Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extract...Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extracts as an antibulbing substance,the amount of which was synchronized with the bulb formation.Since allene oxide synthase inhibitor canceled the antibulbing activity ofα-linolenic acid,it was disclosed that jasmonic acid concerns this regulation.Structure-activity-relationship study revealed that its(3R,7S)stereochemistry is necessary for showing its antibulbing activity.It is concluded that(3R,7S)-jasmonate derived fromα-linolenic acid actually participates in the regulation of bulb formation.展开更多
The present work extended the knowledge on the binding and complexation of humic substances(humic acid or fulvic acid) and hematite by Fourier transform infrared spectroscopy(FTIR). The FTIR data gained gave the consi...The present work extended the knowledge on the binding and complexation of humic substances(humic acid or fulvic acid) and hematite by Fourier transform infrared spectroscopy(FTIR). The FTIR data gained gave the consist evidences by two different sampling preparation methods that the interaction mechanism between humic substances and hematite was mainly conform to the ligand exchange involving carboxylic functional groups of humic substances and the surfaces sites of hematite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in this field.展开更多
The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were e...The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.展开更多
Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus...Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus vannamei from two aquaculture patterns(earthen pond and greenhouse)using amino acid automatic analyzer,high-performance liquid chromatography(HPLC),gas chromatography(GC)-ion mobility spectrometry(IMS),and GC-mass spectrometry(GC-MS).The results revealed that dried shrimp from earthen pond had significantly higher free amino acids and 5’-nucleotides than those from greenhouse(P<0.05),and their corresponding equivalent umami concentrations(EUCs)were 23.45 g MSG(100 g)^(−1)and 14.86 g MSG(100 g)^(−1),respectively.For volatile compounds,GC-IMS analysis indicated significant differences in volatile compounds between dried shrimp from different aquaculture patterns.According to the quantitative analysis of GC-MS,11 volatile compounds were identified as aroma-active compounds(AACs),of which six AACs(1-octen-3-ol,3-methylbutanal,nonanal,trimethylamine,2,5-dimethylpyrazine,and 2,3,5-trimethylpyrazine)were found in all dried shrimp samples.Although dried shrimp from greenhouse possesses higher OAVs,OAVs of(E,E)-2,4-nonadienal(fishy smell),and 3,5-diethyl-2-methylpyrazine(burnt smell)reached 171.2 and 333 respectively,imparting negative effects on flavor.In general,dried shrimp from earthen pond had a better flavor profile than those from greenhouse.展开更多
Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was...Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.展开更多
基金Supported by the Naito FoundationGrant-in-Aid for Scientific Research (22K05448)from Japan Society for the Promotion of Science.
文摘Onion plants form spherical bulbs under long-day conditions.Substances regulating bulb formation remain unknown.In the course of chemical studies on the bulb formation,α-linolenic acid was isolated from onion extracts as an antibulbing substance,the amount of which was synchronized with the bulb formation.Since allene oxide synthase inhibitor canceled the antibulbing activity ofα-linolenic acid,it was disclosed that jasmonic acid concerns this regulation.Structure-activity-relationship study revealed that its(3R,7S)stereochemistry is necessary for showing its antibulbing activity.It is concluded that(3R,7S)-jasmonate derived fromα-linolenic acid actually participates in the regulation of bulb formation.
文摘The present work extended the knowledge on the binding and complexation of humic substances(humic acid or fulvic acid) and hematite by Fourier transform infrared spectroscopy(FTIR). The FTIR data gained gave the consist evidences by two different sampling preparation methods that the interaction mechanism between humic substances and hematite was mainly conform to the ligand exchange involving carboxylic functional groups of humic substances and the surfaces sites of hematite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in this field.
基金Project(2006AA06Z318) supported by the National High-Tech Research and Development Program of China
文摘The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.
基金supported by the National Key R&D Program of China (No.2018YFD0901004)the Central Public-Interest Scientific Institution Basal Research Fund,YSFRI,CAFS (No.20603022020013).
文摘Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus vannamei from two aquaculture patterns(earthen pond and greenhouse)using amino acid automatic analyzer,high-performance liquid chromatography(HPLC),gas chromatography(GC)-ion mobility spectrometry(IMS),and GC-mass spectrometry(GC-MS).The results revealed that dried shrimp from earthen pond had significantly higher free amino acids and 5’-nucleotides than those from greenhouse(P<0.05),and their corresponding equivalent umami concentrations(EUCs)were 23.45 g MSG(100 g)^(−1)and 14.86 g MSG(100 g)^(−1),respectively.For volatile compounds,GC-IMS analysis indicated significant differences in volatile compounds between dried shrimp from different aquaculture patterns.According to the quantitative analysis of GC-MS,11 volatile compounds were identified as aroma-active compounds(AACs),of which six AACs(1-octen-3-ol,3-methylbutanal,nonanal,trimethylamine,2,5-dimethylpyrazine,and 2,3,5-trimethylpyrazine)were found in all dried shrimp samples.Although dried shrimp from greenhouse possesses higher OAVs,OAVs of(E,E)-2,4-nonadienal(fishy smell),and 3,5-diethyl-2-methylpyrazine(burnt smell)reached 171.2 and 333 respectively,imparting negative effects on flavor.In general,dried shrimp from earthen pond had a better flavor profile than those from greenhouse.
基金Project(2009ZX07424-004) supported by the Water Special Program of China
文摘Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.
