Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).
We report on the cloning of the lipase gene from Bacillus licheniformis IBRLCHS2
and the expression of the recombinant lipase. DNA sequencing analysis of the
cloned lipase gene showed that it shares 99% identity with the lipase gene from
B. licheniformis ATCC 14580 and belongs to subfamily 1.4 of true lipases based on amino
acid sequence alignment of various Bacillus lipases. The 612 bp lipase gene was then
cloned into the pET-15b(+) expression vector and the construct was transformed into
E. coli BL21 (DE3) for bulk expression of the lipase. Expression was analysed by SDSPAGE
where the lipase was found to have a molecular weight of about 23 kDa.
Hymenocallis littoralis (Jacq.) Salisb (Melong kecil) commonly known as 'Spider Lily' is an herbaceous plant from the family Amaryllidaceae. Study was carried out to determine the effect of H. littoralis leaf extract on the growth and morphogenesis of two pathogenic microbes, Candida albicans and Escherichia coli. The leaf extract displayed favourable anticandidal and antibacterial activity with a minimum inhibition concentration (MIC) of 6.25 mg/mL. Time kill study showed both microbes were completely killed after treated with leaf extract at 20 h. Both microbes' cell walls were heavily ruptured based on scanning electron microscopy (SEM) analysis. The significant anticandidal and antibacterial activities showed by H. littoralis leaf extract suggested the potential antimicrobial agent against C. albicans and E. coli.
Nanotechnology is drawing attention nowadays due to its ability to regulate metals into nanosize, ultimately changing metal's physical, chemical, and optical properties. Silver nanoparticles are known for their potential impact as antimicrobial agents due to their inherent property penetrating the cell wall. The present study aimed to develop and statistically optimise using a novel combination of capsaicin loaded silver nanoparticles (AgCNPs) as an effective anti-bacterial agent to treat psoriasis using a green approach. Ascorbic acid was used as a reducing agent to fabricate silver nanoparticles. The formulation parameters optimisation was conducted using Box-Behnken Design (3×3 factorial design). The loading of capsaicin was confirmed by attenuated total reflectance-fourier transform infrared spectroscopy. Energy-dispersive X-ray spectroscopy-scanning electron microscopy (EDX-SEM) confirmed the existence of silver; net-like structure revealed in SEM and high-resolution transmission electron microscopy further confirmed the nano size of the formulation. Differential scanning calorimetry and X-ray diffraction demonstrated the capsaicin transformed into amorphous after encapsulated. An in-vitro microbial study showed that the 0.10 M formulation of AgCNPs exerted potent anti-bacterial activity, which can be considered an alternative anti-bacterial agent. It also displayed that the zone of inhibition was significantly high in gram-negative bacteria (E. coli) than gram-positive bacteria (S. aureus). Green synthesised AgCNPs showed highly significant anti-bacterial activity, which indicates that this formulation can be very promising for treating psoriasis.
An awareness of Escherichia coli as a foodborne pathogen and illness causing bacterium has been increased among consumers. Moreover, there is demand for natural product in order to reduce synthetic product that can cause toxic to the human. In this study, antibacterial activity, in term of MIC, MBC and killing-time curve of methanolic extract of Boesenbergia rotunda have been tested against a standard E. coli ATCC 25922 and two E. coli isolated from milk products using Clinical and Laboratory Standard Institute (CLSI) methods. The results show that B. rotunda extract was susceptible to all E. coli strains. The MIC and MBC values of B. rotunda extract against E. coli ranged 0.019 mg/mL 2.5 mg/mL and 0.039 mg/mL – 5.0 µg/mL, respectively. Killing-time curves were constructed at concentrations of 0x MIC, 1/2x MIC, 1x MIC, and 2x MIC. All E. coli strains can be killed with concentration of 2x MIC after 2 hours. The results show that B. rotunda extract has potential antibacterial activity against E. coli.
