Degradation Of Metabolites Research Articles

Protein kinase N1 deficiency results in upregulation of cerebral energy metabolism and is highly protective in in vivo and in vitro stroke models

Background and aimWe recently identified protein kinase N1 (PKN1) as a master regulator of brain development. However, its function in the adult brain has not been clearly established. In this study, we assessed the cerebral energetic phenotype of wildtype (WT) and global Pkn1 knockout (Pkn1−/−) animals under physiological and pathophysiological conditions. MethodsCerebral energy metabolism was analyzed by 13C6-glucose tracing in vivo and real time seahorse analysis of extracellular acidification rates as well as mitochondrial oxygen consumption rates (OCR) of brain slice punches in vitro. Isolated WT and Pkn1−/− brain mitochondria were tested for differences in OCR with different substrates. Metabolite levels were determined by mass spectrometric analysis in brain slices under control and energetic stress conditions, induced by oxygen-glucose deprivation and reperfusion, an in vitro model of ischemic stroke. Differences in enzyme activities were assessed by enzymatic assays, western blotting and bulk RNA sequencing. A middle cerebral artery occlusion stroke model was used to analyze lesion volumes and functional recovery in WT and Pkn1−/− mice. ResultsPkn1 deficiency resulted in a remarkable upregulation of cerebral energy metabolism, in vivo and in vitro. This was due to two separate mechanisms involving an enhanced glycolytic flux and higher pyruvate-induced mitochondrial OCR. Mechanistically we show that Pkn1−/− brain tissue exhibits an increased activity of the glycolysis rate-limiting enzyme phosphofructokinase. Additionally, glucose-1,6-bisphosphate levels, a metabolite that increases mitochondrial pyruvate uptake, were elevated upon Pkn1 deficiency. Consequently, Pkn1−/− brain slices had more ATP and a greater accumulation of ATP degradation metabolites during energetic stress. This translated into increased phosphorylation and activity of adenosine monophosphate (AMP)-activated protein kinase (AMPK) during in vitro stroke. Accordingly, Pkn1−/− brain slices showed a post-ischemic transcriptional upregulation of energy metabolism pathways and Pkn1 deficiency was strongly protective in in vitro and in vivo stroke models. While inhibition of mitochondrial pyruvate uptake only moderately affected the protective phenotype, inhibition of AMPK in Pkn1−/− slices increased post-ischemic cell death in vitro. ConclusionThis is the first study to comprehensively demonstrate an essential and unique role of PKN1 in cerebral energy metabolism, regulating glycolysis and mitochondrial pyruvate-induced respiration. We further uncovered a highly protective phenotype of Pkn1 deficiency in both, in vitro and in vivo stroke models, validating inhibition of PKN1 as a promising new therapeutic target for the development of novel stroke therapies.

Enhanced biodegradation of trinitrotoluene in rhizosphere soil by native grasses

Soil contamination by the munition explosive residues of 2,4,6-trinitrotoluene (TNT) and its metabolites resulting primarily from military operations has been identified as a threat to human health and ecosystems. Biodegradation by native plants to remove this hazardous compound or reduce its toxicity is considered a cost-effective and environmentally sound approach for the cleanup or restoration of TNT-contaminated soils. This study aims to investigate the TNT biodegradation and kinetics by two selected native grasses in the species-specific rhizosphere soils through growth chamber experiments. Native eastern gamma grass (Tripsacum dactyloides) and switchgrass (Panicum virgatum L.) were grown in soil spiked with 14C-TNT for 8 weeks. The 14C-TNT degradation and degradative metabolite profile in the rhizosphere soils were determined by liquid scintillation counter and high-performance liquid chromatography, respectively. The results indicated that both native grass species significantly enhanced the TNT degradation in the rhizosphere soils as compared with the control rhizosphere soils. More than 95% of the applied 14C-TNT was degraded in the first 7 days, and the rate then reached a steady state afterward, but less than 10% of the TNT applied was completely mineralized and transformed into CO2. The degradative reaction was found to follow second-order kinetics. Six major TNT degradative metabolites have been detected and identified in the rhizosphere soils. Overall, switchgrass appeared more effective for biodegrading TNT than eastern gamma grass. This research demonstrated that the native grass species, especially switchgrass, has the potential to mitigate the adverse human health and ecological risks of TNT-contaminated sites and can be considered an environmentally friendly, sustainable approach to safeguarding human health from TNT contamination.

