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Cross-linked polymers synthesized through inverse vulcanization of unsaturated vegetable oils (biopolymers) were used as matrices for incorporating gentamicin (GEN) to form a biocomposite that can amplify GEN antimicrobial activity against Pseudomonas aeruginosa. Two different biopolymers were synthesized using soybean (PSB) and sunflower (PSF) oils by inverse vulcanization cross-linked with sulfur in a 1:1 weight ratio. The study involves the synthesis and characterization of these biopolymers using FTIR and SEM as well as measurements of density and hydrophobicity. The results reveal the formation of biopolymers, wherein triglyceride molecules undergo cross-linking with sulfur chains through a reaction with the unsaturated groups present in the oil. Additionally, both polymers exhibit a porous structure and display hydrophobic behavior (contact angle higher than 120°). The biopolymers swell more in GEN solution (PSB 127.7% and PSF 174.4%) than in pure water (PSB 88.7% and PSF 109.1%), likely due to hydrophobic interactions. The kinetics of GEN sorption and release within the biopolymer matrices were investigated. The antibacterial efficacy of the resulting biocomposite was observed through the analysis of inhibition growth halos and the assessment of P. aeruginosa viability. A notable enhancement of the growth inhibition halo of GEN (13.1 ± 1.1 mm) compared to encapsulated GEN (PSF-GEN 21.1 ± 1.3 and PSB-GEN 21.45 ± 1.0 mm) is observed. Also, significant bactericidal activity is observed in PSF-GEN and PSB-GEN as a reduction in the number of colonies (CFU/mL), more than 2 log10 compared to control, PSF, and PSB, highlighting the potential of these biopolymers as effective carriers for gentamicin in combating bacterial infections. [ABSTRACT FROM AUTHOR]

Cross-linked polymers synthesized through inverse vulcanization of unsaturated vegetable oils (biopolymers) were used as matrices for incorporating gentamicin (GEN) to form a biocomposite that can amplify GEN antimicrobial activity against Pseudomonas aeruginosa. Two different biopolymers were synthesized using soybean (PSB) and sunflower (PSF) oils by inverse vulcanization cross-linked with sulfur in a 1:1 weight ratio. The study involves the synthesis and characterization of these biopolymers using FTIR and SEM as well as measurements of density and hydrophobicity. The results reveal the formation of biopolymers, wherein triglyceride molecules undergo cross-linking with sulfur chains through a reaction with the unsaturated groups present in the oil. Additionally, both polymers exhibit a porous structure and display hydrophobic behavior (contact angle higher than 120°). The biopolymers swell more in GEN solution (PSB 127.7% and PSF 174.4%) than in pure water (PSB 88.7% and PSF 109.1%), likely due to hydrophobic interactions. The kinetics of GEN sorption and release within the biopolymer matrices were investigated. The antibacterial efficacy of the resulting biocomposite was observed through the analysis of inhibition growth halos and the assessment of P. aeruginosa viability. A notable enhancement of the growth inhibition halo of GEN (13.1 ± 1.1 mm) compared to encapsulated GEN (PSF-GEN 21.1 ± 1.3 and PSB-GEN 21.45 ± 1.0 mm) is observed. Also, significant bactericidal activity is observed in PSF-GEN and PSB-GEN as a reduction in the number of colonies (CFU/mL), more than 2 log10 compared to control, PSF, and PSB, highlighting the potential of these biopolymers as effective carriers for gentamicin in combating bacterial infections.

Bacterial diseases cause colossal losses in vegetable crops and are considered major limiting factors for the commercial production of vegetables around the globe. Among bacterial diseases, angular leaf spot of cucumber caused by Pseudomonas syringae is one of the most economically important diseases that cause substantial economic loss to the cucumber crop. In this study, the in‐vitro and in‐vivo effects of different strains (X1–X15) of the nematode symbiotic bacterium Xenorhabdus nematophila was determined on the growth of P. syringae in different selected media (TB, SB, SOB, SOC, YT and LB) and at different pH levels (6.5, 7.5 and 8.5) and on the incidence of angular leaf spot disease on potted cucumber plants. According to the results, maximum growth inhibition of P. syringe (25 mm) was observed in the case of strain X12, followed by strains X10 (23 mm), X8 (21 mm) and X6 (20 mm), while maximum colony growth was observed in the control. Moreover, this P. syringae growth inhibition by the X12 strain of X. nematophila was significantly maximum in SB medium and at pH 7.5. Results of the in‐vivo experiment with potted plants showed a maximum incidence (90%) of angular leaf spot disease in control plants, while a minimum disease incidence (15%) was observed for the plants treated with two times dilution of X. nematophila culture, followed by ten times (23%) and fifty times (35%). The overall results of this study demonstrate the inhibitory effect of X. nematophila on the growth and incidence of P. syringae and underscore its putative role in the biological management of plant pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Streptococcus mutans bacteria form a biofilm called plaque that causes oral diseases, including tooth decay. Therefore, inhibition of biofilm formation is essential to maintaining good oral health. The health and nutritional benefits of Cynodon dactylon are well documented, but very little is known about its use to treat against oral diseases. The aim of this study was to detect the adhesion strength of the S. mutans bacterial biofilm in 100 cases in the Rajshahi region and evaluate the inhibitory activity of different compound extracts of C. dactylon on the S. mutans bacterial biofilm by determining the composition of isolated compounds using phytochemical analysis. Nuclear magnetic resonance (NMR) spectroscopy confirmed that three specific compounds from C. dactylon were discovered in this study: 3,7,11,15 tetramethyl hexadec-2-4dien 1-o1, compound 3,7,11,15 tetramethylhexadec-2-en-1-o1 from phytol derivatives, and stigmasterol. Results indicated that the compound of 3,7,11,15-tetramethyl-hexadec-2-en-1-ol exhibited higher antibiofilm activities on S. mutans than those of the other compound extracts. A lower level of minimum inhibitory concentration was exposed by 3, 7, 11,15 tetramethyl hexadeca-2-en-1-o1 (T2) on S. mutans at 12.5 mL. In this case, the compound of 3,7,11,15 tetramethyl hexadec 2en-1-o1 was used, and patients showed a mean value and standard error reduced from 3.42 ± 0.21 to 0.33 ± 0.06 nm. The maximum inhibition was (80.10%) in the case of patient no. 17, with a value of p < 0.05 found for S. mutans to which 12.5 μL/mL ethyl acetate extract was applied. From these findings, it may be concluded that C. dactylon extracts can be incorporated into various oral preparations to prevent tooth decay. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) is a frequently encountered heavy metal contaminant in agricultural soil and water sources resulting from industrial and agricultural applications, traffic, and urbanization. It is the most toxic form of chromium (Cr), which causes severe health problems. The accumulation capacity of Swiss chard (Beta vulgaris L. var. cicla) for hexavalent chromium and the effect of heavy metal accumulation on the antibacterial activity of plant extracts were evaluated in a pot experiment. The soil was treated with 10 mg kg−1 hexavalent chromium, 30 days prior to planting Swiss chard seedlings. After the harvest, macro- and micronutrient elements and Cr were measured using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES). Moreover, plant extracts were obtained by maceration in methanol and the extracts were tested against Gram-positive and Gram-negative bacteria. Cr was found to be uptaken and accumulated with a high concentration (54.7 ± 0.23 mg kg−1) in the aerial parts (transfer factor = 74.95). Cr toxicity reduced plant development and the macronutrient elements phosphorus and potassium in Swiss chard. The micronutrient elements iron and boron were found to be significantly increased in plant upon chromium in a synergistic manner with Cr. Additionally, the antibacterial activity of the extract of Swiss chard decreased against Staphylococcus aureus and Enterococcus faecalis around 50%. Moreover, the number of culturable bacteria decreased about 40% in soil after chromium treatment. The results suggested that this plant can accumulate a high amount of Cr in its aerial parts, which may decrease the health effects of the extracts. [ABSTRACT FROM AUTHOR]

