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Applied and Environmental Microbiology Oct 2023grows as a biofilm under many environmental conditions, and the bacterium can disperse from biofilms via highly regulated, dynamic processes. However, physiologic...
grows as a biofilm under many environmental conditions, and the bacterium can disperse from biofilms via highly regulated, dynamic processes. However, physiologic triggers of biofilm dispersal remain poorly understood. Based on prior literature describing dispersal triggered by forms of starvation, we tested bacterial respiratory inhibitors for biofilm dispersal in two models resembling chronic airway infections. Our underlying hypothesis was that respiratory inhibitors could serve as a model for the downstream effects of starvation. We used two experimental conditions. In the first condition, biofilms were grown and dispersed from the surface of airway epithelial cells, and the second condition was a model where biofilms were grown on glass in cell culture media supplemented with host-relevant iron sources. In both biofilm models, the respiratory inhibitors potassium cyanide and sodium azide each triggered biofilm dispersal. We hypothesized that cyanide-induced dispersal was due to respiratory inhibition rather than signaling via an alternative mechanism, and, indeed, if respiration was supported by overexpression of cyanide-insensitive oxidase, dispersal was prevented. Dispersal required the activity of the cyclic-di-GMP regulated protease LapG, reinforcing the role of matrix degradation in dispersal. Finally, we examined the roles of individual phosphodiesterases, previously implicated in dispersal to specific triggers, and found signaling to be highly redundant. Combined deletion of the phosphodiesterases , , and was required to attenuate the dispersal phenotype. In summary, this work adds insight into the physiology of biofilm dispersal under environmental conditions in which bacterial respiration is abruptly limited. IMPORTANCE The bacterium grows in biofilm communities that are very difficult to treat in human infections. Growing as a biofilm can protect bacteria from antibiotics and the immune system. Bacteria can leave a biofilm through a process called "dispersal." Dispersed bacteria seed new growth areas and are more susceptible to killing by antibiotics. The triggers for biofilm dispersal are not well understood, and if we understood dispersal better it might lead to the development of new treatments for infection. In this paper, we find that inhibiting ability to respire (generate energy) can trigger dispersal from a biofilm grown in association with human respiratory epithelial cells in culture. The dispersal process requires a protease which is previously known to degrade the biofilm matrix. These findings give us a better understanding of how the biofilm dispersal process works so that future research can discover better ways of clearing bacteria growing in biofilms.
Topics: Humans; Pseudomonas aeruginosa; Biofilms; Phosphoric Diester Hydrolases; Anti-Bacterial Agents; Peptide Hydrolases; Cyanides; Gene Expression Regulation, Bacterial; Bacterial Proteins; Cyclic GMP
PubMed: 37728340
DOI: 10.1128/aem.01101-23 -
ACS Omega Aug 2023Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent...
Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent consumption, high slurry pH, and environmental hazards. This work aimed to explore the utilization and mechanisms of tannic acid (TA) as an eco-friendly alternative to lime or cyanide in chalcopyrite-pyrite separation. Flotation results showed that TA selectively depressed pyrite yet allowed chalcopyrite to float at neutral or alkaline pH. Adsorption density and zeta potential results indicated that TA adsorbed intensely on pyrite but minorly on chalcopyrite. Besides, potassium ethyl xanthate was still largely adsorbed on chalcopyrite but not on pyrite after TA adsorption. Surface analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy further showed that the oxidation species of FeOOH and Fe (SO), particularly FeOOH were the main active sites for TA chemical adsorption. Owing to the greater and faster oxidation of pyrite, more FeOOH and Fe (SO) were generated on the pyrite surface, and the chemical adsorption of TA was more pronounced on the pyrite surface than on the chalcopyrite surface.
PubMed: 37636951
DOI: 10.1021/acsomega.3c03663 -
Heliyon Jun 2023Spebrutinib is a new Bruton tyrosine kinase inhibitor developed by Avila Therapeutics and Celgene. Spebrutinib (SPB) is currently in phase Ib clinical trials for the...
