Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemi...Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.展开更多
Background:Geographical distribution of endemic species and its multiple scale drivers are an important topic in biodiversity conservation,because these species are especially vulnerable to climate change and habitat ...Background:Geographical distribution of endemic species and its multiple scale drivers are an important topic in biodiversity conservation,because these species are especially vulnerable to climate change and habitat degradation,and therefore have high conservation priority.Here,for the first time,we simultaneously linked glacial-interglacial climate change,contemporary climate,plant species richness and altitudinal range with endemic bird distribution in China.Methods:Ordinary least squares models and simultaneous autoregressive models were used to assess the associations between endemic bird richness,endemic bird ratio and each explanatory variable.Structural Equation Models were also performed to test the direct and indirect effects of these variables on endemic bird richness and endemic bird ratio.Results:Higher endemic bird richness and endemic bird ratio occurred in regions with stable glacial-interglacial temperature,i.e.,southwest China.Plant species richness and altitudinal range were also positively correlated with endemic bird richness and endemic bird ratio.Glacial-interglacial temperature change,contemporary precipitation,plant species richness and altitudinal range were all included in the best combination of variables for endemic bird richness.Importantly,glacial-interglacial temperature change had strong direct effects on both endemic bird richness and endemic bird ratio,while plant species richness only had a direct effect on endemic bird richness.Conclusions:Our results indicate that endemic birds in China concentrate in southwest regions where there are stable glacial-interglacial temperature,more plant species and larger altitudinal range.Notably,while stable climate has strong direct effects on both endemic bird richness and endemic bird ratio,plant species may affect endemic bird richness through its effect on overall bird species richness.Importantly,the recent anthropogenic activities have also significantly intensified in this region,which would pose huge challenge for biodiversity conservation in China.展开更多
We review the fossil history of seed plant genera that are now endemic to eastern Asia. Although the majority of eastern Asian endemic genera have no known fossil record at all, 54 genera, or about 9%, are reliably kn...We review the fossil history of seed plant genera that are now endemic to eastern Asia. Although the majority of eastern Asian endemic genera have no known fossil record at all, 54 genera, or about 9%, are reliably known from the fossil record. Most of these are woody （with two exceptions）, and most are today either broadly East Asian, or more specifically confined to Sino-Japanese subcategory rather than being endemic to the Sino-Himalayan area. Of the ＂eastern Asian endemic＂ genera so far known from the fossil record, the majority formerly occurred in Europe and/or North America, indicating that eastern Asia served as a late Tertiary or Quaternary refugium for taxa. Hence, many of these genera may have originated in other parts of the Northern Hemisphere and expanded their ranges across continents and former sea barriers when tectonic and climatic conditions allowed, leading to their arrival in eastern Asia. Although clear evidence for paleoendemism is provided by the gymnosperms Amentotaxus, Cathaya, Cephalotaxus, Cunninghamia, Cryptomeria, Glyptostrobus, Ginkgo, Keteleeria, Metasequoia, Nothotsuga, Pseudolarix, Sciadopitys, and Taiwania, and the angiosperms Cercidiphyllum, Choerospondias, Corylopsis, Craigia, Cyclocarya, Davidia, Dipelta, Decaisnea, Diplopanax, Dipteronia, Emmenopterys, Eucommia, Euscaphis, Hemiptelea, Hovenia, Koelreuteria, Paulownia, Phellodendron, Platycarya, Pteroceltis, Rehderodendron, Sargentodoxa, Schizophragma, Sinomenium, Tapiscia, Tetracentron, Toricellia, Trapella, and Trochodendron, we cannot rule out the possibility that neoendemism plays an important role especially for herbaceous taxa in the present-day flora of Asia, particularly in the Sino-Himalayan region. In addition to reviewing paleobotanical occurrences from the literature, we document newly recognized fossil occurrences that expand the geographic and stratigraphic ranges previously known for Dipelta, Pteroceltis, and Toricellia.展开更多
