoxin production in natural environments. The possible evolutionary advantages of toxin production are grouped into two main themes: That of “competitive advantage” or “physiological aide”. The first grouping illustrates how compounds produced by cyanobacteria may have originated from the need for a cellular defence mechanism, in response to grazing pressure and/or resource competition. The second grouping considers the contribution that secondary metabolites make to improved cellular physiology, through benefits to homeostasis, photosynthetic efficiencies, and accelerated growth rates. The discussion also includes other factors in the debate about possible evolutionary roles for toxins, such as different modes of exposures and effects on non-target (i.e., non-competitive) species. The paper demonstrates that complex and multiple factors are at play in driving evolutionary processes in aquatic environments. This information may provide a fresh perspective on managing toxic blooms, including the need to use a “systems approach” to understand how physico-chemical conditions, as well biological stressors, interact to trigger toxin production.

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Cited by 62 publications

References 40 publications

Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination

Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination

The Taphonomy of Proterozoic Microbial Mats and Implications for Early Diagenetic Silicification

Interpreting the Possible Ecological Role(s) of Cyanotoxins: Compounds for Competitive Advantage and/or Physiological Aide?

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