Spebrutinib is a new Bruton tyrosine kinase inhibitor developed by Avila Therapeutics and Celgene. Spebrutinib (SPB) is currently in phase Ib clinical trials for the treatment of lymphoma in the United States. Preliminary studies were first performed to predict susceptible sites of metabolism, reactivity pathways and structural alerts for toxicities by StarDrop WhichP450™ module, Xenosite web predictor tool and DEREK software; respectively. SPB metabolites and adducts were characterized from rat liver microsomes (RLM) using LC-MS/MS. Formation of reactive intermediates was investigated using potassium cyanide (KCN), glutathione (GSH) and methoxylamine as trapping nucleophiles for the unstable and reactive iminium, iminoquinone and aldehyde intermediates, respectively, with the aim to produce stable adducts that can be detected and characterized using mass spectrometry. Fourteen phase I metabolites, four cyanide adducts, six GSH adducts and three methoxylamine adducts of SPB were identified and characterized. The proposed metabolic pathways involved in generation of phase I metabolites of SPB are oxidation, hydroxylation, -dealkylation, epoxidation, defluorination and reduction. Several reactive intermediates were identified and characterized, the formation of which can aid in explaining the adverse drug reactions of SPB. Several iminium, 2-iminopyrimidin-5()-one and aldehyde intermediates of SPB were revealed. Acrylamide is identified as a structural alert for toxicity by DEREK report and was found to be involved in the formation of several glycidamide and aldehyde reactive intermediates.
PubMed: 37484253
DOI: 10.1016/j.heliyon.2023.e17058 -
Saudi Pharmaceutical Journal : SPJ :... Oct 2023Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative...
Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative flavonoids in onion. Several antioxidant techniques were used in this investigation to assess the antioxidant capabilities of spiraeoside, including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging, N,N-dimethyl-p-phenylenediamine radical (DMPD) scavenging, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS) scavenging activities, cupric ions (Cu) reducing and potassium ferric cyanide reduction abilities. In contrast, the water-soluble α-tocopherol analogue trolox and the conventional antioxidants butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and α-tocopherol were utilized as the standards for evaluation. Spiraeoside scavenged the DPPH radicals an IC of 28.51 μg/mL (r: 0.9705) meanwhile BHA, BHT, trolox, and α-tocopherol displayed IC of 10.10 μg/mL (r: 0.9015), 25.95 μg/mL (r: 0.9221), 7.059 μg/mL (r: 0.9614) and 11.31 μg/mL (r: 0.9642), accordingly. The results exhibited that spiraeoside had effects similar to BHT, but less potent than α-tocopherol, trolox and BHA. Also, inhibitory effects of spiraeoside were evaluated toward some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II) and α-glycosidase, which are related to a number of illnesses, such as Alzheimer's disease (AD), diabetes mellitus and glaucoma disorder. Spiraeoside exhibited IC values of 4.44 nM (r: 0.9610), 7.88 nM (r: 0.9784), 19.42 nM (r: 0.9673) and 29.17 mM (r: 0.9209), respectively against these enzymes. Enzyme inhibition abilities were compared to clinical used inhibitors including acetazolamide (for CA II), tacrine (for AChE and BChE) and acarbose (for α-glycosidase). Spiraeoside demonstrated effective antioxidant, anticholinergic, antidiabetic and antiglaucoma activities. With these properties, it has shown that Spiraeoside has the potential to be a medicine for some metabolic diseases.
PubMed: 37693735
DOI: 10.1016/j.jsps.2023.101760 -
Enzyme and Microbial Technology Mar 2024Cyanide is widely utilized in the extraction of precious metal extraction even though it has been deemed as the most toxic compound. Fusarium oxysporum has been shown to...