Amphibians are good indicators of ecosystem health. Updating the information of endemic species in time and understanding their spatial distributions are necessary for the development of integrative conservation strat...Amphibians are good indicators of ecosystem health. Updating the information of endemic species in time and understanding their spatial distributions are necessary for the development of integrative conservation strategies and the elucidation of geographic patterns of amphibians. We analyzed the diversity and distributions of the endemic amphibians in China based on a database of specimen records, recently published literature, and field surveys. Two hundred and sixty two endemic species of amphibians, belonging to 59 genera in 12 families and two orders, are recognized. They account for 67% of the total number of amphibian species in China, with the family Megophryidae possessing the largest number of endemics. There are also 17 genera endemic to China. Across provinces, the species richness of endemics shows five levels with a hierarchical diversification. Sichuan has the largest number of endemics, while Heilongjiang and Jilin have no endemic species. Alternatively, whether on the level of endemic genus or species, the highest diversity occurs in the Western Mountains and Plateau Subregion. The distribution ranges of most endemic species cover ≤ 4 provinces or zoogeographic subregions. Additionally, the species richness of endemics along an elevational gradient shows a bell-shaped pattern with the peak around 800 m. Most endemic species are distributed in areas of low to mid elevation(c. 700–1 500 m), while 36 species are distributed up to 3 000 m. Endemic species richness decreases with increasing of elevation range. Species at mid elevations display large range sizes, while species at lower and higher elevations exhibit smaller ranges. Our results are to be beneficial for further exploration of the underlying mechanisms of distributional patterns of amphibians in China. This study highlights a need to promote conservation programs for Chinese endemic amphibians due to their narrow distribution ranges and potential threats.展开更多
Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dorman...Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.展开更多
Many cases of an unknown disease exhibiting the clinical features of limb gangrene,blisters,ulceration,and exfoliation have been reported in Daping village(DV)in southwestern China.However,the pathogenesis is unknown ...Many cases of an unknown disease exhibiting the clinical features of limb gangrene,blisters,ulceration,and exfoliation have been reported in Daping village(DV)in southwestern China.However,the pathogenesis is unknown and has puzzled doctors for many years.A preliminary study on heavy metals and symptoms indicated that arsenic might pose the greatest threat to the health of local residents.Here,to explore the sources of and factors influencing arsenic enrichment in DV,whose residents exhibit signs of arsenic poisoning,the As contents in soil,water,and plants were systematically measured.The results indicated high As contents in plant and soil samples obtained from the area,and the source of As may be linked to the weathering of black shale rock.Ingestion of soil and consumption of plants were the two main As exposure pathways among children and adults,respectively,and children exhibited a higher health risk than adults.We presume and emphasize that when extreme drought events occur,humans might face unusual risks resulting from exposure to toxic elements and the direct consumption of highly polluted water.Our study provides a new perspective and sheds light on the environmental geochemistry and health links of this disease.展开更多
Endemic plants are important for understanding phylogenetic relationships,biogeographical history,and genetic variation because of their restricted distribution and their role in conserving biodiversity.Here,we invest...Endemic plants are important for understanding phylogenetic relationships,biogeographical history,and genetic variation because of their restricted distribution and their role in conserving biodiversity.Here,we investigated the phylogenetic relationships of the Korean endemic Fraxinus chiisanensis by reconstructing the molecular phylogeny of Fraxinus based on two nuclear DNA(nrITS and phantastica)and two chloroplast DNA(psbA-trnH and rp132-trnL)regions.Within our fossil-calibrated phylogenetic framework,we also inferred the biogeographical history of F.chiisanensis.To provide a scientific basis for the conservation of F.chiisanensis,we determined the levels of genetic diversity and genetic differentiation in this species.Combining information from nuclear and chloroplast DNA sequence data,our molecular phylogenetic analyses identified F.chiisanensis as a genetically distinct unit from its sister group,Fraxinus platypoda from Japan.Our molecular dating analyses using nuclear and chloroplast DNA data sets show F.chiisanensis diverged from its sister F.platypoda in the Early or Middle Miocene and differentiated in the Late Miocene on the Korean Peninsula.Our results suggest that the divergence of F.chiisanensis was associated with the submergence of the East China Sea land bridge and enhanced monsoons in East Asia.When compared to F.platypoda,F.chiisanensis exhibits low genetic diversity within populations and high genetic differentiation among populations.These results help us to understand the evolutionary history of F.chiisanensis and to develop a conservation strategy for this species.展开更多
