scholarly journals Identification and Nematicidal Characterization of Proteases Secreted by Endophytic Bacteria Bacillus cereus BCM2

2020 ◽  
Vol 110 (2) ◽  
pp. 336-344 ◽  
Author(s):  
Haijing Hu ◽  
Yang Gao ◽  
Xia Li ◽  
Shuanglin Chen ◽  
Shuzhen Yan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bacillus Cereus ◽  
Endophytic Bacteria ◽  
Endophytic Bacterium ◽  
Extracellular Proteins ◽  
Nematicidal Activity ◽  
Alkaline Serine Protease ◽  
Transmission Electron ◽  
Nematode Cuticle ◽  
Bacterium Bacillus

The endophytic bacterium Bacillus cereus BCM2 has shown great potential as a biocontrol organism against Meloidogyne incognita, which causes severe root-knot diseases in crops. In our previous study, the metabolite of BCM2 showed high nematicidal activity against the M. incognita second-stage juveniles. However, the mechanism employed by endophytic bacteria to infect and kill nematodes is still unclear. Here, we investigate both the endophytic bacterial extracellular proteins with nematicidal activity and their mechanism of killing nematodes. The first step was detecting the nematicidal activities of crude proteins. The results show that the nematode mortality rate reached 100% within 72 h, and the crude proteins damaged both the cuticle and eggshell, before finally destroying the targets. This suggests possible proteinaceous pathogeny in BCM2. Throughout the process, the fine-detail changes in the nematode cuticle and the intestinal structure were observed using scanning electron microscopy and transmission electron microscopy. These images show that BCM2 extracellular proteins did not damage the internal organization of the nematode but did severely damage its cuticle, which led to content leakage. From the crude proteins, chitosanase, alkaline serine protease, and neutral protease were purified and identified. The M. incognita–B. cereus BCM2 microenvironment simulation demonstrates that BCM2 adheres to the surface of nematodes and helps the metabolites that were produced by BCM2 to rapidly recognize and kill M. incognita. This relationship between plants, endophytic bacteria, and nematodes offers insight into the biological mechanisms that can be utilized for of nematode management.

scholarly journals Behavior and Mechanism of Cesium Biosorption from Aqueous Solution by Living Synechococcus PCC7002

2020 ◽  
Vol 8 (4) ◽  
pp. 491 ◽  
Author(s):  
Runlan Yu ◽  
Hongsheng Chai ◽  
Zhaojing Yu ◽  
Xueling Wu ◽  
Yuandong Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Extracellular Polymeric Substances ◽  
Three Dimensional ◽  
Vital Role ◽  
Extracellular Proteins ◽  
Biosorption Mechanism ◽  
Transmission Electron ◽  
Passive Adsorption ◽  
Pseudo Second Order ◽  
Cs Ions

Many efforts have focused on the adsorption of metals from contaminated water by microbes. Synechococcus PCC7002, a major marine cyanobacteria, is widely applied to remove metals from the ocean’s photic zone. However, its ability to adsorb cesium (Cs) nuclides has received little attention. In this study, the biosorption behavior of Cs(I) from ultrapure distilled water by living Synechococcus PCC7002 was investigated based on kinetic and isotherm studies, and the biosorption mechanism was characterized by Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and three-dimensional excitation emission matrix fluorescence spectroscopy. Synechococcus PCC7002 showed extremely high tolerance to Cs ions and its minimal inhibitory concentration was 8.6 g/L. Extracellular polymeric substances (EPS) in Synechococcus PCC7002 played a vital role in this tolerance. The biosorption of Cs by Synechococcus PCC7002 conformed to a Freundlich-type isotherm model and pseudo-second-order kinetics. The binding of Cs(I) was primarily attributed to the extracellular proteins in EPS, with the amino, hydroxyl, and phosphate groups on the cell walls contributing to Cs adsorption. The biosorption of Cs involved two mechanisms: Passive adsorption on the cell surface at low Cs concentrations and active intracellular adsorption at high Cs concentrations. The results demonstrate that the behavior and mechanism of Cs adsorption by Synechococcus PCC7002 differ based on the Cs ions concentration.

scholarly journals Biosynthesis of Silver Nanoparticles Using Onion Endophytic Bacterium and Its Antifungal Activity against Rice Pathogen Magnaporthe oryzae

