Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various...Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.展开更多
Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental a...Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator.The results showed that the biomass（Chl a）and photosynthesis of algae were inhibited under P-limitation conditions,while the phosphatase activity and P assimilation rate were promoted.The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability.Cyanobacteria were more competitive than other algae in biofilms,particularly when cultured under low P levels.A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01,0.1 and 0.6 mg/L.However,the total N content,dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability.This may be attributed to the low respiration rate,high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low.The bacterial community structure differed over time,while there was little difference between the four treatments,which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability.Altogether,these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water.展开更多
Organic agriculture is gaining momentum in the Philippines as consumers become more health- and environment-conscious. This study investigated soil fertility based on soil chemistry and biological properties of organi...Organic agriculture is gaining momentum in the Philippines as consumers become more health- and environment-conscious. This study investigated soil fertility based on soil chemistry and biological properties of organic vegetable farms in Sariaya, Quezon Province and Los Baños, Laguna Province, with the aim of developing organic agriculture in the Philippines. We utilized the SOFIX (Soil Fertility Index) technology, which is designed to evaluate soil fertility by focusing on the activity and diversity of microbial communities in the soil. This technology provides a scientific assessment of soil health, aiming to contribute to sustainable agriculture and environmental conservation. Soil fertility parameters from four different farms cultivating outdoor organic vegetables were below the recommended values for organic production. Essential macronutrients like nitrogen, phosphorus, and potassium and total carbon content, which is indicative of soil organic matter, were insufficient. Bacterial biomass for soil organic matter decomposition, and nitrogen and phosphorus circulation was inadequate. These results indicated that organic plots lack the fertility needed for optimal organic crop growth. The poor fertility of these organic plots could be attributed to their recent shift from conventional cultivation, which used synthetic pesticides and chemical fertilizers, to organic cultivation approximately seven years ago. This shift may harm soil microorganisms, leading to decreased fertility, nutrient availability and hindering the ability to sustain organic production. Overall, the findings of this case study emphasize the significant soil fertility challenges on organic vegetable farms. Therefore, farmers and agricultural practitioners must adopt appropriate soil management practices to improve soil fertility, microbial populations, nutrient availability, and overall soil health for successful organic production.展开更多
In this article, a novel oligomerization behavior of unprotected monosaccharides was discovered in a one-pot reaction induced by phosphorus reagent at room temperature. The inherent characteristics of the oligomerizat...In this article, a novel oligomerization behavior of unprotected monosaccharides was discovered in a one-pot reaction induced by phosphorus reagent at room temperature. The inherent characteristics of the oligomerization reaction were dissected in detail by mass spectrometry based method combined with NMR technology. It was found that the main glycosidic bonding pattern is (1→6) linkage with 66% regioselectivity for each step. The ratio of α-(1→6) and β-(1→6) glycosidic bonds formed is around 1:1. The reactivity of 1-OH group from aldoses and the driving force from penta-coordinated phosphorus intermediates are the two critical factors for the oligomerization, according to the monitoring experiments by ESI-MS and NMR. Besides, the oligomerization reaction has good compatibility for various aldoses and could expand to O-glycosylated modification of peptides in vitro. The above results will provide a novel enlightenment to develop more convenient and higher-efficient methods for the synthesis of oligosaccharide library.展开更多
基金supported by the Project of Ecological and Environmental Protection Integration Research Institute in Yangtze River Delta(No.ZX2023SZY118)the Special Basic Research Service for the Central Level Public Welfare Research Institute(No.GYZX230409)+1 种基金the National Natural Science Foundation of China(No.42407557)the Belt and Road Special Foundation of the National Key Laboratory of Water Disaster Prevention,China(No.2023491611)。
文摘Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No2012ZX07103003-02)
文摘Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator.The results showed that the biomass（Chl a）and photosynthesis of algae were inhibited under P-limitation conditions,while the phosphatase activity and P assimilation rate were promoted.The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability.Cyanobacteria were more competitive than other algae in biofilms,particularly when cultured under low P levels.A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01,0.1 and 0.6 mg/L.However,the total N content,dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability.This may be attributed to the low respiration rate,high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low.The bacterial community structure differed over time,while there was little difference between the four treatments,which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability.Altogether,these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water.
文摘Organic agriculture is gaining momentum in the Philippines as consumers become more health- and environment-conscious. This study investigated soil fertility based on soil chemistry and biological properties of organic vegetable farms in Sariaya, Quezon Province and Los Baños, Laguna Province, with the aim of developing organic agriculture in the Philippines. We utilized the SOFIX (Soil Fertility Index) technology, which is designed to evaluate soil fertility by focusing on the activity and diversity of microbial communities in the soil. This technology provides a scientific assessment of soil health, aiming to contribute to sustainable agriculture and environmental conservation. Soil fertility parameters from four different farms cultivating outdoor organic vegetables were below the recommended values for organic production. Essential macronutrients like nitrogen, phosphorus, and potassium and total carbon content, which is indicative of soil organic matter, were insufficient. Bacterial biomass for soil organic matter decomposition, and nitrogen and phosphorus circulation was inadequate. These results indicated that organic plots lack the fertility needed for optimal organic crop growth. The poor fertility of these organic plots could be attributed to their recent shift from conventional cultivation, which used synthetic pesticides and chemical fertilizers, to organic cultivation approximately seven years ago. This shift may harm soil microorganisms, leading to decreased fertility, nutrient availability and hindering the ability to sustain organic production. Overall, the findings of this case study emphasize the significant soil fertility challenges on organic vegetable farms. Therefore, farmers and agricultural practitioners must adopt appropriate soil management practices to improve soil fertility, microbial populations, nutrient availability, and overall soil health for successful organic production.
基金supported by the National Natural Science Foundation of China (21232005)the Natural Science Foundation of Fujian Province of China (2017J01024)the Fundamental Research Funds for the Central Universities (20720150049)
文摘In this article, a novel oligomerization behavior of unprotected monosaccharides was discovered in a one-pot reaction induced by phosphorus reagent at room temperature. The inherent characteristics of the oligomerization reaction were dissected in detail by mass spectrometry based method combined with NMR technology. It was found that the main glycosidic bonding pattern is (1→6) linkage with 66% regioselectivity for each step. The ratio of α-(1→6) and β-(1→6) glycosidic bonds formed is around 1:1. The reactivity of 1-OH group from aldoses and the driving force from penta-coordinated phosphorus intermediates are the two critical factors for the oligomerization, according to the monitoring experiments by ESI-MS and NMR. Besides, the oligomerization reaction has good compatibility for various aldoses and could expand to O-glycosylated modification of peptides in vitro. The above results will provide a novel enlightenment to develop more convenient and higher-efficient methods for the synthesis of oligosaccharide library.
