Publications by authors named "Yongqiang Tian"

77 Publications

Combining multiple Bacillus spp. with fish protein hydrolysates mitigates root rot (Fusarium solani) and improves cucumber seedlings growth and substrate nutrients.

J Appl Microbiol 2021 Nov 26. Epub 2021 Nov 26.

College of Agriculture, Ningxia University, Helanshan xilu No.489, Yinchuan, 750021, China.

Aims: The effect of Bacillus strains combined with fish protein hydrolysates (FPHs) on cucumber root rot disease, seedlings growth and substrate nutrients was investigated.

Methods And Results: We isolated three strains capable of mitigating cucumber root rot disease, XY-1 and XY-13 strains were identified as B. amyloliquefaciens, and XY-53 strain as B. subtilis. In the absence of bacteria, The 200×dilution (5ml l ) of FPHs was the optimum concentration for improving cucumber seedlings growth. In vivo antibiosis tests showed that combined bacteria alongside FPHs inhibited the pathogen growth by 85%~90%, higher than individual bacteria. The FPHs combined either with XY-1 and XY-53 strains or with XY-13 and XY-53 strains promoted seedlings growth under infection, while FPHs combined with a mixture of XY-1, XY-13 and XY-53 strains showed the highest total phosphorus and organic matter content in substrate. Moreover, FPHs combined with XY-53 strain increased urease activity, while combined either with XY-13 and XY-53 strains or with XY-1, XY-13 and XY-53 strains increased sucrase activity under infection.

Conclusions: FPHs combined with B. amyloliquefaciens and B. subtilis had great potential to suppress root rot and promote cucumber seedlings growth and increase substrate nutrients content.

Significance And Impact Of The Study: Co-inoculation of B. amyloliquefaciens and B. subtilis with addition FPHs is a good strategy for maintaining healthy crops.
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http://dx.doi.org/10.1111/jam.15386DOI Listing
November 2021

Exoproduction and biochemical characterization of a novel serine protease from L9 with hide-dehairing activity.

J Microbiol Biotechnol 2021 Nov 20;32(1). Epub 2021 Nov 20.

Key Laboratory of Leather Chemistry and Engineering, Ministry of Education and College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, P.R China.

This study is the first report on production and characterization of the enzyme from an species. A 4.2-fold increase in the extracellular protease (called L9T) production from L9 was achieved through one factor at-a-time approach and response surface methodological optimization. L9 protease exhibited a unique protein band with a mass of 25.9 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This novel protease was active over a range of pH (4-13), temperatures (30-80 oC) and salt concentrations (0-220 g/L), with the maximal activity observed at pH 7, 70 oC and 20 g/L NaCl. Proteolytic activity was upgraded in the presence of Ag+, Ca2+ and Sr2+, but was totally suppressed by 5 mM phenylmethylsulfonyl fluoride which suggests that this enzyme belongs to the serine protease family. L9 protease was resistant to certain common organic solvents and surfactants; particularly, 5 mM Tween 20 and Tween 80 improved the activity by 63 and 15%, respectively. More importantly, L9 protease was found to be effective in dehairing of goatskins, cowhides and rabbit-skins without damaging the collagen fibers. These properties confirm the feasibility of L9 protease in industrial applications, especially in leather processing.
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http://dx.doi.org/10.4014/jmb.2108.08037DOI Listing
November 2021

Characterization of Structural and Physicochemical Properties of an Exopolysaccharide Produced by sp. F2 From Fermented Soya Beans.

Front Microbiol 2021 29;12:744007. Epub 2021 Oct 29.

College of Biomass Science and Engineering, Sichuan University, Chengdu, China.

The present study sought to isolate a novel exopolysaccharide (EPS-F2) from sp. F2 through ethanol precipitation, anion-exchange, and gel-filtration chromatography and characterize the physicochemical properties by spectral techniques. EPS-F2 was identified as a neutral homo-exopolysaccharide composed of only glucose with a high molecular weight of 1.108 × 10 g/mol. It contained →6)-α-D-Glc-(1→ linkage in the main chain and →3, 6)-α-D-Glc-(1→ branch chain). Moreover, EPS-F2 possessed excellent thermal stability (266.6°C), water holding capacity (882.5%), oil holding capacity (1867.76%), and emulsifying activity against various edible oils. The steady shear experiments exhibited stable pseudo plasticity under various conditions (concentrations, temperatures, and pHs). The dynamic oscillatory measurements revealed that EPS-F2 showed a liquid-like behavior at a low concentration (2.5%), while a solid-like behavior at high concentrations (3.0 and 3.5%). Overall, these results suggest that EPS-F2 could be a potential alternative source of functional additives and ingredients and be applied in food industries.
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http://dx.doi.org/10.3389/fmicb.2021.744007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8586432PMC
October 2021

Optimization of fermentation conditions for production of neutral metalloprotease by SCK6 and its application in goatskin-dehairing.

Prep Biochem Biotechnol 2021 Nov 8:1-11. Epub 2021 Nov 8.

Key Laboratory of Leather Chemistry and Engineering, Ministry of Education and College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu, China.

In this study, a high protease-producing strain was screened by spread plate method and identified by molecular biology and morphological identification. It was identified as sp. LCB14. A neutral protease gene was cloned and heterologous expressed by SCK6. Then, the recombinant protease was used to dehair the goat skins. The fermentation conditions of neutral protease production by SCK6 were optimized. The single factor experiments, Plackett-Burma experiment, and response surface method were conducted to determine fermentation medium and culture conditions. The optimized medium contained corn meal 49 g/L, soluble starch 28 g/L, soybean meal 17 g/L, corn steep liquor powder 8 g/L, yeast extract 10 g/L, NaHPO 2.3 g/L, KHPO 1.9 g/L, MgSO 0.5 g/L, MnCl 0.1 g/L and ZnSO 0.05 g/L. The optimized culture conditions were 35 °C and pH 7.0. Under the optimum conditions, the recombinant strain reached 33467.28 U/mL after 72 hr ferment. Moreover, by fed batch in 30 L fermenters, neutral protease production reached 39,440.78 U/mL and shortened fermentation time from 72 hr to 46 hr. Finally, the crude enzyme was utilized to replace sodium sulfide for dehairing of goatskins. The enzymatic dehaired pelts were white, smooth, and soft; the grain side of enzymatic dehaired pelts were clear; there was no obvious damage to the grain side of enzymatic dehaired pelts by visual observation and tactile test. Furthermore, there were no hair roots, hair follicles and other glands in enzymatic dehaired belts, and the collagen fibers of enzymatic dehaired belt were dispersed well by histological analysis.
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http://dx.doi.org/10.1080/10826068.2021.1995413DOI Listing
November 2021

First report of Fusarium avenaceum causing Leaf Spot on Angelica sinensis in China.

