Table 1.
Overview of studied interactions between Ulvales and associated bacteria related to bacteria induced morphogenesis (in chronological order).
| Algal Species | Source for the preparation of axenic cultures | Methodology to prepare axenic cultures | Experimental details of axenicity tests | Representative isolated morphogenesis-inducing bacteria (= MG active) | References |
|---|---|---|---|---|---|
| Ulva lactuca | Small pieces of the thallus (1–5 mm2) were placed on antibiotic treated and melted agar. | Mixture of four antibiotics: penicillin G, chloramphenicol, neomycin, polymyxin B sulfate | Smaller strips of the axenic culture were inoculated in enriched seawater ASWIII or ASW8 for testing. | Bacteria were not isolated. | Provasoli, 1958b |
| Enteromorpha linza | Small pieces of the algae | Mixture of two antibiotics: penicillic acid, streptomycin sulfate | Test medium: ASP 6F + Glucose (Fries, 1963) | Bacteria were not isolated. | Berglund, 1969a,b |
| Enteromorpha linza Enteromorpha compressa | Same material was used by Berglund (1969a,b) | Mixture of two antibiotics: penicillin, streptomycin | Not reported | Bacteria were not isolated. | Fries, 1975 |
| Ulva lactuca | “Swarmers” from axenic thallus | Dragged through agar, 15 antibiotics, 8 sulfa drugs, fungicide, Jodopax | Sterility test based on STP and ST3 media according to Tatewaki and Provasoli (1964) and by electron microscopy | Bacteria were not isolated. | Bonneau, 1977, 1978 |
| Ulva lactuca | Axenically maintained strain Ulva-58 prepared by Provasoli (1958b) was used. | Mixture of four Antibiotics: penicillin G, chloramphenicol, neomycin, polymyxin B sulfate | Smaller strips of the axenic culture were inoculated in enriched seawater ASWIII or ASW8 for testing (Provasoli, 1958b). | Bacteria with MG were isolated, but not further characterized (Provasoli and Pintner, 1980). | Provasoli and Pintner, 1977, 1980 |
| Monostroma oxyspermum | Motile germ cells: gametes or zoospores | Axenic cultures were obtained by repeatedly washing of motile stages with capillary pipettes or by washing thalli through the “dip and drag” treatment inside agar plates. | According the sterility test based on STP and ST3 media (Tatewaki and Provasoli, 1964) | Bacteria were not isolated (study with bialgal cultures). | Tatewaki, 1983 |
| Ulva pertusa | Axenic female strain of U. pertusa (strain UP-203) was maintained aseptically. | Not reported | Platting on various agar media e.g., ST3, 2216 (Difco, USA), ESS1B1, ESS1B2 (Nakanishi and Saga, 1993) | – 1555 strains were isolated from 18 macroalgae, – 676 were MG active selected genera: Cytophaga, Flavobacterium, Vibrio, Pseudomonas, Halomonas, Escherichia. | Nakanishi et al., 1996, 1999 |
| Monostroma oxyspermum | Unicellular strain MK-001 of M. oxyspermum in axenic culture | Not reported for M. oxyspermum | Not reported | – 1000 strains were isolated from macroalgae and corals, – 50 MG active strains belonged to the Cytophaga-Flavobacterium-Bacteroides-complex | Matsuo et al., 2003, 2005 |
| Ulva pertusa | Motile germ cells were collected from Ulva strains. | For Ulva: germ cells were treated with antibiotics: penicillin G, streptomycin, erythromycin, kanamycin. | Thallusin producing strain: Cytophaga sp. (YM2-23) was isolated from M. oxyspermum. | ||
| Ulva conglobata | |||||
| Enteromorpha intestinalis | |||||
| Ulva linza | Released zoospores were collected from axenic thallus strips. | Antibiotics: penicillin G, streptomycin, norfloxacin, kanamycin | Zoospores were spread on artificial algal agar medium | – 38 strains were isolated from three Ulva species, – 20 strains were MG active, selected strains: Cellulophaga sp. (UL16), Cytophaga sp. (UC19), Psychrobacter sp. (ULA5), Pseudoalteromonas sp. (UL34), Shewanella sp. (UL19). | Marshall et al., 2006 |
| Axenic calli were picked off after 35 days and cultivated in UCM (Stratmann et al., 1996). | |||||
| Ulva fasciata | Zoospores were collected from axenic thallus. | Chemical treatment with detergent and povidone-iodine followed by antibiotic treatment (Kumar et al., 1999; Reddy et al., 2006) | Axenicity of the algal culture was tested by incubating randomly selected algal tissue on nutrient and Zobell's agar medium (Zobell, 1941). | – 53 strains were isolated from different Ulva/Gracilaria species | Singh et al., 2011 |
| – 5 strains were MG active | |||||
| Bacillus flexus (UL) | |||||
| Bacillus sp. (GS) | |||||
| Bacillus sp. (UL24) | |||||
| Bacillus licheniformis (GC) | |||||
| Marinomonas sp. (UF). | |||||
| Ulva mutabilis | Positively phototactic gametes were collected. | Axenic cultures were obtained by repeatedly washing of gametes via their strong positively phototactic response in capillary pipettes | Platting on marine broth agar plates (2216, Difco, USA) and by direct PCR of 16S rDNA in algal growth media | – 12 strains were isolated from U. mutabilis, | Spoerner et al., 2012 |
| – 4 strains were MG active | |||||
| Cytophaga sp. (MS6) | |||||
| Roseobacter sp.(MS2) | |||||
| Sulfitobacter sp. (MS3) | |||||
| Halomonas sp. (MS1). | |||||
| Ulva linza | Positively phototactic gametes were collected. | Axenic cultures were obtained by repeatedly washing of gametes via their strong positively phototactic response in capillary pipettes. | Platting on marine broth agar plates (2216, Difco, USA) | Cross-test with Cytophaga sp. (MS6) and Roseobacter sp. (MS2) originally isolated from U. mutabilis (Spoerner et al., 2012) | Vesty et al., 2015 |
Methodologies and representative isolated strains are listed, which were particularly tested or mentioned. The closest matching strain in Genbank/EMBL was usually given in the respective study; the accession number of the 16S rDNA analyses can be found in the cited publication. Bacteria were isolated from various macroalgae species in most studies.