2020 ◽  
Vol 6 (4) ◽  
pp. 294
Author(s):  
Ezzeldin Ibrahim ◽  
Jinyan Luo ◽  
Temoor Ahmed ◽  
Wenge Wu ◽  
Chenqi Yan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Magnaporthe Oryzae ◽  
Fungal Infections ◽  
Endophytic Bacterium ◽  
Energy Dispersive Spectrum ◽  
Safe Alternative ◽  
Bacterium Bacillus ◽  
Biosynthesized Agnps

Biosynthesis of silver nanoparticles (AgNPs) using endophytic bacteria is a safe alternative to the traditional chemical method. The purpose of this research is to biosynthesize AgNPs using endophytic bacterium Bacillus endophyticus strain H3 isolated from onion. The biosynthesized AgNPs with sizes from 4.17 to 26.9 nm were confirmed and characterized by various physicochemical techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in addition to an energy dispersive spectrum (EDS) profile. The biosynthesized AgNPs at a concentration of 40 μg/mL had a strong antifungal activity against rice blast pathogen Magnaporthe oryzae with an inhibition rate of 88% in mycelial diameter. Moreover, the biosynthesized AgNPs significantly inhibited spore germination and appressorium formation of M. oryzae. Additionally, microscopic observation showed that mycelia morphology was swollen and abnormal when dealing with AgNPs. Overall, the current study revealed that AgNPs could protect rice plants against fungal infections.

scholarly journals Complete Genome Sequence of the Endophytic Bacterium Bacillus cereus PgBE311, Isolated from Panax ginseng

2018 ◽  
Vol 7 (21) ◽  
Author(s):  
Chi Eun Hong ◽  
Jang Uk Kim ◽  
Jung Woo Lee ◽  
Kyong Hwan Bang ◽  
Ick-Hyun Jo
Keyword(s):  
Bacillus Cereus ◽  
Panax Ginseng ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Fungal Pathogens ◽  
Endophytic Bacterium ◽  
Content Type ◽  
Cylindrocarpon Destructans ◽  
Bacterium Bacillus

Bacillus cereus PgBE311, isolated from the root tissue of a 5-year-old Panax ginseng plant, showed activities against the fungal pathogens Cylindrocarpon destructans and Botrytis cinerea. Here, we report the genome sequence of B. cereus PgBE311.

scholarly journals Silver Nanoparticles Synthesized by Using the Endophytic Bacterium Pantoea ananatis are Promising Antimicrobial Agents against Multidrug Resistant Bacteria

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3220 ◽  
Author(s):  
Tahmina Monowar ◽  
Md. Rahman ◽  
Subhash Bhore ◽  
Gunasunderi Raju ◽  
Kathiresan Sathasivam
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Candida Albicans ◽  
Bacillus Cereus ◽  
Antimicrobial Agents ◽  
Endophytic Bacterium ◽  
Multidrug Resistant ◽  
Pantoea Ananatis

Antibiotic resistance is one of the most important global problems currently confronting the world. Different biomedical applications of silver nanoparticles (AgNPs) have indicated them to be promising antimicrobial agents. In the present study, extracellular extract of an endophytic bacterium, Pantoea ananatis, was used for synthesis of AgNPs. The synthesized AgNPs were characterized by UV–Vis spectroscopy, FTIR, transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and Zeta potential. The antimicrobial potential of the AgNPs against pathogenic Staphylococcus aureus subsp. aureus (ATCC 11632), Bacillus cereus (ATCC 10876), Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231), and multidrug resistant (MDR) Streptococcus pneumoniae (ATCC 700677), Enterococcus faecium (ATCC 700221) Staphylococcus aureus (ATCC 33592) Escherichia coli (NCTC 13351) was investigated. The synthesized spherical-shaped AgNPs with a size range of 8.06 nm to 91.32 nm exhibited significant antimicrobial activity at 6 μg/disc concentration against Bacillus cereus (ATCC 10876) and Candida albicans (ATCC 10231) which were found to be resistant to conventional antibiotics. The synthesized AgNPs showed promising antibacterial efficiency at 10 µg/disc concentration against the MDR strains. The present study suggests that AgNPs synthesized by using the endophytic bacterium P. ananatis are promising antimicrobial agent.

scholarly journals Antioxidant and DNA Damage Protecting Activity of Exopolysaccharides from the Endophytic Bacterium Bacillus cereus SZ1

Molecules ◽  
2016 ◽  
Vol 21 (2) ◽  
pp. 174 ◽  
Author(s):  
Li Zheng ◽  
Tin Zou ◽  
Yan Ma ◽  
Jian Wang ◽  
Yu Zhang
Keyword(s):  
Dna Damage ◽  
Bacillus Cereus ◽  
Endophytic Bacterium ◽  
Bacterium Bacillus

scholarly journals Production of biopolyester poly(3-hydroxybutyrate) by Bacillus cereus RCL 02, a leaf endophyte of Ricinus communis L.