Plant Dis 2021 Oct 13. Epub 2021 Oct 13.

Lanzhou Jiaotong University, 88 West Road, Anning District, lanzhou, China, 730070;

Angelica sinensis (Oliv) Diels (Umbelliferae) is a popular Chinese herb that is mainly distributed in Gansu Province, China, accounting for more than 90% of the national output and sales. A survey for diseases of A. sinensis in Gansu Province in August 2019 found foliar disease with an incidence of 60 to100%, and severities ranging from 5 to 15%. The disease mainly occurred in late July and August. The initial symptoms included many light brown, small lesions, round or irregular in shape, which gradually increased in size. White mycelia was visible in the lesions. Severely affected leaves became chlorotic, withered and died. In the Angelica planting area in Weiyuan County (33°26'N, 104°02'E) diseased leaves from 20 plants were collected by the five-point sampling method (Zheng et al. 2018), and small samples (4 × 4 mm2) wee cut from the border between diseased and healthy tissue, successively sterilized with 75% ethanol for 30 sec, washed three times with sterilized water and dried on sterilized filter paper, and placed on potato dextrose agar plates. After 5 days at 25°C, five morphologically similar colonies were obtained. Colonies were somewhat round with pink overall and formed abundant fluffy white mycelium in the center. Conidia were solitary, macrospores slender, straight to slightly falcate with 2 to 6 septa, and ranged from 20.0 to 77.6 µm × 2.5 to 3.6 µm (n=50). The microspores were elliptical and ranged from 3.0 to 8.0 µm × 2.5 to 3.0 µm (n=5). The strong pink pigment was observed on the reverse side of the PDA culture. The morphological characteristics were consistent with the description of Fusarium avenaceum (Parikh et al. 2018; Jahedi et al. 2019). To further identify the strains, the internal transcribed spacer (ITS), β-tubulin, translation elongation factor 1α (EF1-α), and RNA polymerase second largest subunit (RPB2) gene regions were amplified with ITS1/ITS4, Bt2a/Bt2b, EF1/EF2, and 5f2/7cr (Glass and Donaldson 1995; O'Donnell et al. 2010; White et al. 1990), respectively. The sequences of the five strains were identical, and that of representative strain K0721 were deposited in GenBank (ITS, MZ389899; TUB2, MZ398139; EF1-α, MZ388462; RPB2, MZ394004). BLAST analysis revealed that the ITS, β-tubulin, EF1-α, and RPB2 sequences were 100% (563/563), 100% (423/423), 99% (643/649), and 99% (930/935) homology, with those of F. avenaceum (KP295511.1, KY475586.1, KU999088.1, and MH582082.1), respectively. A multigene phylogenetic tree was inferred by Maximum likelihood phylogenetic analyses based on the combined data set with ITS, EF1-α and RPB2. The strain K0721 was clustered with F. avenaceum. Pathogenicity tests were performed on five 1-month-old healthy plants in plastic pots (20 cm. diam.) with sterilized soil. Each was sprayed with 50 μl of a conidial suspension (1×104 conidia/mL), and 5 healthy plants were sprayed with sterile water as controls. Small lesions were observed after 5 days at 25℃ in a greenhouse. Symptoms were similar to those observed under field conditions. Control plants remained symptomless. Six isolates were reisolated from infected leaves and all confirmed to be F. avenaceum based on morphological observations and molecular identification. To our knowledge, only Septoria anthrisci has been previously reported as a pathogen of A. sinensis leaf spot (Wang et al. 2018), and this is the first report of F. avenaceum causing this disease. This discovery needs to be considered in developing and implementing disease management programs in A. sinensis production.
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http://dx.doi.org/10.1094/PDIS-08-21-1753-PDNDOI Listing
October 2021

First Report of Onion ( L.) Bulb Rot Caused by Pantoea agglomerans in China.

Plant Dis 2021 Sep 15. Epub 2021 Sep 15.

Lanzhou Jiaotong University, 88 West Road, Anning District, lanzhou, China, 730070;

Onion (Allium cepa L.) is one of the most cultivated vegetables throughout the world. With an average annual production quantity of 18 million kg in recent 21 years, China is the world's biggest onion producer (Hanci F., 2018). Among them, onion is mainly cultivated in the provinces of Gansu, Shandong, Yunnan, Jiangsu, Zhejiang and Henan. A survey in Gansu province in last several years showed that the incidence of onion bulb rot was 30%-80%. In April 2020, bulbs displayed water-soaked, and then rot symptoms observed during storage in Lanzhou City, Gansu Province, China. The initial symptoms of bulb rot disease were yellowish brown, and produced an abundant exudate in the inner bulb scales when cut. Gradually, symptomatic bulbs became soft, watery and decayed. In severe infections, the onions showed total rot of the bulb. Therefore, we sampled some diseased onions and isolated pathogenic bacteria from the junction of lesion along with healthy parts on Luria-Bertani (LB) medium. Three representative single colonies were obtained on LB medium, and the culture characteristics were raised elevation, mucoid texture, round, and smooth with entire margin, the brown at the beginning and turned yellow later, and scanning electron microscopy (SEM) observations showed that these isolates were short rod-shaped (Fig. 1A). The physiological and biochemical determination revealed that the isolates were positive for yellow pigment, v-p test, growth at 37 ℃, nitrate reduced, catalase, glucose, sucrose, D (-)-salicin, starch hydrolysis, motility, pellicle. On the contrary, they were negative for indole production, methyl red, lactose, gelatin liquefaction, glycerol, gram staining (Gavini et al., 1989; Nabrdalik et al., 2018). Based on these morphological, physiological and biochemical characteristics, three isolates were initially identified as Pantoea agglomerans (Guo et al., 2020). A representative isolate L1 was selected to extract DNA, and the conserved sequences of the pathogen gene were sequenced according to 23S ribosomal RNA (23S rRNA), DNA gyrase subunit B (gyrB), elongation factor G (fusA) (She et al., 2021) housekeeping gene. The sequence alignment of the 23S rRNA gene (P. agglomerans, MZ314289, 930bp) showed that the homology between the strain L1 and P. agglomerans (CP016889) with similarity of 99.54%, and based on the sequence alignment of gyrB (P. agglomerans, MZ337547, 1189bp) and fusA (P. agglomerans, MZ350961, 1037bp) genes, the similarity with P. agglomerans (FJ617386 and MG845872) was 100%. A phylogenetic analysis based on the 23S, gyrB, fusA housekeeping gene sequences was performed by using the neighbor-joining methods in MEGA 7.0 under the p-distance (Kumar et al, 2016), which included P. agglomerans strains AR1a, TH81, L15, ASB05, P. eucalypti strain LMG 24197, P. dispersa strains BJQ0007 and DSM 32899, P. ananatis strains LMG 20103 and AJ13355, P. vagans strains C9-1, LMG24199 and PV989. The phylogenetic distribution generated five primary phylogroups, and strain L1 formed a clade with the other four P. agglomerans strains (Fig. 2). Thus, the strain L1 was identified as P. agglomerans. To satisfy Koch's postulates, ten onions were divided into two groups, five in each group, and needle punctured wound on the surface of each onion. In the experimental group, 400 μL bacterial suspensions were injected with sterile syringe, and the other five onions were injected with the same amount of sterile distilled water as the negative conrol. Inoculated onions were incubated in the greenhouse incubator (28 ℃, humidity > 80%). After 4 days of incubation, all onions inoculated with strain L1 appeared water-soaked, rot symptoms, and no symptoms were observed in the negative control (Fig. 1B). Subsequently, pathogens were re-isolated from inoculated bulbs and identified as P. agglomerans according to molecular identification described above. To the best of our knowledge, this is the first report that the bulb rot disease of stored onion caused by P. agglomerans in China.
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http://dx.doi.org/10.1094/PDIS-07-21-1393-PDNDOI Listing
September 2021