The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a non-toxic, natural, biologically active substance, such as fucoidan, to inhibit bacterial growth on similar medical coatings. The fucoidan amount was varied, and its impact on the bioadhesion-influencing surface characteristics, as well as on bacterial cell growth, was investigated. The inclusion of up to 3–4 wt.% brown algae-derived fucoidan in the coatings increases their inhibitory effect, more significantly on the Gram-positive bacterium S. aureus than on the Gram-negative bacterium Escherichia coli. The biological activity of the studied siloxane coatings was ascribed to the formation of a low-adhesive, biologically active surface top layer consisting of siloxane oil and dispersed water-soluble fucoidan particles. This is the first report on the antibacterial activity of fucoidan-containing medical siloxane coatings. The experimental results give reason to expect that relevantly selected, natural biologically active substances can be efficient in the non-toxic control of bacterial growth on medical devices and, as a result, medical device-associated infections. [ABSTRACT FROM AUTHOR]

• Continuous wear of Kinesio Tapes leads to accumulation of environmental microorganisms and opportunistic pathogens. • The organisms accumulated on Kinesio Tapes show varying degrees of antimicrobial resistance. • Kinesio Tapes can affect the growth of the human skin microbiota. Kinesio tapes (KTs) are tapes used in physical therapy and athletics. We sought to evaluate if wearing KTs for extended periods of time increases exposure to antibiotic resistant opportunistic pathogens and/or effects normal human skin bacteria. The study consisted of 10 volunteers wearing 9 KTs on their arms for 5 consecutive days. Microorganisms were isolated from fragments collected on the second and fifth day then analyzed. Bacteria were identified using the BIOLOG system. Resistance to selected antibiotics was performed using E-Test. The effect of KTs on the growth of Staphylococcus aureus, Staphylococcus epidermidis , and Micrococcus luteus was evaluated in a diffusion-based assay. We found that KTs accumulated environmental bacteria. Among 22 species 8 were opportunistic pathogens, and all of them exhibited resistance to at least one antibiotic. None of the tapes produced inhibition zones against S. aureus. One tape, Leukotape P, caused growth inhibition in non-pathogenic S. epidermidis and M. luteus. The adhesive material of the tapes inhibited the growth of all tested bacteria. These results indicate that KTs may increase the exposure to antibiotic resistant pathogens which can accumulate from the environment. Further, extended exposure could lead to changes in normal skin microbiota, potentially contributing to increased risks of skin infections. [ABSTRACT FROM AUTHOR]

Streptococcus mutans bacteria form a biofilm called plaque that causes oral diseases, including tooth decay. Therefore, inhibition of biofilm formation is essential to maintaining good oral health. The health and nutritional benefits of Cynodon dactylon are well documented, but very little is known about its use to treat against oral diseases. The aim of this study was to detect the adhesion strength of the S. mutans bacterial biofilm in 100 cases in the Rajshahi region and evaluate the inhibitory activity of different compound extracts of C. dactylon on the S. mutans bacterial biofilm by determining the composition of isolated compounds using phytochemical analysis. Nuclear magnetic resonance (NMR) spectroscopy confirmed that three specific compounds from C. dactylon were discovered in this study: 3,7,11,15 tetramethyl hexadec-2-4dien 1-o1, compound 3,7,11,15 tetramethylhexadec-2-en-1-o1 from phytol derivatives, and stigmasterol. Results indicated that the compound of 3,7,11,15-tetramethyl-hexadec-2-en-1-ol exhibited higher antibiofilm activities on S. mutans than those of the other compound extracts. A lower level of minimum inhibitory concentration was exposed by 3, 7, 11,15 tetramethyl hexadeca-2-en-1-o1 (T2) on S. mutans at 12.5 mL. In this case, the compound of 3,7,11,15 tetramethyl hexadec 2en-1-o1 was used, and patients showed a mean value and standard error reduced from 3.42 ± 0.21 to 0.33 ± 0.06 nm. The maximum inhibition was (80.10%) in the case of patient no. 17, with a value of p < 0.05 found for S. mutans to which 12.5 μL/mL ethyl acetate extract was applied. From these findings, it may be concluded that C. dactylon extracts can be incorporated into various oral preparations to prevent tooth decay.

In the present study, CuO NPs and CuO nano-needles were synthesized using thermal decomposition of Cu(II) complex derived from 2-(4-(trifluoromethoxy)phenylimino)methyl)-6-methoxyphenol (TMPM6MOP) and characterized by UV–vis DRS, PL, FTIR, XRD, and SEM. The monoclinic crystalline nature of the CuO NPs and CuO needles was illustrated by the XRD. The average size of the CuO NPs (30 nm) and CuO needles (diameter 10 nm, length 250 nm) were estimated from XRD and SEM. The prepared CuO needles were used as a fluorescent sensor for the selective and sensitive detection of ciprofloxacin (Cipro) among various antibiotics at diverse pH (4.0–9.0) conditions and the optimized pH = 5.0. The response of Cipro using the CuO needles was linear over the range from 10 to 100 µM L–1. This sensor showed the lowest limit of detection of 0.21 nM and was much lower than the other antibiotic sensors. In addition, the sensor is highly sensitive, selective, and durable in the presence of a range of potentially interfering fluorometric active compounds due to the large surface area and positive surface charge of the CuO needles. Moreover, antimicrobial activities and antioxidant activities were investigated to evaluate the biological potential of the CuO NPs and CuO needles.

