Delay of the egg activation process in the Black Tiger Shrimp Penaeus monodon by manipulation of magnesium levels in spawning water     

Pattira Pongtippatee  Roengsak Luppanakane  Pinij Thaweethamsewee  Pornpimol Kirirat  Wattana Weerachatyanukul  & Boonsirm Withyachumnarnkul 《Aquaculture Research》2010,41(2):227-232

The aim of this study was to determine whether magnesium (Mg²⁺) in seawater is required for egg activation of the black tiger shrimp Penaeus monodon and whether manipulation of Mg²⁺ levels can be used to delay the process and thereby synchronize egg activation. Female P. monodon broodstock were allowed to spawn in artificial seawater containing Mg²⁺ at varying levels with respect to the normal (100%) level: 100%, 50%, 20% and 0%. Egg activation occurred normally at 100% Mg²⁺, incompletely at 50% and 20% Mg²⁺ levels and did not occur at all with 0% Mg²⁺. The fertilization rate with 100% Mg²⁺ was observed to be 83%, but fertilization failed to take place in all the other groups. The fertilization rate was restored from 0% to 76% following the 20% Mg²⁺ level treatment when Mg²⁺ levels returned to normal (100%) as soon as spawning was completed. This study suggests that the level of Mg²⁺ in seawater plays a vital role in P. monodon egg activation, and that commencement of this process could be delayed by manipulation of the Mg²⁺ level during and immediately after spawning.  相似文献   

Physicochemical Properties and Angiotensin I Converting Enzyme Inhibitory Peptides of Freshwater Fish Skin Collagens     

Pornpimol Sungperm  Chompoonuch Khongla 《Journal Of Aquatic Food Product Technology》2020,29(7):650-660

ABSTRACT

The objectives of this study were to characterize physicochemical properties of two collagens, tilapia skin (TS) and hybrid catfish skin (HS). Angiotensin-converting enzyme (ACE) inhibitory peptides from extracted TS and HS collagen using pepsin were also determined. HS collagen had a higher amount of imino acid than TS collagen, while TS contained higher amounts of tyrosine (Tyr) and lysine (Lys). Fourier-transform infrared spectra of both collagens showed predominant helix structure. The HS collagen hydrolysate prepared by pepsin was fractionated using sequential ultrafiltration membranes, and the fraction with molecular weight (MW) <5 kDa showed the highest ACE inhibitory activity (p < .05). After cation exchange and two steps size exclusion chromatography, peptides showed ACE inhibitory activity of 72.06%. This study revealed that ACE inhibitory peptides derived from HS collagen could be developed as a functional food with potential antihypertensive properties.  相似文献   

Isolation and characterisation of crocosin,an antibacterial compound from crocodile (Crocodylus siamensis) plasma     

Sutthidech PREECHARRAM  Pornpimol JEARRANAIPREPAME  Sakda DADUANG  Yosapong TEMSIRIPONG  Theerasak SOMDEE  Tamo FUKAMIZO  Jisnuson SVASTI  Tomohiro ARAKI  Sompong THAMMASIRIRAK 《Animal Science Journal》2010,81(3):393-401

An antibacterial compound from crocodile blood was partially purified and functionally characterised. The freshwater crocodile (Crocodylus siamensis) plasma with antibacterial activity was partially purified by using a centrifugal concentrator and reverse phase high powered liquid chromatography, and designated as crocosin. Crocosin exhibits antibacterial activity toward Salmonella typhi and Staphylococcus aureus. Crocosin is thermostable and resistant to pronase digestion. The structure of crocosin analyzed by mass spectrometry contains repeating units of 94 and 136 m/z. Scanning electron microscopy indicates that crocosin probably penetrates progressively into cytoplasm space, perturbing and damaging bacterial membranes. Crocosin may provide an early defense mechanism toward bacterial infection in freshwater.  相似文献