Harmful algal blooms （HABs） can occur and then disappear quickly, corresponding to consistent growing and declining of heavy biomasses. The molecular mechanism of blooming remains unclear. In this study, calmodulin ...Harmful algal blooms （HABs） can occur and then disappear quickly, corresponding to consistent growing and declining of heavy biomasses. The molecular mechanism of blooming remains unclear. In this study, calmodulin gene （cam） of HAB causing species Alexandrium catenella was isolated and characterized, The expression of calmodulin gene was profiled at different growth rates and in heat stress. The full cDNA of cam was 597 nucleotides （nt） in length, including a 25 nt 5＇ untranslated region （UTR）, an 122nt 3＇ UTR, and a 450nt open reading frame （ORF） encoding 149 amino acids. The deduced calmodulin （CAM） was highly conserved in comparison with those of other organisms. As was determined with real-time RT PCR, the abundance of cam transcript varied in a pattern similar to cell growth rate during the whole growing period. The abundance of cam transcript increased by more than 8 folds from lag growth phase to exponential growth phase, and then obviously decreased from exponential growth phase to stationary/decline growth phase. In addition, the relative abundance of cam transcript significantly declined with time during heat shock. Taking CaM function described in other organisms into account, we believe that Ca2- -involved signal transduction, methyla- tion of DNA and toxin precursors underlined the cell growth of this species. The response of cam gene to heat stress in dinoflagellate suggested restrictions in Ca2＋ signal transduction and methylation. These findings are helpful to understand the relationships among growth, cell signal transduction, bloom formation and interaction with environmental stimuli in dinoflagellates.展开更多
Light and temperature signals are the most important environmental cues regulating plant growth and development. Plants have evolved various strategies to prepare for, and adapt to environmental changes. Plants integr...Light and temperature signals are the most important environmental cues regulating plant growth and development. Plants have evolved various strategies to prepare for, and adapt to environmental changes. Plants integrate environmental cues with endogenous signals to regulate various physiological processes, including flowering time. There are at least five distinct pathways controlling flowering in the model plant Arabidopsis thaliana: the photoperiod pathway, the vernalization/thermosensory pathway, the autonomous floral initiation, the gibberellins pathway, and the age pathway. The photoperiod and temperature/vernalization pathways mainly perceive external signals from the environment, while the autonomous and age pathways transmit endogenous cues within plants. In many plant species, floral transition is precisely controlled by light signals(photoperiod) and temperature to optimize seed production in specific environments. The molecular mechanisms by which light and temperature control flowering responses have been revealed using forward and reverse genetic approaches. Here we focus on the recent advances in research on flowering responses to light and temperature.展开更多
Acoustic interference can impede effective communication that is important for survival and reproduction of animals. In response to acoustic interference, some animals can improve signalling efficacy by altering the s...Acoustic interference can impede effective communication that is important for survival and reproduction of animals. In response to acoustic interference, some animals can improve signalling efficacy by altering the structure of their signals. In this study, we played artificial noise to 46 male spring peepers Pseudacris crucifer, on their breeding grounds, and tested whether the noise affected the duration, call rate, and peak frequency of their advertisement calls. We used two experimental noise treatments that masked either the high- or low-frequency components of an average advertisement call; this allowed us to evaluate whether frogs adaptively shift the peak frequency of their calls away from both types of interference. Our playback treatments caused spring peepers to produce shorter calls, and the high-frequency noise treatment caused them to lower the frequency of their calls immediately after the noise ceased. Call rate did not change in response to playback. Consistent with previous studies, ambient temperature was inversely related to call duration and positively related to call rate. We conclude that noise affects the structure of spring peeper advertisement calls, and that spring peepers therefore have a mechanism for altering signal structure in response to noise. Future studies should test if other types of noise, such as biotic or anthropogenic noise, have similar effects on call structure, and if the observed changes to call structure enhance or impair communication in noisy environments [Current Zoology 60 （4）： 438-448, 2014].展开更多
文摘Harmful algal blooms （HABs） can occur and then disappear quickly, corresponding to consistent growing and declining of heavy biomasses. The molecular mechanism of blooming remains unclear. In this study, calmodulin gene （cam） of HAB causing species Alexandrium catenella was isolated and characterized, The expression of calmodulin gene was profiled at different growth rates and in heat stress. The full cDNA of cam was 597 nucleotides （nt） in length, including a 25 nt 5＇ untranslated region （UTR）, an 122nt 3＇ UTR, and a 450nt open reading frame （ORF） encoding 149 amino acids. The deduced calmodulin （CAM） was highly conserved in comparison with those of other organisms. As was determined with real-time RT PCR, the abundance of cam transcript varied in a pattern similar to cell growth rate during the whole growing period. The abundance of cam transcript increased by more than 8 folds from lag growth phase to exponential growth phase, and then obviously decreased from exponential growth phase to stationary/decline growth phase. In addition, the relative abundance of cam transcript significantly declined with time during heat shock. Taking CaM function described in other organisms into account, we believe that Ca2- -involved signal transduction, methyla- tion of DNA and toxin precursors underlined the cell growth of this species. The response of cam gene to heat stress in dinoflagellate suggested restrictions in Ca2＋ signal transduction and methylation. These findings are helpful to understand the relationships among growth, cell signal transduction, bloom formation and interaction with environmental stimuli in dinoflagellates.
基金supported by the National Natural Science Foundation of China(3132200631270285)the Hundred Talents Program of the Chinese Academy of Sciences
文摘Light and temperature signals are the most important environmental cues regulating plant growth and development. Plants have evolved various strategies to prepare for, and adapt to environmental changes. Plants integrate environmental cues with endogenous signals to regulate various physiological processes, including flowering time. There are at least five distinct pathways controlling flowering in the model plant Arabidopsis thaliana: the photoperiod pathway, the vernalization/thermosensory pathway, the autonomous floral initiation, the gibberellins pathway, and the age pathway. The photoperiod and temperature/vernalization pathways mainly perceive external signals from the environment, while the autonomous and age pathways transmit endogenous cues within plants. In many plant species, floral transition is precisely controlled by light signals(photoperiod) and temperature to optimize seed production in specific environments. The molecular mechanisms by which light and temperature control flowering responses have been revealed using forward and reverse genetic approaches. Here we focus on the recent advances in research on flowering responses to light and temperature.
文摘Acoustic interference can impede effective communication that is important for survival and reproduction of animals. In response to acoustic interference, some animals can improve signalling efficacy by altering the structure of their signals. In this study, we played artificial noise to 46 male spring peepers Pseudacris crucifer, on their breeding grounds, and tested whether the noise affected the duration, call rate, and peak frequency of their advertisement calls. We used two experimental noise treatments that masked either the high- or low-frequency components of an average advertisement call; this allowed us to evaluate whether frogs adaptively shift the peak frequency of their calls away from both types of interference. Our playback treatments caused spring peepers to produce shorter calls, and the high-frequency noise treatment caused them to lower the frequency of their calls immediately after the noise ceased. Call rate did not change in response to playback. Consistent with previous studies, ambient temperature was inversely related to call duration and positively related to call rate. We conclude that noise affects the structure of spring peeper advertisement calls, and that spring peepers therefore have a mechanism for altering signal structure in response to noise. Future studies should test if other types of noise, such as biotic or anthropogenic noise, have similar effects on call structure, and if the observed changes to call structure enhance or impair communication in noisy environments [Current Zoology 60 （4）： 438-448, 2014].
