Sea cucumbers play an important role in sediment bioturbation in coral reef and rocky intertidal ecosystems,and bacteria were a commonly-reported component of holothuroid diets.Bacterial community composition in the f...Sea cucumbers play an important role in sediment bioturbation in coral reef and rocky intertidal ecosystems,and bacteria were a commonly-reported component of holothuroid diets.Bacterial community composition in the foregut and hindgut of two common tropical sea cucumbers(Holothuria atra and H.leucospilota)and the ambient surface sediment were investigated using high throughput sequencing based on 16S rRNA gene analysis.A total of 5584 operational taxonomic units(OTUs)were obtained from 25 samples based on a 97%threshold,and more than half of the OTUs(n=3694,66.2%)were shared by the gut contents of two species of sea cucumbers and surrounding sediments.Bacterial richness and diversity in sediment samples were signifi cantly higher than those in the gut content samples(P<0.05).Proteobacteria was the predominant phylum in most samples showing 45.69%±8.61%,70.09%±4.03%,45.88%±5.38%,and 55.19%±0.79%reads in the foregut of H.leucospilota,hindgut of H.leucospilota,hindgut of H.atra,and sediment libraries,respectively,but Bacteroidetes was the predominant phylum with the relative content of 34.98%±5.52%in the foregut of H.atra.Among the dominant genera,reads related to the genera Anderseniella,Ilumatobacter,and Ruegeria were detected in all the gut contents and sediment libraries.A comparison of gut bacteria community between the two species of sea cucumbers suggested that H.atra had stronger feeding preference than H.leucospilota,and the same types of microbes escaped digestion of the two sea cucumber species.Obvious diff erent bacterial community composition in the foreguts of the two species of sea cucumbers and the surrounding sediments might result from the animal’s selective feeding for sediment patches.Bacterial community structure in hindgut contents of H.atra and H.leucospilota both diff ered clearly from adjacent sediments,which indicated feeding activity of deposit-feeding sea cucumbers could change the sedimental bacterial composition.In conclusion,from the perspective of bacteria,sea cucumber H.atra and H.leucospilota had diff erent feeding preferences,yet they could both aff ect bacterial composition in sediments by feeding activity.The motivation for selective feeding and sea cucumber-sediment interaction might be explored in the future.展开更多
To study the expression of the carboxy-ter-minal PSD-95/DLG/ZO-1 ligand of nNOS(CAPON)and Dexras1 mRNA during development in the spinal cord of rats,real-time polymerase chain reaction(Real-time PCR),as a quantitative...To study the expression of the carboxy-ter-minal PSD-95/DLG/ZO-1 ligand of nNOS(CAPON)and Dexras1 mRNA during development in the spinal cord of rats,real-time polymerase chain reaction(Real-time PCR),as a quantitative method,was used to study the developmental expression of CAPON and Dexras1 mRNA level in the spinal cord.The spatial expression of CAPON and Dexras1 mRNA was examined by a com-bination of in situ hybridization(ISH)and immunofluor-escence.During the development of the spinal cord,CAPON mRNA was expressed in low levels from embryo day 14 to day 18.At postnatal day 1,it reached the peak and was expressed in the part which will become the dor-sal horn when mature.It then decreased gradually until postnatal week 12,when it presented in the ventral horn.At embryo day 14,Dexras1 mRNA was expressed at low levels,increased during embryo day 16 to day 18 and peaked at postnatal day 1.Spatiotemporal expression of Dexras1 mRNA was similar to CAPON as confirmed by correlation analysis and colocalization.CAPON and neuronal nitric oxide synthase(nNOS)was expressed within the same cells of the dorsal horn at postnatal day 1 but had different subcellular localizations.Co-express-ion of CAPON and Dexras1 mRNA in myeloid tissue during development process of rat indicates that the adaptor protein,CAPON may play a probable role in differentiation of neurons,synaptic plasticity and synap-togenesis by regulating nNOS to activate Dexras1.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41766005,31760757)the National Key Research and Development Program of China(No.2019YFD0901304)。
