scholarly journals Green Synthesis of Iron Nanoparticles from Spinach Leaf and Banana Peel Aqueous Extracts and Evaluation of Antibacterial Potential

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Pankaj Kumar Tyagi ◽  
Samridhi Gupta ◽  
Shruti Tyagi ◽  
Manoj Kumar ◽  
R. Pandiselvam ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Iron Nanoparticles ◽  
Spinacia Oleracea ◽  
Control Sample ◽  
Banana Peel ◽  
Aqueous Extracts ◽  
E Coli ◽  
Spinach Leaf ◽  
Antibacterial Potential

Spinacia oleracea (spinach) and Musa acuminata (banana) were chosen for the study, and aqueous extracts of spinach leaf extract (SLE) and banana peel extract (BPE) were prepared for the synthesis of iron nanoparticles (FeNPs), and their antibacterial potential against pathogenic bacteria Bacillus subtilis (MTTC 1133) and Escherichia coli (MTTC 62) was evaluated. In 10 minutes at 60°C, the color of the mixture (FeCl3+SLE) changed from light green to dark blackish-brown, and the color of the mix (FeCl3+BPE) changed from transparent yellow to dark black, confirming the synthesis of FeNPs from SLE and BPE, respectively. The UV-Vis spectra of spinach- and banana-derived FeNPs revealed two peaks ranging from 240 to 430 nm and multiple peaks at 240, 270, and 395 nm, respectively. FTIR spectroscopy was used to show different functional groups on BPE and SLE, and their role in FeNP synthesis was predicted. TEM micrographs showed that the particles were in nanoscale, ranging in size from 20 to 50 nm for BPE-derived FeNPs and 10 to 70 nm for SLE-derived FeNPs. The FeNP (BPE and SLE) XRD analysis revealed amorphism, with a weak iron characteristic peak, indicating noncrystallinity. The antibacterial potential of BPE- and SLE-FeNPs was investigated, and inhibition zones (mm) against B. subtilis ( 22.70 ± 0.4 ) and E. coli ( 20.45 ± 1.66 ) were observed, as well as SLE-FeNPs against B. subtilis ( 23.56 ± 1.00 ) and E. coli ( 20.33 ± 0.58 ). There were no significant differences in antibacterial activities between BPE-FeNPs and SLE-FeNPs. Positive controls were tetracycline and gentamicin, both standard antibiotics, at 5 μg/disk. SLE- and BPE-derived green FeNPs were also analysed in vivo of D. melanogaster life history traits, i.e., fecundity, hatchability, viability, and duration of development for toxicity evaluation. SLE- and BPE-derived green FeNPs at a concentration of 10 mg/L were fed flies compared to normal diet-fed flies (control sample), and no significant differences were observed between them. The findings suggest that FeNPs have a high antibacterial potential and could be used as antibacterial agents against pathogenic bacteria while being nontoxic in nature.

scholarly journals Site-specific serine phosphorylation of spinach leaf sucrose-phosphate synthase

1992 ◽  
Vol 283 (3) ◽  
pp. 877-882 ◽  
Author(s):  
J L A Huber ◽  
S C Huber
Keyword(s):  
Okadaic Acid ◽  
Spinacia Oleracea ◽  
Sucrose Phosphate Synthase ◽  
Serine Phosphorylation ◽  
Spinacia Oleracea L ◽  
Spinach Leaf ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

