A xylanase-producing bacterium, isolated from deep sea sediments, was identified as the cold-adapted marine species Acinetobacter Johnsonii. A cold-adapted marine species Acinetobacter Johnsonii could grow at 4 ℃. Th...A xylanase-producing bacterium, isolated from deep sea sediments, was identified as the cold-adapted marine species Acinetobacter Johnsonii. A cold-adapted marine species Acinetobacter Johnsonii could grow at 4 ℃. The optimum temperature and pH of xylanase from a cold-adapted marine species Acinetobacter Johnsonii were 55 ℃ and pH 6.0. Xylanase from a cold-adapted marine species Acinetobacter Johnsonii remained at 80% activity after incubation for 1 h at 65 ℃. The xylanase activity was 1.2-fold higher in 4% ethanol solution than in ethanol free solution. Gibbs free energy of denaturation, ΔG, was higher in 4% ethanol solution than in ethanol free solution. Thermostable ethanol tolerant xylanase was valuable for bioethanol production by simultaneous saccharification and fermentation process with xylan as a carbon source.展开更多
The potential of 324 bacteria isolated from different habitats in polar oceans to produce a variety of extracellular enzymatic activities at low temperature was investigated. By plate assay, lipase, protease, amylase,...The potential of 324 bacteria isolated from different habitats in polar oceans to produce a variety of extracellular enzymatic activities at low temperature was investigated. By plate assay, lipase, protease, amylase, gelatinase, agarase, chitinase or cellulase were detected. Lipases were generally present by bacteria living in polar oceans. Protease-producing bacteria held the second highest proportion in culturable isolates. Strains producing amylase kept a relative stable proportion of around 30% in different polar marine habitats. All 50 Arctic sea-ice bacteria producing proteases were cold-adapted strains, however, only 20% were psychrophilic. 98% of them could grow at 3% NaCl, and 56% could grow without NaCl. On the other hand, 98% of these sea-ice bacteria produced extracellular proteases with optimum temperature at or higher than 35℃, well above the upper temperature limit of cell growth. Extracellular enzymes including amylase, agarase, cellulase and lipase released by bacteria from seawater or sediment in polar oceans, most expressed maximum activities between 25 and 35℃. Among extracellular enzymes released by bacterial strain BSw20308, protease expressed maximum activity at 40℃, higher than 35℃ of polysaccharide hydrolases and 25℃ of lipase.展开更多
Strain of Pseudomonas Lip35 producing lipase was isolated in a refrigerator. Lipase production and characterization of this strain were investigated under different conditions. The Pseudomonas was cultivated in shakin...Strain of Pseudomonas Lip35 producing lipase was isolated in a refrigerator. Lipase production and characterization of this strain were investigated under different conditions. The Pseudomonas was cultivated in shaking flasks in a fermentation medium in various nutritional and physical environments. Lipase production has been influenced by the presence of yeast-extract, soybean powder, NaCI, and Tween-80. Maximum lipase productivity was obtained when the physical environment of the fermentation medium was optimal for 67 h. The production of lipase reached 58.9 U·mL^-1. The lipase of Pseudomonas Lip35 can be considered to be inducible, but the inducer had little influence on the production of lipase. The lipase was characterized and showed high lipolytic activity from pH 7.5-8.0. The optimum temperature was observed at 20℃ and the thermal inactivation of lipase was obvious at 60℃. The lipase activity was inhibited by K＋, stimulated by Ca^2＋, and thermostability decreased in the presence of Ca^2＋, therefore the lipase was Ca^2＋ -dependent cold-adapted enzyme.展开更多
Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession ...Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.展开更多
Gum Arabic (GA) from Acacia senegal var. kerensis has been approved as an emulsifier, stabilizer, thickener, and encapsulator in food processing industry. Chia mucilage, on the other hand, has been approved to be used...Gum Arabic (GA) from Acacia senegal var. kerensis has been approved as an emulsifier, stabilizer, thickener, and encapsulator in food processing industry. Chia mucilage, on the other hand, has been approved to be used as a fat and egg yolk mimic. However, both chia mucilage and gum Arabic are underutilized locally in Kenya;thus, marginal reports have been published despite their potential to alter functional properties in food products. In this study, the potential use of chia mucilage and gum Arabic was evaluated in the development of an eggless fat-reduced mayonnaise (FRM). The mayonnaise substitute was prepared by replacing eggs and partially substituting