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ACS Infectious Diseases Apr 2024The polymyxins are nonribosomal lipopeptides produced by and are potent antibiotics with activity specifically directed against Gram-negative bacteria. While the... (Review)
Review
The polymyxins are nonribosomal lipopeptides produced by and are potent antibiotics with activity specifically directed against Gram-negative bacteria. While the clinical use of polymyxins has historically been limited due to their toxicity, their use is on the rise given the lack of alternative treatment options for infections due to multidrug resistant Gram-negative pathogens. The Gram-negative specificity of the polymyxins is due to their ability to target lipid A, the membrane embedded LPS anchor that decorates the cell surface of Gram-negative bacteria. Notably, the mechanisms responsible for polymyxin toxicity, and in particular their nephrotoxicity, are only partially understood with most insights coming from studies carried out in the past decade. In parallel, many synthetic and semisynthetic polymyxin analogues have been developed in recent years in an attempt to mitigate the nephrotoxicity of the natural products. Despite these efforts, to date, no polymyxin analogues have gained clinical approval. This may soon change, however, as at the moment there are three novel polymyxin analogues in clinical trials. In this context, this review provides an update of the most recent insights with regard to the structure-activity relationships and nephrotoxicity of new polymyxin variants reported since 2010. We also discuss advances in the synthetic methods used to generate new polymyxin analogues, both via total synthesis and semisynthesis.
Topics: Anti-Bacterial Agents; Polymyxins; Lipopeptides; Gram-Negative Bacteria; Structure-Activity Relationship
PubMed: 38470446
DOI: 10.1021/acsinfecdis.3c00630 -
Methods in Molecular Biology (Clifton,... 2024In recent years, the clustered regularly interspaced palindromic repeats-Cas (CRISPR-Cas) technology has become the method of choice for precision genome editing in many...
In recent years, the clustered regularly interspaced palindromic repeats-Cas (CRISPR-Cas) technology has become the method of choice for precision genome editing in many organisms due to its simplicity and efficacy. Multiplex genome editing, point mutations, and large genomic modifications are attractive features of the CRISPR-Cas9 system. These applications facilitate both the ease and velocity of genetic manipulations and the discovery of novel functions. In this protocol chapter, we describe the use of a CRISPR-Cas9 system for multiplex integration and deletion modifications, and deletions of large genomic regions by the use of a single guide RNA (sgRNA), and, finally, targeted point mutation modifications in Paenibacillus polymyxa.
Topics: Gene Editing; CRISPR-Cas Systems; RNA, Guide, CRISPR-Cas Systems; Paenibacillus polymyxa; Genome
PubMed: 38468094
DOI: 10.1007/978-1-0716-3658-9_16 -
IScience Mar 2024Azasugars, such as 1-deoxynojirimycin (1-DNJ), exhibit unique physiological functions and hold promising applications in medicine and health fields. However, the...
Azasugars, such as 1-deoxynojirimycin (1-DNJ), exhibit unique physiological functions and hold promising applications in medicine and health fields. However, the biosynthesis of 1-DNJ is hindered by the low activity and thermostability of the transaminase. In this study, the transaminase from (MvTA) with activity toward d-fructose was engineered through semi-rational design and high-throughput screening method. The final mutant M9-1 demonstrated a remarkable 31.2-fold increase in specific activity and an impressive 200-fold improvement in thermostability compared to the wild-type enzyme. Molecular dynamics (MD) simulations revealed that the mutation sites of H69R and K145R in M9-1 played crucial roles in the binding of the amino acceptor and donor, leading to the stable conformation of substrates within the active pocket. An enzyme cascade reaction was developed using M9-1 and the dehydrogenase from (GutB1) for the production of mannojirimycin (MJ), which provided a new idea for the biosynthesis of 1-DNJ.
PubMed: 38433920
DOI: 10.1016/j.isci.2024.109034 -
International Journal of Molecular... Feb 2024Screening of with antagonistic effects on paddy mold pathogens to provide strain resources for biological control of mold in L. screening of isolates antagonistic...
Screening of with antagonistic effects on paddy mold pathogens to provide strain resources for biological control of mold in L. screening of isolates antagonistic towards from rhizosphere soil of healthy paddy; classification and identification of antagonistic strains by biological characteristics and 16S rDNA sequence analysis; transcriptome sequencing after RNA extraction from Bacillus-treated ; and extraction of inhibitory crude proteins of by ammonium sulfate precipitation; inhibitory crude protein and spp. were treated separately for and observed by scanning electron microscopy (SEM). An antagonistic strain of , named B7, was identified as by 16S rDNA identification and phylogenetic evolutionary tree comparison analysis. Analysis of the transcriptome results showed that genes related to secondary metabolite biosynthesis such as antifungal protein were significantly downregulated. SEM results showed that the mycelium of underwent severe rupture after treatment with and antifungal proteins, respectively. In addition, the sporocarp changed less after treatment with , and the sporangium stalks had obvious folds. B7 has a good antagonistic effect against and has potential for biocontrol applications of paddy mold pathogens.
