Publications by authors named "Wen-Jun Li"

737 Publications

Physicochemical and Microbial Diversity Analyses of Indian Hot Springs.

Front Microbiol 2021 3;12:627200. Epub 2021 Mar 3.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China.

In the present study, physicochemical and microbial diversity analyses of seven Indian hot springs were performed. The temperature at the sample sites ranged from 32 to 67°C, and pH remained neutral to slightly alkaline. pH and temperature influenced microbial diversity. Culture-independent microbial diversity analysis suggested bacteria as the dominant group (99.3%) when compared with the archaeal group (0.7%). Alpha diversity analysis showed that microbial richness decreased with the increase of temperature, and beta diversity analysis showed clustering based on location. A total of 131 strains (divided into 12 genera and four phyla) were isolated from the hot spring samples. Incubation temperatures of 37 and 45°C and T5 medium were more suitable for bacterial isolation. Some of the isolated strains shared low 16S rRNA gene sequence similarity, suggesting that they may be novel bacterial candidates. Some strains produced thermostable enzymes. Dominant microbial communities were found to be different depending on the culture-dependent and culture-independent methods. Such differences could be attributed to the fact that most microbes in the studied samples were not cultivable under laboratory conditions. Culture-dependent and culture-independent microbial diversities suggest that these springs not only harbor novel microbial candidates but also produce thermostable enzymes, and hence, appropriate methods should be developed to isolate the uncultivated microbial taxa.
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http://dx.doi.org/10.3389/fmicb.2021.627200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7982846PMC
March 2021

gen. nov., sp. nov., a new actinobacterium isolated from hot spring sediment, and emended description of the family .

Int J Syst Evol Microbiol 2019 Jun 19;71(3). Epub 2021 Mar 19.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China.

One thermophilic bacterium, designated strain SYSU G02662, was isolated from hot spring sediment sampled in Tibet, PR China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomy position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G02662 showed the highest sequence similarity to SCSIO 58843 (95.1 %). The strain could be differentiated from other species of the family by its distinct phenotypic and genotypic characteristics. Cells of strain SYSU G02662 were aerobic, Gram-staining-positive and short rodshaped. Growth occurred optimally at 45 °C and pH 7.0. In addition, -diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The respiratory quinone was MK-9 (H), while the major fatty acids (>10 %) were C, C, C and iso-C. The detected polar lipids included diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The G+C content of the genomic DNA was 70.5 % based on the draft genomic sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G02662 represents a novel species of a novel genus in the family , for which the name gen. nov., sp. nov. is proposed. The type strain of the proposed novel species is SYSU G02662 (=CGMCC 4.7688=KCTC 49500).
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http://dx.doi.org/10.1099/ijsem.0.004760DOI Listing
June 2019

Evaluation of Sample Preservation Approaches for Better Insect Microbiome Research According to Next-Generation and Third-Generation Sequencing.

Microb Ecol 2021 Mar 11. Epub 2021 Mar 11.

State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China.

The microbial communities associated with insects play critical roles in many physiological functions such as digestion, nutrition, and defense. Meanwhile, with the development of sequencing technology, more and more studies begin to focus on broader biodiversity of insects and the corresponding mechanisms of insect microbial symbiosis, which need longer time collecting in the field. However, few studies have evaluated the effect of insect microbiome sample preservation approaches especially in different time durations or have assessed whether these approaches are appropriate for both next-generation sequencing (NGS) and third-generation sequencing (TGS) technologies. Here, we used Tessaratoma papillosa (Hemiptera: Tessaratomidae), an important litchi pest, as the model insect and adopted two sequencing technologies to evaluate the effect of four different preservation approaches (cetyltrimethylammonium bromide (CTAB), ethanol, air dried, and RNAlater). We found the samples treated by air dried method, which entomologists adopted for morphological observation and classical taxonomy, would get worse soon. RNAlater as the most expensive approaches for insect microbiome sample preservation did not suit for field works longer than 1 month. We recommended CTAB and ethanol as better preservatives in longer time field work for their effectiveness and low cost. Comparing with the full-length 16S rRNA gene sequenced by TGS, the V4 region of 16S rRNA gene sequenced by NGS has a lower resolution trait and may misestimate the composition of microbial communities. Our results provided recommendations for suitable preservation approaches applied to insect microbiome studies based on two sequencing technologies, which can help researchers properly preserve samples in field works.
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http://dx.doi.org/10.1007/s00248-021-01727-6DOI Listing
March 2021

Molecular detection and genetic diversity of Rickettsia spp. in pet dogs and their infesting ticks in Harbin, northeastern China.

BMC Vet Res 2021 Mar 7;17(1):113. Epub 2021 Mar 7.

Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, 528231, Foshan, Guangdong, China.

Background: Pet dogs are important companion animals that share the environment within households, and play an important role in local community life. In addition, pet dogs also are reservoirs of zoonotic agents, including Rickettsia spp., thus increasing the risk of rickettsial infections in humans. It's meaningful to investigate the epidemiology of rickettsial agents in pet dogs, and make contribute to the surveillance of rickettsioses in human in China.

Results: In this study, a total of 496 pet dogs' blood samples and 343 ticks infested in pet dogs were collected, and the presence and prevalence of Rickettsia were determined by amplifying the partial gltA and 17-kDa genes, with an overall positive rate of 8.1 % in blood samples and 14.0 % in tick samples. In addition, the rrs, gltA, groEL, and ompA genes of rickettsial were also recovered to determine the species of Rickettsia detected furtherly. Sequencing blast and phylogenetic analyses revealed the presence of three human pathogenic Rickettsia species (Rickettsia raoultii, Candidatus Rickettsia tarasevichiae and Rickettsia felis) in samples associated with pet dogs. Moreover, all the sequences of Rickettsia that we obtained presented close relationship with others available in GenBank, and Rickettsia raoultii was the most predominant Rickettsia species infected in pet dogs' blood samples or in tick samples.

