Arbuscular mycorrhizal fungi （AMF） have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition ...Arbuscular mycorrhizal fungi （AMF） have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony （Sb）. The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis （PCR-DGGE）. Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis （PC_A） indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis （RDA） showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Gloraus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.展开更多
We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS seq...We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS sequences showed slight nucleotide divergences between Enteromorpha linza and Enteromorpha prolifera.In contrast,multiple highly variable regions were found in the ITS region of Enteromorpha flexuosa.In general,there were more variable sites in the NTS region than in the ITS region in the three species.The variations in 5S rDNA NTS sequences indicated that the molecular diversity of Enteromorpha from the coast of Yantai is very high.However,a phylogenetic tree constructed using 5S rDNA NTS sequence data indicated that genetic differences were not directly related to geographical distribution.展开更多
The Human Immunodeficiency Virus (HIV) has a diversity that is equal to the complexity of its management. The group M (Major) is the dominant group in Sub-Saharan Africa and its distribution is very heterogeneous;the ...The Human Immunodeficiency Virus (HIV) has a diversity that is equal to the complexity of its management. The group M (Major) is the dominant group in Sub-Saharan Africa and its distribution is very heterogeneous;the diversity of the virus is more heterogeneous in this region than elsewhere in the world which follows a complex and specific algorithm because of geographical positions and countries. This distribution is very dynamic, evolving and unpredictable. This review aimed to expose the specifics of the HIV Type 1 epidemic in Central Africa, in terms of the different molecular variants of HIV published for the region compared to the geographic location. Both Type 1 and Type 2 of HIV are prevalent in sub-Saharan Africa due to distinct geographical contexts. HIV-2 is mainly documented in West and Central Africa, particularly in Cameroon, Guinea-Bissau, Gambia, Senegal, Ivory Coast and Burkina-Faso however HIV-1 infection is widely distributed across the continent. The HIV-1 epidemic in Sub-Saharan Africa is dominated by the Group M. The different subtypes respect a certain geographical distribution across the continent. West Africa is dominated by subtype A, East and South Africa are dominated by subtype C, while Central Africa is dominated by strains A, C, D, F, H, J, CRF01-AE and CRF02-AG. This review is the first to present de molecular diversity of HIV-1 in metropolitan cities in all central African countries. The Circulating Recombinant Form (CRF02_AG) and subtypes A and G are present in all Central African countries and are also the most commonly encountered;followed by the subtypes D, F, G, C, B, J, K and several Circulating Recombinant Forms that are not represented in all Central African countries.展开更多
Metabolites from marine organisms have proven to be a rich source for the discovery of multiple potent bioactive moleculeswith diverse structures. In recent years, we initiated a program to investigate the diversity o...Metabolites from marine organisms have proven to be a rich source for the discovery of multiple potent bioactive moleculeswith diverse structures. In recent years, we initiated a program to investigate the diversity of the secondary metabolites frommarine invertebrates and their symbiotic microorganisms collected from the South China Sea. In this review, representativecases are summarized focusing on molecular diversity, mining, and application of natural products from these marineorganisms. To provide a comprehensive introduction to the field of marine natural products, we highlight typical moleculesincluding their structures, chemical synthesis, bioactivities and mechanisms, structure-activity relationships as well as biogenesis. The mining of marine-derived microorganisms to produce novel secondary metabolites is also discussed through theOSMAC strategy and via partial chemical epigenetic modification. A broad prospectus has revealed a plethora of bioactivenatural products with novel structures from marine organisms, especially from soft corals, gorgonians, sponges, and theirsymbiotic fungi and bacteria.展开更多
Coastal wetlands store large amounts of soil organic carbon(SOC),and have assumed key roles in mitigating increasing CO_(2)in the atmosphere.The ongoing debate about SOC stabilization mechanisms stems partly from our ...Coastal wetlands store large amounts of soil organic carbon(SOC),and have assumed key roles in mitigating increasing CO_(2)in the atmosphere.The ongoing debate about SOC stabilization mechanisms stems partly from our incomplete understanding of its complex chemical architecture at the molecular scale.Deciphering the molecular composition of soil organic matter is crucial for revealing mechanisms that govern SOC persistence.This study utilized the field sampling data from 2016 and aimed to characterize molecular composition of SOC in typical salt marsh(SM)and freshwater marsh(FM)in Louisiana coastal regions,USA by extending the application of graph networks with pyrolysis-gas chromatography-mass spectrometry,and then to quantify potential links between SOC persistence and molecular diversity and network complexity.The results revealed that SOC predominantly consisted of alkyl compounds(Alkyl),phenol(Ph),lignin(Lg),and aliphatic compounds,constituting 23.21%and 27.85%,17.84%and 21.55%,16.94%and 15.49%,17.20%and 15.93%of total ion chromatogram(TIC)in SM and FM wetlands,respectively.Molecular diversity in SM was higher than that in FM,while the network graph exhibited greater complexity in FM,featuring 167 and 123 nodes,and 1935 and 1982 edges in the network graphs of SOC from SM and FM,respectively.Correlation analysis confirmed positive relations between molecular diversity indices,network complexity,and abundance of stable carbon isotopes(δ^(13)C).The variance partitioning analysis(VPA)supplied that soil nutrients exerted the most significant control on SOC persistence.Molecular diversity and network complexity,when combined with soil nutrients,could explain 34%of the variances in SOC persistence.展开更多
Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was propo...Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.展开更多
Because of the limitations of sampling and seasonal study in polar regions, knowledge of dinoflagellate diversity, distribution and ecology are limited. Dinoflagellates have been incidentally reported from polar regio...Because of the limitations of sampling and seasonal study in polar regions, knowledge of dinoflagellate diversity, distribution and ecology are limited. Dinoflagellates have been incidentally reported from polar regions during some seasons and some populations have been reported as components of microalgae. Surveys of molecular diversity link the genotype of dinoflagellates from polar regions with environmental adaptation. In this study, 37 positive clones of dinoflagellates collected from different sites were used for genotype analysis, providing new insights into the biodiversity and distribution of these species based on 18S rRNA sequencing. Diverse genotypes were recorded for the summer season in Kongsfjorden （high Arctic） whilst a single novel genotype of dinoflagellate was recorded from winter samples from the Antarctic Ocean. Data from ice cores suggests that this single dinoflagellate genotype was adapted to extreme cold and clone library screening found that it was occasionally the only microbial eukaryotic genotype found in winter ice cores. The findings of this study could improve our understanding of the diverse dinoflagellate genotypes occurring in these perennially cold microbial ecosystems.展开更多
Indo-Burmese region was the primary center of eggplant diversity from where the crop extended to several secondary origins of diversity.In this study,the genetic diversity among fifty-six eggplant accessions collected...Indo-Burmese region was the primary center of eggplant diversity from where the crop extended to several secondary origins of diversity.In this study,the genetic diversity among fifty-six eggplant accessions collected from three countries was assessed using sixteen polymorphic SSR markers to determine suitable parents for heterotic hybridization.The estimation of genetic diversity among the population of three countries(Bangladesh,Malaysia,and Thailand)varied from 0.57 to 0.74,with Shannon’s index value of 0.65.The mean value of expected heterozygosity and Nei’s index was 0.49,with an average PIC value of 0.83.A dendrogram was constructed based on UPGMA(unweighted pair group method with arithmetic mean),and the dendrogram categorized all accessions into six groups.The AMOVA(analysis of molecular variance)revealed a 77%total variation within the population from three different countries and 23%total variation among the populations.The result revealed a high genetic differentiation among the eggplant germplasms while the accessions that are farther from each other show a high level of diversity;thus,they can be recommended as parental in breeding programs.Hence,accessions,EB12,ET11,ET13,ET15,ET16,and ET17 could be crossed with accessions EM3,EB34,and EB3 for improvement in the future breeding program.展开更多
To study the efficiency ofDNA gyrase subunit B （gyrB） gene as means of diversity analysis, diversities of gyrB genes in three AMD samples collected from Dabaoshan Mine were studied by analyzing gyrB gene library. Ma...To study the efficiency ofDNA gyrase subunit B （gyrB） gene as means of diversity analysis, diversities of gyrB genes in three AMD samples collected from Dabaoshan Mine were studied by analyzing gyrB gene library. Many novel gyrB sequences and groups were detected. The results show that Acidithiobacillusferrooxidans-like bacteria represented 88.0% of the bacterial population in a sample. However, other two samples showed much high diversities. These diversities were characterized by the reciprocal of Simpson＇s index （l/D）, and show ferrous ion strongly influenced the composition of the microbial communities. The study indicate that gyrB Gene as a phylogenetic discriminator is a good tool to study different strains in same species that were difficult to be distinguished by 16S genes. But now gyrB Gene cannot define clearly unknown sequences to certain lineage, due to the incompleteness of the gyrB database.展开更多
A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat（SSR） and inter simple sequence repeat（ISSR） markers to study genetic divers...A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat（SSR） and inter simple sequence repeat（ISSR） markers to study genetic diversity and population structure. Following unweighted pair group method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 5 clusters and 11 sub-clusters, whereas population structure analysis separated 50 rice genotypes into 5 sub-populations. Grouping of rice genotypes showed better resemblance with the pedigree information of the genotypes. Both genetic diversity and population structure analysis separated majority of the improved varieties from landraces and local selections. Some of the SSR markers amplified unique alleles which were specific to a particular genotype and could distinguish them from the rest. The results indicate that these rice genotypes exhibit a higher genetic diversity and can be very useful in rice improvement program.展开更多
