Metagenome-assembled genomes reveal carbohydrate degradation and element metabolism of microorganisms inhabiting Tengchong hot springs, China.

A hot spring is a distinctive aquatic environment that provides an excellent system to investigate microorganisms and their function in elemental cycling processes. Previous studies of terrestrial hot springs have been mostly focused on the microbial community, one special phylum or category, or genes involved in a particular metabolic step, while little is known about the overall functional metabolic profiles of microorganisms inhabiting the terrestrial hot springs. Here, we analyzed the microbial community structure and their functional genes based on metagenomic sequencing of six selected hot springs with different temperature and pH conditions. We sequenced a total of 11 samples from six hot springs and constructed 162 metagenome-assembled genomes (MAGs) with completeness above 70% and contamination lower than 10%. Crenarchaeota, Euryarchaeota and Aquificae were found to be the dominant phyla. Functional annotation revealed that bacteria encode versatile carbohydrate-active enzymes (CAZYmes) for the degradation of complex polysaccharides, while archaea tend to assimilate C1 compounds through carbon fixation. Under nitrogen-deficient conditions, there were correspondingly fewer genes involved in nitrogen metabolism, while abundant and diverse set of genes participating in sulfur metabolism, particularly those associated with sulfide oxidation and thiosulfate disproportionation. In summary, archaea and bacteria residing in the hot springs display distinct carbon metabolism fate, while sharing the common energy preference through sulfur metabolism. Overall, this research contributes to a better comprehension of biogeochemistry of terrestrial hot springs.

Transcriptome Profile Analysis Identifies Candidate Genes for the Melanin Pigmentation of Skin in Tengchong Snow Chickens.

Tengchong Snow chickens are one of the most precious, black-boned chickens in Yunnan province and usually produce black meat. However, we found a small number of white meat traits in the chicken population during feeding. In order to determine the pattern of melanin deposition and the molecular mechanism of formation in the Tengchong Snow chicken, we measured the luminance value (L value) and melanin content in the skin of black meat chickens (Bc) and white meat chickens (Wc) using a color colorimeter, ELISA kit, and enzyme marker. The results showed that the L value of skin tissues in black meat chickens was significantly lower than that of white meat chickens, and the L value of skin tissues gradually increased with an increase in age. The melanin content of skin tissues in black meat chickens was higher than that of white meat chickens, and melanin content in the skin tissues gradually decreased with an increase in age, but this difference was not significant (p > 0.05); the L value of skin tissues in black meat chickens was negatively correlated with melanin content, and the correlation coefficient was mostly above -0.6. In addition, based on the phenotypic results, we chose to perform the comparative transcriptome profiling of skin tissues at 90 days of age. We screened a total of 44 differential genes, of which 32 were upregulated and 12 were downregulated. These DEGs were mainly involved in melanogenesis, tyrosine metabolism and RNA transport. We identified TYR, DCT, and EDNRB2 as possible master effector genes for skin pigmentation in Tengchong Snow black meat chickens through DEGs analysis. Finally, we measured the mRNA of TYR, DCT, MC1R, EDNRB2, GPR143, MITF, and TYRP1 genes through a quantitative real-time polymerase chain reaction (qPCR) and found that the mRNA of all the above seven genes decreased with increasing age. In conclusion, our study initially constructed an evaluation system for the black-boned traits of Tengchong Snow chickens and found key candidate genes regulating melanin deposition, which could provide an important theoretical basis for the selection and breeding of black-boned chickens.

Methanogens-Driven Arsenic Methylation Preceding Formation of Methylated Thioarsenates in Sulfide-Rich Hot Springs.

Hot springs represent a major source of arsenic release into the environment. Speciation is typically reported to be dominated by arsenite, arsenate, and inorganic thiolated arsenates. Much less is known about the relevance and formation of methylated thioarsenates, a group with species of high mobility and toxicity. In hot spring samples taken from the Tengchong volcanic region in China, methylated thioarsenates contributed up to 13% to total arsenic. Enrichment cultures were obtained from the corresponding sediment samples and incubated to assess their capability to convert arsenite into methylated thioarsenates over time and in the presence of different microbial inhibitors. In contrast to observations in other environmental systems (e.g., paddy soils), there was no solid evidence, supporting that the sulfate-reducing bacteria contributed to the arsenic methylation. Methanosarcina, the sole genus of methanogens detected in the enrichment cultures, as well as Methanosarcina thermophila TM-1, a pure strain within the genus, did methylate arsenic. We propose that methylated thioarsenates in a typical sulfide-rich hot spring environment like Tengchong form via a combination of biotic arsenic methylation driven by thermophilic methanogens and arsenic thiolation with either geogenic sulfide or sulfide produced by sulfate-reducing bacteria.