Conclusions: This study provides the molecular epidemiology data about the Rickettsia spp. infection associated with pet dogs in urban areas of Harbin city. Three rickettisae species pathogenic to humans were identified from pet dogs' blood and the infested ticks in urban areas of Harbin city. Considering the intimate relationship between human and pets, these results indicate the potential transmission risk of human rickettisal infections from pet dogs through ectoparasites, and also highlighting that more attention should be paid to rickettsial infection in pet dogs and the infested ticks from the "One health" perspective.
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http://dx.doi.org/10.1186/s12917-021-02823-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7938463PMC
March 2021

Chthonobacter rhizosphaerae sp. nov., a bacterium isolated from rhizosphere soil of Citrus sinenesis.

Arch Microbiol 2021 Mar 2. Epub 2021 Mar 2.

China Tobacco Yunnan Industrial Co. Ltd., Kunming, 650231, People's Republic of China.

A Gram-staining negative, facultative anaerobic, motile and short rod-shaped bacterium, designated strain yh7-1, was isolated from rhizosphere soil of Citrus sinenesis collected from the garden of Citrus sinenesis in Ailao Mountain, south-west China. Cells grew at 15-45 °C, pH 5.0-9.0 and were able to tolerate up to 1% (w/v) NaCl on R2A medium. The respiratory lipoquinone was Q-10 and the major cellular fatty acids contained summed feature 8 (C ω7c or C ω6c) and C. Polar lipids in the cellular membrane were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and one unidentified aminophospholipid. The genomic DNA G+C content was 69.9 mol%. On basis of 16S rRNA gene sequence analysis, strain yh7-1 showed the highest similarities with Chthonobacter albigriseus KCTC 42450 (97.6%), Mongoliimonas terrestris KCTC 42635 (97.0%) and lower than 97.0% to other species. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain yh7-1 clustered with C. albigriseus KCTC 42450. The ANI values ranged between 78.1 and 82.7% for C. albigriseus KCTC 42450, M. terrestris KCTC 42635 and strain yh7-1, which were lower than the prokaryotic species delineation threshold of 95.0-96.0%. The digital DNA-DNA hybridization values between C. albigriseus KCTC 42450, M. terrestris KCTC 42635 and strain yh7-1 indicated that the new isolate represents a novel genomic species. According to the phenotypic and genotypic characteristics, strain yh7-1 should belong to the genus Chthonobacter, for which the name Chthonobacter rhizosphaerae sp. nov. (type strain yh7-1 = CGMCC 1.17236 = CCTCC AB 2019258 = KCTC 82185) is proposed.
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http://dx.doi.org/10.1007/s00203-021-02217-6DOI Listing
March 2021

Complex microbial communities inhabiting natural Cordyceps militaris and the habitat soil and their predicted functions.

Antonie Van Leeuwenhoek 2021 Apr 27;114(4):465-477. Epub 2021 Feb 27.

Yunnan Herbal Laboratory, Ecology and Environmental Sciences, Yunnan University, No. 2 Cuihu Lake North Road, Kunming, 650091, Yunnan, China.

Cordyceps militaris is a traditional Chinese medicinal food that is challenging to quality maintaining while mass cultivation. Many studies have found that abundant microbes inhabit Ophiocordyceps sinensis and perform important functions for their host. In this study, our objective was to reveal the microbial communities that inhabit C. militaris and analyze their potential functions. High-throughput sequencing of 16S rRNA and ITS genes was used to compare the diversity and composition of the bacterial and fungal communities associated with naturally occurring C. militaris collected from Yunnan Province, southwestern China. The diversity and richness of the microbial communities and the number of function genes of the bacteria were significantly higher in the habitat soil than in the fruiting body. The sclerotia and stromata samples shared the same microbiota and functions. The main bacterial phyla were Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria, and Ascomycota was the main fungal phylum. The growth-promoting bacteria Herbaspirillum and the plant probiotic Phyllobacterium, which may enhance C. militaris quality and facilitate its cultivation, were detected in the fruiting body samples. Genes related to metabolism were more abundant in the soil bacteria, while membrane transport genes were more abundant in the endophytic bacteria of C. militaris. Our study is the first to reveal the unexpectedly high diversity of the microbial communities and the bacterial functions inhabiting the natural C. militaris using high-throughput sequencing, and our results provide insights into mining the functions of microorganisms in the development and quality of C. militaris.
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http://dx.doi.org/10.1007/s10482-021-01534-6DOI Listing
April 2021

Revealing the salinity adaptation mechanism in halotolerant bacterium Egicoccus halophilus EGI 80432 by physiological analysis and comparative transcriptomics.

Appl Microbiol Biotechnol 2021 Mar 24;105(6):2497-2511. Epub 2021 Feb 24.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.

Egicoccus halophilus EGI 80432, a halotolerant bacterium isolated from a saline-alkaline soil, belongs to a member of the class Nitriliruptoria, which exhibits high adaptability to salt environments. At present, the detailed knowledge of the salinity adaptation strategies of Nitriliruptoria was limited except for one research by using comparative genomics analysis. Here, we investigated the salinity adaptation mechanism of E. halophilus EGI 80432 by comparative physiological and transcriptomic analyses. The results of physiological analyses showed that trehalose and glutamate were accumulated by salt stress and showed the maximum at moderate salinity condition. Furthermore, the contents of histidine, threonine, proline, and ectoine were increased with increasing salt concentration. We found that both 0% and 9% NaCl conditions resulted in increased expressions of genes involved in carbohydrate and energy metabolisms, but negatively affected the Na efflux, iron, and molybdate transport. Moreover, the high salt condition led to enhancement of transcription of genes required for the synthesis of compatible solutes, e.g., glutamate, histidine, threonine, proline, and ectoine, which agree with the results of physiological analyses. The above results revealed that E. halophilus EGI 80432 increased inorganic ions uptake and accumulated trehalose and glutamate in response to moderate salinity condition, while the salinity adaptation strategy was changed from a "salt-in-cytoplasm" strategy to a "compatible solute" strategy under high salinity condition. The findings in this study would promote further studies in salt tolerance molecular mechanism of Nitriliruptoria and provide a theoretical support for E. halophilus EGI 80432's application in ecological restoration.Key Points• Salt stress affected gene expressions responsible for carbohydrate and energy metabolisms of E. halophilus EGI 8042.• E. halophilus EGI 80432 significantly accumulated compatible solutes under salt stress.• E. halophilus EGI 80432 adopted a "compatible solute" strategy to withstand high salt stress.
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http://dx.doi.org/10.1007/s00253-021-11190-5DOI Listing
March 2021