Molecular diversity and development of the Lactobacillus community in the intestinal tract, as influenced by age and intestinal compartment, were studied in one litter of 12 conventionally raised piglets. Piglets were...Molecular diversity and development of the Lactobacillus community in the intestinal tract, as influenced by age and intestinal compartment, were studied in one litter of 12 conventionally raised piglets. Piglets were euthanized at each week （3 animals per time）. Digesta and tissue samples from stomach, duodenum, jejunum, ileum, caecum, colon, and rectum were collected and analysed by using 16S ribosomal RNA-based methods. DGGE （denaturing gradient gel electrophoresis） profiles revealed that the Lactobacillus communities throughout the GI tract from duodenum to rectum showed good stability at same age. This indicates that fecal Lactobacillus communities can effectively represent the intestinal community. Two dominant bands were found in tissue samples of the small intestine, suggesting that the lactobacilli can adhere to the small intestinal wall. The Lactobacillus communities in different GI tract compartments developed over time. A successional change of Lactobacillus communities was observed from birth, through creep feeding to one week after weaning, showing a trend from simple to complex and back to simple. Furthermore, a clone library of Lactobacillus spp. 16S rRNA gene sequences were generated from jejunal and colonic chymes. Six dominant DGGE bands generated from jejunal chymes were matched with sequences that show 94-98% similarity to the bands derived from L. reuteri, L. delbrueckii, and L. crispatus. Seven dominant DGGE bands generated from colon chymes were matched with sequences that show 88-99% similarity to those derived from L. reuteri, L. delbrueckii, L. amylovorus/L. sobrius, and L. acidophilus. Amplicons related to L. reuteri were found in all DGGE fingerprints from jejunal digesta of age of weeks 1, 3, and 4. Amplicons related to L. amylovorus/L. sobrius were present in all DGGE fingerprints from colonic digesta of age of week 1, 3, and 4. Amplicons related to L. delbrueckii were found before weaning, L. crispatus after creep feeding before weaning and L. acidophilus after weaning. This indicates that L. reuteri and L. amylovorus/L. sobrius probably belong to the permanent composition, while L. delbruckii, L. acidophilus, and L. crispatus probably belong to the temporal groups of Lactobacillus communities in the GI tract of piglets.展开更多
Schistosomiasis is a public health concern in Benin. Freshwater snails of the genus Bulinus serve as intermediate hosts for schistosomes, trematode parasites responsible for bilharzia. The urinary form, caused by Schi...Schistosomiasis is a public health concern in Benin. Freshwater snails of the genus Bulinus serve as intermediate hosts for schistosomes, trematode parasites responsible for bilharzia. The urinary form, caused by Schistosoma haematobium, is the most widespread and is transmitted to humans by these mollusks, with Bulinus truncatus and Bulinus globosus being the most important species. Effective strategies to combat the transmission of these parasites require a prior understanding of the molecular characterization of Bulinus snails. For this purpose, 293 Bulinus snails were collected and morphologically identified from two localities in southern Benin, Sô-Ava and Azowlissè. The snails were preserved in absolute alcohol. To achieve the set objectives, DNA was extracted from the collected biological material, and SSU gene fragments were amplified. Using PCR-RFLP, the amplified fragments were digested with the restriction endonucleases HaeIII, HinfI, and DdeI to perform molecular characterization. In this study, 80 individuals of B. globosus and 10 of B. truncatus were subjected to molecular analysis. The PCR-RFLP profiles showed bands of different sizes for the Bulinus species when analyzed with the three endonucleases using the SSU molecular marker. PCR-RFLP analysis revealed that the snails belonged to the freshwater genus Bulinus, including Bulinus globosus and B. truncatus, based on reference profiles from studies conducted in Nigeria, which enabled precise identification of these gastropods. This study provided initial insights, although still incomplete, into the molecular diversity of these species.展开更多
Presented herein is a condition-controlled selective synthesis of CF_(3)-chromene and CF_(3)-benzofuran based on the reaction of N-phenoxyacetamide and CF_(3)-ynone.When the reaction is carried out in MeOH under the c...Presented herein is a condition-controlled selective synthesis of CF_(3)-chromene and CF_(3)-benzofuran based on the reaction of N-phenoxyacetamide and CF_(3)-ynone.When the reaction is carried out in MeOH under the catalysis of Rh(III),CF_(3)-chromene is formed via C—H metalation-initiated alkenylation,acetamide group migration and intramolecular oxo-nucleophilic addition.On the other hand,when the reaction is run in DMSO under the promotion of CsOAc,CF_(3)-benzofuran is generated via aza-Michael addition-initiated[3,3]-σrearrangement,intramolecular oxo-nucleophilic addition and water elimination.To our knowledge,this is the first report on the selective construction of chromene or benzofuran scaffold along with introduction of a CF_(3) unit from the same starting materials.The methodology was scalable and the products could be readily transformed into other valuable products.Moreover,the products thus obtained possess decent anticancer activity.展开更多
A direct and structurally divergent synthesis of indole alkaloids from very simple 2-vinylanilines, alkynes and TBN via a novel substrate flag- mentation/cycloaddition strategy has been developed, which provides an ef...A direct and structurally divergent synthesis of indole alkaloids from very simple 2-vinylanilines, alkynes and TBN via a novel substrate flag- mentation/cycloaddition strategy has been developed, which provides an efficient noble-metal-free approach to access a library of highly valuable indole derivatives of tryptamines and tryptamine-related oximes, lactams, and lactones, as well as β-carbolines, spiroindolines, and hexa-hydropyrrolo[2,3-b]- indoles.展开更多