Isolation of archaeal viruses with lipid membrane from Tengchong acidic hot springs.

Archaeal viruses are one of the most mysterious parts of the virosphere because of their diverse morphologies and unique genome contents. The crenarchaeal viruses are commonly found in high temperature and acidic hot springs, and the number of identified crenarchaeal viruses is being rapidly increased in recent two decades. Over fifty viruses infecting the members of the order Sulfolobales have been identified, most of which are from hot springs distributed in the United States, Russia, Iceland, Japan, and Italy. To further expand the reservoir of viruses infecting strains of Sulfolobaceae, we investigated virus diversity through cultivation-dependent approaches in hot springs in Tengchong, Yunnan, China. Eight different virus-like particles were detected in enrichment cultures, among which five new archaeal viruses were isolated and characterized. We showed that these viruses can infect acidophilic hyperthermophiles belonging to three different genera of the family Sulfolobaceae, namely, Saccharolobus, Sulfolobus, and Metallosphaera. We also compared the lipid compositions of the viral and cellular membranes and found that the lipid composition of some viral envelopes was very different from that of the host membrane. Collectively, our results showed that the Tengchong hot springs harbor highly diverse viruses, providing excellent models for archaeal virus-host studies.

Use of modified ichip for the cultivation of thermo-tolerant microorganisms from the hot spring.

BACKGROUND: Thermostable microorganisms are extremophiles. They have a special genetic background and metabolic pathway and can produce a variety of enzymes and other active substances with special functions. Most thermo-tolerant microorganisms from environmental samples have resisted cultivation on artificial growth media. Therefore, it is of great significance to isolate more thermo-tolerant microorganisms and study their characteristics to explore the origin of life and exploit more thermo-tolerant enzymes. Tengchong hot spring in Yunnan contains a lot of thermo-tolerant microbial resources because of its perennial high temperature. The ichip method was developed by D. Nichols in 2010 and can be used to isolate so-called "uncultivable" microorganisms from different environments. Here, we describe the first application of modified ichip to isolate thermo-tolerant bacteria from hot springs. RESULTS: In this study, 133 strains of bacteria belonging to 19 genera were obtained. 107 strains of bacteria in 17 genera were isolated by modified ichip, and 26 strains of bacteria in 6 genera were isolated by direct plating methods. 25 strains are previously uncultured, 20 of which can only be cultivated after being domesticated by ichip. Two strains of previously unculturable Lysobacter sp., which can withstand 85 °C, were isolated for the first time. Alkalihalobacillus, Lysobacter and Agromyces genera were first found to have 85 °C tolerance. CONCLUSION: Our results indicate that the modified ichip approach can be successfully applied in a hot spring environment.

Hyperpigmentation Inhibits Early Skeletal Muscle Development in Tengchong Snow Chicken Breed.

Tengchong snow, which has white feathers and black meat, is one of the most important black-bone chicken breeds and a genetic treasure of black food in China. Although the black meat traits are dominant, there are some chickens with white meat traits born in the process of folk selection and breeding. The purpose of this study was to compare the differences in skeletal muscle development between Tengchong snow black meat chickens (BS) and white meat chickens (WS), as well as whether excessive melanin deposition has an effect on skeletal muscle development. The BS and WS groups were selected to determine their muscle development difference at stages of 1, 7, 14, 21, and 42 days, using histological stain methods to analyze the development and composing type of breast and leg muscle fibers, as well as the count of melanin in BS muscle fibers. Finally, we were validated key candidate genes associated with muscle development and melanin synthesis. The results showed that BS breast muscle development was inhibited at 7, 14, and 21 days, while the leg muscle was inhibited at 7, 14, 21, and 42 days, compared to WS. Melanin deposition was present in a temporal migration pattern and was greater in the leg muscles than in the breast muscles, and it focused around blood vessels, as well as the epithelium, perimysium, endomysium, and connective tissue. Additionally, melanin produced an inhibitory effect similar to MSTN during skeletal muscle fiber development, and the inhibition was strongest at the stage of melanin entry between muscle fibers, but the precise mechanisms need to be confirmed. This study revealed that melanin has an inhibitory effect on the early development of skeletal muscle, which will provide new insights into the role of melanin in the black-boned chicken and theoretical references for the future conservation and utilization of black-boned chicken.

nifH gene expression and diversity in geothermal springs of Tengchong, China.

