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Eight Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacteria were isolated from six tobacco fields in Yunnan, PR China. 16S rRNA gene sequence analysis revealed that all the strains belonged to the genus Ralstonia. Among them, strain 22TCCZM03-6 had an identical 16S rRNA sequence to that of R. wenshanensis 56D2T, and the other strains were closely related to R. pickettii DSM 6297T (98.34-99.86%), R. wenshanensis 56D2T (98.70-99.64%), and R. insidiosa CCUG 46789T (97.34-98.56%). Genome sequencing yielded sizes ranging from 5.17 to 5.72 Mb, with overall G + C contents of 63.3-64.1%. Pairwise genome comparisons showed that strain 22TCCZM03-6 shared average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values above the species cut-off with R. wenshanensis 56D2T, suggesting that strain 22TCCZM03-6 is a special strain of the R. wenshanensis. Five strains, including 21MJYT02-10T, 21LDWP02-16, 22TCJT01-1, 22TCCZM01-4, and 22TCJT01-2, had ANI values >95% and dDDH values >70% when compared with each other. These five strains had ANI values of 73.32-94.17% and dDDH of 22.0-55.20% with the type strains of the genus Ralstonia individually, supporting these five strains as a novel species in the genus Ralstonia. In addition, strains 21YRMH01-3T and 21MJYT02-11T represent two independent species. They both had ANI and dDDH values below the thresholds for species delineation when compared with the type species of the genus Ralstonia. In strains 21YRMH01-3T and 21MJYT02-10T, the main fatty acids were summed features 3, 8, and C16:0; however, strain 21MJYT02-11T contained C16:0, cyclo-C17:0, and summed features 3 as major fatty acids. The main polar lipids, including diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine, were identified from strains 21YRMH01-3T, 21MJYT02-10T, and 21MJYT02-11T. The ubiquinones Q-7 and Q-8 were also detected in these strains, with Q-8 being the predominant quinone. Based on the above data, we propose that the eight strains represent one known species and three novel species in the genus Ralstonia, for which the names Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov. are proposed. The type strains are 21YRMH01-3T (=GDMCC 1.3534T = JCM 35818T), 21MJYT02-10T (=GDMCC 1.3531T = JCM 35816T), and 21MJYT02-11T (=GDMCC 1.3532T = JCM 35817T), respectively. [ABSTRACT FROM AUTHOR]

A Gram-negative, aerobic, rod-shaped, motile bacterium with multi-flagella, strain RST, was isolated from bacterial wilt of tobacco in Yuxi city of Yunnan province, China. The strain contains the major fatty acids of C16: 0, summed feature 3 (C16: 1 7c and/or C16: 1 6c), and summed feature 8 (C18: 1 7c and/or C18: 1 6c). The polar lipid profile of strain RST consists of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and unidentified aminophospholipid. Strain RST contains ubiquinones Q-7 and Q-8. 16S rRNA gene sequence (1,407 bp) analysis showed that strain RST is closely related to members of the genus Ralstonia and shares the highest sequence identities with R. pseudosolanacearum LMG 9673T (99.50%), R. syzygii subsp. indonesiensis LMG 27703T (99.50%), R. solanacearum LMG 2299T (99.28%), and R. syzygii subsp. celebesensis LMG 27706T (99.21%). The 16S rRNA gene sequence identities between strain RST and other members of the genus Ralstonia were below 98.00%. Genome sequencing yielded a genome size of 5.61 Mbp and a G + C content of 67.1 mol%. The genomic comparison showed average nucleotide identity (ANIb) values between strain RST and R. pseudosolanacearum LMG 9673T, R. solanacearum LMG 2299T, and R. syzygii subsp. indonesiensis UQRS 627T of 95.23, 89.43, and 91.41%, respectively, and the corresponding digital DNA-DNA hybridization (dDDH) values (yielded by formula 2) were 66.20, 44.80, and 47.50%, respectively. In addition, strains belonging to R. solanacearum phylotype I shared both ANIb and dDDH with strain RST above the species cut-off values of 96 and 70%, respectively. The ANIb and dDDH values between the genome sequences from 12 strains of R. solanacearum phylotype III (Current R. pseudosolanacearum) and those of strain RST were below the species cut-off values. Based on these data, we concluded that strains of phylotype I, including RST, represent a novel species of the genus Ralstonia, for which the name Ralstonia nicotianae sp. nov. is proposed. The type strain of Ralstonia nicotianae sp. nov. is RST (=GDMCC 1.3533T = JCM 35814T). [ABSTRACT FROM AUTHOR]

Kodamaea includes a growing number of interesting yeasts of the family Debaryomycetacae that are widely distributed in temperate, subtropical and tropical regions of different continents. During recent yeast collections in Henan and Yunnan Province in China, several isolates of Kodamaea were obtained from rotting wood, all of which represent undescribed taxa. Based on morphological and phylogenetic analyses (ITS and LSU rDNA), three new species are proposed: K. hongheensis f.a., sp. nov., K. ovata f.a., sp. nov. and K. yamadae f.a., sp. nov. In addition, sixteen Candida species, which are members of the Kodamaea clade based on phylogenetic analysis, are transferred to Kodamaea as new combinations. Our results indicate high species diversity of Kodamaea waiting to be discovered in rotting wood from tropical and subtropical China. [ABSTRACT FROM AUTHOR]