Natural products derived from marine microorganisms have received great attention as a potential resource of new compound entities for drug discovery.The unique marine environment brings us a large group of sulfur-con...Natural products derived from marine microorganisms have received great attention as a potential resource of new compound entities for drug discovery.The unique marine environment brings us a large group of sulfur-containing natural products with abundant biological functionality including antitumor,antibiotic,anti-inflammatory and antiviral activities.We reviewed all the 484 sulfur-containing natural products(non-sulfated)isolated from marine microorganisms,of which 59.9%are thioethers,29.8%are thiazole/thiazoline-containing compounds and 10.3%are sulfoxides,sulfones,thioesters and many others.A selection of 133 compounds was further discussed on their structure-activity relationships,mechanisms of action,biosynthesis,and druggability.This is the first systematic review on sulfur-containing natural products from marine microorganisms conducted from January 1987,when the first one was reported,to December 2020.展开更多
An unprecedented copper nitrate-mediated bond cleavage of alkynes was developed for the modular synthesis of isoxazoles,where either C—S bond or C≡C triple bond was cleaved selectively.Substituents attached to the C...An unprecedented copper nitrate-mediated bond cleavage of alkynes was developed for the modular synthesis of isoxazoles,where either C—S bond or C≡C triple bond was cleaved selectively.Substituents attached to the C≡C triple bonds could differentiate the chemical bonds cleavage and reaction pathways disparately.Various transformations of products illustrate promising applications of the given protocols.展开更多
The effect of anthropogenic landscape fragmentation on the genetic diversity and adaptive potential of plant populations is a major issue in conservation biology.However,little is known about the partitioning of genet...The effect of anthropogenic landscape fragmentation on the genetic diversity and adaptive potential of plant populations is a major issue in conservation biology.However,little is known about the partitioning of genetic diversity in alpine species,which occur in naturally fragmented habitats.Here,we investigate molecular patterns of three alpine plants(Epilobium fleischeri,Geum reptans and Campanula thyrsoides)across Switzerland and ask whether spatial isolation has led to high levels of population differentiation,increasing over distance,and a decrease of within-population variability.We further hypothesize that the contrasting potential for long-distance dispersal(LDD)of seed in these species will considerably influence and explain diversity partitioning.Methods For each study species,we sampled 20–23 individuals from each of 20–32 populations across entire Switzerland.We applied Random Amplified Polymorphic Dimorphism markers to assess genetic diversity within(Nei’s expected heterozygosity,He;percentage of polymorphic bands,Pp)and among(analysis of molecular variance,Ust)populations and correlated population size and altitude with within-population diversity.Spatial patterns of genetic relatedness were investigated using Mantel tests and standardized major axis regression as well as unweighted pair group method with arithmetic mean cluster analyses and Monmonier’s algorithm.To avoid known biases,we standardized the numbers of populations,individuals and markers using multiple random reductions.We modelled LDD with a high alpine wind data set using the terminal velocity and height of seed release as key parameters.Additionally,we assessed a number of important life-history traits and factors that potentially influence genetic diversity partitioning(e.g.breeding system,longevity and population size).Important findings For all three species,we found a significant isolation-by-distance relationship but only a moderately high differentiation among populations(Ust:22.7,14.8 and 16.8%,for E.fleischeri,G.reptans and C.thyrsoides,respectively).Within-population diversity(He:0.19–0.21,Pp:62–75%)was not reduced in comparison to known results from lowland species and even small populations with<50 reproductive individuals contained high levels of genetic diversity.We further found no indication that a high long-distance seed dispersal potential enhances genetic connectivity among populations.Gene flow seems to have a strong stochastic component causing large dissimilarity between population pairs irrespective of the spatial distance.Our results suggest that other life-history traits,especially the breeding system,may play an important role in genetic diversity partitioning.We conclude that spatial isolation in the alpine environment has a strong influence on population relatedness but that a number of factors can considerably influence the strength of this relationship.展开更多
An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C_(3)-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromopheny...An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C_(3)-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromophenyl)acrylamides and organoboron reagents was successfully developed by using a 1,3-bis(2,6-diisopropylphenyl)acenaphthoimidazol-2-ylidene(AnIPr)-ligated oxazoline palladacycle.It enabled a very broad substrate scope tolerating different functional groups,electronic properties and steric bulkiness.Notably,it revealed a great potential to build diverse heterocycle-fused indoline alkaloids via the same intermediate 3-allyl-1,3-dimethylindolin-2-one.展开更多
基金supported by grants from the National Natural Science Foundation of China (Nos 41271338, 41303066)the Special Environmental Protection Foundation for Public Welfare Projects (No. 201009032)+1 种基金the National Science Foundation for Post-doctoral Scientists of China (No. 2013M530685)the State Key Laboratory Program (No. SKLECRA2013OFP03)
文摘Arbuscular mycorrhizal fungi （AMF） have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony （Sb）. The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis （PCR-DGGE）. Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis （PC_A） indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis （RDA） showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Gloraus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.