Simultaneous and selective determination of purine metabolites in human urine samples using nanocomposite modified glassy carbon electrode

Herein, we reported the acid functionalized multiwalled carbon nanotubes (FMWCNTs) entrapped with polymer films derived from 3-amino-5-mercapto-1,2,4-triazole (AMTa) substrate sensitive and selective determination of purine metabolites in human urine samples. The FMWCNTs are covalently assembled on the GCE by simple carbodiimide coupling with diamine self-assemble monolayer (SAM) modified GCE. The nanocomposite on electrode surface is developed by electrochemical polymerization of AMTa over the FMWCNTs modified GCE (FMWCNTs/p-AMTa). The SEM images clearly shows the uniform deposition of p-AMTa on the surface walls of FMWCNTs, especially the diameter of the FMWCNTs is notably increased from 38 to 45 nm after the deposition of p-AMTa film on FMWCNTs. The nanocomposite was then exploited for the simultaneous and selective detection of purine metabolites. The alteration in the concentration of any one of purine metabolites can also change the concentration of next degradation metabolite, which leads to several critical diseases in our body. Thus, the simultaneous and sensitive determination of purine metabolites (uric acid, xanthine, hypoxanthine and inosine) using FMWCNTs/p-AMTa nanocomposite electrode is of high importance in clinical and healthcare aspects. In particular, the nanocomposite electrode shows higher electrocatalytic activity and a low limit of detection (LOD) toward these purine metabolites over the reported procedures. The practicability of the present approach is verified with urine samples and displays good recovery results.

Rifampicin and its derivatives: stability, disposition, and affinity towards pregnane X receptor employing 2D and 3D primary human hepatocytes

Rifampicin is a model ligand of the pregnane X receptor (PXR), the nuclear receptor involved in the regulation of cytochrome P450 3A4 (CYP3A4). Rifampicin forms several degradation products and metabolites of which 25-desacetylrifampicin is the most abundant in vivo. Here, we aimed to study both the stability and metabolism of rifampicin in media and 2D and 3D primary human hepatocytes (PHHs). Additionally, we analyzed interactions of rifampicin derivatives with PXR. We described that rifampicin gradually degrades by more than 50 % in the medium partly into quinone over 72 h. We observed 25-desacetylrifampicin in 2D PHHs but not in 3D PHHs. Contrary, rifampicin was converted into quinone in a one-direction process in media of 3D PHHs. The potency of rifampicin and its derivatives to activate human PXR was arranged as follows: 3-formylrifamycin SV > rifampicin quinone > rifampicin > rifampicin N-oxide > 25-desacetylrifampicin, respectively, but none activates mouse and rat PXR. The binding differences between rifampicin and 25-desacetylrifampicin were modeled in silico. Finally, we showed that overexpressed uptake organic anion transporting polypeptide 1B1 (OATP1B1) potentiated activation of PXR by rifampicin and rifampicin quinone, but overexpressed efflux multidrug resistance protein 1 (MDR1) decreased PXR activation by all derivatives.

Pyrene biodegradation by bacterial consortia enriched from coastal and marine sediments: Insights into bacterial community structures and functions

As a representative polycyclic aromatic hydrocarbon (PAH), pyrene poses a significant threat to the environment and public health due to its persistence and potential toxicity. Extensive research has been conducted on biodegradation of pyrene, highlighting the crucial need to unravel its degradation mechanisms. Coastal and marine sediments are promising sources for discovering microbial candidates capable of degrading pyrene. In this study, three bacterial consortia, designated as BS, YS, and SS, were enriched from sediments collected from the Bohai Sea, Yellow Sea, and Liao River estuarine wetland, respectively. The bacterial consortia BS, YS, and SS demonstrated high pyrene degradation efficiencies, achieving 86.61 %, 80.39 %, and 75.70 % degradation at the concentration of 50 mg/L within 8 days, respectively. High-throughput sequencing of 16S rRNA gene amplicons revealed Pandoraea, Delftia, and Pseudomonas as the dominant populations in bacterial consortia BS, YS, and SS, respectively, with some species potentially being novel pyrene degraders. Further analysis included identifying pyrene degradation metabolites by LC-Q-TOF-MS (high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry) and predicting functional genes through PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved Stats). Based on these results, the metabolic pathways for pyrene degradation by the bacterial consortia were proposed, which predominantly involved the dioxygenation pathway. Overall, these findings should offer valuable bacterial resources for facilitating the bioremediation of PAH-contaminated environments.

