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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 -
Access Microbiology 2023Xylanase breaks xylan down to xylose, which is used in industries such as pulp and paper, food and feed, among others. The utilization of wastes for xylanase production...
Xylanase breaks xylan down to xylose, which is used in industries such as pulp and paper, food and feed, among others. The utilization of wastes for xylanase production is economical, hence this work aimed at producing xylanase through solid-state fermentation and characterizing the enzyme. Xylanase-producing strains of and GIO were inoculated separately in a 5 and 10 day solid fermentation study on maize straw, rice straw, sawdust, corn cob, sugarcane bagasse, conifer litters, alkaline-pretreated maize straw (APM) and combined alkaline and biological-pretreated maize straw, respectively. The best substrate was selected for xylanase production. The crude enzyme was extracted from the fermentation medium and xylanase activity was characterized using parameters such as temperature, cations, pH and surfactants. Among different substrates, the highest xylanase activity of 3.18 U ml was recorded when GIO was grown on APM. The xylanase produced by GIO and had the highest activities (3.67 U ml and 3.36 U ml) at 40 °C after 30 and 45 min of incubation, respectively. Optimal xylanase activities (4.58 and 3.58 U ml) of GIO and , respectively, were observed at pH 5.0 and 6.2. All cations used enhanced xylanase activities except magnesium ion. Sodium dodecyl sulfate supported the highest xylanase activity of 6.13 and 6.90 U ml for GIO and , respectively. High yields of xylanase were obtained from GIO and cultivated on APM. The xylanase activities were affected by pH, temperature, surfactants and cations.
PubMed: 37424564
DOI: 10.1099/acmi.0.000506.v5 -
Microbial Cell Factories Jan 2024Silk proteins have emerged as versatile biomaterials with unique chemical and physical properties, making them appealing for various applications. Among them, spider...
BACKGROUND
Silk proteins have emerged as versatile biomaterials with unique chemical and physical properties, making them appealing for various applications. Among them, spider silk, known for its exceptional mechanical strength, has attracted considerable attention. Recombinant production of spider silk represents the most promising route towards its scaled production; however, challenges persist within the upstream optimization of host organisms, including toxicity and low yields. The high cost of downstream cell lysis and protein purification is an additional barrier preventing the widespread production and use of spider silk proteins. Gram-positive bacteria represent an attractive, but underexplored, microbial chassis that may enable a reduction in the cost and difficulty of recombinant silk production through attributes that include, superior secretory capabilities, frequent GRAS status, and previously established use in industry.
RESULTS
In this study, we explore the potential of gram-positive hosts by engineering the first production and secretion of recombinant spider silk in the Bacillus genus. Using an industrially relevant B. megaterium host, it was found that the Sec secretion pathway enables secretory production of silk, however, the choice of signal sequence plays a vital role in successful secretion. Attempts at increasing secreted titers revealed that multiple translation initiation sites in tandem do not significantly impact silk production levels, contrary to previous findings for other gram-positive hosts and recombinant proteins. Notwithstanding, targeted amino acid supplementation in minimal media was found to increase production by 135% relative to both rich media and unaltered minimal media, yielding secretory titers of approximately 100 mg/L in flask cultures.
CONCLUSION
It is hypothesized that the supplementation strategy addressed metabolic bottlenecks, specifically depletion of ATP and NADPH within the central metabolism, that were previously observed for an E. coli host producing the same recombinant silk construct. Furthermore, this study supports the hypothesis that secretion mitigates the toxicity of the produced silk protein on the host organism and enhances host performance in glucose-based minimal media. While promising, future research is warranted to understand metabolic changes more precisely in the Bacillus host system in response to silk production, optimize signal sequences and promoter strengths, investigate the mechanisms behind the effect of tandem translation initiation sites, and evaluate the performance of this system within a bioreactor.
Topics: Silk; Bacillus megaterium; Escherichia coli; Recombinant Proteins; Bioreactors
PubMed: 38279170
DOI: 10.1186/s12934-024-02304-5 -
Polymers Nov 2023This study aimed to analyze the production of poly(3-hydroxybutyrate) (PHB) from lignocellulosic biomass through a series of steps, including microwave irradiation,...
