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Chitosan nanoparticles (CSNP) with an average size of 25.67 nm were synthesized via a novel wet chemical route and characterized using scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. Comparative antibacterial assays of Chitosan NP suspensions prepared in water (at neutral pH) and in dilute acetic acid and chitosan gel prepared in dilute acetic acid/hydrochloric acid (all at concentrations up to 1%) were performed against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria using spread plate method. A parallel viability test was conducted to confirm the presence of surviving cells in the bulk test volume. Minimum bactericidal concentration (MBC) of chitosan gel was 0.5 mg/ml for the bulk chitosan dissolved in 0.05% v/v aq. acetic acid and 0.1 mg/ml for chitosan dissolved in 0.01% v/v aqueous (aq.) hydrochloric acid. In comparison, Chitosan NP were found to be growth promoter at neutral pH and exhibited cell protective efficacy in presence of aq. acetic acid. The biocidal activity of chitosan gel in acidic media was higher when prepared in strong inorganic acid, that is, aq. HCl in comparison with the gel prepared in a relatively weak organic acid that is, aq. CH3COOH at the same concentration. Antibacterial action also showed pH dependence with higher activity at lower pH. However, respective aq. acids also gave comparable bactericidal action; indicating that chitosan may not have any inherent antibacterial property and basically it acts as a growth promoter. [ABSTRACT FROM AUTHOR]

Antibacterial efficacy of chitosan-capped copper oxide nanoparticles (CuO–CS NPs) was evaluated against the Gram-negative bacteria (E. coli) and Gram-positive bacteria (B. subtilis). Comparative antibacterial activity evaluation was performed for CuO–CS NPs, nano Cu(OH)2, nano silver, CuO, and CuSO4.5H2O salt. Miles and Misra method and the spread plate CFU count method were used to enumerate cell counts for antibacterial activity evaluation. The spread plate colony forming unit (CFU) count method is preferable because of its reliability and accuracy. The minimum bactericidal concentration (MBC) of CuO–CS NPs were determined to be 2 µg/ml for E. coli and 12.5 µg/ml for B. subtilis. The values were comparable to those obtained for AgNPs. Moreover, in kinetic study these NPs showed the ability to decontaminate 2 × 105 CFU/ml of E. coli within 2 h at a concentration of 10 μg/ml and 3 × 105 CFU/ml of B. subtilis within 4 h at a concentration of 20 μg/ml. The potential application of synthesized CuO-CS NPS as an effective antibacterial nanocoating on fabrics was also demonstrated by using both qualitative and quantitative test methods. [ABSTRACT FROM AUTHOR]

Costly complex media components such as yeast extract and peptone are still widely used in industrial bioprocesses, despite their ill‐defined composition. Side stream products such as corn steep liquor (CSL) present a compelling economical alternative that contains valuable nutrients required for microbial growth, that is, nitrogen and amino acids, but also vitamins, trace elements, and other minerals. However, as a side stream product, CSL may be subject to batch‐to‐batch variations and compositional heterogeneity. In this study, the Respiration Activity MOnitoring System designed for shake flasks (RAMOS) and 96‐well microtiter plates (μTOM) were applied to investigate the potential and constraints of CSL utilization for two model microorganisms: E. coli and B. subtilis. Considering the dry substance content of complex nutrients involved, CSL‐based media are more efficient in biomass production than the common lysogeny broth (LB) medium, containing 5 g/L yeast extract, 10 g/L peptone, and 5 g/L NaCl. At a glucose to CSL (glucose/CSL, g/g) ratio of 1/1 (g/g) and 2/1 (g/g), a secondary substrate limitation occurred in E. coli and B. subtilis cultivations, respectively. The study sheds light on differences in the metabolic activity of the two applied model organisms between varying CSL batches, which relate to CSL origin and production process, as well as the effect of targeted nutrient supplementation. Through a targeted nutrient supplementation, the most limiting component of the CSL‐glucose medium used for these applied model microorganisms was identified to be ammonium nitrogen. This study proves the suitability of CSL as an alternative nutrient source for E. coli and B. subtilis. The RAMOS and μTOM technique detected differences between CSL batches, allowing easy and early identification of varying batches. A consistent performance of the CSL batches in E. coli and B. subtilis cultivations was demonstrated. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV)-excited visible fluorescence is an attractive option for low-cost, low-complexity, rapid imaging of bacterial and fungal samples for imaging diagnostics in the biomedical community. While several studies have shown there is potential for identification of microbial samples, very little quantitative information is available in the literature for the purposes of diagnostic design. In this work, two non-pathogenic bacteria samples (E. coli pYAC4, and B. subtilis PY79) and a wild-cultivated green bread mold fungus sample are characterized spectroscopically for the purpose of diagnostic design. For each sample, fluorescence spectra excited with low-power near-UV continuous wave (CW) sources, and extinction and elastic scattering spectra are captured and compared. Absolute fluorescence intensity per cell excited at 340 nm is estimated from imaging measurements of aqueous samples. The results are used to estimate detection limits for a prototypical imaging experiment. It was found that fluorescence imaging is feasible for as few as 35 bacteria cells (or ∼ 30 µm3 of bacteria) per pixel, and that the fluorescence intensity per unit volume is similar for the three samples tested here. A discussion and model of the mechanism of bacterial fluorescence in E. coli is provided. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important emerging zoonotic pathogen that causes severe skin infections. To combat infections from drug-resistant bacteria, the transplantation of commensal antimicrobial bacteria as a therapeutic has shown clinical promise. We screened a collection of diverse staphylococcus species from domestic dogs and cats for antimicrobial activity against MRSP. A unique strain (S. felis C4) was isolated from feline skin that inhibited MRSP and multiple gram-positive pathogens. Whole genome sequencing and mass spectrometry revealed several secreted antimicrobials including a thiopeptide bacteriocin micrococcin P1 and phenol-soluble modulin beta (PSMβ) peptides that exhibited antimicrobial and anti-inflammatory activity. Fluorescence and electron microscopy revealed that S. felis antimicrobials inhibited translation and disrupted bacterial but not eukaryotic cell membranes. Competition experiments in mice showed that S. felis significantly reduced MRSP skin colonization and an antimicrobial extract from S. felis significantly reduced necrotic skin injury from MRSP infection. These findings indicate a feline commensal bacterium that could be utilized in bacteriotherapy against difficult-to-treat animal and human skin infections.