We recently reported [Huber, Huber & Nielsen (1989) Arch. Biochem. Biophys. 270, 681-690] that spinach (Spinacia oleracea L.) sucrose-phosphate synthase (SPS; EC 2.4.1.14) was phosphorylated in vivo when leaves were fed [32P]Pi. In vitro the enzyme was phosphorylated and inactivated by using [gamma-32P]ATP. We now report that SPS is phosphorylated both in vivo and in vitro on serine residues. The protein is phosphorylated at multiple sites both in vivo and in vitro as indicated by two-dimensional peptide maps of the immunopurified SPS protein. After being fed with radiolabel, leaves were illuminated or given mannose (which activates the enzyme), in the presence or absence of okadaic acid. Feeding okadaic acid to leaves decreased the SPS activation state in the dark and light and in leaves fed mannose. Across all the treatments, the activation state of SPS in situ was inversely related to the labelling of two phosphopeptides (designated phosphopeptides 5 and 7). These two phosphopeptides are phosphorylated when SPS is inactivated in vitro with [gamma-32P]ATP, and thus are designated as regulatory (inhibitory) sites [Huber & Huber (1991) Biochim. Biophys. Acta 1091, 393-400]. Okadaic acid increased the total 32P-labelling of SPS and in particular increased labelling of the two regulatory sites, which explains the decline in activation state. In the presence of okadaic acid, two cryptic phosphorylation sites became labelled in vivo that were not apparent in the absence of the inhibitor. Overall, the results suggest that light/dark regulation of SPS activity occurs as a result of regulatory serine phosphorylation. Multiple sites are phosphorylated in vivo, but two sites in particular appear to regulate activity and dephosphorylation of these sites in vivo is sensitive to okadaic acid.

scholarly journals Widespread Distribution in Pathogenic Bacteria of Di-Iron Proteins That Repair Oxidative and Nitrosative Damage to Iron-Sulfur Centers

2008 ◽  
Vol 190 (6) ◽  
pp. 2004-2013 ◽  
Author(s):  
Tim W. Overton ◽  
Marta C. Justino ◽  
Ying Li ◽  
Joana M. Baptista ◽  
Ana M. P. Melo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Nitrosative Stress ◽  
Human Pathogens ◽  
Paramagnetic Resonance ◽  
Widespread Distribution ◽  
Iron Proteins ◽  
E Coli

ABSTRACT Expression of two genes of unknown function, Staphylococcus aureus scdA and Neisseria gonorrhoeae dnrN, is induced by exposure to oxidative or nitrosative stress. We show that DnrN and ScdA are di-iron proteins that protect their hosts from damage caused by exposure to nitric oxide and to hydrogen peroxide. Loss of FNR-dependent activation of aniA expression and NsrR-dependent repression of norB and dnrN expression on exposure to NO was restored in the gonococcal parent strain but not in a dnrN mutant, suggesting that DnrN is necessary for the repair of NO damage to the gonococcal transcription factors, FNR and NsrR. Restoration of aconitase activity destroyed by exposure of S. aureus to NO or H2O2 required a functional scdA gene. Electron paramagnetic resonance spectra of recombinant ScdA purified from Escherichia coli confirmed the presence of a di-iron center. The recombinant scdA plasmid, but not recombinant plasmids encoding the complete Escherichia coli sufABCDSE or iscRSUAhscBAfdx operons, complemented repair defects of an E. coli ytfE mutant. Analysis of the protein sequence database revealed the importance of the two proteins based on the widespread distribution of highly conserved homologues in both gram-positive and gram-negative bacteria that are human pathogens. We provide in vivo and in vitro evidence that Fe-S clusters damaged by exposure to NO and H2O2 can be repaired by this new protein family, for which we propose the name repair of iron centers, or RIC, proteins.

scholarly journals EVALUATION OF ANTIOXIDANT AND ANTIBACTERIAL POTENTIAL OF ZANTHOXYLUM ALATUM FRUIT AND LEAVES EXTRACTS AGAINST SELECTED PATHOGENIC BACTERIA

2021 ◽  
Vol 37 (1) ◽  
pp. 36-41
Author(s):  
A. Sharif ◽  
H. Javed ◽  
A. Ali ◽  
I. Ahmed ◽  
F. N. Khoso
Keyword(s):  
Antioxidant Activity ◽  
Liquid Medium ◽  
Pathogenic Bacteria ◽  
Diffusion Method ◽  
Fruit Extract ◽  
E Coli ◽  
Medical Needs ◽  
Ic50 Values ◽  
Zones Of Inhibition ◽  
Antibacterial Potential