Mechanism of Cr(VI) reduction by Lysinibacillus sp. HST-98, a newly isolated Cr (VI)-reducing strain.

Environ Sci Pollut Res Int 2021 Jul 30. Epub 2021 Jul 30.

College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China.

Facing the increasingly severe Cr(VI) pollution, bioreduction has proved to be an eco-friendly remediation method. An isolated strain identified as Lysinibacillus can relatively reduce Cr(VI) well. Even if the concentration of Cr(VI) increased to 250mg/L, the strain HST-98 could also grow and remove Cr(VI) well. After optimization of reaction conditions, the optimal pH, temperature, and electron donor are 8~9, 36°C, and sodium lactate, respectively. Coexisting metal ions such as Cu, Co, and Mn are beneficial to reduce Cr(VI), while Zn, Ni, and Cd are just the opposite. What is more, the mechanism of the reduction by the strain HST-98 is chiefly mediated by intracellular enzymes. After gene sequence homology blast and analysis, the genes and enzymes related to chromium metabolism in strain HST-98 have been annotated, which helps us to further understand the reduction mechanism of the strain HST-98. In general, Lysinibacillus sp. HST-98 is a potential candidate to repair the Cr(VI)-contaminated sites.
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http://dx.doi.org/10.1007/s11356-021-15424-xDOI Listing
July 2021

sp. nov., isolated from chromium-containing chemical plant soil.

Int J Syst Evol Microbiol 2021 Jul;71(7)

College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China.

A Gram-stain-positive, rod-shaped, aerobic, non-motile, non-sporulating bacterial strain, designated CSA1, was isolated from chromium-containing soil sampled at a chemical plant. Growth of strain CSA1 occurred at pH 6-10 (optimum, pH 7), 15-45 °C (optimum, 30 °C) and in the presence of 0.5-6.5 % (w/v) NaCl (optimum, 2 %). The 16S rRNA gene sequence of strain CSA1 revealed the highest similarity to A2 (97.5 %), K 70/01 (97.3 %), Re6 (96.6 %), F3-P9 (96.2 %), CC-MF41 (96.1 %) and S27 (96.0 %). The draft genome of CSA1 was approximately 3 350 931 bp in size with a G+C content of 70.6 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values among strain CSA1 and the selected species were 74.0-79.2 % (ANIb), 84.3-87.1 % (ANIm) and 21.5-25.4 % (dDDH), which are below the recommended cutoff values for species delineation. The major fatty acids were anteiso-C, iso-C and anteiso-C. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unknown glycolipid. The predominant menaquinones were MK-11, MK-8 and MK-6. The cell-wall amino acids were 2,4-diaminobutyric acid, alanine, glycine, glutamic acid and threonine. From the phenotypic, chemotaxonomic and molecular features, strain CSA1 was considered to represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is CSA1 (=JCM 34359=CGMCC 1.18746).
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http://dx.doi.org/10.1099/ijsem.0.004923DOI Listing
July 2021

Structural elucidation and physicochemical characteristics of a novel high-molecular-weight fructan from halotolerant Bacillus sp. SCU-E108.

Food Chem 2021 Dec 30;365:130496. Epub 2021 Jun 30.

College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China; Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China. Electronic address:

An exopolysaccharide, EPS-B108, was isolated from the fermented broth (with a yield of 11.3 g/L) of halotolerant Bacillus sp. SCU-E108 by ethanol precipitation, anion-exchange and gel-filtration chromatography, and well characterized by means of physical, chemical and spectral techniques. Data indicated that EPS-B108 was composed solely of fructose with a high molecular weight of 3.578 × 10 g/mol, and contained a β-(2 → 6)-linked d-Fruf backbone with a single β-d-Fruf at C-1 position. An irregular saccular- or cake-like shape was observed under the enlarged view. It showed no acute oral toxicity in mice, and had good thermal stability (242 °C), solubility in water (91.3%) and oil-holding capacity (1717.0%). Steady-shear flow and dynamical viscoelasticity of aqueous EPS-B108 solutions varied with the polymer concentration, shear rate and temperature, and were described by the Power-law model. Together, these findings support the further application of EPS-B108 as an alternative source of functional food additives and ingredients.
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http://dx.doi.org/10.1016/j.foodchem.2021.130496DOI Listing
December 2021

Optimization of fermentation conditions, purification and rheological properties of poly (γ-glutamic acid) produced by 1006-3.

Prep Biochem Biotechnol 2021 Jul 8:1-9. Epub 2021 Jul 8.

College of Biomass Science and Engineering, Sichuan University, Chengdu, P. R. China.