Microorganisms promoted corrosion has caused significant loss to marine engineering and the antibacterial coatings have served as a solution that has gained attention. In this study, the chemical vapour deposition technique has been employed to grow three different types of diamond coatings, namely, ultrananocrystalline diamond (UNCD), nanocrystalline diamond (NCD), and microcrystalline diamond (MCD) coatings. The evolution of associated surface morphology and the surface functional groups of the grown coatings have demonstrated antibacterial activity in seawater environments. It is found that different ratio of sp3/sp2 carbon bonds on the diamond coatings influences their surface property (hydrophobic/hydrophilic), which changes the anti-adhesion behaviour of diamond coatings against bacteria. This plays a critical role in determining the antibacterial property of the developed coatings. The results show that the diamond coatings arising from the deposition process kill the bacteria via a combination of the mechanical effects and the functional groups on the surface of UNCD, NCD, and MCD coatings, respectively. These antibacterial coatings are effective to both Gram-negative bacteria (E. coli) and Gram-positive bacteria (B. subtilis) for 1–6 h of incubation time. When the contact duration is prolonged to 6 h or over, the MCD coatings begin to reduce the bacteria colonies drastically and enhance the bacteriostatic rate for both E. coli and B. subtilis.

The development of efficient, eco-friendly antimicrobial agents for air purification and disinfection addresses public health issues connected to preventing airborne pathogens. Herein, the antimicrobial activity of a nanoemulsion (control, 5%, 10%, and 15%) containing neem and lavender oils with polycaprolactone (PCL) was investigated against airborne bacteria, including Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Various parameters such as the physicochemical properties of the nanoemulsion, pH, droplet size, the polydispersity index (PDI), the minimum inhibitory concentration (MIC), the minimum bacterial concentration (MBC), and the color measurement of the emulsion have been evaluated and optimized. Our results showed that the antimicrobial activity of PCL combined with neem and lavender oil was found to be the highest MIC and MBC against all tested bacteria. The droplet sizes for lavender oil are 21.86–115.15 nm, the droplet sizes for neem oil are 23.92–119.15 nm, and their combination is 25.97–50.22 nm. The range of pH and viscosity of nanoemulsions of various concentrations was found to be 5.8 to 6.6 pH and 0.372 to 2.101 cP. This study highlights the potential of nanotechnology in harnessing the antimicrobial properties of natural essential oils, paving the way for innovative and sustainable solutions in the fight against bacterial contamination.

Recently, with the increase in diseases caused by bacterial and viral infections, the need for antibacterial agents has widely increased. On the other hand, with the development of drug resistance to organic groups of antibiotics, new antibiotics have attracted the attention of researchers because new methods are needed to reduce the activity of bacteria. Nanotechnology is increasingly being used for medical applications and is useful as an approach to kill or reduce the activity of various microorganisms. Metal oxides are considered for medical applications, especially as antibacterial agents, due to their potential advantages and suitable nanoscale properties. In this study, the electric discharge method was employed for the preparation of the iron oxide nanoparticles (IONPs) and iron-zinc oxide nanoparticles (IZONPs). As the IONPs and zinc oxide nanoparticles (ZONPs) attack various gram-positive and gram-negative bacteria by different mechanisms, it seems that the simultaneous use of these oxides can effectively kill various bacteria in outdoor and indoor media. The synthesized nanoparticles were characterized via XRD, UV-Visible, FE-SEM, EDS, HR-TEM, and TEM techniques. The obtained results showed that the IZONPs with mean particles size between 11 and 33 nanometers have successfully been synthesized in various experimental conditions. Also, the antibacterial properties of these nanoparticles were evaluated and the particles showed antibacterial properties against both gram-positive and gram-negative bacteria. [ABSTRACT FROM AUTHOR]

Fe S clusters are prosthetic groups present in all organisms. Proteins with Fe S centers are involved in most cellular processes. ISC and SUF are machineries necessary for the formation and insertion of Fe S in proteins. Recently, a phylogenetic analysis on more than 10,000 genomes of prokaryotes have uncovered two new systems, MIS and SMS, which were proposed to be ancestral to ISC and SUF. SMS is composed of SmsBC, two homologs of SufBC(D), the scaffolding complex of SUF. In this review, we will specifically focus on the current knowledge of the SUF system and on the new perspectives given by the recent discovery of its ancestor, the SMS system. • SufS and SufU sulfurtransferase for SufS sulfur transfer • SufU as zinc-containing protein • The two cofactors (Flavin and Fe-S) of SufBCD scaffold. • SmsCB is the scaffold of the ancestral system • Unknown sulfur donor for SMS system [ABSTRACT FROM AUTHOR]

Abstract Contamination of water with bacteria is one of the main causes of waterborne diseases. The photocatalytic method on the basis of bacterial inactivation seems to be a suitable disinfectant due to the lack of by-products formation. Herein, g-C3N4/Fe3O4/Ag nanocomposite combined with UV-light irradiation was applied for the inactivation two well-known bacteria namely, E. coli and B. subtilis. The nanocomposite was prepared by a hydrothermal method, and subsequently it was characterized by XRD, FT-IR, SEM, EDX and PL analyses. The optimum conditions established for the inactivation of both bacteria were as follows: nanocomposite dosage 3 g/L and bacterial density of 103 CFU/mL. In the meantime, the efficient inactivation of E. coli and B. subtilis took 30 and 150 min, respectively. The results also revealed that inactivation rate dropped with an increase in the bacterial density. It is also pointed out that OH˚ was found out to be the main radical species involved in the inactivation process. Finally, the kinetic results indicated that the inactivation of E. coli and B. subtilis followed the Weibull model. It is concluded that C3N4/Fe3O4/Ag nanocomposite along with UV-light irradiation is highly effective in inactivating E. coli and B. subtilis bacteria in the aqueous solutions.