Terrestrial hot springs have been suggested to harbor diverse diazotrophic lineages by using DNA-based nifH gene phylogenetic analysis. However, only a small amount of diazotrophs were ever confirmed to perform nitrogen fixation. In order to explore the compositions of active diazotrophic populations in hot springs, the in situ expression and diversity of nifH and 16S rRNA genes were investigated in the sediments of hot springs (pH 4.3-9.1; temperature 34-84°C) in Tengchong, China, by using high-throughput sequencing. The results showed that active diazotrophs were diverse in the studied Tengchong hot springs. The main active diazotrophs in high-temperature hot springs were affiliated with Aquificae, while those in low-temperature hot springs belonged to Cyanobacteria and Nitrospirae. Such dominance of Aquificae and Nitrospirae of diazotrophs has not been reported in other ecosystems. This suggests that hot springs may harbor unique active diazotrophs in comparison with other type of ecosystems. Furthermore, there were significant differences in the phylogenetic lineages of diazotrophs between hot springs of Tengchong and other regions, indicating that diazotrophs have geographical distribution patterns. Statistical analysis suggests that the expression and distribution of nifH gene were influenced by temperature and concentrations of ammonia and sulfur seem in Tengchong hot springs. These findings avail us to understand element cycling mediated by diazotrophs in hot spring ecosystems.

Qipengyuania thermophila sp. nov., isolated from a Chinese hot spring.

A novel Gram-stain-negative, non-motile, short rod-shaped and aerobic bacterial strain, designated as CFH 74456 T, was isolated from sediment of a hot spring, Tengchong, Yunnan Province, south-western China. Growth occurred at 20-53 ºC (optimum 45 ºC), pH 7.0-9.0 (optimum pH 8.0) and up to 2.0% (w/v) NaCl (optimum 0-1.0%, w/v). The predominant respiratory quinone was ubiquinone 10 (Q-10). The major fatty acids (> 10%) were C17:1 ω6c (17.9%) and summed feature 8 (38.6%). The polar lipid profile of strain CFH 74456 T was identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, three unidentified glycolipids and three unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CFH 74456 T belongs to the genus Qipengyuania, and was most closely related to Qipengyuania sediminis CGMCC 1.12928 T (95.7%). The draft genome size of the isolate was 2.29 Mb with G + C content of 68.5%. The amino acid identity, average nucleotide identity and the digital DNA-DNA hybridization values between strain CFH 74456 T and the closest relatives ranged from 67.0 to 67.9%, 73.0 to 74.2% and 18.2-19.3%, respectively. On the basis of phenotypic, phylogenetic and genotypic analyses, it is concluded that strain CFH 74456 T represents a new species of the genus Qipengyuania, for which the name Qipengyuania thermophila sp. nov. is proposed. The type strain is CFH 74456 T (= KCTC 62921 T = CCTCC AB 2018237 T).

Increasing risk of aphids spreading plant viruses in maize fields on both sides of China's Heihe-Tengchong line under climate change.

BACKGROUND: In the coming decades, geographical distribution patterns of farmland organisms may undergo drastic changes due to climate change, with significant implications for global food security. In China, Rhopalosiphum maidis and its spread of sugarcane mosaic virus (ScMV) can become an increasingly serious threat to maize (Zea mays) production. We conducted ecological niche modeling for Z. mays, R. maidis, and ScMV under current and future (2041-2060 and 2081-2100) climate scenarios by using MaxEnt software to explore changes in this system. RESULTS: The Heihe-Tengchong line (an imaginary separation line of human population density) can divide China into main (east of the line) and secondary (west of the line) habitats for the three species. With climate change, rapid expansion in suitable areas is projected for ScMV and the aphid vector R. maidis. Taking species interactions into consideration, our overlaying analyses show that most areas east of the Heihe-Tengchong line (optimal for maize and suitable for R. maidis) will become increasingly highly suitable for ScMV, suggesting that the prevention and control of this plant virus and its aphid vector in China's main maize-growing areas (e.g. northeast) will become an increasing challenge in the future. CONCLUSION: Climate change will profoundly affect ScMV-vector-maize interactions, which may contribute favorably to invasion of this virus into new areas. Our comprehensive and in-depth analyses on shifts in this multi-species system under climate change provide useful and insightful information for devising strategies for the prevention and control of plant viruses and aphid vectors on maize in the future. © 2022 Society of Chemical Industry.

