• 한국양식학회지
• /
• 제17권4호
• /
• pp.246-250
• /
• 2004

Survival of 12.7 g (average body weight) Litopenaeus vannamei was examined at temperatures of 14, 16, 18, 28, 32, 34 and 36$^{\circ}C$ and salinities of l0, 20, 30 and 40 ppt after 7 days. Hemolymph osmolality was measured at 12 combinations of salinities (l0, 20, 30 and 40 ppt) and temperature levels (18, 28 and 34$^{\circ}C$) after 14 days. The results show that the species have their best survival between temperatures of 18 and 3$0^{\circ}C$ and salinity above 20 ppt. Hemolymph osmolality increased with increased salinity at all temperatures tested. The isosmotic point calculated from the linear relationship between hemolymph osmolality and medium osmolality and recorded as 826, 809 and 1,117 mOsm/kg which is equivalent to 29.4, 28.8 and 40.2 ppt at 18, 28 and 34$^{\circ}C$, respectively. The slopes obtained from the relationship between hemolymph osmolality and medium osmolality were 0.314, 0.276 and 0.541 for L. vannamei at 18, 28 and 34$^{\circ}C$, respectively, suggesting that the shrimp at 34$^{\circ}C$ regulated osmotic concentration much worse than those at 18 and 28$^{\circ}C$. This result also indicated that L. vannamei living at 34$^{\circ}C$, showed more fluctuation in hemolymph osmolality than those at 18 and 28$^{\circ}C$.

• 한국양식학회지
• /
• 제20권4호
• /
• pp.205-211
• /
• 2007

Stress-inducible proteins may function in part as molecular chaperones, protecting cells from damage due to various stresses and helping to maintain homeostasis. We examined the mRNA expression patterns of a 68-kDa heat shock protein (HSP68) and 78-kDa glucose-regulated protein (GRP78) in relation to physiological changes in Pacific oyster Crassostrea gigas under osmotic stress. Expression of HSP68 and GRP78 mRNA in the gill significantly increased until 48 h in a hypersaline environment (HRE) and 72 h in a hyposaline environment (HOE), and then decreased. Osmolality and the concentrations of $Na^+$, $Cl^-$, and $Ca^{2+}$ in the hemolymph of HRE oysters significantly increased until 72 h (the highest value) and then gradually decreased; in HOE oysters, these values significantly decreased until 72 h (the lowest value), and then increased. These results suggest that osmolality and $Na^+$, $Cl^-$, and $Ca^{2+}$ concentrations were stabilized by HSP68 and GRP78, and indicate that these two stress-induced proteins play an important role in regulating the metabolism and protecting the cells of the Pacific oysters exposed to salinity changes.

• 한국수산과학회지
• /
• 제54권5호
• /
• pp.761-768
• /
• 2021

This study was carried out to identify an effective method to acclimate low-salinity (4 psu) bred Litopenaeus vannamei (mean body weight 16±3.3 g) to sea water. The fast acclimation group (FA) was directly exposed to filtered sea water (32 psu) while the slow acclimation group (SA) was exposed to a slow increase in salinity. Shrimps were sampled at 0, 1, 3, 6, 12, 24 and 48 h for plasma analyses. The plasma components between experimental groups did not show significant differences. The hemolymph osmolality (HO) in FA increased significantly after 1 h (P<0.05), while in SA it started to increase slowly only at 24 h and reached a similar level to that of FA at 48 h. The levels of Na⁺ and Mg²⁺ ions were significantly different between the two treatments (P<0.05), but there was no significant difference in Ca²⁺ ion levels. We found that the different methods of acclimation of L. vannamei to sea water do not affect the plasma components significantly, but lead to changes in the HO and ion levels, it is considerable to acclimate gradually for at least two days.

• 한국응용곤충학회지
• /
• 제36권3호
• /
• pp.256-263
• /
• 1997

담배거세미나방(Spodoptera litura Fabricius)의 체내빙결점과 내한성이 검정되었다. 체내빙결점은 발육시기에 따라 다양했다. 알(약 -$27^{\circ}C$)이 가장 낮았고 용과 성충(약 $-18^{\circ}C$)이 다음이었으며 유충이 (-1$0^{\circ}C$~-$16^{\circ}C$) 가장 높은 온도를 기록했다. 유충의 체내빙결점은 유충의 영기가 진행함에 따라 상승했다. 각 발육단계의 치사저온온도는 각자의 체내빙결점보다 높았다. 알과 유충을 아치사온도에 미리 노출시킴으로서 치사온도에 대한 생존력을 높였다. 아치사온도는 또한 5령충의 혈림프 삼투압을 증가시켰으며 저온에 특이적인 단백질들(20과 27kD)을 발현하게 했다. 이상의 결과는 이 해충이 동결감수성 곤충류에 속함을 나타낸다.