The Fe(II), Co(II), Ni(II) Cu(II), Zn(II) and Hg(II) complexes were prepared by reacting their salts with the derived Schiff base ligands from condensing vanillin and o-phenylenediamine with a ratio (1:1), (2:1) respectively. Ligands and their complexes were distinguished using analytical, physical and spectroscopic methods. The elemental analysis values show that stoichiometry to be 1:1 [M:L]. Molar conductivity measurements detect that the complexes are non-electrolytic .From the information obtained through electronic measurements, magnetic sensitivity .The square planar geometry around of Ni(II) and Cu(II), and tetrahedral geometry around of the other metals . The prepared complexes showed different activity towards inhibiting bacterial growth for E. coli k.pneomonia

Frass is a by-product of the larval meal industry and is currently readily available and competitively priced relative to larva meal. In addition to generally high protein and fat content (21.6% and 6%, respectively), frass contains abundant nutrients, chitin, and beneficial microbes. This study evaluates the effect of various levels of frass derived from the larvae of black solder flies fed dried distillers’ grains (DDG) with solubles on growth performance, whole body and fillet proximate compositions and selected hemolymph parameters of Pacific white shrimp, Litopenaeus vannamei. Five isocaloric diets containing frass at levels of 0%, 5%, 10%, 20% and 30% as partial replacement of a combination of soybean meal (SBM), cottonseed meal (CSM), wheat short (WS) and corn meal (CM) on an equal protein basis were offered four times daily to Pacific white shrimp. Four replicate groups of 15 shrimp per tank (initial weight 4.06 ± 0.05 g) were offered experimental diets at 4% total body weight daily for 12 weeks. Shrimp in each aquarium were group-weighed and counted at 2-week intervals and feed inputs were adjusted based on observed survival and weight gain. Although no significant differences were observed in final weight gain, survival, and whole-body composition of shrimp among treatments, there appeared to be quadratic trend of growth with increasing dietary levels of frass. Shrimp fed diets with 5% frass, and 30% frass, showed the highest and lowest weight gain, respectively. Percent lipid content of fillet is linearly decreased with increasing dietary levels of frass and shrimp fed 20% and higher dietary frass level had significantly lower level of fillet lipid. Serum from shrimp fed 20% dietary frass significantly increased inhibition of Vibrio parahaemolyticus growth when compared to that of the control group. However, other hemolymph parameters (total hemocyte count, hemocyanin, serum protein and serum cholesterol) were not significantly affected by dietary treatments. Frass can be incorporated in shrimp diets up to 30% as a substitute for a combination of SBM, CSM, WS and CM without affecting their growth performance, body composition, hemolymph parameters.

The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a non-toxic, natural, biologically active substance, such as fucoidan, to inhibit bacterial growth on similar medical coatings. The fucoidan amount was varied, and its impact on the bioadhesion-influencing surface characteristics, as well as on bacterial cell growth, was investigated. The inclusion of up to 3–4 wt.% brown algae-derived fucoidan in the coatings increases their inhibitory effect, more significantly on the Gram-positive bacterium S. aureus than on the Gram-negative bacterium Escherichia coli. The biological activity of the studied siloxane coatings was ascribed to the formation of a low-adhesive, biologically active surface top layer consisting of siloxane oil and dispersed water-soluble fucoidan particles. This is the first report on the antibacterial activity of fucoidan-containing medical siloxane coatings. The experimental results give reason to expect that relevantly selected, natural biologically active substances can be efficient in the non-toxic control of bacterial growth on medical devices and, as a result, medical device-associated infections.

Tobacco leaf contains antibacterial secondary metabolite compounds, such as phenol, alkaloids, and essential oils. This study compares the potential antibacterial effects of Indonesian tobacco leaf extracted using the heat reflux method (producing an extract) and pyrolysis method (providing a bio-oil). The tobacco leaf extract was challenged against Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The bio-oil from the pyrolysis method showed inhibitory Kirby Bauer zones higher than those of the extract from heat reflux method, with the maximum results in the pyrolysis method indicating zones of 6.35 mm (S. aureus), 5.90 mm (E. faecalis), 3.97 mm (E. coli), and 5.025 mm (P. aeruginosa). Further study analyzed the effectiveness of the disc and well diffusion antibacterial test methods for measuring the antibacterial effect of bio-oils against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. The bio-oil used in the well diffusion test method showed the most significant antibacterial effectiveness. It showed the biggest inhibition zone, with a maximum of 11.65 mm and 8.90 mm for E. coli and P. aeruginosa. Our results showed Nicotiana tabacum var. Virginia Bio Oil from Ponorogo (Indonesia) is a strong potential antimicrobial, especially using well diffusion test. [ABSTRACT FROM AUTHOR]

The opportunistic human pathogen Pseudomonas aeruginosa exhibits great resistance to antibiotics; so, new therapeutic agents are urgently needed. Since polyamines levels are incremented in infected tissues, we explored whether the formation of a toxic aldehyde in polyamines degradation can be exploited in combating infection. We cloned the gene encoding the only aminoaldehyde dehydrogenase involved in P. aeruginosa polyamines‐degradation routes, PaPauC, overexpressed this enzyme, and found that it oxidizes 3‐aminopropionaldehyde (APAL) and 3‐glutamyl‐3‐aminopropionaldehyde (GluAPAL) − produced in spermine (Spm), spermidine (Spd), and diaminopropane (Dap) degradation, as well as 4‐aminobutyraldehyde (ABAL) and 4‐glutamyl‐4‐aminobutyraldehyde (GluABAL) − formed in putrescine (Put) degradation. As the catalytic efficiency of PaPauC with APAL was 30‐times lower than with GluAPAL, and GluAPAL is predominantly formed, APAL will be poorly oxidized 'in vivo'. We found polyamines‐induced increases in the PaPauC activity of cell crude‐extracts and in the expression of the PapauC gene that were diminished by glucose. Spm, Spd, or Dap, but not Put, were toxic to P. aeruginosa even in the presence of other carbon and nitrogen sources, particularly to a strain with the PapauC gene disrupted. APAL, but not GluAPAL, was highly toxic even to wild‐type cells, suggesting that its accumulation, particularly in the absence of, or low, PaPauC activity is responsible for the toxicity of Spm, Spd, and Dap. Our results shed light on the toxicity mechanism of these three polyamines and strongly support the critical role of PaPauC in this toxicity. Thus, PaPauC emerges as a novel potential drug target whose inhibition might help in combating infection by this important pathogen. [ABSTRACT FROM AUTHOR]

