Gram-negative Bacterium Pseudomonas Research Articles

Antifouling and Antimicrobial Coatings from Zwitterionic and Cationic Binary Polymer Brushes Assembled via “Click” Reactions

Controlled architecture of bifunctional polymers on surfaces is highly challenged because of the stringent reaction conditions or tedious operations required for surface modification. Herein, a simple and effective method was developed to assemble zwitterionic and cationic binary polymer brushes onto polydopamine-anchored stainless steel (SS) surfaces. Zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was first graft polymerized from the functionalized SS surface via thiol–ene “click” reaction. Alkynyl-modified cationic poly(2-(methacryloyloxy) ethyl trimethylammonium chloride) (alkynyl-PMETA) was subsequently introduced via azide–alkyne “click” reaction. After the grafting of PMPC/PMETA binary polymer brushes, the resulting functionalized SS surfaces can cooperatively reduce the adhesion of Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Pseudomonas sp., as well as the attachment of microalgae Amphora coffeaeformis. In addition, the binary polymer brus...

Draft Genome Sequence of a Pseudomonas aeruginosa NA04 Bacterium Isolated from an Entomopathogenic Nematode.

ABSTRACTWe report the draft genome sequence of Gram-negative bacterium Pseudomonas aeruginosa NA04, isolated from the entomopathogenic nematode Heterorhabditis indica MOR03. The draft genome consists of 54 contigs, a length of 6.37 Mb, and a G+C content 66.49%.

SYNTHESIS OF ARYL (5-SUBSTITUTED BENZOFURAN-2-YL) CARBAMATE DERIVATIVES AS ANTIMICROBIAL AGENTS

ABSTRACTObjectives: Benzofurans are very interesting heterocycles, which are available in nature and show a wide range of pharmacological activities, viz.,antifungal, antibacterial, antitumor, antimalarial and antioxidant activity.Methods: A convenient method for the preparation of aryl (5-substituted benzofuran-2-yl) carbamate derivatives 6a-6j has been developed. Thetarget compounds 1-(5-nitrobenzofuran-2-yl)-3-arylurea (6a-6e) and 1-(5-bromobenzofuran-2-yl)-3arylurea (6f-6j) have been prepared by reacting5-nitrobenzofuran-2-carbonyl azide 5a or 5-bromobenzofuran-2-carbonyl azide 5b with substituted phenols in reasonable overall yields. Allthe synthesized compounds were characterized using Fourier transform infrared (FTIR), 1H NMR and mass spectrometry and were subjected toantimicrobial screening against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), two Gram-negative bacteria (Escherichiacoli and Pseudomonas aeruginosa), and two fungi (Candida albicans and Aspergillus niger) using two-fold dilution method.Results and Discussion: All the values of FTIR, 1H NMR and mass spectra were found to be prominent. The results indicate that synthesized compound6i showed potent antimicrobial activity comparable to standard.Conclusion: The detailed synthesis, spectroscopic data, and antimicrobial activities of synthesized compounds were reported.Keywords: Benzofuran, Antibacterial activity, Antifungal activity.

Preparation and Biological Activity of New Collagen Composites Part II: Collagen/Reduced Graphene Oxide Composites

: With the idea of exploring the biological activity of some newly synthetized chemical compounds and their combinations for development of novel antimicrobial collagen biomaterials, a serial investigation was initiated, starting with the preparation and biological activity study of Collagen/ZnTiO3 nano-composites. This serial investigation continued with the preparation and biological activity study of new collagen-based composites in which self-prepared reduced graphene oxide (RGO) sheets were included as an antimicrobial agent. The new porous collagen/RGO composites demonstrated specific antimicrobial activity to different types microbial species; well pronounced activity against Gram-positive microorganisms (Listeria innocua and Bacillus cereus, both bacteria with typical chains forming, large size cells, and Candida lusitaniae, fungus with specific micelle organization) and lack of activity against Gram-negative bacteria (Pseudomonas putida, Salmonella enterica, Pseudomonas aeruginosa, and Escherichia coli; all bacteria with small size cells) combined with lack of cytotoxicity to eukaryotic cells. For the first time, well-pronounced antifungal activity of collagen/RGO composites, depending on the RGO concentration was observed. Sterile zone of 17 mm was measured for C. lusitaniae on collagen/RGO composite, 2:1 wt/wt. The possible mechanism of the biological activity of the new collagen/RGO composites was correlated with their characteristics and the specific cell morphology and size of the test microorganisms. The results of this investigation demonstrated that with their specific and adjustable bioactivity, the new collagen/RGO composites are promising antimicrobial biomaterial for variety of biomedical applications, including tissue engineering.

