Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its t...Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its toxicity are very few.This study investigated the toxicity of the O.cf.ovata(TIO991)isolated from Weizhou Island in the South China Sea by using methanol and chloroform to extract toxic compounds from the algal cells cultured indoor.Experiments on mouse acute toxicity showed that the crude methanol extract(CME)of O.cf.ovata caused the death of mice in 16–18 min.Furthermore,CME inhibited the cell reproduction of human neuroblastoma cells(BE(2)-M17 cells)by Cell Counting Kit-8 with a dose-and time-effect relationship and caused cell death in the form of cell necrosis.We found that CME had strong hemolytic activity and was significantly inhibited by ouabain,indicating that CME might contain palytoxins.By contrast,the crude chloroform extract of O.cf.ovata was relatively weak in toxicity as obtained in our experiments on mouse acute toxicity,cytotoxicity,and hemolytic activity.This suggests that the algae may raise the potential threat to marine ecosystems and public health.展开更多
Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xan...Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xanthorrhiza Roxb.Methods: The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy. Agar-well diffusion assay was used to study the antimicrobial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration(MIC) against four bacterial strains and yeast.Results: The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly(88.53%) in the rhizome oil of Curcuma cf. xanthorrhiza. Sesquiterpenes(50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes(45.55%) and sesquiterpenes(45.81%) were found in C. aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor(29.39%) and germacrone(21.21%). Germacrone(15.76%), b-pinene(9.97%)and camphor(9.96%) were found as major compounds in the rhizome oils of C. glans while a-terpinolene(24.86%) and p-cymen-7-ol(12.17%) were found as major compositions in Curcuma cf. xanthorrhiza. The essential oils were tested against four bacterial strains and yeast. As a result, the rhizome oil of C. aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone(21.94 ± 0.24) mm, MIC 125 μg/mL],Bacillus cereus [inhibition zone(20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans [inhibition zone(11.60 ± 0.30) mm, MIC 250 μg/mL].Conclusions: The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria(Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria(Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a potential source of natural antimicrobial substances.展开更多
Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which th...Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which the siliceous organisms form,is an important component of the marine biological pump.It is crucial to the study of the operational mechanisms of biological pump with different sea areas.Moreover,it is the key link to the study of global silicon cycle.This paper introduces the basic mechanism of the formation of diatom silica walls and a new way of researching silicic acid metabolism,namely the 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)-methoxy)phenyl)oxazole(PDMPO) dyeing method.Under a fluorescence microscope after excitation with bright green fluorescence,it can combine with silicic acid to form a complex into the Si deposition within diatom cells.The advantage of this method is that it can monitor the metabolism of silicate after adding PDMPO.For experimentation and sample collection in each of the specified time points,samples were determinated through the unutilized silicic acid,silica dissoluble intracellular and Si deposition within diatom cells,not only using hot alkaline digestions method but also PDMPO dyeing method.Results showed a good linear relationship between PDMPO fluorescent value and biogenic silica concentration.It was also indicated that PDMPO had no deleterious impact on Skeletonema cf.costatum growth for 34 h and was useful for tracking newly-deposited biogenic silica in diatoms' frustules.展开更多
Several species of the fungal genus Trichoderma establish biological interactions with various micro- and macro-organisms. Some of these interactions are relevant in ecological terms and in biotechnological applicatio...Several species of the fungal genus Trichoderma establish biological interactions with various micro- and macro-organisms. Some of these interactions are relevant in ecological terms and in biotechnological applications, such as biocontrol, where Trichoderma could be considered as an invasive species that colonizes a recipient community. The success of this invasion depends on multiple factors, which can be assayed using experimental communities as study models. Therefore, the aim of this work is to develop a species-specific sequence-characterized amplified region （SCAR） marker to monitor the colonization and growth of T. cf. harzianum when it invades experi- mental communities. For this study, 16 randomly amplified polymorphic DNA （RAPD） primers of 10-mer were used to generate polymorphic patterns, one of which generated a band present only in strains of T. cf. harzianum. This band was cloned, sequenced, and five primers of 20-23 mer were designed. Primer pairs 2F2/2R2 and 2F2/2R3 successfully and specifically amplified fragments of 278 and 448 bp from the T. cf. harzianum BpT10a strain DNA, respectively. Both primer pairs were also tested against the DNA from 14 strains of T. cf. harzianum and several strains of different fungal genera as specificity controls. Only the DNA from the strains of T. cf. hat-zianum was successfully amplified. Moreover, primer pair 2F2/2R2 was assessed by quantitative real-time polymerase chain reaction （PCR） using fungal DNA mixtures and DNA extracted from fungal experimental communities as templates. T. cf. harzianum was detectable even when as few as 100 copies of the SCAR marker were available or even when its population represented only 0.1% of the whole community.展开更多
基金Supported by the Special Research for the Science and Technology Basic Resources Investigation Program of China(No.2018FY100200)the National Natural Science Foundation of China(No.42176206)the Natural Science Foundation of Shandong Province(No.ZR2021MD071)。
文摘Ostreopsis cf.ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds.The existence of O.cf.ovata has been found in the Chinese coastal areas,but studies on its toxicity are very few.This study investigated the toxicity of the O.cf.ovata(TIO991)isolated from Weizhou Island in the South China Sea by using methanol and chloroform to extract toxic compounds from the algal cells cultured indoor.Experiments on mouse acute toxicity showed that the crude methanol extract(CME)of O.cf.ovata caused the death of mice in 16–18 min.Furthermore,CME inhibited the cell reproduction of human neuroblastoma cells(BE(2)-M17 cells)by Cell Counting Kit-8 with a dose-and time-effect relationship and caused cell death in the form of cell necrosis.We found that CME had strong hemolytic activity and was significantly inhibited by ouabain,indicating that CME might contain palytoxins.By contrast,the crude chloroform extract of O.cf.ovata was relatively weak in toxicity as obtained in our experiments on mouse acute toxicity,cytotoxicity,and hemolytic activity.This suggests that the algae may raise the potential threat to marine ecosystems and public health.
