scholarly journals Low Densities of Epiphytic Bacteria from the Marine Alga Ulva australis Inhibit Settlement of Fouling Organisms

2007 ◽  
Vol 73 (24) ◽  
pp. 7844-7852 ◽  
Author(s):  
Dhana Rao ◽  
Jeremy S. Webb ◽  
Carola Holmström ◽  
Rebecca Case ◽  
Adrian Low ◽  
...  
Keyword(s):  
Marine Bacteria ◽  
Marine Fungi ◽  
Inhibitory Compounds ◽  
Ulva Australis ◽  
Petri Dishes ◽  
Cell Densities ◽  
Fouling Organisms ◽  
Invertebrate Larvae ◽  
Algal Spores

ABSTRACT Bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. Pseudoalteromonas tunicata and Phaeobacter sp. strain 2.10 (formerly Roseobacter gallaeciensis) are marine bacteria often found in association with the alga Ulva australis and produce a range of extracellular inhibitory compounds against common fouling organisms. P. tunicata and Phaeobacter sp. strain 2.10 biofilms with cell densities ranging from 102 to 108 cells cm−2 were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from U. australis), marine bacteria (Pseudoalteromonas gracilis, Alteromonas sp., and Cellulophaga fucicola), invertebrate larvae (Bugula neritina), and algal spores (Polysiphonia sp.) and gametes (U. australis). Remarkably low cell densities (102 to 103 cells cm−2) of P. tunicata were effective in preventing settlement of algal spores and marine fungi in petri dishes. P. tunicata also prevented settlement of invertebrate larvae at densities of 104 to 105 cells cm−2. Similarly, low cell densities (103 to 104cells cm−2) of Phaeobacter sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of P. tunicata on marine eukaryotic hosts is low (<1 × 103 cells cm−2) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of P. tunicata on U. australis in situ, our data suggest that P. tunicata and Phaeobacter sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that P. tunicata and Phaeobacter sp. strain 2.10 can play a role in defense against fouling on U. australis at cell densities that commonly occur in situ.

scholarly journals Microbial Colonization and Competition on the Marine Alga Ulva australis

2006 ◽  
Vol 72 (8) ◽  
pp. 5547-5555 ◽  
Author(s):  
Dhana Rao ◽  
Jeremy S. Webb ◽  
Staffan Kjelleberg
Keyword(s):  
Biofilm Formation ◽  
Microbial Colonization ◽  
Competitive Interactions ◽  
Plant Surface ◽  
Plant Host ◽  
Inhibitory Compounds ◽  
Ulva Australis ◽  
Mixed Microbial Community ◽  
Fouling Organisms ◽  
Major Surface

ABSTRACT Pseudalteromonas tunicata and Roseobacter gallaeciensis are biofilm-forming marine bacteria that are often found in association with the surface of the green alga Ulva australis. They are thought to benefit the plant host by producing inhibitory compounds that are active against common fouling organisms. We investigated factors that influence the ability of P. tunicata and R. gallaeciensis to attach to and colonize the plant surface and also the competitive interactions that occur between these organisms and other isolates from U. australis during biofilm formation on the plant surface. A surprisingly high number of P. tunicata cells, at least 108 cells ml−1, were required for colonization and establishment of a population of cells that persists on axenic surfaces of U. australis. Factors that enhanced colonization of P. tunicata included inoculation in the dark and pregrowth of inocula in medium containing cellobiose as the sole carbon source (cellulose is a major surface polymer of U. australis). It was also found that P. tunicata requires the presence of a mixed microbial community to colonize effectively. In contrast, R. gallaeciensis effectively colonized the plant surface under all conditions tested. Studies of competitive interactions on the plant surface revealed that P. tunicata was numerically dominant compared with all other bacterial isolates tested (except R. gallaeciensis), and this dominance was linked to production of the antibacterial protein AlpP. Generally, P. tunicata was able to coexist with competing strains, and each strain existed as microcolonies in spatially segregated regions of the plant. R. gallaeciensis was numerically dominant compared with all strains tested and was able to invade and disperse preestablished biofilms. This study highlighted the fact that microbial colonization of U. australis surfaces is a dynamic process and demonstrated the differences in colonization strategies exhibited by the epiphytic bacteria P. tunicata and R. gallaeciensis.

