AIM： To evaluate the antiviral effect of the effective ingredient of Styela plicata in a murine model of hepatitis B virus carrier. METHODS： HBV-transgenic mice were divided into 3 groups （control group, lamivudine...AIM： To evaluate the antiviral effect of the effective ingredient of Styela plicata in a murine model of hepatitis B virus carrier. METHODS： HBV-transgenic mice were divided into 3 groups （control group, lamivudine treatment group and the effective ingredient of Styela plicata treatment group） and assigned to receive normal diet, lamivudine or the effective ingredient of Styela plicata for consecutive weeks. Serum hepatitis B surface antigen was detected by enzyme-linked immunosorbent assay （ELISA） method. Serum HBV DNA was detected by real-time polymerase chain reaction （RT-PCR）. Serum T helper （h） 1 cytokine interleukin （IL）-2 and Th2 cytokine IL-6 were detected by the quantitative sandwich enzyme immunoassay technique. Another group of HBV-transgenic mice was assigned to receive the effective ingredient of Styela plicata for consecutive weeks. The histology of liver tissue was evaluated before and after treatment. RESULTS： Twelve weeks after starting the therapy, serum hepatitis B surface antigen was significantly lowered in Styela plicata -treated mice and lamivudine-treated mice compared with the mice receiving normal diet （F12wk = 88.81, P12wk = 0.000 〈 0.01）. Serum HBV DNA was significantly lowered in Styela plicata -treated mice and lamivudine-treated mice compared with the mice receiving normal diet （F12wk = 20.71, P12wk = 0.000 〈 0.01）. However, like lamivudine, the effective ingredient of Styela plicata could not inhibit the replication of HBV completely. A rebound phenomenon of hepatitis B surface antigen and HBV DNA in sera could be found 4 wk after withdrawal of medication. Eight weeks after starting the therapy, serum levels before and after Styela plicata treatment of IL-2 were 2.41 ± 0.38 and 10.56 ± 0.78 ng/L, respectively （t8wk = -16.51, P8wk = 0.000 〈 0.01）. Compared with the serum levels of IL-2 in the normal diet-treated mice （2.48 ± 0.17 ng/L; t8wk = 13.23, P8wk = 0.000 〈 0.01）. Serum levels before and after Styela plicata treatment of IL-6 were 63.62 ± 6.31 and 54.52 ± 6.22 ng/L, respectively, compared with the serum levels of IL-6 in the normal diet-treated mice （60.84 ± 4.21 ng/L）. Histological analysis of liver from Styela plicata-treated HBV-transgenic mice also showed catabatic status in inflammation and hepatitis B surface antigen. CONCLUSION： Styela plicata may be an effective anviral medicine in treating chronic hepatitis B.展开更多
The thickness dependence of mechanical properties of nacre in Cristaria plicata shell was studied under three-point bending tests.The results show that the mechanical behavior of nacre exhibits a strong thickness depe...The thickness dependence of mechanical properties of nacre in Cristaria plicata shell was studied under three-point bending tests.The results show that the mechanical behavior of nacre exhibits a strong thickness dependence.The bending strength firstly increases with the increase of specimen thickness and then becomes roughly constant as the thickness reaches a certain value of∼2.5mm.However,the mean value of work per unit volume increases constantly with increasing specimen thickness;meanwhile,the cracking mode changes from penetration into the platelets to deflection along the interfaces.The theoretical analyses indicate that the thickness-dependent mechanical properties of nacre are mainly caused by the variation in the number of inter-lamellar interfaces.The more the number of inter-lamellar interfaces is,the higher the strength and work of fracture of nacre under bending tests will be.However,as the number of inter-lamellar interfaces reaches a certain value(e.g.,in the present specimen with 2.5mm thickness),the strength tends to remain constant,while the work of fracture still increases.Therefore,the present research findings are expected to provide a valuable guidance for the interfacial design of nacre-like materials with high strength and toughness.展开更多
Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in D...Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.展开更多
Agar,agarose,and agaropectin were extracted from the red alga Ahnfeltia plicata,and their properties and structures were characterized.Agar was extracted by a comparatively low alkaline consumption of 1.2%.It exhibite...Agar,agarose,and agaropectin were extracted from the red alga Ahnfeltia plicata,and their properties and structures were characterized.Agar was extracted by a comparatively low alkaline consumption of 1.2%.It exhibited a gel strength of 1 152.50±74.25 g/cm^2 and a sulfate content of 0.55%±0.08%.The yield of agar from A.plicata was 24.53%,which is higher than those of other agarophytes commonly used in China.Three kinds of the method were compared for the purification of agarose,and the physicochemical properties of agarose that was prepared under the optimal condition were identical to those of commercially available agarose.Furthermore,agaropectin was purified from A.plicata and characterized by GC,HPLC,UV-spectrum,and FI-IR to understand its composition and structure.It was the first time to comprehensively study the agar and its fractions from the red alga of A.plicata.This research provided an eco-friendly agar extraction method from A.plicata and revealed its potential application for the production of agar,agarose,and agaropectin.展开更多