Enhanced biodegradation of polychlorinated biphenyls by co-cultivation of resuscitated strains with unique advantages

The investigation into viable but non-culturable (VBNC) bacteria through the implementation of resuscitation promoting factors (Rpfs) has broadened the potential sources for isolating strains capable of degrading polychlorinated biphenyls (PCBs). Nonetheless, there has been limited research on the efficacy of resuscitated strains and the potential improvement of their performance through co-cultivation. In this work, the PCB degradation potential of resuscitated strains, specifically Pseudomonas sp. HR1 and Achromobacter sp. HR2, as well as their co-cultures, was investigated. Of particular importance was the comparative analysis between the optimal co-culture and individual strains regarding their ability to degrade PCB homologs and mineralize intermediate metabolites. The results suggested that the resuscitated strains HR1 and HR2 demonstrated robust growth and effective degradation of Aroclor 1242. The co-culture CO13, with an optimal HR1 to HR2 ratio of 1:3, exhibited a remarkable improvement in PCB degradation and intermediate metabolite mineralization compared to individual strains. Analysis of functional genes and degradation metabolites revealed that both the individual strains and co-culture CO13 degraded PCBs via the HOPDA-benzoate pathway, then mineralized through protocatechuate meta- and ortho-cleavage pathways, as well as the catechol ortho-cleavage pathway. This study represents the first documentation of the improved PCB degradation through the co-cultivation of resuscitated strains, which highlights the great promise of these resuscitated strains and their co-cultures as effective bio-inoculants for enhanced bioremediation.

Kraft Lignin Decomposition by Forest Soil Bacterium Pseudomonas kribbensis CHA-19.

Identification of the biochemical metabolic pathway for lignin decomposition and the responsible degradative enzymes is needed for the effective biotechnological valorization of lignin to renewable chemical products. In this study, we investigated the decomposition of kraft lignin by the soil bacterium Pseudomonas kribbensis CHA-19, a strain that can utilize kraft lignin and its main degradation metabolite, vanillic acid, as growth substrates. Gel permeation chromatography revealed that CHA-19 decomposed polymeric lignin and degraded dehydrodivanillin (a representative lignin model compound); however, the degradative enzyme(s) and mechanism were not identified. Quantitative polymerase chain reaction with mRNAs from CHA-19 cells induced in the presence of lignin showed that the putative genes coding for two laccase-like multicopper oxidases (LMCOs) and three dye-decolorizing peroxidases (DyPs) were upregulated by 2.0- to 7.9-fold compared with glucose-induced cells, which indicates possible cooperation with multiple enzymes for lignin decomposition. Computational homology analysis of the protein sequences of LMCOs and DyPs also predicted their roles in lignin decomposition. Based on the above data, CHA-19 appears to initiate oxidative lignin decomposition using multifunctional LMCOs and DyPs, producing smaller metabolites such as vanillic acid, which is further degraded via ortho- and meta-ring cleavage pathways. This study not only helps to better understand the role of bacteria in lignin decomposition and thus in terrestrial ecosystems, but also expands the biocatalytic toolbox with new bacterial cells and their degradative enzymes for lignin valorization.

Heavily polluted mechanic workshop soil and its phenanthrene-degrading Bacillus thuringiensis

Mechanic workshops in residential areas are sites referenced for small-scale chronic contamination with petroleum hydrocarbons (HC) and associated pollutants like heavy metals. The main aim of this study was to isolate from a mechanic workshop soil in Lagos a novel indigenous bacterium with potential for degradation of phenanthrene, a model polyaromatic compound. Gas chromatographic analysis revealed concentrations of HC (20,055 mg kg-1), lead (156.19 mg kg-1) and zinc (202.005 mg kg-1) in excess of regulatory limits in the soil. Continuous enrichment resulted in the isolation of a bacterium strain ALSL2, which was identified by 16S rRNA gene sequencing as Bacillus thuringiensis. Strain ALSL2 showed broad specificity for a range of HCs including phenanthrene, anthracene, biphenyl, dibenzothiophene, crude oil, diesel and kerosene and also showed biosurfactant production with emulsification index 55.2 %, 65.7 % and 58.7 % on crude oil, kerosene and vegetable oil respectively. The isolate showed evidence of dioxygenase activity and utilized metabolites of aromatic hydrocarbon degradation including 1-naphthol and O-phthalate. At the end of 10 days 51.45 % of phenanthrene was degraded at the rate of 7.922 mg l−1 d−1, degradation constant 0.073 d−1, and half-life 9.864 d. The corresponding values for anthracene were 69.11 %, 9.92 mg l−1 d−1., 0.11 d−1, and 5.924 d respectively. Our findings represent a remarkable addition to available indigenous bioresources with potential for application in bioremediation, and further highlight mechanic workshop soils as veritable source of such isolate.

