-
Nanoscale Research Letters May 2018Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the... (Review)
Review
Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the UVA and UVB region of spectra due to wide bandgap. Impact of zinc oxide on biological functions depends on its morphology, particle size, exposure time, concentration, pH, and biocompatibility. They are more effective against microorganisms such as Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Sarcina lutea, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Pseudomonas vulgaris, Candida albicans, and Aspergillus niger. Mechanism of action has been ascribed to the activation of zinc oxide nanoparticles by light, which penetrate the bacterial cell wall via diffusion. It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.
PubMed: 29740719
DOI: 10.1186/s11671-018-2532-3 -
Frontiers in Microbiology 2021Bacterial metabolites exhibit a variety of biologically active compounds including antibacterial and antifungal activities. It is well known that is considered to be a...
Bacterial metabolites exhibit a variety of biologically active compounds including antibacterial and antifungal activities. It is well known that is considered to be a promising source of bioactive secondary metabolites. Most plant pathogens have an incredible ability to mutate and acquire resistance, causing major economic losses in the agricultural field. Therefore, it is necessary to use the natural antibacterial compounds in microbes to control plant pathogens. This study was conducted to investigate the bio-active compounds of L2. According to the activity guidance of T-37, EC-1 and RS-2, five monomeric compounds, including erucamide (), behenic acid (), palmitic acid (), phenylacetic acid (), and β-sitosterol (), were fractionated and purified from the crude ethyl acetate extract of . To our knowledge, all compounds were isolated from the bacterium for the first time. To understand the antimicrobial activity of these compounds, and their minimum inhibitory concentrations (MICs) (range: 0.98∼500 μg/mL) were determined by the broth microdilution method. For the three tested pathogens, palmitic acid exhibited almost no antibacterial activity (>500 μg/mL), while erucamide had moderate antibacterial activity (MIC = 500 μg/mL). Behenic acid showed MICs of 250 μg/mL against T-37 and RS-2 strains with an antibacterial activity. β-sitosterol showed significant antimicrobial activity against RS-2. β-sitosterol showed remarkable antimicrobial activity against RS-2 with an MIC of 15.6 μg/mL. In addition, with the antimicrobial activity, against T-37 (62.5 μg/mL) and against EC-1 (125 μg/mL) and RS-2 (15.6 μg/mL) strains notably, phenylacetic acid may be interesting for the prevention and control of phytopathogenic bacteria. Our findings suggest that isolated compounds such as behenic acid, β-sitosterol, and phenylacetic acid may be promising candidates for natural antimicrobial agents.
PubMed: 33841370
DOI: 10.3389/fmicb.2021.645484 -
PeerJ 2018Next-Generation Sequencing (NGS) technologies provide unique possibilities for the comprehensive assessment of the environmental diversity of bacteriophages. Several...
Next-Generation Sequencing (NGS) technologies provide unique possibilities for the comprehensive assessment of the environmental diversity of bacteriophages. Several bacteriophages have been isolated, but very few bacteriophages have been characterized. In this study, we describe the biological characteristics, whole genome sequences, and annotations for two new isolates of the bacteriophages (BM5 and BM10), which were isolated from Egyptian soil samples. Growth analyses indicated that the phages BM5 and BM10 have a shorter latent period (25 and 30 min, respectively) and a smaller burst size (103 and 117 PFU, respectively), in comparison to what is typical for phages. The genome sizes of the phages BM5 and BM10 were 165,031 bp and 165,213 bp, respectively, with modular organization. Bioinformatic analyses of these genomes enabled the assignment of putative functions to 97 and 65 putative ORFs, respectively. Comparative analysis of the BM5 and BM10 genome structures, in conjunction with other bacteriophages, revealed relatively high levels of sequence and organizational identity. Both genomic comparisons and phylogenetic analyses support the conclusion that the sequenced phages (BM5 and BM10) belong to different sub-clusters (L5 and L7, respectively), within the L-cluster, and display different lifestyles (lysogenic and lytic, respectively). Moreover, sequenced phages encode proteins associated with pathogenesis. In addition, BM5 does not contain any tRNA sequences, whereas BM10 genome codes for 17 tRNAs.