Chemical Defense and Antifouling Activity of Three Mediterranean Sponges of the Genus Ircinia

2002 ◽  
Vol 57 (1-2) ◽  
pp. 161-171 ◽  
Author(s):  
Maria Tsoukatou ◽  
Claire Hellio ◽  
Constantinos Vagias ◽  
Catherine Harvala ◽  
Vassilios Roussis
Keyword(s):  
Sea Urchin ◽  
Marine Bacteria ◽  
Marine Fungi ◽  
Generalist Predator ◽  
Antifeedant Activity ◽  
Antifouling Activity ◽  
Variable Level ◽  
Organic Extracts ◽  
Ircinia Oros ◽  
Fouling Organisms

The defense roles and the antifouling activity of the organic extracts and the major metabolites of the sponges Ircinia oros, I. variabilis and I. spinosula were investigated. The antifeedant activity was tested in experimental aquaria on the generalist predator fish Thalassoma pavo as well as in coastal ecosystems rich in fishes. Some of the major metabolites exhibited high levels of antifeedant activity. The antifouling activity was tested in laboratory assays, against representatives of the major groups of fouling organisms (marine bacteria, marine fungi, diatoms, macroalgae and mussels). All extracts showed promising levels of activity. As was expected, no single extract was active in all tests and some fractions that were effective against one organism showed little or no activity against the others. The high but variable level of antifouling activity in combination with the absence of toxicity (tested on the development of oyster and sea urchin larvae) shows the potential of these metabolites to become ingredients in environmentally friendly antifouling preparations.

scholarly journals Conjugal TOL Transfer from Pseudomonas putida to Pseudomonas aeruginosa: Effects of Restriction Proficiency, Toxicant Exposure, Cell Density Ratios, and Conjugation Detection Method on Observed Transfer Efficiencies

2005 ◽  
Vol 71 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Catalina Arango Pinedo ◽  
Barth F. Smets
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Putida ◽  
Strong Dependence ◽  
Plasmid Transfer ◽  
Mass Action ◽  
Tol Plasmid ◽  
Toxicant Exposure ◽  
Transfer Frequency ◽  
Cell Densities

ABSTRACT The effects of restriction proficiency and premating exposure to toxicants on conjugal transfer of the TOL plasmid between Pseudomonas spp. was investigated by examinations of filter matings. A Pseudomonas putida KT2442-derived strain carrying a gfp-tagged variant of the TOL plasmid was used as a donor, and both restriction-deficient (PAO1162N) and -proficient (PAO2002N) Pseudomonas aeruginosa strains were used as recipients. The in situ enumeration of conjugation events allowed us to obtain frequency estimates that were unbiased by transconjugant growth or plasmid retransfer. We observed a strong dependence of the plasmid transfer frequency on the initial donor-to-recipient ratio of surface matings, which invalidated the use of mass action-based plasmid transfer kinetic estimators. Careful control of the initial parental cell densities permitted evaluations of the true effects of restriction proficiency and toxicant exposure on TOL transfer. At standard donor-to-recipient ratios (10−3 for PAO1162N and 2 � 101 for PAO2002N) and total cell densities (105 cells/mm2 for PAO1162N and 106 cells/mm2 for PAO2002N), plasmid transfer frequencies without toxicant exposure were approximately 10−7 (events/mm2)−1 for PAO1162N and 10−11 (events/mm2)−1 for PAO2002N based on in situ observations of conjugation events. The enumeration of transconjugants via selective plating yielded transfer frequencies that were up to 1 order of magnitude lower. Premating exposure to sodium dodecyl sulfate (1 to 10 mM) significantly increased the transfer frequency for the restriction-proficient strain PAO2002N (P < 0.05) but not for the restriction-deficient strain PAO1162N. On the other hand, premating exposure to ethanol, toluene, or phenol had no positive effect on the plasmid transfer frequency. Clearly, restriction proficiency provides a strong barrier to interspecific transfer of the TOL plasmid, and this barrier was only marginally attenuated by recipient exposure to toxicants within the ranges examined.