基金Supported by the National Key Technology Research and Development Program(No.2008BA49B01)the Key Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-209)
文摘We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS sequences showed slight nucleotide divergences between Enteromorpha linza and Enteromorpha prolifera.In contrast,multiple highly variable regions were found in the ITS region of Enteromorpha flexuosa.In general,there were more variable sites in the NTS region than in the ITS region in the three species.The variations in 5S rDNA NTS sequences indicated that the molecular diversity of Enteromorpha from the coast of Yantai is very high.However,a phylogenetic tree constructed using 5S rDNA NTS sequence data indicated that genetic differences were not directly related to geographical distribution.
文摘The Human Immunodeficiency Virus (HIV) has a diversity that is equal to the complexity of its management. The group M (Major) is the dominant group in Sub-Saharan Africa and its distribution is very heterogeneous;the diversity of the virus is more heterogeneous in this region than elsewhere in the world which follows a complex and specific algorithm because of geographical positions and countries. This distribution is very dynamic, evolving and unpredictable. This review aimed to expose the specifics of the HIV Type 1 epidemic in Central Africa, in terms of the different molecular variants of HIV published for the region compared to the geographic location. Both Type 1 and Type 2 of HIV are prevalent in sub-Saharan Africa due to distinct geographical contexts. HIV-2 is mainly documented in West and Central Africa, particularly in Cameroon, Guinea-Bissau, Gambia, Senegal, Ivory Coast and Burkina-Faso however HIV-1 infection is widely distributed across the continent. The HIV-1 epidemic in Sub-Saharan Africa is dominated by the Group M. The different subtypes respect a certain geographical distribution across the continent. West Africa is dominated by subtype A, East and South Africa are dominated by subtype C, while Central Africa is dominated by strains A, C, D, F, H, J, CRF01-AE and CRF02-AG. This review is the first to present de molecular diversity of HIV-1 in metropolitan cities in all central African countries. The Circulating Recombinant Form (CRF02_AG) and subtypes A and G are present in all Central African countries and are also the most commonly encountered;followed by the subtypes D, F, G, C, B, J, K and several Circulating Recombinant Forms that are not represented in all Central African countries.
基金supported by the National NaturalScience Foundation of China (nos. 4183053581673350+2 种基金U1706210)the Fundamental Research Funds for the Central Universities of China(no. 201962002)the Taishan Scholars Program, China.
文摘Metabolites from marine organisms have proven to be a rich source for the discovery of multiple potent bioactive moleculeswith diverse structures. In recent years, we initiated a program to investigate the diversity of the secondary metabolites frommarine invertebrates and their symbiotic microorganisms collected from the South China Sea. In this review, representativecases are summarized focusing on molecular diversity, mining, and application of natural products from these marineorganisms. To provide a comprehensive introduction to the field of marine natural products, we highlight typical moleculesincluding their structures, chemical synthesis, bioactivities and mechanisms, structure-activity relationships as well as biogenesis. The mining of marine-derived microorganisms to produce novel secondary metabolites is also discussed through theOSMAC strategy and via partial chemical epigenetic modification. A broad prospectus has revealed a plethora of bioactivenatural products with novel structures from marine organisms, especially from soft corals, gorgonians, sponges, and theirsymbiotic fungi and bacteria.
基金Under the auspices of National Natural Science Foundation of China(No.42371061,U20A2083)。
文摘Coastal wetlands store large amounts of soil organic carbon(SOC),and have assumed key roles in mitigating increasing CO_(2)in the atmosphere.The ongoing debate about SOC stabilization mechanisms stems partly from our incomplete understanding of its complex chemical architecture at the molecular scale.Deciphering the molecular composition of soil organic matter is crucial for revealing mechanisms that govern SOC persistence.This study utilized the field sampling data from 2016 and aimed to characterize molecular composition of SOC in typical salt marsh(SM)and freshwater marsh(FM)in Louisiana coastal regions,USA by extending the application of graph networks with pyrolysis-gas chromatography-mass spectrometry,and then to quantify potential links between SOC persistence and molecular diversity and network complexity.The results revealed that SOC predominantly consisted of alkyl compounds(Alkyl),phenol(Ph),lignin(Lg),and aliphatic compounds,constituting 23.21%and 27.85%,17.84%and 21.55%,16.94%and 15.49%,17.20%and 15.93%of total ion chromatogram(TIC)in SM and FM wetlands,respectively.Molecular diversity in SM was higher than that in FM,while the network graph exhibited greater complexity in FM,featuring 167 and 123 nodes,and 1935 and 1982 edges in the network graphs of SOC from SM and FM,respectively.Correlation analysis confirmed positive relations between molecular diversity indices,network complexity,and abundance of stable carbon isotopes(δ^(13)C).The variance partitioning analysis(VPA)supplied that soil nutrients exerted the most significant control on SOC persistence.Molecular diversity and network complexity,when combined with soil nutrients,could explain 34%of the variances in SOC persistence.
