Spiroplasma

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Spiroplasma
Spiro.jpg
Corn stunt Spiroplasma in phloem cells. Thick section (0.4 micrometers) observed in a TEM. Magnified 75,000X.
Scientific classification
Domain:
Phylum:
Class:
Order:
Family:
Spiroplasmataceae

Skrypal 1974 ex Skrypal 1983
Genus:
Spiroplasma

Saglio et al. 1973
Type species
Spiroplasma citri
Saglio et al. 1973
Species [1]

Spiroplasma is a genus of Mollicutes, a group of small bacteria without cell walls. Spiroplasma shares the simple metabolism, parasitic lifestyle, fried-egg colony morphology and small genome of other Mollicutes, but has a distinctive helical morphology, unlike Mycoplasma . It has a spiral shape and moves in a corkscrew motion. Many Spiroplasma are found either in the gut or haemolymph of insects where they can act to manipulate host reproduction, or defend the host as endosymbionts. Spiroplasma are also disease-causing agents in the phloem of plants. Spiroplasmas are fastidious organisms, which require a rich culture medium. Typically they grow well at 30 °C, but not at 37 °C. A few species, notably Spiroplasma mirum , grow well at 37 °C (human body temperature), and cause cataracts and neurological damage in suckling mice. The best studied species of spiroplasmas are Spiroplasma poulsonii , a reproductive manipulator and defensive insect symbiont, Spiroplasma citri , the causative agent of citrus stubborn disease, and Spiroplasma kunkelii , the causative agent of corn stunt disease.

Contents

Human pathogenicity

There is some disputed evidence for the role of spiroplasmas in the etiology of transmissible spongiform encephalopathies (TSEs), due primarily to the work of Frank Bastian, summarized below. Other researchers have failed to replicate this work, while the prion model for TSEs has gained very wide acceptance. [2] A 2006 study appears to refute the role of spiroplasmas in the best small animal scrapie model (hamsters). [3] Bastian et al. (2007) have responded to this challenge with the isolation of a spiroplasma species from scrapie-infected tissue, grown it in cell-free culture, and demonstrated its infectivity in ruminants. [4]

Insect symbioses

Many Spiroplasma strains are vertically transmitted endosymbionts of Drosophila species, with a variety of host-altering mechanisms similar to Wolbachia . These strains are from the Spiroplasma poulsonii clade, and can have important effects on host fitness. The S. poulsonii strain of Drosophila neotestacea protects its host against parasitic nematodes. This interaction is an example of defensive symbiosis, where the fitness of the symbiont is intricately tied to the fitness of the host. The D. neotestaceaS. poulsonii also defends its fly host from infestation by parasitic wasps. [5] [6] The mechanism through which S. poulsonii attacks nematodes and parasitic wasps relies on the presence of toxins called ribosome-inactivating proteins (RIPs), similar to Sarcin or Ricin. [7] These toxins depurinate a conserved adenine site in eukaryotic 28s ribosomal RNA called the Sarcin-Ricin loop by cleaving the N-glycosidic bond between the rRNA backbone and the adenine. [7] Spiroplasma associations highlight a growing movement to consider heritable symbionts as important drivers in patterns of evolution. [8] [9]

The S. poulsonii strain of Drosophila melanogaster can also attack parasitoid wasps, but is not regarded as a primarily defensive symbiont. This is because this D. melanogasterSpiroplasma (called MSRO) kills D. melanogaster eggs fertilized by Y-bearing sperm. This mode of reproductive manipulation benefits the symbiont as the female fly has a greater reproductive output than males. The genetic basis of this male-killing was discovered in 2018, solving a decades-old mystery of how the bacteria targeted male-specific cells. [10] In an interview with the Global Health Institute, Dr. Toshiyuki Harumoto said this discovery is the first example of a bacterial effector protein that affects host cellular machinery in a sex-specific manner, and the first endosymbiont factor identified to explain the cause of male-killing. Thus it should have a big impact on the fields of symbiosis, sex determination, and evolution. [11]