Exploring the potential of horse amendment for the remediation of HCHs-polluted soils

This study assessed for the first time the bioremediation potential of an organic horse amendment in soils contaminated with solid wastes of the obsolete pesticide lindane (α−hexachlorocyclohexane (α−HCH) = 80 mg kg−1, β−HCH = 40 mg kg−1, γ,δ,ε−HCH≈10 mg kg−1) searching for a self-sufficient bio-based economy. Four treatments were implemented: polluted (PS, ΣHCHs = 130 mg kg−1) and control (CS, ΣHCHs = 1.24 mg kg−1) soils and the respective amended soils (APS and ACS). A commercial amendment, coming from organic wastes, was used for soil biostimulation (5% dry weight), and the temporal evolution of the enzymatic activity (dehydrogenase, β-glucosidase activity, phenoloxidase, arylamidase, phosphatase, and urease) and HCHs concentration of the soils was evaluated over 55 days under controlled humidity and temperature conditions. The horse amendment positively influenced the physicochemical properties of the soil by reducing pH (from 8.3 to 8) and increasing the organic matter (TOC from 0.5 to 3.3%) and nutrient content (P and NH4+ from 24.1 to 13.7 to 142.1 and 41.2 mg kg−1, respectively). Consequently, there was a notable enhancement in the soil biological activity, specifically in the enzymatic activity of dehydrogenase, phenol-oxidase, phosphatase, and urease and, therefore, in HCH degradation, which increased from <1 to 75% after the incubation period. According to the chlorine position on the cyclohexane ring, the following ranking has been found for HCHs degradation: β-HCH (46%) < ε-HCH (57%) < α-HCH (91%) ≈ δ-HCH (91%) < γ-HCH (100%). Pentachlorocyclohexene (PCCH) and 1,2,4-trichlorobenzene (1,2,4-TCB) were identified as HCHs degradation metabolites and disappeared at the end of the incubation time. Although further research is required, these preliminary findings suggest that organic amendments represent a sustainable, harmless, and cost-effective biostimulation approach for remediating soils contaminated with recalcitrant HCHs, boosting the circular economy.

Untargeted metabolomics reveal signatures of a healthy lifestyle

This cross-sectional study investigated differences in the plasma metabolome in two groups of adults that were of similar age but varied markedly in body composition and dietary and physical activity patterns. Study participants included 52 adults in the lifestyle group (LIFE) (28 males, 24 females) and 52 in the control group (CON) (27 males, 25 females). The results using an extensive untargeted ultra high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) metabolomics analysis with 10,535 metabolite peaks identified 486 important metabolites (variable influence on projections scores of VIP ≥ 1) and 16 significantly enriched metabolic pathways that differentiated LIFE and CON groups. A novel metabolite signature of positive lifestyle habits emerged from this analysis highlighted by lower plasma levels of numerous bile acids, an amino acid profile characterized by higher histidine and lower glutamic acid, glutamine, β-alanine, phenylalanine, tyrosine, and proline, an elevated vitamin D status, higher levels of beneficial fatty acids and gut microbiome catabolism metabolites from plant substrates, and reduced levels of N-glycan degradation metabolites and environmental contaminants. This study established that the plasma metabolome is strongly associated with body composition and lifestyle habits. The robust lifestyle metabolite signature identified in this study is consistent with an improved life expectancy and a reduced risk for chronic disease.

