Changes in tissue structures, rheological properties of cross- and vertical section boiled abalone meat were studied in relation to boiling time. The adductor muscle of abalone Haliotis discus which was removed from t...Changes in tissue structures, rheological properties of cross- and vertical section boiled abalone meat were studied in relation to boiling time. The adductor muscle of abalone Haliotis discus which was removed from the shell, was boiled for 1, 2, and 3 h, respectively. Then it was cut up and separated into cross- and vertical section meat. When observed by a light microscope and a scanning electron microscope, structural changes in the myofibrils were greatest in the cross section meat compared with the vertical section meat. When boiling time was increased from 1 h to 3 h, the instantaneous modulus E 0 and rupture strength of both section meat decreased gradually with increased boiling time, and no significant differences were observed between these two section meat for the same boiling time. When boiled for 1 h, the relaxation time of cross section meat was much longer than that of vertical section meat. There were no significant changes in the relaxation time of vertical section for different boiling time, but the relaxation time of cross section meat was reduced gradually with increasing boiling time. These results confirmed that the difference in rheological properties between the cross- and vertical section meat was mainly due to the denaturation level of myofibrils when heated for 1 h, as well as due to the changes in the amount of denatured proteins, and the manner in which the inner denatured protein components weve exchanged after boiling time was increased from 1 h to 3 h.展开更多
The stability of porphyra-334 in solutions of different pH values at different temperatures was studied. In high acidic conditions, below pH 3, the absorption maximum, λ max, of porphyra-334 shows hypsochromic shift ...The stability of porphyra-334 in solutions of different pH values at different temperatures was studied. In high acidic conditions, below pH 3, the absorption maximum, λ max, of porphyra-334 shows hypsochromic shift towards lower wavelength and the absorbance also has a light decrease. In high alkaline conditions of over pH 12, the absorbance of porphyra-334 decreases and an unknown compound with a peak maximum at 225 nm appears. The peak height of the unknown compound increases with the decrease of absorbance of porphyra-334. This might be related to the decomposition of porphyra-334. At room temperature, porphyra-334 solutions, except high alkaline solutions, are stable. Increasing the temperature, especially higher than 60℃, promotes the decomposition of porphyra-334 and causes the absorbance decrease both in basic and acidic solutions.展开更多
Adenovirus 5 type E1A as a tumor suppressor gene can inhibit tumor growth and enhance the sensitivity of chemotherapy and radiotherapy. E1A have the ability to integrate into the host genome, resulting in long-time ex...Adenovirus 5 type E1A as a tumor suppressor gene can inhibit tumor growth and enhance the sensitivity of chemotherapy and radiotherapy. E1A have the ability to integrate into the host genome, resulting in long-time expres-sion that induces Rb gene inactivation and animal cells im-mortalization. This prompted us to select the E1A protein for treatment of cancer in order to overcome the limitations of E1A gene therapy. Thus, we firstly constructed E1A eu-caryotic expression vector (pPIC9/E1A), transformated the pichia pastoris yeast cells (GS115) and screened the high-expressing recombinant strains. The positive yeast strains were cultured in the shake flask, and induced for 3 d. The crude E1A protein was purified using two steps of col-umn chromatography on HiTrap Q and HiTrap SP. The pu-rified E1A protein was identified by SDS-PAGE and Western blot. E1A protein was mostly located at cellular nuclear when Chariot delivered E1A protein into cells. The analysis in vitro indicated that the E1A protein arrested LN686 cell cycle at G2/M phase, and significantly inhibited the growth of LN686 tumor cells. The current studies firstly provided an experimental basis to further develop E1A protein for tumor treatment.展开更多
文摘Changes in tissue structures, rheological properties of cross- and vertical section boiled abalone meat were studied in relation to boiling time. The adductor muscle of abalone Haliotis discus which was removed from the shell, was boiled for 1, 2, and 3 h, respectively. Then it was cut up and separated into cross- and vertical section meat. When observed by a light microscope and a scanning electron microscope, structural changes in the myofibrils were greatest in the cross section meat compared with the vertical section meat. When boiling time was increased from 1 h to 3 h, the instantaneous modulus E 0 and rupture strength of both section meat decreased gradually with increased boiling time, and no significant differences were observed between these two section meat for the same boiling time. When boiled for 1 h, the relaxation time of cross section meat was much longer than that of vertical section meat. There were no significant changes in the relaxation time of vertical section for different boiling time, but the relaxation time of cross section meat was reduced gradually with increasing boiling time. These results confirmed that the difference in rheological properties between the cross- and vertical section meat was mainly due to the denaturation level of myofibrils when heated for 1 h, as well as due to the changes in the amount of denatured proteins, and the manner in which the inner denatured protein components weve exchanged after boiling time was increased from 1 h to 3 h.
基金supported by the Natural Science Foundation of Qingdao(No.04-2-JZ-110).
文摘The stability of porphyra-334 in solutions of different pH values at different temperatures was studied. In high acidic conditions, below pH 3, the absorption maximum, λ max, of porphyra-334 shows hypsochromic shift towards lower wavelength and the absorbance also has a light decrease. In high alkaline conditions of over pH 12, the absorbance of porphyra-334 decreases and an unknown compound with a peak maximum at 225 nm appears. The peak height of the unknown compound increases with the decrease of absorbance of porphyra-334. This might be related to the decomposition of porphyra-334. At room temperature, porphyra-334 solutions, except high alkaline solutions, are stable. Increasing the temperature, especially higher than 60℃, promotes the decomposition of porphyra-334 and causes the absorbance decrease both in basic and acidic solutions.
文摘Adenovirus 5 type E1A as a tumor suppressor gene can inhibit tumor growth and enhance the sensitivity of chemotherapy and radiotherapy. E1A have the ability to integrate into the host genome, resulting in long-time expres-sion that induces Rb gene inactivation and animal cells im-mortalization. This prompted us to select the E1A protein for treatment of cancer in order to overcome the limitations of E1A gene therapy. Thus, we firstly constructed E1A eu-caryotic expression vector (pPIC9/E1A), transformated the pichia pastoris yeast cells (GS115) and screened the high-expressing recombinant strains. The positive yeast strains were cultured in the shake flask, and induced for 3 d. The crude E1A protein was purified using two steps of col-umn chromatography on HiTrap Q and HiTrap SP. The pu-rified E1A protein was identified by SDS-PAGE and Western blot. E1A protein was mostly located at cellular nuclear when Chariot delivered E1A protein into cells. The analysis in vitro indicated that the E1A protein arrested LN686 cell cycle at G2/M phase, and significantly inhibited the growth of LN686 tumor cells. The current studies firstly provided an experimental basis to further develop E1A protein for tumor treatment.
