-
Biology Jul 2022The use of microbial products as natural biocontrol agents to increase a plant's systemic resistance to viral infections is a promising way to make agriculture more...
The use of microbial products as natural biocontrol agents to increase a plant's systemic resistance to viral infections is a promising way to make agriculture more sustainable and less harmful to the environment. The rhizobacterium has been shown to have strong biocontrol action against plant diseases, but its antiviral activity has been little investigated. Here, the efficiency of the culture filtrate of the strain SZYM (Acc# ON149452) to protect squash ( L.) plants against a (ZYMV, Acc# ON159933) infection was evaluated. Under greenhouse conditions, the foliar application of the culture filtrate of SZYM either in protective or curative treatment conditions enhanced squash growth, reduced disease severity, and decreased ZYMV accumulation levels in the treated plants when compared to the non-treated plants. The protective treatment group exhibited the highest inhibitory effect (80%), with significant increases in their total soluble carbohydrates, total soluble protein content, ascorbic acid content, and free radical scavenging activity. Furthermore, a considerable increase in the activities of reactive oxygen species scavenging enzymes (superoxide dismutase, polyphenol oxidase, and peroxidase) were also found. In addition, the induction of systemic resistance with a significant elevation in the transcriptional levels of polyphenolic pathway genes (, , and ) and pathogenesis-related genes ( and ) was observed. Out of the 14 detected compounds in the GC-MS analysis, propanoic acid, benzenedicarboxylic acid, tetradecanoic acid, and their derivatives, as well as pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) were the primary ingredient compounds in the ethyl acetate extract of the SZYM-culture filtrate. Such compounds may act as elicitor molecules that induce systemic resistance against viral infection. Consequently, can be considered a powerful plant growth-promoting bacterium (PGPB) in agricultural applications as well as a source of bioactive compounds for sustainable disease management. As far as we know, this is the first time that has been shown to fight viruses in plants.
PubMed: 36009777
DOI: 10.3390/biology11081150 -
Insects Jul 2022Arthropods are reported to serve as vectors of transmission of pathogenic microorganisms to humans, animals, and the environment. The aims of our study were (i) to...
Arthropods are reported to serve as vectors of transmission of pathogenic microorganisms to humans, animals, and the environment. The aims of our study were (i) to identify the external bacteriota of spiders inhabiting a chicken farm and slaughterhouse and (ii) to detect antimicrobial resistance of the isolates. In total, 102 spiders of 14 species were collected from a chicken farm, slaughterhouse, and buildings located in west Slovakia in 2017. Samples were diluted in peptone buffered water, and Tryptone Soya Agar (TSA), Triple Sugar Agar (TSI), Blood Agar (BA), and Anaerobic Agar (AA) were used for inoculation. A total of 28 genera and 56 microbial species were isolated from the samples. The most abundant species were (28 isolates) and (28 isolates). The least isolated species were (one isolate), (two isolates), (two isolates), and (two isolates). There were differences in microbial composition between the samples originating from the slaughterhouse, chicken farm, and buildings. The majority of the bacterial isolates resistant to antibiotics were isolated from the chicken farm. The isolation of potentially pathogenic bacteria such as , , and spp., which possess multiple drug resistance, is of public health concern.
PubMed: 36005303
DOI: 10.3390/insects13080680 -
Foods (Basel, Switzerland) Jul 2022Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient...
Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. Preliminary data showed that paenibacillin was preferentially partitioned in foam accumulated during growth of the producer, Paenibacillus polymyxa, in aerated liquid media. This research was initiated to improve the production and recovery of paenibacillin in bioreactors by maximizing partitioning of this antimicrobial agent in the collected foam. This was completed through harvesting foam continuously during paenibacillin production, using modified bioreactor, and optimizing bioreaction conditions through response surface methodology (RSM). During initial screening, the following factors were tested using 400 mL inoculated media in 2 L bioreactors: medium (tryptic soy broth, TSB, with or without added yeast extract), airflow (0 or 0.8 L/min; LPM), stir speed (300 or 500 revolution/min; RPM), incubation temperature (30 or 36 °C), and incubation time (16 or 24 h). Results showed that airflow, time, and stir speed had significant effects (p < 0.05) on paenibacillin recovery in the collected collapsed foam (foamate). These factors were varied together to follow the path of steepest assent to maximize paenibacillin concentration. Once the local maximum was found, RSM was completed with a central composite design to fine-tune the bioreaction parameters. The optimization experiments proved that the significant parameters and their optimal conditions for paenibacillin concentration in the foam were: incubation at 30 °C for 23 h with airflow of 0.95 LPM, and agitation speed of 450 RPM. These conditions increased paenibacillin concentration, predicted by RSM, from 16 µg/mL in bioreaction without foam collection to 743 µg/mL collected in foamate. The optimized conditions also almost doubled the yield of paenibacillin measured in the foam collected from a bioreaction run (12,674 µg/400 mL bioreaction) when compared to that obtained from a run without foam collection (6400 µg/400 mL bioreaction). Results of this study could improve the feasibility of commercial production and downstream processing of paenibacillin and similar novel antimicrobial peptides. Availability of such peptides will eventually help in protecting perishable products against pathogenic and spoilage bacteria.
PubMed: 35954057
DOI: 10.3390/foods11152290 -
Biotechnology For Biofuels and... Aug 2022Paenibacillus polymyxa is a typical plant growth-promoting rhizobacterium (PGPR), and synthesis of indole-3-acetic acid (IAA) is one of the reasons for its...
BACKGROUND
Paenibacillus polymyxa is a typical plant growth-promoting rhizobacterium (PGPR), and synthesis of indole-3-acetic acid (IAA) is one of the reasons for its growth-promoting capacity. The synthetic pathways of IAA in P. polymyxa must be identified and modified.
RESULTS
P. polymyxa SC2 and its spontaneous mutant SC2-M1 could promote plant growth by directly secreting IAA. Through metabonomic and genomic analysis, the genes patA, ilvB3, and fusE in the native IPyA pathway of IAA synthesis in strain SC2-M1 were predicted. A novel strong promoter P was rationally selected, synthetically analyzed, and then evaluated on its ability to express IAA synthetic genes. Co-expression of three genes, patA, ilvB3, and fusE, increased IAA yield by 60% in strain SC2-M1. Furthermore, the heterogeneous gene iaam of the IAM pathway and two heterogeneous IPyA pathways of IAA synthesis were selected to improve the IAA yield of strain SC2-M1. The genes ELJP6_14505, ipdC, and ELJP6_00725 of the entire IPyA pathway from Enterobacter ludwigii JP6 were expressed well by promoter P in strain SC2-M1 and increased IAA yield in the engineered strain SC2-M1 from 13 to 31 μg/mL, which was an increase of 138%.
CONCLUSIONS
The results of our study help reveal and enhance the IAA synthesis pathways of P. polymyxa and its future application.
PubMed: 35953838
DOI: 10.1186/s13068-022-02181-3 -
Frontiers in Microbiology 2022Pear Valsa canker caused by is among the most destructive diseases of pear, which causes significant economic loss. The present study was developed to explore the...
Pear Valsa canker caused by is among the most destructive diseases of pear, which causes significant economic loss. The present study was developed to explore the biocontrol efficiency and underlying antagonistic mechanism of strain Nl4 against . strain Nl4, one of the 120 different endophytic bacterial strains from pear branches, exhibited strong inhibitory effects against the mycelial growth of and caused hyphal malformation. Culture filtrate derived from strain Nl4 was able to effectively suppress mycelial growth of , and was found to exhibit strong protease, cellulase and β-1, 3-glucanase activity. Through re-isolation assay, strain Nl4 was confirmed to be capable of colonizing and surviving in pear branch. Treatment with strain NI4 effectively protected against pear Valsa canker symptoms on detached pear twigs inoculated with . Moreover, strain Nl4 promoted enhanced plant growth probably through the solubilization of phosphorus. Comparative transcriptomic analyses revealed that strain NI4 was able to suppress growth in large part through the regulation of the expression of membrane- and energy metabolism-related genes in this pathogen. Further transcriptomic analyses of pear trees indicated that strain NI4 inoculation was associated with changes in the expression of genes associated with secondary metabolite biosynthesis, signal transduction, and cutin, suberine, and wax biosynthesis. Together, these data highlighted strain Nl4 as a promising biocontrol agent against pear Valsa canker and investigated the possible mechanisms of strain Nl4 on control of this devastating disease.