sunflower oil with chia mucilage at 15%, 30%, 45%, and 60% levels and gum Arabic at 3% while reducing the oil levels to 15%, 30%, 45%, and 60%. The effect of different concentrations of oil and chia mucilage on the physicochemical properties, for example, pH, emulsion stability, moisture content, protein, carbohydrate, fats, calories, ash, and titratable acidity using AOAC methods and sensory properties for both consumer acceptability and quantitative descriptive analysis of mayonnaise were evaluated and compared to the control with eggs and 75% sunflower oil. The results indicated that all fat-reduced mayonnaises had significantly lower energy to 493 kcal/100g and 20% fat content but higher water content of 0.74 than the control with 784 Kcal/100g calories, 77% fat and 0.39 moisture. These differences increased with increasing substitution levels of chia mucilage, as impacted on pH, carbohydrate, and protein. There was no significant difference between ash content for both fat-reduced mayonnaise and control. Sensory evaluation demonstrated that mayonnaises substituted with chia seeds mucilage and gum Arabic were accepted. All the parameters are positively correlated to overall acceptability, with flavor having the strongest correlation of r = 0.78. Loadings from principal component analysis (PCA) of 16 sensory attributes of mayonnaise showed that approximately over 66% of the variations in sensory attributes were explained by the first six principal components. This study shows good potential for chia mucilage and gum Arabic to be used as fat and egg mimetics and stabilizers, respectively, in mayonnaise with functional properties.展开更多
Botanical traits, genetic resources and cultivation of Salvia hispanica L. were reviewed in the article, which introduced the reasons why S. hispanica had late blooming period and low yield during the planting process...Botanical traits, genetic resources and cultivation of Salvia hispanica L. were reviewed in the article, which introduced the reasons why S. hispanica had late blooming period and low yield during the planting process in China, and envis- aged how to solve the late blooming period and low yield appeared during the planting process. Emphasis was laid on the introduction of the research progress of efficacy constituents and health care value of Chia seeds with the aim to take full advantage of S. hispanica.展开更多
We assessed different rootstocks and grafting techniques to clonally propagate mastic tree （Pistacia lentiscus var. chia）. Mastic tree is a dioecious tree but the quantity and quality of the resin secreted by female...We assessed different rootstocks and grafting techniques to clonally propagate mastic tree （Pistacia lentiscus var. chia）. Mastic tree is a dioecious tree but the quantity and quality of the resin secreted by female trees are very low; therefore, male trees that are clonally propagated are used to establish commercial plantations for mastic production. Conventional long branch cuttings for clonal production requires too much materials and has a very low rooting rate. Rooting with tissue culture and green cuttings has also failed outdoors. Grafting of mastic on other Pistacia species has not been tried so far; therefore, this study was aimed at developing grafting methods for the clonal propagation of mastic. P. atlantica and P. lentiscus rootstocks were grafted from 15 February to 15 October every 15 days using three grafting methods and a two-factor randomized block trial design. Early spring （15 February-15 March） proved to be the best time for grafting using either of the rootstocks. The highest grafting success was attained using the scions grafted on P. atlantica from 15 February to 15 March. The best bud-burst percentage was obtained using P. atlantica and P. lentiscus rootstocks.展开更多
Pear ring rot,caused by the pathogenic fungi Botryosphaeria dothidea,seriously affects pear production.While the infection-induced reactive oxygen species(ROS)burst of infected plants limits the proliferation of B.dot...Pear ring rot,caused by the pathogenic fungi Botryosphaeria dothidea,seriously affects pear production.While the infection-induced reactive oxygen species(ROS)burst of infected plants limits the proliferation of B.dothidea during the early infection stage,high ROS levels can also contribute to their growth during the later necrotrophic infection stage.Therefore,it is important to understand how plants balance ROS levels and resistance to pathogenic B.dothidea during the later stage.In this study,we identified PbrChiA,a glycosyl hydrolases 18(GH18)chitinase-encoding gene with high infection-induced expression,through a comparative transcriptome analysis.Artificial substitution,stable overexpression,and virus induced gene silencing(VIGS)experiments demonstrated that PbrChiA can positively regulate pear resistance as a secreted chitinase to break down B.dothidea mycelium in vitro and that overexpression of PbrChiA suppressed infection-induced ROS accumulation.Further analysis revealed that PbrChiA can bind to the ectodomain of PbrLYK1b2,and this interaction suppressed PbrLYK1b2-mediated chitin-induced ROS accumulation.Collectively,we propose that the combination of higher antifungal activity from abundant PbrChiA and lower ROS levels during later necrotrophic infection stage confer resistance of pear against B.dothidea.展开更多