With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combin...With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combined data on the distribution of 1010 stenochoric endemic seed plants,vegetation constitution,geological history and climate change,and used these to propose a new system of floristic regions.We identified 11 distinct floristic subregions and 84 floristic provinces within Yunnan.Our work confirmed some views emphasized by Wu Zhengyi that the stenochoric endemic species play a key role in defining floristic provinces;that stenochoric endemic plants with long collection and publication histories are more valuable;that greater attention should be paid to woody plants;and that for Yunnan,a border region,some trans-border distributed elements should be treated cautiously.展开更多
This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone acros...This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone across China ranging from North-East to South-West. Selenium contents in food grains and human hair from the disease affected areas are usually below 0.020ppm and 0.20ppm respectively. The endemic goitre caused by iodine deficiency distributes extensively in China, mainly in mountainous and hilly districts, swamp and peat areas, some sand soil and limestone areas. Also there is another kind of endemic goitre which caused by iodine excess in interior and coast areas. Endemic cretinism usually occurs in the endemic goitre seriously affected areas. Endemic fluorosis is also widely distributed in China, but mainly occurs in dry or semi-dry areas of north China. The fluoride sources for causing endemic fluorisis are drinking water and food grains polluted by coal smoke in the backing process of maize and chilli.展开更多
Background: China has a relative high degree of endemism of birds due to its large area, diversified topography, and varied climates and habitats. Among the 77 Chinese endemic birds, 29 species are classified as threa...Background: China has a relative high degree of endemism of birds due to its large area, diversified topography, and varied climates and habitats. Among the 77 Chinese endemic birds, 29 species are classified as threatened according to the officially released China Biodiversity Red List in 2015. Chinese endemic birds should be the focus of conservation because their local extinction in China means complete global extinction. However, to date, no study has explicitly examined the patterns and processes of extinction and threat in Chinese endemic birds. Methods: We obtained eleven biological traits and four extrinsic factors that are commonly hypothesized to influence extinction risk. After phylogenetic correction, these factors were used separately and in combination to assess their associations with extinction risk. Results: We found that 37.7% of Chinese endemic birds were listed as threatened (Vulnerable, Endangered and Critically Endangered). Small range size, high hunting vulnerability, and high human population density were important predictors of high extinction risk in Chinese endemic birds. Conclusions: Our study is the first to systematically investigate the patterns and processes of extinction risk in Chinese endemic birds. We suggest that endemic species with small range size and living in area with high human densities require conservation priorities. Conservation efforts should also focus on the reduction of human threats, such as human hunting and habitat degradation, for the effective preservation of Chinese endemic birds.展开更多
Objective:To predict the factors associated with progression to severe dengue infection to prevent potentially fatal complications and to identify the determinants of severe complicated dengue.Methods:The study was co...Objective:To predict the factors associated with progression to severe dengue infection to prevent potentially fatal complications and to identify the determinants of severe complicated dengue.Methods:The study was conducted in a tertiary care hospitaldengue ward from September to November 2021 including confirmed dengue infected patients(positive NS1 antigen or antidengue-antibodies IgM).Secondary dengue infection was labelled by positive anti-dengue-antibodies IgG in active dengue infected patients.Detailed history,physical examination,laboratory and radiological parameters,hospital stay(days)and mortality percentages were noted.Patients were classified into three groups according to disease severity:dengue fever(DF),dengue hemorrhagic fever(DHF)and dengue shock syndrome(DSS).The predictors of complicated dengue infection were determined by regression analysis.Results:The most common symptom was fever(96.9%).Among 129 patients,62.8%had DF,31.0%had DHF and only 6.2%developed DSS.History of previous symptomatic dengue and positive anti-dengue-antibodies IgG were present in 100%DSS patients and nearly 75.0%DHF patients(P<0.05).The moratlity rate in patients with DSS,DHF and DF was 50.0%,2.5%and none respectively(P<0.05).Clinical parameters(body aches,bleeding,conjunctival hemorrhage,maculopapular rash,right hypochondrial tenderness,ascites,pleural effusion)and laboratory parameters(thrombocytopenia,raised alanine aminotransferase and secondary dengue infection)were determinants that complicate the dengue infection.Conclusions:Thrombocytopenia,raised alanine aminotransferase and secondary dengue infection are important laboratory parameters to complicate the disease process of dengue infection.展开更多