scholarly journals Autofluorescence Is a Common Trait in Different Oceanic Fungi

2021 ◽  
Vol 7 (9) ◽  
pp. 709
Author(s):  
Eva Breyer ◽  
Markus Böhm ◽  
Magdalena Reitbauer ◽  
Chie Amano ◽  
Marilena Heitger ◽  
...  
Keyword(s):  
Marine Fungi ◽  
Physiological State ◽  
Excitation Wavelength ◽  
Growth Stages ◽  
Future Studies ◽  
Different Types ◽  
Widespread Phenomenon ◽  
Ubiquitous Presence ◽  
Different Growth Stages

Natural autofluorescence is a widespread phenomenon observed in different types of tissues and organisms. Depending on the origin of the autofluorescence, its intensity can provide insights on the physiological state of an organism. Fungal autofluorescence has been reported in terrestrial and human-derived fungal samples. Yet, despite the recently reported ubiquitous presence and importance of marine fungi in the ocean, the autofluorescence of pelagic fungi has never been examined. Here, we investigated the existence and intensity of autofluorescence in five different pelagic fungal isolates. Preliminary experiments of fungal autofluorescence at different growth stages and nutrient conditions were conducted, reflecting contrasting physiological states of the fungi. In addition, we analysed the effect of natural autofluorescence on co-staining with DAPI. We found that all the marine pelagic fungi that were studied exhibited autofluorescence. The intensity of fungal autofluorescence changed depending on the species and the excitation wavelength used. Furthermore, fungal autofluorescence varied depending on the growth stage and on the concentration of available nutrients. Collectively, our results indicate that marine fungi can be auto-fluorescent, although its intensity depends on the species and growth condition. Hence, oceanic fungal autofluorescence should be considered in future studies when fungal samples are stained with fluorescent probes (i.e., fluorescence in situ hybridization) since this could lead to misinterpretation of results.

Development of a microbe domestication pod (MD Pod) for in situ cultivation of micro‐encapsulated marine bacteria

2020 ◽  
Author(s):  
Tartela Alkayyali ◽  
Emily Pope ◽  
Sydney K. Wheatley ◽  
Christopher Cartmell ◽  
Bradley Haltli ◽  
...  
Keyword(s):  
Marine Bacteria

scholarly journals Use of Microautoradiography Combined with Fluorescence In Situ Hybridization To Determine Dimethylsulfoniopropionate Incorporation by Marine Bacterioplankton Taxa

2004 ◽  
Vol 70 (8) ◽  
pp. 4648-4657 ◽  
Author(s):  
Maria Vila ◽  
Rafel Simó ◽  
Ronald P. Kiene ◽  
Jarone Pinhassi ◽  
José M. González ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Gulf Of Mexico ◽  
Fluorescence In Situ Hybridization ◽  
Marine Bacteria ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
Mediterranean Coast ◽  
Marine Bacterioplankton ◽  
Significant Uptake

ABSTRACT The fraction of planktonic heterotrophic bacteria capable of incorporating dissolved dimethylsulfoniopropionate (DMSP) and leucine was determined at two coastal sites by microautoradioagraphy (AU). In Gulf of Mexico seawater microcosm experiments, the proportion of prokaryotes that incorporated sulfur from [35S]DMSP ranged between 27 and 51% of 4′,6-diamidino-2-phenylindole (DAPI)-positive cells, similar to or slightly lower than the proportion incorporating [3H]leucine. In the northwest Mediterranean coast, the proportion of cells incorporating sulfur from [35S]DMSP increased from 5 to 42% from January to March, coinciding with the development of a phytoplankton bloom. At the same time, the proportion of cells incorporating [3H]leucine increased from 21 to 40%. The combination of AU and fluorescence in situ hybridization (FISH) revealed that the Roseobacter clade (α-proteobacteria) accounted for 13 to 43% of the microorganisms incorporating [35S]DMSP at both sampling sites. Significant uptake of sulfur from DMSP was also found among members of the γ-proteobacteria and Cytophaga-Flavobacterium groups. Roseobacter and γ-proteobacteria exhibited the highest percentage of DAPI-positive cells incorporating 35S from DMSP (around 50%). Altogether, the application of AU with [35S]DMSP combined with FISH indicated that utilization of S from DMSP is a widespread feature among active marine bacteria, comparable to leucine utilization. These results point toward DMSP as an important substrate for a broad and diverse fraction of marine bacterioplankton.