This study aimed to analyze the production of poly(3-hydroxybutyrate) (PHB) from lignocellulosic biomass through a series of steps, including microwave irradiation, ammonia delignification, enzymatic hydrolysis, and fermentation, using the ATCC 14581 strain. The lignocellulosic biomass was first pretreated using microwave irradiation at different temperatures (180, 200, and 220 °C) for 10, 20, and 30 min. The optimal pretreatment conditions were determined using the central composite design (CCD) and the response surface methodology (RSM). In the second step, the pretreated biomass was subjected to ammonia delignification, followed by enzymatic hydrolysis. The yield obtained for the pretreated and enzymatically hydrolyzed biomass was lower (70.2%) compared to the pretreated, delignified, and enzymatically hydrolyzed biomass (91.4%). These hydrolysates were used as carbon substrates for the synthesis of PHB using ATCC 14581 in batch cultures. Various analytical methods were employed, namely nuclear magnetic resonance (H-NMR andC-NMR), electrospray ionization mass spectrometry (EI-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA), to identify and characterize the extracted PHB. The XRD analysis confirmed the partially crystalline nature of PHB.
PubMed: 38231921
DOI: 10.3390/polym15234488 -
3 Biotech Aug 2023Plant growth-promoting rhizobacteria (PGPRs) are bacteria that colonize the plant roots. These beneficial bacteria have an influence on plant development through...
UNLABELLED
Plant growth-promoting rhizobacteria (PGPRs) are bacteria that colonize the plant roots. These beneficial bacteria have an influence on plant development through multiple mechanisms, such as nutrient availability, alleviating biotic and abiotic stress, and secrete phytohormones. Therefore, their inoculation constitutes a powerful tool towards sustainable agriculture and crop production. To understand plant-PGPRs interaction we present the classification of PGPR using machine learning and meta-learning classifiers namely Support Vector Machine (SVM), Kernel Logistic Regression (KLR), meta-SVM and meta-KLR to predict the presence of inoculated in tomato root tissues using publicly available transcriptomic data. The original dataset presents 36 significantly differentially expressed genes. As the meta-KLR achieved near-optimal performance considering all the relevant metrics, this meta learner was afterwards used to identify the informative genes (IGs). The outcomes showed 157 IGs, being present all significantly differentially expressed genes previously identified. Among the IGs, 113 were identified as tomato genes, 5 as proteins, 1 as protein and 6 were unidentified. Then, a functional enrichment analysis of the tomato IGs showed 175 biological processes, 22 molecular functions and 20 KEGG pathways involved in tomato interaction. Furthermore, the biological networks study of their orthologous genes identified the co-expression, predicted interaction, shared protein domains and co-localization networks.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13205-023-03690-0.
PubMed: 37449251
DOI: 10.1007/s13205-023-03690-0 -
Molecules (Basel, Switzerland) Jul 2023Wild-type cytochrome P450 CYP102A1 from is a highly efficient monooxygenase for the oxidation of long-chain fatty acids. The unique features of CYP102A1, such as high... (Review)
Review
Wild-type cytochrome P450 CYP102A1 from is a highly efficient monooxygenase for the oxidation of long-chain fatty acids. The unique features of CYP102A1, such as high catalytic activity, expression yield, regio- and stereoselectivity, and self-sufficiency in electron transfer as a fusion protein, afford the requirements for an ideal biocatalyst. In the past three decades, remarkable progress has been made in engineering CYP102A1 for applications in drug discovery, biosynthesis, and biotechnology. The repertoire of engineered CYP102A1 variants has grown tremendously, whereas the substrate repertoire is avalanched to encompass alkanes, alkenes, aromatics, organic solvents, pharmaceuticals, drugs, and many more. In this article, we highlight the major advances in the past five years in our understanding of the structure and function of CYP102A1 and the methodologies used to engineer CYP102A1 for novel applications. The objective is to provide a succinct review of the latest developments with reference to the body of CYP102A1-related literature.