This study aimed to investigate the optimal fermentation condition, purification and rheological properties of extracellular polymers produced by 1006-3. An optimum temperature of 30.2 °C, inoculation amount of 6.1%, and pH of 8.2 were determined via Response Surface Methodology. The result of amino acid analysis and gel electrophoresis indicated that the obtained polymer contained only glutamic acid, with a wide molecular weight range. This polymer was finally determined as γ-PGA by infrared spectroscopy. The γ-PGA solution displayed a behavior of pseudoplastic non-Newtonian fluid with shear thinning properties, which can be described by the Ostward-de Waele power law model. The apparent viscosity of γ-PGA solution increased with the increase in its concentration from 1% to 10%. The deviation in pH from neutral value, and the addition of NaCl or MgCl can reduce the apparent viscosity of γ-PGA solution, and it was more sensitive to Mg than to Na addition. At the concentration of 4, 6, and 8%, γ-PGA solution showed predominantly viscous response in the range of 0.1-100 rad/s angular frequency (″>). These results indicated the potential application of the γ-PGA as a thickening agent.
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http://dx.doi.org/10.1080/10826068.2021.1941103DOI Listing
July 2021

Melt-processed poly (vinyl alcohol)/corn starch/nanocellulose composites with improved mechanical properties.

Int J Biol Macromol 2021 Jul 6;183:1903-1910. Epub 2021 Jun 6.

State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China. Electronic address:

Corn starch (CS) and cellulose nanofibrils (CNFs) were incorporated into biodegradable poly (vinyl alcohol) (PVA) to prepare mechanically robust and sustainable composites through melt-processing. Based on the regulation and control of hydrogen bonding network, CS and CNFs can extend the processing window and improve the thermoplasticity of PVA composites. Fourier transform infrared spectroscopy and Raman spectra analysis indicate that the intra- and inter-molecular hydrogen bonds of PVA are broken, accompanied by the formation of new hydrogen bonds among PVA, CS and CNFs during the melt-processing treatment. Thermal analysis shows that the processing window of PVA composite is significantly broadened to 131.46 °C. The tensile strength, modulus and elongation at break of the composites reach to 28.19 MPa, 1572.54 MPa and 10.72% by the incorporation of 10 wt% CS and 10 wt% CNFs. This strategy is not only expected to provide a direction for preparing complex three-dimensional products of PVA by melt-processing, but also provide a method to enhance the mechanical properties of other biodegradable plastics.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.06.011DOI Listing
July 2021

Salt-induced recruitment of specific root-associated bacterial consortium capable of enhancing plant adaptability to salt stress.

ISME J 2021 10 19;15(10):2865-2882. Epub 2021 Apr 19.

Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing, P. R. China.

Salinity is a major abiotic stress threatening crop production. Root-derived bacteria (RDB) are hypothesized to play a role in enhancing plant adaptability to various stresses. However, it is still unclear whether and how plants build up specific RDB when challenged by salinity. In this study, we measured the composition and variation in the rhizosphere and endophyte bacteria of salt-sensitive (SSs) and salt-resistant (SRs) plants under soil conditions with/without salinity. The salt-induced RDB (both rhizobiomes and endophytes) were isolated to examine their effects on the physiological responses of SSs and SRs to salinity challenge. Moreover, we examined whether functional redundancy exists among salt-induced RDB in enhancing plant adaptability to salt stress. We observed that although SSs and SRs recruited distinct RDB and relevant functions when challenged by salinity, salt-induced recruitment of specific RDB led to a consistent growth promotion in plants regardless of their salinity tolerance capacities. Plants employed a species-specific strategy to recruit beneficial soil bacteria in the rhizosphere rather than in the endosphere. Furthermore, we demonstrated that the consortium, but not individual members of the salt-induced RDB, provided enduring resistance against salt stress. This study confirms the critical role of salt-induced RDB in enhancing plant adaptability to salt stress.
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http://dx.doi.org/10.1038/s41396-021-00974-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8443564PMC
October 2021

Hexavalent chromium reducing bacteria: mechanism of reduction and characteristics.

Environ Sci Pollut Res Int 2021 May 10;28(17):20981-20997. Epub 2021 Mar 10.

College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.

As a common heavy metal, chromium and its compounds are widely used in industrial applications, e.g., leather tanning, electroplating, and in stainless steel, paints and fertilizers. Due to the strong toxicity of Cr(VI), chromium is regarded as a major source of pollution with a serious impact on the environment and biological systems. The disposal of Cr(VI) by biological treatment methods is more favorable than traditional treatment methods because the biological processes are environmentally friendly and cost-efficient. This review describes how bacteria tolerate and reduce Cr(VI) and the effects of some physical and chemical factors on the reduction of Cr(IV). The practical applications for Cr(VI) reduction of bacterial cells are also included in this review.
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http://dx.doi.org/10.1007/s11356-021-13325-7DOI Listing
May 2021

Label-free proteomic dissection on dptP-deletion mutant uncovers dptP involvement in strain growth and daptomycin tolerance of Streptomyces roseosporus.

Microb Biotechnol 2021 03 24;14(2):708-725. Epub 2020 Dec 24.

State Key Laboratory of Biotherapy and Cancer Center, Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.

Daptomycin (DAP) is a novel microbial lipopeptide antibiotic synthesized by the DAP biosynthetic gene cluster dpt of Streptomyces roseosporus (S. roseosporus). DptP gene locates upstream of dpt and confers DAP resistance to Streptomyces ambofaciens (S. ambofaciens). So far, the biological functions of dptP gene for S. roseosporus growth are still completely uncovered. We performed label-free quantification proteomic dissections with loss- and gain-of-function experiments to decipher dptP-involved functions. Deletion of dptP gene activated energy metabolism and metabolism of secondary metabolites pathways and enhanced the transcription levels and protein abundance of key members of the dpt cluster. Whereas dptP deletion inhibited transport/signal transduction and drug resistance pathways and protein abundance of cell division-relative proteins, subsequently decreased mycelia cell growth rate. S. roseosporus strain with dptP deletion was more sensitive to DAP treatment compared to the wild type. In contrast, overexpression of dptP gene decreased transcription levels of DAP biosynthetic genes and enhanced growth rate of Streptomcyes strain upon elevated culture temperature and DAP supplementation. Taken together, dptP gene contributes to Streptomcyes primary growth under elevated temperature and DAP treatment, whereas it plays negative roles on metabolism of secondary metabolites and transcription of DAP biosynthetic genes.
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http://dx.doi.org/10.1111/1751-7915.13736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7936300PMC
March 2021

First Report of Alternaria tenuissimain Causing Leaf Spot of Celery (Apium graveolens) in China.