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The application of nanotechnology has brought about advancements in environmental and medical applications. Recently, zinc oxide nanoparticle (ZnO NP) is commonly used to treat a wide range of bacterial and fungal skin infections due to its antimicrobial property. This investigation was intended to study the antimicrobial effect of ZnO NP on Pseudomonas aeruginosa by testing the bacterial inhibition and the morphological damages caused by ZnO NP to P. aeruginosa. The results of this study exhibited a typical dose-dependent and significant (p < 0:05) inhibition of the growth of P. aeruginosa treated with 5 to 150 µg/mL of ZnO NP. The polysaccharides and polypeptides from P. aeruginosa cell wall were found to be associated with the attachment of ZnO NPs to bacterial cells as illustrated in the Fourier Transform Infrared (FTIR) spectrum. Furthermore, Scanning Electron Microscopy (SEM) images displayed the surface attachment of ZnO NPs on bacteria and the morphological changes, such as disrupted cell wall integrity, cell bending, and cell distortion, as a result of ZnO NPs interaction on the cell wall of P. aeruginosa. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) have been used in the treatment of bacterial infections due to their antibacterial properties. The present study was aimed to explore the antibacterial effects of ZnO NPs on Streptococcus pyogenes. The antibacterial properties were evaluated by investigating the growth inhibition and oxidative stress effects of ZnO NPs on S. pyogenes. The bacterial growth inhibition was determined through the percentage of reduction in the turbidity of bacterial suspension and bacterial colony upon treating with ZnO NPs, while the oxidative stress of ZnO NPs on bacterial cells were assessed by measuring the levels of reactive oxygen species (ROS) and lipid peroxidation. The results showed the dose dependent and significant (p < 0.05) growth inhibition and oxidative stress effects on S. pyogenes for 10 to 100 μg/mL ZnO NPs at 24 h. Fourier-transform infrared spectrometry (FTIR) analysis confirmed the binding of ZnO NPs to polypeptides and glycogen from the bacterial cell wall. Further, the scanning electron microscopy (SEM) results showed the attachment of ZnO NPs to bacterial cell wall and the resultant cell wall disruption and cell damage. The study results confirmed the antimicrobial effects of ZnO NPs on S. pyogenes.

Colostrum contains bioactive components protecting the newborn intestine against bacteria. It is unclear how to optimize processing conditions with highest product bioactivity. Non-pasteurized (BC00), standard-pasteurized (72 °C-15 s, BC72), gently-pasteurized bovine colostrums without (63 °C-30 min, BC63) and with gamma-irradiation (BC63g) were tested for effects on bacterial growth inhibition (Escherichia coli, Staphylococcus aureus and S. epidermidis), intestinal epithelial cell (IEC) proliferation and cytokine secretion in vitro. Thermal processing decreased endogenous bacteria and IgG levels. All BCs inhibited bacterial growth 1–2 h after inoculation, but only BC00, BC63 and BC63g retained activity after 4–24 h. After 4 h, the activity against S. epidermidis of BC63g was lower than BC00 but still potent when mixed with formula. All BCs stimulated IEC proliferation, with the most pronounced responses for BC00. Only BC00 and BC63 increased IL-8 secretion in lipopolysaccharide-stimulated IECs. Thermal processing reduced bioactivity and combined gentle pasteurization and gamma-irradiation improved BC sterility and bioactivity, relative to standard pasteurization.

The pertussis vaccination is highly recommended for infants, children, and pregnant women. Despite a high coverage of vaccination, pertussis continues to be of public health concern as a re-emerging infectious disease. The mechanism by which vaccine-elicited anti-pertussis antibodies mediate direct bactericidal effects is poorly understood. In this study, we showed that the interaction of B. pertussis with A549 epithelial cells induce release of biological factors which enhance bacteria growth. Complement-depleted antisera from vaccine-immunized guinea pigs or monoclonal antibodies targeting FHA and FIM mediate bacteria aggregation and elicit bactericidal effects. Our in vitro results indicated that aggregation of bacteria through anti-FIM and anti-FHA specific antibodies is one of the major biological mechanisms to clear bacterial infections and restore epithelial cell survival in vitro. Our data also indicates that the anti-pertussis antibodies reduce secretion of proinflammatory chemokines and cytokines by preventing interaction of B. pertussis with host cells. The results of this study not only demonstrate mechanism of action of anti-FIM and anti-FHA antibodies, but also opens translational applications for potential therapeutic approaches or development of analytical assays such as in vitro potency assays.

ZnO nanoparticles (NPS) with different morphologies were synthesized, and the antibacterial and anticancer activity was studied, herein. The physicochemical characterization was carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and UV–visible. To study the antibacterial and anticancer capability of ZnO NPS, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria and HeLa cancer cells were exposed at different doses of ZnO NPS (7–250 µg/mL). TEM analysis confirmed the obtention of spherical, hexagonal and rod ZnO NPS with an average diameter of 20 ± 4 nm, 1.17 ± 0.3 µm and 1.11 ± 1.2 µm, respectively. XRD diffractograms showed the characteristic pattern of crystalline ZnO in wurtzite phase. FTIR and UV–vis spectra showed slight differences of the main absorption peaks, revealing that different ZnO NPS morphologies may cause shifts in spectra. Biological essays showed that the number of E. coli and S. aureus bacteria as well as HeLa cells decreases linearly by increasing the nanoparticle concentration. However, the best anticancer and antibacterial activity was shown by spherical ZnO NPS at 100 µg/mL. The better capability of spherical ZnO NPS than hexagonal and rod ZnO NPS is related with its small particle size. The present results suggest that the spherical ZnO NPS has a great potential as an antibacterial and anticancer agent. [ABSTRACT FROM AUTHOR]

The pertussis vaccination is highly recommended for infants, children, and pregnant women. Despite a high coverage of vaccination, pertussis continues to be of public health concern as a re-emerging infectious disease. The mechanism by which vaccine-elicited anti-pertussis antibodies mediate direct bactericidal effects is poorly understood. In this study, we showed that the interaction of B. pertussis with A549 epithelial cells induce release of biological factors which enhance bacteria growth. Complement-depleted antisera from vaccine-immunized guinea pigs or monoclonal antibodies targeting FHA and FIM mediate bacteria aggregation and elicit bactericidal effects. Our in vitro results indicated that aggregation of bacteria through anti-FIM and anti-FHA specific antibodies is one of the major biological mechanisms to clear bacterial infections and restore epithelial cell survival in vitro. Our data also indicates that the anti-pertussis antibodies reduce secretion of proinflammatory chemokines and cytokines by preventing interaction of B. pertussis with host cells. The results of this study not only demonstrate mechanism of action of anti-FIM and anti-FHA antibodies, but also opens translational applications for potential therapeutic approaches or development of analytical assays such as in vitro potency assays. [ABSTRACT FROM AUTHOR]

We developed a synthetic RNA approach to identify growth inhibition sequences by cloning random 24-nucleotide (nt) sequences into an arabinose-inducible expression vector. This vector expressed a small RNA (sRNA) of ∼140 nt containing a 24 nt random sequence insert. After transforming Escherichia coli with the vector, 10 out of 954 transformants showed strong growth defect phenotypes and two clones caused cell lysis. We then examined growth inhibition phenotypes in the Salmonella Typhimurium LT2 strain using the twelve sRNAs that exerted an inhibitory effect on E. coli growth. Three of these clones showed strong growth inhibition phenotypes in S. Typhimurium LT2. The most effective sRNA contained the same insert (N1) in both bacteria. The 24 nt random sequence insert of N1 was abundant in guanine residues (ten out of 24 nt), and other random sequences causing growth defects were also highly enriched for guanine (G) nucleotides. We, therefore, generated clones that express sRNAs containing a stretch of 16 to 24 continuous guanine sequences (poly-G 16 , -G 18 , -G 20 , -G 22 , and -G 24). All of these clones induced growth inhibition in both liquid and agar plate media and the poly-G 20 clone showed the strongest effect in E. coli. These results demonstrate that our sRNA expression system can be used to identify nucleotide sequences that are potential candidates for oligonucleotide antimicrobial drugs. • Inducible sRNA expression vector was developed for screening growth defect clones. • Artificial guanine-rich sRNAs cause growth inhibition in E. coli and Salmonella. • Polyguanine (poly-G 20) -containing sRNA exerts strong growth inhibition in E. coli. [ABSTRACT FROM AUTHOR]