Synthesis of 2,5-bisarylthiophenes was accomplished by sequential Suzuki cross coupling reaction of 2-bromo-5-chloro thiophenes. Density functional theory (DFT) studies were carried out at the B3LYP/6-31G(d, p) level of theory to compare the geometric parameters of 2,5-bisarylthiophenes with those from X-ray diffraction results. The synthesized compounds are screened for in vitro bacteria scavenging abilities. At the concentration of 50 and 100 μg/mL, compounds 2b, 2c, 2d, 3c, and 3f with IC50-values of 51.4, 52.10, 58.0, 56.2, and 56.5 μg/mL respectively, were found most potent against E. coli. Among all the synthesized compounds 2a, 2d, 3c, and 3e with the least values of IC50 77, 76.26, 79.13 μg/mL respectively showed significant antioxidant activities. Almost all of the compounds showed good antibacterial activity against Escherichia coli, whereas 2-chloro-5-(4-methoxyphenyl) thiophene (2b) was found most active among all synthesized compound with an IC50 value of 51.4 μg/mL. All of the synthesized compounds were screened for nitric oxide scavenging activity as well. Frontier molecular orbitals (FMOs) and molecular electrostatic potentials of the target compounds were also studied theoretically to account for their relative reactivity.
The main source of E. coli 0157:H7 is cattle, but recent studies showed high percentage of outbreaks
contributed by contaminated water. The occurrence of E. coli O157:H7 in environmental water samples poses a potential threat to human health. The aim of this study was to establish a protocol for the detection of the pathogen E. coli O157:H7 and E. coli virulence genes (eaeA, rfbE, hly, stx1, and stx2) in a multiplex PCR protocol using six specific primer pairs. The target genes produced species-specific amplicons at 625 bp, 397 bp, 296 bp, 166 bp, 210 bp and 484 bp for E. coli O157:H7 (fliCh7 gene) and virulence genes (eaeA, rfbE, hly, stx1, and stx2) respectively. The results obtained show that the established PCR protocol is suitable for a rapid and specific analysis of the pathogenic E. coli O157:H7 in environmental water samples for the assessment of microbiological risks.
The effects of methanolic extract of Javanese turmeric (Curcuma xanthorrhiza Roxb.) at different level of concentrations on the inactivation of Bacillus cereus, Escherichia coli, Pseudomonas spp. and Staphylococcus aureus in oyster mushroom (Pleurotus sajor-caju) were investigated. This study was conducted principally for the achievement on the best combination between the
susceptibility of C. xanthorrhiza extract on natural microflora and foodborne pathogenic bacteria with the sensory acceptability of the soaked oyster mushroom. Three different concentrations (g/ml), 0.05%, 0.50% and 5.00%, of C. xanthorrhiza extract prepared with dilution method were designed as sanitizing agent in treating the oyster mushroom at 5 minutes and 10 minutes.
There was significance reduction in the survival of microbial load between the untreated fresh oyster mushroom and those soaked with 0.05%, 0.50% and 5.00% rhizome extract (P
Unprocessed ‘budu’ is a mixture of anchovies and salt that has been fermented for a period of time, and has not been heat-treated nor formulated with additional ingredients. This study analyzed Malaysian
unprocessed ‘budu’ from 12 producers for microbiological, salt, protein, histamine and 3-MCPD contents.
The results demonstrated that Malaysian unprocessed ‘budu’ were free from pathogenic Coliform, E. coli,
V. parahaemolyticus and V. cholerae contaminations. Carcinogenic 3-MCPD was below detection level of 2 ppb for all 12 samples tested. However, 58% of the unprocessed ‘budu’ had histamine content greater than the hazardous levels of 50 mg/100 g sample.
