Abundance of Tn3, Tn21, and Tn501 transposase (tnpA) sequences in bacterial community DNA from marine environments

Dahlberg, Cecilia; Hermansson, Malte

doi:10.1128/aem.61.8.3051-3056.1995

Cited by 39 publications

(26 citation statements)

References 44 publications

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“…Although speculative, previously inserted Tn elements may carry the saxitoxin biosynthetic genes-and these putatively mobile genes could account for the widespread distribution of saxitoxin biosynthetic genes in evolutionarily diverse organisms (Table I). It has been estimated that 1 in l,OOO-10,000 bacteria in marine environments carry sequences derived from the Tn3 family of transposons (Dahlberg and Hermansson 1995). Similar studies with different Tn family members (e.g.…”

Section: Mutational Analysis Of Toxin Biosynthetic Genesmentioning

confidence: 92%

Marine algal toxins: Biochemistry, genetics, and molecular biology

Plumley

1997

Limnology & Oceanography

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Toxic compounds are frequently, but not universally, associated with alg,al blooms. Several dinoflagellate and diatom species are capable of toxin synthesis. Some bacteria are also capable of synthesizing at least one family of "algal" toxins. Previous work on algal toxins can be broadly grouped in four categories: observations on the variability in toxin production by single species or among strains of a species, frequently as a function of environmental growth conditions; isotope feeding studies to reveal the identity of the substrates that are precursors to the toxin compounds; the genetics of toxin production; and the pharmacological aspects of toxins. Information gleaned from these studies provides a firm foundation for launching more contemporaneous research efforts to understand the biochemistry and molecular biology of toxins. The goals are to develop an understanding of the machinery (i.e. the enzymes and the genes that encode them) required to synthesize toxins, to understand how this machinery is regulated by environmental conditions, and gain insights as to how the tox n biosynthetic genes evolved and(or) have been spread through the marine community.The production of toxic compounds is a common, but not universal, characteristic of harmful algal blooms (HABs). Surprisingly, only a few HAB toxins have been characterized and these are synthesized by only a limited number of algal species (Steidinger 1993). Toxigenic algae may, however, exert an inordinately large adverse impact on other members of the community because toxins can flow through aquatic food chains in a manner analogous to the movement of carbon or energy (Smayda 1992). Toxigenic algae thus may have significant impacts on ecosystem processes as toxins affect viability, growth, fecundity, and recruitment of a wide range of organisms.This manuscript is concerned with the biochemistry and genetics of toxin production by HAB species. Most information is for marine toxins as these have been better documented than the freshwater toxins. Saxitoxins, the causative agent of paralytic shellfish poisoning, are used as a model throughout this review as they are the best characterized marine toxin in terms of biochemistry and genetics. The physiology and ecology of the organisms that synthesize saxitoxins are also better documented than for other HAB species; this information permits a more robust interpretation of biochemical and genetic data for the saxitoxins than for other HAB toxins. Inauspiciously, very little is known about the molecular biology of HAB toxins, making this topic difficult to review. The goal in writing the molecular section was to interpret the biochemical, genetic, and physiological data in a context that would encourage and arouse others to Acknowledgments

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Section: Mutational Analysis Of Toxin Biosynthetic Genesmentioning

confidence: 92%

Marine algal toxins: Biochemistry, genetics, and molecular biology

Plumley

1997

Limnology & Oceanography

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“…Hybridisation with probes speci¢c for the region does on the one hand increase the sensitivity of detection which is often required since PCR products may not always be visible on ethidium bromide stained agarose gels. On the other hand, it con¢rms sequence similarity of the PCR product [27,45] which is needed as unrelated sequences in the community DNA might contain parts homologous to the primer sequences and therefore generate non-speci¢c amplicons. MGE-speci¢c PCR-primer systems have also been proven to be useful to analyse the presence and diversity MGE in endogenous isolates or in [30,31,43,44,46].…”

