Subramanian, Sanjita et al. (2021) International Worm Meeting "Rpamide neuropeptides NLP-22 and NLP-23 mediate egg-laying quiescence during stress induced sleep"

Subramanian, Sanjita, Nelson, Matthew

[International Worm Meeting, 2021]

Sleep is a reversible state in animals, characterized by the inhibition of behaviors that occur periodically during wakefulness. The transitions from wake to sleep states are regulated by signaling pathways that are not fully understood. Caenorhabditis elegans demonstrates a reversible sleep-state following acute exposure to environmental stressors, termed as stress induced sleep (SIS). In adult animals, SIS is characterized by the inhibition of movement, feeding and defecation, and each of these behaviors is largely regulated by neuropeptidergic signaling from the ALA and RIS interneurons. We find that egg-laying behavior, a fundamental process, is also inhibited during SIS. Additionally, we show that egg-laying quiescence (ELQ) is a function of mechanisms that are partially independent of the ALA and RIS. Specifically, RPamide neuropeptides encoded by the genes nlp-22 and nlp-23 signal directly to the terminal structure of the egg-laying circuit, the vulval muscles, to induce ELQ. Our work suggests that signaling from multiple neuropeptidergic neurons is required to inhibit essential behaviors during SIS in C. elegans.

Natesan, Balasubramanian (2010) C. elegans: Development and Gene Expression, EMBL, Heidelberg, Germany "Entomopathogenic nematode Steinernema carpocapsae secreted protease role on host immune suppression"

Natesan, Balasubramanian

[C. elegans: Development and Gene Expression, EMBL, Heidelberg, Germany, 2010]

Entomopathogenic nematode Steinernema carpocapsae secreted protease role on host immune suppression Natesan Bala subramanian, Duarte Toubarro and Nelson Simes CIRN and Department of Biology, University of Azores , 9500-801 Ponta Delgada , Portugal . Steinernema carpocapsae is an entomopathogenic nematode symbiotically associated with the bacterium Xenorhabdus nematophila . This nematode secrete proteases on there secrete products. Proteases are well known catabolic functions and many tasks imposed by a parasitic life cycle. Serine proteases are the most extensively studied enzymes on host parasite interaction. Host defence mechanism including cellular and humoral reactions against invading organisms. In humoral system phenoloxidase is a key enzyme and c onsidering the parasite survival it may inhibit prophenoloxidase system, could be a key to successful parasitism. In order to study host immune suppression, the in fective third-stage (L3) S. carpocapsae nematodes were grown on 1% Galleria mellonella insect homogenate and then collect secretory products (SP). From the SP trypsin (Sc-TRYP) and chymo trypsin (Sc-CHYM) -like serine protease were identified, purified and characterized. I n vitro, 52.6 % and 63.7% prophenoloxidase suppression was observed for Sc-TRYP and Sc-CHYM respectively. Sc-TRYP could affect G. mellonella insect haemocyte causing cells to become spherical or round shape and actin filaments were detected with Phalloidintetramethylrhodamine showed some of them were disorganised in haemocytes. Sc-chym gene expression was analysed with induced and non induced insect homogenate for 6 to72 h. In vivo , purified Sc-CHYM imbibed beads showed, it could prevent haemocytes encapsulation and melanization by 12 and 24 h, respectively. The role of these proteases in host immune suppression will be discussed.