Molecular epidemiology of mosquito-borne viruses at the China-Myanmar border: discovery of a potential epidemic focus of Japanese encephalitis.

BACKGROUND: Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province-which borders Myanmar-is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. METHODS: We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July-October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. RESULTS: Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4-3.9). CONCLUSIONS: A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens.

Prevalence of Entamoeba histolytica infection and its risk factors in Tengchong City, Yunnan Provine: a hospital-based study / 中国血吸虫病防治杂志

Objective To understand the infection status and risk factors of Entamoeba histolytica in inpatients in Tengchong City, Yunnan Province. Methods A cross-sectional study was conducted in the inpatients in Tengchong People’s Hospital, Yunnan Province. After obtaining the informed consent from the subjects, the stool samples were collected from 2016-07-01 to 2017-03-31, and nested polymerase chain reaction (PCR) was used to detect E. histolytica in the stool samples. Meanwhile, a structured questionnaire was used to record the demographic information and clinical symptoms for the patients. Results Totally 507 cases were recruited, and the detection rate of E. histolytica was 1.97% (10/507, 95% CI: 1.07%-3.59%) in all subjects. There were no significant differences between the inpatients with and without E. histolytica infection in the height (Z = -0.40, P = 0.69), weight (Z = -0.34, P = 0.73), body mass index (Z = -0.40, P = 0.69) and age (Z = -1.48, P = 0.14). Chronic diarrhea (OR = 21.43, 95% CI: 5.04-91.23) and daily drinking water (OR = 11.28, 95% CI: 2.79-45.56) were relevant to E. histolytica infection. No significant association was observed between E. histolytica infection and the clinical symptoms, such as abdominal distension (OR = 0.70, 95% CI: 0.09-5.56), inappetence (OR = 0.50, 95% CI: 0.06-4.02), itchy skin (OR = 0.79, 95% CI: 0.10-6.38), perianal pruritus (OR = 1.74, 95% CI: 0.21-14.07), and constipation (OR = 0.91, 95% CI: 0.13-7.33). Conclusion E. histolytica infection is high in inpatients in Tengchong City, Yunnan Province, and chronic diarrhea and drinking unboiled water were highly correlated with E. histolytica infection.

Physiological and genomic properties of Thermus tenuipuniceus sp. nov., a novel slight reddish color member isolated from a terrestrial geothermal spring.

Two closely related, thermophilic bacteria, designated strains YIM 76954T and YIM 76947, were isolated from the Rehai Geothermal Field, Tengchong, Yunnan province, south-west China. Polyphasic approach and whole genome sequencing were used to determine the taxonomy status and genomic profiles of the novel strains. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates were closely related to Thermus scotoductus SE-1T (97.1% sequence similarity), and T. amyloliquefaciens YIM 77409T (96.6%). The strains could be differentiated from most recognized Thermus species by their whitish to slight reddish colony color, distinct DNA fingerprinting profiles and low ANI values. Cells stained Gram-negative, rod-shaped of diameter 0.2-0.5µm and length 1.5-5.0µm. Growth occurred at 50-75°C, pH 6.0-9.0 and in the presence of up to 1.0% (w/v) NaCl concentration. Thiosulfate was found to enhance cell growth, besides improving the intensity of its colony color. Oxygen, nitrate, sulfur, and Fe(III) could be used as terminal electron acceptors for growth. MK-8 was the major respiratory menaquinone. Major fatty acids were iso-C17:0, iso-C15:0, anteiso-C17:0, and anteiso-C15:0. The genome size was 2.26Mbp with 65.5% average GC content. A total of 2374 genes was predicted, comprising 2322 protein-coding and 52 RNA genes. On the basis of the polyphasic evidence presented, it is proposed that strain YIM 76954T represents a novel species of the genus Thermus, for which the name Thermus tenuipuniceus sp. nov. is proposed. The type strain is YIM 76954T (=JCM 30350T=KCTC 4677T).

High genetic diversity in hard ticks from a China-Myanmar border county.