Zanthoxylum alatum (Z. alatum), an important medicinal plant is used for various ailments including chest infection, cough, cholera, fever, stomach disorders, gas problems, indigestion, piles, toothache, gum problems, dyspepsia and stomachic worldwide. Keeping in view the medicinal potential of this plant, fruit and leaves methanolic (MeOH) extracts were prepared, evaluated for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and for antibacterial potential by well diffusion and macrodilution methods in-vitro. Our results confirmed that Z. alatum fruit and leaves extracts have significant antioxidant activity with IC50 values 0.28 ± 0.07 mg/ml and 0.34 ± 0.05 mg/ml, respectively. The inhibitory trend at highest tested concentration (120 mg/ml) at 24 hr incubation in well diffusion method was recorded as 0.39, 0.30, 0.28, 0.27 and 0.18 cm against S. pyogenes, B. cereus, E. coli, S. aureus and S. enterica for leaf extract, respectively. In case of fruit extract inhibitory trend at highest tested concentration was observed as 0.33, 0.32, 0.31, 0.30 and 0.28 cm against S. aureus, S. enterica, S. pyogenes, B. cereus and E. coli, respectively. The fruit extract showed higher zones of inhibition than leaves extracts against all the test bacteria except S. pyogenes. Moreover, highest zones of inhibition were observed at lowest incubation (24 hr) and lowest zones were observed at highest incubation period (72 hr) for all tested concentrations. Macrodilution method showed antibacterial susceptibility in liquid medium with different levels of IC50 values ranging from 1.6±0.13 mg/ml to 10.3±0.7 5mg/ml. Interestingly, none of the tested bacteria showed resistance against any of the test extract in well diffusion or macrodilution method expressing the Z. alatum as potent candidates to kill bacteria in semisolid or in liquid medium to fulfill medical needs in future.

scholarly journals Antibacterial Potential of Ethanolic and Aqueous Extracts of Carica papaya Leaves

2020 ◽  
pp. 33-38 ◽  
Author(s):  
Augustine I. Airaodion ◽  
John A. Ekenjoku ◽  
Ime U. Akaninyene ◽  
Anthony U. Megwas
Keyword(s):  
Aqueous Extract ◽  
Carica Papaya ◽  
Ethanolic Extract ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Aqueous Extracts ◽  
Filter Paper Disc ◽  
E Coli ◽  
Zones Of Inhibition ◽  
Antibacterial Potential

Background: The search for newer sources of antibiotics is a global challenge pre-occupying research institutions, pharmaceutical companies and academia, since many infectious agents are becoming resistant to synthetic drugs. Aim: This present study sought to investigate the antibacterial potential of ethanolic and aqueous extracts of Carica papaya leaves. Materials and Methods: Fresh and healthy leaves of C. papaya were harvested, air dried and milled into powder. The powder was extracted using ethanol and water as solvents. The antibacterial activities of both extracts were determined by diffusion method. Nutrient agar medium was prepared using standard method. Pure cultures of Coliform bacillus, Staphylococcus epidermidis, Streptococcus viridans, Salmonella typhi and Escherichia coli were obtained from the Department of Veterinary Microbiology and Parasitology, Federal University of Agriculture, Abeokuta, Nigeria. The extracts were serially diluted to obtain 1.0%, 0.5%, 0.25% and 0.125% solutions in sterile test tubes. Sterilized 9 mm filter paper disc soaked in the diluted extracts were placed on the plate and incubated for 24 hours at room temperature. The plates were examined for clear zones of inhibition. Presence of zones of inhibition indicated activity. Results: the results showed that both ethanolic and aqueous extracts of C. papaya leaves exhibit antibacterial activities against C. bacillus, S. epidemidis, S. viridans and E. coli and also inhibited their growth. The effect of the ethanolic extract was greater than that of the aqueous extract. However, this activity was not observed with S. typhi. Conclusion: The result of the present study showed that C. papaya leaves might effectively inhibit the growth of C. bacillus, S. epidemidis, S. viridans and E. coli but not that of S. typhi. However, the ethanolic extract is more potent than the aqueous extract.