[Display omitted] • Fe 3 O 4 @UiO-66-NH 2 @PEI was designed for broad-spectrum enrichment of bacteria. • Dual-mode sensing platform was constructed for sensitive and accurate detection of bacteria. • The platform achieved detection in real-sample with satisfactory results. • The sensor of Fe 3 O 4 @UiO-66-NH 2 @PEI exhibited excellent storage stability. Bacteria-induced food pollution poses a serious threat to human health. To detect early and sensitive traces of bacteria in food, a poly (ethyleneimine) (PEI)-modified magnetic organic framework material (Fe 3 O 4 @UiO-66-NH 2 @PEI) was prepared for broad-spectrum enrichment and dual-mode detection of typical gram-positive bacteria (Bacillus subtilis, B. subtilis) and gram-negative bacteria (Escherichia coli, E. coli) using Schiff's base reaction. Due to the positive charge caused by the abundance of amino groups, Fe 3 O 4 @UiO-66-NH 2 @PEI exhibited rapid enrichment of E. coli and B. subtilis within 12 min through the electrostatic interaction with bacteria. The biosensor based on Fe 3 O 4 @UiO-66-NH 2 @PEI achieved sensitive detection of E. coli and B. subtilis using the adenosine triphosphate (ATP) bioluminescence technology within the detection range of 101-107, and the detection limits were 44 and 57 CFU/mL, respectively under optimal experimental conditions. Moreover, a fluorescence platform was constructed by Fe 3 O 4 @UiO-66-NH 2 @PEI to achieve more diversified detection and reliable detection results for E. coli and B. subtilis. Within the detection range of 101-107, Fe 3 O 4 @UiO-66-NH 2 @PEI exhibited satisfactory linearity with detection limits of 6 CFU/mL and 14 CFU/mL. This biosensor using ATP bioluminescence and fluorescence technology showed remarkable recoveries (85.3–108.5 %) for E. coli and B. subtilis in biscuit matrices, indicating a bright prospect of the dual-mode platform for bacteria detection in food. [ABSTRACT FROM AUTHOR]

Contamination of water with bacteria is one of the main causes of waterborne diseases. The photocatalytic method on the basis of bacterial inactivation seems to be a suitable disinfectant due to the lack of by-products formation. Herein, g-C3N4/Fe3O4/Ag nanocomposite combined with UV-light irradiation was applied for the inactivation two well-known bacteria namely, E. coli and B. subtilis. The nanocomposite was prepared by a hydrothermal method, and subsequently it was characterized by XRD, FT-IR, SEM, EDX and PL analyses. The optimum conditions established for the inactivation of both bacteria were as follows: nanocomposite dosage 3 g/L and bacterial density of 103 CFU/mL. In the meantime, the efficient inactivation of E. coli and B. subtilis took 30 and 150 min, respectively. The results also revealed that inactivation rate dropped with an increase in the bacterial density. It is also pointed out that OH˚ was found out to be the main radical species involved in the inactivation process. Finally, the kinetic results indicated that the inactivation of E. coli and B. subtilis followed the Weibull model. It is concluded that C3N4/Fe3O4/Ag nanocomposite along with UV-light irradiation is highly effective in inactivating E. coli and B. subtilis bacteria in the aqueous solutions. [ABSTRACT FROM AUTHOR]

In the present study, the effect of B. subtilis (107cfu/gm) supplemented to the basal diet of two groups of New Zealand rabbit of 28 days (n=15/group) on the count of commensal microflora ( Bifidobacteria and Lactobacilli spp.) and some opportunistic pathogens (E. coli and C. perfringens type A) in the rabbit caeci was investigated. Results indicated that the count of Bifidobacteria and Lactobacilli spp. are significantly increased at all intervals (7, 14, 28 and 40 days post supplementation) in the supplemented group compared with non-supplemented group with P< 0.001. On the other hand, there is a significant decrease in the count of E. coli and C. perfringens specially at 40 days post supplementation from (5.8 log 10 cfu ±0.06) to (3.1 log 10 cfu ±0.07) and from (4.8 log 10 cfu ±0.09) to (2.3 log 10 cfu ±0.09) respectively with P< 0.001. B. subtilis proved to be tolerant to the simulated gastric and intestinal juice for one hour (100% tolerance). However, after two hours, the tolerance to the gastric juice decreased to 70%, with no effect of the artificial intestinal juice on the viability of the organism. In vitro, the antimicrobial effect of B. subtilis on C. perfringens type A by well diffusion method showed an inhibition zone of 10 mm. Results of in vitro effect of B. subtilis on C. perfringens count showed that at 103 dilutions of C. perfringens, its count was reduced 2.1×105 to 3×104 after adding B. subtilis, while at dilution of 102, the count was reduced from 2.4×105 to 7×103cfu/ml after adding B. subtilis. It could be concluded that B. subtilis can be used as a probiotic in rabbits ration due to its ability to increase the commensal microflora count beside its antibacterial effect against some opportunistic pathogens.