Chia seeds played an important role in different ethnic group＇s diet at pre-Hispanic times. Later, it was domesticated due to high demand by the population and nowadays it＇s cultivated in several states of Mexico. H...Chia seeds played an important role in different ethnic group＇s diet at pre-Hispanic times. Later, it was domesticated due to high demand by the population and nowadays it＇s cultivated in several states of Mexico. However, seeds are not part of the Mexican average diet. The aim of this research was to asses Chia seed＇s macronutrients and promote consumption among population to decrease malnutrition. Chia seeds were collected at Puebla State （2015） and analyzed according to AOAC [1] methods. Data obtained （g/100 g dry basis） were： proteins 18.51%; lipids 31.33%; minerals 4.45%; fiber 24.45%; soluble carbohydrates 21.38%. Chia seeds absorb water about ten times its weight, is gluten free and contain a good amount of proteins, indispensable for human life In addition, Chia seeds have a balanced amount of polyunsaturated essential lipids, which are important for brain function, minerals, fiber and soluble carbohydrates. Chia seeds are available all year and are well accepted by all social groups, therefore it could be a good option to improve human health.展开更多
A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA anal...A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15~C and 30~C, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35~C and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride （PMSF） and hydrochloride 4-（2-aminoethyl）-benzenesulfonyl fluoride （AEBSF）, indicating that it was a serine protease. The presence of Cae＋ and Mnz＋ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid （AA） residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family.展开更多
基金Supported by the Science and Technology Research Project of Hubei Provincial Department of Education(B2017041)
文摘A xylanase-producing bacterium, isolated from deep sea sediments, was identified as the cold-adapted marine species Acinetobacter Johnsonii. A cold-adapted marine species Acinetobacter Johnsonii could grow at 4 ℃. The optimum temperature and pH of xylanase from a cold-adapted marine species Acinetobacter Johnsonii were 55 ℃ and pH 6.0. Xylanase from a cold-adapted marine species Acinetobacter Johnsonii remained at 80% activity after incubation for 1 h at 65 ℃. The xylanase activity was 1.2-fold higher in 4% ethanol solution than in ethanol free solution. Gibbs free energy of denaturation, ΔG, was higher in 4% ethanol solution than in ethanol free solution. Thermostable ethanol tolerant xylanase was valuable for bioethanol production by simultaneous saccharification and fermentation process with xylan as a carbon source.
基金supported by grants from the National Science Foundation of China(30200001,40376001)the National Science and Technology Ministry of China(2001DIA50040,2003DEB5J057)+1 种基金Oceanographic Science Fund of State Oceanic Administration(2004201)Polar Research Institute of China(JDQ200401).
文摘The potential of 324 bacteria isolated from different habitats in polar oceans to produce a variety of extracellular enzymatic activities at low temperature was investigated. By plate assay, lipase, protease, amylase, gelatinase, agarase, chitinase or cellulase were detected. Lipases were generally present by bacteria living in polar oceans. Protease-producing bacteria held the second highest proportion in culturable isolates. Strains producing amylase kept a relative stable proportion of around 30% in different polar marine habitats. All 50 Arctic sea-ice bacteria producing proteases were cold-adapted strains, however, only 20% were psychrophilic. 98% of them could grow at 3% NaCl, and 56% could grow without NaCl. On the other hand, 98% of these sea-ice bacteria produced extracellular proteases with optimum temperature at or higher than 35℃, well above the upper temperature limit of cell growth. Extracellular enzymes including amylase, agarase, cellulase and lipase released by bacteria from seawater or sediment in polar oceans, most expressed maximum activities between 25 and 35℃. Among extracellular enzymes released by bacterial strain BSw20308, protease expressed maximum activity at 40℃, higher than 35℃ of polysaccharide hydrolases and 25℃ of lipase.