PubMed: 30581654
DOI: 10.7717/peerj.5687 -
Applied Microbiology and Biotechnology Aug 2021Over 30 years, the Gram-positive bacterium Priestia megaterium (previously known as Bacillus megaterium) was systematically developed for biotechnological applications... (Review)
Review
Over 30 years, the Gram-positive bacterium Priestia megaterium (previously known as Bacillus megaterium) was systematically developed for biotechnological applications ranging from the production of small molecules like vitamin B, over polymers like polyhydroxybutyrate (PHB) up to the in vivo and in vitro synthesis of multiple proteins and finally whole-cell applications. Here we describe the use of the natural vitamin B (cobalamin) producer P. megaterium for the elucidation of the biosynthetic pathway and the subsequent systematic knowledge-based development for production purposes. The formation of PHB, a natural product of P. megaterium and potential petro-plastic substitute, is covered and discussed. Further important biotechnological characteristics of P. megaterium for recombinant protein production including high protein secretion capacity and simple cultivation on value-added carbon sources are outlined. This includes the advanced system with almost 30 commercially available expression vectors for the intracellular and extracellular production of recombinant proteins at the g/L scale. We also revealed a novel P. megaterium transcription-translation system as a complementary and versatile biotechnological tool kit. As an impressive biotechnology application, the formation of various cytochrome P450 is also critically highlighted. Finally, whole cellular applications in plant protection are completing the overall picture of P. megaterium as a versatile giant cell factory. KEY POINTS: • The use of Priestia megaterium for the biosynthesis of small molecules and recombinant proteins through to whole-cell applications is reviewed. • P. megaterium can act as a promising alternative host in biotechnological production processes.
Topics: Bacillus megaterium; Beauty; Biotechnology; Recombinant Proteins; Vitamin B 12
PubMed: 34263356
DOI: 10.1007/s00253-021-11424-6 -
Molecules (Basel, Switzerland) Nov 2018Microbial solubilization applies the natural ability of a microorganism to liberate phosphorus from unavailable structures. The main mechanism recognized to be...
Microbial solubilization applies the natural ability of a microorganism to liberate phosphorus from unavailable structures. The main mechanism recognized to be responsible for the solubilization of phosphorus is the production of different types of organic acids. Three kinds of species and three types of raw materials (poultry bones, fish bones, and ash) were tested for solubilization. The following parameters were compared for all discussed cases: pH, specific growth rate, solubilization factor, released phosphorus concentration, and total and individual concentration of organic acids. Utilization of ash brought about the highest specific and maximum specific growth rates. A decrease in pH was observed in most of the discussed cases with the exception of fish bones. At the same time, fish bones had the highest concentration of released P₂O₅ and the highest total concentration of produced organic acids (gluconic, lactic, acetic, succinic, and propionic) in all discussed cases. The tested species produced the mentioned acids with the exception of , where propionic acid was not present. The lactic and acetic acids were those produced in the highest amount. The kind of raw materials and type of species used in solubilization had a strong influence on the kind of organic acids that were detected in the broth culture and its total concentration, which had a direct influence on the amount of released phosphorus. The combination of with the fish bones at 5 g/L is proposed as the pair that gives the highest concentration of released phosphorus (483 ± 5 mg/L).
Topics: Bacillus; Bacillus cereus; Bacillus megaterium; Bacillus subtilis; Phosphorus; Solubility
PubMed: 30404208
DOI: 10.3390/molecules23112897 -
Microbiology Spectrum Oct 2022The environmental deterioration produced by heavy metals derived from anthropogenic activities has gradually increased. The worldwide dissemination of toxic metals in...
The environmental deterioration produced by heavy metals derived from anthropogenic activities has gradually increased. The worldwide dissemination of toxic metals in crop soils represents a threat for sustainability and biosafety in agriculture and requires strategies for the recovery of metal-polluted crop soils. The biorestoration of metal-polluted soils using technologies that combine plants and microorganisms has gained attention in recent decades due to the beneficial and synergistic effects produced by its biotic interactions. In this context, native and heavy metal-resistant plant growth-promoting bacteria (PGPB) play a crucial role in the development of strategies for sustainable biorestoration of metal-contaminated soils. In this study, we present a genomic analysis and characterization of the rhizospheric bacterium Bacillus megaterium HgT21 isolated from metal-polluted soil from Zacatecas, Mexico. The results reveal that this autochthonous bacterium contains an important set of genes related to a variety of operons associated with mercury, arsenic, copper, cobalt, cadmium, zinc and aluminum resistance. Additionally, halotolerance-, beta-lactam resistance-, phosphate solubilization-, and plant growth-promotion-related genes were identified. The analysis of resistance to metal ions revealed resistance to mercury (Hg), arsenate [AsO]³, cobalt (Co), zinc (Zn), and copper (Cu). Moreover, the ability of the HgT21 strain to produce indole acetic acid (a phytohormone) and promote the growth of Arabidopsis thaliana seedlings was also demonstrated. The genotype and phenotype of Bacillus megaterium HgT21 reveal its potential to be used as a model of both plant growth-promoting and metal multiresistant bacteria. Metal-polluted environments are natural sources of a wide variety of PGPB adapted to cope with toxic metal concentrations. In this work, the bacterial strain Bacillus megaterium HgT21 was isolated from metal-contaminated soil and is proposed as a model for the study of metal multiresistance in spore-forming Gram-positive bacteria due to the presence of a variety of metal resistance-associated genes similar to those encountered in the metal multiresistant Gram-negative Cupriavidus metallidurans CH34. The ability of B. megaterium HgT21 to promote the growth of plants also makes it suitable for the study of plant-bacteria interactions in metal-polluted environments, which is key for the development of techniques for the biorestoration of metal-contaminated soils used for agriculture.