Despite the existence of many attempts at nerve tissue engineering, there is no ideal strategy to date for effectively treating defective peripheral nerve tissue. In the present study, well-aligned poly (L-lactic acid) (PLLA) nanofibers with varied nano-porous surface structures were designed within different ambient humidity levels using the stable jet electrospinning (SJES) technique. Nanofibers have the capacity to inhibit bacterial adhesion, especially with respect to Staphylococcus aureus (S. aureus). It was noteworthy to find that the large nano-porous fibers were less detrimentally affected by S. aureus than smaller fibers. Large nano-pores furthermore proved more conducive to the proliferation and differentiation of neural stem cells (NSCs), while small nano-pores were more beneficial to NSC migration. Thus, this study concluded that well-aligned fibers with varied nano-porous surface structures could reduce bacterial colonization and enhance cellular responses, which could be used as promising material in tissue engineering, especially for neuro-regeneration.

Graphene-polymer nanocomposites are innovative materials that have attracted much attention due to their novel features. Herein, we report photocatalytic and antibacterial properties of GNP-PPy nanocomposites. The formation of nanocomposites was confirmed by various characterization techniques. The assembly of GNPs and PPy NPs with optimized GNP content amazingly increased the photocatalytic degradation of bromophenol blue (BPB) up to 93% under solar light irradiation in 120 min. The antibacterial assay revealed that 50% GNPs-PPy nanocomposite showed a best (32.43%) inhibition of growth against a Gram negative bacteria E. coli. The GNP-PPy nanocomposites can possibly be utilized as multifunctional material for wastewater treatment and as antimicrobial agent. Image 1 • Graphene/PPy nanocomposites show good photocatalytic activity under sunlight. • The materials also show moderate antibacterial activity. [ABSTRACT FROM AUTHOR]

• Pasteurization reduces IgG levels and anti-bacterial effects of bovine colostrum (BC). • Pasteurization reduces effects on intestinal cell proliferation and cytokine secretion. • Standard pasteurization is more detrimental than pasteurization at 63 °C for 30 min. • Gently-pasteurized and gamma-irradiated BC has improved sterility and bioactivity. Colostrum contains bioactive components protecting the newborn intestine against bacteria. It is unclear how to optimize processing conditions with highest product bioactivity. Non-pasteurized (BC00), standard-pasteurized (72 °C-15 s, BC72), gently-pasteurized bovine colostrums without (63 °C-30 min, BC63) and with gamma-irradiation (BC63g) were tested for effects on bacterial growth inhibition (Escherichia coli, Staphylococcus aureus and S. epidermidis), intestinal epithelial cell (IEC) proliferation and cytokine secretion in vitro. Thermal processing decreased endogenous bacteria and IgG levels. All BCs inhibited bacterial growth 1–2 h after inoculation, but only BC00, BC63 and BC63g retained activity after 4–24 h. After 4 h, the activity against S. epidermidis of BC63g was lower than BC00 but still potent when mixed with formula. All BCs stimulated IEC proliferation, with the most pronounced responses for BC00. Only BC00 and BC63 increased IL-8 secretion in lipopolysaccharide-stimulated IECs. Thermal processing reduced bioactivity and combined gentle pasteurization and gamma-irradiation improved BC sterility and bioactivity, relative to standard pasteurization. [ABSTRACT FROM AUTHOR]

A fragment of 23S ribosomal RNA (nucleotides 1906–1924 in E. coli ), termed Helix 69, forms a hairpin that is essential for ribosome function. Helix 69 forms a conformationally flexible inter-subunit connection with helix 44 of 16S ribosomal RNA, and the nucleotide A1913 of Helix 69 influences decoding accuracy. Nucleotides U1911 and U1917 are post-transcriptionally modified with pseudouridines ( Ψ ) and U1915 with 3-methyl- Ψ . We investigated Helix 69 as a target for a complementary synthetic oligonucleotide – peptide nucleic acid (PNA). We determined thermodynamic properties of Helix 69 and its complexes with PNA and tested the performance of PNA targeted at Helix 69 in inhibiting translation in cell-free extracts and growth of E. coli cells. First, we examined the interactions of a PNA oligomer complementary to the G1907–A1919 fragment of Helix 69 with the sequences corresponding to human and bacterial species (with or without pseudouridine modifications). PNA invades the Helix 69 hairpin creating stable complexes and PNA binding to the pseudouridylated bacterial sequence is stronger than to Helix 69 without any modifications. Second, we confirmed the binding of PNA to 23S rRNA and 70S ribosomes. Third, we verified the efficiency of translation inhibition of these PNA oligomers in the cell-free translation/transcription E. coli system, which were in a similar range as tetracycline. Next, we confirmed that PNA conjugated to the (KFF) 3 K transporter peptide inhibited E. coli growth in micromolar concentrations. Overall, targeting Helix 69 with PNA or other sequence-specific oligomers could be a promising way to inhibit bacterial translation. [ABSTRACT FROM AUTHOR]

Olive leaf extract (OLE) has been used traditionally as a herbal supplement since it contains polyphenolic compounds with beneficial properties ranging from increasing energy levels, lowering blood pressure, and supporting the cardiovascular and immune systems. In addition to the beneficial effects on human health, OLE also has antimicrobial properties. The aim of this work was to investigate the antimicrobial effect of OLE against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. Our results demonstrated that at a concentration of 62.5 mg/ml, OLE almost completely inhibited the growth of these three pathogens. In addition, OLE also reduced cell motility in L. monocytogenes, which correlated with the absence of flagella as shown by scanning electron microscopy. Moreover, OLE inhibited biofilm formation in L. monocytogenes and S. Enteritidis. Taken together, OLE, as a natural product, has the potential to be used as an antimicrobial to control foodborne pathogens. [ABSTRACT FROM AUTHOR]