Sustainable biofuel production from renewable biomass will require the efficient and complete use of all abundant sugars in the plant cell wall. Using the cellulolytic fungus Neurospora crassa as a model, we identified a xylodextrin transport and consumption pathway required for its growth on hemicellulose. Reconstitution of this xylodextrin utilization pathway in Saccharomyces cerevisiae revealed that fungal xylose reductases act as xylodextrin reductases, producing xylosyl-xylitol oligomers as metabolic intermediates. These xylosyl-xylitol intermediates are generated by diverse fungi and bacteria, indicating that xylodextrin reduction is widespread in nature. Xylodextrins and xylosyl-xylitol oligomers are then hydrolyzed by two hydrolases to generate intracellular xylose and xylitol. Xylodextrin consumption using a xylodextrin transporter, xylodextrin reductases and tandem intracellular hydrolases in cofermentations with sucrose and glucose greatly expands the capacity of yeast to use plant cell wall-derived sugars and has the potential to increase the efficiency of both first-generation and next-generation biofuel production.

Treating the biological waste used in bacterial culture is so important to save the environment and this can be useful for laboratories in countries with limited resources, which means financial benefit. The investigation of the bacterial growth on the used media recycled was studied in this work. The general media (plate count agar) can be reused twice after the recycling to cultivate and identify E. coli, S. aureus, Salmonella sp, and B. subtilis by the spread method on the plate count agar medium. The size of bacterial colonies decreased in the second step of the recycling from -30 to -60% in comparison with the control. The processes to recycle the used media help transform it to new powder that could be stored for a long time (up to six months). Three methods of additional sterilization were tested on the used media: (1) the sterilization by gamma irradiation at 5 kGy, (2) the microwave for 8 min, and (3) the hot drying in oven at 80 °C. Using the microwave radiation during the processes of recycling allowed having new media, with color and clarity similar of the fresh media and available in laboratories. [ABSTRACT FROM AUTHOR]

Eucheuma spinosum, red algae, contains secondary metabolites that act as antibacterial. It can be used as an active compound in the production of alcohol-free hand sanitizer. This research was aimed to determine the gram-positive and gram-negative antibacterial activity, pH, and viscosity of alcohol-free hand sanitizer containing E. spinosum extract. The results showed that the alcohol-free hand sanitizer containing 8% E. spinosum extract had characteristics in the form of a gel with the antibacterial activity of gram-positive bacteria (Bacillus subtilis) of 8.83±0.76 mm and gram-negative bacteria (Escherichia coli) of 8.67±0.58 mm, pH appropriate to pH of skin human (5.83±0.29), and viscosity following the hand sanitizer standard (2708 cps). [ABSTRACT FROM AUTHOR]

ZnO nanoparticles were successfully synthesized using a microwave method, whose surface was modified with {4‐[(E)‐2‐(furan‐2‐yl)ethenyl]pyridin‐1‐ium‐1‐yl}acetate as a capping agent (1 and 3%). Their structural properties were investigated using FTIR, XRD, SEM, EDS, and UV–visible spectroscopy. XRD confirmed the Wurtzite structure for all compounds, a size of 30.6 nm for uncapped and 22.9 nm for 3% dye‐capped nanoparticles were calculated from Scherer's equation. Hexagonal wurtzite shape of nanoparticles can be clearly seen in the SEM images. The DFT calculations were carried out using quantum espresso. These dye‐capped ZnO nanoparticles were proved to be potential antibacterial agents, the minimum concentrations of dye‐capped ZnO nanoparticles that inhibit the growth of bacteria are 1.5 mg/mL for Escherichia coli and 0.78 mg/mL for Bacillus subtilis, which are much lower than those of uncapped ZnO. The bioactivity data suggest these organic–inorganic hybrid nanoparticles emerged as a new class of antibacterial agents. [ABSTRACT FROM AUTHOR]

The purpose of the study was to synthesize potent antimicrobial and cytotoxic agents by condensing sulphanilamide with 1,2,3,4-tetrahydropyrimidines. A new series of novel sulphanilamide condensed 1,2,3,4-tetrahydropyrimidines was prepared by reacting N-[(4-aminophenyl) sulphonyl]-3-oxobutanamide with urea/thiourea and aryl aldehyde in the presence of a catalytic amount of laboratory prepared chlorosulphonic acid as an efficient catalyst. The chemical structures of the synthesized compounds (7a-r) were confirmed by TLC, and the compounds were characterized by IR, 1H NMR, mass spectra and elemental analysis. The synthesized compounds were evaluated for antimicrobial activity against the Gram-positive bacteria Bacillus subtilis and the Gram-negative bacteria Escherichia coli and for cytotoxicity against Vero cells. These compounds exhibited weak, moderate, or high antimicrobial activities and cytotoxicity. In particular, compound 7p exhibited the best antimicrobial activity and cytotoxicity of all the 1,2,3,4-tetrahydropyrimidine derivatives with antimicrobial activity MIC values of 11.4 μM and 12.1 μM against B. subtilis and E. coli, respectively, and a cytotoxicity CTC50 value of 19.0 μM against Vero cells. The sulphanilamide condensed 1,2,3,4-tetrahydropyrimidines generated here might prove interesting as potential antimicrobial cytotoxic agents.

The increasing detection of virulent and/or multidrug resistant bacterial strains makes necessary the development of new antimicrobial agents acting through novel mechanisms and cellular targets. A good choice are molecules aimed to interfere with the cell division machinery or divisome, which is indispensable for bacterial survival and propagation. A key component of this machinery, and thus a good target, is FtsZ, a highly conserved GTPase protein that polymerizes in the middle of the cell on the inner face of the cytoplasmic membrane forming the Z ring, which acts as a scaffold for the recruitment of the divisome proteins at the division site. In this work, we tested the inhibitory effect of five diaryl naphtyl ketone (dNAK) molecules on the in vitro polymerization of both Escherichia coli and Bacillus subtilis FtsZ (EcFtsZ and BsFtsZ, respectively). Among these compounds, dNAK 4 showed the strongest inhibition of FtsZ polymerization in vitro, with an IC50 of 2.3 ± 0.06 μM for EcFtsZ and 9.13 ± 0.66 μM for BsFtsZ. We found that dNAK 4 binds to GDP-FtsZ polymers but not to the monomer in GTP or GDP state. This led to the polymerization of short and curved filaments, rings, open rings forming clusters, and in the case of BsFtsZ, a novel cylindrical structure of stacked open rings. In vivo, dNAK 4 had almost no effect on the growth of E. coli in liquid culture, in contrast to the strong inhibitory effect observed over B. subtilis growth. The insensitivity of E. coli to this compound is probably related to the impermeability of dNAK 4 to the outer membrane. The low amount of this compound required to inhibit several of the bacterial strains tested and the lack of a cytotoxic effect at the concentrations used, makes dNAK 4 a very good candidate as a starting molecule for the development of a new antibiotic.