PubMed: 35935238
DOI: 10.3389/fmicb.2022.950742 -
Advanced Pharmaceutical Bulletin May 2022Chronic wounds have made a challenge in medical healthcare due to their biofilm infections, which reduce the penetrance of the antibacterial agents in the injury site.... (Review)
Review
Chronic wounds have made a challenge in medical healthcare due to their biofilm infections, which reduce the penetrance of the antibacterial agents in the injury site. In infected wounds, the most common bacterial strains are and . Biofilm disruption in chronic wounds is crucial in wound healing. Due to their broad-spectrum antibacterial properties and fewer side effects, anti-biofilm peptides, especially bacteriocins, are promising in the healing of chronic wounds by biofilm destruction. This study reviews the effects of antimicrobial and anti-biofilm agents, including bacteriocins and protease enzymes as a novel approach, on wound healing, along with analyzing the molecular docking between a bacterial protease and biofilm components. Among a large number of anti-biofilm bacteriocins identified up to now, seven types have been registered in the antimicrobial peptides (AMPs) database. Although it is believed that bacterial proteases are harmful in wound healing, it has recently been demonstrated that these proteases like the human serine protease, in combination with AMPs, can improve wound healing by biofilm destruction. In this work, docking results between metalloprotease from and proteins of and involved in biofilm production, showed that this bacterial protease could efficiently interact with biofilm components. Infected wound healing is an important challenge in clinical trials due to biofilm production by bacterial pathogens. Therefore, simultaneous use of proteases or anti-biofilm peptides with antimicrobial agents could be a promising method for chronic wound healing.
PubMed: 35935044
DOI: 10.34172/apb.2022.047 -
Molecules (Basel, Switzerland) Jul 2022Incubation of , , and MPI764 with the microbial 2-benzoxazolinone (BOA)-degradation-product -acetamido-phenol, produced from 2-aminophenol, led to the recently...
Incubation of , , and MPI764 with the microbial 2-benzoxazolinone (BOA)-degradation-product -acetamido-phenol, produced from 2-aminophenol, led to the recently identified -(2-hydroxy-5-nitrophenyl) acetamide, to the hitherto unknown (2-hydroxy-5-nitrosophenyl)acetamide, and to (2-hydroxy-3-nitrophenyl)acetamide. As an alternative to the formation of phenoxazinone derived from aminophenol, dimers- and trimers-transformation products have been found. Identification of the compounds was carried out by LC/HRMS and MS/MS and, for the new structure (2-hydroxy-5-nitrosophenyl)acetamide, additionally by 1D- and 2D-NMR. Incubation of microorganisms, such as the soil bacteria , MPI763, the yeast and and the plants var. L. (kohlrabi) and Col-0, with -(2-hydroxy-5-nitrophenyl) acetamide, led to its glucoside derivative as a prominent detoxification product; in the case of , this was together with the corresponding glucoside succinic acid ester. In contrast, consortium synthesized 2-acetamido-4-nitrophenyl sulfate. 1 mM bioactive -(2-hydroxy-5-nitrophenyl) acetamide elicits alterations in the expression profile of several genes. The most responsive upregulated gene was pathogen-inducible terpene synthase The bioactivity of the compound is rapidly annihilated by glucosylation.