The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other h...The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other hand, an intake of 40 μg/d is required to maintain the plasma glutathione peroxidase (GPx) activity at plateau. Hence 40 μg/d is considered as the adequate dietary selenium requirement. Studies conducted in a chronic selenosis area indicate thai the toxic dietary selenlum inlake (adverse effect level), which would maintain the characteristic fingernail changes, was approximately 1600 μg/d. The mean value of dietary selenium intakes, which enabled the five patients to recover from fingernail lesions, was found to be 819 ±126μg/d. At a 95% confidence limit, the lower limit is around 600μg/d. Therefore, 600 and 400μg/d were suggested as the individual daily maximum safe selenium intake and the safe dietary selenium intake, respectively,The results were used in the prevention of Se-related endemic KD and Kashin-Beck disease (KBD)展开更多
Dengue is one of the most common arthropod-borne viral diseases in humans and it is a leading cause of illness and death in the tropical and subtropical regions of the world. It is thought to account for 400 million c...Dengue is one of the most common arthropod-borne viral diseases in humans and it is a leading cause of illness and death in the tropical and subtropical regions of the world. It is thought to account for 400 million cases annually among approximately 3.97 billion people at risk of infection in 128 endemic countries. Despite the global prevalence of the disease, the availability of a vaccine is limited in most countries in the endemic areas. Most endemic countries in South America, South East Asia and Africa serve as attractive touristic sites for people from non-endemic countries who become infected and export the virus to dengue-free regions. Dengue fever typically resembles malaria and in endemic countries most cases of dengue are treated as presumptive malaria. Consequently, routine dengue diagnosis among persons with fever will offer early treatment and reduce the burden of the disease. Also, routine testing among travellers from endemic countries will reduce importation and prevent the geographical expansion of dengue. In this essay, we seek to highlight the usefulness of routine dengue testing in endemic countries.展开更多
Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species.In this study,the spatial distribution of five endemic and threatened spec...Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species.In this study,the spatial distribution of five endemic and threatened species belonging to the genus Onosma(including O.asperrima,O.bisotunensis,O.kotschyi,O.platyphylla,and O.straussii)was investigated under present and future climate change scenarios:RCP2.6(RCP,representative concentration pathway;optimistic scenario)and RCP8.5(pessimistic scenario)for the years 2050 and 2080 in Iran.Analysis was conducted using the maximum entropy(MaxEnt)model to provide a basis for the protection and conservation of these species.Seven environmental variables including aspect,depth of soil,silt content,slope,annual precipitation,minimum temperature of the coldest month,and annual temperature range were used as main predictors in this study.The model output for the potential habitat suitability of the studied species showed acceptable performance for all species(i.e.,the area under the curve(AUC)>0.800).According to the models generated by MaxEnt,the potential current patterns of the species were consistent with the observed areas of distributions.The projected climate maps under optimistic and pessimistic scenarios(RCP2.6 and RCP8.5,respectively)of 2050 and 2080 resulted in reductions and expansions as well as positive range changes for all species in comparison to their current predicted distributions.Among all species,O.bisotunensis showed the most significant and highest increase under the pessimistic scenario of 2050 and 2080.Finally,the results of this study revealed that the studied plant species have shown an acute adaptability to environmental changes.The results can provide useful information to managers to apply appropriate strategies for the management and conservation of these valuable Iranian medicinal and threatened plant species in the future.展开更多
基金the“Metropolitan Mosquitoes Project”funded by the Swedish Research Council for Environment,Agricultural Sciences and Spatial Planning(Formas,grant number 2016-00364).