Plant Dis 2020 Nov 24. Epub 2020 Nov 24.

Lanzhou Jiaotong University, 88 West Road, Anning District, lanzhou, China, 730070;

Celery (Apium graveolens) is one of the most widely grown vegetables in the world. A survey in Anding District of Gansu Province in 2019 showed that the incidence of celery leaf spot was 25%-45%. The disease mainly occurs in late June and July. The leaf spot is conducive to the onset at high temperature and humidity environment. The initial symptoms were many small light brown, irregular-shaped on the leaves. The lesions gradually enlarged in the later stage of the disease, and multiple lesions coalesced to form large irregular brown spots, eventually the whole leaves died. A 3~4mm leaf tissue was cut from the junction of the diseased leaf and the healthy area, the leaf tisse was surface-sterilized in 1.5% NaClO for 1 min and washed with sterile water. Then, it was incubated on potato dextrose agar (PDA) and obtained the pure culture (Q1). After 5 days of cultivation at 25°C, the fungal colonies were olivaceous to dark olive with white margins and abundant aerial mycelia. The conidia were obclavate or ellipsoid, pale brown, with 3~4 longitudinal septa and 2~7 transverse septa, and measured 20.0 to 50.0 × 3.5 to 14.0μm (n=50). Conidiophores were septate, arising singly, and measured 3.5 to 40.0 × 2.5 to 4.5 μm (n=50). Based on morphological characteristics, the fungus was preliminarily identified as A.tenuissima (Simmons 2007). To further confirm the identification, the internal transcribed spacer region (ITS), translation elongation factor 1-α gene (TEF), RNA polymerase II second largest subunit (RPB2), major allergen Alt a 1 gene (Alt a 1), endopolygalacturonase gene (endoPG), anonymous gene region (OPA10-2) and glyceraldehyde 3-phos-phatedehydrogenase (GAPDH) were amplified and sequenced using primers ITS1/ITS4 (Peever et al. 2004), EF1-728F/EF1-986R (Carbone et al. 1999), RPB2-5F2/RPB2-5R (Sung et al. 2007), Alt-for/Alt-rev (Hong et al. 2005), EPG-specific/EPG-3b (Peever et al. 2004), OPA10-2R/OPA10-2L (Peever et al. 2004) and Gpd1/Gpd2 (Berbee et al. 1999) (GenBank accession no.MN046364, MW016001, MW016002, MW016003, MW016004, MW016005, MW016006). DNA sequences of TEF, RPB2, endoPG, OPA10-2 and GAPDH were 100% identical to those of A. tenuissima (MN256108, MK605866, KP789503, JQ859829 and MK683802), but ITS and Alt a 1 were 100% similarity with A. tenuissima (MN615420, JQ282277) and A. alternate (MT626589, KP123847). The ITS and Alt a 1 sequence did not distinguish A. tenuissima from the A. alternate complex. Maximum likelihood phylogenetic analyses were performed for the combined data set with TEF, RPB2, and endoPG using MEGA6 under the Tamura-Nei model (Kumar et al. 2016). The isolate Q1 clustered with type strain A. tenuissima CBS 918.96. The 20 celery plants of 4-7 leaf age were used test the pathogenicity of Q1, the ten plants were sprayed with 20ml of spore suspension (1×105 spores/ml), the control was sprayed with 20mL sterile water, which were placed in a growth chamber (25℃, a 14h light and 10h dark period, RH > 80%). Eight days after inoculation, 40% of the leaves formed lesions, which were consistent with the field observation,the control group was asymptomatic. The pathogen was reisolated from infected leaves to fulfill Koch's postulates. To our knowledge, this is the first report of A. tenuissima causing leaf spot on celery in China.
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http://dx.doi.org/10.1094/PDIS-09-20-2083-PDNDOI Listing
November 2020

Vermicomposting of livestock manure as affected by carbon-rich additives (straw, biochar and nanocarbon): A comprehensive evaluation of earthworm performance, microbial activities, metabolic functions and vermicompost quality.

Bioresour Technol 2021 Jan 12;320(Pt B):124404. Epub 2020 Nov 12.

College of Agriculture, Ningxia University, Helanshan Xilu No. 489, Yinchuan 750021, China.

Vermicomposting is an eco-friendly method for treating organic wastes. This study investigated the effects of the addition of straw (S), biochar (B), nanocarbon (N), S + B and S + N to cow dung (CD) on earthworm (Eisenia fetida) performance, microbial properties and vermicompost quality. In general, the earthworm growth rate and cocoon production were enhanced by straw addition, but were inhibited by biochar or nanocarbon addition. However, biochar and nanocarbon increased microbial communities associated with organic matter decomposition, and improved metabolic functions, enzyme activities and vermicompost properties. Moreover, addition of straw in combination with nanocarbon resulted in the highest vermicompost quality index (VQI), and significantly increased the biomass of three different test crops (radish, lettuce and pakchoi). These results indicated that biochar and nanocarbon mainly improved microbial activities, while straw primarily enhanced earthworm performance during vermicomposting. In addition, straw combined with nanocarbon can be used to enhance the agronomic performance of vermicompost.
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http://dx.doi.org/10.1016/j.biortech.2020.124404DOI Listing
January 2021

Genome-Wide Identification, Structural, and Gene Expression Analysis of BRI1-EMS-Suppressor 1 Transcription Factor Family in .

Front Genet 2020 6;11:583996. Epub 2020 Oct 6.

Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing, China.

BRASSINOSTEROID INSENSITIVE1-EMS-suppressor 1 (BES1) is an essential regulator downstream of brassinosteroid signaling and plays important roles in plant stress response, growth, and development. To date, the regulation mechanisms of BES1 transcription factors have been identified and elucidated in model plants Arabidopsis and rice. However, little information is available regarding the BES1 family in . Therefore, this study conducted a genome-wide analysis of BES1 genes in cucumber. In cucumber, a total of six CsBES1 genes were identified, and their phylogenetic relationships, gene structures, and -elements in promoters were studied. genes were distributed on four of seven chromosomes. Gene structure analysis showed that the intron-exon model of genes was conserved and the CsBES1 protein contained a DUF822-conserved motif. Promoter -element prediction showed that plenty of developmental and stress- and hormone-related elements have been found in promoter regions of genes. Meanwhile, BES1 was divided into three groups (I, II, and III) on the basis of phylogenetic relationship analysis in six plant species. In addition, gene expression patterns were confirmed by transcription database and qRT-PCR analysis; the results showed that the expression of genes had not only tissue-specific expression but also different types of isoform which might respond to specific plant stresses. In summary, genome-wide identification, phylogeny, gene structure, and expression profile analysis of genes in cucumber provided a referable theoretical information for further functional study of genes and further facilitated the molecular breeding of cucumber.
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http://dx.doi.org/10.3389/fgene.2020.583996DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7573293PMC
October 2020

Biosorption of Congo Red from Aqueous Solutions Based on Self-Immobilized Mycelial Pellets: Kinetics, Isotherms, and Thermodynamic Studies.