Global Analysis of Type Three Secretion System and Quorum Sensing Inhibition of Pseudomonas savastanoi by Polyphenols Extracts from Vegetable Residues

Protection of plants against bacterial diseases still mainly relies on the use of chemical pesticides, which in Europe correspond essentially to copper-based compounds. However, recently plant diseases control is oriented towards a rational use of molecules and extracts, generally with natural origin, with lower intrinsic toxicity and a reduced negative environmental impact. In this work, polyphenolic extracts from vegetable no food/feed residues of typical Mediterranean crops, as Olea europaea, Cynara scolymus, and Vitis vinifera were obtained and their inhibitory activity on the Type Three Secretion System (TTSS) and the Quorum Sensing (QS) of the Gram-negative phytopathogenic bacterium Pseudomonas savastanoi pv. nerii strain Psn23 was assessed. Extract from green tea (Camellia sinensis) was used as a positive control. Collectively, the data obtained through gfp-promoter fusion system and real-time PCR show that all the polyphenolic extracts here studied have a high inhibitory activity on both the TTSS and QS of Psn23, without any depressing effect on bacterial viability. Extracts from green tea and grape seeds were shown to be the most active. Such activity was confirmed in planta by a strong reduction in the ability of Psn23 to develop hyperplastic galls on explants from adult oleander plants, as well as to elicit hypersensitive response on tobacco. By using a newly developed Congo red assay and an ELISA test, we demonstrated that the TTSS-targeted activity of these polyphenolic extracts also affects the TTSS pilus assembly. In consideration of the potential application of polyphenolic extracts in plant protection, the absence of any toxicity of these polyphenolic compounds was also assessed. A widely and evolutionary conserved molecular target such as Ca2+-ATPase, essential for the survival of any living organism, was used for the toxicity assessment.

(Invited) Mechanisms of Inhibition of Corrosion of Metal Reinforcements for Eco Friendly Concrete Containing a Biological Admixture

The corrosion of steel in concrete is an important phenomenon of degradation of reinforced concrete structures, which starts with the breakdown of the passive layer on steel surface. Reinforcing steel in concrete is usually passivated due to the formation of a protective oxide layer that remains stable in the high alkaline surrounding pore solution. However, carbonation and contamination with chlorides induce passive film breakdown and pitting corrosion initiation. Thus, corrosion inhibitors can be added to fresh concrete as admixtures. A new eco-friendly bio-admixture (BA) produced with extra-cellular substances from a Gram-negative bacteria (Pseudomonas) was tested as inhibitor of corrosion. BA was added at concentration of 10 v/v % to various simulated electrolytes representative of concrete pore solutions (CPS) extracted from different concrete mixtures (CEM I, CEM II and CEM III; w/c = 0.45). The objectives were to study the influence of (1) the chemical composition of CPS and (2) the bio-admixture on the electrochemical behaviour and the surface chemical composition of C15 carbon steel, used for reinforcement of building concrete. Electrochemical measurements: corrosion potential Ecorr as a function of time, polarization curves, electrochemical impedance spectroscopy were performed first in 0.1 M NaOH reference solution to understand the electrochemical behaviour of C15 mild steel by and then compared to those obtained in simulated CPS without or with BA. The pH of the synthetic CPS was adjusted to 13. The electrochemical results were combined to surface reflectivity. Experiments were also carried out in chlorides solution in order to study the effect of BA in localized corrosion conditions. The estimation of the oxide layer thickness using the Cole-Cole approach confirmed the presence of an oxide layer in an extended cathodic potential range in presence of BA.

