Crustacean sinus gland (SG) is a well-defined neuroendocrine organ that controls the secretion of various neuropeptides which regulate many physiological activities. The red swamp crayfish Procambarus clarkii is a decapod crustacean with both high economic and scientific importance in China. To facilitate physiological investigations of SG peptide/hormone function in this species, we &nbsp;have been employed tissue extract fractionation by HPLC to obtain a complete description of neuropeptidome and used Electrospray ionization-Fourier transform mass spectrometry (ESI-FTMS) to detect the peptidome present in its organ. In total, 48 peptide sequences belonging to several known neuropeptide families including crustacean cardioactive peptide, CHH precursor-related peptides (CPRPs), orcokinins and pigment dispersing hormones were identified. Among these 48 sequences, 26 are novel peptides and 22 are previously identified. Overall, the results give a stimulus for future physiological studies of SG neuropeptides in P. clarkii and other crustaceans.

Identification of peptides from sinus gland extracts in the red swamp&nbsp;crayfish Procambarus clarkii by mass spectrometry

<div>Background: Red swamp crayfish (Procambarus clarkii) is one of the most economically important farmed aquatic species in China. However, it is also a famous invasive species in the world. 
 
Methods: The present study simulated near current (1970-2000) and future (2030s, 2050s) suitable distribution areas of P. clarkii aquaculture in China under 4 climate scenarios (SSP126, SSP245, SSP370 and SSP585) and screened out the dominant factors affecting the distribution as well, using the MaxEnt model with 60 effective distribution points. 
 
Result: The results showed that mean AUC was 0.986, which indicated a better forecast. The highly suitable aquaculture areas for crayfish were Hubei, Hunan, and Anhui Province. The important environmental factors affecting the distribution of P. clarkii were mean temperature of warmest quarter, precipitation of wettest quarter, isothermality and temperature seasonality. Compared to the present-day predictions, the total area of suitable distribution (general-, medium- and high-suitability) gradually increased in the 2030s and 2050s. The ranking of the total area under different climate change scenarios were SSP370 &gt; SSP585 &gt; SSP126 &gt; SSP245 in the 2030s and SSP585 &gt; SSP370 &gt; SSP126 &gt; SSP245 in the 2050s, indicating that as the greenhouse gas emissions increase, the distribution of P. clarkii was likely to increase. It was of note that the area of high-suitability distribution for SSP585 greatly increased, but for SSP245 greatly decreased in the 2050s. This suggested that we should attach great importance to the ecological risk of crayfish in China and prevent the blind development of the industry.</div>

Identification of peptides from sinus gland extracts in the red swamp crayfish Procambarus clarkii by mass spectrometry

Maxent Model Predictions of Climate Change Impacts on the Suitable Distribution of Crayfish Aquaculture in China