Objective To clone and express a new PL25 family ulvan lyase,TsUly25A,and to characterise its properties and explore its application for the preparation of ulvan oligosaccharides.Methods The gene encoding ulvan lyase ...Objective To clone and express a new PL25 family ulvan lyase,TsUly25A,and to characterise its properties and explore its application for the preparation of ulvan oligosaccharides.Methods The gene encoding ulvan lyase of the PL25 family,tsuly25A,was cloned from Thalassomonas sp.LD5 and then expressed in Escherichia coli BL21(DE3).The recombinant enzyme TsUly25A was subsequently purified and its enzymatic properties were investigated.Results Its enzyme activity was highest at 50℃and pH 8.0,with a specific activity of 0.45 U/mg.NaCl exerted marginal effects on the activity and thermal stability of TsUly25A.TsUly25A could still degrade ulvan polysaccharides in pure water and retained about 60%of its activity.Conclusions Ulvan lyase TsUly25A could degrade ulvan polysaccharides in pure water,laying the foundation for the industrial application of ulvan lyase in the production of ulvan oligosaccharides.展开更多
Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic ...Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic acid and sulfuric acid and ash contents were 67.3%, 23.8%, 19.7% and 22.6%, respectively. L-Rhamnose, D-xylose and D-glucose residues were identified by liquid chromatography, and their molar ratio was 4.0:0.1:0.3. D-Glucuronic and L-idulonic acid residues were also identified in molar ratio of 1.0:0.2. The NMR (13C and 1H) and methylation analysis revealed terminal β-D-glucruonic acid, terminal α-L-idulonic acid, 1,3-linked α-L-rhamnose, 1,4-linked α-L-rhamnose, 1,2,4-linked α-L-rhamnose, 1,3,4-linked α-L-rhamnose, 1,2,3,4-linked α-L-rhamnose and 1,3,4-linked β-D-xylose. The sulfate groups were attached at the C-2 and C-3 positions of the 1,4-linked α-L-rhamnose as well as C-3 of the 1,4-linked β-D-xylose residues. The chemical structure of the ulvan from Ulva pertusa was determined.展开更多
Objective To estimate the antiviral activities of ulvan derived from Ulva pertusa,and initiate a preliminary exploration into its mechanism for the potential utilization of ulvans in the future.Methods Employing metho...Objective To estimate the antiviral activities of ulvan derived from Ulva pertusa,and initiate a preliminary exploration into its mechanism for the potential utilization of ulvans in the future.Methods Employing methodologies rooted in molecular biology and virology,such as viral infection and FACS,the effect of ulvan on virus infection and the innate immune responses in cells were evaluated.Results Ulvan significantly restricted vesicular stomatitis virus(VSV)infection.Preliminary exploration on its mechanism indicated that ulvan activated the innate immune,and induced type I interferons(IFN-Ⅰ)expression to restrict viral infection.展开更多
Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstu...Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.展开更多
文摘Objective To clone and express a new PL25 family ulvan lyase,TsUly25A,and to characterise its properties and explore its application for the preparation of ulvan oligosaccharides.Methods The gene encoding ulvan lyase of the PL25 family,tsuly25A,was cloned from Thalassomonas sp.LD5 and then expressed in Escherichia coli BL21(DE3).The recombinant enzyme TsUly25A was subsequently purified and its enzymatic properties were investigated.Results Its enzyme activity was highest at 50℃and pH 8.0,with a specific activity of 0.45 U/mg.NaCl exerted marginal effects on the activity and thermal stability of TsUly25A.TsUly25A could still degrade ulvan polysaccharides in pure water and retained about 60%of its activity.Conclusions Ulvan lyase TsUly25A could degrade ulvan polysaccharides in pure water,laying the foundation for the industrial application of ulvan lyase in the production of ulvan oligosaccharides.
文摘Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic acid and sulfuric acid and ash contents were 67.3%, 23.8%, 19.7% and 22.6%, respectively. L-Rhamnose, D-xylose and D-glucose residues were identified by liquid chromatography, and their molar ratio was 4.0:0.1:0.3. D-Glucuronic and L-idulonic acid residues were also identified in molar ratio of 1.0:0.2. The NMR (13C and 1H) and methylation analysis revealed terminal β-D-glucruonic acid, terminal α-L-idulonic acid, 1,3-linked α-L-rhamnose, 1,4-linked α-L-rhamnose, 1,2,4-linked α-L-rhamnose, 1,3,4-linked α-L-rhamnose, 1,2,3,4-linked α-L-rhamnose and 1,3,4-linked β-D-xylose. The sulfate groups were attached at the C-2 and C-3 positions of the 1,4-linked α-L-rhamnose as well as C-3 of the 1,4-linked β-D-xylose residues. The chemical structure of the ulvan from Ulva pertusa was determined.
文摘Objective To estimate the antiviral activities of ulvan derived from Ulva pertusa,and initiate a preliminary exploration into its mechanism for the potential utilization of ulvans in the future.Methods Employing methodologies rooted in molecular biology and virology,such as viral infection and FACS,the effect of ulvan on virus infection and the innate immune responses in cells were evaluated.Results Ulvan significantly restricted vesicular stomatitis virus(VSV)infection.Preliminary exploration on its mechanism indicated that ulvan activated the innate immune,and induced type I interferons(IFN-Ⅰ)expression to restrict viral infection.
基金Fundaçao para a Ciencia e Tecnologia(FCT,Lisbon,Portugal)through grant PTDC/CAL-ZOO/30238/2017 associated post-doc contract to MMC,CIISA(Project UIDB/00276/2020)a PhD fellowship to DFC(SFRH/BD/126198/2016).
文摘Green macroalgae,e.g.,Ulva lactuca,are valuable bioactive sources of nutrients;but algae recalcitrant cell walls,composed of a complex cross-linked matrix of polysaccharides,can compromise their utilization as feedstuffs for monogastric animals.This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes(CAZymes)and sulfatases to degrade U.lactuca cell walls and release nutritive compounds.A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U.lactuca cell wall polysaccharides.The enzymes were incubated with the macroalga,either alone or in combination,to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls.The individual action of a polysaccharide lyase family 25(PL25),an ulvan lyase,was shown to be the most efficient in cell wall disruption.The ulvan lyase treatment,in triplicate measures,promoted the release of 4.54 g/L(P<0.001)reducing sugars,a mono-and oligosaccharides release of 11.4 and 11.2 mmol/100 g of dried alga(P<0.01),respectively,and a decrease of 41.7%(P<0.001)in cell wall fluorescence,in comparison to control.The ability of ulvan lyase treatment to promote the release of nutritional compounds from alga biomass was also evaluated.A release of some monounsaturated fatty acids was observed,particularly the health beneficial 18:1c9(P<0.001).However,no significant release of total fatty acids(P>0.05),proteins(P?0.861)or pigments(P>0.05)was found.These results highlight the capacity of a single recombinant ulvan lyase(PL25 family)to incompletely disrupt U.lactuca cell walls.This enzyme could enhance the bioaccessibility of U.lactuca bioactive products with promising utilization in the feed industry.