文摘Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.
基金supported by the National Natural Science Foundation of China(No.41861004 granted to GF,and 31870506 to ML)the Inner Mongolia Grassland Talent(12000-12102228 to GF)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB31000000 granted to ML)Natural Science Foundation of Jiangsu Province(BK20181398 granted to ML)。
文摘Background:Geographical distribution of endemic species and its multiple scale drivers are an important topic in biodiversity conservation,because these species are especially vulnerable to climate change and habitat degradation,and therefore have high conservation priority.Here,for the first time,we simultaneously linked glacial-interglacial climate change,contemporary climate,plant species richness and altitudinal range with endemic bird distribution in China.Methods:Ordinary least squares models and simultaneous autoregressive models were used to assess the associations between endemic bird richness,endemic bird ratio and each explanatory variable.Structural Equation Models were also performed to test the direct and indirect effects of these variables on endemic bird richness and endemic bird ratio.Results:Higher endemic bird richness and endemic bird ratio occurred in regions with stable glacial-interglacial temperature,i.e.,southwest China.Plant species richness and altitudinal range were also positively correlated with endemic bird richness and endemic bird ratio.Glacial-interglacial temperature change,contemporary precipitation,plant species richness and altitudinal range were all included in the best combination of variables for endemic bird richness.Importantly,glacial-interglacial temperature change had strong direct effects on both endemic bird richness and endemic bird ratio,while plant species richness only had a direct effect on endemic bird richness.Conclusions:Our results indicate that endemic birds in China concentrate in southwest regions where there are stable glacial-interglacial temperature,more plant species and larger altitudinal range.Notably,while stable climate has strong direct effects on both endemic bird richness and endemic bird ratio,plant species may affect endemic bird richness through its effect on overall bird species richness.Importantly,the recent anthropogenic activities have also significantly intensified in this region,which would pose huge challenge for biodiversity conservation in China.
基金supported in part by US National Science Foundation grants EAR 9220079,0174295INT 0074295 to SRM+4 种基金National Basic Research Program of China (973 Program No.2007CB411600)Chinese Academy of Sciences (KSCX2-YW-R-136) to CZDin part by Research Project of the National Museum of Nature of Science (20077005)the Monbusho Grant-in-Aid for Scientific Research (17540446) for KUsupported through SRM's participation in the NSF (NESCent)-sponsored Phytogeography of the Northern Hemisphere Working Group
文摘We review the fossil history of seed plant genera that are now endemic to eastern Asia. Although the majority of eastern Asian endemic genera have no known fossil record at all, 54 genera, or about 9%, are reliably known from the fossil record. Most of these are woody （with two exceptions）, and most are today either broadly East Asian, or more specifically confined to Sino-Japanese subcategory rather than being endemic to the Sino-Himalayan area. Of the ＂eastern Asian endemic＂ genera so far known from the fossil record, the majority formerly occurred in Europe and/or North America, indicating that eastern Asia served as a late Tertiary or Quaternary refugium for taxa. Hence, many of these genera may have originated in other parts of the Northern Hemisphere and expanded their ranges across continents and former sea barriers when tectonic and climatic conditions allowed, leading to their arrival in eastern Asia. Although clear evidence for paleoendemism is provided by the gymnosperms Amentotaxus, Cathaya, Cephalotaxus, Cunninghamia, Cryptomeria, Glyptostrobus, Ginkgo, Keteleeria, Metasequoia, Nothotsuga, Pseudolarix, Sciadopitys, and Taiwania, and the angiosperms Cercidiphyllum, Choerospondias, Corylopsis, Craigia, Cyclocarya, Davidia, Dipelta, Decaisnea, Diplopanax, Dipteronia, Emmenopterys, Eucommia, Euscaphis, Hemiptelea, Hovenia, Koelreuteria, Paulownia, Phellodendron, Platycarya, Pteroceltis, Rehderodendron, Sargentodoxa, Schizophragma, Sinomenium, Tapiscia, Tetracentron, Toricellia, Trapella, and Trochodendron, we cannot rule out the possibility that neoendemism plays an important role especially for herbaceous taxa in the present-day flora of Asia, particularly in the Sino-Himalayan region. In addition to reviewing paleobotanical occurrences from the literature, we document newly recognized fossil occurrences that expand the geographic and stratigraphic ranges previously known for Dipelta, Pteroceltis, and Toricellia.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Y1B302100)to Junhua HUthe National Natural Science Foundation of China(NSFC,31071906)the Main Direction Program of the Knowledge Innovation Project of CAS(Grant No.KSCX2-EW-J-22)to Jianping JIANG