Two new iridoid glycosides,plicatoside A and plicatoside B,were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaeno...Two new iridoid glycosides,plicatoside A and plicatoside B,were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaenoside by means of chemical evidence and spectral data.展开更多
Objective:To evaluate the antiviral activity of the alcohol extract of Styela plicata on DHBV (duck hepatitis B virus) in vivo. Methods: Guangzhou-Sheldrake ducklings congenitally infected with DHBV were assigned to r...Objective:To evaluate the antiviral activity of the alcohol extract of Styela plicata on DHBV (duck hepatitis B virus) in vivo. Methods: Guangzhou-Sheldrake ducklings congenitally infected with DHBV were assigned to receive the alcohol extract of Styela plicata or lamivudine for 30 consecutive days. The DHBV DNA of sera was detected by RT-PCR. and the histological analysis of duckling liver was evaluated. Results:Thirty days after therapy,histological analysis of duckling liver showed that the ducklings receiving the alcohol extract of Styela plicata or lamivudine exhibited catabatic status in the degree of liver cell degeneration and inflammation compared with the ducklings receiving normal diet. DHBV DNA of sera from alcohol extract of Styela plicata-treated ducklings and lamivudine-treated ducklings all produced significantly lower levels compared with ducklings receiving normal diet (P<0. 01 ). Although these treatment groups all exhibited a rebound phenomenon 10 d after withdrawal of medication, they still exhibited a significant lower level of serum DHBV DNA compared with the control group responded to normal diet (P<0. 05, P<0. 01). Conclusion:Styela plicata may be an effective antiviral medicine in treating chronic hepatitis B. The data of this experiment will be valuable in studying the therapeutic role and the potential therapeutic mechanism of Styela plicata.展开更多
[Objectives] To study in vitro antioxidant activity of extracts from Eleutherine plicata Herb by different extraction methods.[Methods]1,1-diphenyl-2-picrylhydrazyl( DPPH) free radical scavenging method,2,2'-Azino...[Objectives] To study in vitro antioxidant activity of extracts from Eleutherine plicata Herb by different extraction methods.[Methods]1,1-diphenyl-2-picrylhydrazyl( DPPH) free radical scavenging method,2,2'-Azinobis( 3-ehtylbenzothiazolin-6-sulfnic acid) diammonium salt( ABTS) free radical scavenging method,and iron ion reduction ability determination method were applied to measure the extracts of Eleutherine plicata Herb by ethanol extraction,water extraction,and ethanol extraction after water extraction,and comparison was made with positive control Vc( vitamin C). [Results]The ethanol extract,water extract,and ethanol extract after water extraction of Eleutherine plicata Herb had a high DPPH free radical,ABTS free radical scavenging activity,and reducing activity. [Conclusions]E. plicata Herb is a natural antioxidant with high potential.展开更多
IT has been demonstrated that two reproductive hormones,gonadotropin-releasing hormone(GnRH)and gonadotropin(GTH),exist in the nervous system and Hatschek’s pit oflancelet,a species of Cephalochordata,and that these ...IT has been demonstrated that two reproductive hormones,gonadotropin-releasing hormone(GnRH)and gonadotropin(GTH),exist in the nervous system and Hatschek’s pit oflancelet,a species of Cephalochordata,and that these hormones are involved in the regulationof gonadal development and reproductive activity of lancelet.However,no report could展开更多
Spathoglottis plicata Blume. is a horticulturally important vulnerable ground orchid with beautiful flowers blooming round the year. Highfrequency protocorm-like body(PLB) formation was established via callus culture ...Spathoglottis plicata Blume. is a horticulturally important vulnerable ground orchid with beautiful flowers blooming round the year. Highfrequency protocorm-like body(PLB) formation was established via callus culture from vegetative tissues of in vitro germinated seedlings of S.plicata. Media containing MS salts and Gamborg's B5 vitamins supplemented with 1.0 mg·L^(-1) 2,4-dichlorophenoxyacetic acid(2,4-D), 3.0 mg·L^(-1) α-naphthaleneacetic acid(NAA), 1.0 mg·L^(-1) kinetin(KIN), and 10%(v/v) ‘Aloe vera gel'(Av G) were effective in fragile calli induction. A maximum of(22.3 ± 0.52) PLBs were induced from about 250 mg callus within 45–55 days in the presence of 2.0 mg·L^(-1) NAA and 3.0 mg·L^(-1) 6-benzylaminopurine(BAP). Briefly, 3.0% sodium alginate was found to be most suitable for the formation of an appropriate shape and good germination rates(86.7%)of artificial seeds. Out of three different temperatures(4, 15, and 24 °C), the best result was achieved at 4 °C with 66.7% germinability even after90 days of storage. Plantlets were acclimatized with 86.6% survival rate and 76.3% of these plants produced flowers within 12–15 months of field transfer. Chromosomal studies revealed cytological stability of all regenerants containing 2 n = 40 chromosomes as in the parental plants.The present protocol can be applied reliably for the purposes of large-scale commercial propagation and short-term conservation of this orchid.展开更多