Thermaurantiacus tibetensis gen. nov., sp. nov., a novel moderately thermophilic bacterium isolated from hot spring microbial mat in Tibet.

Antonie Van Leeuwenhoek 2021 Apr 23;114(4):445-455. Epub 2021 Feb 23.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.

Two bacterial strains SYSU G02173 and SYSU G03142 were isolated from hot springs in Tibet, China. Based on the results of nearly full-length 16S rRNA gene sequences and phylogenetic analyses, strains SYSU G02173 and SYSU G03142 were assigned to the family Sphingosinicellaceae, and were closest to Sandaracinobacter sibiricus RB16-17 (96.04% and 96.12% similarity, respectively). Cells of the both new strains were observed to be motile rod-shape, Gram-staining negative. Growth occurred at pH 6-8 (optimal: pH 7.0) and 37-55 °C (optimal: 45 °C) with 0-1.0% (w/v) NaCl in T4 broth. The cells were found to be positive for oxidase and catalase activities. The major respiratory ubiquinone was Q-8. The major fatty acids were identified as summed feature 8 (C ω7c and/or C ω6c), C, C 2-OH. The major polar lipids were found to consist of sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified phospholipid, one unidentified glycolipid, three unidentified aminolipids and two unidentified polar lipids. The DNA G + C contents of strains SYSU G02173 and SYSU G03142 were 71.8%. The average nucleotide identity (ANI) value between strain SYSU G02173 and SYSU G03142 was 99.98%. The amino acid identity (AAI) values between them and their closely related species were below 66.14%. The isolates are characterized by aerobic growth, a yellow endocellular pigment and a higher optimum growth temperature. The results showed that strains SYSU G02173 and SYSU G03142 represent a novel species of a novel genus in the family Sphingomonadaceae, and thus the name Thermaurantiacus tibetensis (type strain SYSU G02173 = KCTC 72052 = CGMCC 1.16680) is proposed.
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http://dx.doi.org/10.1007/s10482-021-01530-wDOI Listing
April 2021

Siccirubricoccus phaeus sp. nov., isolated from oil reservoir water and emended description of the genus Siccirubricoccus.

Antonie Van Leeuwenhoek 2021 Apr 6;114(4):355-364. Epub 2021 Feb 6.

State Key Laboratory of Agrobiotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193, People's Republic of China.

A Gram-staining-negative, non-motile, aerobic bacterium, designated 1-3, was isolated from oil reservoir water collected from Liaohe oilfield, north-east of China. Growth was observed at 15-40 °C (optimum 37 °C) and pH 6-10 (optimum 7). The strain can grow under nitrogen-limiting condition. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate was most closely related to Siccirubricoccus deserti SYSU D8009 (96.7%), followed by Paracraurococcus ruber NS89 (95.7%) and Belnapia rosea CPCC 100156 (94.9%). Genome sequencing revealed a genome size of 6.43 Mbp and a G+C content of 71.3 mol%. The average nucleotide identity values and digital DNA-DNA hybridization between 1-3 and the reference strains were all below the cut-off level (95-96% and 70%, respectively) for species delineation. The strain possessed the cytochrome P450 enzyme, which has the potential to degrade oil. The respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (C ω7c/C ω6c, 38.8%), C (25.6%) and C cyclo ω8c (22.5%). The polar lipids of strain 1-3 comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and three unidentified aminolipids. Based on the genotypic and phenotypic characteristics, strain 1-3 represents a novel species of genus Siccirubricoccus, for which the name Siccirubricoccus phaeus sp. nov. is proposed. The type strain of Siccirubricoccus phaeus is 1-3 (= CGMCC 1.16799 = LMG 31398).
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http://dx.doi.org/10.1007/s10482-021-01516-8DOI Listing
April 2021

Neobacillus sedimentimangrovi sp. nov., a Thermophilic Bacterium Isolated from Mangrove Sediment.

Curr Microbiol 2021 Mar 4;78(3):1039-1044. Epub 2021 Feb 4.

Fujian Agricultural and Forestry University, Fuzhou, 350002, Fujian, China.

Two Gram-stain positive, rod-shaped, endospore-forming, aerobic, thermophilic strains, designated FJAT-2464 and FJAT-52740, were isolated from the sediment collected from Zhangjiang Estuary Mangrove National Nature Reserve in Fujian Province, China. The 16S rRNA gene sequence similarity between strains FJAT-2464 and FJAT-52740 was 100%. The result suggests that strains FJAT-2464 and FJAT-52740 belong to the same genome species, hence only FJAT-2464 was considered for further analysis. Strain FJAT-2464 showed the highest 16S rRNA gene sequence similarities to the type strains of Neobacillus thermocopriae SgZ-7 (99.9%), Neobacillus cucumis AP-6 (97.6%) and Neobacillus drentensis LMG 21831 (97.5%). Growth was observed at 25-65 °C (optimum 60 °C), pH 7.0-8.0 (optimum 8.0) with NaCl tolerance up to 1.0% (w/v) (optimum without NaCl %). The cell-wall peptidoglycan contained meso-diaminopimelic acid and MK-7 was the only respiratory quinone. The major fatty acids were iso-C and anteiso-C. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified aminophospholipid and unidentified lipids. The average nucleotide identity and digital DNA-DNA hybridization values between strain FJAT-2464 and the most closely related strain N. thermocopriae SgZ-7 was below the threshold value for species delineation. Based on the above results, strain FJAT-2464 represents a novel species of the genus Neobacillus, for which the name Neobacillus sedimentimangrovi sp. nov. is proposed. The type strain is FJAT-2464 (= MCCC 1K04406 = KCTC 43264).
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http://dx.doi.org/10.1007/s00284-021-02360-9DOI Listing
March 2021

Monitoring the decolourisation efficacy of advanced membrane fabricated phytosilica nanoparticles in textile effluent water treatment.