SYNTHESIS, ANTI-PHYTOPATHOGENIC AND DPPH RADICAL SCAVENGING ACTIVITIES OF C-PRENYLATED ACETOPHENONES AND BENZALDEHYDES

The syntheses of six prenylated acetophenone and benzaldehyde derivatives and their anti-phytopathogenic and antioxidant activities are reported. These com­pounds were obtained by electrophilic aromatic substitution (SEAr) of the corresponding arenes and 3-methyl-2-buten-1-ol using ZnCl2 as a Lewis acid catalyst in ethyl acetate. Reasonable to good yields were obtained based on unrecovered aromatic starting material (45-73%). All the synthesized compounds were evaluated against phytopathogenic gram-negative bacteria Agrobacterium tumefaciens , Pseudomonas syringae and Erwinia carotovora and plant fungal pathogens Botrytis cinerea , Phytophthora cinnamomi and Gibberella fujikuroi . The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scav­enging activity assay and expressed as half maximal inhibitory concentration (IC50) values in μM concentrations. The antioxidant activity went from 27.20 μM to >100 μM. Compound 11 showed statistically significant inhibition of the growth of Botrytis cinerea , and compounds 13 and 15 showed statistically significant inhibition of the growth of Phytophthora cinnamomi , with respect to negative control fungal growth. All six compounds showed bacteriostatic effects against gram-negative plant pathogenic bacteria with IC50 values between 250 and <3.9 μM.

Synthesis, characterization and antibacterial study of cyclometalated rhodium(III) complex containing dithiocarbamate

The novel cyclometalated Rh(III) complex, [Rh(phpy)2(SˆS)], Where phpy is 2-phenylpyridine and (SˆS) is diethyldithiocarbamate, has been prepared and characterized by elemental analysis, IR, 13C and 1H NMR, electronic absorption and Fluorescence spectroscopies, cyclic voltammetry, and X-ray crystallography. The crystal structure of [Rh(phpy)2(SˆS)] shows that the coordination geometry around the Rh(III) is a distorted octahedron, with bite angles of 71.19–81.04° for all three bidentate ligands. Electrochemical analysis by cyclic voltammetry reveals irreversible redox behavior of the rhodium centre. Antibacterial activity of the complex has also been studied by agar disc diffusion method against three Gram-negative bacteria (Pseudomonas aeroginosa, Salmonella typhi and Escherichia coli) and two Gram-positive bacteria (Staphylococcus aureus and Corynebacterium renale).

Clonality of Bacterial Pathogens Causing Hospital-Acquired Pneumonia.

Hospital-acquired pneumonia (HAP) is one of the most serious complications in patients staying in intensive care units. This multicenter study of Czech patients with HAP aimed at assessing the clonality of bacterial pathogens causing the condition. Bacterial isolates were compared using pulsed-field gel electrophoresis. Included in this study were 330 patients hospitalized between May 1, 2013 and December 31, 2014 at departments of anesthesiology and intensive care medicine of four big hospitals in the Czech Republic. A total of 531 bacterial isolates were obtained, of which 267 were classified as etiological agents causing HAP. Similarity or identity was assessed in 231 bacterial isolates most frequently obtained from HAP patients. Over the study period, no significant clonal spread was noted. Most isolates were unique strains, and the included HAP cases may therefore be characterized as mostly endogenous. Yet there were differences in species and potential identical isolates between the participating centers. In three hospitals, Gram-negative bacteria (Enterobacteriaceae and Pseudomonas aeruginosa) prevailed as etiological agents, and Staphylococcus aureus was most prevalent in the fourth center.

Production of the Streptomyces scabies coronafacoyl phytotoxins involves a novel biosynthetic pathway with an F420 -dependent oxidoreductase and a short-chain dehydrogenase/reductase.

Coronafacoyl phytotoxins are secondary metabolites that are produced by various phytopathogenic bacteria, including several pathovars of the Gram-negative bacterium Pseudomonas syringae as well as the Gram-positive potato scab pathogen Streptomyces scabies. The phytotoxins are composed of the polyketide coronafacic acid (CFA) linked via an amide bond to amino acids or amino acid derivatives, and their biosynthesis involves the cfa and cfa-like gene clusters that are found in P. syringae and S. scabies, respectively. The S. scabies cfa-like gene cluster was previously reported to contain several genes that are absent from the P. syringae cfa gene cluster, including one (oxr) encoding a putative F420 -dependent oxidoreductase, and another (sdr) encoding a predicted short-chain dehydrogenase/reductase. Using gene deletion analysis, we demonstrated that both oxr and sdr are required for normal production of the S. scabies coronafacoyl phytotoxins, and structural analysis of metabolites that accumulated in the Δsdr mutant cultures revealed that Sdr is directly involved in the biosynthesis of the CFA moiety. Our results suggest that S. scabies and P. syringae use distinct biosynthetic pathways for producing coronafacoyl phytotoxins, which are important mediators of host-pathogen interactions in various plant pathosystems.