Partial sequences of the mitochondrial 16S rRNA gene were determined for two Sesarma species （S. haematocheir and S. pficata）, and the length of sequence of S. haematocheir and S. plicata was the same. Of the 533 nu...Partial sequences of the mitochondrial 16S rRNA gene were determined for two Sesarma species （S. haematocheir and S. pficata）, and the length of sequence of S. haematocheir and S. plicata was the same. Of the 533 nucleotides obtained, the A, T, G and C contents were similar, which were 198 bp （37.1%）, 206 bp （38.6%）, 84 bp （15.8%）, 45 bp （8.4%） and 200 bp （37.5%）, 205 bp （38.5%）, 81 bp （15.2%）, 47 bp （8.8%） respectively. There were 49 different sites between the two species, including 21 transition sites, 22 transversion sites and 6 deletion/insertion sites. Furthermore, 361 bp homologous fragment was analyzed to discuss the phylogenetic relationship of 20 Sesarma species. The results showed that AT content （78.6% - 82.9%） was higher than GC content and there were 91 vadable positions of 16S rRNA sequences among the 20 species. Among 3 Sesarma species in China, S. dehaani and S. haematocheir were closely related （d=0.0151）; and there were greater genetic distances between S. pficata and S. dehaani I S. haematocheir （d=0.0924/0.0923）. The average genetic distances of S. plicata , S. dehaani and S. haematocheir with the North American crabs of genus Sesarma were respectively 0.103 2 ± 0.008 9, 0.0783±0.0105 and 0.072 0± 0.011, which indicated that there were greater genetic differences between China and North American Sesarma crabs and they were monophyletic each other.展开更多
基金Supported by the Social Development Program of Department of Science and Technology of Guangdong Province, No.2004B30101009
文摘AIM： To evaluate the antiviral effect of the effective ingredient of Styela plicata in a murine model of hepatitis B virus carrier. METHODS： HBV-transgenic mice were divided into 3 groups （control group, lamivudine treatment group and the effective ingredient of Styela plicata treatment group） and assigned to receive normal diet, lamivudine or the effective ingredient of Styela plicata for consecutive weeks. Serum hepatitis B surface antigen was detected by enzyme-linked immunosorbent assay （ELISA） method. Serum HBV DNA was detected by real-time polymerase chain reaction （RT-PCR）. Serum T helper （h） 1 cytokine interleukin （IL）-2 and Th2 cytokine IL-6 were detected by the quantitative sandwich enzyme immunoassay technique. Another group of HBV-transgenic mice was assigned to receive the effective ingredient of Styela plicata for consecutive weeks. The histology of liver tissue was evaluated before and after treatment. RESULTS： Twelve weeks after starting the therapy, serum hepatitis B surface antigen was significantly lowered in Styela plicata -treated mice and lamivudine-treated mice compared with the mice receiving normal diet （F12wk = 88.81, P12wk = 0.000 〈 0.01）. Serum HBV DNA was significantly lowered in Styela plicata -treated mice and lamivudine-treated mice compared with the mice receiving normal diet （F12wk = 20.71, P12wk = 0.000 〈 0.01）. However, like lamivudine, the effective ingredient of Styela plicata could not inhibit the replication of HBV completely. A rebound phenomenon of hepatitis B surface antigen and HBV DNA in sera could be found 4 wk after withdrawal of medication. Eight weeks after starting the therapy, serum levels before and after Styela plicata treatment of IL-2 were 2.41 ± 0.38 and 10.56 ± 0.78 ng/L, respectively （t8wk = -16.51, P8wk = 0.000 〈 0.01）. Compared with the serum levels of IL-2 in the normal diet-treated mice （2.48 ± 0.17 ng/L; t8wk = 13.23, P8wk = 0.000 〈 0.01）. Serum levels before and after Styela plicata treatment of IL-6 were 63.62 ± 6.31 and 54.52 ± 6.22 ng/L, respectively, compared with the serum levels of IL-6 in the normal diet-treated mice （60.84 ± 4.21 ng/L）. Histological analysis of liver from Styela plicata-treated HBV-transgenic mice also showed catabatic status in inflammation and hepatitis B surface antigen. CONCLUSION： Styela plicata may be an effective anviral medicine in treating chronic hepatitis B.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51902043)the China Postdoctoral Science Foundation(Grant No.2018M641704)+1 种基金and the Fundamental Research Funds for the Central Universities(Grant No.N180203018)This work was also partially supported by the National Natural Science Foundation of China(Grant Nos.51571058 and 51871048).