Detoxification of phoxim by a gut bacterium of Delia antiqua

The presence of certain associated bacteria has been reported to increase pest resistance to pesticides, which poses a serious threat to food security and the environment. Researches on the above microbe-derived pesticide resistance would bring innovative approaches for pest management. Investigations into the phoxim resistance of Delia antiqua, one Liliaceae crop pests, revealed the contribution of a phoxim-degrading gut bacterium, D39, to this resistance. However, how the strain degraded phoxim was unknown. In this study, the role of D39 in phoxim degradation and resistance was first confirmed. DT, which had an identical taxonomy but lacked phoxim-degrading activity, was analyzed alongside D39 via comparative genomics to identify the potential phoxim degrading genes. In addition, degradation metabolites were identified, and a potential degradation pathway was proposed. Furthermore, the main gene responsible for degradation and the metabolites of phoxim were further validated via prokaryotic expression. The results showed that D39 contributed to resistance in D. antiqua larva by degrading phoxim. Phoxim was degraded by an enzyme encoded by the novel gene phoD in D39 to O,O-diethyl hydrogen phosphorothioate and 2-hydroxyimino-2-phenylacetonitrile. Finally, downstream products were metabolized in the tricarboxylic acid cycle. Further analysis via prokaryotic expression of phoD confirmed its degradation activity. The mechanisms through which gut microbes promote pesticide resistance are elucidated in this study. These results could aid in the development of innovative pest control methods. In addition, this information could also be used to identify microbial agents that could be applied for the remediation of pesticide contamination.

Glyphosate resistance and biodegradation by Burkholderia cenocepacia CEIB S5-2.

Glyphosate is a broad spectrum and non-selective herbicide employed to control different weeds in agricultural and urban zones and to facilitate the harvest of various crops. Currently, glyphosate-based formulations are the most employed herbicides in agriculture worldwide. Extensive use of glyphosate has been related to environmental pollution events and adverse effects on non-target organisms, including humans. Reducing the presence of glyphosate in the environment and its potential adverse effects requires the development of remediation and treatment alternatives. Bioremediation with microorganisms has been proposed as a feasible alternative for treating glyphosate pollution. The present study reports the glyphosate resistance profile and degradation capacity of the bacterial strain Burkholderia cenocepacia CEIB S5-2, isolated from an agricultural field in Morelos-México. According to the agar plates and the liquid media inhibition assays, the bacterial strain can resist glyphosate exposure at high concentrations, 2000mg·L-1. In the degradation assays, the bacterial strain was capable of fast degrading glyphosate (50mg·L-1) and the primary degradation metabolite aminomethylphosphonic acid (AMPA) in just eight hours. The analysis of the genomic data of B. cenocepacia CEIB S5-2 revealed the presence of genes that encode enzymes implicated in glyphosate biodegradation through the two metabolic pathways reported, sarcosine and AMPA. This investigation provides novel information about the potential of species of the genus Burkholderia in the degradation of the herbicide glyphosate and its main degradation metabolite (AMPA). Furthermore, the analysis of genomic information allowed us to propose for the first time a metabolic route related to the degradation of glyphosate in this bacterial group. According to the findings of this study, B. cenocepacia CEIB S5-2 displays a great glyphosate biodegradation capability and has the potential to be implemented in glyphosate bioremediation approaches.

Endogenous ureides are employed as a carbon source in Arabidopsis plants exposed to carbon starvation conditions

Ureides, the degraded products of purine catabolism in Arabidopsis, have been shown to act as antioxidant and nitrogen sources. Herein we elucidate purine degraded metabolites as a carbon source using the Arabidopsis Atxdh1, Ataln, and Ataah knockout (KO) mutants vis-à-vis wild-type (WT) plants. Plants were grown under short-day conditions on agar plates containing half-strength MS medium with or without 1% sucrose. Notably, the absence of sucrose led to diminished biomass accumulation in both shoot and root tissues of the Atxdh1, Ataln, and Ataah mutants, while no such effect was observed in WT plants. Moreover, the application of sucrose resulted in a reduction of purine degradation metabolite levels, specifically xanthine and allantoin, predominantly within the roots of WT plants. Remarkably, an increase in proteins associated with the purine degradation pathway was observed in WT plants in the presence of sucrose. Lower glyoxylate levels in the roots but not in the shoot of the Atxdh1 mutant in comparison to WT, were observed under sucrose limitation, and improved by sucrose application in root, indicating that purine degradation provided glyoxylate in the root. Furthermore, the deficit of purine-degraded metabolites in the roots of mutants subjected to carbon starvation was partially mitigated through allantoin application. Collectively, these findings signify that under conditions of sucrose limitation and short-day growth, purines are primarily remobilized within the root system to augment the availability of ureides, serving as an additional carbon (as well as nitrogen) source to support plant growth.