Chemosphere 2021 Jan 18;273:129681. Epub 2021 Jan 18.

Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.

Silica nanoparticles are generally mesoporous that are predominant in the sand and rocks. Silica nanoparticles have a wide range of applications in various fields such as medicine, waste management, effluent treatment and electronics. The present work has explored the synthesis of silica nanoparticles through acid and alkaline leaching method from Pedalium murex which is a common weed that is found in southern parts of Tamil Nadu. Silica nanoparticles (SiNps) and its functional groups were confirmed by EDX and FTIR analysis with their respective energy dispersion levels and wavenumbers. Size, shape and morphological features of SiNps were analysed by PSA, TEM and SAED analysis. Synthesised and characterized nanosilica was crosslinked over nylon-66 and cellulose nitrate membranes and were confirmed by FTIR analysis for their crosslinking with SiNps. Water retention activity of the crosslinked and non crosslinked membranes was analysed by contact angle measurement to ensure the receptability of the membranes to remove contaminants by the adsorption. The decolourisation efficiency of the crosslinked nylon 66 membrane was found as a potential source for the treatment with 65.5% colour reduction when compared with other membranes. A slight reduction of solid profiles and COD ranges were achieved for crosslinked membranes than non crosslinked membranes.
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http://dx.doi.org/10.1016/j.chemosphere.2021.129681DOI Listing
January 2021

Genomic Insights of " Nitrosocaldaceae" Based on Nine New Metagenome-Assembled Genomes, Including " Nitrosothermus" Gen Nov. and Two New Species of " Nitrosocaldus".

Front Microbiol 2020 8;11:608832. Epub 2021 Jan 8.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China.

" Nitrosocaldaceae" are globally distributed in neutral or slightly alkaline hot springs and geothermally heated soils. Despite their essential role in the nitrogen cycle in high-temperature ecosystems, they remain poorly understood because they have never been isolated in pure culture, and very few genomes are available. In the present study, a metagenomics approach was employed to obtain " Nitrosocaldaceae" metagenomic-assembled genomes (MAGs) from hot spring samples collected from India and China. Phylogenomic analysis placed these MAGs within " Nitrosocaldaceae." Average nucleotide identity and average amino acid identity analysis suggested the new MAGs represent two novel species of " Nitrosocaldus" and a novel genus, herein proposed as " Nitrosothermus." Key genes responsible for chemolithotrophic ammonia oxidation and a thaumarchaeal 3HP/4HB cycle were detected in all MAGs. Furthermore, genes coding for urea degradation were only present in " Nitrosocaldus," while biosynthesis of the vitamins, biotin, cobalamin, and riboflavin were detected in almost all MAGs. Comparison of ". Nitrosocaldales/Nitrosocaldaceae" with other AOA revealed 526 specific orthogroups. This included genes related to thermal adaptation (cyclic 2,3-diphosphoglycerate, and S-adenosylmethionine decarboxylase), indicating their importance for life at high temperature. In addition, these MAGs acquired genes from members from archaea (Crenarchaeota) and bacteria (Firmicutes), mainly involved in metabolism and stress responses, which might play a role to allow this group to adapt to thermal habitats.
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http://dx.doi.org/10.3389/fmicb.2020.608832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7819960PMC
January 2021

Zafaria cholistanensis gen. nov. sp. nov., a moderately thermotolerant and halotolerant actinobacterium isolated from Cholistan desert soil of Pakistan.

Arch Microbiol 2021 Jan 18. Epub 2021 Jan 18.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences,, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.

A Gram-staining positive, non-spore forming, non-pigmented and non-motile bacterium, designated strain NCCP-1664, was isolated from Cholistan desert, Pakistan. Cells of strain NCCP-1664 were strictly aerobic, catalase positive and oxidase negative with a rod to coccus growth cycle and can grow at pH 6.0-9.0 (optimum pH 7-8) at 28-45 °C (optimum 37 °C) and could tolerate 0-16% NaCl (optimum 2%). Phylogenetic analyses based on 16S rRNA gene sequence revealed that strain NCCP-1664 belongs to the family Micrococcaceae and was related to members of the genus Arthrobacter having highest sequence similarities with Arthrobacter ginkgonis (98.9%), A. halodurans (97.7%) and A. oryzae (97.1%) and less than 97% with other related taxa. DNA-DNA relatedness values of strain NCCP-1664 with above mentioned type strains were found to be less than 54%, whereas digital DDH and average nucleotide identity (ANI) values with A. oryzae were 20.9 and of 74.3%, respectively. DNA G + C content of strain NCCP-1664 was 70.0 mol%. Chemotaxonomic data of strain NCCP-1664 showed the peptidoglycan type as A3α L-Lys-L -Ala; menaquinones as MK-9(H) (67%), MK-8(H) (32%) and MK-7(H) (1%), major fatty acids as anteiso -C (51.2%), anteiso-C (9.6%) and Cω9c (6.9%) and polar lipids profile comprising of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, digalactosyldiacylglycerol, small amounts of monogalactosyldiacylglycerol, trimannosyldiacylglycerol and three unidentified lipids. The phylogenomic analyses along with chemotaxonomic data, physiological, biochemical characteristics allowed to describe it as representative of a novel genus, for which the name Zafaria cholistanensis gen. nov. sp. nov. is proposed with the type strain NCCP-1664 (= DSM 29936 = KCTC 39549).
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http://dx.doi.org/10.1007/s00203-020-02176-4DOI Listing
January 2021

[Research Advances in the Diagnostic Value of Rapid On-site Evaluation in Endobronchial Ultrasound-guided Transbronchial Needle Aspiration for Lung Cancer].

Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2020 Dec;42(6):820-824

Department of Respiratory,Lanzhou University Second Hospital,Lanzhou 730000,China.

Rapid on-site evaluation(ROSE),an auxiliary sampling quality evaluation technology,can be used to evaluate the adequacy and diagnostic category of samples,judge the histological type of lung cancer,and optimize the gene type of lung cancer.Applying ROSE to endobronchial ultrasound-guided transbronchial needle aspiration of suspected lung cancer can improve the puncture success rate and diagnostic rate and reduce complications and puncture attempts.Rose performed via remote cytopathology technology or by trained respiratory specialists may become the future trends.
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http://dx.doi.org/10.3881/j.issn.1000-503X.12183DOI Listing
December 2020

gen. nov., sp. nov., a member of the family , isolated from a saline and alkaline lake sediment.

Int J Syst Evol Microbiol 2021 Feb;71(2)

State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, PR China.

A non-motile, Gram-staining negative, catalase- and oxidase-positive, crescent-rod shaped bacterium, designated strain CUG 91308, was isolated from a sediment sample of Qinghai Lake, Qinghai Province, China. Colonies on OSM agar were round, smooth, flat and pinkish-orange in colour. Strain CUG 91308 could grow at 15-37 °C, pH 6-12 and in the presence of up to 7.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CUG 91308 belonged to the family and formed a clade with the genus in the phylogenetic tree, but separated from any species of the known genera within the family. The genomic DNA G+C content is about 42.1 %. The predominant fatty acids (>10 %) were iso-C (21.1 %), summed feature 3 (C  7c / C  6c / iso-C 2OH) (14.3 %), iso-C 3OH (12.3 %) and summed feature 9 (iso-C  9c / C 10-methyl) (10.6 %). The polar lipids of strain CUG 91308 were phosphatidylethanolamine (PE) and four unidentified polar lipids. Strain CUG 91308 contained MK-7 as the major respiratory quinone. On the basis of phenotypic, genotypic and phylogenetic data, strain CUG 91308 represents a novel species of a novel genus in the family , for which the name gen. nov., sp. nov. is proposed. The type strain of the proposed new isolate is CUG 91308 (=KCTC 62636=CGMCC 1.13593).
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http://dx.doi.org/10.1099/ijsem.0.004621DOI Listing
February 2021

Description of Salinimonas profundi sp. nov., a deep-sea bacterium harboring a transposon Tn6333.

Antonie Van Leeuwenhoek 2021 Jan 3;114(1):69-81. Epub 2021 Jan 3.

Institute of Marine Biology, College of Oceanography, Hohai University, Nanjing, People's Republic of China.

A Gram-staining-negative bacterium, strain HHU 13199, was isolated from a marine sediment sample collected from South China Sea (119°19.896'E, 19°41.569'N) at a depth of 2918 m. The 16S rRNA gene sequence analysis indicated that strain HHU 13199 represents a member of the genus Salinimonas with the highest sequence similarity (99.8%) to the type strain S. iocasae KX18D6. However, the average nucleotide identity values and digital DNA-DNA hybridization between strain HHU 13199 and closely related members of the genus Salinimonas were all below the cut-off level (95-96 % and 70%, respectively) for species delineation. This strain grew with sea salt of 0.5-18% (w/v) (optimum, 2-5%), but no growth observed when using NaCl instead. The major fatty acids are C, summed feature 3 (Cω7c and/or Cω6c), and summed feature 8 (Cω7c and/or Cω6c). The predominant isoprenoid quinone is ubiquinone-8. The polar lipids mainly consist of phosphatidylethanolamine, and phosphatidylglycerol. Genomic characterization revealed that strain HHU 13199 harbors a distinct type I-F CRISPR-Cas system and plenty of genes associated with heavy metal resistance, including a transposon (Tn6333) conferring mercury resistance. In addition, a phylogenetic tree based on the bac120 core genes suggested that the genus Salinimonas should be a subclade within Alteromonas. On the basis of the phenotypic, phylogenetic and chemotaxonomic characterizations, strain HHU 13199 represents a novel species of the genus Salinimonas, for which the name Salinimonas profundi sp. nov. is proposed. The type strain is HHU 13199 (= KCTC 72837 = MCCC 1K04127).
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http://dx.doi.org/10.1007/s10482-020-01501-7DOI Listing
January 2021

Nesterenkonia haasae sp. nov., an alkaliphilic actinobacterium isolated from a degraded pasture in Songnen Plain.

Arch Microbiol 2021 Apr 26;203(3):959-966. Epub 2020 Oct 26.

State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.