A systematic study of heavy metal levels, bioaccessibilities, and gastrointestinal cytotoxicity in two popular consumed vegetables mint (Mentha spicata Linn.) and pea sprouts (Pisum sativum Linn.) from three major producing cities in Yunnan, Southwest China were conducted for evaluating potential health risk to local inhabitants. The mean concentrations of As, Cd, Cr, and Pb were 0.34, 0.06, 1.04, and 0.79 mg/kg, respectively, with Cr and Pb exceeding 1.86-2.63 folds greater than the limit of Chinese National Standards and WHO/FAO. Their average gastric and intestinal bioaccessibilities varied within 12.1-59.4% and 9-53.3%, 0-93.3% and 0-82%, 41.8-71.1% and 19.1-62.9%, 16.1-93.6% and 9.5-81.7%, respectively. Cd in mint was the highest (86.8% and 39%, in the gastric phase and intestinal phase), while Pb had the highest bioaccessibility of 69.9% and 48.7% in pea sprouts. The bioaccessible target hazard quotient (BTHQ) of As, Cr, and Pb from vegetables reflected no potential health risks. However, toxicity assays showed intestinal digesta induced significant cytotoxicity in human intestinal Caco-2 cells, indicating the existing models based on total or bioaccessible heavy metals may be not accurate enough to assess their human health risk, especially for adverse effects evaluation. Taken together, the human risk assessment should be modified by taking their gastrointestinal cytotoxicity into account. [ABSTRACT FROM AUTHOR]

Here, we present the complete genome sequence and annotation of Ralstonia syzygii subsp. indonesiensis strain LLRS-1, which caused bacterial wilt on flue-cured tobacco in Yunnan Province, southwest China. Strain LLRS-1 is the first R. syzygii strain identified to be pathogenic to tobacco in China. The completely assembled genome of strain LLRS-1 consists of a 3,648,314-bp circular chromosome and a 2,046,405-bp megaplasmid with 5,190 protein-coding genes, 55 transfer RNAs, 28 small RNAs, 3 structural RNAs (5S, 16S, and 23S), and a G+C content of 67.05%. [ABSTRACT FROM AUTHOR]

Yamadazyma is one of the largest genera in the family Debaryomycetaceae (Saccharomycetales, Saccharomycetes) with species mainly found in rotting wood, insects and their resulting frass, but also recovered from flowers, leaves, fruits, tree bark, mushrooms, sea water, minerals, and the atmosphere. In the present study, several strains obtained from rotting wood in Henan and Yunnan Provinces of China were isolated. Based on morphology and a molecular phylogeny of the rDNA internal transcribed spacer region (ITS) and the D1/D2 domain of the large subunit (LSU) rDNA, these strains were identified as three new species: Yamadazyma luoyangensis, Y. ovata and Y. paraaseri; and three previously described species, Y. insectorum, Y. akitaensis, and Y. olivae. The three new species are illustrated and their morphology and phylogenetic relationships with other Yamadazyma species are discussed. Our results indicate a high undiscovered diversity of Yamadazyma spp. inhabiting rotting wood in China. [ABSTRACT FROM AUTHOR]

The toxicity of arsenic (As) in different polluted areas and its effects on human and animal health is a big concern all over the world. Although a wetland ecosystem is a "green filter," this specific function would be impaired by high As content in wetland sediments. The distribution of As in wetland sediments and its linkages to environmental factors have not been fully explored. In this study, sediment samples (0-10 cm) and water samples were collected from different locations along the Yangzonghai lakeside, located in the city of Yuxi, Yunnan province of China, and were analyzed for As fractions. Results showed that As content in sediments ranged from 7.550 to 89.83 mg·kg-1 (with a mean value of 16.11 mg·kg-1). The As fractions were dominated by residual fraction (B4) (up to 62.67%), and the mean contents from high to low were: B4 (10.10) > oxidizable fraction (B3) (2.600) > acid extractable fraction (B1) (2.270) > reducible fraction (B2) (2.170). The distribution of As in sediments was mainly influenced by point-source pollution. In addition, the lack of significant correlation between As content and the different landscapes in the buffer zone of Yangzonghai lakeside indicated that the land use around the lakeside wetland (mainly non-point source pollution) may not have a significant impact on As fractions. Among environmental factors, As contents were positively (p<0.05) correlated to dicalcium phosphate (Ca2-P) and octacalcium phosphate (Ca8-P). However, phosphorus distribution revealed that phosphorus in sediments was mainly caused by non-point source pollution, and thus farmland fertilizer, domestic waste, and livestock manure should be controlled. As fractions such as B1, B2, and B3 in wetland sediments were positively correlated with dissolved oxygen (DO) and redox potential (Eh), but negatively correlated to organic matter (OM), pH, and lime-type phosphorus (Ca10-P) when the upstream area was dominated by agricultural lands, indicating that these parameters may affect the release of As into sediments. [ABSTRACT FROM AUTHOR]