The increasing detection of virulent and/or multidrug resistant bacterial strains makes necessary the development of new antimicrobial agents acting through novel mechanisms and cellular targets. A good choice are molecules aimed to interfere with the cell division machinery or divisome , which is indispensable for bacterial survival and propagation. A key component of this machinery, and thus a good target, is FtsZ, a highly conserved GTPase protein that polymerizes in the middle of the cell on the inner face of the cytoplasmic membrane forming the Z ring, which acts as a scaffold for the recruitment of the divisome proteins at the division site. In this work, we tested the inhibitory effect of five diaryl naphtyl ketone (dNAK) molecules on the in vitro polymerization of both Escherichia coli and Bacillus subtilis FtsZ (EcFtsZ and BsFtsZ, respectively). Among these compounds, dNAK 4 showed the strongest inhibition of FtsZ polymerization in vitro , with an IC50 of 2.3 ± 0.06 μM for EcFtsZ and 9.13 ± 0.66 μM for BsFtsZ. We found that dNAK 4 binds to GDP-FtsZ polymers but not to the monomer in GTP or GDP state. This led to the polymerization of short and curved filaments, rings, open rings forming clusters, and in the case of BsFtsZ, a novel cylindrical structure of stacked open rings. In vivo , dNAK 4 had almost no effect on the growth of E. coli in liquid culture, in contrast to the strong inhibitory effect observed over B. subtilis growth. The insensitivity of E. coli to this compound is probably related to the impermeability of dNAK 4 to the outer membrane. The low amount of this compound required to inhibit several of the bacterial strains tested and the lack of a cytotoxic effect at the concentrations used, makes dNAK 4 a very good candidate as a starting molecule for the development of a new antibiotic. [ABSTRACT FROM AUTHOR]

Pathogenic infectious diseases, like bacterial infections, are one of the most prevalent types of diseases all over the world. Although antibiotics are commonly used and widely available drugs for the treatment of bacterial infections, bacteria show multiple drug resistance, have a tendency to get genetically mutated and become resistant to commonly employed antibiotic drugs. This makes the invention of novel drugs essential. One of the possible approaches is the use of nanomaterials for this purpose. The present study attempts to synthesize silver nanospheres and silver nanowires and compare their antibacterial activity. Silver nanospheres were synthesized by chemical reduction of silver nitrate in the presence of a suitable stabilizer. For the synthesis of silver nanowires, polyol method was employed. Silver nanowires neatly decorated with silver nanospheres were obtained. The antibacterial activity was estimated by separately determining the minimum inhibition concentration of the two nanostructures on Gram-positive bacteria Bacillus subtilis and Gram-negative bacteria Escherichia coli cultured on Luria Bertani agar media. The comparison shows that the antibacterial activity of silver nanospheres is better than that of silver nanowires which is attributed to its higher surface area and the difference in uptake mechanism by the bacterial cells. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Vancomycin-modified gold nanoparticles were synthesized by a one-pot reaction. • A colorimetric and test stripe-based assay was established for Gram-positive bacteria. • This assay is rapid and easy, and does not require the use of any microscopic devices. • Six species of Gram-positive and Gram-negative bacteria were tested. Abstract Bacteria are the most principal pathogens threatening human health. Rapid, simple, and sensitive identification and assay for bacteria are greatly desired for clinical diagnosis and environmental monitoring. In this work, a commonly used antibiotic vancomycin (Van) was used to synthesize gold nanoparticles (Au NPs) by a simple one-pot reaction, and the resultant Van-coated Au NPs (denoted as Van-AuNPs) can selectively interact with Gram-positive bacteria and thus be used to differentiate Gram-positive bacteria from Gram-negative ones through the change of their red color. On this basis, Van-AuNPs-based visual colorimetric assay was established for Gram-positive bacteria. The detection limits of bare eyes for Gram-positive S. aureus , M. luteus, and B. subtilis are 1 × 109, 1 × 109, and 1 × 109 cells/mL, respectively, according to the color of the spots on the test strip without the use of any microscopic devices. We also used this method to detect S. aureus in orange juice and tap water with excellent recoveries. Compared with conventional bacterial identification methods, this assay is rapid and easy, and is promising to be used as a rapid method for the identification and quantification of bacteria in clinics, environment, and fieldwork. [ABSTRACT FROM AUTHOR]

High-throughput molecular studies are greatly advancing our knowledge of the human microbiome and its specific role in governing health and disease states. A myriad of ongoing studies aim at identifying links between microbial community disequilibria (dysbiosis) and human diseases. However, due to the inherent complexity and heterogeneity of the human microbiome we need robust experimental models that allow the systematic manipulation of variables to test the multitude of hypotheses arisen from large-scale ‘meta-omic’ projects. The nematode C. elegans combined with bacterial models offers an avenue to dissect cause and effect in host-microbiome interactions. This combined model allows the genetic manipulation of both host and microbial genetics and the use of a variety of tools, to identify pathways affecting host health. A number of recent high impact studies have used C. elegans to identify microbial pathways affecting ageing and longevity, demonstrating the power of the combined C. elegans-bacterial model. Here I will review the current state of the field, what we have learned from using C. elegans to study gut microbiome and host interactions, and the potential of using this model system in the future. [ABSTRACT FROM AUTHOR]