In situ Demonstration and Characteristic Analysis of the Protease Components from Marine Bacteria Using Substrate Immersing Zymography

2014 ◽  
Vol 175 (1) ◽  
pp. 489-501 ◽  
Author(s):  
Dan Liu ◽  
XingHao Yang ◽  
JiaFeng Huang ◽  
RiBang Wu ◽  
CuiLing Wu ◽  
...  
Keyword(s):  
Marine Bacteria ◽  
Characteristic Analysis

XV.—Observations on the Development of the Proteus Group of Amœbæ

1957 ◽  
Vol 66 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Monica Taylor ◽  
Catherine Hayes ◽  
Mary Galbraith
Keyword(s):  
Water Immersion ◽  
Subsequent Development ◽  
Mature Adults ◽  
Petri Dishes

SynopsisDetails of what occurs in the interval between the hatching of amœbulæ from the spores of the Proteus group of amœbæ to the attainment of the adult condition (4–6 months) not hitherto known are described. The method consists in removing mature adults to petri dishes 4 in. in diameter, containing a dilute inorganic fluid which causes sporulation. The subsequent development of the hatching amœbulaæ can be traced in situ by means of a 4·4 mm. water immersion lens, and is seen to consist of feeding and growth alternating with periods of encystment. The time spent in cysts greatly exceeds that of activity.Some account of what takes place when cultures of the Proteus group, allowed to dry to a brownish dust, and then wetted, is given. Only in the case of A. proteus have the amœbulæ, which hatch out from the spores, been grown to maturity. It has been shown that the dried cultures used may comprise (1) spores, (2) cysts of varying size from which arise amœbulæ likewise varying in size.

scholarly journals Mobilization of shell calcium by the chick chorioallantoic membrane in vitro.

1994 ◽  
Vol 190 (1) ◽  
pp. 141-153
Author(s):  
M J Packard
Keyword(s):  
Domestic Fowl ◽  
Culture Medium ◽  
Chorioallantoic Membrane ◽  
The Other ◽  
Chick Chorioallantoic Membrane ◽  
Petri Dishes ◽  
Specific Degradation ◽  
Donor Eggs

Two explants of shell were removed from each of several fertile eggs of domestic fowl at different times during incubation. The chorioallantoic membrane (CAM) was removed from one of the explants (SHELL ONLY) and was left in situ on the other (SHELL+CAM). Explants were cultured for 24, 48 or 96 h at 37 degrees C and 5% CO2 in air in individual Petri dishes containing Dulbecco's modified Eagle's medium, bovine serum albumin, penicillin and streptomycin. Both SHELL+CAM and SHELL ONLY explants released calcium into the culture medium, but the former released considerably more calcium than the latter. More calcium was released by SHELL+CAM explants taken from older eggs than from younger ones, but the age of the donor eggs did not affect release of calcium by SHELL ONLY explants. In addition, release of calcium by SHELL+CAM explants exceeded that shown by SHELL ONLY explants for multiple 24 h intervals. However, the capacity for sustained release of calcium by SHELL+CAM explants declined with age and maturity of the CAM. Manipulations that lead to the death of the CAM abolish the capacity for SHELL+CAM explants to release more calcium than SHELL ONLY explants. Differential release of calcium by SHELL+CAM explants was not attributable to calcium present in the CAM at the onset of culture or to non-specific degradation of the shell by intracellular constituents released as a result of the death of the CAM. Taken in concert, these results indicate that the CAM mobilizes calcium from the eggshell during in vitro culture.

Sign in / Sign up

Export Citation Format

Share Document