Harmful algal bloom(HAB)is an ecological disaster to local mariculture.At present,its impact on macrophytes has not been well studied.In this study,we cultivated sexually propagated embryos of S argassum fusiformis-an...Harmful algal bloom(HAB)is an ecological disaster to local mariculture.At present,its impact on macrophytes has not been well studied.In this study,we cultivated sexually propagated embryos of S argassum fusiformis-an edible seaweed-in Prorocentrum donghaiense suspensions at different cell densities(0,0.50×10^(5),0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL)for 10 days,during which growth and photosynthetic activities of the embryos were determined,and a monocultivation was set up for comparison.Results show that the relative growth rate and photosynthetic activities of the embryos co-cultivated with P.donghaiense were inhibited mostly and significantly in the cell densities of 0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL,and the inhibitory effects increased in overall with increased cell densities.The maximum relative electron transport rates(rETR max)and apparent photosynthetic efficiency(a)of co-cultivated embryos were all significantly lower than monocultivation ones on the 10 th day.Furthermore,the photosynthetic activity detected by chlorophyll-a fluorescence transient(i.e.,OJIP),the electron transport among electron transfer accepters of PSII(photosystem II)and that from PSII to PSI(photosystem I)was restricted,which is probably responsible for the decreases of rETR max andain the co-cultivated embryos.In addition,parts of the photosynthetic reaction centers of PSII in the co-cultivated embryos were inactivated.Therefore,P.donghaiense bloom could restrain the development and photosynthetic activities of S.fusiformis embryos,reduce the seedlings stock,and eventually hinder the development of S.fusiformis production industry.展开更多
Understanding the embryo physiology of Hizikia fusiformis（Harvey） Okamura will promote the development of artificial seedlings. In this study, H. fusiformis embryos were cultured under different environmental condit...Understanding the embryo physiology of Hizikia fusiformis（Harvey） Okamura will promote the development of artificial seedlings. In this study, H. fusiformis embryos were cultured under different environmental conditions, including different temperatures（15℃, 20℃, and 25℃）, sunlight intensities（100%, 50%, and 25% of full solar radiation） and types of UVR（UV-A and UV-B）. Then, we determined the lengths, maximal quantum yields（ Fv/Fm）, and survival rates of the embryos. The results showed that the embryos had the highest lengths, Fv/Fm values and survival percentages when cultured under a temperature of 20℃ and 25% sunlight intensity. The full level of solar radiation severely reduced the growth and survival ratios of the embryos. Hizikia embryos recovered within 2 h from the damage caused by short-term（30 min） high radiation（about 70% of full solar radiation） and UVR exposure. However, the viabilities of the embryos were significantly decreased after 4 h exposure to UVR. According to these results, we propose that culture conditions with indoor natural light and room temperature would be favorable for the growth, development and physiology of H izikia embryos.展开更多
Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The o...Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The objective of this study was to isolate and characterize lectin activity in Texas Live Oak (Quercus fusiformis). More specifically, the study aimed to determine the lectin’s blood group specificity and pH stability, determine effects of seasonal variation, soil moisture and soil pH on lectin activity. The study also aimed to determine the presence of antifungal activity in Q. fusiformis extracts. Lectin activity was detected and compared via agglutination and protein assays. Protein partial purification was accomplished using diethylaminoethyl ion-exchange chromatography matrix. High Performance Liquid Chromatography (HPLC) was used to assess purity of the lectin. Results showed that Q. fusiformis extracts’ lectin activities are stable at a pH range of 5.2 - 9.2 but with a significant decrease in activity above pH 9.2. The lectin activity was significantly higher when assayed against sheep red blood cells as compared to other blood groups tested. Quercus fusiformis extract is devoid of antifungal activity against Aspergillus niger and Rhizopus stolonifer. The effects of seasonal variation, soil moisture and soil pH do not significantly correlate with lectin activity. Results from HPLC showed presence of three peaks indicating a partial purification of the Q. fusiformis lectin.展开更多