A new series of some novel isoniazid condensed 1,4-dihydropyridines was prepared by reaction of N-(3-oxobutanoyl) isonicotinohydrazide with aryl aldehyde and 25–30% ammonia solution in the presence of catalytic amount of barium nitrate as an efficient catalyst. The confirmation of the chemical structure of the synthesized compounds (4a–m) was substantiated by TLC, different spectral data IR, 1H NMR, 13C NMR, and mass spectra and elemental analysis was done. The synthesized compounds were evaluated for antimicrobial activity and cytotoxicity against Gram-positive bacteria Bacillus subtilis, Gram-negative bacteria Escherichia coli and Vero cells. All the reported compounds exhibited weak, moderate, or high antimicrobial activity and cytotoxicity. Especially, compound 4i showed the best antimicrobial activity and cytotoxicity of all the 1,4-dihydropyridine derivatives, with an MIC value of 11.5 μM, 12.2 μM and a CTC50 value of 27 μM.

Nisin is a known bacteriocin, which exhibits a wide spectrum of antimicrobial activity, while commonly being inefficient against Gram-negative bacteria. In this work, we present a proof of concept of novel antimicrobial methodology using targeted magnetic nisin-loaded nano-carriers [iron oxide nanoparticles (NPs) (11–13 nm) capped with citric, ascorbic, and gallic acids], which are activated by high pulsed electric and electromagnetic fields allowing to overcome the nisin-resistance of bacteria. As a cell model the Gram-positive bacteria Bacillus subtilis and Gram-negative Escherichia coli were used. We have applied 10 and 30 kV cm-1 electric field pulses (100 μs × 8) separately and in combination with two pulsed magnetic field protocols: (1) high dB/dt 3.3 T × 50 and (2) 10 mT, 100 kHz, 2 min protocol to induce additional permeabilization and local magnetic hyperthermia. We have shown that the high dB/dt pulsed magnetic fields increase the antimicrobial efficiency of nisin NPs similar to electroporation or magnetic hyperthermia methods and a synergistic treatment is also possible. The results of our work are promising for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections.

The purpose of the study was to synthesize potent antimicrobial and cytotoxic agents by condensing sulphanilamide with 1,2,3,4-tetrahydropyrimidines. A new series of novel sulphanilamide condensed 1,2,3,4-tetrahydropyrimidines was prepared by reacting N -[(4-aminophenyl) sulphonyl]-3-oxobutanamide with urea/thiourea and aryl aldehyde in the presence of a catalytic amount of laboratory prepared chlorosulphonic acid as an efficient catalyst. The chemical structures of the synthesized compounds (7a-r) were confirmed by TLC, and the compounds were characterized by IR, 1 H NMR, mass spectra and elemental analysis. The synthesized compounds were evaluated for antimicrobial activity against the Gram-positive bacteria Bacillus subtilis and the Gram-negative bacteria Escherichia coli and for cytotoxicity against Vero cells. These compounds exhibited weak, moderate, or high antimicrobial activities and cytotoxicity. In particular, compound 7p exhibited the best antimicrobial activity and cytotoxicity of all the 1,2,3,4-tetrahydropyrimidine derivatives with antimicrobial activity MIC values of 11.4 μM and 12.1 μM against B. subtilis and E. coli , respectively, and a cytotoxicity CTC 50 value of 19.0 μM against Vero cells . The sulphanilamide condensed 1,2,3,4-tetrahydropyrimidines generated here might prove interesting as potential antimicrobial cytotoxic agents. [ABSTRACT FROM AUTHOR]

Aqueous silver nanocolloid was synthesized in a single step by a biogenic approach using aqueous leaf extract of Lippia javanica plant which acts as both reducing as well as capping agent. The as-synthesized silver nanoparticles were characterized by UV-visible absorption spectroscopy, high-resolution transmission electron microscopy and Fourier transform infrared spectroscopy (FTIR). The UV-Vis absorption spectra of colloidal silver nanoparticles showed characteristic surface plasmon resonance peak centered at a wavelength of 415 nm. The kinetic study showed that the reduction process was complete within 2 h of time. The TEM analysis showed that most of the particles were spherical in shape and their average diameter was about 17.5 nm. FTIR study confirmed the presence of some organic functional groups in leaf extract and their participation during the reduction as well as stabilization process. In addition, the as-synthesized silver nanoparticles showed antimicrobial activity against clinically isolated pathogenic strain of E. coli and B. subtilis. [ABSTRACT FROM AUTHOR]

Effluent from textile industries contain various azo dyes. Methylene Blue is one of the most predominant one which is hazardous for the environment and has to be degraded chemically or biochemically. A pure culture ofBacillus subtilisandE. colicells which were already acclimatized to phenol as the sole carbon source were taken for the purpose of the present work. The rate of degradation of MB forE. colihad increased at a much slower rate than that ofB. subtilisover the entire degradation period. Hence, in the batch process, overall removal efficiency of Methylene Blue byB. subtilisis higher than that ofE. coli. Thus,B. subtiliswas taken for further biodegradation of Methylene Blue studies in a continuous process in a counter current packed bed reactor packed with clay chips. In addition to a packing material, the clay chips also act as a whole cell immobilizing matrix for theBacilluscells. The effect of Methylene Blue flow rate and air flow rate on percentage Methylene Blue removal efficiency was observed. The optimum air flow rate and substrate flow rate for maximum removal efficiency of Methylene Blue were 2.0 lpm and 0.5 mL/min, respectively. Maximum removal efficiency under these conditions was 84.7%. [ABSTRACT FROM AUTHOR]