Identification, degradation characteristics, and application of a newly isolated pyridine-degrading Paracidovorax sp. BN6-4.

The Paracidovorax sp. BN6-4 capable of degrading high concentrations of pyridine was isolated from the coking sludge. The removal rate of BN6-4 to 1,000 mg/L pyridine during 48 h was 97.49 ±1.59%. The primary intermediate metabolites of pyridine degradation by strain BN6-4 were identified by gas chromatography-mass spectrometry (GC-MS), including N-Ethylurea, acetamidoacetaldehyde, and N-Hydroxymethylacetamide, etc. Subsequently, two different biodegradation pathways of pyridine were proposed. First, the hydroxylation of pyridine to form the intermediates pyridin-2(1H)-one and 5,6-dihydropyridine-2,5-diol, the former undergoing oxidative ring opening and the latter oxidative ring opening via N-C2 and C2-C3 ring opening to ammonia and carbon dioxide. Furthermore, the organic matter was greatly degraded by the bioremediation of real coking wastewater using BN6-4. This study enriched the microbial resource for pyridine degradation and provided new insights about the biodegradation pathway of pyridine, which is of great significance for the pyridine pollution control and coking wastewater treatment.

Organophosphate ester additives and microplastics in benthic compartments from the Loire estuary (French Atlantic coast)

We report the first empirical confirmation of the co-occurrence of organophosphate esters (OPEs) additives and microplastics (MPs) in benthic compartments from the Loire estuary. Higher median concentrations of MPs (3387 items/kg dw), ∑13tri-OPEs (12.0 ng/g dw) and ∑4di-OPEs (0.7 ng/g dw) were measured in intertidal sediments with predominance of fine particles, and under higher anthropogenic pressures, with a general lack of seasonality. Contrarily, Scrobicularia plana showed up to 4-fold higher ∑tri-OPE concentrations in summer (reaching 37.0 ng/g dw), and similar spatial distribution. Polyethylene predominated in both compartments. Tris(2-ethylhexyl) phosphate (TEHP), its degradation metabolite (BEHP) and tris-(2-chloro, 1-methylethyl) phosphate (TCIPP) were the most abundant OPEs in sediments, while TCIPP predominated in S. plana. The biota-sediment accumulation factors suggest bioaccumulation potential for chlorinated-OPEs, with higher exposure in summer. No significant correlations were generally found between OPEs and MPs in sediments suggesting a limited role of MPs as in-situ source of OPEs.

The metabolic pathway of clodinafop-propargyl degradation by consortium WP and its bacterial diversity analysis

Clodinafop-propargyl (CP) is a widely used post-emergence aryloxyphenoxy propionate (AOPP) herbicide and causes serious environmental problems. The elimination of CP from the environment is urgently required, but there are few reports on microbial degradation of CP. In this study, a bacterial consortium WP was enriched from the activated sludge of CP containment, which could completely degrade 50 mg L−1 of CP within 7 days. UPLC-MS analysis showed that the main intermediate metabolites of CP degradation were clodinafop acid (CA), 4-(5-chloro-3-fluoro-2-pyridyloxy) phenol, and 5-chloro-3-fluoropyridin-2-ol. And the metabolic pathway of CP degradation by consortium WP has been proposed. High-throughput sequencing revealed that the consortium WP had rich bacterial diversity, including 4 phyla, 14 classes, and 148 genera. Ten bacteria capable of converting CP to CA were isolated from the consortium WP using LB medium containing CP, and the strain Pseudoxanthomonas sp. WP66 had the strongest conversion ability, which could utilize CP as the sole source for growth and degrade 91.20% of 100 mg L−1 CP within 15 h. This study presented the main degradation pathways of CP by microorganisms, and provided resource of bacterial strain for the removal of CP from the environment.

Biodegradation of polyethylene terephthalate (PET) by Brucella intermedia IITR130 and its proposed metabolic pathway.