An alkaliphilic actinobacterial strain, designated Hz 6-5, was isolated from saline-alkaline soil from Songnen Plain in north-eastern China. The isolate formed light yellow-colored colonies and its cells were Gram-staining positive, non-motile, and non-spore-forming short rods. The strain was aerobic with optimal growth at 33 °C, pH 9.0, and in the presence of 0.5% (w/v) NaCl or 3% (w/v) KCl. It was catalase-positive and oxidase-negative. The isolate had highest 16S rRNA gene sequence similarities to the type strains of the species Nesternkonia natronophila M8 (98.2%), N. salmonea GY074 (98.1%), and N. sphaerica GY239 (97.4%), and the isolate formed a subclade with the type strains of these species in the neighbor-joining tree based on the 16S rRNA gene sequences. The phylogenetic tree based on the phylogenomic analysis also showed the same results. The DNA‒DNA relatedness (DDH) values of isolate Hz 6-5 with N. natronophila M8, N. halophila DSM 16378, and N. halobia CGMCC 1.2323 were 21.2%, 36.5%, and 32.0%, respectively. The characteristic diamino acid of strain Hz 6-5 was found to be lysine. The respiratory quinones were MK-9, MK-8, MK-7(H), MK-7(H) and MK-7 and the major cellular fatty acids (> 10%) were anteiso-C, anteiso-C and iso-C. The polar lipids detected for strain Hz 6-5 were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, an unidentified glycolipid, and two unidentified phospholipids. The DNA G + C content of isolate Hz 6-5 was 60.8%. Based on the results of phylogenetic analysis supported by morphological, physiological, chemotaxonomic, and other differentiating phenotypic evidence, strain Hz 6-5 is considered to represent a novel species of the genus Nesterenkonia, for which the name Nesterenkonia haasae sp. nov. is proposed. The type strain is Hz 6-5 (=CPCC 205100=NBRC 113521).
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http://dx.doi.org/10.1007/s00203-020-02073-wDOI Listing
April 2021

Bacillus alkalicellulosilyticus sp. nov., isolated from extremely alkaline bauxite residue (red mud) site.

Arch Microbiol 2021 Mar 12;203(2):719-723. Epub 2020 Oct 12.

State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China.

A Gram-stain-negative, rod-shaped, facultatively anaerobic, motile and spore-forming strain designated FJAT-44921 was isolated from red mud collected from Chiping County, Shandong Province, China. The 16S rRNA gene sequence result showed that strain FJAT-44921 shared a low sequence identity (96.6%) with the members of the genus Bacillus. Growth was observed at pH 8.0-10.0 (optimum pH 9.0), 10-40 °C (optimum 20-25 °C) with 0-8% (v/w %) NaCl (optimum 4-6 v/w %). FJAT-44921 consists of MK-7 as the isoprenoid quinone and meso-2,6-diaminopimelic acid as the cell-wall diamino acid. The predominant fatty acids were anteiso-C, iso-C, C, and anteiso-C. The polar lipids were diphosphatidylglycerol, phosphatidyl glycerol, phosphatidylmethylethanolamine, unidentified phospholipid, and unidentified aminophospholipid. The genomic DNA G + C content was 37.3 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between FJAT-44921 and other closely related Bacillus members were lower than the recognized threshold values of ANI (95-96%) and dDDH (70%) recommended as the criterion for interspecies identity. The type strain is FJAT-44921 (=CCTCC AB 2016196 =DSM 104630).
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http://dx.doi.org/10.1007/s00203-020-02063-yDOI Listing
March 2021

Photocatalytic reduction and anti-bacterial activity of biosynthesized silver nanoparticles against multi drug resistant Staphylococcus saprophyticus BDUMS 5 (MN310601).

Mater Sci Eng C Mater Biol Appl 2020 Sep 28;114:111024. Epub 2020 Apr 28.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China; State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China. Electronic address:

In this study, silver nanoparticles (Ag NPs) was eco-friendly synthesized using purified flavonoid rich content of Morinda citrifolia (M. citrifolia) extract. The synthesized Ag NPs was exhibited at 420 nm in UV-spectrometer, and surface morphology with available chemical composition, shape and size of the Ag NPs were confirmed by X-ray diffraction (XRD) variation, scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and transmission electron microscope (TEM). In addition, the excellent phytochemicals and anti-oxidant activity of the Ag NPs were confirmed by total anti-oxidant and DPPH free radical scavenging assays. Further, the concentration dependent inhibition of synthesized Ag NPs against biofilm forming Staphylococcus aureus (S. aureus) was confirmed by minimum inhibition concentration (MIC). The growth cells were arrested in the log phase of the culture and detected by flow cytometry analysis. In addition, the bacterial viability, exopolysaccharide degradation, intracellular membrane damage, matured biofilm inhibition, architectural damage and morphological alteration were confirmed by confocal laser scanning electron microscope (CLSM) and SEM. Furthermore, the synthesized Ag NPs reacted with methylene blue (MB) dye molecules has 100% degradation at an irradiation time of 140 min. Conclusively, the eco-friendly synthesized Ag NPs has excellent anti-oxidant, anti-bacterial through intracellular membrane damage, cell cycle arrest and methylene blue dye removal.
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http://dx.doi.org/10.1016/j.msec.2020.111024DOI Listing
September 2020

gen. nov., sp. nov., a novel cellulose- and xylan-degrading member of the family isolated from a hot spring.

Int J Syst Evol Microbiol 2020 Nov;70(11):5717-5724

State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China.

Two anaerobic bacteria, designated strains SYSU GA16112 and SYSU GA16107, were isolated from a hot spring in Tengchong County, Yunnan Province, south-west PR China. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SYSU GA16112 and SYSU GA16107 belong to the family . Cells of strains SYSU GA16112 and SYSU GA16107 were Gram-stain-negative, rod-shaped and non-motile. The major fatty acids (>10 %) of strains SYSU GA16112 and SYSU GA16107 were identified as anteiso-C and anteiso-C 3OH. The polar lipid profile of strain SYSU GA16112 was found to consist of phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified phosphoglycolipids, two unidentified aminolipids and one unidentified polar lipid, while that of strain SYSU GA16107 consisted of phosphatidylethanolamine, two unidentified polar lipids, three unidentified aminophospholipids, two unidentified phosphoglycolipids and one unidentified aminolipid. The genomic DNA G+C contents of strains SYSU GA16112 and SYSU GA16107 were determined to be 41.90 and 41.89 %, respectively, and the average nucleotide identity value between them was 99.99 %. Based on their morphological and physiological properties, and results of phylogenetic analyses, strains SYSU GA16112 and SYSU GA16107 are considered to represent a novel species of a novel genus, for which the name gen. nov., sp. nov. (type strain SYSU GA16112=CGMCC 1.5281=KCTC 15753) is proposed.
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http://dx.doi.org/10.1099/ijsem.0.004469DOI Listing
November 2020

Correction to: Description of Paenibacillus yunnanensis sp. nov., Isolated from a Tepid Spring.