Antibiogram of &amp;lt;i&amp;gt;Escherichia coli&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Pseudomonas&amp;lt;/i&amp;gt; Strains Isolated from Wastewater Generated by an Abattoir as It Journeys into a Receiving River

Untreated wastewater from abattoir operations contains nutrients and other components that aid the growth of microorganisms especially bacteria. They also serve as a habitat for potentially pathogenic bacteria which might be a source of public health concern. The study was carried out to determine the antibiotics susceptibility profile of Gram-negative bacteria (Pseudomonas and Escherichia coli) to selected antibiotics. Wastewater samples were collected from ten different sampling points and cultured on Eosin Methylene Blue (EMB) and King’s B medium. The bacterial strains obtained from the wastewater samples were subjected to antibiotics susceptibility tests, using the disc diffusion technique. A total of 60 Pseudomonas and 100 Escherichia coli were isolated out of which none of the Pseudomonas strains showed resistance to imipenem, colistin sulphate, meropenem and aztreonam, while 100% resistance was observed to ceftazidime and piperacillin. All the Escherichia coli strains were resistant to oxacillin and ceftazidime, while the percentage resistance to aztreonam, ertapenem, cefoxitin and tetracyline was 6%, 11%, 43% and 58% respectively. Eighty-five percent (85%) of the total Escherichia coli showed resistance to more than two antibiotics, while 14% showed resistance to ceftazidime and oxacillin, with only one isolate showing resistance to ceftazidime and cefoxitin. There is the need for an effective treatment of wastewater generated from abattoir operations to prevent the potential spread and transmission of antibiotic resistant bacteria to the human population who depends heavily on some of the water bodies, receiving input from abattoir wastes.

Prevalence of multidrug resistant uropathogenic bacteria in pediatric patients of a tertiary care hospital in eastern India.

Today, because systemic infections such as urinary tract infection (UTI) affect even pediatric patients, antibiotic resistant bacteria have become a constant clinical challenge. In the present study, a total of 1054 urine samples were collected from pediatric patients over 18 months. From these samples, 510 isolates of pathogenic bacteria were collected using HiCrome UTI agar. Antibiotic sensitivity tests of isolates were performed using the Kirby-Bauer method. Two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) and 7 Gram-negative bacteria (Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa) were isolated. Antibiograms of isolated bacteria were ascertained using antibiotics of 4 classes: aminoglycosides, β-lactams, fluoroquinolones and 2 stand-alones (co-trimoxazole and nitrofurantoin). Based on percent values of antibiotic resistance, isolated bacteria were (in decreasing order of number of isolated isolates): E. coli (109)>S. aureus (65)>E. faecalis (82)>E. aerogenes (64)>C. freundii (41)>P. aeruginosa (32)>K. pneumoniae (45)>K. oxytoca (50)>P. vulgaris (22). Surveillance results show that MDR isolates of 9 pathogenic bacteria were prevalent in the environment around the hospital. Thus, revisions to the antimicrobial stewardship program in this area of the country are required to increase clinician confidence in empiric therapy, which is often used for UTI cases.

Antimicrobial activity of Actinomycetale isolated from the lagoon in Algeria

In the aim of the study of the taxonomy and the antimicrobial activity, a strain of actinomycete SM2/2GF which was isolated from sediment of the lagoon El-Mellah which is situated in the city of El-Kala in the Northeast of Algeria, was tested against diverse pathogenic microorganisms and against a Gram-negative bacterium Pseudomonas alcaliphila which was isolated from water of the lagoon El-Mellah. The phenotypic and the molecular characteristics show that the isolate SM2/2GF belongs to the kind Streptomyces. This strain showed an antimicrobial activity against a Gram-negative bacterium Pseudomonas alcaliphila and the positive-Gram bacteria as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Enterococcus faecalis, as well as the yeast Candida albicans. It has no activity against Pseudomonas aeruginosa. The interesting antimicrobial activity of the strain SM2/2GF against the pathogenic microorganisms could encourage further researches on one or several bioactive molecules which it secretes.