基金AGER-Fondazioni in rete per la ricerca agroalimentare(https://www.progettoager.it/)(Grant No.2010-2369)by Joint Programming Initiative on Agriculture,Food Security and Climate Change(FACCE-JPI)project Green Rice(Sustainable and environmental friendly rice cultivation systems in Europe).
文摘Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.
基金supported by the National Natural Science Foundation of China ( Grant No. 40806073, 40876097)Shanghai Rising-Star Program (Grant No. 11QA1407300)the Youth Marine Science Foundation of State Oceanic Administration(Grant no. 2008128)
文摘Because of the limitations of sampling and seasonal study in polar regions, knowledge of dinoflagellate diversity, distribution and ecology are limited. Dinoflagellates have been incidentally reported from polar regions during some seasons and some populations have been reported as components of microalgae. Surveys of molecular diversity link the genotype of dinoflagellates from polar regions with environmental adaptation. In this study, 37 positive clones of dinoflagellates collected from different sites were used for genotype analysis, providing new insights into the biodiversity and distribution of these species based on 18S rRNA sequencing. Diverse genotypes were recorded for the summer season in Kongsfjorden （high Arctic） whilst a single novel genotype of dinoflagellate was recorded from winter samples from the Antarctic Ocean. Data from ice cores suggests that this single dinoflagellate genotype was adapted to extreme cold and clone library screening found that it was occasionally the only microbial eukaryotic genotype found in winter ice cores. The findings of this study could improve our understanding of the diverse dinoflagellate genotypes occurring in these perennially cold microbial ecosystems.
基金the Malaysia Ministry of Education’s for the Long-Term Research Grant Scheme(LRGS)on Sustainable vegetable production technology for food security in urban agriculture(LRGS/1/2019/UKM/01/5/4).
文摘Indo-Burmese region was the primary center of eggplant diversity from where the crop extended to several secondary origins of diversity.In this study,the genetic diversity among fifty-six eggplant accessions collected from three countries was assessed using sixteen polymorphic SSR markers to determine suitable parents for heterotic hybridization.The estimation of genetic diversity among the population of three countries(Bangladesh,Malaysia,and Thailand)varied from 0.57 to 0.74,with Shannon’s index value of 0.65.The mean value of expected heterozygosity and Nei’s index was 0.49,with an average PIC value of 0.83.A dendrogram was constructed based on UPGMA(unweighted pair group method with arithmetic mean),and the dendrogram categorized all accessions into six groups.The AMOVA(analysis of molecular variance)revealed a 77%total variation within the population from three different countries and 23%total variation among the populations.The result revealed a high genetic differentiation among the eggplant germplasms while the accessions that are farther from each other show a high level of diversity;thus,they can be recommended as parental in breeding programs.Hence,accessions,EB12,ET11,ET13,ET15,ET16,and ET17 could be crossed with accessions EM3,EB34,and EB3 for improvement in the future breeding program.
文摘To study the efficiency ofDNA gyrase subunit B （gyrB） gene as means of diversity analysis, diversities of gyrB genes in three AMD samples collected from Dabaoshan Mine were studied by analyzing gyrB gene library. Many novel gyrB sequences and groups were detected. The results show that Acidithiobacillusferrooxidans-like bacteria represented 88.0% of the bacterial population in a sample. However, other two samples showed much high diversities. These diversities were characterized by the reciprocal of Simpson＇s index （l/D）, and show ferrous ion strongly influenced the composition of the microbial communities. The study indicate that gyrB Gene as a phylogenetic discriminator is a good tool to study different strains in same species that were difficult to be distinguished by 16S genes. But now gyrB Gene cannot define clearly unknown sequences to certain lineage, due to the incompleteness of the gyrB database.
文摘A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat（SSR） and inter simple sequence repeat（ISSR） markers to study genetic diversity and population structure. Following unweighted pair group method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 5 clusters and 11 sub-clusters, whereas population structure analysis separated 50 rice genotypes into 5 sub-populations. Grouping of rice genotypes showed better resemblance with the pedigree information of the genotypes. Both genetic diversity and population structure analysis separated majority of the improved varieties from landraces and local selections. Some of the SSR markers amplified unique alleles which were specific to a particular genotype and could distinguish them from the rest. The results indicate that these rice genotypes exhibit a higher genetic diversity and can be very useful in rice improvement program.
