PBAN/pyrokinin peptides in the central nervous system of the fire ant, Solenopsis invicta

Abstract

The pyrokinin/pheromone-biosynthesis-activating neuropeptide (PBAN) family of peptides found in insects is characterized by a 5-amino-acid C-terminal sequence, FXPRLamide. The pentapeptide is the active core required for diverse physiological functions, including the stimulation of pheromone biosynthesis in female moths, muscle contraction, induction of embryonic diapause, melanization, acceleration of puparium formation, and termination of pupal diapause. We have used immunocytochemical techniques to demonstrate the presence of pyrokinin/PBAN-like peptides in the central nervous system of the fire ant, Solenopsis invicta. Polyclonal antisera against the C-terminal end of PBAN have revealed the location of the peptide-producing cell bodies and axons in the central nervous system. Immunoreactive material is detectable in at least three groups of neurons in the subesophageal ganglion and corpora cardiaca of all adult sexual forms. The ventral nerve cord of adults consists of two segmented thoracic ganglia and four segmented abdominal ganglia. Two immunoreactive pairs of neurons are present in the thoracic ganglia, and three neuron pairs in each of the first three abdominal ganglia. The terminal abdominal ganglion has no immunoreactive neurons. PBAN immunoreactive material found in abdominal neurons appears to be projected to perisympathetic organs connected to the abdominal ganglia. These results indicate that the fire ant nervous system contains pyrokinin/PBAN-like peptides, and that these peptides are released into the hemolymph. In support of our immunocytochemical results, significant pheromonotropic activity is found in fire ant brain-subesophageal ganglion extracts from all adult fire ant forms (queens, female and male alates, and workers) when extracts are injected into decapitated females of Helicoverpa zea. This is the first demonstration of the presence of pyrokinin/PBAN-like peptides and pheromonotropic activity in an ant species.

Identification and Expression of Capa Gene in the Fire Ant, Solenopsis invicta

“…This absence raised questions about possible compensation of functions of CAPA peptides. In previous studies on S. invicta [5], [30], distinct PK/PBAN immunoreactivity was observed in abdominal ganglia and associated PSOs. However, pk/pban -mRNA transcription was not detectable in these tissues (see also Fig.…”

Pyrokinin/PBAN-like peptides in the central nervous system of mosquitoes

“…A similar two gene expression pattern for PK/PBAN-like peptides has been proposed for Solenopsis sp. (Choi et al 2009), Manduca sexta (Loi and Tublitz 2004), Bombyx mori (Roller et al 2008), and Periplaneta americana (Predel and Eckert 2000;Schoofs et al 1992). A search of the Anopholes gambiae genome indicates that these same two genes putatively code for peptides in the PK/PBAN family (Riehle et al 2002) The PKs produced by capa and hugin have been confirmed by mass spectroscopy in the mosquito A. aegypti (Predel et al 2010).…”

Differences in sNPF Receptor-Expressing Neurons in Brains of Fire Ant (Solenopsis invicta Buren) Worker Subcastes: Indicators for Division of Labor and Nutritional Status?

“…In different insect species including social insects several neuropeptides had been detected in the SEG, such as FMRFamide-like peptides, FXPLRamide related peptides (e.g. PBAN), neuropeptide F (NPF) and short neuropeptide F (sNPF) [33], [57], [58]. The expression pattern of the sNPFR in the SEG varies slightly among worker subcastes as shown under results (Figure 6), however, dramatic differences were observed in the SEG when comparing workers from colonies with and without brood (Figure 8).…”