Objective To establish a method for simultaneous determination of trace levels of microcystins,cylindrospermopsin,anatoxin,and nodularin in lake water based on liquid chromatography-tandem mass spectrometry(LC-MS/MS).Methods After being adjusted to alkaline conditions and mixed with six internal standards,the water samples were enriched using dual HLB and ENVI-Carb cartridges.The eluates were then evaporated under nitrogen,reconstituted,and subjected to instrumental analysis.Both water and acetonitrile containing 0.1%formic acid were used as mobile phases.An ACQUITY UPLC? BEH C18 column(150 mm×2.1 mm,1.7 μm)was selected to separate the target cyanotoxins.Multiple reaction monitoring was applied for data acquisition,and quantification was accomplished using internal standard methods.Results Within certain concentration ranges,all 14 cyanotoxins examined in the study showed good linearity,with all correlation coefficients greater than 0.998.When the water volume was 100 mL,the limits of detection and quantification for the 14 cyanotoxins were 0.1-0.9 ng/L and 0.3-2.9 ng/L,respectively,and spiked recoveries and relative standard deviations were 81.7%-132.9%and 1.2%-14.9%,respectively.In the 10 lake water samples analyzed,cylindrospermopsin,anatoxin-α,and multiple microcystins were detected.Conclusion The method developed in the study has high-throughput capacity,as well as high sensitivity,accuracy,and reliability.The method can be applied in the simultaneous detection of microcystins,cylindrospermopsin,anatoxin,and nodularin in lake water.

AIM:To investigate the effects of adipose-derived stem cells(ADSCs)with overexpression or si-lencing of long noncoding RNA(lncRNA)SNHG8 on the viability,migration,angiogenesis,and the expression of vasoac-tive factors in human umbilical vein endothelial cells(HUVECs).METHODS:Identification of ADSCs derived from morbidly obese patients(O-ADSCs)was conducted using flow cytometry and induction of lipogenesis and osteogenesis.The expression of lncRNA SNHG8 in healthy human ADSCs(H-ADSCs)and O-ADSCs was detected by RT-qPCR.Tran-swell method was used to establish the indirect co-culture system of ADSCs and HUVECs for 48 h,and the cells were di-vided into O-ADSCs+HUVECs group,H-ADSCs+HUVECs group,and HUVECs alone group.The mRNA and protein ex-pression levels of angiotensin Ⅱ(Ang Ⅱ),endothelin-1(ET-1)and endothelial nitric oxide synthase(eNOS)in HUVECs were detected by RT-qPCR and Western blot.The lncRNA SNHG8 overexpression and silencing lentiviruses were con-structed and used to infect O-ADSCs.The indirect co-cultured ADSCs and HUVECs were divided into O-ADSCs-OE-SNHG8+ HUVECs group,O-ADSCs-OE-NC+HUVECs group,O-ADSCs-sh-SNHG8+HUVECs group,and O-ADSCs-sh-NC+HUVECs group.After co-culture for 48 h,the viability,migration and tubule formation of HUVECs were detected by CCK-8,scratch and angiogenesis assays,respectively.The mRNA and protein expression levels of Ang Ⅱ,ET-1 and eNOS in HU-VECs were detected by RT-qPCR and Western blot,respectively.The nitrate reductase method was used to detect the con-tent of NO in HUVECs.RESULTS:(1)The cultured cells were identified as ADSCs.(2)Compared with H-ADSCs,ln-cRNA SNHG8 expression was significantly up-regulated in O-ADSCs(P<0.01).(3)Compared with H-ADSCs+HUVECs group and HUVECs group,the mRNA and protein expression levels of Ang Ⅱ and ET-1 in HUVECs in O-ADSCs+HU-VECs group were up-regulated(P<0.01).(4)Overexpression of lncRNA SNHG8 in O-ADSCs enhanced the viability,mi-gration and tube formation ability of HUVECs,up-regulated the mRNA and protein expression levels of Ang Ⅱ and ET-1,down-regulated the mRNA and protein expression levels of eNOS,and decreased the content of NO in HUVECs(P<0.05).However,silencing of lncRNA SNHG8 in O-ADSCs exerted opposite results(P<0.05).CONCLUSION:(1)The O-ADSCs can promote endothelial cell viability,migration and tubule formation through paracrine effects.(2)The O-ADSCs with overexpression of lncRNA SNHG8 promote the imbalance of diastolic and contractile factors secreted by endo-thelial cells,and induce the dysfunction of vascular endothelial cells.