文摘Sea cucumbers play an important role in sediment bioturbation in coral reef and rocky intertidal ecosystems,and bacteria were a commonly-reported component of holothuroid diets.Bacterial community composition in the foregut and hindgut of two common tropical sea cucumbers(Holothuria atra and H.leucospilota)and the ambient surface sediment were investigated using high throughput sequencing based on 16S rRNA gene analysis.A total of 5584 operational taxonomic units(OTUs)were obtained from 25 samples based on a 97%threshold,and more than half of the OTUs(n=3694,66.2%)were shared by the gut contents of two species of sea cucumbers and surrounding sediments.Bacterial richness and diversity in sediment samples were signifi cantly higher than those in the gut content samples(P<0.05).Proteobacteria was the predominant phylum in most samples showing 45.69%±8.61%,70.09%±4.03%,45.88%±5.38%,and 55.19%±0.79%reads in the foregut of H.leucospilota,hindgut of H.leucospilota,hindgut of H.atra,and sediment libraries,respectively,but Bacteroidetes was the predominant phylum with the relative content of 34.98%±5.52%in the foregut of H.atra.Among the dominant genera,reads related to the genera Anderseniella,Ilumatobacter,and Ruegeria were detected in all the gut contents and sediment libraries.A comparison of gut bacteria community between the two species of sea cucumbers suggested that H.atra had stronger feeding preference than H.leucospilota,and the same types of microbes escaped digestion of the two sea cucumber species.Obvious diff erent bacterial community composition in the foreguts of the two species of sea cucumbers and the surrounding sediments might result from the animal’s selective feeding for sediment patches.Bacterial community structure in hindgut contents of H.atra and H.leucospilota both diff ered clearly from adjacent sediments,which indicated feeding activity of deposit-feeding sea cucumbers could change the sedimental bacterial composition.In conclusion,from the perspective of bacteria,sea cucumber H.atra and H.leucospilota had diff erent feeding preferences,yet they could both aff ect bacterial composition in sediments by feeding activity.The motivation for selective feeding and sea cucumber-sediment interaction might be explored in the future.
基金This work was supported by the National Natural Science Foundation of China(Grant No.30300099,Grant No.30770488)Natural Science Foundation of Jiangsu Province(No.BK2003035,No.BK2006547)and"Six Talent Peak"Foundation of Jiangsu Province.
文摘To study the expression of the carboxy-ter-minal PSD-95/DLG/ZO-1 ligand of nNOS(CAPON)and Dexras1 mRNA during development in the spinal cord of rats,real-time polymerase chain reaction(Real-time PCR),as a quantitative method,was used to study the developmental expression of CAPON and Dexras1 mRNA level in the spinal cord.The spatial expression of CAPON and Dexras1 mRNA was examined by a com-bination of in situ hybridization(ISH)and immunofluor-escence.During the development of the spinal cord,CAPON mRNA was expressed in low levels from embryo day 14 to day 18.At postnatal day 1,it reached the peak and was expressed in the part which will become the dor-sal horn when mature.It then decreased gradually until postnatal week 12,when it presented in the ventral horn.At embryo day 14,Dexras1 mRNA was expressed at low levels,increased during embryo day 16 to day 18 and peaked at postnatal day 1.Spatiotemporal expression of Dexras1 mRNA was similar to CAPON as confirmed by correlation analysis and colocalization.CAPON and neuronal nitric oxide synthase(nNOS)was expressed within the same cells of the dorsal horn at postnatal day 1 but had different subcellular localizations.Co-express-ion of CAPON and Dexras1 mRNA in myeloid tissue during development process of rat indicates that the adaptor protein,CAPON may play a probable role in differentiation of neurons,synaptic plasticity and synap-togenesis by regulating nNOS to activate Dexras1.