文摘The thickness dependence of mechanical properties of nacre in Cristaria plicata shell was studied under three-point bending tests.The results show that the mechanical behavior of nacre exhibits a strong thickness dependence.The bending strength firstly increases with the increase of specimen thickness and then becomes roughly constant as the thickness reaches a certain value of∼2.5mm.However,the mean value of work per unit volume increases constantly with increasing specimen thickness;meanwhile,the cracking mode changes from penetration into the platelets to deflection along the interfaces.The theoretical analyses indicate that the thickness-dependent mechanical properties of nacre are mainly caused by the variation in the number of inter-lamellar interfaces.The more the number of inter-lamellar interfaces is,the higher the strength and work of fracture of nacre under bending tests will be.However,as the number of inter-lamellar interfaces reaches a certain value(e.g.,in the present specimen with 2.5mm thickness),the strength tends to remain constant,while the work of fracture still increases.Therefore,the present research findings are expected to provide a valuable guidance for the interfacial design of nacre-like materials with high strength and toughness.
基金jointly supported by the National Natural Science Foundation of China (Nos. 51622901 , 51709225 )the Young Scientific Research Innovation Team Project of Xi'an University of Technology (No. 104/256051715 )。
文摘Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.
基金Supported by the Public Science and Technology Research Funds Projects of Ocean(No.201405040)the Key Research and Development Program in Shandong Province(No.2016GSF121034)the Jiangsu Provincial Key R&D Project(No.BE2015335)
文摘Agar,agarose,and agaropectin were extracted from the red alga Ahnfeltia plicata,and their properties and structures were characterized.Agar was extracted by a comparatively low alkaline consumption of 1.2%.It exhibited a gel strength of 1 152.50±74.25 g/cm^2 and a sulfate content of 0.55%±0.08%.The yield of agar from A.plicata was 24.53%,which is higher than those of other agarophytes commonly used in China.Three kinds of the method were compared for the purification of agarose,and the physicochemical properties of agarose that was prepared under the optimal condition were identical to those of commercially available agarose.Furthermore,agaropectin was purified from A.plicata and characterized by GC,HPLC,UV-spectrum,and FI-IR to understand its composition and structure.It was the first time to comprehensively study the agar and its fractions from the red alga of A.plicata.This research provided an eco-friendly agar extraction method from A.plicata and revealed its potential application for the production of agar,agarose,and agaropectin.
基金the National Natural Science Foundation of ChinaFoundation for the Doctoral Programme from State Education Commission of China
文摘Two new iridoid glycosides,plicatoside A and plicatoside B,were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaenoside by means of chemical evidence and spectral data.
基金Supported by the grants from the Social Development Program of Department of Science and Technology of Guangdong Province (2004B30101009).
文摘Objective:To evaluate the antiviral activity of the alcohol extract of Styela plicata on DHBV (duck hepatitis B virus) in vivo. Methods: Guangzhou-Sheldrake ducklings congenitally infected with DHBV were assigned to receive the alcohol extract of Styela plicata or lamivudine for 30 consecutive days. The DHBV DNA of sera was detected by RT-PCR. and the histological analysis of duckling liver was evaluated. Results:Thirty days after therapy,histological analysis of duckling liver showed that the ducklings receiving the alcohol extract of Styela plicata or lamivudine exhibited catabatic status in the degree of liver cell degeneration and inflammation compared with the ducklings receiving normal diet. DHBV DNA of sera from alcohol extract of Styela plicata-treated ducklings and lamivudine-treated ducklings all produced significantly lower levels compared with ducklings receiving normal diet (P<0. 01 ). Although these treatment groups all exhibited a rebound phenomenon 10 d after withdrawal of medication, they still exhibited a significant lower level of serum DHBV DNA compared with the control group responded to normal diet (P<0. 05, P<0. 01). Conclusion:Styela plicata may be an effective antiviral medicine in treating chronic hepatitis B. The data of this experiment will be valuable in studying the therapeutic role and the potential therapeutic mechanism of Styela plicata.