基金supported by the grants from the Biodiversity-Based Economy Development Office Public Organization -National Research Council of Thailand(Grant number.R000012298)Department of Pharmaceutical Sciences,the Faculty of Pharmacy and the Graduate School,Chiang Mai University,Chiang Mai,Thailand
文摘Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xanthorrhiza Roxb.Methods: The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy. Agar-well diffusion assay was used to study the antimicrobial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration(MIC) against four bacterial strains and yeast.Results: The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly(88.53%) in the rhizome oil of Curcuma cf. xanthorrhiza. Sesquiterpenes(50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes(45.55%) and sesquiterpenes(45.81%) were found in C. aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor(29.39%) and germacrone(21.21%). Germacrone(15.76%), b-pinene(9.97%)and camphor(9.96%) were found as major compounds in the rhizome oils of C. glans while a-terpinolene(24.86%) and p-cymen-7-ol(12.17%) were found as major compositions in Curcuma cf. xanthorrhiza. The essential oils were tested against four bacterial strains and yeast. As a result, the rhizome oil of C. aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone(21.94 ± 0.24) mm, MIC 125 μg/mL],Bacillus cereus [inhibition zone(20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans [inhibition zone(11.60 ± 0.30) mm, MIC 250 μg/mL].Conclusions: The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria(Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria(Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a potential source of natural antimicrobial substances.
基金The National Natural Science Foundation of China primarily supported this studyDr.J.Sun received grants from the National Natural Science Foundation of China(Nos.41276124 and 41676112)+2 种基金Program for Changjiang Scholars and the Science Fund for University Creative Research Groups in Tianjin(No.TD12-5003)Dr.Y.Feng received grants from the National Natural Science Foundation of China(No.41306118)Dr.G.Zhang received grants from the Foundation of Tianjin Key Laboratory of Marine Resources and Chemistry(Tianjin University of Science&Technology),P.R.China(No.201504)
文摘Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which the siliceous organisms form,is an important component of the marine biological pump.It is crucial to the study of the operational mechanisms of biological pump with different sea areas.Moreover,it is the key link to the study of global silicon cycle.This paper introduces the basic mechanism of the formation of diatom silica walls and a new way of researching silicic acid metabolism,namely the 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)-methoxy)phenyl)oxazole(PDMPO) dyeing method.Under a fluorescence microscope after excitation with bright green fluorescence,it can combine with silicic acid to form a complex into the Si deposition within diatom cells.The advantage of this method is that it can monitor the metabolism of silicate after adding PDMPO.For experimentation and sample collection in each of the specified time points,samples were determinated through the unutilized silicic acid,silica dissoluble intracellular and Si deposition within diatom cells,not only using hot alkaline digestions method but also PDMPO dyeing method.Results showed a good linear relationship between PDMPO fluorescent value and biogenic silica concentration.It was also indicated that PDMPO had no deleterious impact on Skeletonema cf.costatum growth for 34 h and was useful for tracking newly-deposited biogenic silica in diatoms' frustules.
基金Project supported by the Chilean National Fund for Scientific and Technological Development(FONDECYT)(No.1120508)
文摘Several species of the fungal genus Trichoderma establish biological interactions with various micro- and macro-organisms. Some of these interactions are relevant in ecological terms and in biotechnological applications, such as biocontrol, where Trichoderma could be considered as an invasive species that colonizes a recipient community. The success of this invasion depends on multiple factors, which can be assayed using experimental communities as study models. Therefore, the aim of this work is to develop a species-specific sequence-characterized amplified region （SCAR） marker to monitor the colonization and growth of T. cf. harzianum when it invades experi- mental communities. For this study, 16 randomly amplified polymorphic DNA （RAPD） primers of 10-mer were used to generate polymorphic patterns, one of which generated a band present only in strains of T. cf. harzianum. This band was cloned, sequenced, and five primers of 20-23 mer were designed. Primer pairs 2F2/2R2 and 2F2/2R3 successfully and specifically amplified fragments of 278 and 448 bp from the T. cf. harzianum BpT10a strain DNA, respectively. Both primer pairs were also tested against the DNA from 14 strains of T. cf. harzianum and several strains of different fungal genera as specificity controls. Only the DNA from the strains of T. cf. hat-zianum was successfully amplified. Moreover, primer pair 2F2/2R2 was assessed by quantitative real-time polymerase chain reaction （PCR） using fungal DNA mixtures and DNA extracted from fungal experimental communities as templates. T. cf. harzianum was detectable even when as few as 100 copies of the SCAR marker were available or even when its population represented only 0.1% of the whole community.