Acanthamoeba keratitis is a serious ocular problem and can cause blindness if not treated. This study was therefore performed to evaluate the effectiveness of eyedrop antibiotics on eight Acanthamoeba spp. isolates, of which four
were clinical isolates and the remaining four from the environment. Three different eyedrop antibiotics (neomycin, ciprofloxacin and gentamicin) currently available in the market and ready for use were tested. Cyst suspension from all strains were tested against eyedrop antibiotics, respectively. After 48 hours of incubation period, the solutions were filtered and the filtered membranes were put onto non-nutrient agar lawn with E. coli. The plates were examined daily for Acanthamoeba trophozoites under inverted microscope until day 14. Neomycin, ciprofloxacin and gentamicin were found
to be effective against Acanthamoeba spp. cysts for all test strains.
Key words: Acanthamoeba Keratitis, Eyedrop Antibiotics, Effectiveness
Keratitis Acanthamoeba merupakan sejenis inflamasi kornea yang dikaitkan dengan penggunaan kanta sentuh. la disebabkan oleh Acanthamoeba spp., ameba hidup bebas yang tersebar luas di pelbagai persekitaran manusia. Kontaminasi Acanthamoeba spp. pada bekas penyimpanan kanta sentuh merupakan faktor kehadiran ameba pada kanta seterusnya menjangkiti mata. Kajian ini bertujuan untuk melihat kehadiran Acanthamoeba spp. pada bekas penyimpanan kanta sentuh pengguna asimptomatik. Seramai 90 orang pengguna kanta sentuh asimptomatik terlibat dalam kajian ini. Sampel diambil secara swab pada bekas kanta sentuh dan dikulturkan ke atas agar bukan nutrien yang dilapisi Escherichia coli. Plat agar diperiksa setiap hart bagi mengesan kehadiran ameba. Kultur positif seterusnya disahkan di bawah 'Image Analysis with Video TesT 4.0'. Acanthamoeba spp. didapati positif pada lapan daripada 90 sampel (8. 7%) dan kesemua strain adalah kumpulan II (polyphagids). Penemuan ini membuktikan Acanthamoeba spp. boleh Nadir pada bekas penyimpanan kanta sentuh pengguna asimptomatik dan boleh menjadi risiko jangkitan keratitis Acanthamoeba.
Surfactants are multifunctional molecules widely used in personal care and healthcare formulations to cleanse, help disperse active ingredients (e.g., forming emulsions) and stabilise products. With increasing demands on improving biosafety, there is now mounting pressure to understand how different surfactants elicit toxicities at molecular and cellular levels. This work reports the membrane-lytic behaviour of a group of sulphonated methyl ester (SME) surfactants together with representative conventional surfactants. All surfactants displayed the clear rise of lysis of the model lipid bilayer membranes around their CMCs, but the two ionic surfactants SDS and C12TAB even caused measurable lysis below their CMCs, with membrane-lytic actions increasing with monomer concentration. Furthermore, whilst ionic and nonionic surfactants could achieve full membrane lysis once above their CMCs, this ability was weak from the SME surfactants and decreased with increasing the acyl chain length. In contrast to the conventional anionic surfactants such as SDS and SLES, the protein solubilizing capability of the SME surfactants was also low. On the other hand, MTT assays against 3T3 fibroblast cells and human chondrocyte cells revealed high toxicity from SDS and C12TAB against the other surfactants studied, but the difference between SME and the rest of conventional surfactants was small. Similar behaviour was also observed in their bactericidal effect against E. coli and S. aureus. The trend is broadly consistent with their membrane-lytic behaviour, indicating little selectivity in their cytotoxicity and bactericidal action. These results thus reveal different toxicities implicated from different surfactant head groups. Increase in acyl chain length as observed from SME surfactants could help improve surfactant biocompatibility.