Hydraphiles are synthetic amphiphiles that form ion-conducting pores in liposomal membranes. These pores exhibit open-close behavior when studied by planar bilayer conductance techniques. In previous work, we showed that when co-administered with various antibiotics to the DH5α strain of Escherichia coli , they enhanced the drug’s potency. We report here potency enhancements at low concentrations of hydraphiles for the structurally and mechanistically unrelated antibiotics erythromycin, kanamycin, rifampicin, and tetracycline against Gram negative E. coli (DH5α and K-12) and Pseudomonas aeruginosa , as well as Gram positive Bacillus subtilis . Earlier work suggested that potency increases correlated to ion transport function. The data presented here comport with the function of hydraphiles to enhance membrane permeability in addition to, or instead of, their known function as ion conductors. [ABSTRACT FROM AUTHOR]

A new series of some novel isoniazid condensed 1,4-dihydropyridines was prepared by reaction of N-(3-oxobutanoyl) isonicotinohydrazide with aryl aldehyde and 25–30% ammonia solution in the presence of catalytic amount of barium nitrate as an efficient catalyst. The confirmation of the chemical structure of the synthesized compounds (4a–m) was substantiated by TLC, different spectral data IR, 1 H NMR, 13 C NMR, and mass spectra and elemental analysis was done. The synthesized compounds were evaluated for antimicrobial activity and cytotoxicity against Gram-positive bacteria Bacillus subtilis , Gram-negative bacteria Escherichia coli and Vero cells . All the reported compounds exhibited weak, moderate, or high antimicrobial activity and cytotoxicity. Especially, compound 4i showed the best antimicrobial activity and cytotoxicity of all the 1,4-dihydropyridine derivatives, with an MIC value of 11.5 μM, 12.2 μM and a CTC 50 value of 27 μM. [ABSTRACT FROM AUTHOR]

To better understand the potential impacts of metal oxide nanoparticles (NPs) on Gram(+) Bacillus subtilis and Gram(−) Escherichia coli (K12) bacteria, eight different nanosized titanium dioxide (TiO) suspensions with five different concentrations were used. Water quality parameters (pH, temperature, and ionic strength), light sources, and light intensities were also changed to achieve different environmental conditions. The photosensitive TiO NPs were found to be harmful to varying degrees under ambient conditions, with antibacterial activity increasing with primary particle sizes from 16 to 20 nm. The presence of light was a significant factor under most conditions tested, presumably due to its role in promoting generation of reactive oxygen species (ROS). However, bacterial growth inhibition was also observed under dark conditions and different water quality parameters, indicating that undetermined mechanisms additional to photocatalytic ROS production were responsible for toxicity. The results also indicated that nano-TiO particles in the absence and the presence of photoactivation induced lipid peroxidation and cellular respiration disruption. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to obtain insights into how bacterial adhesion to soils affect the surface charges of soil Fe/Al hydroxides. Materials and methods: Adhesion of Escherichia coli and Bacillus subtilis by amorphous Fe and Al hydroxides was investigated using a batch method. Zeta potential measurements and potentiometric titrations were used to study the effects of bacteria adhesion on the surface charges of Fe and Al hydroxides. Results and discussion: The amorphous Al(OH) adhesion capacity of the two bacteria species was greater than that of amorphous Fe(OH) due to the much larger positive charge on amorphous Al(OH) compared to amorphous Fe(OH). The maximum Al(OH) adhesion capacities, obtained by fitting a Langmuir equation, were 2,689.6 and 2,358.7 g/kg for E. coli and B. subtilis, respectively, and the maximum Fe(OH) adhesion capacities of the two bacteria were 750.5 and 893.6 g/kg, respectively. Adhesion of both E. coli and B. subtilis to amorphous Fe and Al hydroxides decreased with increasing pH at pH < their points of zero charge (PZC), which was consistent with the change in interaction energy, as calculated by the classical DLVO theory, between the bacteria and the Fe/Al hydroxides. The electrostatic force plays an important role in bacterial adhesion by the Fe and Al hydroxides. The FTIR spectra revealed that chemical bond formation also contributed to the interactions between the bacteria and amorphous Fe and Al hydroxides. E. coli and B. subtilis adhesion decreased the positive charges and zeta potentials of the Fe and Al hydroxides, and shifted the PZCs of the Fe and Al hydroxides to lower pH. The larger number of negative charge on B. subtilis meant that it had a greater effect on the surface charge properties of the Fe and Al hydroxides compared to E. coli. Conclusions: Electrostatic force plays an important role in E. coli and B. subtilis adhesion to amorphous Fe and Al hydroxides. Bacterial adhesion led to the decreases in positive charges and PZCs of the hydroxides. [ABSTRACT FROM AUTHOR]

Disinfection of municipal wastewater effluents is a critical component of water pollution control. To achieve this, novel alternative disinfection technologies have been getting attention recently such as pulsed ultraviolet (UV) light, which can be used to inactivate microorganisms in a short time. Therefore, the research reported in this paper was undertaken to determine the efficacy of pulsed UV light for inactivation of Escherichia coli and Bacillus subtilis spores, in synthetic and real municipal wastewater effluent. The results with synthetic municipal wastewater effluent demonstrated that complete inactivation was obtained with an 8-cm sample distance, 30-mL sample volume, and 15-s time combination for E. coli [8.53log10 colony-forming units (CFUs)/mL reduction], whereas a 15-mL sample volume (with the same sample distance and treatment time) was required for B. subtilis (7.57log10(CFUs)/mL reduction) at total energy dose of 10.9 J=cm². A response surface model was developed to predict the inactivation for E. coli and B. subtilis spores. Using sterilized real wastewater effluent with the same experimental conditions of an 8-cm distance and 30-mL volume for E. coli, and 8-cm distance and 15-mL volume for B. subtilis, complete inactivation required the same 15-s treatment for E. coli, but 20-s treatment for B. subtilis. In addition, a 2.5, 5, 10, 15, and 25% (volume=volume) E. coli or B. subtilis inoculum was added to the synthetic municipal wastewater effluent, and treated by pulsed UVlight for 5-45 s. Results showed that pulsed UV treatment at the optimum conditions increased suspended solids removal by 26.5 and 21.45%, for E. coli and B. subtilis, respectively. Overall, the results of the research reported in this paper clearly demonstrated the complete inactivation of vegetative cells or spores in municipal wastewater effluents, and further demonstrated the reduction of suspended solids, suggesting that pulsed UV light has the potential to be used for disinfection of municipal wastewater effluent. [ABSTRACT FROM AUTHOR]