scholarly journals Evolutionary Adaptation of an AraC-Like Regulatory Protein in Citrobacter rodentium and Escherichia Species

2015 ◽  
Vol 83 (4) ◽  
pp. 1384-1395 ◽  
Author(s):  
Aimee Tan ◽  
Nicola K. Petty ◽  
Dianna Hocking ◽  
Vicki Bennett-Wood ◽  
Matthew Wakefield ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Regulatory Protein ◽  
Gene Repertoire ◽  
Citrobacter Rodentium ◽  
Environmental Strain ◽  
Content Type ◽  
E Coli ◽  
Genes Encoding

The evolution of pathogenic bacteria is a multifaceted and complex process, which is strongly influenced by the horizontal acquisition of genetic elements and their subsequent expression in their new hosts. A well-studied example is the RegA regulon of the enteric pathogenCitrobacter rodentium. The RegA regulatory protein is a member of the AraC/XylS superfamily, which coordinates the expression of a gene repertoire that is necessary for full pathogenicity of this murine pathogen. Upon stimulation by an exogenous, gut-associated signal, namely, bicarbonate ions, RegA activates the expression of a series of genes, including virulence factors, such as autotransporters, fimbriae, a dispersin-like protein, and thegrlRAoperon on the locus of enterocyte effacement pathogenicity island. Interestingly, the genes encoding RegA homologues are distributed across the genusEscherichia, encompassing pathogenic and nonpathogenic subtypes. In this study, we carried out a series of bioinformatic, transcriptional, and functional analyses of the RegA regulons of these bacteria. Our results demonstrated thatregAhas been horizontally transferred toEscherichiaspp. andC. rodentium. Comparative studies of two RegA homologues, namely, those fromC. rodentiumandE. coliSMS-3-5, a multiresistant environmental strain ofE. coli, showed that the two regulators acted similarlyin vitrobut differed in terms of their abilities to activate the virulence ofC. rodentiumin vivo, which evidently was due to their differential activation ofgrlRA. Our data indicate that RegA fromC. rodentiumhas strain-specific adaptations that facilitate infection of its murine host. These findings shed new light on the development of virulence byC. rodentiumand on the evolution of virulence-regulatory genes of bacterial pathogens in general.

scholarly journals Role of Host Xanthine Oxidase in Infection Due to Enteropathogenic and Shiga-Toxigenic Escherichia coli

2013 ◽  
Vol 81 (4) ◽  
pp. 1129-1139 ◽  
Author(s):  
John K. Crane ◽  
Tonniele M. Naeher ◽  
Jacqueline E. Broome ◽  
Edgar C. Boedeker
Keyword(s):  
Escherichia Coli ◽  
Xanthine Oxidase ◽  
Host Defense ◽  
Pathogenic Bacteria ◽  
Intestinal Cell ◽  
Intestinal Loop ◽  
Loop Model ◽  
Content Type ◽  
E Coli

ABSTRACTXanthine oxidase (XO), also known as xanthine oxidoreductase, has long been considered an important host defense molecule in the intestine and in breastfed infants. Here, we present evidence that XO is released from and active in intestinal tissues and fluids in response to infection with enteropathogenicEscherichia coli(EPEC) and Shiga-toxigenicE. coli(STEC), also known as enterohemorrhagicE. coli(EHEC). XO is released into intestinal fluids in EPEC and STEC infection in a rabbit animal model. XO activity results in the generation of surprisingly high concentrations of uric acid in both cultured cell and animal models of infection. Hydrogen peroxide (H2O2) generated by XO activity triggered a chloride secretory response in intestinal cell monolayers within minutes but decreased transepithelial electrical resistance at 6 to 22 h. H2O2generated by XO activity was effective at killing laboratory strains ofE. coli, commensal microbiotas, and anaerobes, but wild-type EPEC and STEC strains were 100 to 1,000 times more resistant to killing or growth inhibition by this pathway. Instead of killing pathogenic bacteria, physiologic concentrations of XO increased virulence by inducing the production of Shiga toxins from STEC strains.In vivo, exogenous XO plus the substrate hypoxanthine did not protect and instead worsened the outcome of STEC infection in the rabbit ligated intestinal loop model of infection. XO released during EPEC and STEC infection may serve as a virulence-inducing signal to the pathogen and not solely as a protective host defense.