BACKGROUND: Many tick species have great morphological similarity and are thus grouped into species complexes. Molecular methods are therefore useful in the classification and identification of ticks. However, little is known about the genetic diversity of hard ticks in China, especially at the subspecies level. Tengchong is one of the epidemic foci of tick-borne diseases in China, but the tick species inhabiting the local area are still unknown. METHODS: Eighteen villages in Tengchong County, China, were selected for sampling carried out from September to October 2014. Infesting hard ticks were removed from the body surface of domestic animals and questing ticks were collected from grazing fields. After morphological identification, molecular characteristics of each tick species were analyzed based on both 16S rRNA and cytochrome c oxidase subunit 1 (cox1) gene fragments. RESULTS: Six tick species were identified based on morphology: Rhipicephalus microplus, R. haemaphysaloides, Ixodes ovatus, Haemaphysalis longicornis, H. shimoga and H. kitaokai. Phylogenetic analysis using the cox1 gene revealed that R. microplus ticks from the present study belong to clade C. For tick samples of both R. haemaphysaloides and I. ovatus, three phylogenetic groups were recognized, and the intergroup genetic distances exceeded the usual tick species boundaries. Haemaphysalis longicornis ticks were clustered into two separate clades based on the cox1 gene. For ticks from both H. shimoga and H. kitaokai, two phylogenetic groups were recognized based on the phylogenetic analysis of the 16S rRNA gene, and the intergroup genetic distances also exceeded the known boundaries for closely related tick species. CONCLUSIONS: According to molecular analyses, new species or subspecies closely related to R. haemaphysaloides, I. ovatus, H. shimoga and H. kitaokai probably exist in the China-Myanmar border Tengchong County, or these ticks form species complexes with highly divergent mitochondrial lineages. Morphological comparisons are warranted to further confirm the taxonomic status of these tick species.

Unexpected fungal communities in the Rehai thermal springs of Tengchong influenced by abiotic factors.

Fungal communities represent an indispensable part of the geothermal spring ecosystem; however, studies on fungal community within hot springs are still scant. Here, we used Illumina HiSeq 2500 sequencing to detect fungal community diversity in extremely acidic hot springs (pH < 4) and neutral and alkaline springs (pH > 6) of Tengchong-indicated by the presence of over 0.75 million valid reads. These sequences were phylogenetically assigned to 5 fungal phyla, 67 order, and 375 genera, indicating unexpected fungal diversity in the hot springs. The genera such as Penicillium, Entyloma, and Cladosporium dominated the fungal community in the acidic geothermal springs, while the groups such as Penicillium, Engyodontium, and Schizophyllum controlled the fungal assemblages in the alkaline hot springs. The alpha-diversity indices and the abundant fungal taxa were significantly correlated with physicochemical factors of the hot springs particularly pH, temperature, and concentrations of Fe2+, NH4+, NO 2-, and S2-, suggesting that the diversity and distribution of fungal assemblages can be influenced by the complex environmental factors of hot springs.

[Prevalence of Entamoeba histolytica infection and its risk factors in Tengchong City, Yunnan Provine: a hospital-based study].

OBJECTIVE: To understand the infection status and risk factors of Entamoeba histolytica in inpatients in Tengchong City, Yunnan Province. METHODS: A cross-sectional study was conducted in the inpatients in Tengchong People's Hospital, Yunnan Province. After obtaining the informed consent from the subjects, the stool samples were collected from 2016-07-01 to 2017-03-31, and nested polymerase chain reaction (PCR) was used to detect E. histolytica in the stool samples. Meanwhile, a structured questionnaire was used to record the demographic information and clinical symptoms for the patients. RESULTS: Totally 507 cases were recruited, and the detection rate of E. histolytica was 1.97% (10/507, 95% CI: 1.07%-3.59%) in all subjects. There were no significant differences between the inpatients with and without E. histolytica infection in the height (Z = -0.40, P = 0.69), weight (Z = -0.34, P = 0.73), body mass index (Z = -0.40, P = 0.69) and age (Z = -1.48, P = 0.14). Chronic diarrhea (OR = 21.43, 95% CI: 5.04-91.23) and daily drinking water (OR = 11.28, 95% CI: 2.79-45.56) were relevant to E. histolytica infection. No significant association was observed between E. histolytica infection and the clinical symptoms, such as abdominal distension (OR = 0.70, 95% CI: 0.09-5.56), inappetence (OR = 0.50, 95% CI: 0.06-4.02), itchy skin (OR = 0.79, 95% CI: 0.10-6.38), perianal pruritus (OR = 1.74, 95% CI: 0.21-14.07), and constipation (OR = 0.91, 95% CI: 0.13-7.33). CONCLUSIONS: E. histolytica infection is high in inpatients in Tengchong City, Yunnan Province, and chronic diarrhea and drinking unboiled water were highly correlated with E. histolytica infection.