Topics: NADPH-Ferrihemoprotein Reductase; Cytochrome P-450 Enzyme System; Oxidation-Reduction; Electron Transport; Bacterial Proteins; Bacillus megaterium
PubMed: 37513226
DOI: 10.3390/molecules28145353 -
Iranian Journal of Microbiology Oct 2023Plant growth-promoting bacteria (PGPB) may reduce the negative effects of salinity stress. The aim of this study was to optimize RTS1 and characterize the effect of the...
BACKGROUND AND OBJECTIVES
Plant growth-promoting bacteria (PGPB) may reduce the negative effects of salinity stress. The aim of this study was to optimize RTS1 and characterize the effect of the PGPB on the physiological characteristics of tomato ().
MATERIALS AND METHODS
The Central composite design (CCD) of response surface methodology (RSM) was used to optimize RTS1 to produce maximum cell biomass and spores. Then the effect of the PGPB on the physiological characteristics of tomato (), including membrane stability, leaf relative water content percentage, anthocyanin and carotenoids content, chlorophyll photosynthetic parameters, sugar and starch level, superoxide anion and antioxidant activity under salt stress conditions. The NFB medium was inoculated with 5% bacterial culture and the fermentation was carried out in a 10-lit fermenter.
RESULTS
After optimization, the amount of cell biomass by the model was 9.45 log10 CFUs/mL, which showed a 1.2-fold increase compared to the non-optimized medium. Usage of bacteria under the optimal conditions of the culture medium may increase the stability of the membrane and improve the relative water content. Bacteria were able to prevent the excessive increase of anthocyanins. Oxidative stress led to an increase in the content of chlorophyll a, while causing the degradation of chlorophyll b. Bacterial inoculation led to an increase in the level of sugar and starch compared to the control. PGPB showed an increasing effect on the amount of superoxide anion production and caused a significant increase in the antioxidant activity under salinity stress conditions.
CONCLUSION
The PGPB can be a promising way to boost physiological characteristics of tomato plant under salinity stress. Also, sporulation capacity of with high bacterial cell density in fermenter produce a sustainable product for tomato plants.
PubMed: 37941883
DOI: 10.18502/ijm.v15i5.13874 -
Veterinary World Dec 2023The rapid development of aquaculture as a major food sector is accompanied by challenges, including diseases that affect tilapia farming worldwide. One such infectious...
BACKGROUND AND AIM
The rapid development of aquaculture as a major food sector is accompanied by challenges, including diseases that affect tilapia farming worldwide. One such infectious disease caused by poses a serious threat to tilapia populations. Probiotics have emerged as a potentially safe preventive measure against infection. However, antimicrobial resistance from antibiotic-resistant bacteria remains a concern because it can lead to the spread of resistant bacteria and serve as a reservoir of antibiotic-resistant genes in fishes and the surrounding environment. This study aimed to identify candidate probiotic bacteria capable of promoting tilapia growth, providing resistance to infection, devoid of potential pathogenicity, and free from antibiotic resistance genes. Subsequently, the performance of these probiotic candidates in tilapia was evaluated.
MATERIALS AND METHODS
spp., and were examined to assess their antibacterial properties, hemolytic patterns, and antibiotic resistance genes. We used the specific primers , , , , , , , and that were used for antibiotic resistance gene detection. probiotic efficacy was evaluated by administering probiotic candidates in tilapia feed at a concentration of 1 × 10 colonies/mL/50 g of feed over a 60-day maintenance period. Resistance to infection was observed for 14 days after the challenge test.
RESULTS
, , and spp. were identified as promising probiotic candidates among the bacterial isolates. On the other hand, , , and carried resistance genes and exhibited a β hemolytic pattern, rendering them unsuitable as probiotic candidates. The selected probiotic candidates (, , and spp.) demonstrated the potential to enhance tilapia growth, exhibited no pathogenic tendencies, and were free from antibiotic resistance genes. Supplementation with and spp. enhanced tilapia resistance to infection, whereas supplementation showed an insignificant survival rate compared with controls after the challenge test period.
