Differential analysis of the haemolymph proteome of Carcinus maenas parasitized by Sacculina carcini (Cirripeda, Rhizocephala) reveals potential mechanisms of parasite control.

Sacculina carcini is an endoparasite of the green crab, Carcinus maenas. This parasite induces behavioural changes in its host and affects its metabolism by inhibiting moulting and reproduction. Using a proteomic approach in mass spectrometry, we studied the haemolymph proteomes of healthy and parasitized wild green crabs from Brittany, France to identify proteins that are differentially expressed as a consequence of parasitization. We also investigated specific proteins involved in reproduction, moulting, and immunity. We detected 77 proteins for females and 53 proteins for males that were differentially present between the healthy and parasitized crabs, some of which were sex-specific. Detection of these differentially expressed proteins suggests that the parasite can inhibit and promote different aspects of the immune response of the host. Sacculina appears to inhibit host melanisation for self-protection, while promoting the presence of immune factors, such as antimicrobial peptides to cope with possible bacterial superinfections. Moreover, one protein, juvenile hormone esterase-like carboxylesterase, was 17-times more abundant in parasitized crabs than in healthy crabs and may be responsible for inhibiting moulting and reproduction in parasitized crabs, thus ensuring the success of Sacculina reproduction.

Oxidative and nutrient stability of a standard rodent spaceflight diet during long-term storage.

The National Aeronautics and Space Administration's standard spaceflight diet for rodents is the nutrient-upgraded rodent food bar (NuRFB). The shelf life of the NuRFB needs to be determined in order to avoid malnutrition of rodents and confounding of research results resulting from nutritional deficiency. The authors compared the oxidative and nutrient stability of NuRFBs stored at either ambient temperature (26 °C) or at refrigeration temperature (4 °C) for use in long-term rodent feeding experiments. After 0, 3, 6, 9 and 12 months (mo) of storage, lipid oxidation, fatty acid composition and amounts of specific vitamins and amino acids in NuRFBs were analyzed. No oxidative rancidity developed in NuRFBs stored at 4 °C for up to 12 mo, but NuRFBs stored at 26 °C for 6 mo developed oxidative rancidity and had reduced amounts of γ-linolenic acid (18:3n-6). Despite loss of vitamin E, vitamin A and thiamin after storage at 26 °C for 12 mo, vitamin levels in NuRFBs remained at or above the levels recommended for optimal rodent health. The amino acid profile of NuRFBs was unaffected by storage at 4 °C or 26 °C for 12 mo. The results suggest that NuRFBs stored at 4 °C for up to 12 mo and NuRFBs stored at 26 °C for up to 6 mo provide suitable nutrition for rodents in long-term experiments.

Evaluation of the nutrient-upgraded rodent food bar for rodent spaceflight experiments.

OBJECTIVE: Selection of an appropriate diet for rodent spaceflight experiments is critical and may have significant effects on mission results. The National Aeronautics and Space Administration (NASA) rodent food bar (RFB) was reformulated and designated as the nutrient-upgraded RFB (NuRFB). The objectives of this study were to determine whether the NuRFB nutrient formulation meets the 1995 National Research Council (NRC) nutrient recommendations and whether the NuRFB can be used for short-term (45-d) and long-term (90-d) spaceflight experiments. METHODS: Nutrient and moisture analyses of the NuRFB were performed. Young (age 13-14 wk) male Sprague-Dawley rats (n=16/group) were individually caged and fed a diet treatment consisting of 1) NuRFB, 2) RFB, or 3) modified AIN-93G containing 4% instead of the 7% fat for 45- or 90-d. At the end of the study, organs were weighted, and serum clinical chemistry indicators of organ function and hematologic measurements were determined. RESULTS: Chemical analysis of the diet ingredients showed that the NuRFB met the 1995 NRC nutrient recommendations for rats. Subsequent animal feeding studies showed that NuRFB was comparable to RFB and modified AIN-93G for supporting rat growth and body weight maintenance. In addition, the safety of the NuRFB for use as a spaceflight diet was indicated by the absence of changes in organ weight or function. CONCLUSION: Based on the study results, the NuRFB performed similarly to the RFB and met the criteria necessary for short-term and long-term rodent spaceflight experiments.