基金supported by the Major Program of the Hebei Province Commission of Science and Technology during the 11 th Five-Year-Plan period,China(06220106D)
文摘Strain of Pseudomonas Lip35 producing lipase was isolated in a refrigerator. Lipase production and characterization of this strain were investigated under different conditions. The Pseudomonas was cultivated in shaking flasks in a fermentation medium in various nutritional and physical environments. Lipase production has been influenced by the presence of yeast-extract, soybean powder, NaCI, and Tween-80. Maximum lipase productivity was obtained when the physical environment of the fermentation medium was optimal for 67 h. The production of lipase reached 58.9 U·mL^-1. The lipase of Pseudomonas Lip35 can be considered to be inducible, but the inducer had little influence on the production of lipase. The lipase was characterized and showed high lipolytic activity from pH 7.5-8.0. The optimum temperature was observed at 20℃ and the thermal inactivation of lipase was obvious at 60℃. The lipase activity was inhibited by K＋, stimulated by Ca^2＋, and thermostability decreased in the presence of Ca^2＋, therefore the lipase was Ca^2＋ -dependent cold-adapted enzyme.
基金The work was supported by the Hi-Tech Research and Development Program of China under contract Nos 2006AA09Z414 and 2007AA091903；the China Ocean Mineral Resources R ＆ D Association under contract No. DYXM - 115 - 02 - 2 - 6；the National Natural Science Foundation of China under contract No. Z2004D02；the Natural Science Foundation of Shandong Province of China under contract No. Z2004D02；the Foundation for Young Excellent Scientists in Shandong Province of China under contract No. 2006BS02002；the Program for New Century Excellent Talents in University under contract No. NCET - 06 - 0578.
文摘Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.
文摘Gum Arabic (GA) from Acacia senegal var. kerensis has been approved as an emulsifier, stabilizer, thickener, and encapsulator in food processing industry. Chia mucilage, on the other hand, has been approved to be used as a fat and egg yolk mimic. However, both chia mucilage and gum Arabic are underutilized locally in Kenya;thus, marginal reports have been published despite their potential to alter functional properties in food products. In this study, the potential use of chia mucilage and gum Arabic was evaluated in the development of an eggless fat-reduced mayonnaise (FRM). The mayonnaise substitute was prepared by replacing eggs and partially substituting sunflower oil with chia mucilage at 15%, 30%, 45%, and 60% levels and gum Arabic at 3% while reducing the oil levels to 15%, 30%, 45%, and 60%. The effect of different concentrations of oil and chia mucilage on the physicochemical properties, for example, pH, emulsion stability, moisture content, protein, carbohydrate, fats, calories, ash, and titratable acidity using AOAC methods and sensory properties for both consumer acceptability and quantitative descriptive analysis of mayonnaise were evaluated and compared to the control with eggs and 75% sunflower oil. The results indicated that all fat-reduced mayonnaises had significantly lower energy to 493 kcal/100g and 20% fat content but higher water content of 0.74 than the control with 784 Kcal/100g calories, 77% fat and 0.39 moisture. These differences increased with increasing substitution levels of chia mucilage, as impacted on pH, carbohydrate, and protein. There was no significant difference between ash content for both fat-reduced mayonnaise and control. Sensory evaluation demonstrated that mayonnaises substituted with chia seeds mucilage and gum Arabic were accepted. All the parameters are positively correlated to overall acceptability, with flavor having the strongest correlation of r = 0.78. Loadings from principal component analysis (PCA) of 16 sensory attributes of mayonnaise showed that approximately over 66% of the variations in sensory attributes were explained by the first six principal components. This study shows good potential for chia mucilage and gum Arabic to be used as fat and egg mimetics and stabilizers, respectively, in mayonnaise with functional properties.
文摘Botanical traits, genetic resources and cultivation of Salvia hispanica L. were reviewed in the article, which introduced the reasons why S. hispanica had late blooming period and low yield during the planting process in China, and envis- aged how to solve the late blooming period and low yield appeared during the planting process. Emphasis was laid on the introduction of the research progress of efficacy constituents and health care value of Chia seeds with the aim to take full advantage of S. hispanica.