基金Supported by Science and Technology Project of Sichuan Province(2015-JY0226)
文摘[Objectives] To study in vitro antioxidant activity of extracts from Eleutherine plicata Herb by different extraction methods.[Methods]1,1-diphenyl-2-picrylhydrazyl( DPPH) free radical scavenging method,2,2'-Azinobis( 3-ehtylbenzothiazolin-6-sulfnic acid) diammonium salt( ABTS) free radical scavenging method,and iron ion reduction ability determination method were applied to measure the extracts of Eleutherine plicata Herb by ethanol extraction,water extraction,and ethanol extraction after water extraction,and comparison was made with positive control Vc( vitamin C). [Results]The ethanol extract,water extract,and ethanol extract after water extraction of Eleutherine plicata Herb had a high DPPH free radical,ABTS free radical scavenging activity,and reducing activity. [Conclusions]E. plicata Herb is a natural antioxidant with high potential.
文摘IT has been demonstrated that two reproductive hormones,gonadotropin-releasing hormone(GnRH)and gonadotropin(GTH),exist in the nervous system and Hatschek’s pit oflancelet,a species of Cephalochordata,and that these hormones are involved in the regulationof gonadal development and reproductive activity of lancelet.However,no report could
文摘Spathoglottis plicata Blume. is a horticulturally important vulnerable ground orchid with beautiful flowers blooming round the year. Highfrequency protocorm-like body(PLB) formation was established via callus culture from vegetative tissues of in vitro germinated seedlings of S.plicata. Media containing MS salts and Gamborg's B5 vitamins supplemented with 1.0 mg·L^(-1) 2,4-dichlorophenoxyacetic acid(2,4-D), 3.0 mg·L^(-1) α-naphthaleneacetic acid(NAA), 1.0 mg·L^(-1) kinetin(KIN), and 10%(v/v) ‘Aloe vera gel'(Av G) were effective in fragile calli induction. A maximum of(22.3 ± 0.52) PLBs were induced from about 250 mg callus within 45–55 days in the presence of 2.0 mg·L^(-1) NAA and 3.0 mg·L^(-1) 6-benzylaminopurine(BAP). Briefly, 3.0% sodium alginate was found to be most suitable for the formation of an appropriate shape and good germination rates(86.7%)of artificial seeds. Out of three different temperatures(4, 15, and 24 °C), the best result was achieved at 4 °C with 66.7% germinability even after90 days of storage. Plantlets were acclimatized with 86.6% survival rate and 76.3% of these plants produced flowers within 12–15 months of field transfer. Chromosomal studies revealed cytological stability of all regenerants containing 2 n = 40 chromosomes as in the parental plants.The present protocol can be applied reliably for the purposes of large-scale commercial propagation and short-term conservation of this orchid.
基金supported by the special grant of Chongqing University of Arts and Sciences for the person with ability
文摘Partial sequences of the mitochondrial 16S rRNA gene were determined for two Sesarma species （S. haematocheir and S. pficata）, and the length of sequence of S. haematocheir and S. plicata was the same. Of the 533 nucleotides obtained, the A, T, G and C contents were similar, which were 198 bp （37.1%）, 206 bp （38.6%）, 84 bp （15.8%）, 45 bp （8.4%） and 200 bp （37.5%）, 205 bp （38.5%）, 81 bp （15.2%）, 47 bp （8.8%） respectively. There were 49 different sites between the two species, including 21 transition sites, 22 transversion sites and 6 deletion/insertion sites. Furthermore, 361 bp homologous fragment was analyzed to discuss the phylogenetic relationship of 20 Sesarma species. The results showed that AT content （78.6% - 82.9%） was higher than GC content and there were 91 vadable positions of 16S rRNA sequences among the 20 species. Among 3 Sesarma species in China, S. dehaani and S. haematocheir were closely related （d=0.0151）; and there were greater genetic distances between S. pficata and S. dehaani I S. haematocheir （d=0.0924/0.0923）. The average genetic distances of S. plicata , S. dehaani and S. haematocheir with the North American crabs of genus Sesarma were respectively 0.103 2 ± 0.008 9, 0.0783±0.0105 and 0.072 0± 0.011, which indicated that there were greater genetic differences between China and North American Sesarma crabs and they were monophyletic each other.