2017 ◽  
Vol 7 (4) ◽  
pp. 32 ◽  
Author(s):  
Rituparna Das ◽  
Arundhati Pal ◽  
Amal K. Paul
Keyword(s):  
Bacillus Cereus ◽  
Endophytic Bacteria ◽  
Ricinus Communis ◽  
Carbon Sources ◽  
Dry Weight ◽  
Mineral Salts ◽  
Scientific Communities ◽  
Biodegradable Polyesters ◽  
Ricinus Communis L ◽  
Bacterium Bacillus

Endophytic bacteria colonizing the internal tissues of plants have attracted the attention of scientific communities in recent years for production of biodegradable polyesters like polyhydroxyalkanotaes (PHAs). A newly characterized bacterium, Bacillus cereus RCL 02 (GenBank accession no. KX458035), isolated from surface sterilized leaves of Ricinus communis L. has been explored for the production of poly(3-hydroxybutyrate) [P(3HB)], the most common PHA. As revealed by scanning electron microscopy, P(3HB) accumulating cells developed swellings or blebs and released the native granules as a function of autolysis. During growth in glucose containing mineral salts medium under batch fermentation, the isolate produced P(3HB) accounting 68% of its cell dry weight (CDW). Glucose and yeast extract when used in the ratio of 5:1, significantly influenced intracellular biopolyester accumulation (72.2%, CDW and 2.54 g/L). A further increase of polymer production (81%, CDW and 3.17 g/L) was accomplished in presence of 1.5 mM manganese as exogenous metal stress. Moreover, supplementation of the growth medium with non-conventional carbon sources especially refined sugarcane molasses further enhanced the production of both biomass (9.44 g/L) as well as polyester (83.6%, CDW and 7.89 g/L). These finding emphasises exploration of endophytic bacteria of oleaginous plants in general and R. communis L. in particular as potential but hitherto an under exploited bioresource for commercial production of biodegradable polyesters.

Immobilization of Uranium at Nanoscale by Bacillus cereus 12-2 at Different U(VI) Concentration

2019 ◽  
Vol 19 (11) ◽  
pp. 7131-7138
Author(s):  
Jian Zhang ◽  
Hongxin Chen ◽  
Jianning Song ◽  
Hong Deng ◽  
Zhi Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bacillus Cereus ◽  
Functional Groups ◽  
Adsorption Equilibrium ◽  
Uranium Concentration ◽  
Removal Rate ◽  
Dry Weight ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Time Required

Uranium can be immobilized as nanoscale minerals by biomineralization under aerobic conditions. Current researches on nonreductive biomineralization of U(VI) mainly focus on revealing the mechanisms associated with functional groups and enzymes. However, studies on the effect of initial uranium concentration on the uranium bio-immobilization are relatively rare. This paper researched the immobilization of U(VI) at different concentrations by Bacillus cereus 12-2. Adsorption experiments showed that the adsorption equilibrium was rapidly reached within 10 min when U(VI) concentration was 25 mg/L while over 2 h when U(VI) concentration was 200 mg/L. The biological adsorption capacity improved gradually from 24.68 to 163.17 mg/g (dry weight) as U(VI) concentration increased, but the removal rate of uranium decreased from about 100% to 80%. X-ray diffraction (XRD) showed that nanoscale uramphite ((NH4)(UO2)PO4·3H2O) formation time was 4, 4, 12 and 24 h, respectively when initial U(VI) concentration was 25, 50, 75 and 100 mg/L. No mineral was formed after reaction for 24 h when U(VI) concentration was 200 mg/L. Uramphite had better peaks in spectrum after 50 mg/L U(VI) had interacted with Bacillus cereus 12-2 for 4 h. XRD, SEM (scanning electron microscopy) and TEM (transmission electron microscopy) indicated that a large number of amorphous uranium-containing particles appeared extracellularly after 10 min and nanoscale uramphite formed intracellularly after 4 h when uranium concentration was 50 mg/L. This study showed that the time required for adsorption equilibrium and mineralization by Bacillus cereus 12-2 was shorter when the initial U(VI) concentration was lower within a certain range. This phenomenon could be attributed to the increase of relative content of functional groups and the decrease of cytotoxicity of uranium at low concentrations. This work had certain guiding significance for further understanding the mechanism of uranium biomineralization and the application of Bacillus cereus 12-2 under actual uranium-contaminated environments.

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