Curr Microbiol 2020 Dec;77(12):4192

State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China.

It was brought to our attention that the proposed name Paenibacillus yunnanensis is an illegitimate homonym of Paenibacillus yunnanensis Niu et al. 2015. We therefore propose changing the name of the newly proposed species to Paenibacillus tengchongensis as follows.
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http://dx.doi.org/10.1007/s00284-020-02211-zDOI Listing
December 2020

Insulin-delivery methods for children and adolescents with type 1 diabetes.

Ther Adv Endocrinol Metab 2020 8;11:2042018820906016. Epub 2020 May 8.

Hunan Key Laboratory of Biological Nanomaterials and Devices, School of Life Sciences and Chemistry, Hunan University of Technology, Hunan, Zhuzhou 412007, PR China.

Efforts directed toward restoring normal metabolic levels by mimicking the physiological insulin secretion, thereby ensuring safety, efficacy, minimal invasiveness and conveniences, are of great significance in the management of type 1 diabetes among children and adolescents. Regardless of the various technologies being discovered in addressing invasiveness and enhancing medication adherence in the management of type 1 diabetes, yet limited success had been observed among children and adolescents. The multiple daily subcutaneous insulin injections route using vial and syringe, and occasionally insulin pens, remain the most predictable route for insulin administration among children and adolescents. However, this route has been associated with compromised patient compliance, fear of injections and unacceptability, resulting in poor glycemic control, which promote the demand for alternative routes of insulin administration. Alternative routes for delivering insulin are being investigated in children and adolescents with type 1 diabetes; these include the hybrid closed-loop 'artificial pancreas' system, oral, inhalation, intranasal routes, and others. This review article explores the current advances in insulin-delivery methods that address the needs of children and adolescents in the treatment of type 1 diabetes.
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http://dx.doi.org/10.1177/2042018820906016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466897PMC
May 2020

Gene expression abundance dictated exopolysaccharide modification in Rhizobium radiobacter SZ4S7S14 as the cell's response to salt stress.

Int J Biol Macromol 2020 Dec 12;164:4339-4347. Epub 2020 Sep 12.

Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, PR China; State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Xinggang West Road, Guangzhou 510275, PR China.

A molecular and metabolic behaviour of EPS-producing and salt-tolerant bacterium Rhizobium radiobacter SZ4S7S14 along with its practical application in salt-stress was investigated. The research target was identification and expression profiles of a large EPS biosynthesis gene cluster, possible structural modification of EPS under salt-stress effect and analysis of the gene(s) relative expression and structural modification correlation. As expected, transposons insertions were identified within or near the coding regions of exoK and exoM, previously known large gene cluster that is required for EPS I synthesis. Different expression levels of exoK and exoM in different salt-stress models resulted in structural modification of EPS, which was seen basically in monomers molar ratio. As a result of downregulation of the genes the strain produced EPS samples with monomers ratio: (1) Glu:Man:Gal:Xyl:Ara:Rha:Rib = 31.21:3.02:2.77:1:0.91:0.64:0.41 (in 0.25% NaCl); (2) Glu:Man:Gal:Xyl:Ara:Rha:Rib = 7.65:1:0.69:0.22:0.2:0.16:0.1 (in 0.5% NaCl); (3) Glu:Man:Gal:Ara:Xyl:Rha:Rib = 9.39:1.89:1:0.58:0.52:0.46:0.26 (in 1% NaCl); and (4) Glu:Man:Ara:Xyl:Rib:Gal = 7.9:2:2:1.58:1.1:1 (in 2.0% NaCl), whereas in control (without NaCl): Glc:Man:Gal:Xyl:Ara:Rha:Rib = 11.66:1:0.90:0.37:0.37:0.15:0.14. It was found that, salt-stress not only leads to downregulation of a large EPS biosynthesis gene cluster, including exoK and exoM genes, but also impacting on their relative expression degree, re-groups of the monomers within the EPS matrix and dictates molar ratio of the monosaccharides in the final metabolite.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.09.038DOI Listing
December 2020

Anti-carbapenamase activity of essential oil against isolated carbapenem resistant (MN396685).

Saudi J Biol Sci 2020 Sep 30;27(9):2269-2279. Epub 2020 Jun 30.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.

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http://dx.doi.org/10.1016/j.sjbs.2020.06.044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451749PMC
September 2020

Enhanced anti-cancer activity of chitosan loaded Morinda citrifolia essential oil against A549 human lung cancer cells.

Int J Biol Macromol 2020 Dec 24;164:4010-4021. Epub 2020 Aug 24.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China; State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China. Electronic address:

In the present study, the chemical composition of Morinda citrifolia essential oils was determined by gas chromatography-mass spectrometry and was found to contain several anti-cancer compounds including L-scopoletin, nordamnacanthal, β-morindone, α-copaene, 9-H-pyrido[3,4-b]indole, β-thujene and terpinolene. The physico-chemical characterization of chitosan, chitosan nanoparticles and Morinda citrifolia essential oils loaded chitosan nanoparticles combination was carried out by Fourier transform infrared spectroscopy, powder X-ray diffraction and dynamic light scattering coupled with zeta potential. The morphological observation obtained by scanning electron microscopy and transmission electron microscopy provided clear indication that the immobile chitosan polymer formed a coating onto the Morinda citrifolia essential oils surface. The cytotoxic effect of Morinda citrifolia essential oils loaded chitosan nanoparticles against A549 cells were investigated, resulting in 54% inhibition at 40 μg/ml. Information about in vitro morphological modification, nucleus damages, ROS generation and cell cycle arrest was obtained by fluorescence microscopy and flow cytometer analysis. The toxicity evaluation against human red blood cells suggested that the Morinda citrifolia essential oils loaded chitosan nanoparticles possess minimum cytotoxicity. Altogether, the present study suggests that these Morinda citrifolia essential oils loaded chitosan nanoparticles are valuable biomaterials owing to their ability to fight against A549 cancer cells.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.08.169DOI Listing
December 2020

Isolation of Clostridium from Yunnan-Tibet hot springs and description of Clostridium thermarum sp. nov. with lignocellulosic ethanol production.