Prevalence of Entamoeba histolytica infection and its risk factors in Tengchong City, Yunnan Provine: a hospital-based study / 中国血吸虫病防治杂志

Objective To understand the infection status and risk factors of Entamoeba histolytica in inpatients in Tengchong City, Yunnan Province. Methods A cross-sectional study was conducted in the inpatients in Tengchong People’s Hospital, Yunnan Province. After obtaining the informed consent from the subjects, the stool samples were collected from 2016-07-01 to 2017-03-31, and nested polymerase chain reaction (PCR) was used to detect E. histolytica in the stool samples. Meanwhile, a structured questionnaire was used to record the demographic information and clinical symptoms for the patients. Results Totally 507 cases were recruited, and the detection rate of E. histolytica was 1.97% (10/507, 95% CI: 1.07%-3.59%) in all subjects. There were no significant differences between the inpatients with and without E. histolytica infection in the height (Z = -0.40, P = 0.69), weight (Z = -0.34, P = 0.73), body mass index (Z = -0.40, P = 0.69) and age (Z = -1.48, P = 0.14). Chronic diarrhea (OR = 21.43, 95% CI: 5.04-91.23) and daily drinking water (OR = 11.28, 95% CI: 2.79-45.56) were relevant to E. histolytica infection. No significant association was observed between E. histolytica infection and the clinical symptoms, such as abdominal distension (OR = 0.70, 95% CI: 0.09-5.56), inappetence (OR = 0.50, 95% CI: 0.06-4.02), itchy skin (OR = 0.79, 95% CI: 0.10-6.38), perianal pruritus (OR = 1.74, 95% CI: 0.21-14.07), and constipation (OR = 0.91, 95% CI: 0.13-7.33). Conclusion E. histolytica infection is high in inpatients in Tengchong City, Yunnan Province, and chronic diarrhea and drinking unboiled water were highly correlated with E. histolytica infection.

Rhabdanaerobium thermarum gen. nov., sp. nov., a novel anaerobic bacterium isolated from a hot spring.

A novel Gram-stain-positive, obligately anaerobic and thermophilic bacterium, strain SYSU GA15001T, was isolated from a sample collected from a hot spring located in Tengchong, China. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SYSU GA15001T belonged to the family Eubacteriaceae, and was closely related to 'Irregularibacter muris' 2PG-426-CC4.2T (93.6 % similarity), Garciella nitratireducens DSM 15102T (93.2 %) and Alkalibacter saccharofermentans Z-78920T (89.7 %). Cells were rods and motile by means of a subpolar flagellum. Spores were formed in old cultures. Optimum growth was observed at 45 °C, at pH 7 and in the presence of 1.5 % (w/v) NaCl. The strain utilized d-arabinose, dulcitol, d-galactose, glucose, lactose, maltose, d-mannose, raffinose, l-rhamnose, d-sorbitol, xylitol, l-alanine, l-arginine, glycine, l-isoleucine, l-leucine, dl-methionine, NH4Cl, l-proline and l-threonine as sole carbon/nitrogen sources. Additionally, complex substrates including beef extract, peptone, starch and yeast extract can also be used as sole energy sources. The major fatty acid methyl esters were C14 : 0, anteiso-C15 : 0 and C18 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unidentified polar lipid, three unidentified phospholipids and an unidentified glycolipid. The DNA G+C content was determined to be 35.6 mol%. Strain SYSU GA15001T was physiologically and phylogenetically distinguishable from its closely related genera, and merits assignment as representing the type species of a new genus Rhabdanaerobium, with the name Rhabdanaerobium thermarum gen. nov., sp. nov. The type strain of the type species is SYSU GA15001T (=CGMCC 1.5219T=KCTC 15623T).

Caldovatus sediminis gen. nov., sp. nov., a moderately thermophilic bacterium isolated from a hot spring.