Topics: Paenibacillus polymyxa; Antifungal Agents; Phylogeny; Antibiosis; Bacillus; DNA, Ribosomal; Paenibacillus; Aspergillus
PubMed: 38396880
DOI: 10.3390/ijms25042195 -
International Journal of Biological... Apr 2024Clubroot, caused by the obligate parasite Plasmodiophora brassicae, is one of the most important diseases of brassicas. The antagonistic bacterium Paenibacillus polymyxa...
Clubroot, caused by the obligate parasite Plasmodiophora brassicae, is one of the most important diseases of brassicas. The antagonistic bacterium Paenibacillus polymyxa ZF129 can suppress clubroot while its effectiveness is often unstable. To control clubroot more effectively, the macrobeads for controlled release of ZF129 were prepared using microencapsulation technology. Macrobeads with various ratios of chitosan (2 % w/w): carrageenan (0.3 % w/v) were prepared by an ionotropic gelation method and the bacteria ZF129 was loaded into macrobeads. The 1:1 chitosan: carrageenan showed the maximum swelling ratio (634 %), and the maximum survival rate (61.52 ± 1.12 %) after freeze-drying. Fourier transform infrared revealed the electrostatic interactions between chitosan and carrageenan. The macrobeads can efficiently release ZF129 strains into phosphate buffer solution and reach equilibrium in 48 h. The maximum number of bacteria cells to be released in the soil was observed after 25-30 days. The control efficacy of ZF129 macrobeads (chitosan: carrageenan, 1:1) and ZF129 culture against clubroot disease was 76.33 ± 3.65 % and 59.76 ± 4.43 % in greenhouse experiments, respectively and the control efficacy was calculated as 60.74 ± 5.00 % for ZF129 macrobeads and 40.94 ± 4.05 % for ZF129 culture under field experiments, respectively. The ZF129 macrobeads had significant growth-promoting effects on pak choi and Chinese cabbage. The encapsulation method described in this study is a prudent approach toward efficient biopesticides utilization with reduced environmental implications.
Topics: Brassica; Carrageenan; Chitosan; Paenibacillus polymyxa; Crops, Agricultural
PubMed: 38387628
DOI: 10.1016/j.ijbiomac.2024.130323 -
Microbiological Research May 2024Soil salinity negatively affects microbial communities, soil fertility, and agricultural productivity and has become a major agricultural problem worldwide. Plant...
Soil salinity negatively affects microbial communities, soil fertility, and agricultural productivity and has become a major agricultural problem worldwide. Plant growth-promoting rhizobacteria (PGPR) with salt tolerance can benefit plant growth under saline conditions and diminish the negative effects of salt stress on plants. In this study, we aimed to understand the salt-tolerance mechanism of Paenibacillus polymyxa at the genetic and metabolic levels and elucidate the mechanism of strain SC2 in promoting maize growth under saline conditions. Under salt stress, we found that strain SC2 promoted maize seedling growth, which was accompanied by a significant upregulation of genes encoding for the biosynthesis of peptidoglycan, polysaccharide, and fatty acid, the metabolism of purine and pyrimidine, and the transport of osmoprotectants such as trehalose, glycine betaine, and K in strain SC2. To further enhance the salt resistance of strain SC2, three mutants (SC2-11, SC2-13, and SC2-14) with higher capacities for salt resistance and exopolysaccharide synthesis were obtained via atmospheric and room-temperature plasma mutagenesis. In saline-alkaline soil, the mutants showed better promoting effect on maize seedlings than wild-type SC2. The fresh weight of maize seedlings was increased by 68.10% after treatment with SC2-11 compared with that of the control group. The transcriptome analysis of maize roots demonstrated that SC2 and SC2-11 could induce the upregulation of genes related to the plant hormone signal transduction, starch and sucrose metabolism, reactive oxygen species scavenging, and auxin and ethylene signaling under saline-alkaline stress. In addition, various transcription factors, such as zinc finger proteins, ethylene-responsive-element-binding protein, WRKY, myeloblastosis proteins, basic helix-loop-helix proteins, and NAC proteins, were up-regulated in response to abiotic stress. Moreover, the microbial community composition of maize rhizosphere soil after inoculating with strain SC2 was varied from the one after inoculating with mutant SC2-11. Our results provide new insights into the various genes involved in the salt resistance of strain SC2 and a theoretical basis for utilizing P. polymyxa in saline-alkaline environments.
Topics: Seedlings; Paenibacillus polymyxa; Zea mays; Soil; Ethylenes
PubMed: 38354626
DOI: 10.1016/j.micres.2024.127639 -
Synthetic and Systems Biotechnology Mar 2024Polymyxin B, produced by is used as the last line of defense clinically. In this study, exogenous mixture of precursor amino acids increased the level and proportion of...