The ubiquitous presence of the plasticizer di (2-ethylhexyl) phthalate (DEHP) in the environment is of concern due to negative biological effects associated with it and its metabolites. In particular, the metabolite mono (2-ethylhexyl) phthalate (MEHP) is a potential endocrine disruptor. Earlier work had identified the diester di (2-ethylhexyl) maleate (DEHM) as a potential greener candidate plasticizer to replace DEHP, yet its biodegradation rate was reported to be slow. In this study, we modified the side chains of maleate diesters to be linear (i.e., unbranched) alkyl chains that varied in length from ethyl to n-octyl. The plasticization efficiency of these compounds blended into PVC at 29 wt.% increased with the overall length of the molecule, but all compounds performed as well as or better than comparable samples with DEHP. Tests conducted with the equally long DEHM and dihexyl maleate (DHM) showed that branching has no effect on glass transition temperature ( T g ) reduction efficiency. Biodegradation experiments with the common soil bacterium Rhodococcus rhodocrous in the presence of the plasticizer showed acceptable hydrolysis rates of maleates with unbranched side chains, while the branched DEHM showed almost no degradation. The addition of hexadecane as auxiliary carbon source improved hydrolysis rates. Temporary buildup of the respective monoester of the compounds were observed, but only in the case of the longest molecule, dioctyl maleate (DOM), did this buildup lead to growth inhibition of the bacteria. Maleates with linear side chains, if designed and tested properly, show promise as potential candidate plasticizers as replacements for DEHP. [ABSTRACT FROM AUTHOR]

Antibiotic susceptibility testing is very important in antibiotic therapy. Traditional methods to determine antibiotic susceptibility include disk diffusion and broth dilution. However, these tests are always labor intensive, time-consuming, and need large amounts of reagents. In this paper, we demonstrated a novel pump-free micro-device that enables quantitative and high-throughput bacterial growth inhibition analysis. This device consists of a series of wells and diffusion-based antibiotic gradient channels. The wells serve as antibiotic sources and buffer sinks, and we could easily observe the bacterial growth in the gradient channels .The design of the multi-wells is adapted to the commercialized multi-channel pipette, which makes it very convenient for loading reagents into the wells. For each assay, only about 20 μL antibiotic solution is needed. As a demonstration, we used both fluorescence images and dark-field images to quantify the bacterial growth inhibition effect under different antibiotics. The quantitative data of bacterial growth inhibition under different antibiotics can be obtained within 3 to 4 h. Considering the simple operation process and the high-throughput and quantitative result this device can offer, it has great potential to be widely used in clinics and may be useful for the study of the kinetics of bacterial growth. [ABSTRACT FROM AUTHOR]

Background: Human platelets are a rich reservoir of molecules that promote regenerative processes and microbicidal activity. This activity might be increased by concentration in platelet-rich plasma (PRP) products and modulated by the presence of leukocytes. Despite extensive use in clinical procedures, only few studies have investigated PRP's real microbicidal potential. Therefore, this study aimed at comparing the in vitro microbicidal activity of platelets and leukocyte-enriched PRP (L-PRP) to pure platelet-rich plasma (P-PRP) and the contribution of leukocytes to microbicidal properties. Antimicrobial effects of P- and L-PRP were tested against Escherichia Coli, Staphylococcus Aureus, Klebsiella Pneumoniae, Pseudomonas Aeruginosa and Enterococcus Faecalis. Furthermore, L-PRP was frozen (L-PRP cryo) to assess whether the preparation maintained in vitro characteristics. Microbicidal proteins released by the three preparations were also evaluated. Results: L-PRP, L-PRP cryo and P-PRP generally induced comparable bacterial growth inhibition for up to 4 h' incubation, range 1-4 log. MIP-1a, RANTES, GRO-a, IL-8, NAP-2, SDF-1a and IL-6 showed strong microbicidal potential. Conclusions: We found in vitro antibacterial activity of L-PRP and P-PRP and the possibility to cryopreserve L-PRP, without important changes to its effectiveness; similar microbicidal activity between preparations containing or not leukocytes; and the contribution of three new molecules (NAP-2, SDF-1a and IL-6). [ABSTRACT FROM AUTHOR]

Pacifastin-related inhibitor is a new family of serine protease inhibitors that regulate the proteolytic cascade in multiple biological processes. Contrary to the knowledge on the structure and inhibitory mechanism of pacifastin-like members in locust, very little is known about their functions. Here, we report the inhibitory activities in relation to the structural characteristics of pacifastin light chain (PtPLC) gene identified from the swimming crab Portunus trituberculatus . The mature PtPLC and five PLD-related domains with critical residues were expressed in Escherichia coli , and assayed for their activities. The recombinant PtPLC (rPtPLC) displayed inhibitory activities against trypsin and chymotrypsin in a dose dependent manner, with a preference for trypsin. Except for rPtPLC-D4, the other four rPtPLC-related domains could inhibit at least one of serine proteases. The enzyme specificity of PtPLC domains generally corresponded to the nature of the P1 residue at the reactive site. rPtPLC was able to inhibit the growth of Gram-negative bacteria Vibrio alginolyticus and Pseudomonas aeruginosa , but not the Gram-positive bacterium and fungus tested. Further phenoloxidase (PO) assay showed the rPtPLC could depress the crab proPO system activation in vitro , and lead to 72.8% inhibition of PO activity at the concentration of 9.11 μM. It also suppressed proPO activation induced by rPtcSP and rPtSPH1. As the first functional study of the recombinant PLC protein in crustaceans, the present results together indicate that PtPLC functions in the crab immune response possibly via inhibiting bacterial growth and regulating the proPO system. [ABSTRACT FROM AUTHOR]

The restriction of effective insecticides has facilitated the woolly apple aphid ( WAA) Eriosoma lanigerum to become a major pest in apple orchards in Western Europe. It has also promoted alternative control strategies such as the use of entomopathogenic nematodes ( EPN). We evaluated the control capacity of six commercially available EPN, viz. Heterorhabditis bacteriophora, Heterorhabditis megidis, Steinernema carpocapsae, Steinernema feltiae, Steinernema glaseri and Steinernema kraussei. We assessed the potential of these EPN to colonize and parasitize E. lanigerum in an in vitro multiwell test. Only S. carpocapsae caused higher mortality (20-40%) than the control treatment (water). However, the mortality observed with S. carpocapsae was found to be a test artefact and not induced by its specific entomopathogenic activity. A similar mortality range was recorded when applying the non-entomopathogenic nematode Pratylenchus thornei in the same multiwell test set-up. This result warrants careful interpretation of parasitism in these artificial test conditions. The failure of EPN activity was supported in further experiments by frequently finding S. carpocapsae inside living WAA. The presence of the EPN had no effect on aphid reproduction as numbers of 'large' embryos in EPN-colonized and non-colonized females were similar. In addition, the dauer juveniles did not recover in E. lanigerum reflecting that S. carpocapsae could not develop inside the WAA. We further demonstrated that growth of the EPN-symbiotic bacteria Xenorhabdus nematophila and Photorhabdus luminescens is inhibited by the body fluid of the WAA, and we speculate that this antibacterial activity is the cause of the unsuccessful parasitization of the WAA by the EPN. This antibiosis inside the body of E. lanigerum would prevent production of the endotoxins by the bacterial symbionts that are essential for entomopathogenicity and insect control. [ABSTRACT FROM AUTHOR]