Evaluation of Samarium Doped Hydroxyapatite, Ceramics for Medical Application: Antimicrobial Activity

Samarium doped hydroxyapatite (Sm:HAp), (PO4)6(OH)2 (HAp), bionanoparticles with different xSm have been successfully synthesized by coprecipitation method. Detailed characterization of samarium doped hydroxyapatite nanoparticles (Sm:HAp‐NPs) was carried out using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of samarium doped hydroxyapatite was assessed by cell viability. The antibacterial activity of the Sm:HAp‐NPs was tested against Gram‐negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and Gram‐positive bacteria (Enterococcus faecalis and Staphylococcus aureus). A linear increase of antimicrobial activity of P. aeruginosa has been observed when concentrations of Sm:HAp‐NPs in the samples with xSm = 0.02 were higher than 0.125 mg/mL. For Sm:HAp‐NPs with xSm = 0.05 a significant increase of antibacterial activity on E. coli was observed in the range 0.5–1 mg/mL. For low concentrations of Sm:HAp‐NPs (xSm = 0.05) from 0.031 to 0.125 mg/mL a high antibacterial activity on Enterococcus faecalis has been noticed. A growth of the inhibitory effect on S. aureus was observed for all concentrations of Sm:HAp‐NPs with xSm = 0.02.

Bioenergetics and the role of soluble cytochromes C for alkaline adaptation in gram-negative alkaliphilic Pseudomonas.

Very few studies have been conducted on alkaline adaptation of Gram-negative alkaliphiles. The reversed difference of H+ concentration across the membrane will make energy production considerably difficult for Gram-negative as well as Gram-positive bacteria. Cells of the alkaliphilic Gram-negative bacterium Pseudomonas alcaliphila AL15-21T grown at pH 10 under low-aeration intensity have a soluble cytochrome c content that is 3.6-fold higher than that of the cells grown at pH 7 under high-aeration intensity. Cytochrome c-552 content was higher (64% in all soluble cytochromes c) than those of cytochrome c-554 and cytochrome c-551. In the cytochrome c-552-dificient mutant grown at pH 10 under low-aeration intensity showed a marked decrease in μ max⁡ [h−1] (40%) and maximum cell turbidity (25%) relative to those of the wild type. Considering the high electron-retaining abilities of the three soluble cytochromes c, the deteriorations in the growth of the cytochrome c-552-deficient mutant could be caused by the soluble cytochromes c acting as electron storages in the periplasmic space of the bacterium. These electron-retaining cytochromes c may play a role as electron and H+ condenser, which facilitate terminal oxidation at high pH under air-limited conditions, which is difficult to respire owing to less oxygen and less H+.

Activation of formation of bacterial biofilms by azithromycin and prevention of this effect

Growth of members of most of the studied genera of gram-positive (Dietzia, Kocuria, and Rhodo- coccus) and gram-negative bacteria (Pseudomonas and Chromobacterium) in biofilms exhibited higher resistance to an translation inhibitor, azithromycin compared to the growth of planktonic cultures of the same strains. Low concentrations of azithromycin were found to stimulate biofilm formation by the studied saprotrophic strains. The rate of synthesis of the polysaccharide matrix component exceeded the rate of cell growth, indicating implementation of the biofilm phenotype under these conditions. It was found that an alkylhydroxybenzene (AHB) compound 4-hexylresorcinol was capable of almost uniform suppression of growth of both planktonic cultures and biofilms of the saprotrophic strains under study. In some cases, combined action ofazithromycin and AHB resulted in an additive inhibitory effect and prevented the stimulation of biofilm growth by subinhibitory azithromycin concentrations. Thus, AHB may be considered a promising antibiofilm agent.

Growth ability of Gram negative bacteria in free-living amoebae

When bacteria and free-living amoebae (FLAs) live both in natural waters and man-made aquatic systems, they constantly interact with each other. Some bacteria can survive and grow within FLAs. Therefore, it has recently been thought that FLAs play an important role in spreading pathogenic bacteria in aquatic systems. In this study we investigated the intracellular growing ability of 7 different Gram-negative bacteria (Pseudomonas fluorescens, Pseudomonas putida, Pasteurella pneumotropica, Aeromonas salmonicida, Legionella pneumophila serogroup 1, L. pneumophila serogroup 3, L. pneumophila serogroup 6) in four different FLA isolates (A1–A4). Among these, four bacterial isolates (P. fluorescens, P.putida, P.pneumotropica, A.salmonicida) and two free-living amoebae isolates (A3, A4) were isolated from the tap water in our city (Istanbul). It was found that 4 different Gram-negative bacteria could grow in A1, 2 different Gram-negative bacteria could grow in A2, 4 different Gram-negative bacteria could grow in A3, 1 Gram-negative bacterium could grow in A4. In conclusion, we think that this ability of growth could vary according to the characteristics of both bacteria and FLA isolates. Also, other factors such as environmental temperature, bacterial concentration, and extended incubation period may play a role in these interactions. This situation can be clarified with future studies.