基金Supported by the National Key R&D Program of China(No.2018YFD0901500)the National Natural Science Foundation(Nos.41876124,61871293,41706147,42007372)。
文摘Harmful algal bloom(HAB)is an ecological disaster to local mariculture.At present,its impact on macrophytes has not been well studied.In this study,we cultivated sexually propagated embryos of S argassum fusiformis-an edible seaweed-in Prorocentrum donghaiense suspensions at different cell densities(0,0.50×10^(5),0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL)for 10 days,during which growth and photosynthetic activities of the embryos were determined,and a monocultivation was set up for comparison.Results show that the relative growth rate and photosynthetic activities of the embryos co-cultivated with P.donghaiense were inhibited mostly and significantly in the cell densities of 0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL,and the inhibitory effects increased in overall with increased cell densities.The maximum relative electron transport rates(rETR max)and apparent photosynthetic efficiency(a)of co-cultivated embryos were all significantly lower than monocultivation ones on the 10 th day.Furthermore,the photosynthetic activity detected by chlorophyll-a fluorescence transient(i.e.,OJIP),the electron transport among electron transfer accepters of PSII(photosystem II)and that from PSII to PSI(photosystem I)was restricted,which is probably responsible for the decreases of rETR max andain the co-cultivated embryos.In addition,parts of the photosynthetic reaction centers of PSII in the co-cultivated embryos were inactivated.Therefore,P.donghaiense bloom could restrain the development and photosynthetic activities of S.fusiformis embryos,reduce the seedlings stock,and eventually hinder the development of S.fusiformis production industry.
基金Supported by the Science and Technology Planning Project of Guangdong,China(No.2016A020222001)
文摘Understanding the embryo physiology of Hizikia fusiformis（Harvey） Okamura will promote the development of artificial seedlings. In this study, H. fusiformis embryos were cultured under different environmental conditions, including different temperatures（15℃, 20℃, and 25℃）, sunlight intensities（100%, 50%, and 25% of full solar radiation） and types of UVR（UV-A and UV-B）. Then, we determined the lengths, maximal quantum yields（ Fv/Fm）, and survival rates of the embryos. The results showed that the embryos had the highest lengths, Fv/Fm values and survival percentages when cultured under a temperature of 20℃ and 25% sunlight intensity. The full level of solar radiation severely reduced the growth and survival ratios of the embryos. Hizikia embryos recovered within 2 h from the damage caused by short-term（30 min） high radiation（about 70% of full solar radiation） and UVR exposure. However, the viabilities of the embryos were significantly decreased after 4 h exposure to UVR. According to these results, we propose that culture conditions with indoor natural light and room temperature would be favorable for the growth, development and physiology of H izikia embryos.
文摘Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The objective of this study was to isolate and characterize lectin activity in Texas Live Oak (Quercus fusiformis). More specifically, the study aimed to determine the lectin’s blood group specificity and pH stability, determine effects of seasonal variation, soil moisture and soil pH on lectin activity. The study also aimed to determine the presence of antifungal activity in Q. fusiformis extracts. Lectin activity was detected and compared via agglutination and protein assays. Protein partial purification was accomplished using diethylaminoethyl ion-exchange chromatography matrix. High Performance Liquid Chromatography (HPLC) was used to assess purity of the lectin. Results showed that Q. fusiformis extracts’ lectin activities are stable at a pH range of 5.2 - 9.2 but with a significant decrease in activity above pH 9.2. The lectin activity was significantly higher when assayed against sheep red blood cells as compared to other blood groups tested. Quercus fusiformis extract is devoid of antifungal activity against Aspergillus niger and Rhizopus stolonifer. The effects of seasonal variation, soil moisture and soil pH do not significantly correlate with lectin activity. Results from HPLC showed presence of three peaks indicating a partial purification of the Q. fusiformis lectin.
