Viruses as potential regulators of regional brown tide blooms caused by the alga,Aureococcus anophagefferens

Gastrich, Mary Downes; Leigh-Bell, Justine; Gobler, Christopher J.; Anderson, O. Roger; Wilhelm, Steven W.; Bryan, Martha

doi:10.1007/bf02803565

Cited by 70 publications

(73 citation statements)

References 26 publications

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“…Furthermore, TEM observations of viral-infected cells have consistently shown that the chloroplast of A. anophagefferens persists during the production of intracellular viral-like particles, even though other membranous organelles are degraded or absent ( Fig. 2A; Gastrich et al , 2004, indicating potential for cells to photosynthesize, even after viral infection. However, since control cultures growing at low light and with inactivated viruses did not grow substantially, we cannot fully discount the possibility that delayed lysis under low light may be due to reduced host growth rates, rather than low light.…”

Section: Discussionmentioning

confidence: 89%

“…To date, there has been a degree of uncertainty regarding the morphology of AaV as 2 distinct viral morpho-types have been reported. Intracellular viruses within field populations of Aureococcus anophagefferens (Sieburth et al 1988;Gastrich et al 1998Gastrich et al , 2004 and recently isolated viruses from NY and NJ waters ) have been shown to be icosahedral and 100 to 140 nm in diameter. In contrast, the first ever isolated AaV were shown to resemble 80 nm, tailed-phages (Milligan & Cosper 1994, Garry et al 1998) and have since been suspected of being a bacteriophage which had infected co-occurring bacteria in A. anophagefferens cultures.…”

Section: Discussionmentioning

confidence: 99%

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Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

Gobler¹,

Anderson²,

Gastrich³

et al. 2007

Aquat. Microb. Ecol.

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Although many bloom-forming phytoplankton are susceptible to viral lysis, the persistence of blooms of algal species that are susceptible to viral infection suggests that mechanisms prohibiting or minimizing viral infection and lysis are common. We describe the isolation of viruses capable of lysing the harmful brown tide pelagophyte Aureococcus anophagefferens and an investigation of factors which influence the susceptibility of A. anophagefferens cells to viral lysis. Nine strains of A. anophagefferens-specific viruses (AaV) were isolated from 2 New York estuaries which displayed 3-order of magnitude differences in ambient A. anophagefferens cell densities. The host range of AaV was species-specific and AaV was able to lyse 9 of 19 clonal A. anophagefferens cultures, suggesting that resistance to viral infection is common among these algal clones. Viral lysis of A. anophagefferens cultures was delayed at reduced light intensities, indicating that the low light conditions which prevail during blooms may reduce virally induced mortality of this alga. Some A. anophagefferens clones which were resistant to viral infection at 22°C were lysed by AaV at lower temperatures, suggesting that the induction of viral resistance at higher temperatures could allow the proliferation of blooms during summer months. The addition of laboratory propagated viruses to bottle-incubated bloom waters (>10 5 cells ml -1) from New York and Maryland estuaries resulted in a significant reduction in (p < 0.05), but not complete loss of, A. anophagefferens densities, suggesting that a resistant sub-population survived during experiments. In summary, the results demonstrate that clonal resistance, combined with the lower light levels and higher temperatures which are found during brown tides, may allow A. anophagefferens to form blooms during summer months.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

Gobler¹,

Anderson²,

Gastrich³

et al. 2007

Aquat. Microb. Ecol.

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“…Consequently, phytoplankton drive the development and structuring of other microbial entities and their interactions. Their link with viruses through viral infection has been clearly identified, particularly during bloom periods (Bratbak et al 1993, Brussaard et al 1995, Agusti et al 1998, with from 10 to 50% of algal cells visibly infected at the end of a specific bloom (Gastrich et al 2004). The release of phytoplankton cell content by viral lysis would provide enough DOM to meet the carbon demand of bacteria in the case of a phytoplankton decline (59 to 70%; Brussaard et al 2005).…”

Section: Abstract: Virus · Bacteria · Phytoplankton · Diversity · Ammentioning

confidence: 99%

In situ structuring of virioplankton through bacterial exoenzymatic activity: interaction with phytoplankton

Ory¹,

Palesse²,

Delmas³

et al. 2011

Aquat. Microb. Ecol.