文摘Amphibians are good indicators of ecosystem health. Updating the information of endemic species in time and understanding their spatial distributions are necessary for the development of integrative conservation strategies and the elucidation of geographic patterns of amphibians. We analyzed the diversity and distributions of the endemic amphibians in China based on a database of specimen records, recently published literature, and field surveys. Two hundred and sixty two endemic species of amphibians, belonging to 59 genera in 12 families and two orders, are recognized. They account for 67% of the total number of amphibian species in China, with the family Megophryidae possessing the largest number of endemics. There are also 17 genera endemic to China. Across provinces, the species richness of endemics shows five levels with a hierarchical diversification. Sichuan has the largest number of endemics, while Heilongjiang and Jilin have no endemic species. Alternatively, whether on the level of endemic genus or species, the highest diversity occurs in the Western Mountains and Plateau Subregion. The distribution ranges of most endemic species cover ≤ 4 provinces or zoogeographic subregions. Additionally, the species richness of endemics along an elevational gradient shows a bell-shaped pattern with the peak around 800 m. Most endemic species are distributed in areas of low to mid elevation(c. 700–1 500 m), while 36 species are distributed up to 3 000 m. Endemic species richness decreases with increasing of elevation range. Species at mid elevations display large range sizes, while species at lower and higher elevations exhibit smaller ranges. Our results are to be beneficial for further exploration of the underlying mechanisms of distributional patterns of amphibians in China. This study highlights a need to promote conservation programs for Chinese endemic amphibians due to their narrow distribution ranges and potential threats.
文摘Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.
基金supported by the National Natural Science Foundation of China(Nos.41820104008 and U2202207)the Special Project for Social Development of Yunnan Province(No.202103AC100001)。
文摘Many cases of an unknown disease exhibiting the clinical features of limb gangrene,blisters,ulceration,and exfoliation have been reported in Daping village(DV)in southwestern China.However,the pathogenesis is unknown and has puzzled doctors for many years.A preliminary study on heavy metals and symptoms indicated that arsenic might pose the greatest threat to the health of local residents.Here,to explore the sources of and factors influencing arsenic enrichment in DV,whose residents exhibit signs of arsenic poisoning,the As contents in soil,water,and plants were systematically measured.The results indicated high As contents in plant and soil samples obtained from the area,and the source of As may be linked to the weathering of black shale rock.Ingestion of soil and consumption of plants were the two main As exposure pathways among children and adults,respectively,and children exhibited a higher health risk than adults.We presume and emphasize that when extreme drought events occur,humans might face unusual risks resulting from exposure to toxic elements and the direct consumption of highly polluted water.Our study provides a new perspective and sheds light on the environmental geochemistry and health links of this disease.
基金grants from the Korea National Arboretum(Grant no.KNA1-1-13,14-1)Gachon University(Grant no.2018-0320)to J-H Kim。
文摘Endemic plants are important for understanding phylogenetic relationships,biogeographical history,and genetic variation because of their restricted distribution and their role in conserving biodiversity.Here,we investigated the phylogenetic relationships of the Korean endemic Fraxinus chiisanensis by reconstructing the molecular phylogeny of Fraxinus based on two nuclear DNA(nrITS and phantastica)and two chloroplast DNA(psbA-trnH and rp132-trnL)regions.Within our fossil-calibrated phylogenetic framework,we also inferred the biogeographical history of F.chiisanensis.To provide a scientific basis for the conservation of F.chiisanensis,we determined the levels of genetic diversity and genetic differentiation in this species.Combining information from nuclear and chloroplast DNA sequence data,our molecular phylogenetic analyses identified F.chiisanensis as a genetically distinct unit from its sister group,Fraxinus platypoda from Japan.Our molecular dating analyses using nuclear and chloroplast DNA data sets show F.chiisanensis diverged from its sister F.platypoda in the Early or Middle Miocene and differentiated in the Late Miocene on the Korean Peninsula.Our results suggest that the divergence of F.chiisanensis was associated with the submergence of the East China Sea land bridge and enhanced monsoons in East Asia.When compared to F.platypoda,F.chiisanensis exhibits low genetic diversity within populations and high genetic differentiation among populations.These results help us to understand the evolutionary history of F.chiisanensis and to develop a conservation strategy for this species.
