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
N-ethyl-N-nitrosourea （ENU） mutagenesis in mice can be used to study gene function in vivo and to establish genetic mouse models of human disease. In this study, a white spotted mouse （named Kit^W-1 Bao） was obtai...N-ethyl-N-nitrosourea （ENU） mutagenesis in mice can be used to study gene function in vivo and to establish genetic mouse models of human disease. In this study, a white spotted mouse （named Kit^W-1 Bao） was obtained by ENU-induced mutagenesis. Inheritance testing showed a single-gene dominant mutation and lethality in the Kit^W-1 Bao homozygous mice. The mutation was mapped to Chromosome 5 between markers DSMit356 and DSMit308. The region contains the Kit gene, whose mutations are known to lead to pigmentation defects in mice. Sequence analysis of the Kit cDNA from Kit^W-1 Bao heterozygotes revealed an A to T missense mutation resulting in an amino acid substitution of Asp （D） by Val （V） at amino acid position 849 within a highly conserved tyrosine kinase domain. The combined phenotype displayed by the Kit^W-1 Bao heterozygous and homozygous mutant mice demonstrates the critical function of the highly conserved aspartie acid residue at position 849 in the Kit gene product展开更多
Aedes albopictus is an important vector of arboviruses and prefers small containers of stagnant water as oviposition sites.One of the mechanisms mosquitoes use to search for suitable oviposition sites is relying on od...Aedes albopictus is an important vector of arboviruses and prefers small containers of stagnant water as oviposition sites.One of the mechanisms mosquitoes use to search for suitable oviposition sites is relying on odor cues from prospective sites and their surroundings.The genetic and molecular bases of this behavior are not known for Ae.albopictus.Oviposition site-searching behavior can be separated into 2 stages:container location and water detection.We applied a glue compound to the antennae and the maxillary palps of adult females to mask their ability to detect molecules that may guide them to preferred oviposition sites.Treatment of the antennae significantly reduces the location index(P<0.001),indicating a decreased ability to find oviposition sites,whereas no significant difference was observed in mosquitoes with maxillary palps treated with the same glue compound(P>0.05).The detection time,measured as the duration from contact with the water surface to the deposition of the first egg,was extended in mosquitoes with treated antennae or maxillary palps,supporting the conclusion that olfaction is involved in the detection of oviposition site.Transcriptomic analysis identified differentially expressed olfactory-related genes,including obp67,obp56d-like,obp19d-like and obp67-like.RNA interference(RNAi)-mediated knockdown of obp67 and obp56d-like significantly affected the location index and detection time,respectively.Cas9/guide RNA-mediated knockout of obp56d-like resulted in a prolonged detection time,compared with the wild type(P<0.05).These findings help to elucidate aspects of the olfactory mechanisms involved in Ae.albopictus oviposition site selection,and provide a basis for the development of mosquito surveillance and control strategies.展开更多
The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments.These regular rhythms are regulated by core clock genes and recent studies have also implicated rol...The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments.These regular rhythms are regulated by core clock genes and recent studies have also implicated roles for microRNAs in this regulation.Oviposition is an important circadian behavior in the reproductive cycle of insect vectors of diseases,and little is known about the rhythm or its regulation in mosquitoes.Aedes albopictus is a diurnal mosquito that transmits arboviruses and is the major cause of outbreaks of dengue fever in China.We analyzed the oviposition rhythm patterns of A.albopictus under different light/dark conditions and show that the mosquitoes have an oviposition peak between zeitgeber time 9(ZT 9)and ZT 12.Furthermore,the antagomir-mediated knockdown of expression of the microRNA miR-2940-1 affected the oviposition rhythm of A.albopictus.These data support the conclusion that miR-2940-1 is involved in the regulation of oviposition rhythm in A.albopictus and provide a foundation for using oviposition rhythms as a new target for vector mosquito control.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supported by the National Natural Science Foundation of China(NO.30670231)Public Service Project of Lab Animal Science(NO.2008F80005)SRF for ROCS,SEM