基金financially supported by the Aegean Forestry Research Institute(No.15.2110/2008-2010)zmir Regional Directorate of Forestry
文摘We assessed different rootstocks and grafting techniques to clonally propagate mastic tree （Pistacia lentiscus var. chia）. Mastic tree is a dioecious tree but the quantity and quality of the resin secreted by female trees are very low; therefore, male trees that are clonally propagated are used to establish commercial plantations for mastic production. Conventional long branch cuttings for clonal production requires too much materials and has a very low rooting rate. Rooting with tissue culture and green cuttings has also failed outdoors. Grafting of mastic on other Pistacia species has not been tried so far; therefore, this study was aimed at developing grafting methods for the clonal propagation of mastic. P. atlantica and P. lentiscus rootstocks were grafted from 15 February to 15 October every 15 days using three grafting methods and a two-factor randomized block trial design. Early spring （15 February-15 March） proved to be the best time for grafting using either of the rootstocks. The highest grafting success was attained using the scions grafted on P. atlantica from 15 February to 15 March. The best bud-burst percentage was obtained using P. atlantica and P. lentiscus rootstocks.
基金This work has been supported by the National Key Research and Development Program of China(2018YFD1000300)the National Science Foundation of China(31872070,32072538),Fundamental Research Funds for the Central Universities(JCQY201901)+1 种基金the Earmarked Fund for China Agriculture Research System(CARS-28)the Jiangsu Agriculture Science and Technology Innovation Fund(SCX(22)3215).Bioinformatic analysis was supported by the Bioinformatics Center of Nanjing Agricultural University.We also thank Dr Jianming Zeng(University of Macao),and all the members of his bioinformatics team,biotrainee,for generously sharing their experience and codes.
文摘Pear ring rot,caused by the pathogenic fungi Botryosphaeria dothidea,seriously affects pear production.While the infection-induced reactive oxygen species(ROS)burst of infected plants limits the proliferation of B.dothidea during the early infection stage,high ROS levels can also contribute to their growth during the later necrotrophic infection stage.Therefore,it is important to understand how plants balance ROS levels and resistance to pathogenic B.dothidea during the later stage.In this study,we identified PbrChiA,a glycosyl hydrolases 18(GH18)chitinase-encoding gene with high infection-induced expression,through a comparative transcriptome analysis.Artificial substitution,stable overexpression,and virus induced gene silencing(VIGS)experiments demonstrated that PbrChiA can positively regulate pear resistance as a secreted chitinase to break down B.dothidea mycelium in vitro and that overexpression of PbrChiA suppressed infection-induced ROS accumulation.Further analysis revealed that PbrChiA can bind to the ectodomain of PbrLYK1b2,and this interaction suppressed PbrLYK1b2-mediated chitin-induced ROS accumulation.Collectively,we propose that the combination of higher antifungal activity from abundant PbrChiA and lower ROS levels during later necrotrophic infection stage confer resistance of pear against B.dothidea.
文摘Chia seeds played an important role in different ethnic group＇s diet at pre-Hispanic times. Later, it was domesticated due to high demand by the population and nowadays it＇s cultivated in several states of Mexico. However, seeds are not part of the Mexican average diet. The aim of this research was to asses Chia seed＇s macronutrients and promote consumption among population to decrease malnutrition. Chia seeds were collected at Puebla State （2015） and analyzed according to AOAC [1] methods. Data obtained （g/100 g dry basis） were： proteins 18.51%; lipids 31.33%; minerals 4.45%; fiber 24.45%; soluble carbohydrates 21.38%. Chia seeds absorb water about ten times its weight, is gluten free and contain a good amount of proteins, indispensable for human life In addition, Chia seeds have a balanced amount of polyunsaturated essential lipids, which are important for brain function, minerals, fiber and soluble carbohydrates. Chia seeds are available all year and are well accepted by all social groups, therefore it could be a good option to improve human health.
基金supported by the National High Technology Research and Development Program of China (Grant no. 2007AA091407)the Project of China Ocean Mineral Resources Research and Development Association (COMRA, Grant no. DYXM-115-02-2-04)
文摘A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15~C and 30~C, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35~C and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride （PMSF） and hydrochloride 4-（2-aminoethyl）-benzenesulfonyl fluoride （AEBSF）, indicating that it was a serine protease. The presence of Cae＋ and Mnz＋ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid （AA） residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family.
