Thorselliaceae is a family of bacteria belonging to the class

Gammaproteobacteria ''Gammaproteobacteria'' is a class of bacteria in the phylum ''Pseudomonadota'' (synonym ''Proteobacteria''). It contains about 250 genera, which makes it the most genus-rich taxon of the Prokaryotes. Several medically, ecologically, and scienti ...

and it was first described in February 2015. It is not assigned to an order. The family consists of four species in two genera. The bacteria are

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

and rod shaped, approximately 1 μm wide and 2 μm long. They are

facultative anaerobes A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

and motile. Thorselliaceae bacteria have been found around the world associated with

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

mosquitoes, mainly with vectors of

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

. The first described species was ''Thorsellia anophelis''. It was isolated from the midgut of the malaria mosquito ''

Anopheles arabiensis ''Anopheles arabiensis'' is a zoophilic species of mosquito and a vector of disease endemic to Africa. Genome Polytene chromosomes have a high degree of gene polymorphism due to paracentric inversions. This is also unusually high for the g ...

'' from Kenya. This new bacterium was given its name after the Swedish researcher

Walborg Thorsell Walborg Susanna Thorsell (12 February 1919 – January 2016) was a Swedish scientist who performed research mainly on mosquitoes and mosquito repellents. Education Thorsell defended her thesis for her doctorate in veterinary medicine at the ...

who worked with mosquitoes and insecticides against mosquitoes for many years. ''Thorsellia'' bacteria have now been found in mosquito species that are the major vectors of malaria in Africa, Asia and South America. The bacteria have also been found in the waters where the malaria mosquitoes breed. Some properties of ''Thorsellia'' suggest that they are adapted to the mosquito guts, they can accept an alkaline pH, which is found in mosquito larvae and they grow faster in blood culture. However, ''T. anophelis'' has also been found in the reproductive tissues of male and female ''

Anopheles gambiae The ''Anopheles gambiae'' complex consists of at least seven morphologically indistinguishable species of mosquitoes in the genus ''Anopheles''. The complex was recognised in the 1960s and includes the most important vectors of malaria in sub- ...

'' and ''An''. ''coluzzii'' mosquitoes. Currently, little is known about Thorselliaceae in nature apart from that it has been shown in several studies that ''Thorsellia anophelis'' dominate the malaria mosquito

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

and their breeding waters. ''Thorsellia'' has besides in ''

Anopheles ''Anopheles'' () is a genus of mosquito first described by the German entomologist Johann Wilhelm Meigen, J. W. Meigen in 1818, and are known as nail mosquitoes and marsh mosquitoes. Many such mosquitoes are Disease vector, vectors of the paras ...

'' also been found to dominate the gut flora in the mosquito species ''

Culex tarsalis ''Culex tarsalis'', also known as Western Encephalitis Mosquito, is a mosquito species that appears across North America. The species has black and white banding on the legs. The species is a major vector of Saint Louis encephalitis and Wester ...

'', which is a vector of among other things,

West Nile virus West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family ''Flaviviridae'', from the genus ''Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The virus ...

and

encephalitis Encephalitis is inflammation of the Human brain, brain. The severity can be variable with symptoms including reduction or alteration in consciousness, aphasia, headache, fever, confusion, a stiff neck, and vomiting. Complications may include se ...

. It as also been shown that ''T. anophelis'' is much more abundant in ''Cx''. ''nigripalpus'' than in ''Cx''. ''coronator''. ''Coetzeea'' (named after the South African mosquito researcher

Maureen Coetzee Maureen Coetzee is a medical entomologist, specialising in African malaria vector mosquitoes for over 40 years. She is currently a Distinguished Professor in the Wits Research Institute for Malaria, School of Pathology at the University of the W ...

) has so far only been found in Brazilian ''

Anopheles darlingi ''Anopheles darlingi'', the American malaria mosquito, is a species of mosquito in the family Culicidae. ''A. darlingi'' is one of the major species of mosquito known to be responsible for malaria in the Amazonian regions. It has a wide range of ...

''.

Application

A possible application of Thorselliaceae is in

paratransgenesis Paratransgenesis is a technique that attempts to eliminate a pathogen from Vector (epidemiology), vector populations through transgenesis of a symbiont of the vector. The goal of this technique is to control vector-borne diseases. The first step is ...

to prevent the transmission of malaria. This would involve genetically transforming the bacteria with genes that produce effector molecules against

malaria parasites ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a verteb ...

inside the malaria mosquito gut. Thorselliaceae can be grown in the laboratory under normal conditions and are related to the bacterium ''

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

'' which suggests that the molecular techniques needed could be similar to those available for ''E. coli''.

References

{{Taxonbar, from=Q19281135 Gammaproteobacteria Gram-negative bacteria Bacteria genera Enigmatic bacteria taxa