ACS Omega 2020 Sep 17;5(38):24601-24612. Epub 2020 Sep 17.

Research Institute, Lanzhou Jiaotong University, Lanzhou 730070, China.

In the current study, and were co-cultured to obtain self-immobilized mycelial pellets to evaluate the decolorization efficiency of Congo red (CR). The obtained co-culture exhibited the highest decolorization efficiency of 99.22% compared to monoculture of (89.20%) and (55.04%). The morphology and surface properties of the mycelial pellets were characterized by SEM, FTIR, BET, and XPS. The adsorption kinetics and isotherms were well described by pseudo-second-order and Langmuir models. The findings revealed that the removal efficiency of the mycelial pellet for CR was significantly influenced by physicochemical parameters. Thermodynamic result showed that the biosorption process was endothermic. The maximum adsorption capacity can be obtained from the Langmuir model, which is 316.46 mg/g, it suggests that mycelial pellet was an efficient biosorbent to remove CR from aqueous solution. This study indicates that the mycelial pellet can develop a sustainable approach to eliminate CR from the wastewater.
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http://dx.doi.org/10.1021/acsomega.0c03114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528287PMC
September 2020

sp. nov., a moderately halophilic bacterium isolated from wetsalted hides.

Int J Syst Evol Microbiol 2020 Oct 4;70(10):5417-5424. Epub 2020 Sep 4.

Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China.

A Gram-stain-negative, moderately halophilic strain, designated strain L5, was isolated from wetsalted hides collected from Chengdu, south-west PR China. The cells were motile, facultative aerobic, short rod-shaped and non-endospore-forming. Growth of strain L5 occurred at pH 6-10 (optimum, pH 8), 10-45 °C (optimum, 30 °C) and in the presence of 1-17 % (w/v) NaCl (optimum, 10 %). Results of phylogenetic analyses based on 16S rRNA, and gene sequences and its genome revealed that strain L5 belonged to the genus . Strain L5 was found to be most closely related to the type strains of , , , and (98.8, 98.6, 98.3, 97.9 and 97.4 % 16S rRNA gene sequence similarity, respectively). The draft genome was approximately 4.2 Mb in size with a G+C content of 63.5 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization values among strain L5 and the selected species were 83.3-88.9 % (ANIm), 71.1-87.3 % (ANIb) and 20.2-34.6 %, which are below the recommended cutoff values. Major fatty acids were C, C 7, C 7 and C cyclo 8 and the predominant ubiquinone was Q-9, with minor ubiquinone Q-8 also present. The phospholipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four unidentified aminophospholipids and three unidentified phospholipids. Based on the mentioned polyphasic taxonomic evidence, strain L5 represents a novel species within the genus , for which sp. nov. is proposed. The type strain is L5 (=CGMCC 1.17335=KCTC 72573).
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http://dx.doi.org/10.1099/ijsem.0.004426DOI Listing
October 2020

Genomic insights into the salt tolerance and cold adaptation of Planococcus halotolerans SCU63.

Arch Microbiol 2020 Dec 17;202(10):2841-2847. Epub 2020 Jul 17.

College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.

Planococcus halotolerans, recently described as a novel species with SCU63 as the type strain, is capable of thriving in up to 15% NaCl and temperatures as low as 0 °C. To better understand its adaptation strategies at the genomic level, strain SCU63 was subjected to whole-genome sequencing and data mining. The high-quality assembly yielded 17 scaffolds with a genome size of 3,622,698 bp. Its genome harbors 3683 protein-coding sequences and 127 RNA genes, as well as three biosynthetic gene clusters and 25 genomic islands. The phylogenomic tree provided compelling insights into the evolutionary relationships of Planococcus. Comparative genomic analysis revealed key similarities and differences in the functional gene categories among Planococcus species. Strain SCU63 was shown to have diverse stress response systems for high salt and cold habitats. Further comparison with three related species showed the presence of numerous unique gene clusters in the SCU63 genome. The strain might serve as a good model for using extremozymes in various biotechnological processes.
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http://dx.doi.org/10.1007/s00203-020-01979-9DOI Listing
December 2020

Biochar combined with gypsum reduces both nitrogen and carbon losses during agricultural waste composting and enhances overall compost quality by regulating microbial activities and functions.

Bioresour Technol 2020 Oct 5;314:123781. Epub 2020 Jul 5.

Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, China. Electronic address:

Composting is an efficient method for treating agricultural wastes. This study investigated the effects of the addition of biochar (B) and gypsum (G) to straw mixed with chicken manure (SC) (i.e. SC, SC + B, SC + G and SC + B + G) on composting performance at different initial C/N ratios (20, 25 and 30). In general, biochar combined with gypsum (BCG) efficiently shortened composting time and reduced N loss, C loss and potential ecological risk. It also enhanced lignocellulose decomposition, nutrient retention and the overall compost quality expressed by a compost quality index (CQI), and increased the biomass of four different test crops. The BCG-induced increase in CQI was closely associated with microbial enzyme activities and C catabolic profiles. These results indicated that the combination of biochar and gypsum is more effective than each single additive during composting, and emphasized that microbial activities and functions play pivotal roles in determining compost quality and thereby agronomic performance.
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http://dx.doi.org/10.1016/j.biortech.2020.123781DOI Listing
October 2020

sp. nov., a moderate halophile isolated from saline soil in Northwest China.

Int J Syst Evol Microbiol 2020 Jun 15;70(6):3701-3710. Epub 2020 May 15.

Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China.

