Project description:The root of Gentiana straminea Maxim. (Gentianaceae), is officially listed as "Qin-Jiao" in the Chinese Pharmacopoeia for the treatment of rheumatic arthritis, icteric hepatitis, constipation, pain, and hypertension. To establish the geographical origin traceability in G. straminea, its chemical profiles were determined by a UPLC-Q exactive mass spectrometer, from which 43 compounds were identified by comparing retention times and mass spectrometry. Meanwhile, a pair of isomers (loganin and secologanol) was identified by mass spectrometry based on their fragmentation pathway. A total of 42 samples from difference habitats were determined by an UPLC-Q exactive mass spectrometer and the data were assayed with multivariate statistical analysis. Eight characteristic compounds were identified to determine the geographical origin of the herb. To estimate the key characteristic markers associated with pharmacological function, the inhibiting activities of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced macrophages were examined. This finding is crucial in realizing the determination of botanical origin and evaluating the quality of G. straminea.
Project description:Paralogous members of the oxidosqualene cyclase (OSC) family encode a diversity of enzymes that are important in triterpenoid biosynthesis. This report describes the isolation of the Gentiana straminea gene GsAS2 that encodes a ?-amyrin synthase (?AS) enzyme. Unlike its previously isolated paralog GsAS1, GsAS2 lacks introns. Its predicted protein product was is a 759 residue polypeptide that shares high homology with other known ?-amyrin synthases (?ASs). Heterologously expressed GsAS2 generates more ?-amyrin in yeast than does GsAS1. Constitutive over-expression of GsAS2 resulted in a 5.7 fold increase in oleanolic acid accumulation, while over-expression of GsAS1 led to a 3 fold increase. Additionally, RNAi-directed suppression of GsAS2 and GsAS1 in G. straminea decreased oleonolic acid levels by 65.9% and 21% respectively, indicating that GsAS2 plays a more important role than GsAS1 in oleanolic acid biosynthesis in G. straminea. We uses a docking model to explore the catalytic mechanism of GsAS1/2 and predicted that GsAS2, with its Y560, have higher efficiency than GsAS1 and mutated versions of GsAS2 in ?-amyrin produce. When the key residue in GsAS2 was mutagenized, it produced about 41.29% and 71.15% less ?-amyrin than native, while the key residue in GsAS1 was mutagenized to that in GsAS2, the mutant produced 38.02% more ?-amyrin than native GsAS1.
Project description:DNA barcoding of plants poses particular challenges, especially in differentiating, recently diverged taxa. The genus Gentiana (Gentianaceae) is a species-rich plant group which rapidly radiated in the Himalaya-Hengduan Mountains in China. In this study, we tested the core plant barcode (rbcL + matK) and three promising complementary barcodes (trnH-psbA, ITS and ITS2) in 30 Gentiana species across 6 sections using three methods (the genetic distance-based method, Best Close Match and tree-based method). rbcL had the highest PCR efficiency and sequencing success (100%), while the lowest sequence recoverability was from ITS (68.35%). The presence of indels and inversions in trnH-psbA in Gentiana led to difficulties in sequence alignment. When using a single region for analysis, ITS exhibited the highest discriminatory power (60%-74.42%). Of the combinations, matK + ITS provided the highest discrimination success (71.43%-88.24%) and is recommended as the DNA barcode for the genus Gentiana. DNA barcoding proved effective in assigning most species to sections, though it performed poorly in some closely related species in sect. Cruciata because of hybridization events. Our analysis suggests that the status of G. pseudosquarrosa needs to be studied further. The utility of DNA barcoding was also verified in authenticating 'Qin-Jiao' Gentiana medicinal plants (G. macrophylla, G. crassicaulis, G. straminea, and G. dahurica), which can help ensure safe and correct usage of these well-known Chinese traditional medicinal herbs.
