The cockroachBlattella germanicaobtains nitrogen from uric acid through a metabolic pathway shared with its bacterial endosymbiont

Abstract

Uric acid stored in the fat body of cockroaches is a nitrogen reservoir mobilized in times of scarcity. The discovery of urease in Blattabacterium cuenoti , the primary endosymbiont of cockroaches, suggests that the endosymbiont may participate in cockroach nitrogen economy. However, bacterial urease may only be one piece in the entire nitrogen recycling process from insect uric acid. Thus, in addition to the uricolytic pathway to urea, there must be glutamine synthetase assimilating the released ammonia by the urease reaction to enable the stored nitrogen to be metabolically usable. None of the Blattabacterium genomes sequenced to date possess genes encoding for those enzymes. To test the host's contribution to the process, we have sequenced and analysed Blattella germanica transcriptomes from the fat body. We identified transcripts corresponding to all genes necessary for the synthesis of uric acid and its catabolism to urea, as well as for the synthesis of glutamine, asparagine, proline and glycine, i.e. the amino acids required by the endosymbiont. We also explored the changes in gene expression with different dietary protein levels. It appears that the ability to use uric acid as a nitrogen reservoir emerged in cockroaches after its age-old symbiotic association with bacteria.

Dietary choice for a balanced nutrient intake increases the mean and reduces the variance in the reproductive performance of male and female cockroaches

“…; Patiño‐Navarrete et al. ). In our experiment, cockroaches were fed commercial rat chow, which contains relatively large amounts of crude P (~20%), during their juvenile development.…”

“…First, this may represent an adaptation to maintain nutritional homeostasis in cockroaches. Most cockroach species, including N. cinerea (Kambhampati et al 2013), harbor endosymbiotic bacteria (Blattabacterium) within specialized cells in the fat body that enable them to store nitrogen as uric acid during times of excess P and recycle the nitrogen for amino acids when P is limited in the diet (Sabree et al 2009;Patiño-Navarrete et al 2014). In our experiment, cockroaches were fed commercial rat chow, which contains relatively large amounts of crude P (~20%), during their juvenile development.…”

A novel intracellular mutualistic bacterium in the invasive antCardiocondyla obscurior

“…Nutrient-providing symbionts are commonly found in hosts with restricted diets, for example, aphids feeding on phloem sap (Baumann, 2005), blood-feeding diptera (Wang et al, 2013) or grain weevils (Heddi et al, 1999). Symbionts can provide essential amino acids, vitamins or help in nitrogen recycling (Nakabachi et al, 2005;Feldhaar et al, 2007;Michalkova et al, 2014;Patino-Navarrete et al, 2014). Such bacteria are commonly harbored in bacteriocytes, specialized host cells that sometimes form special organ-like structures, the bacteriomes (Baumann, 2005) or are confined to the insect gut (Engel and Moran, 2013).…”

The mycobiota of the sand fly Phlebotomus perniciosus: Involvement of yeast symbionts in uric acid metabolism

“…In particular, Patiño‐Navarrete et al . () demonstrated that in the cockroach Blattella germanica the nitrogen recycling pathway is chimeric, with participation of enzymes from the host and the bacterial symbiont B. cuenoti .…”