Topics: Acetamides; Acetanilides; Arabidopsis; Glucosides; Nitrates; Pantoea; Tandem Mass Spectrometry
PubMed: 35897961
DOI: 10.3390/molecules27154786 -
Microorganisms Jun 2022Maize ( L.) is an important crop in the world and maize sheath blight damages the yield and quality greatly. In this study, an antagonist strain, which exhibited...
Maize ( L.) is an important crop in the world and maize sheath blight damages the yield and quality greatly. In this study, an antagonist strain, which exhibited antagonism against pathogenic fungi of maize and controlled maize banded leaf sheath blight in the field, was effectively isolated and named strain SF05. High cellulase and chitinase activity of the strain were detected in this study, which might contribute to degrading the cell wall of fungi. Furthermore, different resistant genes such as , and were elicited differently by the strain in the leaves and stems of maize. In order to explain the biocontrol mechanism of strain SF05, the genome was sequenced and then the genes involving the biocontrol mechanism including biofilm formation pathways genes, cell wall degradation enzymes, secondary metabolite biosynthesis gene clusters and volatile organic compounds biosynthesis genes were predicted. The study revealed the biocontrol mechanism of strain SF05 preliminary and laid a foundation for further research of biocontrol mechanism of .
PubMed: 35889037
DOI: 10.3390/microorganisms10071318 -
Biotechnology Reports (Amsterdam,... Jun 2022We report the phenotypic variation in E681 (E681), a plant growth-promoting rhizobacterium (PGPR) isolated from a winter barley root in Korea. Phenotypic variation...
We report the phenotypic variation in E681 (E681), a plant growth-promoting rhizobacterium (PGPR) isolated from a winter barley root in Korea. Phenotypic variation (F-type) occurred when E681 (B-type) was grown in the media, and F-type was generated from B-type. B- and F-types were characterized by their morphological, Biolog, and GC-MIDI analyses. F-type cells altered the original biological capacity of B-type cells on endospore and flagella formation, changes in pH in culture, and carbon utilization. In growth curve analysis, B-type variants recovered bacterial growth as the variation occurred after the decline phase, but F-type variants did not. To determine this cause, we conducted comparative proteome analysis between B- and F-types using two-dimensional gel electrophoresis (2-DE). Of the identified proteins, 47% were involved in glycolysis and other metabolic pathways associated with carbohydrate metabolism. Therefore, our findings provide new knowledge on the mechanism of phenotypic variation and insights into agricultural biotechnology.
PubMed: 35686012
DOI: 10.1016/j.btre.2022.e00719 -
Frontiers in Bioengineering and... 2022Production of some antimicrobial peptides by bacterial producers is a resource-intensive process, thus, using inexpensive growth media and simplifying antimicrobial...
Production of some antimicrobial peptides by bacterial producers is a resource-intensive process, thus, using inexpensive growth media and simplifying antimicrobial extraction and down-stream processing are highly desirable. Acid whey, a dairy industry waste, is explored as a medium for production of broad-spectrum antimicrobials from selected bacteriocinogenic bacteria. Neutralized and yeast extract-supplemented acid whey was suitable for production of antimicrobials by four tested strains, but OSY-EC was the most prolific antimicrobial producer. Concentrating synthesized antimicrobials during culture incubation using beads of polymeric adsorbent resin, followed by solvent extraction and freeze-drying, resulted in antimicrobials-rich powder (AMRP). Under these conditions, OSY-EC produced paenibacillin, polymyxin E, and fusaricidin, which are active against Gram-positive and Gram-negative bacteria and fungi, respectively. When media containing 2x and 4x minimum inhibitory concentrations of AMRP were inoculated with and , microbial populations decreased by ≥4-log CFU ml in tryptic soy broth and ≥3.5-log CFU ml in milk. The antimicrobial mechanism of action of AMRP solutions was attributed to the disruption of cytoplasmic membrane of indicator strains, and . These findings exemplify promising strategies for valorization of acid whey microbial bioreactions to yield potent antimicrobials.
PubMed: 35646844
DOI: 10.3389/fbioe.2022.869778