First Defined Media for Leptomonas spp. from Insects*

Abstract

SYNOPSIS. Defined media for Leptomonas collosoma, L. mirabilis, and L. sp. from Dysdercus are described. In addition to factors required by Crithidia spp., including a source of Crithidia factor, all 3 organisms require glycine. Leptomonas collosoma and L. sp. from Dysdercus require choline. All trypanosomatids thus far studied require calcium pantothenate but L. collosoma has an especially large requirement. Leptomonas mirabilis but not L. sp. from Dysdercus can synthesize methionine from homocysteine thiolactone during growth. Homocysteine thiolactone is toxic to L. sp. from Dysdercus. Methionine plus vitamin B12 partly annul homocysteine thiolactone toxicity but only if glycine is also present.

Extra Nutritional Requirements of Artificially Aposymbiotic Crithidia deanei*

“…The nutritional requiremcnts of the aposymbiotic C. deanei are similar to those reported for other insect flagellates (5,6,9,10). Resemblance of the synthetic capacity of the aposymbiotic C. deanei to that of other insect trypanosomatids may signifiy that many of these flagellates are suitable hosts for symbiotes.…”

Endosymbiosis in trypanosomatids: the genomic cooperation between bacterium and host in the synthesis of essential amino acids is heavily influenced by multiple horizontal gene transfers

“…Histidine is a truly essential amino acid for most trypanosomatids, as corroborated by its obligatory presence in every synthetic media so far devised for regular trypanosomatid growth [22,43,44]. Accordingly, symbiont-harboring and regular trypanosomatid genomes do not seem to carry a single gene for histidine synthesis (Figure 6).…”

“…However, it is well known that these amino acids are essential in defined culture media designed for regular trypanosomatids, but not for symbiont-harboring ones [20,22,43,44]. The biosynthetic routes for these three amino acids use chorismate, which is produced from phosphoenolpyruvate (PEP) via the shikimate pathway, as a common substrate.…”

“…Differently from other members of the family, the urea cycle is complete in symbiont-harboring trypanosomatids by the presence of the OCT gene (EC:2.1.3.3) in symbionts, making these protozoa entirely autotrophic for ornithine, citrulline, and arginine, as previously known from nutritional data [19,22,44,52]. Symbiont-bearing trypanosomatids contain genes for all enzymes leading from glutamate to arginine.…”

Biosynthesis of Vitamins and Cofactors in Bacterium-Harbouring Trypanosomatids Depends on the Symbiotic Association as Revealed by Genomic Analyses

“…The modest number of available cultures of insect trypanosomatids is in part due to the difficulties inherent to growing these organisms in artificial media. This is related to the fastidiousness of insect trypanosomatids, which require nutritionally very rich and complex media in order to grow [2] – [4] . The first defined medium for an insect trypanosomatid was published in 1958 [5] , as an attempt to cultivate Crithidia fasciculata , a species isolated from mosquitoes.…”