基金supported by the Biodiversity Conservation Research Project of Yunnan Environmental Protection Department (Grant no.Y430112261)
文摘With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combined data on the distribution of 1010 stenochoric endemic seed plants,vegetation constitution,geological history and climate change,and used these to propose a new system of floristic regions.We identified 11 distinct floristic subregions and 84 floristic provinces within Yunnan.Our work confirmed some views emphasized by Wu Zhengyi that the stenochoric endemic species play a key role in defining floristic provinces;that stenochoric endemic plants with long collection and publication histories are more valuable;that greater attention should be paid to woody plants;and that for Yunnan,a border region,some trans-border distributed elements should be treated cautiously.
文摘This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone across China ranging from North-East to South-West. Selenium contents in food grains and human hair from the disease affected areas are usually below 0.020ppm and 0.20ppm respectively. The endemic goitre caused by iodine deficiency distributes extensively in China, mainly in mountainous and hilly districts, swamp and peat areas, some sand soil and limestone areas. Also there is another kind of endemic goitre which caused by iodine excess in interior and coast areas. Endemic cretinism usually occurs in the endemic goitre seriously affected areas. Endemic fluorosis is also widely distributed in China, but mainly occurs in dry or semi-dry areas of north China. The fluoride sources for causing endemic fluorisis are drinking water and food grains polluted by coal smoke in the backing process of maize and chilli.
基金supported by the National Natural Science Foundation of China(31100394,31471981 and 31770462 to WY)Zhejiang Provincial Natural Science Foundation(LZ18C030002 to WY)China Scholarship Council(201506320019 to CC)
文摘Background: China has a relative high degree of endemism of birds due to its large area, diversified topography, and varied climates and habitats. Among the 77 Chinese endemic birds, 29 species are classified as threatened according to the officially released China Biodiversity Red List in 2015. Chinese endemic birds should be the focus of conservation because their local extinction in China means complete global extinction. However, to date, no study has explicitly examined the patterns and processes of extinction and threat in Chinese endemic birds. Methods: We obtained eleven biological traits and four extrinsic factors that are commonly hypothesized to influence extinction risk. After phylogenetic correction, these factors were used separately and in combination to assess their associations with extinction risk. Results: We found that 37.7% of Chinese endemic birds were listed as threatened (Vulnerable, Endangered and Critically Endangered). Small range size, high hunting vulnerability, and high human population density were important predictors of high extinction risk in Chinese endemic birds. Conclusions: Our study is the first to systematically investigate the patterns and processes of extinction risk in Chinese endemic birds. We suggest that endemic species with small range size and living in area with high human densities require conservation priorities. Conservation efforts should also focus on the reduction of human threats, such as human hunting and habitat degradation, for the effective preservation of Chinese endemic birds.