A moderately halophilic strain, designated SCU50, was recovered from a saline soil sample and characterized by a polyphasic approach. The 16S rRNA gene sequence analysis showed that strain SCU50 belonged to the genus and was most closely related to TP2-8 (98.1 % similarity) and XH-63 (97.7 %). Genomic average nucleotide identity and digital DNA-DNA hybridization analyses confirmed the separate species status of the new isolate relative to other recognized species. The genome size was about 5.09 Mbp and the DNA G+C content was 36.7 mol%. The strain grew optimally at 10-15 % (w/v) NaCl, pH 6.5-7.5 and 25-30 °C. It contained anteiso-C, iso-C and anteiso-C as the dominant fatty acids and menaquinone-7 as the major respiratory quinone. The polar lipid profile was examined and found to comprise diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and one unidentified lipid. The cell-wall peptidoglycan type was A1γ based on -diaminopimelic acid. Combining the data from phenotypic, chemotaxonomic, genomic and phylogenetic characterization, it was concluded that strain SCU50 should be assigned as representing a novel species within the genus . Thus, a novel taxon named sp. nov. was first established, with SCU50 (=CGMCC 1.17336=KCTC 43107) as the type strain.
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http://dx.doi.org/10.1099/ijsem.0.004224DOI Listing
June 2020

Heterologous Expression of Recombinant Transglutaminase in SCK6 with Optimized Signal Peptide and Codon, and Its Impact on Gelatin Properties.

J Microbiol Biotechnol 2020 Jul;30(7):1082-1091

Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, P.R. China.

Microbial transglutaminases (MTGs) are widely used in the food industry. In this study, the MTG gene of sp. TYQ1024 was cloned and expressed in a food-grade bacterial strain, SCK6. Extracellular activity of the MTG after codon and signal peptide (SP Ync M) optimization was 20 times that of the pre-optimized enzyme. After purification, the molecular weight of the MTG was 38 kDa and the specific activity was 63.75 U/mg. The optimal temperature and pH for the recombinant MTG activity were 50°C and 8.0, respectively. MTG activity increased 1.42- fold in the presence of β-ME and 1.6-fold in the presence of DTT. Moreover, 18% sodium chloride still resulted in 83% enzyme activity, which showed good salt tolerance. Cross-linking gelatin with the MTG increased the strength of gelatin 1.67 times and increased the thermal denaturation temperature from 61.8 to 75.8°C. The MTG also significantly increased the strength and thermal stability of gelatin. These characteristics demonstrated the huge commercial potential of MTG, such as for applications in salted protein foods.
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http://dx.doi.org/10.4014/jmb.2002.02049DOI Listing
July 2020

Description of Salinicola corii sp. nov., a Halotolerant Bacterium Isolated from Wetsalted Hides.

Curr Microbiol 2020 Aug 20;77(8):1932-1938. Epub 2020 Apr 20.

Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.

A novel Gram-stain-negative, moderately halotolerant, rod-shaped bacterium, designated strain L3, was isolated from a wetsalted hide in Chengdu, China. The organism grew optimally at 30 °C, at pH 8 and with 5-10% (w/v) NaCl. The major cellular fatty acids were C, Cω7c, Cω7c and C cyclo ω8c; the predominant respiratory quinone was Q-9; the phospholipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and three unidentified phospholipids. Phylogenetic trees based on the 16S rRNA, gyrB and rpoD genes' sequences, obtained using three different algorithms, clearly revealed the isolate belonged to the genus Salinicola, and was found to be closely related to Salinicola acroporae JCM 30412, Salinicola socius CGMCC 1.12383 and Salinicola lusitanus CR50. The draft genome was approximately 4.5 Mb in size with 4486 predicted coding sequences, and the G+C content was 62.6 mol%. The maximum values of ANI and dDDH between strain L3 and the three above-mentioned type species were 89.2% and 63.8%, respectively. Differential phenotypic properties, together with the genome analysis, support the view that strain L3 represents a novel species, Salinicola corii sp. nov., with the type strain L3 (=CGMCC 1.17272=KCTC 72572).
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http://dx.doi.org/10.1007/s00284-020-01989-2DOI Listing
August 2020

Preparation, characterization and functional properties of a novel exopolysaccharide produced by the halophilic strain Halomonas saliphila LCB169.

Int J Biol Macromol 2020 Aug 11;156:372-380. Epub 2020 Apr 11.

College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China; Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China. Electronic address:

A novel exopolysaccharide, designated hsEPS, was successfully prepared from the high-salt-fermented broth of a novel species Halomonas saliphila LCB169 by ethanol precipitation, anion-exchange and gel-filtration chromatography, and its structure was well-characterized by means of chemical and spectral analyses. Results showed that hsEPS was primarily composed of mannose and glucose with a relative weight-average molecular weight of 5.133 × 10 g/mol. It was deduced that the major backbone contained (1→2)-linked α-D-Manp and (1→6)-linked α-D-Manp with branches substituted at C-2 by T-α-D-Manp and at C-6 by the fragment of T-α-D-Manp-(1→2)-α-D-Manp-(1→. A sheet-like structure was observed under high magnification. The water solubility index, water holding capacity, oil holding capacity and foaming capacity of hsEPS were 98.0, 19.3, 1386.7 and 82.2%, respectively. It also exhibited outstanding emulsifying activity against all tested edible oils. Together, the resulted data indicated that hsEPS might serve as an active ingredient in food, cosmetics and detergents.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.04.062DOI Listing
August 2020

Ornithinibacillus caprae sp. nov., a moderate halophile isolated from the hides of a white goat.

Arch Microbiol 2020 Aug 19;202(6):1469-1476. Epub 2020 Mar 19.

College of Biomass Science and Engineering, Sichuan University, Chengdu, People's Republic of China.

A novel Gram-stain-positive, motile, moderate halophile, strain L9, was isolated from hides of white goat in China. The isolate grew optimally at 30 °C, at pH 7 and with 5-10% (w/v) NaCl. The predominant menaquinone was MK-7, and the major cellular fatty acids were identified as iso-C and anteiso-C. The peptidoglycan amino acid type was determined to be A4β, containing L-ornithine and D-aspartic as diagnostic amino acids. The phospholipids were dominated by diphosphatidylglycerol, phosphatidylglycerol, one unidentified aminophospholipid and two unidentified phospholipids. Genome sequencing resulted in a genome size of 4.0 Mbp and a DNA G + C content of 35.9 mol%. Phylogenetic trees based on the 16S rRNA gene sequences showed the isolate to be closely related to Oceanobacillus limi H9B (98.2% similarity) and Ornithinibacillus halophilus G8B (97.5% similarity). The ANI and dDDH values between strain L9 and the closely related species were 69.8-76.1% and 13.0-20.5%, respectively. On the basis of the data presented, strain L9 represents a novel species of the genus Ornithinibacillus, for which the name Ornithinibacillus caprae sp. nov. is proposed. The type strain is L9 (= KCTC 43176 = CGMCC 1.17659).
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http://dx.doi.org/10.1007/s00203-020-01855-6DOI Listing
August 2020

sp. nov., a pesticide-degrading bacterium isolated from the insect living in deserted cropland.