scholarly journals INHIBITORY EFFECTS OF POD EXTRACT OF ACACIA NILOTICA AGAINST SOME PATHOGENIC BACTERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 183-189
Author(s):  
Joseph Odewade ◽  
Albert Fasogbon ◽  
Olawale Afolabi
Keyword(s):  
Crude Extract ◽  
Pathogenic Bacteria ◽  
Fine Powder ◽  
Acacia Nilotica ◽  
In Vivo Studies ◽  
Inhibitory Effects ◽  
Zone Of Inhibition ◽  
Potential Minimum ◽  
Antibacterial Potential

This study assessed the inhibitory effects of the pod extract of Acacia nilotica against some pathogenic bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococccus pyogenes). Fresh pods of Acacia nilotica were air-dried and then ground into fine powder. Thereafter, pod powder was extracted using ethanol and distilled water in the ratio 3 to 2 (v/v). The crude extract was concentrated in vacuo and lyophilized. Afterwards, screened for phytochemicals and tested for antibacterial activity against the bacterial isolates. Antibacterial potential, minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC) of the extract were determined using standard microbiological method. Zone of inhibition shown by the crude extract at 50 mg/mL on the isolates ranged between 10 mm and 18 mm while MIC ranged between 1.56 mg/mL and 25 mg/mL. Minimum bactericidal concentrations ranged between 3.13 mg/mL and 50.00 mg/mL. The phytochemical screening of the extract revealed the presence of tannins, alkaloids, flavonoids, saponins and cardiac glycosides. This study, therefore, showed that pod extract of Acacia nilotica exhibited appreciable inhibitory effects on the test isolates. Hence, there is need for in vivo studies to complement the present findings.

scholarly journals Mechanism of action of oxazolidinones: effects of linezolid and eperezolid on translation reactions.

1997 ◽  
Vol 41 (10) ◽  
pp. 2132-2136 ◽  
Author(s):  
D L Shinabarger ◽  
K R Marotti ◽  
R W Murray ◽  
A H Lin ◽  
E P Melchior ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Pathogenic Bacteria ◽  
Coli Strain ◽  
In Vitro Translation ◽  
E Coli ◽  
Initiation Phase ◽  
New Class ◽  
Bacterial Translation

The oxazolidinones are a new class of synthetic antibiotics with good activity against gram-positive pathogenic bacteria. Experiments with a susceptible Escherichia coli strain, UC6782, demonstrated that in vivo protein synthesis was inhibited by both eperezolid (formerly U-100592) and linezolid (formerly U-100766). Both linezolid and eperezolid were potent inhibitors of cell-free transcription-translation in E. coli, exhibiting 50% inhibitory concentrations (IC50s) of 1.8 and 2.5 microM, respectively. The ability to demonstrate inhibition of in vitro translation directed by phage MS2 RNA was greatly dependent upon the amount of RNA added to the assay. For eperezolid, 128 microg of RNA per ml produced an IC50 of 50 microM whereas a concentration of 32 microg/ml yielded an IC50 of 20 microM. Investigating lower RNA template concentrations in linezolid inhibition experiments revealed that 32 and 8 microg of MS2 phage RNA per ml produced IC50s of 24 and 15 microM, respectively. This phenomenon was shared by the translation initiation inhibitor kasugamycin but not by streptomycin. Neither oxazolidinone inhibited the formation of N-formylmethionyl-tRNA, elongation, or termination reactions of bacterial translation. The oxazolidinones appear to inhibit bacterial translation at the initiation phase of protein synthesis.

