Heat shock proteins (HSPs) are molecular chaperones and have an important role in the refolding and degradation of misfolded proteins, and these functions are related to aging. Rotifer is a useful model organism in aging research, owing to small body size (0.1–1 mm), short lifespan (6–14 days), and senescence phenotypes that can be measured relatively easily. Therefore, we used rotifer as a model to determine the role of four typical hsp genes on the aging process in order to provide a better understanding of rotifer aging. We cloned cDNA encoding hsp genes (hsp40, hsp60, hsp70, and hsp90) from the rotifer Brachionus calyciflorus Pallas, analyzed their molecular characteristics, determined its modulatory response under different temperatures and H₂O₂ concentrations and investigated the changes in expression of these genes during the aging process. We found that Bchsp70 mRNA expression significantly decreased with aging. In addition, we also studied the effects of dietary restriction (DR) and vitamin E on rotifer lifespan and reproduction and analyzed the changes in expression of these four Bchsp genes in rotifers treated with DR and vitamin E. The results showed that DR extended the lifespan of rotifers and reduced their fecundity, whereas vitamin E had no significant effect on rotifer lifespan or reproduction. Real-time PCR indicated that DR increased the expression of these four Bchsps. However, vitamin E only improved the expression of Bchsp60, and reduced the expression of Bchsp40, Bchsp70, and Bchsp90. DR pretreatment also increased rotifer survival rate under paraquat-induced oxidative stress. These results indicated that hsp genes had an important role in the anti-aging process.

Length–weight (body length; L _B versus wet weight; W _WT) and chelae length–width (L _Ch versus W _Ch) relationships were determined for male and female crayfish (Procambarus clarkii) under culture conditions. The length–weight relationships for males, females, and total individuals were described as W _WT = 0.014 × , W _WT = 0.020 × , and W _WT = 0.017 × , respectively. This relationship was significantly different (p < 0.001) between males and females. Compared to females, males were heavier and their tail length was shorter (p < 0.001). No statistical difference was observed in mean L _Ch, cheliped length (L _Cp), and W _Ch between the right and left sides within a gender (p > 0.05), but significant differences were detected between males and females (p < 0.001). The regressions for L _Ch versus W _Ch for males and females were W _Ch = 3.083 × and W _Ch = 0.284 × , respectively. This regression differed significantly between males and females; males’ chelae were wider than those of females (p < 0.001). L _Ch, L _Cp, and W _Ch were highly related to L _B; males had longer L _Ch and L _Cp and wider W _Ch than females. Individuals without chelipeds were measured to determine the relationship between the length and body weight (W _BW). The L _B–W _BW relationships for males and females were described as W _BW = 0.074 × and W _BW = 0.033 × respectively. Females exhibited positive allometric growth (b > 3), and males showed negative allometric growth (b < 3). No statistical difference was observed in mean W _BW between males and females when L _B was used as a covariate (p > 0.05).

The effects of acute ammonia exposure on juvenile Macrobrachium nipponense (De Haan, 1849) were evaluated. The ${\rm{L}}{{\rm{C}}_{{\rm{50}}}}$ values