Polymyxin B, produced by is used as the last line of defense clinically. In this study, exogenous mixture of precursor amino acids increased the level and proportion of polymyxin B1 in the total of polymyxin B analogs of CJX518-AC (PPAC) from 0.15 g/L and 61.8 % to 0.33 g/L and 79.9 %, respectively. The co-culture of strain PPAC and recombinant -leu01, which produces high levels of threonine, leucine, and isoleucine, increased polymyxin B1 production to 0.64 g/L. When strains PPAC and -leu01 simultaneously inoculated into an optimized medium with 20 g/L peptone, polymyxin B1 production was increased to 0.97 g/L. Furthermore, the polymyxin B1 production in the co-culture of strains PPAC and -leu01 increased to 2.21 g/L after optimized inoculation ratios and fermentation medium with 60 g/L peptone. This study provides a new strategy to improve polymyxin B1 production.
PubMed: 38348399
DOI: 10.1016/j.synbio.2024.01.015 -
ACS Synthetic Biology Feb 2024The use of as an industrial producer is limited by the lack of suitable synthetic biology tools. In this study, we identified a native sucrose operon in . Its...
The use of as an industrial producer is limited by the lack of suitable synthetic biology tools. In this study, we identified a native sucrose operon in . Its structural and functional relationship analysis revealed the presence of multiple regulatory elements, including four ScrR-binding sites and a catabolite-responsive element (CRE). In , we established a cascade T7 expression system involving an integrated () regulated by the sucrose operon and a T7 promoter. It enables controllable gene expression by sucrose and regulatory elements, and a 5-fold increase in expression efficiency compared with the original sucrose operon was achieved. Further deletion of SacB in resulted in a 38.95% increase in the level of thermophilic lipase (TrLip) production using the cascade T7 induction system. The results highlight the effectiveness of sucrose regulation as a novel synthetic biology tool, which facilitates exploring gene circuits and enables their dynamic regulation.
Topics: Paenibacillus polymyxa; Sucrose; Promoter Regions, Genetic; Operon
PubMed: 38319655
DOI: 10.1021/acssynbio.3c00689 -
Scientific Reports Jan 2024Accurate identification and typing of microbes are crucial steps in gaining an awareness of the biological heterogeneity and reliability of microbial material within any...
Accurate identification and typing of microbes are crucial steps in gaining an awareness of the biological heterogeneity and reliability of microbial material within any proprietary or public collection. Paenibacillus polymyxa is a bacterial species of great agricultural and industrial importance due to its plant growth-promoting activities and production of several relevant secondary metabolites. In recent years, matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) has been widely used as an alternative rapid tool for identifying, typing, and differentiating closely related strains. In this study, we investigated the diversity of three P. polymyxa strains. The mass spectra of ATCC 842, DSM 292, and DSM 365 were obtained, analysed, and compared to select discriminant peaks using ClinProTools software and generate classification models. MALDI-TOF MS analysis showed inconsistent results in identifying DSM 292 and DSM 365 as belonging to P. polimixa species, and comparative analysis of mass spectra revealed the presence of highly discriminatory biomarkers among the three strains. 16S rRNA sequencing and Average Nucleotide Identity (ANI) confirmed the discrepancies found in the proteomic analysis. The case study presented here suggests the enormous potential of the proteomic-based approach, combined with statistical tools, to predict and explore differences between closely related strains in large microbial datasets.
Topics: Paenibacillus polymyxa; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Proteomics; RNA, Ribosomal, 16S; Reproducibility of Results
PubMed: 38297004
DOI: 10.1038/s41598-023-50010-w -
International Journal of Biological... Mar 2024Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of... (Review)
Review
Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of many metabolically active substances, including polypeptides, volatile organic compounds, phytohormone, hydrolytic enzymes, exopolysaccharide (EPS), etc. Due to the wide range of compounds that it produces, P. polymyxa has been extensively studied as a plant growth promoting bacterium which provides a direct benefit to plants through the improvement of N fixation from the atmosphere and enhancement of the solubilization of phosphorus and the uptake of iron in the soil, and phytohormones production. Among the metabolites from P. polymyxa, EPS exhibits many activities, for example, antioxidant, immunomodulating, anti-tumor and many others. EPS has various applications in food, agriculture, environmental protection. Particularly, in the field of sustainable agriculture, P. polymyxa EPS can be served as a biofilm to colonize microbes, and also can act as a nutrient sink on the roots of plants in the rhizosphere. Therefore, this paper would provide a comprehensive review of the advancements of diverse aspects of EPS from P. polymyxa, including the production, extraction, structure, biosynthesis, bioactivity and applications, etc. It would provide a direction for future research on P. polymyxa EPS.
Topics: Paenibacillus polymyxa; Paenibacillus; Plant Growth Regulators; Plant Development; Plants
PubMed: 38278396
DOI: 10.1016/j.ijbiomac.2024.129663