Serpin or serine protease inhibitor is the largest family of protease inhibitors involved in many innate immune pathways, particularly the prophenoloxidase (proPO) activating system in arthropod. Here, we report the molecular and functional characterization of PtSerpin identified from the swimming crab Portunus trituberculatus. The genomic sequence encoding mature peptide of PtSerpin gene contained two exons of 84 and 1098 bp separated by one intron of 111 bp. The recombinant PtSerpin (rPtSerpin) with a predicted size of 44 kDa was expressed in Escherichia coli system, purified and assayed for its activities. The rPtSerpin exhibited inhibitory activity against trypsin in a dose-dependent manner, but did not affect chymotrypsin, which could define a role for PtSerpin as a trypsin inhibitor. The rPtSerpin could inhibit the growth of Gram-negative bacterium Vibrio alginolyticus, but not the tested Gram-positive bacterium and fungus. Further phenoloxidase (PO) assay showed PO activity was dramatically increased in hemocyte lysate supernatant of P. trituberculatus upon bacterial challenge. The rPtSerpin could depress the crab proPO system activation in vitro, and it could lead to 100% inhibition of PO activity under the concentration of 8.62 µM. Moreover, the rPtSerpin was able to inhibit the PO activity induced by rPtcSP and rPtSPH1. These results together indicate that PtSerpin is a potential trypsin inhibitor and may participate in crab innate immunity by the inhibition of bacterial growth and the regulation of proPO system. [ABSTRACT FROM AUTHOR]

Purpose: Two antiseptic solutions were investigated for their effect on bacterial growth inhibition. Materials and Methods: A total of 38 patients were included in this study, who visited Daegu Catholic Medical Center from August 2, 2011 to September 2, 2011. Bacterial culture was performed at the pre-scrub, post-scrub, and postoperation; patients were divided into two groups according to use of povidone iodine (3.75%) and povidone iodine with Softa-Man® as antiseptic agents at the surgical. Results: Comparison between the antiseptic solutions showed a significant difference for the presence of gram positive cocci (p=0.034), however, no difference was observed for the presence of gram positive bacilli (p=0.838). As the scrub time increased, the positive detection ratio of bacteria decreased (p=0.000), and decreased significantly at more than 120 seconds. However, positive detection ratio of bacteria increased significantly at more than 300 seconds in cases with povidone iodine only (p=0.014). Glove wearing time did not have a significant influence on the positive detection ratio of bacteria, and no significant difference was observed between the antiseptic solutions (p=0.143). Conclusion: Considering the positive detection ratio of bacteria when using povidone iodine only, the appropriate scrub time should be between 4 and 5 minutes. When using both antiseptics, at least 2 minutes of scrub time is needed. [ABSTRACT FROM AUTHOR]

Background and Objective Porphyromonas gingivalis is a major etiological agent in the development and progression of periodontal diseases. In this study, we isolated a cell growth inhibitor against P. gingivalis species from rice protein extract. Material and Methods The cell growth inhibitor active against P. gingivalis was purified from polished rice extract using a six-step column chromatography process. Its antimicrobial properties were investigated through microscope analysis, spectrum of activity and general structure. Results The inhibitor was identified as AmyI-1, an α-amylase, and showed significant cell growth inhibitory activity against P. gingivalis species. Scanning electron microscopy micrograph analysis and bactericidal assay indicated an intriguing possibility that the inhibitor compromises the cell membrane structure of the bacterial cells and leads to cell death. Moreover, α-amylases from human saliva and porcine pancreas showed inhibitory activity similar to that of AmyI-1. Conclusions This is the first study to report that α-amylases cause cell death of periodontal pathogenic bacteria. This finding highlights the potential importance and therapeutic potential of α-amylases in treating periodontal diseases. [ABSTRACT FROM AUTHOR]

Abstract: In all cells, ATP-dependent proteases play central roles in the controlled degradation of short-lived regulatory or misfolded proteins. A hallmark of these enzymes is that proteolytic active sites are sequestered within a compartmentalized space, which is accessible to substrates only when they are fed into the cavity by protein-unfolding ATPases. HslVU is a prototype of such enzymes, consisting of the hexameric HslU ATPase and the dodecameric HslV protease. HslV forms a barrel-shaped proteolytic chamber with two constricted axial pores. Here, we report that structural alterations of HslV's pore motif dramatically affect the proteolytic activities of both HslV and HslVU complexes. Mutations of a conserved pore residue in HslV (Leu88 to Ala, Gly, or Ser) led to a tighter binding between HslV and HslU and a dramatic stimulation of both the proteolytic and ATPase activities. Furthermore, the HslV mutants alone showed a marked increase of basal hydrolytic activities toward small peptides and unstructured proteins. A synthetic peptide of the HslU C-terminal tail further stimulated the proteolytic activities of these mutants, even allowing degradation of certain folded proteins in the absence of HslU. Moreover, expression of the L88A mutant in Escherichia coli inhibited cell growth, suggesting that HslV pore mutations dysregulate the protease through relaxing the pore constriction, which normally prevents essential cellular proteins from random degradation. Consistent with these observations, an X-ray crystal structure shows that the pore loop of L88A-HslV is largely disordered. Collectively, these results suggest that substrate degradation by HslV is controlled by gating of its pores. [Copyright &y& Elsevier]

Abstract: The aim of this study was to explore the influence of a moderate static magnetic field (SMF) of different densities on Escherichia coli and Pseudomonas putida that are commonly found in wastewater treatment plants. In line with literature reports that SMF increases the efficiency of wastewater treatment the findings of this study indicated that SMF negatively influenced the growth but positively influenced the enzymatic activities and ATP levels of the two model bacteria. The inhibitory effect of SMF on growth of E. coli and P. putida was most pronounced at their optimal growth temperature (37°C and 28°C respectively) and was reversible shortly after the SMF had been terminated. Finally, the results suggested that the induced energy metabolism reflected in higher dehydrogenase activities and ATP levels may be more important for survival, and adaptation to SMF induced stress than the increase in the expression of the rpoS gene. [Copyright &y& Elsevier]

Abstract: Pediocin PA-1 is an antimicrobial peptide produced by lactic acid bacteria (LAB) that has been sufficiently well characterised to be used in food industry as a biopreservative. Sulphur dioxide is the traditional antimicrobial agent used during the winemaking process to control bacterial growth and wine spoilage. In this study, we describe the effect of pediocin PA-1 alone and in combination with sulphur dioxide and ethanol on the growth of a collection of 53 oenological LAB, 18 acetic acid bacteria and 16 yeast strains; in addition, production of pediocin PA-1 by Pediococcus acidilactici J347-29 in presence of ethanol and grape must is also reported. Inhibitory concentrations (IC) and minimal bactericide concentrations of pediocin PA-1 were determined against LAB, and revealed a bacteriostatic effect. Oenococcus oeni resulted more sensitive to pediocin PA-1 (IC50 = 19 ng/ml) than the other LAB species (IC50 = 312 ng/ml). Cooperative inhibitory effects of pediocin PA-1 and either sulphur dioxide or ethanol were observed on LAB growth. Moreover, the pediocin PA-1 producing P. acidilactici strain J347-29 was able to grow and produce the bacteriocin in presence of ethanol (up to 4% ethanol in the fermentation broth) and grape must (up to 80%), which indicated that pediocin PA-1 can be considered as a potential biopreservative in winemaking. [Copyright &y& Elsevier]