Topics: Soil; Bacillus megaterium; Cadmium; Soil Pollutants; Arsenates; Biodegradation, Environmental; Copper; Plant Growth Regulators; Arsenic; Aluminum; Metals, Heavy; Soil Microbiology; Zinc; Mercury; Cobalt; Phosphates
PubMed: 35980185
DOI: 10.1128/spectrum.00656-22 -
Plants (Basel, Switzerland) Oct 2021The present study demonstrates the Ni toxicity-ameliorating and growth-promoting abilities of two different bacterial isolates when applied to wheat ( L.) as the host...
The present study demonstrates the Ni toxicity-ameliorating and growth-promoting abilities of two different bacterial isolates when applied to wheat ( L.) as the host plant. Two bacterial strains tolerant to Ni stress were isolated from wheat seeds and selected based on their ability to improve the germination of wheat plants; they were identified as AFI1 and AFI2. The protective effects of these epiphytic bacteria against Ni stress were studied in model experiments with two wheat cultivars: Ni stress-tolerant Leningradskaya 6 and susceptible Chinese spring. When these isolates were used as the inoculants applied to Ni-treated wheat plants, the growth parameters and the levels of photosynthetic pigments of the two wheat cultivars both under normal and Ni-stress conditions were increased, though AFI1 had a more pronounced ameliorative effect on the Ni contents in plant tissues due to its synthesis of siderophores. Over the 10 days of Ni exposure, the plant growth promotion bacteria (PGPB) significantly reduced the lipid peroxidation (LPO), ascorbate peroxidase (APX), superoxide dismutase (SOD) activities and proline content in the leaves of both wheat cultivars. The PGPB also increased peroxidase (POX) activity and the levels of chlorophyll , chlorophyll , and carotenoids in the wheat leaves. It was concluded that AFI1 is an ideal candidate for bioremediation and wheat growth promotion against Ni-induced oxidative stress, as it increases photosynthetic pigment contents, induces the antioxidant defense system, and lowers Ni metal uptake.
PubMed: 34834698
DOI: 10.3390/plants10112334 -
International Journal of Molecular... Mar 2024is particularly known for its abundance in soils and its plant growth promotion. To characterize the metabolites excreted by this specie, we performed successive...
is particularly known for its abundance in soils and its plant growth promotion. To characterize the metabolites excreted by this specie, we performed successive liquid/liquid extractions from bacteria culture medium with different polarity solvents (cyclohexane, dichloromethane, ethyl acetate and butanol) to separate the metabolites in different polarity groups. The extracts were characterized regarding their total phenolic content, the amount of reducing sugar, the concentration of primary amines and proteins, their chromatographic profile by HPLC-DAD-ELSD and their chemical identification by GC-MS. Among the 75 compounds which are produced by the bacteria, 19 identifications were for the first time found as metabolites of and 23 were described for the first time as metabolites in genus. The different extracts containing metabolites showed interesting agronomic activity, with a global inhibition of seed germination rates of soya, sunflower, corn and ray grass, but not of corn, compared to culture medium alone. Our results suggest that can produce various metabolites, like butanediol, cyclic dipeptides, fatty acids, and hydrocarbons, with diverse effects and sometimes with opposite effects in order to modulate its response to plant growth and adapt to various environmental effects. These findings provide new insight into bioactive properties of this species for therapeutic uses on plants.
Topics: Bacillus megaterium; Antioxidants; Gas Chromatography-Mass Spectrometry
PubMed: 38542209
DOI: 10.3390/ijms25063235 -
Journal of Bacteriology Jun 2021Spores of firmicute species contain 100s of mRNAs, whose major function in Bacillus subtilis is to provide ribonucleotides for new RNA synthesis when spores germinate....