Beyond Drosophila, Spiroplasma of the ixodetis, apis, chrysopicola, citri, mirum, and poulsonii clades are found in many insects and arthropods, including ticks, spiders, bees, ants, beetles, and butterflies. [12] [13] [1] [14] Male-killing is also found in the Spiroplasma of the ladybug Harmonia axyridis and the plain tiger butterfly. In the plain tiger butterfly, the consequences have led to speciation. [15]

Plant diseases

Spiroplasma citri is the causative agent of Citrus stubborn disease, a plant disease affecting species in the genus Citrus . [16] It infects the phloem of the affected plant, causing fruit deformities. Spiroplasma kunkelii is also referred to as Corn Stunt Spiroplasma as it is the causative agent of Corn stunt disease, a disease of corn and other grasses that stunts plant growth. Spiroplasma kunkelii represents a major economic risk, as corn production in the United States is an industry worth over $50 billion. [17] Both Spiroplasma citri and Spiroplasma kunkelii are transmitted by leafhoppers. [18] [19]

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [20] and National Center for Biotechnology Information (NCBI) [21]

16S rRNA based LTP_08_2023 [22] [23] [24] 120 marker proteins based GTDB 08-RS214 [25] [26] [27]

Metamycoplasmataceae

Mycoplasmoidales

Mycoplasmoidaceae

Spiroplasma

Spiroplasma ixodetisTully et al. 1995

Spiroplasma platyhelixWilliamson et al. 1997

speciesgroup 3
Mycoplasmatales
Spiroplasma

S. eriocheirisWang et al. 2011

S. atrichopogonisKoerber et al. 2005

S. mira corrig. Tully et al. 1982

S. chrysopicolaWhitcomb et al. 1997

S. syrphidicolaWhitcomb et al. 1996

S. insolitacorrig. Hackett et al. 1993

S. penaeiNunan et al. 2005

S. leucomaeOduori, Lipa & Gasparich 2005

S. poulsonii Williamson et al. 1999

S. phoeniceacorrig. Saillard et al. 1987

S. kunkelii Whitcomb et al. 1986

S. citri Saglio et al. 1973

S. melliferacorrig. Clark et al. 1985

Spiroplasmataceae
Spiroplasma

Spiroplasma alleghenense

Spiroplasma sabaudiense

Spiroplasma lampyridicola

Spiroplasma leptinotarsae

Spiroplasma clarkii

Spiroplasma apis

Spiroplasma montanense

Spiroplasma taiwanense

Spiroplasma monobiae

Spiroplasma cantharicola

Spiroplasma diminutum

Spiroplasma floricola

Spiroplasma diabroticae

Mesoplasma melaleucae

Spiroplasma culicicola

Spiroplasma chinense

Spiroplasma velocicrescens

Spiroplasma litorale

Spiroplasma corruscae

Spiroplasma turonicum

Spiroplasma helicoides

Spiroplasma gladiatoris

Spiroplasma lineolae

Spiroplasma tabanidicola

speciesgroup 2

" Edwardiiplasma "

Entomoplasmataceae

Entomoplasma

Mesoplasma corruscae

Mesoplasma

Mycoplasmataceae

" Tullyiplasma "

Williamsoniiplasma

Mycoplasma

"Ca. Spiroplasma holothuricola" He et al. 2018

Mycoplasmoidaceae

"Hepatoplasmataceae"