基金supported by the National Natural Science Foundation of China (30771570)the Natural Science Foundation of Jiangsu Province, China(BK2006143)
文摘Molecular diversity and development of the Lactobacillus community in the intestinal tract, as influenced by age and intestinal compartment, were studied in one litter of 12 conventionally raised piglets. Piglets were euthanized at each week （3 animals per time）. Digesta and tissue samples from stomach, duodenum, jejunum, ileum, caecum, colon, and rectum were collected and analysed by using 16S ribosomal RNA-based methods. DGGE （denaturing gradient gel electrophoresis） profiles revealed that the Lactobacillus communities throughout the GI tract from duodenum to rectum showed good stability at same age. This indicates that fecal Lactobacillus communities can effectively represent the intestinal community. Two dominant bands were found in tissue samples of the small intestine, suggesting that the lactobacilli can adhere to the small intestinal wall. The Lactobacillus communities in different GI tract compartments developed over time. A successional change of Lactobacillus communities was observed from birth, through creep feeding to one week after weaning, showing a trend from simple to complex and back to simple. Furthermore, a clone library of Lactobacillus spp. 16S rRNA gene sequences were generated from jejunal and colonic chymes. Six dominant DGGE bands generated from jejunal chymes were matched with sequences that show 94-98% similarity to the bands derived from L. reuteri, L. delbrueckii, and L. crispatus. Seven dominant DGGE bands generated from colon chymes were matched with sequences that show 88-99% similarity to those derived from L. reuteri, L. delbrueckii, L. amylovorus/L. sobrius, and L. acidophilus. Amplicons related to L. reuteri were found in all DGGE fingerprints from jejunal digesta of age of weeks 1, 3, and 4. Amplicons related to L. amylovorus/L. sobrius were present in all DGGE fingerprints from colonic digesta of age of week 1, 3, and 4. Amplicons related to L. delbrueckii were found before weaning, L. crispatus after creep feeding before weaning and L. acidophilus after weaning. This indicates that L. reuteri and L. amylovorus/L. sobrius probably belong to the permanent composition, while L. delbruckii, L. acidophilus, and L. crispatus probably belong to the temporal groups of Lactobacillus communities in the GI tract of piglets.
文摘Schistosomiasis is a public health concern in Benin. Freshwater snails of the genus Bulinus serve as intermediate hosts for schistosomes, trematode parasites responsible for bilharzia. The urinary form, caused by Schistosoma haematobium, is the most widespread and is transmitted to humans by these mollusks, with Bulinus truncatus and Bulinus globosus being the most important species. Effective strategies to combat the transmission of these parasites require a prior understanding of the molecular characterization of Bulinus snails. For this purpose, 293 Bulinus snails were collected and morphologically identified from two localities in southern Benin, Sô-Ava and Azowlissè. The snails were preserved in absolute alcohol. To achieve the set objectives, DNA was extracted from the collected biological material, and SSU gene fragments were amplified. Using PCR-RFLP, the amplified fragments were digested with the restriction endonucleases HaeIII, HinfI, and DdeI to perform molecular characterization. In this study, 80 individuals of B. globosus and 10 of B. truncatus were subjected to molecular analysis. The PCR-RFLP profiles showed bands of different sizes for the Bulinus species when analyzed with the three endonucleases using the SSU molecular marker. PCR-RFLP analysis revealed that the snails belonged to the freshwater genus Bulinus, including Bulinus globosus and B. truncatus, based on reference profiles from studies conducted in Nigeria, which enabled precise identification of these gastropods. This study provided initial insights, although still incomplete, into the molecular diversity of these species.
基金the Program for Science&Technology Innovation Talents in Universities of Henan Province(24HASTIT069)Postdoctoral Research Grant in Henan Province(HN2022041)+1 种基金Key Research Projects of Universities in Henan Province(24A150018)NMPA Key Laboratory for Research and Evaluation of Innovative Drug,Henan Key Laboratory of Organic Functional Molecules and Drug Innovation,and 111 Project(D17007)for financial support.
文摘Presented herein is a condition-controlled selective synthesis of CF_(3)-chromene and CF_(3)-benzofuran based on the reaction of N-phenoxyacetamide and CF_(3)-ynone.When the reaction is carried out in MeOH under the catalysis of Rh(III),CF_(3)-chromene is formed via C—H metalation-initiated alkenylation,acetamide group migration and intramolecular oxo-nucleophilic addition.On the other hand,when the reaction is run in DMSO under the promotion of CsOAc,CF_(3)-benzofuran is generated via aza-Michael addition-initiated[3,3]-σrearrangement,intramolecular oxo-nucleophilic addition and water elimination.To our knowledge,this is the first report on the selective construction of chromene or benzofuran scaffold along with introduction of a CF_(3) unit from the same starting materials.The methodology was scalable and the products could be readily transformed into other valuable products.Moreover,the products thus obtained possess decent anticancer activity.
文摘A direct and structurally divergent synthesis of indole alkaloids from very simple 2-vinylanilines, alkynes and TBN via a novel substrate flag- mentation/cycloaddition strategy has been developed, which provides an efficient noble-metal-free approach to access a library of highly valuable indole derivatives of tryptamines and tryptamine-related oximes, lactams, and lactones, as well as β-carbolines, spiroindolines, and hexa-hydropyrrolo[2,3-b]- indoles.
