Wang Gui-zhong

Antioxidation and ATPase activity in the gill of mud crab Scylla serrata under cold stress

Mud crab (Scylla serrata) is an important commercial crustacean in China. An experiment was designed to study the effect of cold stress on S. serrata. After a one-week adaptation at 28°C, the temperature is suddenly reduced to 4°C. The crabs were sampled every 2 h for 10 h and dissected immediately to measure the enzyme activity. The crabs at room temperature (28°C) were used as the control group. The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), the content of malondialdehyde (MDA) and the activity of 4 ATPases (Na+,K+-ATPase; Mg2+-ATPase; Ca2+-ATPase; Ca2+,Mg2+-ATPase) were measured biochemically. In contrast to the control group, the SOD activity increased significantly from 2 to 6 h after the cold stress, and then decreased. The CAT and GPX activities increased in 2 h, and then decreased gradually. The content of MDA increased gradually in 4 h. The activity of Na+,K+-ATPase decreased in 2 h, increased up to the top value at Hour 6, then decreased again. The activities of Mg2+-ATPase, Ca2+-ATPase and Ca2+, Mg2+-ATPase increased significantly in 6 h, insignificantly in any other hours. Under cold stress, the activity of antioxidative enzymes in S. serrata was reduced at first then stabilized, ROS-scavenging weakened, and MDA accumulated gradually in the gill after 6 h. The activity of the 4 ATPases in the crab decreased after 6 h, suggesting that the ability to regulate ion concentration has been paralyzed. Therefore, the maximum period to sustain healthy meat in the crab under cold stress is 6 hours.

Status of Biological Studies and Aquaculture Development of the Mud Crab, Scylla serrata, in China: An Experimental Ecological Studies

This is an initial paper in a series of overviews of biological research and aquaculture development of the mud crab, Scylla serrata, in China. Results of experimental ecological studies on mud crabs are reported here. As a result of these experimental studies, results that are important for mud crab culture were also discovered and these include, methods to condition and manage broodstock, determination of ecological conditions that are suitable for embryonic development, and the influence of temperature, salinity, diet and larval density on development and survival of larvae. Results of this work will be useful in establishing a good method for artificial mass culture of larvae.

In vitro study of neuroendocrine regulation over the testicular development in mud crabs Scylla serrata

The reproductive endocrine activities of neuroendocrine organs and androgenic glands (AG) in maleScylla serrata were investigated with co-incubation technology.In vitro studies show that: (1) the AG in Stage III can significantly accelerate the development of seminiferous tubules and spermic maturation; (2) the brain, thoracic ganglia and optic ganglia have no direct influence over the testicular development; (3) the brain and thoracic ganglia can significantly promote the growth of the AG cells and highly significantly boost the ratio of Type B cells, while the optic ganglia have no such effects. It is the first time forin vitro investigations to confirm that the brain and thoracic ganglia can regulate, testicular development through AG in male crustaceans.

Proteomic approach for acute-phase proteins of hemolymph and muscles in Scylla serrata challenged by a pathogenic bacterium

Acute-phase response is documented to be a significant mechanism of innate immunity in vertebrates and invertebrates. In this study, proteomic methodologies were applied for different protein expressions in hemolymph of Scylla serrata challenged by Vibrio parahaemolyticus after immunization, and in muscles of the crabs separately challenged by V. parahaemolyticus, V. anguillarum and Aeromonas hydrophila. Up-regulated cryptocyanin is documented in the hemolymph and up-regulated calexcitin, wingless (fragment) and tachykinin-related peptide in the muscle as acute-phase proteins. All the four altered proteins were responsible for bacterial stress, but cryptocyanin seemed to be a memory response protein against the challenge by a live bacterium after immunization of the live cells. These up-regulated proteins can be indicative of an understanding of immunity of a crab.

Purification and characterization of lectin from humoral fluids of Charybdis feriatus

To search new sources of lectin, an experiment on lectin distribution in humoral serum of crabCharybdis feriatus (in short, CFL) was conducted March, 2002. When adding solid ammonium sulfate into the fluids up to 50% saturation at 4°C, most CFL activity showed precipitates who were then continually extracted by ammonium sulfate of different concentrations. The supernatant, which was called primary CFL fluids, was given a 17.60-fold purification and 45.70% recovery of total activity. Finally, by using Sephadex G-100 column chromatography, the CFL in the primary CFL fluid was highly purified. Compared to the original humoral fluids, the last purified CFL got a 203.90-fold purification and 30.48% recovery of total activity, and demonstrated a single band on SDS-PAGE. In the same time, the purified CFL was detected for agglutination activity with 7 kinds of animal erythrocytes. Other characterization, such as sugar inhibition, and the effect of temperature on the agglutination activity of CFL were also studied. Our results indicate that agglutination activity of CFL was influenced by sugar and temperature.

Immunocytochemical localization of neuropeptide Y,serotonin,substance P and β-endorphin in optic ganglia and brain of Metapenaeus ensis

By using immunocytochemistry method of Strept Avidin-Biotin-Complex, four kinds of antisera raised against rabbits were applied to observe the immunoreactive neurons and neuropils of serotonin (5-HT), neuropeptide Y (NPY), substance P (SP) and β-Endorphin (β-Ep) in optic ganglia and brain ofMetapenaeus ensis. The results showed that, the 5-HT-immunoreactive cells were located in all the four neuropils of optic ganglia. Immunoreactivity of 5-HT was detected in anterior medial protocerebrum neuropils (AMPN), and the inner and outer lateral beside olfactory lobe (OL) of deutocerebrum. The presence of NPY-immunoreactive cells was found in all the four neuropils of the optic ganglia. NPY-immunoreactivity occurred in the anterior median cell cluster, lateral cell cluster of protocerebrum, and cell cluster beside OL and AMPN. SP-immunoreactivity was found in medulla terminalis (MT) of optic ganglia, and lateral cell cluster of protocerebrum and posterior lateral cell cluster of tritocerebrum. β-Ep-immunoreactive cells were in MT only. In conclusion, these specific distribution patterns of the four immunoreactive substances can be used as morphological clues for understanding their different neurophysiological functions.