The process of intercellular communication among bacteria, termed quorum sensing (QS), is mediated by small diffusible molecules known as the autoinducers. QS allows the population to react to the change of cell density in unison, in processes such as biofilm formation, plasmid conjugation, virulence, motility and root nodulation. In Gram-negative proteobacteria, N-acyl homoserine lactone (AHL) is the common "language" to coordinate gene expression. This signaling molecule is usually synthesized by LuxI-type proteins. We have previously discovered that a rare bacterium, Cedecea neteri, exhibits AHL-type QS activity. With information generated from genome sequencing, we have identified the luxIR gene pair responsible for AHL-type QS and named it cneIR. In this study, we have cloned and expressed the 636 bp luxI homolog in an Escherichia coli host for further characterization. Our findings show that E. coli harboring cneI produced the same AHL profile as the wild type C. neteri, with the synthesis of AHL known as N-butyryl-homoserine lactone. This 25 kDa LuxI homolog shares high similarity with other AHL synthases from closely related species. This work is the first documentation of molecular cloning and characterization of luxI homolog from C. neteri.
Pseudogenes in the Escherichia coli genome are assumed to be non-functional. In this study, Keio collection BW25113∆yqiG and YqiG-producing strain (BW25113/pCA24N-YqiG) were used to evaluate the importance of pseudogene yqiG in hydrogen metabolism. Our results show pseudogene protein YqiG was identified as an essential protein in the production of biohydrogen from glucose. The mutant yqiG decreased biohydrogen production from 37 µmol mg-1 protein to 6 µmol mg-1 protein compared to the wild-type strain, and glucose consumption was reduced by 80%. Through transcriptional analysis, we found that the yqiG mutation represses pflB transcription tenfold; pflB encodes pyruvate-formate lyase, one of the key enzymes in the anaerobic metabolism of E. coli. Moreover, production of YqiG stimulated glycolysis and increased biohydrogen productivity 1.5-fold compared to that of the wild-type strain. Thus, YqiG is important for the central glycolysis reaction and is able to influence hydrogen metabolism activity in E. coli.
Foodborne illness is a global burden that impacts a country politically, economically and
socio-economically. The severity of the burden can be unmeasurable as foodborne illness
is often an underestimated problem. In order to enlighten the burden, appropriate food
safety control measures should be taken. This study aimed to optimize a multiplex
Polymerase Chain Reaction (mPCR) detection method to identify foodborne pathogens
simultaneously. Six foodborne pathogens namely, Salmonella spp., Escherichia coli O157,
Vibrio parahaemolyticus, Vibrio cholerae, Listeria monocytogenes and Campylobacter
spp., were targeted in the mPCR detection method. Each mPCR parameter was tested and
the outcome was analysed to obtain a successful mPCR protocol to detect the targeted
foodborne pathogens. The amplified PCR products showed that the optimized mPCR
protocol will be a potential rapid diagnostic tool in foodborne pathogen detection.
Recently, epidermal mucus of fish has been identified as a rich biological source of various bioactive substances, particularly antibacterial peptides. This study was conducted to identify the potential of epidermal mucosa of Clarias batrachus as a source of antibacterial material. Mucosal samples were collected from C. batrachus epidermis and extracted using an aqueous extraction method. Antibacterial activity of the crude epidermal mucus extract was determined by using spectrophotometric method. As a result there was antibacterial activity by the mucus extract against Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). The results of this study supports the role of mucus as a part of body immune system with antibacterial peptide as a component of innate body immune system. Hence, these findings can be used as one of the first steps towards the development of new class antibiotics.
Titanium dioxide nanoparticles were synthesized by using sol gel method and their physico-chemical properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectrophotometer. The photocatalytic property of TiO2 nanoparticles was investigated by inactivation of Escherichia coli under irradiation of fluorescent lamp. The results showed that the size of TiO2 was in the range of 3 to 7 nm with high crystallinity of anatase phase. The sharp peaks in FTIR spectrum determined the purity of TiO2 nanoparticles and absorbance peak of UV-Vis spectrum showed the energy band gap of 3.2 eV. Optimum inactivation of E. coli was obtained at 1.0 g/L TiO2 nanoparticles, with 80% of E. coli population was inactivated. The light scattering effect and insufficient concentration are the factors that cause the less effective inactivation reaction for 2.5 g/L and 0.1 g/L TiO2 concentration.