文摘Objective:To predict the factors associated with progression to severe dengue infection to prevent potentially fatal complications and to identify the determinants of severe complicated dengue.Methods:The study was conducted in a tertiary care hospitaldengue ward from September to November 2021 including confirmed dengue infected patients(positive NS1 antigen or antidengue-antibodies IgM).Secondary dengue infection was labelled by positive anti-dengue-antibodies IgG in active dengue infected patients.Detailed history,physical examination,laboratory and radiological parameters,hospital stay(days)and mortality percentages were noted.Patients were classified into three groups according to disease severity:dengue fever(DF),dengue hemorrhagic fever(DHF)and dengue shock syndrome(DSS).The predictors of complicated dengue infection were determined by regression analysis.Results:The most common symptom was fever(96.9%).Among 129 patients,62.8%had DF,31.0%had DHF and only 6.2%developed DSS.History of previous symptomatic dengue and positive anti-dengue-antibodies IgG were present in 100%DSS patients and nearly 75.0%DHF patients(P<0.05).The moratlity rate in patients with DSS,DHF and DF was 50.0%,2.5%and none respectively(P<0.05).Clinical parameters(body aches,bleeding,conjunctival hemorrhage,maculopapular rash,right hypochondrial tenderness,ascites,pleural effusion)and laboratory parameters(thrombocytopenia,raised alanine aminotransferase and secondary dengue infection)were determinants that complicate the dengue infection.Conclusions:Thrombocytopenia,raised alanine aminotransferase and secondary dengue infection are important laboratory parameters to complicate the disease process of dengue infection.
文摘The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other hand, an intake of 40 μg/d is required to maintain the plasma glutathione peroxidase (GPx) activity at plateau. Hence 40 μg/d is considered as the adequate dietary selenium requirement. Studies conducted in a chronic selenosis area indicate thai the toxic dietary selenlum inlake (adverse effect level), which would maintain the characteristic fingernail changes, was approximately 1600 μg/d. The mean value of dietary selenium intakes, which enabled the five patients to recover from fingernail lesions, was found to be 819 ±126μg/d. At a 95% confidence limit, the lower limit is around 600μg/d. Therefore, 600 and 400μg/d were suggested as the individual daily maximum safe selenium intake and the safe dietary selenium intake, respectively,The results were used in the prevention of Se-related endemic KD and Kashin-Beck disease (KBD)
文摘Dengue is one of the most common arthropod-borne viral diseases in humans and it is a leading cause of illness and death in the tropical and subtropical regions of the world. It is thought to account for 400 million cases annually among approximately 3.97 billion people at risk of infection in 128 endemic countries. Despite the global prevalence of the disease, the availability of a vaccine is limited in most countries in the endemic areas. Most endemic countries in South America, South East Asia and Africa serve as attractive touristic sites for people from non-endemic countries who become infected and export the virus to dengue-free regions. Dengue fever typically resembles malaria and in endemic countries most cases of dengue are treated as presumptive malaria. Consequently, routine dengue diagnosis among persons with fever will offer early treatment and reduce the burden of the disease. Also, routine testing among travellers from endemic countries will reduce importation and prevent the geographical expansion of dengue. In this essay, we seek to highlight the usefulness of routine dengue testing in endemic countries.
文摘Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species.In this study,the spatial distribution of five endemic and threatened species belonging to the genus Onosma(including O.asperrima,O.bisotunensis,O.kotschyi,O.platyphylla,and O.straussii)was investigated under present and future climate change scenarios:RCP2.6(RCP,representative concentration pathway;optimistic scenario)and RCP8.5(pessimistic scenario)for the years 2050 and 2080 in Iran.Analysis was conducted using the maximum entropy(MaxEnt)model to provide a basis for the protection and conservation of these species.Seven environmental variables including aspect,depth of soil,silt content,slope,annual precipitation,minimum temperature of the coldest month,and annual temperature range were used as main predictors in this study.The model output for the potential habitat suitability of the studied species showed acceptable performance for all species(i.e.,the area under the curve(AUC)>0.800).According to the models generated by MaxEnt,the potential current patterns of the species were consistent with the observed areas of distributions.The projected climate maps under optimistic and pessimistic scenarios(RCP2.6 and RCP8.5,respectively)of 2050 and 2080 resulted in reductions and expansions as well as positive range changes for all species in comparison to their current predicted distributions.Among all species,O.bisotunensis showed the most significant and highest increase under the pessimistic scenario of 2050 and 2080.Finally,the results of this study revealed that the studied plant species have shown an acute adaptability to environmental changes.The results can provide useful information to managers to apply appropriate strategies for the management and conservation of these valuable Iranian medicinal and threatened plant species in the future.