Metamycoplasmataceae

VBWQ01
Spiroplasma

Spiroplasma ixodetis

Spiroplasma platyhelix

speciesgroup 3
Mycoplasmataceae
Spiroplasma

S. eriocheiris

S. mira

S. chrysopicola

S. syrphidicola

S. poulsonii

S. phoenicea

S. citri

S. mellifera

Spiroplasma

Spiroplasma alleghenense

Spiroplasma sabaudiense

Spiroplasma turonica

Spiroplasma corruscae

Spiroplasma litorale

Spiroplasma taiwanense

Spiroplasma cantharicola

Spiroplasma diminuta

Spiroplasma floricola

Spiroplasma monobiae

Spiroplasma apis

Spiroplasma clarkii

Spiroplasma culicicola

Spiroplasma chinense

Spiroplasma helicoides

Spiroplasma gladiatoris

Spiroplasma tabanidicola

speciesgroup 2

" Edwardiiplasma "

Williamsoniiplasma

" Tullyiplasma "

Entomoplasma

Mesoplasma

Mycoplasma

See also

Related Research Articles

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<span class="mw-page-title-main">Endosymbiont</span> Organism that lives within the body or cells of another organism

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<i>Rickettsia</i> Genus of bacteria

Rickettsia is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci, bacilli, or threads. The genus was named after Howard Taylor Ricketts in honor of his pioneering work on tick-borne spotted fever.

Transmissible spongiform encephalopathies (TSEs) also known as prion diseases, are a group of progressive, incurable, and fatal conditions that are associated with prions and affect the brain and nervous system of many animals, including humans, cattle, and sheep. According to the most widespread hypothesis, they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection. Mental and physical abilities deteriorate and many tiny holes appear in the cortex causing it to appear like a sponge when brain tissue obtained at autopsy is examined under a microscope. The disorders cause impairment of brain function, including memory changes, personality changes and problems with movement that worsen chronically.

"Candidatus Midichloria" is a candidatus genus of Gram-negative, non-endospore-forming bacteria, with a bacillus shape around 0.45 µm in diameter and 1.2 µm in length. First described in 2004 with the temporary name IricES1, "Candidatus Midichloria" species are symbionts of several species of hard ticks. They live in the cells of the ovary of the females of this tick species. These bacteria have been observed in the mitochondria of the host cells, a trait that has never been described in any other symbiont of animals.

The hologenome theory of evolution recasts the individual animal or plant as a community or a "holobiont" – the host plus all of its symbiotic microbes. Consequently, the collective genomes of the holobiont form a "hologenome". Holobionts and hologenomes are structural entities that replace misnomers in the context of host-microbiota symbioses such as superorganism, organ, and metagenome. Variation in the hologenome may encode phenotypic plasticity of the holobiont and can be subject to evolutionary changes caused by selection and drift, if portions of the hologenome are transmitted between generations with reasonable fidelity. One of the important outcomes of recasting the individual as a holobiont subject to evolutionary forces is that genetic variation in the hologenome can be brought about by changes in the host genome and also by changes in the microbiome, including new acquisitions of microbes, horizontal gene transfers, and changes in microbial abundance within hosts. Although there is a rich literature on binary host–microbe symbioses, the hologenome concept distinguishes itself by including the vast symbiotic complexity inherent in many multicellular hosts. For recent literature on holobionts and hologenomes published in an open access platform, see the following reference.

<i>Spiroplasma phage 1-R8A2B</i> Species of virus

Spiroplasma phage 1-R8A2B is a filamentous bacteriophage in the genus Vespertiliovirus of the family Plectroviridae, part of the group of single-stranded DNA viruses. The virus has many synonyms, such as SpV1-R8A2 B, Spiroplasma phage 1, and Spiroplasma virus 1, SpV1. SpV1-R8A2 B infects Spiroplasma citri. Its host itself is a prokaryotic pathogen for citrus plants, causing Citrus stubborn disease.

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Howardula aoronymphium is a species of nematode that infects specialist mushroom-feeding fruit flies such as Drosophila falleni and Drosophila neotestacea. Mated female nematodes pierce the fly larva cuticle and take up residence in the hemolymph where they mature alongside the fly. When the adult fly ecloses, the nematode motherworm has reached full size and sheds juvenile nematodes into the hemolymph which are eventually excreted by either the fly anus or ovipositor. Howardula nematodes can severely impact fly egg development, as infection can effectively sterilize some species.