Int J Syst Evol Microbiol 2020 Apr 24;70(4):2217-2225. Epub 2020 Feb 24.

Key laboratory of Leather Chemistry and Engineering, Ministry of Education and College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China.

A Gram-stain-negative, non-spore-forming, motile, aerobic, rod-shaped bacteria strain, designated LCB8, was isolated from the insect captured from a deserted cropland in Shuangliu district, Chengdu, PR China. Phylogenetic analysis on the basis of 16S rRNA gene sequence indicated that the strain represented a member of the genus , family , class CCUG 60088 (97.9 %) and CCUG 38531 (98.8 %) were identified as the most closely related phylogenetic neighbours of strain LCB8. The novel strain was able to grow at salt concentrations of 0-4.5 % (w/v), pH 5-9 and temperatures of 20-42 °C. The major quinone system was ubiquinone Q-10, the major fatty acids were Cω7, C and C. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol and four undefined aminolipids. The major polyamines were putrescine and spermidine. Genome sequencing revealed a genome size of 4.76 Mbp and a DNA G+C content of 57.1 mol%. These phenotypic, genotypic and chemotaxonomic traits excellently supported the affiliation of LCB8 to the genus . Pairwise determined whole-genome average nucleotide identity (ANI) values indicated that strain LCB8 represents a novel species, for which we propose the name sp. nov. with the type strain LCB8 (=KCTC 72031=CGMCC 1.13984).
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http://dx.doi.org/10.1099/ijsem.0.003964DOI Listing
April 2020

Draft genome sequence of A251, an actinomycetes producing polyketides and nonribosomal polypeptides.

3 Biotech 2020 Feb 30;10(2):79. Epub 2020 Jan 30.

Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, College of Biomass Science and Engineering, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu, 610065 People's Republic of China.

In this work, we present the draft genome sequence of A251 consisting of 8,253,402 bp with a G + C content of 71.5 mol%. The genome sequence includes 3 5S rRNA genes, 54 tRNA genes, 28 snRNA genes and 19 CRISPRs in 26 contigs. Using the Rapid Annotation using Subsystem Technology, a total of 7766 coding DNA sequences, which were assigned to 436 subsystems, were found in the genome. And 6743 protein-coding sequences with designated functions were assigned to 19 categories in the Cluster of Orthologous Groups database. The genome contains 20 gene clusters responsible for the synthesis of secondary metabolites, including two type I polyketide synthase (PKS) gene clusters, two type III PKS gene clusters, three nonribosomal peptide synthetase (NRPS) gene clusters and two hybrid PKS/NRPS gene clusters. These results indicate that strain A251 has the ability to produce several nonribosomal polypeptides and diverse polyketides, which was verified by liquid chromatography-mass spectrometry analysis of the extraction from fermentation broth. In addition, lactones, indole and many unknown natural products are present in the metabolites. Bioactivity testing revealed anticancer and antidiabetic activities of the crude extract towards the cancer cell line HepG2. In summary, the genomic sequences and bioactive fermentation products demonstrate the potential of strain A251 in biotechnology.
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http://dx.doi.org/10.1007/s13205-020-2070-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992827PMC
February 2020

Structural characterization and functional evaluation of a novel exopolysaccharide from the moderate halophile Gracilibacillus sp. SCU50.

Int J Biol Macromol 2020 Jul 19;154:1140-1148. Epub 2019 Nov 19.

College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China; Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China. Electronic address:

A novel exopolysaccharide (named mhEPS) with a molecular weight of 5.881 × 10 g/mol was isolated from Gracilibacillus sp. SCU50's high-salt fermentation broth by ethanol precipitation, anion-exchange and gel-filtration chromatography before being structurally characterized and functionally evaluated. mhEPS consists of mannose, galactose, glucose and fucose in a molar ratio of 90.81:5.76:2.22:1.21. The backbone of mhEPS was (1→3,6)-linked α-D-mannopyranose residues, branched by single α-D-mannopyranose units attached to the main chain at C-2 position of every residue. The water solubility index, water holding capacity and oil holding capacity of mhEPS were 93.53, 14.89 and 1023.34%, respectively. mhEPS showed to possess good emulsifying activity against all tested substrates, and it could potentially increase the high-salinity tolerance of strain SCU50. The lack of toxicity of mhEPS was also preliminarily determined. Due to the functional properties of mhEPS, it is a good candidate to develop as an active ingredient in food, cosmetics and detergents.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.11.143DOI Listing
July 2020

Cloning, heterologous expression and characterization of a novel streptomyces trypsin in Bacillus subtilis SCK6.

Int J Biol Macromol 2020 Mar 15;147:890-897. Epub 2019 Nov 15.

Key Laboratory of Leather Chemistry and Engineering, Ministry of Education and College of Biomass Science & Engineering, Sichuan University, Chengdu 610065, PR China. Electronic address:

A novel streptomyces trypsin GM2938 was selected as the object of study. The active GM2938 contains 223 amino acid residues. Constructing recombinant plasmid and transforming Bacillus subtilis SCK6, the heterogenous expression of GM2938 was achieved. Through optimization of fermentation conditions, the expression level of GM2938 reached 1622.2 U/mL (esterase activity) and 33.8 U/mL (amidase activity). The recombinant trypsin was purified and measured: the specific activity of esterase was 5.6 × 10 U/mg, and the specific activity of amidase was 1.1 × 10 U/mg. Furthermore, the enzymatic properties of GM2938 were explore: the optimal reaction temperature and pH were 50 °C and 9.0, respectively; the recombinant enzyme show high stability at 25 °C and range of pH 5.0-9.0; Ca, K, Mg, EDTA, DTT, DMSO, methanol, glycerin and ethanediol could promote the esterase and amidase activities at the investigated concentrations, while Fe, SDS, tritonx-100, acetone, chloroform and n-hexane inhibited the trypsin activities. Kinetic parameters of GM2938 were calculated: the Km of BAEE was 3.15 × 10 mol·L, Vmax value was 2.87 × 10 mol·L·min; the Km of BAPAN was 2.20 × 10 mol·L, the Vmax was 2.40 × 10 mol·L·min. These properties give trypsin GM2938 a potential application prospect.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.09.248DOI Listing
March 2020
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