Properties of Pacific white shrimp (Litopenaeus vannamei) collagen and its degradation by endogenous proteinases during cold storage.

Many factors are responsible for the diminished quality of shrimp during cold storage, while the role of collagen has rarely been studied. This study therefore investigated the relationship between collagen degradation and changes of textural properties of Pacific white shrimp, and its hydrolysis by endogenous proteinases. The textural properties of shrimp decreased gradually along with disruption of shrimp muscle tissues, and the chewiness property of shrimp muscle showed a linear relationship with collagen contents in muscle during 6-day-storage at 4 °C.

[Alleviating effect of exogenous melatonin and calcium on the peroxidation damages of cucumber under high temperature stress].

To explore whether there is an interaction between melatonin (MT) and calcium (Ca) in regulating heat tolerance of plants, we analyzed the response of endogenous MT and Ca to heat stress, and examined the effect of MT and Ca on the reactive oxygen (ROS) accumulation, antioxidant system, and transcripts of heat shock factor () and heat shock proteins () of cucumber seedlings under high temperature stress. Seedlings were foliar sprayed with 100 μmol·L MT, 10 mmol·L CaCl, 3 mmol·L ethylene glycol tetraacetic acid (EGTA, Ca chelating agent) +100 μmol·L MT, 0.05 mmol·L chlorpromazine (calmodulin antagonist, CPZ) +100 μmol·L MT, 100 μmol·L p-chlorophenylalanine (p-CPA, inhibitor of MT) +10 mmol·L CaCl or deionized water (HO), respectively.