<i>Drosophila neotestacea</i> Species of fly

Drosophila neotestacea is a member of the testacea species group of Drosophila. Testacea species are specialist fruit flies that breed on the fruiting bodies of mushrooms. These flies will choose to breed on psychoactive mushrooms such as the Fly Agaric Amanita muscaria. Drosophila neotestacea can be found in temperate regions of North America, ranging from the north eastern United States to western Canada.

<i>Drosophila testacea</i> species group Species group of the subgenus Drosophila

The Drosophila testacea species group belongs to the Immigrans-tripunctata radiation of the subgenus Drosophila, and contains 4 species: Drosophila putrida, Drosophila neotestacea, Drosophila testacea, and Drosophila orientacea. Testacea species are specialist mushroom-feeding flies, and can metabolize toxic compounds in Amanita mushrooms. The Testacea species group is studied for its specialist ecology, population genetics, and bacterial endosymbionts. The North American species Drosophila neotestacea is perhaps the best-studied of the group for its interactions with parasitic wasps and nematodes, bacterial endosymbionts, and trypanosomatid parasites. Of note, selfish X chromosomes have been discovered in three of the four Testacea group species.

Spiroplasma poulsonii are bacteria of the genus Spiroplasma that are commonly endosymbionts of flies. These bacteria live in the hemolymph of the flies, where they can act as reproductive manipulators or defensive symbionts.

<i>Drosophila quinaria</i> species group Species group of the subgenus Drosophila

The Drosophila quinaria species group is a speciose lineage of mushroom-feeding flies studied for their specialist ecology, their parasites, population genetics, and the evolution of immune systems. Quinaria species are part of the Drosophila subgenus.

Mushroom-feeding <i>Drosophila</i> Species group of the subgenus Drosophila

Mushroom-feeding Drosophila are a subset of Drosophila flies that have highly specific mushroom-breeding ecologies. Often these flies can tolerate toxic compounds from Amanita mushrooms.

<i>Drosophila innubila</i> Species of fly

Drosophila innubila is a species of vinegar fly restricted to high-elevation woodlands in the mountains of the southern USA and Mexico, which it likely colonized during the last glacial period. Drosophila innubila is a kind of mushroom-breeding Drosophila, and member of the Drosophila quinaria species group. Drosophila innubila is best known for its association with a strain of male-killing Wolbachia bacteria. These bacteria are parasitic, as they drain resources from the host and cause half the infected female's eggs to abort. However Wolbachia may offer benefits to the fly's fitness in certain circumstances. The D. innubila genome was sequenced in 2019.

John Jaenike is an ecologist and evolutionary biologist, and currently a professor at the University of Rochester New York. Jaenike was an early proponent of the Red Queen hypothesis, using the idea to explain the maintenance of sex. Jaenike is also known for his extensive work on mushroom-feeding Drosophila and the evolution of their inherited bacterial symbionts Wolbachia and Spiroplasma poulsonii.

<span class="mw-page-title-main">Morganellaceae</span> Family of bacteria

The Morganellaceae are a family of Gram-negative bacteria that include some important human pathogens formerly classified as Enterobacteriaceae. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Pseudomonadota. Genera in this family include the type genus Morganella, along with Arsenophonus, Cosenzaea, Moellerella, Photorhabdus, Proteus, Providencia and Xenorhabdus.

<i>Spiroplasma kunkelii</i> Species of bacteria

Spiroplasma kunkelii is a species of Mollicutes, which are small bacteria that all share a common cell wall-less feature. They are characterized by helical and spherical morphology, they actually have the ability to be spherical or helical depending on the circumstances. The cells movement is bound by a membrane. The cell size ranges from 0.15 to 0.20 micrometers.

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