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“…In these situations, one could expect close agreement between abundances estimated by the ELISA and IFCM methods. As a bloom progresses, however, consumption by microbial predators and/or lysis by viruses may have significant impacts on the number of viable A. anophagefferens organisms in the water (8,9,17,21,23,45). These trophic interactions could significantly reduce the number of intact cells that would be observed using IFCM, but cell fragments could retain sufficient antigenic character that the ELISA method might overestimate the abundance of intact cells.…”

Section: Discussionmentioning

confidence: 99%

Immunofluorescence Flow Cytometry Technique for Enumeration of the Brown-Tide Alga, Aureococcus anophagefferens

Stauffer

Schaffner

Wazniak

et al. 2008

Appl Environ Microbiol

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A new immunologically based flow cytometry (IFCM) technique was developed to enumerate Aureococcus anophagefferens, a small pelagophyte alga that is the cause of "brown tides" in bays and estuaries of the mid-Atlantic states along the U.S. coast. The method utilizes a monoclonal antibody conjugated to fluorescein isothiocyanate (FITC-MAb) to label the surface of A. anophagefferens cells which are then detected and enumerated by using a flow cytometer. Optimal conditions for FITC-MAb staining, including solution composition, incubation times, and FITC-MAb concentrations, were determined. The FITC-MAb method was tested for cross-reactivity with nontarget, similarly sized, photoautotrophic protists, and the method was compared to an enzyme-linked immunosorbent assay (ELISA) using the same MAb. Comparisons of the IFCM technique to traditional microscopy enumeration of cultures and spiked environmental samples showed consistent agreement over several orders of magnitude (r 2 > 0.99). Comparisons of the IFCM and ELISA techniques for enumerating cells from a predation experiment showed a substantial overestimation (up to 10 times higher) of the ELISA in the presence of consumers of A. anophagefferens, presumably due to egested cell fragments that retained antigenicity, using the ELISA method, but were not characterized as whole algal cells by the IFCM method. Application of the IFCM method to environmental "brown-tide" samples taken from the coastal bays of Maryland demonstrated its efficacy in resolving A. anophagefferens abundance levels throughout the course of a bloom and over a large range of abundance values. IFCM counts of the brown-tide alga from natural samples were consistently lower than those obtained using the ELISA method and were equivalent to those of the polyclonal immunofluorescence microscopy technique, since both methods discriminate intact cells. Overall, the IFCM approach was an accurate and relatively simple technique for the rapid enumeration of A. anophagefferens in natural samples over a wide range of abundance values (10 3 to 10 6 cells ml ؊1 ).

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Viruses as potential regulators of regional brown tide blooms caused by the alga,Aureococcus anophagefferens

Cited by 70 publications

References 26 publications

Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

In situ structuring of virioplankton through bacterial exoenzymatic activity: interaction with phytoplankton

Immunofluorescence Flow Cytometry Technique for Enumeration of the Brown-Tide Alga, Aureococcus anophagefferens

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Viruses as potential regulators of regional brown tide blooms caused by the alga,Aureococcus anophagefferens

Cited by 70 publications

References 26 publications

Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

Ecological aspects of viral infection and lysis in the harmful brown tide alga Aureococcus anophagefferens

In situ structuring of virioplankton through ­bacterial exoenzymatic activity: interaction with phytoplankton

Immunofluorescence Flow Cytometry Technique for Enumeration of the Brown-Tide Alga, Aureococcus anophagefferens

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In situ structuring of virioplankton through bacterial exoenzymatic activity: interaction with phytoplankton