Cyanide is widely utilized in the extraction of precious metal extraction even though it has been deemed as the most toxic compound. Fusarium oxysporum has been shown to degrade cyanide through the activity of the Nitrilase enzyme. In this study, the coding sequence of nitrilase gene from F. oxysporum genomic DNA was optimized for cloning and expression in E. coli. The pUC57 containing synthetic optimized nitrilase gene was transferred into E. coli DH5α strain. This nitrilase gene was sub-cloned into pET26b (+) expression vector containing an in-built His-tag at the C-terminal end to facilitate its purification. The recombinant plasmid, pETAM1, was confirmed by PCR, digestion pattern, and sequencing. The recombinant protein was overproduced in E. coli BL21 (DE3). The results of the SDS-PAGE pattern and Western blot analysis confirmed the expression of the expected recombinant protein. For expression optimization of Nitrilase protein, M16 orthogonal experimental design of the Taguchi method was used. The effect of induction time, temperature and IPTG concentration were examined using four levels for each factors. Estimation of the amount of the expressed protein was calculated via densitometry on SDS-PAGE. The enzyme activity and expression in E. coli proved to be successful since there was ammonia production when potassium cyanide and acrylonitrile were used as substrates while the highest enzyme activity of 88% was expressed at 30 °C. The K and V values of the expressed Nitrilase enzyme were determined to be 0.68 mM and 0.48 mM/min respectively.
Topics: Cloning, Molecular; Escherichia coli; Recombinant Proteins; Cyanides; Aminohydrolases; Fusarium
PubMed: 38134733
DOI: 10.1016/j.enzmictec.2023.110389 -
Life (Basel, Switzerland) Oct 2023Baicalin is the foremost prevalent flavonoid found in . It also frequently occurs in many multi-herbal preparations utilized in Eastern countries. The current research...
Baicalin is the foremost prevalent flavonoid found in . It also frequently occurs in many multi-herbal preparations utilized in Eastern countries. The current research has assessed and compared the antioxidant, antidiabetic, anticholinergic, and antiglaucoma properties of baicalin hydrate. Baicalin hydrate was tested for its antioxidant capacity using a variety of techniques, including N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD) scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS) scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, potassium ferric cyanide reduction ability, and cupric ions (Cu) reducing activities. Also, for comparative purposes, reference antioxidants, such as butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were employed. Baicalin hydrate had an IC value of 13.40 μg/mL (r: 0.9940) for DPPH radical scavenging, whereas BHA, BHT, Trolox, and α-Tocopherol had IC values of 10.10, 25.95, 7.059, and 11.31 μg/mL for DPPH scavenging, respectively. These findings showed that baicalin hydrate had comparably close and similar DPPH scavenging capability to BHA, α-tocopherol, and Trolox, but it performed better than BHT. Additionally, apart from these studies, baicalin hydrate was tested for its ability to inhibit a number of metabolic enzymes, including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which have been linked to several serious illnesses, such as Alzheimer's disease (AD), glaucoma, and diabetes, where the K values of baicalin hydrate toward the aforementioned enzymes were 10.01 ± 2.86, 3.50 ± 0.68, 19.25 ± 1.79, and 26.98 ± 9.91 nM, respectively.
PubMed: 38004276
DOI: 10.3390/life13112136 -
Binucleate induced tomato resistance against via affecting antioxidants and cell wall reinforcement.Heliyon Mar 2024Isolates of (AG-3 PT, AG-4 HG-I, AG-4 HG-II) and one binucleate sp. (BNR) belonging to AG-Bb were investigated for pathogenicity on tomato cultivar Mobil. The BNR...
Isolates of (AG-3 PT, AG-4 HG-I, AG-4 HG-II) and one binucleate sp. (BNR) belonging to AG-Bb were investigated for pathogenicity on tomato cultivar Mobil. The BNR isolate revealed the lowest virulence and it was used as biocontrol agent against AG-4 HG-II, which showed the highest virulence on tomato. Inoculation of tomato plants with the hypovirulent BNR isolate reduced the disease symptoms of and induced resistance. Resistance induction was observed not only on the plants simultaneously inoculated with BNR and , but also when the plants were inoculated by the BNR and with time intervals. The peroxidase (POX), superoxide dismutase (SOD) and catalase (CAT) activities and expression levels of the corresponding genes in tomato plants increased after or BNR inoculation. The highest level of antioxidant activities and expression of their genes, lignin and callose formation were observed in the plants inoculated with the BNR and , simultaneously. The BNR inoculation reduced HO accumulation. The highest level of priming was observed for the POX among other antioxidants tested via application of the BNR. Treatment with potassium cyanide (as a POX inhibitor) reduced basal resistance and BNR-induced resistance (BNR-IR) via reduction of lignification and callose deposition in tomato plants. These findings demonstrated the role of antioxidant enzymes, mainly the POX, in both basal resistance and BNR-IR. Therefore, redox state and antioxidants are involved in cell wall strengthening via lignin and callose formation, as important defense components which decrease the pathogen progress in plant tissues.