Abstract: Tetracycline antibiotics are widely used in human and veterinary medicine; however, residual amounts of these antibiotics in the environment are of concern since they could contribute to selection of resistant bacteria. In this study, tetracycline (TC), chlortetracycline (CTC), doxycycline (DC) and oxytetracycline (OTC) were treated with laccase from the white rot fungus Trametes versicolor in the presence of the redox mediator 1-hydroxybenzotriazole (HBT). High performance liquid chromatography demonstrated that DC and CTC were completely eliminated after 15min, while TC and CTC were eliminated after 1h. This system also resulted in a complete loss of inhibition of growth of Escherichia coli and Bacillus subtilis and the green alga Pseudokirchneriella subcapitata with decreasing tetracycline antibiotic concentration. These results suggest that the laccase–HBT system is effective in eliminating tetracycline antibiotics and removing their ecotoxicity. [Copyright &y& Elsevier]

Abstract: The antimicrobial and preservative agent triclosan (TCS) is an emerging and persistent pollutant with a ubiquitous presence in the aquatic environment. Thus, TCS was treated with manganese peroxidase (MnP), laccase and the laccase-mediator system with 1-hydroxybenzotriazole. MnP was most effective in eliminating TCS among the three enzymatic treatments, with TCS concentration being reduced by about 94% after 30min following treatment with 0.5nkatmL−1 MnP and being almost completely eliminated after 60min. Furthermore, MnP (0.5nkatmL−1) caused the complete loss of bacterial growth inhibition by TCS after 30min and reduced the algal growth inhibition of TCS by 75% and 90% after 30 and 60min, respectively. These results strongly suggest that MnP is effective in removing the ecotoxicity of TCS. [Copyright &y& Elsevier]

Sibling Paenibacillus dendritiformis bacterial colonies grown on low-nutrient agar medium mutually inhibit growth through secretion of a lethal factor. Analysis of secretions reveals the presence of subtilisin (a protease) and a 12 kDa protein, termed sibling lethal factor (SIf). Purified subtilisin promotes the growth and expansion of P. dendritiformis colonies, whereas SIf is lethal and lyses P. dendritiformis cells in culture. SIf is encoded by a gene belonging to a large family of bacterial genes of unknown function, and the gene is predicted to encode a protein of approximately 20 kDa, termed dendritiformis sibling bacteriocin. The 20 kDa recombinant protein was produced and found to be inactive, but exposure to subtilisin resulted in cleavage to the active, 12 kDa form. The experimental results, combined with mathematical modeling, show that subtilisin serves to regulate growth of the colony. Below a threshold concentration, subtilisin promotes colony growth and expansion. However, once it exceeds a threshold, as occurs at the interface between competing colonies, SIf is then secreted into the medium to rapidly reduce cell density by lysis of the bacterial cells. The presence of genes encoding homoloys of dendritiformis sibling bacteriocin in other bacterial species suggests that this mechanism for self-regulation of colony growth might not be limited to P. dendritiformis. [ABSTRACT FROM AUTHOR]

Bacillus anthracis, the causative agent of anthrax, is a worldwide problem because of the need for effective treatment of respiratory infections shortly after exposure. One potential key enzyme of B. anthracis to be targeted by antiproliferative drugs is ribonucleotide reductase. It provides deoxyribonucleotides for DNA synthesis needed for spore germination and growth of the pathogen. We have cloned, purified, and characterized the tyrosyl radical-carrying NrdF component of B. anthracis class lb ribonucleotide reductase. Its EPR spectrum points to a hitherto unknown three-dimensional geometry of the radical side chain with a 60° rotational angle of Cα-(Cβ-C1)-plane of the aromatic ring. The unusual relaxation behavior of the radical signal and its apparent lack of line broadening at room temperature suggest a weak interaction with the nearby diiron site and the presence of a water molecule plausibly bridging the phenolic oxygen of the radical to a ligand of the diiron site. We show that B. anthracis cells are surprisingly resistant to the radical scavenger hydroxyurea in current use as an antiproliferative drug, even though its NrdF radical is efficiently scavenged in vitro. Importantly, the antioxidants hydroxylamine and N-methyl hydroxylamine scavenge the radical several orders of magnitude faster and prevent B. anthrads growth at several hundred-fold lower concentrations compared with hydroxyurea. Phylogenetically, the B. anthracis NrdF protein clusters together with NrdFs from the pathogens Bacillus cereus, Bacillus thuringiensis, Staphylococcus aureus, and Staphylococcus epidermidis. We suggest the potential use of N-hydroxylamines in combination therapies against infections by B. anthracis and closely related pathogens. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify Antarctic microorganisms with the ability to produce cold-active antimicrobial compounds with potential for use in chilled food preservation. Colonies (4496) were isolated from 12 Antarctic soil samples and tested against Listeria innocua, Pseudomonas fragi and Brochothrix thermosphacta. Thirteen bacteria were confirmed as being growth-inhibitor producers (detection rate 0.29%). When tested against a wider spectrum of eight target organisms, some of the isolates also inhibited the growth of L. monocytogenes and Staphylococcus aureus. Six inhibitor producers were psychrotrophic (growth optima between 18 and 24 °C), halotolerant (up to 10% NaCl) and catalase-positive; all but one were Gram-positive and oxidase-positive. The inhibitors produced by four bacteria were sensitive to proteases, suggesting a proteinaceous nature. Four of the inhibitor–producers were shown to be species of Arthrobacter, Planococcus and Pseudomonas on the basis of their 16S rRNA gene sequences and fatty acid compositions. It was concluded that Antarctic soils represent an untapped reservoir of novel, cold-active antimicrobial-producers. [Copyright &y& Elsevier]

By using differential display PCR, we obtained a cDNA clone encoding a gloverin homologue from the cabbage looper, Trichoplusia ni. The expression of the gene was induced by bacterial infections. The gene codes for a 174 amino acid residue protein, including a signal sequence and a prosegment. The deduced mature protein is 14 kDa and shows 58% and 49% identity to P2 from Helicoverpa armigera and to Hyalophora gloveri gloverin, respectively. The protein was detected in hemolymph and hemocytes from bacteria-immunized animals. We expressed gloverin using the baculovirus expression system. N-terminal amino acid sequence analysis showed that the purified protein contained a propart. This progloverin inhibited the growth of E. coli and the activity is comparable to that of H. gloveri mature gloverin. Processing of progloverin was possible in vitro, using human furin. [Copyright &y& Elsevier]