Moraxella osloensis
Encyclopedia
Moraxella osloensis is a species
of Gram-negative
oxidase positive, aerobic
bacteria
within the family Moraxellaceae
in the gamma subdivision of the purple bacteria.
The bacterium Moraxella osloensis is a mutualistic symbiont of the slug-parasitic nematode Phasmarhabditis hermaphrodita
. In nature, Phasmarhabditis hermaphrodita vectors Moraxella osloensis into the shell cavity of the slug
host in which the bacteria multiply and kill the slug.
, Phasmarhabditis hermaphrodita
(Rhabditida
: Rhabditidae
), which is an endoparasite of slugs, including the slug Deroceras reticulatum
(grey garden slug) which is one of the most serious agricultural and garden slug pests.
In nature, bacteria colonize the gut
of nematode infective juveniles which represent a specialized stage of development adapted for survival in the unfavorable environment. The infective juveniles seek out and enter the slug's shell cavity through the posterior mantle
region. Once inside the shell cavity, the bacteria are released, and the infective juveniles resume growth, feeding on the multiplying bacteria. The infected slugs die in 4–10 days, and the nematodes colonize the entire cadaver and produce next generation infective juveniles which leave the cadaver to seek a new host. It is the bacteria which are responsible for killing the slugs; nematodes without bacteria do not cause death.
, that is an endotoxin
, from Moraxella osloensis is a molluscicide
for Deroceras reticulatum
when applied by injection
.
The lethality of these nematodes to slugs has been shown to correlate with the number of Moraxella osloensis cells carried by infective juveniles. Tan and Grewal (2001) demonstrated that the 72 h old Moraxella osloensis cultures inoculated into the shell cavity were highly pathogenic to the slug. They further reported that Moraxella osloensis produced an endotoxin which was identified to be a rough type lipopolysaccharide with a molecular weight of 5300 KD, and the purified Moraxella osloensislipopolysaccharide was toxic to the slug with an estimated 50% lethal dose of 48 μg when injected into the shell cavity.
s are usually effective against such infections.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
oxidase positive, aerobic
Aerobic organism
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.Faculitative anaerobes grow and survive in an oxygenated environment and so do aerotolerant anaerobes.-Glucose:...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
within the family Moraxellaceae
Moraxellaceae
The Moraxellaceae are a family of Gammaproteobacteria, including a few pathogenic species. Other are harmless parasites of mammals and humans or occur in water or soil...
in the gamma subdivision of the purple bacteria.
The bacterium Moraxella osloensis is a mutualistic symbiont of the slug-parasitic nematode Phasmarhabditis hermaphrodita
Phasmarhabditis hermaphrodita
Phasmarhabditis hermaphrodita is a microscopic nematode in the family Rhabditidae. It is a lethal parasite of the slug, Deroceras reticulatum and a large number of other slug species from the families Milacidae, Limacidae and Arionidae...
. In nature, Phasmarhabditis hermaphrodita vectors Moraxella osloensis into the shell cavity of the slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
host in which the bacteria multiply and kill the slug.
Life cycle
This bacterium has been identified as one of the natural symbionts of a bacteria-feeding nematodeNematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
, Phasmarhabditis hermaphrodita
Phasmarhabditis hermaphrodita
Phasmarhabditis hermaphrodita is a microscopic nematode in the family Rhabditidae. It is a lethal parasite of the slug, Deroceras reticulatum and a large number of other slug species from the families Milacidae, Limacidae and Arionidae...
(Rhabditida
Rhabditida
Rhabditida is an order of free-living, zooparasitic and phytoparasitic microbivorous nematodes .Order include 8 superfamilies.Diagnosis:...
: Rhabditidae
Rhabditidae
Rhabditidae is a family of nematodes.-Genera:-Caenorhabditis:*Caenorhabditis brenneri Sudhaus & Kiontke, 2007*Caenorhabditis briggsae *Caenorhabditis dolichura *Caenorhabditis elegans Maupas, 1900*Caenorhabditis rara...
), which is an endoparasite of slugs, including the slug Deroceras reticulatum
Deroceras reticulatum
Deroceras reticulatum, common names "grey field slug" and "grey garden slug", is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Agriolimacidae...
(grey garden slug) which is one of the most serious agricultural and garden slug pests.
In nature, bacteria colonize the gut
Gut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
of nematode infective juveniles which represent a specialized stage of development adapted for survival in the unfavorable environment. The infective juveniles seek out and enter the slug's shell cavity through the posterior mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
region. Once inside the shell cavity, the bacteria are released, and the infective juveniles resume growth, feeding on the multiplying bacteria. The infected slugs die in 4–10 days, and the nematodes colonize the entire cadaver and produce next generation infective juveniles which leave the cadaver to seek a new host. It is the bacteria which are responsible for killing the slugs; nematodes without bacteria do not cause death.
Biochemistry
The lipopolysaccharideLipopolysaccharide
Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...
, that is an endotoxin
Endotoxin
Endotoxins are toxins associated with some Gram-negative bacteria. An "endotoxin" is a toxin that is a structural molecule of the bacteria that is recognized by the immune system.-Gram negative:...
, from Moraxella osloensis is a molluscicide
Molluscicide
Molluscicides, also known as snail baits and snail pellets, are pesticides against molluscs, which are usually used in agriculture or gardening to control gastropod pests like slugs and snails that can damage crops by feeding on them....
for Deroceras reticulatum
Deroceras reticulatum
Deroceras reticulatum, common names "grey field slug" and "grey garden slug", is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Agriolimacidae...
when applied by injection
Injection (medicine)
An injection is an infusion method of putting fluid into the body, usually with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body...
.
The lethality of these nematodes to slugs has been shown to correlate with the number of Moraxella osloensis cells carried by infective juveniles. Tan and Grewal (2001) demonstrated that the 72 h old Moraxella osloensis cultures inoculated into the shell cavity were highly pathogenic to the slug. They further reported that Moraxella osloensis produced an endotoxin which was identified to be a rough type lipopolysaccharide with a molecular weight of 5300 KD, and the purified Moraxella osloensislipopolysaccharide was toxic to the slug with an estimated 50% lethal dose of 48 μg when injected into the shell cavity.
Infections of humans
Although M. osloensis rarely infects humans, it can sometimes be found in a variety of tissues, where it sometimes causes disease. AntibioticAntibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s are usually effective against such infections.
Classification
The species M. osloensis was proposed in 1967; the bacteria which are now considered to be M. osloensis would previously have been considered to be Moraxella nonliquefaciens or Mima polymorpha (var.) oxidans.External links
- http://www.ncbi.nlm.nih.gov/pubmed?term=Moraxella%20osloensis&itool=QuerySuggestion