l
Assimilates salicin.
l
Grow at 37
C.
Xenorhabdus poinarii
l
Brown-shaded, intensity of pigmentation varies significantly
between strains.
l
They do not adsorb bromothymol blue.
l
Neutral red absorbed by Phase I colonies to form red colonies.
l
Some strains generate antibiotic factors.
l
Grow at 37
C.
Xenorhabdus nematophilus
l
Non-pigmented. Phase I adsorbs neutral red, developing brown
colonies on MacConkey agar, and bromothymol blue, yields
lecithinase.
l
Catalase negative.
l
Generation of indolpyruvic acid from tryptophan is variable
and weak.
l
Tween 85 and/or tributyrin are hydrolyzed.
l
Aesculin not hydrolyzed.
l
Does not grow at 37
C.
Xenorhabdus luminescens
l
Colored, forming yellow, orange, red, or pink colonies.
l
Phase I colonies adsorb neutral red, forms red colonies, and
bromothymol blue. They are mucoid.
l
Phase I yields lecithinase. Bioluminescent, intensity of bioluminescence varies, and in some strains, must be distinguished in a
scintillation counter.
l
Catalase positive.
l
Some strains yield indole.
l
Indolpyruvic acid is formed from tryptophan agar.
l
Robustly lipolytic, hydrolyzing Tweens 20-85, and tributyrin.
l
Aesculin hydrolyzed; phosphatase and urease generated.
2.1.2 Characters
of the Genus Photorhabdus
l
Gram-negative, asporogenous rods.
l
Cell size is exceedingly variable within and between cultures,
ranging from 0.5–2.0 to 2.0–10 μm.
l
Spheroplasts look like in the last third of exponential growth.
l
Birefringent inclusions happen within cells.
l
Motile, peritrichously flagellated. Anaerobic and facultative,
comprises respiratory and fermentative respiration.
118
Laboratory Techniques for Symbiotic Bacteria
Assimilates salicin.
l
Grow at 37
C.
Xenorhabdus poinarii
l
Brown-shaded, intensity of pigmentation varies significantly
between strains.
l
They do not adsorb bromothymol blue.
l
Neutral red absorbed by Phase I colonies to form red colonies.
l
Some strains generate antibiotic factors.
l
Grow at 37
C.
Xenorhabdus nematophilus
l
Non-pigmented. Phase I adsorbs neutral red, developing brown
colonies on MacConkey agar, and bromothymol blue, yields
lecithinase.
l
Catalase negative.
l
Generation of indolpyruvic acid from tryptophan is variable
and weak.
l
Tween 85 and/or tributyrin are hydrolyzed.
l
Aesculin not hydrolyzed.
l
Does not grow at 37
C.
Xenorhabdus luminescens
l
Colored, forming yellow, orange, red, or pink colonies.
l
Phase I colonies adsorb neutral red, forms red colonies, and
bromothymol blue. They are mucoid.
l
Phase I yields lecithinase. Bioluminescent, intensity of bioluminescence varies, and in some strains, must be distinguished in a
scintillation counter.
l
Catalase positive.
l
Some strains yield indole.
l
Indolpyruvic acid is formed from tryptophan agar.
l
Robustly lipolytic, hydrolyzing Tweens 20-85, and tributyrin.
l
Aesculin hydrolyzed; phosphatase and urease generated.
2.1.2 Characters
of the Genus Photorhabdus
l
Gram-negative, asporogenous rods.
l
Cell size is exceedingly variable within and between cultures,
ranging from 0.5–2.0 to 2.0–10 μm.
l
Spheroplasts look like in the last third of exponential growth.
l
Birefringent inclusions happen within cells.
l
Motile, peritrichously flagellated. Anaerobic and facultative,
comprises respiratory and fermentative respiration.
118
Laboratory Techniques for Symbiotic Bacteria