Identification of coagulase-negative staphylococci in daily disposable contact lens wearers.

This study aimed to identify and quantify the number of contaminating organisms on daily disposable (DD) soft contact lenses, which may be responsible for mild cases of keratitis that occur with this lens wear modality. Ten participants wore DD lenses, and 10 participants wore planned replacement (PR) lenses. Lenses were collected aseptically and analysed for microbial contamination. Colony-forming units (CFU) were recorded, and representative colonies were used for identification using the API identification system. The DD lenses evaluated in this study were contaminated with coagulase-negative staphylococcus (CNS), ranging from 1 to 653 CFU. PR lenses showed more diversity in the types of contaminating micro-organisms and consisted of CNS, Gram-negative bacteria (Pseudomonas), a yeast (Candida) and a mould (Aspergillus), ranging from 1 to 230 CFU. CNS was the only type of micro-organism found on DD contact lenses and therefore may be the cause of any form of keratitis observed in DD lens wearers. This is the first study to determine the frequency and identify the contaminating organisms found on daily disposable (DD) soft contact lenses. The contaminating organisms identified on DD contact lenses were solely coagulase-negative staphylococcus (CNS), suggesting that CNS may be the causative organism associated with infectious keratitis that occurs with DD contact lens wear.

Toxicity of differently sized and coated silver nanoparticles to the bacterium Pseudomonas putida: risks for the aquatic environment?

Aim of this study was to describe the toxicity of a set of different commercially available silver nanoparticles (AgNPs) to the gram-negative bacterium Pseudomonas putida (growth inhibition assay, ISO 10712) in order to contribute to their environmental hazard and risk assessment. Different AgNP sizes and coatings were selected in order to analyze whether those characteristics are determinants of nanoparticle toxicity. Silver nitrate was tested for comparison. In general Pseudomonas putida reacted very sensitive towards the exposure to silver, with an EC05 value of 0.043 μg L−1 for AgNO3 and between 0.13 and 3.41 μg L−1 for the different AgNPs (EC50 values 0.16 μg L−1 for AgNO3, resp. between 0.25 and 13.4 μg L−1 for AgNPs). As the ionic form of silver is clearly the most toxic, an environmental hazard assessment for microorganisms based on total silver concentration and the assumption that AgNPs dissolve is sufficiently protective. Neither specific coatings nor certain sizes could be linked to increasing or decreasing toxicity. The characterization of particle behavior as well as the total and dissolved silver content in the medium during the exposures was not possible due to the high sensitivity of Pseudomonas (test concentrations were below detection limits), indicating the need for further development in the analytical domain. Monitored silver concentrations in the aquatic environment span six orders of magnitude (0.1–120,000 ng L−1), which falls into the span of observed EC05 values and might hence indicate a risk to environmental bacteria.

Synthesis and Antimicrobial Activities of Novel Aminoalkylated 2H-benzotriazoles

In view of generating new compounds for future drug development, we have synthesized some N-aminoalkylated derivatives of benzo[d][1,2,3]triazole by alkylating benzo[d][1,2,3]triazole in the presence of K2CO3/DMF using 1,6-dibromohexane to obtain the 2-(6-bromohexyl)-2H-benzo[d][1,2,3]triazole (3) as the one of the major product which was then used as an intermediate to synthesize a new series of compounds 4a-j. All the synthesized compounds were fully characterized on the basis of their detailed spectral studies and were evaluated for their antimicrobial activities In vitro against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermis), four Gram-negative bacteria (Echerichia coli, Pseudomonas aeuroginosa, Staphylococcus typhi and Klebsiella pneumoniae) and four fungi (Aspergillus niger, Aspergillus fumigatus, Candida albicans and Aspergillus flavus) strains using Cup plate method.