Spores of firmicute species contain 100s of mRNAs, whose major function in Bacillus subtilis is to provide ribonucleotides for new RNA synthesis when spores germinate. To determine if this is a general phenomenon, RNA was isolated from spores of multiple firmicute species and relative mRNA levels determined by transcriptome sequencing (RNA-seq). Determination of RNA levels in single spores allowed calculation of RNA nucleotides/spore, and assuming mRNA is 3% of spore RNA indicated that only ∼6% of spore mRNAs were present at >1/spore. Bacillus subtilis, Bacillus atrophaeus, and Clostridioides difficile spores had 49, 42, and 51 mRNAs at >1/spore, and numbers of mRNAs at ≥1/spore were ∼10 to 50% higher in Geobacillus stearothermophilus and Bacillus thuringiensis Al Hakam spores and ∼4-fold higher in Bacillus megaterium spores. In all species, some to many abundant spore mRNAs (i) were transcribed by RNA polymerase with forespore-specific σ factors, (ii) encoded proteins that were homologs of those encoded by abundant B. subtilis spore mRNAs and are proteins in dormant spores, and (iii) were likely transcribed in the mother cell compartment of the sporulating cell. Analysis of the coverage of RNA-seq reads on mRNAs from all species suggested that abundant spore mRNAs were fragmented, as was confirmed by reverse transcriptase quantitative PCR (RT-qPCR) analysis of abundant B. subtilis and C. difficile spore mRNAs. These data add to evidence indicating that the function of at least the great majority of mRNAs in all firmicute spores is to be degraded to generate ribonucleotides for new RNA synthesis when spores germinate. Only ∼6% of mRNAs in spores of six firmicute species are at ≥1 molecule/spore, many abundant spore mRNAs encode proteins similar to B. subtilis spore proteins, and some abundant B. subtilis and C. difficile spore mRNAs were fragmented. Most of the abundant B. subtilis and other spore mRNAs are transcribed under the control of the forespore-specific RNA polymerase σ factors, F or G, and these results may stimulate transcription analyses in developing spores of species other than B. subtilis. These findings, plus the absence of key nucleotide biosynthetic enzymes in spores, suggest that firmicute spores' abundant mRNAs are not translated when spores germinate but instead are degraded to generate ribonucleotides for new RNA synthesis by the germinated spore.
Topics: Bacterial Proteins; DNA-Directed RNA Polymerases; Firmicutes; RNA, Bacterial; RNA, Messenger; Spores, Bacterial
PubMed: 33972352
DOI: 10.1128/JB.00017-21 -
Polimery W Medycynie 2021Gamma-polyglutamic acid (γ-PGA) is a microbially produced non-toxic peptide biopolymer which is gaining grounds in many biotechnological fields and has a wide range of...
BACKGROUND
Gamma-polyglutamic acid (γ-PGA) is a microbially produced non-toxic peptide biopolymer which is gaining grounds in many biotechnological fields and has a wide range of applications.
OBJECTIVES
In this study, the characteristics of γ-PGA produced by Bacillus megaterium isolated from an oil seed were determined, while the nutritional requirements of the bacterium were optimized using a predictive 15 factor-16 run Plackett-Burman experimental design.
MATERIAL AND METHODS
The main effect of each factor, the interaction and quadratic effects of the factors on optimized production were determined from Box-Benkhen model using Dell Statistica v. 12 and 13 software. Bacillus megaterium UP47 produced the highest γ-PGA (16.33 g/L) out of 56 spore-forming Bacillus strains isolated from soil, water and fermented food samples.
RESULTS
Hydrolysates of the produced γ-PGA had a retention factor which corresponded to the L-glutamic acid standard (retention factor (rf) 0.35), while high-definition fourier transform infrared (FT-IR) spectroscopic imaging showed characteristic peaks representative of the active bonds present in γ-PGA. The γ-PGA at a concentration as low as 50 mg/100 mL exerted antimicrobial inhibitions against test pathogens. A 2.00 w/v γ-PGA solution had 11 mm and 13 mm inhibition zones against Staphylococcus aureus and Shigella dysenteriae, respectively. A second order polynomial equation for prediction of γ-PGA was derived as: γPGA yield = 3316.061 - 449.708A + 9.036A2 - 139.813B + 3.095B2 - 7.699C - 0.164C2 + 13.116AB - 0.087AB2 - 0.248A2B + 3.781AC - 0.076A2C - 0.394BC. It showed an increase in γ-PGA yield with increasing L-glutamic acid and biotin, but a decrease with yeast extract.
CONCLUSIONS
Bacillus megaterium UP47 had a maximum γ-PGA yield of 54 g/L and 62 g/L, respectively, from the Plackett-Burman and Box-Benkhen design, thereby resulting in an appreciable increase in polymer yield after the optimization process with a 95% confidence level.
Topics: Bacillus megaterium; Biotechnology; Polyglutamic Acid; Spectroscopy, Fourier Transform Infrared
PubMed: 34910388
DOI: 10.17219/pim/143975