Characteristics and growth of Photorhabdus luminescens, the bacteria associated with entomopathogenic nematodes

NAHODILOVÁ, Iveta. Characteristics and growth of Photorhabdus luminescens, the bacteria associated with entomopathogenic nematodes. In Kostelecké inspirování. 2019. ISBN 978-80-213-2981-2.

Základní údaje

• Originální název: Characteristics and growth of Photorhabdus luminescens, the bacteria associated with entomopathogenic nematodes
• Autoři: NAHODILOVÁ, Iveta (203 Česká republika, garant, domácí).
• Vydání: Kostelecké inspirování, 2019.

Další údaje

• Originální jazyk: angličtina
• Typ výsledku: Konferenční abstrakt
• Obor: 10606 Microbiology
• Stát vydavatele: Česká republika
• Utajení: není předmětem státního či obchodního tajemství
• Kód RIV: RIV/00216224:14310/19:00111453
• Organizační jednotka: Přírodovědecká fakulta
• ISBN: 978-80-213-2981-2
• Klíčová slova česky: Photorhabdus luminescens; patogenní bakterie; Heterorhabditis bacteriophora; entomopatogenní hlístice; patogen hmyzu; bioluminiscence; fázová variace
• Klíčová slova anglicky: Photorhabdus luminescens; pathogenic bacteria; Heterorhabditis bacteriophora; entomopathogenic nematodes; insect pathogen; bioluminescence; phase variant
• Příznaky: Mezinárodní význam

Anotace

Photorhabdus luminescens are gram-negative bacteria of the family Morganellaceae, which live symbiotically in the gut of entomopathogenic nematode Heterorhabditis bacteriophora. These bacteria are nonpathogenic to nematodes, but they are lethal pathogen of insect. When the nematodes penetrate into the insect body through the digestive system or by disrupting the cuticule, they begin to consciously release bacteria into the haemocoel and together cause its death by producing toxins and other substances inhibiting host immunity. Bacteria also produce enzymes, which break down the insect host body; subsequently both of them can receive nutrients for their proliferation in the insect cadaver. In order to complete this cycle, the bacteria then enter the nematode juveniles as they develop. Nematodes are not only bound to the host, but can also live in a humid soil. P. luminescens forms two phases which are genetically identical, but morphologically different. Cells of Phase I are known as the pathogenic ones which are associated with infective juveniles. They absorb dye from agar media, produce pigments, antibiotic substances, toxins, lipase, protease or lectins and they are also bioluminescent. Phase II cells lose most of these abilities. They could not produce many substances and do not show any light emission. However, they also product pigments but not as strongly as Phase I cells. We can distinguish these phases on special agar medium - MacConkey and NBTA agar. Phase I absorb crystal violet from MacConkey agar and cells are deeply red here. Cells of Phase II are usually very pale or pink here because they could not absorb any dye. Similarly, on NBTA agar Phase I cells could absorb bromothymol blue, thus it appears blue or green and Phase II cells are characterized by red color. To verify the phase we measured the plates in a luminometer. Also growth of these bacteria was measured in a luminometer and the level of emitted light increased with the optical density.

Anotace česky

Photorhabdus luminescens are gram-negative bacteria of the family Morganellaceae, which live symbiotically in the gut of entomopathogenic nematode Heterorhabditis bacteriophora. These bacteria are nonpathogenic to nematodes, but they are lethal pathogen of insect. When the nematodes penetrate into the insect body through the digestive system or by disrupting the cuticule, they begin to consciously release bacteria into the haemocoel and together cause its death by producing toxins and other substances inhibiting host immunity. Bacteria also produce enzymes, which break down the insect host body; subsequently both of them can receive nutrients for their proliferation in the insect cadaver. In order to complete this cycle, the bacteria then enter the nematode juveniles as they develop. Nematodes are not only bound to the host, but can also live in a humid soil. P. luminescens forms two phases which are genetically identical, but morphologically different. Cells of Phase I are known as the pathogenic ones which are associated with infective juveniles. They absorb dye from agar media, produce pigments, antibiotic substances, toxins, lipase, protease or lectins and they are also bioluminescent. Phase II cells lose most of these abilities. They could not produce many substances and do not show any light emission. However, they also product pigments but not as strongly as Phase I cells. We can distinguish these phases on special agar medium - MacConkey and NBTA agar. Phase I absorb crystal violet from MacConkey agar and cells are deeply red here. Cells of Phase II are usually very pale or pink here because they could not absorb any dye. Similarly, on NBTA agar Phase I cells could absorb bromothymol blue, thus it appears blue or green and Phase II cells are characterized by red color. To verify the phase we measured the plates in a luminometer. Also growth of these bacteria was measured in a luminometer and the level of emitted light increased with the optical density.