Accumulation of polyethylene terephthalate (PET) polyester in ecosystems across the globe is a major pollution of concern. Microbial degradation recently generated novel insights into the biodegradation of varieties of plastics. In this study, a PET degrading bacterium Brucella intermedia IITR130 was isolated from a contaminated lake ecosystem at Pallikaranai, Chennai, India. Incubation of the bacterium along with the PET sheet (0.1mm thickness) for 60 days resulted in 26.06% degradation, indicating a half-life of 137.8 days. Considerable changes in the surface morphology of the PET sheet were found as holes, pits, and cracks on incubation with strain IITR130, as revealed by scanning electron microscopy (SEM). After bacterial treatment of PET, the formation of new functional groups, most notably in the area of 3326cm-1 suggestive of O-H stretch, leading to carboxylic acid and alcohol as products were suggested by fourier transform infrared (FTIR) analysis. Monomethyl terephthalate (MMT) and terephthalic acid (TPA) were identified by gas chromatography-mass spectrometry (GC-MS) analysis as PET degradation metabolites. Tributyrin clearance assay confirmed the presence of a lipase/esterase enzyme in the strain IITR130. In this study, a degradation pathway for PET by an isolated and identified bacterium Brucella intermedia IITR130 was characterized in detail.

Safety Assessment of Levilactobacillus brevis KU15006: A Comprehensive Analysis of its Phenotypic and Genotypic Properties.

Levilactobacillus brevis KU15006, isolated from kimchi, exhibits pathogen-antagonistic and anti-diabetic activities; however, the safety of this strain has not been assessed. In the present study, L. brevis KU15006 was evaluated to elucidate its safety as a probiotic strain using phenotypic and genotypic analyses. Its safety was assessed using a minimum inhibitory concentration test comprising nine antibiotics, 26 antibiotic resistance genes, a single conjugative element, virulence gene analysis, hemolysis, cell cytotoxicity, mucin degradation, and toxic metabolite production. L. brevis KU15006 exhibited equal or lower minimum inhibitory concentration for the nine antibiotics than the cut-off value established by the European Food Safety Authority. It did not harbor antibiotic resistance and virulence genes. L. brevis KU15006 lacked β-hemolysis, mucin degradation, cytotoxicity against Caco-2 cells, gelatin liquefaction, bile salt deconjugation, and toxic metabolite production abilities. Based on the results, L. brevis KU15006, which has antagonistic and anti-diabetic effects, could be marketed as a probiotic in the future.

Multifaceted effects of volatile organic compounds released by Fusarium oxysporum on Trichoderma biocontrol agents

We investigated how volatile organic compounds (VOCs) produced by Fusarium oxysporum, a soilborne fungal species complex that infects diverse plants, affect the growth of four Trichoderma spp. and their secretion of antifungal molecules and gene expression to evaluate the involvement of VOC-mediated recognition of pathogens in biocontrol. Five VOCs commonly produced by all F. oxysporum strains analyzed, including 4-ethylanisole, 1-hexanol, 3-methyl-1-butanol, isopentyl acetate, and 2-phenylethanol, were tested. All compounds inhibited Trichoderma growth in a concentration-dependent manner, with 4-ethylanisole being the most effective. Although the degree of growth inhibition by each compound was similar among the four species, their secretion of antifungal molecules varied widely, with the degree of induction in T. virens and T. viride being higher than that in T. harzianum and T. asperellum in most treatments. Transcriptome analyses via RNA-seq after exposure to 4-ethylasniole, 3-methyl-1-butanol, isopentyl acetate, and VOCs released by three F. oxysporum strains were performed. Analysis of gene ontology (GO) terms enriched among the differentially expressed genes (DEGs) revealed that diverse processes, such as synthesizing/metabolizing various types of organic compounds, ion/carbohydrate transport, proteolysis, response to stimulus, signal transduction, chromosome organization, RNA processing, and DNA metabolism, were significantly affected. Some genes likely involved in biocontrol, such as those that perform fungal cell wall degradation, protein hydrolysis, and secondary metabolite biosynthesis, were also differentially regulated. However, the DEGs in the four species did not overlap significantly, suggesting that individual species respond distinctly to each VOC treatment. Collectively, our data suggest that Trichoderma BCAs recognize other fungi through multiple specific volatile cues and prepare for subsequent encounters. We discuss future studies needed to test this hypothesis and to uncover the mechanism underlying the VOC-mediated recognition of pathogens and the resulting modulation of diverse cellular responses.

The kynurenine and serotonin pathway, neopterin and biopterin in depressed children and adolescents: an impact of omega-3 fatty acids, and association with markers related to depressive disorder. A randomized, blinded, prospective study.

https://www.isrctn.com/ISRCTN81655012, identifier ISRCTN81655012.