One-electron oxidation of acetohydroxamic acid (aceto-HX) initially gives rise to nitroxyl (HNO), which can be further oxidized to nitric oxide (NO) or react with potential biological targets such as thiols and metallo-proteins. The distinction between the effects of NO and HNO in vivo is masked by the reversible redox exchange between the two congeners and by the Janus-faced behavior of NO and HNO. The present study examines the ability of aceto-HX to serve as an HNO donor or an NO donor when added to Escherichia coli and Bacillus subtilis subjected to oxidative stress by comparing its effects to those of NO and commonly used NO and HNO donors. The results demonstrate that: (i) the effects of NO and HNO on the viability of prokaryotes exposed to H 2 O 2 depend on the type of the bacterial cell; (ii) NO synergistically enhances H 2 O 2 -induced killing of E. coli, but protects B. subtilis depending on the extent of cell killing by H 2 O 2 ; (iii) the HNO donor Angeli׳s salt alone has no effect on the viability of the cells; (iv) Angeli׳s salt synergistically enhances H 2 O 2 -induced killing of B. subtilis , but not of E. coli ; (v) aceto-HX alone (1–4 mM) has no effect on the viability of the cells; (vi) aceto-HX enhances the killing of both cells induced by H 2 O 2 and metmyoglobin, which may be attributed in the case of B. subtilis to the formation of HNO and to further oxidation of HNO to NO in the case of E. coli ; (vii) the synergistic activity of aceto-HX on the killing of both cells induced by H 2 O 2 alone does not involve reactive nitrogen species. The effect of aceto-HX on prokaryotes under oxidative stress is opposite to that of other hydroxamic acids on mammalian cells. [ABSTRACT FROM AUTHOR]

Effect directed analysis method is proposed for searching compounds with antibacterial and radical scavenging properties in herbs. The method is based on thin-layer chromatography–direct bioautography of plant extracts and chemical screening using derivatization reagents.Bacillus subtilisandEscherichia coliwere used as test bacteria for searching antibacterial properties of plant constituents and DPPH as a reagent for testing radical scavenging properties directly on earlier developed TLC plates. Anisaldehyde-sulfuric acid and natural product/polyethylene glycol 4000 reagent were used for derivatization of terpenoids and polyphenols, respectively. [ABSTRACT FROM AUTHOR]

Several triphenyltin chloride picoline N-oxide adducts were synthesized. X-ray studies of triphenyltin chloride 4-picoline N-oxide indicate that the adduct has a distorted trigonal bipyramid (TBP) configuration with the phenyl groups in the equatorial positions and the axial positions being occupied by the 4-picoline N-oxide ligand and chlorine atom. Structures of the other adducts are assumed to be similar based on the IR spectra. Multinuclear NMR studies indicated that the TBP configuration is lost in solution. Screening results of the adducts against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) indicate that the E. coli were more tolerant to the adducts. In addition to the adducts, three other series of triorganotins that incorporated various modified fragments of pyrethroids were also tested against B. subtilis and E. coli. No common order of toxicity was observed for these compounds based on the organic group attached to the tin atom. In addition to the evaluation of the triphenyltin chloride adducts and modified triorganotins against the two bacteria, 12 commercial triorganotins were evaluated against a freshwater snail, Biomphalaria glabrata (B. glabrata). The screening results indicated that the bacteria are more tolerant to the triorganotins than B. glabrata. [ABSTRACT FROM AUTHOR]

It is known that antibiotics cause allergies in some people as well as their overdoses inducing kidney and liver failure. They may also cause side effects such as glossitis, stomatitis, nausea, vomiting, pseudomembranous colitis, diarrhea, skin erythema, and dermatitis. In this study, possible antibacterial effects of electromagnetic waves were investigated to find an alternative solution to antibiotics. To investigate antibacterial effects of electromagnetic waves, E. coli and B. subtilis were considered as example organisms. As a result of performed experimental studies, it was shown that electromagnetic waves suppress the growth of microorganisms. [ABSTRACT FROM AUTHOR]

Abstract: This study examined antioxidant and antimicrobial activities of medium oat bran treated with four polysaccharide enzymes viscozyme, cellulase, alpha-amylase, and amyloglucosidase. The effects of these enzymes on the release of phenolic acids were determined using reverse-phase HPLC chromatography. Antioxidant assays showed that enzyme pre-treatments significantly increased the hydroxyl radical (HO ) scavenging activity of all bran samples (16.6–20.0μM propyl gallate equivalents (PGE)/g bran) relative to untreated bran (13.3±1.8μM PGE/g). The order of activity was cellulase≈viscozyme>amyloglucosidase≈alpha-amylase. The DPPH free radical inhibitory activities of brans pre-treated with cellulase and amyloglucosidase, 43.0% and 45.0%, respectively were higher than inhibition by untreated bran 21.7% (P<0.05). In the linoleic acid (LA) autoxidation assay, three of the treated and untreated brans similarly inhibited LA oxidation, while viscozyme pre-treated bran had no activity. HPLC analysis showed an increase in free phenolic acids, and this was more pronounced for ferulic and caffeic acids. In the antimicrobial assay, brans pre-treated with viscozyme and cellulase similarly inhibited the growth of Escherichia coli compared to untreated bran (P<0.05), while viscozyme- and alpha-amylase-treated brans enhanced the growth of Bacillus subtilis, a non-pathogenic bacteria strain that has been used as a pro-biotic. [Copyright &y& Elsevier]