Drosophila is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies ; tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly.
An endosymbiont or endobiont is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον endon "within", σύν syn "together" and βίωσις biosis "living".) Examples are nitrogen-fixing bacteria, which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects.
Drosophila melanogaster is a species of fly in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly", or "banana fly". Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, D. melanogaster continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and life history evolution. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect.
Wolbachia is a genus of intracellular bacteria that infects mainly arthropod species, including a high proportion of insects, and also some nematodes. It is one of the most common parasitic microbes, and is possibly the most common reproductive parasite in the biosphere. Its interactions with its hosts are often complex, and in some cases have evolved to be mutualistic rather than parasitic. Some host species cannot reproduce, or even survive, without Wolbachia colonisation. One study concluded that more than 16% of neotropical insect species carry bacteria of this genus, and as many as 25 to 70% of all insect species are estimated to be potential hosts.
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, 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.
A ribosome-inactivating protein (RIP) is a protein synthesis inhibitor that acts at the eukaryotic ribosome. This protein family describes a large family of such proteins that work by acting as rRNA N-glycosylase. They inactivate 60S ribosomal subunits by an N-glycosidic cleavage, which releases a specific adenine base from the sugar-phosphate backbone of 28S rRNA. RIPs exist in bacteria and plants.
Cytoplasmic incompatibility (CI) is a mating incompatibility reported in many arthropod species that is caused by intracellular parasites such as Wolbachia. These bacteria reside in the cytoplasm of the host cells and modify their hosts' sperm in a way that leads to embryo death unless this modification is 'rescued' by the same bacteria in the eggs. CI has been reported in many insect species, as well as in mites and woodlice. Aside from Wolbachia, CI can be induced by the bacteria Cardinium,Rickettsiella, Candidatus Mesenet longicola and Spiroplasma. CI is currently being exploited as a mechanism for Wolbachia-mediated disease control in mosquitoes.
Drosophila hydei (mosca casera) is a species of Diptera, or the order of flies, in the family Drosophilidae. It is a species in the hydei species subgroup, a group in the repleta species group. Bizarrely, it is also known for having approximately 23 mm long sperm, 10 times the length of the male's body. Drosophila hydei are commonly found on compost piles worldwide, and can be rudimentarily identified by eye owing to their large size and variegated pigment pattern on the thorax. The name derives from Dr R. R. Hyde, who first discovered that the species was distinct from Drosophila repleta. D. hydei are one of the more popular flies used as feeders in the pet trade. A few varieties are available, some flightless. They are very similar to Drosophila melanogaster, despite having separated 50 million years ago.
The microbiota are the sum of all symbiotic microorganisms living on or in an organism. The fruit fly Drosophila melanogaster is a model organism and known as one of the most investigated organisms worldwide. The microbiota in flies is less complex than that found in humans. It still has an influence on the fitness of the fly, and it affects different life-history characteristics such as lifespan, resistance against pathogens (immunity) and metabolic processes (digestion). Considering the comprehensive toolkit available for research in Drosophila, analysis of its microbiome could enhance our understanding of similar processes in other types of host-microbiota interactions, including those involving humans. Microbiota plays key roles in the intestinal immune and metabolic responses via their fermentation product, acetate.
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.
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.
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.
Diptericin is a 9 kDa antimicrobial peptide (AMP) of flies first isolated from the blowfly Phormia terranova. It is primarily active against Gram-negative bacteria, disrupting bacterial membrane integrity. The structure of this protein includes a proline-rich domain with similarities to the AMPs drosocin, pyrrhocoricin, and abaecin, and a glycine-rich domain with similarity to attacin. Diptericin is an iconic readout of immune system activity in flies, used ubiquitously in studies of Drosophila immunity. Diptericin is named after the insect order Diptera.
Drosocin is a 19-residue long antimicrobial peptide (AMP) of flies first isolated in the fruit fly Drosophila melanogaster, and later shown to be conserved throughout the genus Drosophila. Drosocin is regulated by the NF-κB Imd signalling pathway in the fly.
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.
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.
The Imd pathway is a broadly-conserved NF-κB immune signalling pathway of insects and some arthropods that regulates a potent antibacterial defence response. The pathway is named after the discovery of a mutation causing severe immune deficiency. The Imd pathway was first discovered in 1995 using Drosophila fruit flies by Bruno Lemaitre and colleagues, who also later discovered that the Drosophila Toll gene regulated defence against Gram-positive bacteria and fungi. Together the Toll and Imd pathways have formed a paradigm of insect immune signalling; as of September 2, 2019, these two landmark discovery papers have been cited collectively over 5000 times since publication on Google Scholar.
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.
Bruno Lemaitre is a French immunologist and a professor at the École Polytechnique Fédérale de Lausanne (EPFL). His research focuses on the mechanisms of innate immunity and endosymbiosis in Drosophila. Lemaitre has also authored several books on the topic of narcissism in science. and a book on the philosophy of Michael Polanyi.