The presence of coliforms bacteria is one of the most prevalent problems in terms of public health in marine ecosystems over the world. In this study were investigated the physico-chemical properties of seawater and the numbers of total aerobic, total coliform, fecal coliform, E. coli O157:H7 and fecal streptococci in seawater and mussel samples collected from Sinop environs between May and October 2011. The microbiological analysis of seawater samples showed that the difference between total coliform, fecal coliform and fecal streptococci numbers (p<0.05) was significant for each station. However, the difference among total aerobic bacteria numbers for each stations (p>0.05) were not found significant. The difference between whole counting results for mussel samples taken from different sampling sites was not significant (p>0.05), too. Furthermore, the results of the screening assay for the presence of E. coli O157:H7 showed that the strain was not detected in neither seawater nor mussel samples. In conclusion, it was determined that fecal coliform and fecal streptococci counts in the seawater and mussel samples were higher than legal (Turkish Bathing Water and Quality of Fishery Products Regulation) limit values for some stations in Sinop coastal areas.
Staphylococcus sp. as Gram-positive and Escherichia coli as Gram-negative are bacterial pathogens and can cause primary bloodstream infections and food poisoning. Coagulation, flocculation, and sedimentation processes could be a reliable treatment for bacterial removal because suspended, colloidal, and soluble particles can be removed. Chemical coagulants, such as alum, are commonly used. However, these chemical coagulants are not environmentally friendly. This present study evaluated the effectiveness of coagulation, flocculation, and sedimentation processes for removing Staphylococcus sp. and E. coli using diatomite with standard jar test equipment at different pH values. Staphylococcus sp. demonstrated 85.61% and 77.23% significant removal in diatomite and alum, respectively, at pH 5. At pH 7, the removal efficiency decreased to 79.41% and 64.13% for Staphylococcus sp. and E. coli, respectively. At pH 9, there was a decrease in Staphylococcus sp. after adding diatomite or alum compared with that of E. coli. The different removal efficiencies of the Gram-positive and Gram-negative bacteria could be owing to the membrane composition and different structures in the bacteria. This study indicates that diatomite has higher efficiency in removing bacteria at pH 5 and can be considered as a potential coagulant to replace alum for removing bacteria by the coagulation process.
Nanomaterials can be incorporated in the synthesis of membrane to obtain mixed-matrix membrane with marked improvement in properties and performance. However, stability and dispersion of the nanomaterials in the membrane matrix, as well as the need to use high ratio of nanomaterials for obvious improvement of membrane properties, remain a major hurdle for commercialization. Hence, this study aims to investigate the improvement of polyamide 6,6 membrane properties with the incorporation of silver nanoparticles decorated on graphene oxide (Ag-GO) nanoplates and at the same time focus is given to the issues above. Graphene oxide nanoplates were synthesized using the modified Hummers' method and decorated with silver before embedded into the polyamide 6,6 matrix. Physicochemical characterizations were conducted on both nanoplates and the mixed-matrix Ag-GO polyamide 6,6 membrane. The issues of Ag agglomeration and leaching were not observed, which could be attributed to the decoration of Ag on GO that helped to disperse the nanomaterials and provided a better anchor point for the attachment of Ag nanoparticles. The synthesized membrane showed marked improvement regarding flux (135% increment) and antifouling (40% lower irreversible fouling), which could be ascribed to the more negative charge of membrane surface (-14 ± 6 to -31 ± 3.8 mV) and hydrophilicity (46% enhancement) of the membranes. With minimal embedment of Ag nanoparticles, the membrane showed superior antibacterial property where the E. coli bacteria could not form a single colony on the membrane surface. Overall, the decoration of Ag on GO nanoplates could be a promising approach to resolve the agglomeration and leaching issues as well as reduce the amount of precious Ag in the synthesis of Ag-GO polyamide 6,6 membrane.