文摘N-ethyl-N-nitrosourea （ENU） mutagenesis in mice can be used to study gene function in vivo and to establish genetic mouse models of human disease. In this study, a white spotted mouse （named Kit^W-1 Bao） was obtained by ENU-induced mutagenesis. Inheritance testing showed a single-gene dominant mutation and lethality in the Kit^W-1 Bao homozygous mice. The mutation was mapped to Chromosome 5 between markers DSMit356 and DSMit308. The region contains the Kit gene, whose mutations are known to lead to pigmentation defects in mice. Sequence analysis of the Kit cDNA from Kit^W-1 Bao heterozygotes revealed an A to T missense mutation resulting in an amino acid substitution of Asp （D） by Val （V） at amino acid position 849 within a highly conserved tyrosine kinase domain. The combined phenotype displayed by the Kit^W-1 Bao heterozygous and homozygous mutant mice demonstrates the critical function of the highly conserved aspartie acid residue at position 849 in the Kit gene product
基金supported by grants from the National Natural Science Foundation of China(31830087 and 82261128003/2022YFML1001)the Key R&D Program of Guangdong Province(2022B1111030002)the National Institutes of Health,USA(AI136850)to X.-G.C.A.A.J.is a Donald Bren Professor at UCI.
文摘Aedes albopictus is an important vector of arboviruses and prefers small containers of stagnant water as oviposition sites.One of the mechanisms mosquitoes use to search for suitable oviposition sites is relying on odor cues from prospective sites and their surroundings.The genetic and molecular bases of this behavior are not known for Ae.albopictus.Oviposition site-searching behavior can be separated into 2 stages:container location and water detection.We applied a glue compound to the antennae and the maxillary palps of adult females to mask their ability to detect molecules that may guide them to preferred oviposition sites.Treatment of the antennae significantly reduces the location index(P<0.001),indicating a decreased ability to find oviposition sites,whereas no significant difference was observed in mosquitoes with maxillary palps treated with the same glue compound(P>0.05).The detection time,measured as the duration from contact with the water surface to the deposition of the first egg,was extended in mosquitoes with treated antennae or maxillary palps,supporting the conclusion that olfaction is involved in the detection of oviposition site.Transcriptomic analysis identified differentially expressed olfactory-related genes,including obp67,obp56d-like,obp19d-like and obp67-like.RNA interference(RNAi)-mediated knockdown of obp67 and obp56d-like significantly affected the location index and detection time,respectively.Cas9/guide RNA-mediated knockout of obp56d-like resulted in a prolonged detection time,compared with the wild type(P<0.05).These findings help to elucidate aspects of the olfactory mechanisms involved in Ae.albopictus oviposition site selection,and provide a basis for the development of mosquito surveillance and control strategies.
基金supported by grants from the Key R&D Program of Guangdong Province(2022B1111030002)the National Natural Science Foundation of China(31830087 and 82261128003/2022YFML1001)the National Institutes of Health,USA(AI136850)to X.-G.C.A.A.J.is a Donald Bren Professor at the University of California,Irvine.
文摘The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments.These regular rhythms are regulated by core clock genes and recent studies have also implicated roles for microRNAs in this regulation.Oviposition is an important circadian behavior in the reproductive cycle of insect vectors of diseases,and little is known about the rhythm or its regulation in mosquitoes.Aedes albopictus is a diurnal mosquito that transmits arboviruses and is the major cause of outbreaks of dengue fever in China.We analyzed the oviposition rhythm patterns of A.albopictus under different light/dark conditions and show that the mosquitoes have an oviposition peak between zeitgeber time 9(ZT 9)and ZT 12.Furthermore,the antagomir-mediated knockdown of expression of the microRNA miR-2940-1 affected the oviposition rhythm of A.albopictus.These data support the conclusion that miR-2940-1 is involved in the regulation of oviposition rhythm in A.albopictus and provide a foundation for using oviposition rhythms as a new target for vector mosquito control.