Section: Application Of Plasmid Replicon-speci¢c Primersmentioning

confidence: 99%

“…MGE-speci¢c PCR-primer systems have also been proven to be useful to analyse the presence and diversity MGE in endogenous isolates or in [30,31,43,44,46]. One of the ¢rst studies to apply MGE-speci¢c primers to total community DNA was that of Dahlberg et al [45]. A semi-nested approach was used to amplify the transposase gene of Tn3 family transposons in order to study the abundance of tnpA genes of Tn3, Tn21, and Tn501 in total community DNA from marine samples.…”

Section: Application Of Plasmid Replicon-speci¢c Primersmentioning

confidence: 99%

The prevalence and diversity of mobile genetic elements in bacterial communities of different environmental habitats: insights gained from different methodological approaches

Smalla¹

2002

FEMS Microbiology Ecology

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The pool of mobile genetic elements (MGE) in microbial communities consists of plasmids, bacteriophages and other elements that are either self-transmissible or use mobile plasmids and phages as vehicles for their dissemination. By facilitating horizontal gene exchange, the horizontal gene pool (HGP) promotes the evolution and adaptation of microbial communities. Efforts to characterise MGE from bacterial populations resident in a variety of ecological habitats have revealed a surprisingly vast and seemingly untapped diversity. MGE, conferring such selectable traits as mercury or antibiotic resistance and degradative functions, have been readily acquired from diverse microbial communities. To circumvent the need to isolate microbial hosts, polymerase chain reaction (PCR)-based detection methods have frequently been used to assess the prevalence of MGE-specific sequences resident in the 'microbial community' HGP. As studies continue to reveal novel and distinct MGE, sequencing of newly isolated MGE from diverse habitats is essential for the continued development of DNA probes, PCR primers as well as for gene array and proteomics-based approaches. This minireview highlights insight gained from different methodological approaches, biased albeit largely toward plasmids in Gram-negative bacteria, used to study the HGP of naturally occurring microbial communities from various aquatic and terrestrial habitats.

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“…The abundance of the MGE in the biosphere is enormous. Viruses are by far the most common biological entities on earth [3][4][5][6], genes of MGE, such as those encoding transposases, are among the most abundant ones in diverse environments [7][8][9], and the genomes of many multicellular organisms consist of up to 50% integrated MGE, in the case of mammals, or even up to 90% in the case of plants [10,11].…”

Section: Introductionmentioning

confidence: 99%

Stability of host-parasite systems: you must differ to coevolve

Berezovksaya

Karev²,

Katsnelson³

et al. 2018

Preprint

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Background: Genetic parasites are ubiquitous satellites of cellular life forms most of which host a variety of mobile genetic elements including transposons, plasmids and viruses. Theoretical considerations and computer simulations suggest that emergence of genetic parasites is intrinsic to evolving replicator systems.Results: Using methods of bifurcation analysis, we investigated the stability of simple models of replicator-parasite coevolution in a well-mixed environment. It is shown that the simplest imaginable system of this type, one in which the parasite evolves during the replication of the host genome through a minimal mutation that renders the genome of the emerging parasite incapable of producing the replicase but able to recognize and recruit it for its own replication, is unstable. In this model, there are only either trivial or "semi-trivial", parasite-free equilibria: an inefficient parasite is outcompeted by the host and dies off whereas an efficient one pushes the host out of existence, which leads to the collapse of the entire system. We show that stable hostparasite coevolution (a non-trivial equilibrium) is possible in a modified model where the parasite is qualitatively distinct from the host replicator in that the replication of the parasite depends solely on the availability of the host but not on the carrying capacity of the environment. Conclusions:We analytically determine the conditions for stable host-parasite coevolution in simple mathematical models and find that a parasite that initially evolves from the host through the loss of the ability to replicate autonomously must be substantially derived for a stable hostparasite coevolution regime to be established.

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Abundance of Tn3, Tn21, and Tn501 transposase (tnpA) sequences in bacterial community DNA from marine environments

Cited by 39 publications

References 44 publications

Marine algal toxins: Biochemistry, genetics, and molecular biology

Marine algal toxins: Biochemistry, genetics, and molecular biology

The prevalence and diversity of mobile genetic elements in bacterial communities of different environmental habitats: insights gained from different methodological approaches

Stability of host-parasite systems: you must differ to coevolve

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