基金This paper is dedicated to Professor Youyou Tu,the 2015 Nobel Prize Laureate of Physiology or Medicine on the occasion of her 90th Birthday.This work was supported by the Program of National Natural Science Foundation of China(Nos.U1706210,41776141 and 41322037)the Fundamental Research Funds for the Central Universities(No.201841004)+1 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0403-2)the Taishan Scholars Program,China(No.tsqn20161010).
文摘Natural products derived from marine microorganisms have received great attention as a potential resource of new compound entities for drug discovery.The unique marine environment brings us a large group of sulfur-containing natural products with abundant biological functionality including antitumor,antibiotic,anti-inflammatory and antiviral activities.We reviewed all the 484 sulfur-containing natural products(non-sulfated)isolated from marine microorganisms,of which 59.9%are thioethers,29.8%are thiazole/thiazoline-containing compounds and 10.3%are sulfoxides,sulfones,thioesters and many others.A selection of 133 compounds was further discussed on their structure-activity relationships,mechanisms of action,biosynthesis,and druggability.This is the first systematic review on sulfur-containing natural products from marine microorganisms conducted from January 1987,when the first one was reported,to December 2020.
基金the National Natural Science Foundation of China(Nos.22171178,21871174 to B.X.)Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-09-E00008 to B.X.)for financial support+2 种基金The Sailing Program of Science and Technology Commission of Shanghai Municipality(22YF1413200 to M.G.)Young Talents Sailing Project(Shanghai University to M.G.)Shanghai Overseas Leading Talents Project(M.G.)are also appreciated.
文摘An unprecedented copper nitrate-mediated bond cleavage of alkynes was developed for the modular synthesis of isoxazoles,where either C—S bond or C≡C triple bond was cleaved selectively.Substituents attached to the C≡C triple bonds could differentiate the chemical bonds cleavage and reaction pathways disparately.Various transformations of products illustrate promising applications of the given protocols.
基金supported by the Swiss National Science Foundation grants No.31-59271.99 and No.3100AO-100762 to J.S.and a grant of the Freiwillige Akademische Gesellschaft to H.H.Æ.
文摘The effect of anthropogenic landscape fragmentation on the genetic diversity and adaptive potential of plant populations is a major issue in conservation biology.However,little is known about the partitioning of genetic diversity in alpine species,which occur in naturally fragmented habitats.Here,we investigate molecular patterns of three alpine plants(Epilobium fleischeri,Geum reptans and Campanula thyrsoides)across Switzerland and ask whether spatial isolation has led to high levels of population differentiation,increasing over distance,and a decrease of within-population variability.We further hypothesize that the contrasting potential for long-distance dispersal(LDD)of seed in these species will considerably influence and explain diversity partitioning.Methods For each study species,we sampled 20–23 individuals from each of 20–32 populations across entire Switzerland.We applied Random Amplified Polymorphic Dimorphism markers to assess genetic diversity within(Nei’s expected heterozygosity,He;percentage of polymorphic bands,Pp)and among(analysis of molecular variance,Ust)populations and correlated population size and altitude with within-population diversity.Spatial patterns of genetic relatedness were investigated using Mantel tests and standardized major axis regression as well as unweighted pair group method with arithmetic mean cluster analyses and Monmonier’s algorithm.To avoid known biases,we standardized the numbers of populations,individuals and markers using multiple random reductions.We modelled LDD with a high alpine wind data set using the terminal velocity and height of seed release as key parameters.Additionally,we assessed a number of important life-history traits and factors that potentially influence genetic diversity partitioning(e.g.breeding system,longevity and population size).Important findings For all three species,we found a significant isolation-by-distance relationship but only a moderately high differentiation among populations(Ust:22.7,14.8 and 16.8%,for E.fleischeri,G.reptans and C.thyrsoides,respectively).Within-population diversity(He:0.19–0.21,Pp:62–75%)was not reduced in comparison to known results from lowland species and even small populations with<50 reproductive individuals contained high levels of genetic diversity.We further found no indication that a high long-distance seed dispersal potential enhances genetic connectivity among populations.Gene flow seems to have a strong stochastic component causing large dissimilarity between population pairs irrespective of the spatial distance.Our results suggest that other life-history traits,especially the breeding system,may play an important role in genetic diversity partitioning.We conclude that spatial isolation in the alpine environment has a strong influence on population relatedness but that a number of factors can considerably influence the strength of this relationship.
基金National Natural Science Foundation of China(No.22101133)Natural Science Foundation of Jiangsu Province(No.BK20200768)and Nanjing Forestry University are greatly acknowledged.
文摘An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C_(3)-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromophenyl)acrylamides and organoboron reagents was successfully developed by using a 1,3-bis(2,6-diisopropylphenyl)acenaphthoimidazol-2-ylidene(AnIPr)-ligated oxazoline palladacycle.It enabled a very broad substrate scope tolerating different functional groups,electronic properties and steric bulkiness.Notably,it revealed a great potential to build diverse heterocycle-fused indoline alkaloids via the same intermediate 3-allyl-1,3-dimethylindolin-2-one.