A Gram-stain-negative, ovoid-shaped, aerobic, non-motile, catalase- and oxidase-positive, and moderately thermophilic bacterial strain, designated strain YIM 72346T, was isolated from a sediment sample collected from a hot spring in Tengchong county, Yunnan province, south-west China. Growth occurred at 37-50 °C (optimum, 45 °C), at pH 6.0-9.0 (optimum, pH 6.5-7.0) and in the presence of 0.5-1.0 % (w/v) NaCl (optimum, 0.5 %). The major cellular fatty acids were C18 : 1ω7c, C16 : 0, C19 : 0cyclo ω8c,and C18 : 1 2-OH. The genomic DNA G+C content was determined to be 69.8 mol%. The predominant ubiquinone was Q-10. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and two unidentified phospholipids. Bacteriochlorophyll α and carotenoic acids were not detected. Strain YIM 72346T was not observed for the accumulation of poly-ß-hydroxybutyrate. The strain shared highest 16S rRNA gene sequence identities with Crenalkalicoccus roseus YIM 78023T (93.3 %) and Craurococcus roseus NS130T (92.7 %), but formed a distinct lineage within the family Acetobacteraceae in the phylogenetic trees. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenetic analyses, strain YIM 72346T is considered to represent a novel genus and species of the family Acetobacteraceae, for which the name Caldovatus sediminis gen. nov., sp. nov. is proposed. The type strain of Caldovatus sediminis is YIM 72346T (=KCTC 52714T=CGMCC 1.16330T).

[Malaria focus investigation and disposal in Tengchong City between 2015 and 2016].

OBJECTIVE: To analyze the results of malaria focus investigation and disposal in Tengchong City, Yunnan Province between 2015 and 2016, so as to provide evidences for interrupting potential malaria transmission. METHODS: The malaria foci were investigated and disposed according to the malaria cases reported from "China Information System for Disease Control and Prevention" in Tengchong City between 2015 and 2016. The mosquitoes were captured by mosquito-lured lamp overnight to investigate the malaria vector in local. The peripheral blood samples were collected from the local residents with a febrile history in the foci within two weeks and the accompanists of the cases, and then the rapid malaria diagnosis tests were used to screen the malaria carriers. RESULTS: Totally 145 imported malaria cases were reported in Tengchong City between 2015 and 2016, and the focus investigation and disposal rate within 7 d was 100% (145/145). A total of 16 186 mosquitoes of 12 species of Anopheles were captured, among which An. sinensis was the predominant, accounting for 64.31% (10 410/16 186), followed by An. kunmingensis and An. minimus, with the constituent ratios of 14.15% (2 291/16 186) and 11.66% (1 887/16 186), respectively. One person (1.96%, 1/51) in the 51 accompanists of the cases was positive in the malaria rapid diagnosis test. CONCLUSIONS: The malaria transmission vectors such as An. sinensis, An. kunmingensis, An. minimus etc. are still distributed in Tengchong City, and An. sinensis is the predominant species. Therefore, the relevant authorities should continue to strengthen the focus investigation and disposal to interrupt the potential introduced malaria transmission by imported cases in the future.

Malaria focus investigation and disposal in Tengchong City between 2015 and 2016 / 中国血吸虫病防治杂志

Objective To analyze the results of malaria focus investigation and disposal in Tengchong City,Yunnan Prov-ince between 2015 and 2016,so as to provide evidences for interrupting potential malaria transmission. Methods The malaria foci were investigated and disposed according to the malaria cases reported from"China Information System for Disease Control and Prevention"in Tengchong City between 2015 and 2016. The mosquitoes were captured by mosquito-lured lamp overnight to investigate the malaria vector in local. The peripheral blood samples were collected from the local residents with a febrile history in the foci within two weeks and the accompanists of the cases,and then the rapid malaria diagnosis tests were used to screen the malaria carriers. Results Totally 145 imported malaria cases were reported in Tengchong City between 2015 and 2016,and the focus investigation and disposal rate within 7 d was 100%(145/145). A total of 16186 mosquitoes of 12 species of Anopheles were captured,among which An. sinensis was the predominant,accounting for 64.31%(10410/16186),followed by An. kun-mingensis and An. minimus,with the constituent ratios of 14.15%(2291/16186)and 11.66%(1887/16186),respectively. One person(1.96%,1/51)in the 51 accompanists of the cases was positive in the malaria rapid diagnosis test. Conclusions The malaria transmission vectors such as An. sinensis,An. kunmingensis,An. minimus etc. are still distributed in Tengchong City,and An. sinensis is the predominant species. Therefore,the relevant authorities should continue to strengthen the focus in-vestigation and disposal to interrupt the potential introduced malaria transmission by imported cases in the future.