Syst Appl Microbiol 2020 Sep 21;43(5):126104. Epub 2020 Jun 21.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address:

Lignocellulose is considered a major source of renewable energy that serve as an alternative to the fossil fuels. Members of the genus Clostridium are some of the many microorganisms that have the ability to degrade lignocellulose efficiently to sugar, which can be further converted to biofuel. In this study, we isolated twelve Clostridium strains from hot spring samples of Yunnan and Tibet, of which isolates SYSU GA15002 and SYSU GA17076 showed low 16S rRNA gene sequence identity profiles to any of the validly named Clostridium strains (<94.0%). Studies using a polyphasic taxonomy approach concluded that the two isolates represent one novel species of the genus Clostridium, for which we propose the name Clostridium thermarum sp. nov., with SYSU GA15002 as the type strain of the species. Isolate SYSU GA15002 has an optimum growth temperature at 45°C. Fermentation of the substrates cellobiose, cellulose, xylan and untreated straw powder by this strain results in the production of ethanol, along with acetate and formate. The complete pathways for the conversion of cellulose and xylan to ethanol is also predicted from the genome of isolate SYSU GA15002, which revealed a single step conversion of lignocellulosic biomass through consolidated bioprocessing. This paper is a comprehensive study encompassing isolation, polyphasic taxonomy, lignocellulose biodegradation and the genomic information of Clostridium in Yunnan-Tibet hot springs.
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http://dx.doi.org/10.1016/j.syapm.2020.126104DOI Listing
September 2020

Sphingomonas hominis sp. nov., isolated from hair of a 21-year-old girl.

Antonie Van Leeuwenhoek 2020 Oct 11;113(10):1523-1530. Epub 2020 Aug 11.

State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.

A Gram-stain-negative, aerobic, motile strain, HHU CXW, was isolated from hair of a healthy 21-year-old female student of Hohai University, Nanjing, China. The 16S rRNA gene sequence analysis indicated that HHU CXW represents a member of the genus Sphingomonas with the highest sequence similarity (97.6%) to the type strain S. aquatilis JSS7. HHU CXW grew at 4-35 °C and pH 6-8, with optimum growth at 28 °C and pH 7. Tolerance to NaCl was up to 2% (w/v) with optimum growth in 0.5-1.0% NaCl. The major fatty acids were C, Cω6c, Cω7c11-methyl, summed feature 3 (Cω7c and/or Cω6c), and summed feature 8 (Cω7c and/or Cω6c). The predominant isoprenoid quinone was ubiquinone-10. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), sphingoglycolipid (SGL), phosphatidylinositol mannosides (PIM), and an unidentified glycolipid (GL). The DNA G + C content was 67.1%. The average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) between HHU CXW and closely related members of the genus Sphingomonas were all below the cut-off level (95-96% and 70%, respectively) for species delineation. On the basis of the phenotypic, phylogenetic and chemotaxonomic characterizations, HHU CXW represents a novel species of the genus Sphingomonas, for which the name Sphingomonas hominis sp. nov. is proposed. The type strain is HHU CXW (= KCTC 72946 = CGMCC 1.17504 = MCCC 1K04223).
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http://dx.doi.org/10.1007/s10482-020-01460-zDOI Listing
October 2020

Characterization of a Cu, SDS, alcohol and glucose tolerant GH1 β-glucosidase from Bacillus sp. CGMCC 1.16541.

Antonie Van Leeuwenhoek 2020 Oct 3;113(10):1467-1477. Epub 2020 Aug 3.

College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China.

A β-glucosidase gene (bsbgl1a) from Bacillus sp. CGMCC 1.16541 was expressed in Escherichia coli BL21 and subsequently characterized. The amino acid sequence shared 83.64% identity with β-glucosidase (WP_066390903.1) from Fictibacillus phosphorivorans. The recombinant β-glucosidase (BsBgl1A) had a molecular weight of 52.2 kDa and could hydrolyze cellobiose, cellotriose, cellotetrose, p-nitrophenyl-β-D-glucopyranoside (pNPG), and p-nitrophenyl-β-D-xylopyranoside (pNPX). Optimal activity for BsBgl1A was recorded at 45 °C with a pH between 5.6 and 7.6, and 100% of its activity was maintained after a 24 h incubation between pH 4 and 9. Kinetic characterization revealed an enzymatic turnover (Kcat) of 616 ± 2 s (with cellobiose) and 3.5 ± 0.1 s (with p-nitrophenyl-β-D-glucopyranoside). Interestingly, the recombinant enzyme showed cupric ion (Cu), sodium dodecyl sulfate (SDS) and alcohol tolerance at 10 mM for Cu and 10% for both SDS and alcohol. Additionally, BsBgl1A had high tolerance for glucose (Ki = 2095 mM), which is an extremely desirable feature for industrial applications. Following the addition of BsBgl1A (0.05 mg/ml) to a commercial cellulase reaction system, glucose yields from sugarcane bagasse increased 100% after 1 day at 45 °C. This work identifies a Cu, SDS, alcohol, and glucose tolerant GH1 β-glucosidase with potential applications in the hydrolysis of cellulose for the bioenergy industry.
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http://dx.doi.org/10.1007/s10482-020-01455-wDOI Listing
October 2020