Project description:Schistosomiasis, also generally known as snail fever, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. In Hong Kong and mainland China, the freshwater snail Biomphalaria straminea has been introduced and has the potential to transmit intestinal schistosomiasis caused by S. mansoni, a parasite of man which has a wide distribution in Africa and parts of the New World, especially Brazil. The first identification of B. straminea in Hong Kong dates back to the 1970s, and its geographical distribution, phylogenetic relationships, and infection status have not been updated for more than 30 years. Thus, this study aims to reveal the distribution and current infection status of B. straminea in contemporary Hong Kong.Snails were collected from different parts of Hong Kong from July 2016 to January 2017. Both anatomical and molecular methods were applied to identify B. straminea. Cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 1 (ITS1), 5.8S rDNA, internal transcribed spacer 2 (ITS2), and 16S ribosomal DNA (rDNA) were sequenced from individual snails and analyzed. To detect the presence of S. mansoni, both biopsy and PCR analyses were carried out.Using both anatomical and molecular analyses, this study demonstrated the existence of black- and red-coloured shell B. straminea in different districts in the New Territories in Hong Kong, including places close to the mainland China border. None of the B. straminea (n = 87) investigated were found to be infected with S. mansoni when tested by biopsy and PCR. The Hong Kong B. straminea are genetically indistinguishable, based on the chosen molecular markers (cox1, ITS1-5.8S-ITS2, and 16S rDNA), and are similar to those obtained in mainland China and South America.Biomphalaria straminea is now well established in freshwater habitats in Hong Kong. No evidence of infection with S. mansoni has been found. Surveillance should be continued to monitor and better understand this schistosomiasis intermediate host in mainland China and Hong Kong.
Project description:BACKGROUND:The chloroplast (cp) genome is useful in plant systematics, genetic diversity analysis, molecular identification and divergence dating. The genus Gentiana contains 362 species, but there are only two valuable complete cp genomes. The purpose of this study is to report the characterization of complete cp genome of G. lawrencei var. farreri, which is endemic to the Qinghai-Tibetan Plateau (QTP). METHODS:Using high throughput sequencing technology, we got the complete nucleotide sequence of the G. lawrencei var. farreri cp genome. The comparison analysis including genome difference and gene divergence was performed with its congeneric species G. straminea. The simple sequence repeats (SSRs) and phylogenetics were studied as well. RESULTS:The cp genome of G. lawrencei var. farreri is a circular molecule of 138,750 bp, containing a pair of 24,653 bp inverted repeats which are separated by small and large single-copy regions of 11,365 and 78,082 bp, respectively. The cp genome contains 130 known genes, including 85 protein coding genes (PCGs), eight ribosomal RNA genes and 37 tRNA genes. Comparative analyses indicated that G. lawrencei var. farreri is 10,241 bp shorter than its congeneric species G. straminea. Four large gaps were detected that are responsible for 85% of the total sequence loss. Further detailed analyses revealed that 10 PCGs were included in the four gaps that encode nine NADH dehydrogenase subunits. The cp gene content, order and orientation are similar to those of its congeneric species, but with some variation among the PCGs. Three genes, ndhB, ndhF and clpP, have high nonsynonymous to synonymous values. There are 34 SSRs in the G. lawrencei var. farreri cp genome, of which 25 are mononucleotide repeats: no dinucleotide repeats were detected. Comparison with the G. straminea cp genome indicated that five SSRs have length polymorphisms and 23 SSRs are species-specific. The phylogenetic analysis of 48 PCGs from 12 Gentianales taxa cp genomes clearly identified three clades, which indicated the potential of cp genomes in phylogenetics. DISCUSSION:The "missing" sequence of G. lawrencei var. farreri mainly consistent of ndh genes which could be dispensable under chilling-stressed conditions in the QTP. The complete cp genome sequence of G. lawrencei var. farreri provides intragenic information that will contribute to genetic and phylogenetic research in the Gentianaceae.
Project description:BACKGROUND:Biomphalaria straminea is an invasive vector in China, posing a significant threat to public health. Understanding the factors affecting the establishment of this snail is crucial to improve our ability to manage its dispersal and potential risk of schistosomiasis transmission. This study sought to determine the spatial distribution of B. straminea in mainland China and whether environmental factors were divergent between places with and without B. straminea. METHODS:A malacological survey of B. straminea was conducted in Guangdong Province, China. Snails were identified using anatomical keys. Water and sediment samples were taken, and their physicochemical properties were analyzed using national standard methods. Landscape and climatic variables were also collected for each site. We compared the environmental characteristics between sites with and without B. straminea using Mann-Whitney U test. We further used generalized linear mixed models to account for seasonal effects. RESULTS:B. straminea was found at six sites, including one in Dongguan and five in Shenzhen. Probability map found a hot spot of B. straminea distribution at Shenzhen and Hong Kong. Sites occupied by B. straminea were characterized by higher median altitude, mean annual precipitation and moderate temperature. Water with snails had higher median concentrations of total nitrogen, nitrate and nitrites, ammoniacal nitrogen, calcium, zinc and manganese but lower dissolved oxygen and magnesium. Sediments with snails had higher median copper, zinc and manganese. B. straminea was associated with maximum temperature of the warmest month (pMCMC <?0.001) and sediment zinc (pMCMC <?0.001). CONCLUSIONS:B. straminea is distributed in Shenzhen and its surrounding areas in Guangdong, China. Sites with and without B. straminea differed in the maximum temperature of the warmest month and sediment zinc. Surveillance should be continued to monitor the dispersal of this snail in China.