PubMed: 38545156
DOI: 10.1016/j.heliyon.2024.e27881 -
Journal of Fungi (Basel, Switzerland) Nov 2023This study analyzed the role of blood serum in enhancing the mitochondrial metabolism and virulence of Mucorales through rhizoferrin secretion. We observed that the...
This study analyzed the role of blood serum in enhancing the mitochondrial metabolism and virulence of Mucorales through rhizoferrin secretion. We observed that the spores of clinically relevant Mucorales produced in the presence of serum exhibited higher virulence in a heterologous infection model of . Cell-free supernatants of the culture broth obtained from spores produced in serum showed increased toxicity against , which was linked with the enhanced secretion of rhizoferrin. Spores from Mucoralean species produced or germinated in serum showed increased respiration rates and reactive oxygen species levels. The addition of non-lethal concentrations of potassium cyanide and N-acetylcysteine during the aerobic or anaerobic growth of Mucorales decreased the toxicity of the cell-free supernatants of the culture broth, suggesting that mitochondrial metabolism is important for serum-induced virulence. In support of this hypothesis, a mutant strain of that lacks fermentation and solely relies on oxidative metabolism exhibited virulence levels comparable to those of the wild-type strain under serum-induced conditions. Contrary to the lower virulence observed, even in the serum, the ADP-ribosylation factor-like 2 deletion strain exhibited decreased mitochondrial activity. Moreover, spores produced in the serum of and that grew in the presence of a mitophagy inducer showed low virulence. These results suggest that serum-induced mitochondrial activity increases rhizoferrin levels, making Mucorales more virulent.
PubMed: 38132728
DOI: 10.3390/jof9121127 -
Frontiers in Plant Science 2023The chemical composition, insect antifeedant, nematicidal activity, phytotoxicity, and nematicidal activity of the essential oil (EO) of the African medicinal plant...
The chemical composition, insect antifeedant, nematicidal activity, phytotoxicity, and nematicidal activity of the essential oil (EO) of the African medicinal plant were studied. Chemical analysis using GC/MS indicated that benzyl isothiocyanate (96.23%) was the major compound, followed by benzyl cyanide (1.38%). The biocidal effects of this oil were tested against insect pests and root-knot nematodes. All the insect species tested were significantly affected by the oil according to their feeding adaptations ( and were less affected than ) with efficient doses (EC) of 29.4 8.3 μg/cm, 14.744 8.3 μg/cm, and 8.3 μg/cm, respectively. The oil was highly effective against juveniles J2 of the nematode , with LC-LC values of 0.007 mg/mL-0.0113 mg/mL. EO at minimum lethal concentrations (MLC) and below strongly inhibited egg hatching , whereas soil treatment caused a strong suppression of nematode population, infection frequency, and multiplication rate. The EO inhibited ryegrass () germination at 0.4 mg/mL, while at 0.1 mg/mL, its effects on germination, root and leaf growth were moderate (32.4%, 8.4%, and 18.3%, respectively). The tomato () germination was not affected by the EO, but the root growth was reduced (56% at 0.1 mg/mL) at a dose 10 times higher than the LD calculated for J2 mortality. Molecular docking of the nematicidal effects of the oil using PyRx revealed a strong interaction between potassium chloride transporting KCC3 (PDB ID: 7D90) and benzyl cyanide at a distance of 2.20 A° with GLN C:350, followed by benzyl isothiocyanate at a distance of 2.78 A° with ARG B:294. The nematicidal effects of EO on penetration and reproduction in tomato roots further support the potential of this EO as a nematicidal agent with insect antifeedant effects, which could be used by local farmers for crop protection.
PubMed: 38098790
DOI: 10.3389/fpls.2023.1260360