Escherichia coli O157:H7 Populations in Ruminants Can Be Reduced by Orange Peel Product Feeding†

2011 ◽  
Vol 74 (11) ◽  
pp. 1917-1921 ◽  
Author(s):  
TODD R. CALLAWAY ◽  
JEFFERY A. CARROLL ◽  
JOHN D. ARTHINGTON ◽  
TOM S. EDRINGTON ◽  
MICHELLE L. ROSSMAN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Intervention Strategy ◽  
Orange Peel ◽  
Escherichia Coli O157 ◽  
Citrus Peel ◽  
Fecal Shedding ◽  
E Coli ◽  
Foodborne Pathogenic Bacteria

Foodborne pathogenic bacteria such as Escherichia coli O157:H7 are threats to the safety of beef. Citrus peel and dried orange pulp are by-products from citrus juice production that have natural antimicrobial effects and are often incorporated into least-cost ration formulations for beef and dairy cattle. This study was designed to determine if orange peel and pulp affected E. coli O157:H7 populations in vivo. Sheep (n = 24) were fed a cracked corn grain–based diet that was supplemented with a 50-50 mixture of dried orange pellet and fresh orange peel to achieve a final concentration (dry matter basis, wt/wt) of 0, 5, or 10% pelleted orange peel (OP) for 10 days. Sheep were artificially inoculated with 1010 CFU of E. coli O157:H7 by oral dosing. Fecal shedding of E. coli O157:H7 was measured daily for 5 days after inoculation, after which all animals were humanely euthanized. At 96 h postinoculation, E. coli O157:H7 shedding was reduced (P < 0.05) in sheep fed 10% OP. Populations of inoculated E. coli O157:H7 were reduced by OP treatment throughout the gastrointestinal tract; however, this reduction reached significant levels in the rumen (P < 0.05) of sheep fed 10% OP diets. Cecal and rectal populations of E. coli O157:H7 were reduced (P <0.05) by inclusion of both 5 and 10% OP diets. Our results demonstrate that orange peel products can be used as a preharvest intervention strategy as part of an integrated pathogen reduction scheme.

The Bacillus subtilis PriA winged helix domain is critical for surviving DNA damage

2022 ◽  
Author(s):  
Lindsay A. Matthews ◽  
Lyle A. Simmons
Keyword(s):  
Dna Damage ◽  
Dna Binding ◽  
Replication Fork ◽  
Pathogenic Bacteria ◽  
Replication Forks ◽  
Human Pathogens ◽  
Winged Helix ◽  
E Coli ◽  
Stalled Replication Forks

DNA replication forks regularly encounter lesions or other impediments that result in a blockage to fork progression. PriA is one of the key proteins used by virtually all eubacteria to survive conditions that result in a blockage to replication fork movement. PriA directly binds stalled replication forks and initiates fork restart allowing for chromosomes to be fully duplicated under stressful conditions. We used a CRISPR-Cas gene editing approach to map PriA residues critical for surviving DNA damage induced by several antibiotics in B. subtilis . We find that the winged helix (WH) domain in B. subtilis PriA is critical for surviving DNA damage and participates in DNA binding. The critical in vivo function of the WH domain mapped to distinct surfaces that were also conserved among several Gram-positive human pathogens. In addition, we identified an amino acid linker neighboring the WH domain that is greatly extended in B. subtilis due to an insertion. Shortening this linker induced a hypersensitive phenotype to DNA damage, suggesting that its extended length is critical for efficient replication fork restart in vivo . Because the WH domain is dispensable in E. coli PriA, our findings demonstrate an important difference in the contribution of the WH domain during fork restart in B. subtilis . Further, with our results we suggest that this highly variable region in PriA could provide different functions across diverse bacterial organisms. IMPORTANCE PriA is an important protein found in virtually all bacteria that recognizes stalled replication forks orchestrating fork restart. PriA homologs contain a winged helix (WH) domain which is dispensable in E. coli and functions in a fork restart pathway that is not conserved outside of E. coli and closely related proteobacteria. We analyzed the importance of the WH domain and an associated linker in B. subtilis and found that both are critical for surviving DNA damage. This function mapped to a small motif at the C-terminal end of the WH domain, which is also conserved in pathogenic bacteria. The motif was not required for DNA binding and therefore may perform a novel function in the replication fork restart pathway.

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