Project description:Schistosomiasis is a snail-borne parasitic disease and is endemic in many tropical and subtropical countries. Biomphalaria straminea, an intermediate host for Schistosoma mansoni, is native to the southeastern part of South America and has established in other regions of South America, Central America and southern China during the last decades. S. mansoni is endemic in Africa, the Middle East, South America and the Caribbean. Knowledge of the potential global distribution of this snail is essential for risk assessment, monitoring, disease prevention and control.A comprehensive database of cross-continental occurrence for B. straminea was compiled to construct ecological models. We used several approaches to investigate the distribution of B. straminea, including direct comparison of climatic conditions, principal component analysis and niche overlap analyses to detect niche shifts. We also investigated the impacts of bioclimatic and human factors, and then used the bioclimatic and footprint layers to predict the potential distribution of B. straminea at global scale. We detected niche shifts accompanying the invasions of B. straminea in the Americas and China. The introduced populations had enlarged its habitats to subtropical regions where annual mean temperature is relatively low. Annual mean temperature, isothermality and temperature seasonality were identified as most important climatic features for the occurrence of B. straminea. Additionally, human factors improved the model prediction (P<0.001). Our model showed that under current climate conditions the snail should mostly be confined to the tropic and subtropic regions, including South America, Central America, Sub-Saharan Africa and Southeast Asia.Our results confirmed that niche shifts took place in the invasions of B. straminea, in which bioclimatic and human factors played an important role. Our model predicted the global distribution of B. straminea based on habitat suitability, which would help for prioritizing monitoring and management efforts for B. straminea control in the context of ongoing climate change and human disturbances.
Project description:BACKGROUND:Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization. Schistosomiasis mansoni is a form of the disease that is caused by the digenean trematode Schistosoma mansoni, transmitted through Biomphalaria spp. as an intermediate host. Biomphalaria was introduced to Hong Kong, China in aquatic plants shipments coming from Brazil and the snail rapidly established its habitats in southern China. Earlier studies of Biomphalaria spp. introduced to southern China identified the snails as Biomphalaria straminea, one of the susceptible species implicated in S. mansoni transmission in South America. However, recent molecular investigations also indicated the presence of another South American species, B. kuhniana, which is refractory to infection. As such, it is important to identify accurately the species currently distributed in southern China, especially with emerging reports of active S. mansoni infections in Chinese workers returning from Africa. METHODS:We combined morphological and molecular taxonomy tools to precisely identify Biomphalaria spp. distributed in Guangdong Province, southern China. In order to clearly understand the molecular profile of the species, we constructed a phylogeny using mtDNA data (COI and 16S rRNA sequences) from six populations of Biomphalaria spp. from Shenzhen City in Guangdong Province. In addition, we examined the external morphology of the shell and internal anatomy of the reproductive organs. RESULTS:Both morphological and molecular evidences indicated a close affinity between Biomphalaria spp. populations from Guangdong and B. straminea from Brazil. The shell morphology was roughly identical in all the populations collected with rounded whorls on one side and subangulated on the other, a smooth periphery, an egg-shaped aperture bowed to one side, and a deep umbilicus. The shape and number of prostate diverticula (ranged from 11.67 to 17.67) in Guangdong populations supports its close affinity to B. straminea rather than B. kuhniana. Molecular analysis did not conflict with morphological analysis. Little genetic differentiation was observed within Biomphalaria populations collected. Phylogenetic analysis of COI and 16S rRNA haplotypes from snails collected and B. straminea sequences from Brazil and China using Bayesian inference revealed that Guangdong populations were clustered in one clade with B. straminea from Hong Kong of China and B. straminea from Brazil indicating their close affinity to each other. CONCLUSIONS:Data obtained in the current study clearly show that the populations of Biomphalaria spp. investigated are B. straminea, and we assume that those snails were either introduced via passive dispersal from Hong Kong of China or as a result of multiple introduction routes from Brazil.