CONCLUSION
Probiotics, particularly , and spp., enhance growth and resistance against infection, without harboring antibiotic resistance genes. Selecting probiotic candidates based on antibiotic resistance genes is essential to ensure the safety of fish, the environment, and human health.
PubMed: 38328352
DOI: 10.14202/vetworld.2023.2504-2514 -
ACS Sensors Jul 2023Antimicrobial peptides (AMPs) represent a promising class of compounds to fight antibiotic-resistant infections. In most cases, they kill bacteria by making their...
Antimicrobial peptides (AMPs) represent a promising class of compounds to fight antibiotic-resistant infections. In most cases, they kill bacteria by making their membrane permeable and therefore exhibit low propensity to induce bacterial resistance. In addition, they are often selective, killing bacteria at concentrations lower than those at which they are toxic to the host. However, clinical applications of AMPs are hindered by a limited understanding of their interactions with bacteria and human cells. Standard susceptibility testing methods are based on the analysis of the growth of a bacterial population and therefore require several hours. Moreover, different assays are required to assess the toxicity to host cells. In this work, we propose the use of microfluidic impedance cytometry to explore the action of AMPs on both bacteria and host cells in a rapid manner and with single-cell resolution. Impedance measurements are particularly well-suited to detect the effects of AMPs on bacteria, due to the fact that the mechanism of action involves perturbation of the permeability of cell membranes. We show that the electrical signatures of cells and human red blood cells (RBCs) reflect the action of a representative antimicrobial peptide, DNS-PMAP23. In particular, the impedance phase at high frequency (e.g., 11 or 20 MHz) is a reliable label-free metric for monitoring DNS-PMAP23 bactericidal activity and toxicity to RBCs. The impedance-based characterization is validated by comparison with standard antibacterial activity assays and absorbance-based hemolytic activity assays. Furthermore, we demonstrate the applicability of the technique to a mixed sample of cells and RBCs, which paves the way to study AMP selectivity for bacterial versus eukaryotic cells in the presence of both cell types.
Topics: Humans; Antimicrobial Peptides; Antimicrobial Cationic Peptides; Electric Impedance; Bacteria; Erythrocytes
PubMed: 37421371
DOI: 10.1021/acssensors.3c00256 -
Heliyon Aug 2023L. is a large, spreading type of tree which usually grows in tropical environment, especially at coastal area with sandy stones. The current study evaluated anti-...
L. is a large, spreading type of tree which usually grows in tropical environment, especially at coastal area with sandy stones. The current study evaluated anti- potential of the ethanolic ( L.) leaf extract (EKLE) as antibacterial and sporicidal agent against vegetative cells and spores of spp. The antibacterial activity of EKLE against spp. (. ATCC33019, . ATCC14884, . ATCC6633 and . ATCC14581) vegetative cells were determined by performing well diffusion assay (WDA), minimum inhibition concentration (MIC), minimum bacterial concentration (MBC) and time-kill curve analyses. The sporicidal activity was tested at different concentrations of EKLE. Then, the extract's stability in terms of antibacterial and sporicidal activities upon exposure to different temperatures and pHs were carried out. Results demonstrated inhibition zones of EKLE against spp. was in the range of 9.25 ± 0.75 mm - 11.67 ± 0.47 mm. All vegetative cells of spp. were inhibited with MIC values at 0.63-1.25 mg/mL and can be completely killed with MBC values of 0.63 - >5.00 mg/mL. Time-kill analysis showed all the spp. tested can be completely killed at concentrations of 2.50-5.00 mg/mL from 1 to 4 h. EKLE concentration of 1% (w/v) completely killed all spp. spores at different exposure time. The antibacterial and sporicidal activities of EKLE were not affected by exposure to different temperatures (4, 30, 50, 80 and 121 °C) and pHs (3, 7 and 10), revealing the stability of the extract against different conditions. In conclusion, L. leaf exhibits antibacterial and sporicidal activities against spp., therefore, the extract can be developed as anti- agent, paving the way for its utilization in food industry as a natural food preservative.
PubMed: 37600365
DOI: 10.1016/j.heliyon.2023.e18749