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Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase

Baerson SR, Rodriguez DJ, Tran M, Feng Y, Biest NA, Dill GM

Plant Physiol, 2002 Jul;129(3):1265-75.
PMID: 12114580

The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species.

Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/genetics; Escherichia coli/growth & development
Fulltext In Vitro Pharmacological Activities and GC-MS Analysis of Different Solvent Extracts of Lantana camara Leaves Collected from Tropical Region of Malaysia

Swamy MK, Sinniah UR, Akhtar MS

Evid Based Complement Alternat Med, 2015;2015:506413.
PMID: 26783409 DOI: 10.1155/2015/506413

We investigated the effect of different solvents (ethyl acetate, methanol, acetone, and chloroform) on the extraction of phytoconstituents from Lantana camara leaves and their antioxidant and antibacterial activities. Further, GC-MS analysis was carried out to identify the bioactive chemical constituents occurring in the active extract. The results revealed the presence of various phytocompounds in the extracts. The methanol solvent recovered higher extractable compounds (14.4% of yield) and contained the highest phenolic (92.8 mg GAE/g) and flavonoid (26.5 mg RE/g) content. DPPH radical scavenging assay showed the IC50 value of 165, 200, 245, and 440 μg/mL for methanol, ethyl acetate, acetone, and chloroform extracts, respectively. The hydroxyl scavenging activity test showed the IC50 value of 110, 240, 300, and 510 μg/mL for methanol, ethyl acetate, acetone, and chloroform extracts, respectively. Gram negative bacterial pathogens (E. coli and K. pneumoniae) were more susceptible to all extracts compared to Gram positive bacteria (M. luteus, B. subtilis, and S. aureus). Methanol extract had the highest inhibition activity against all the tested microbes. Moreover, methanolic extract of L. camara contained 32 bioactive components as revealed by GC-MS study. The identified major compounds included hexadecanoic acid (5.197%), phytol (4.528%), caryophyllene oxide (4.605%), and 9,12,15-octadecatrienoic acid, methyl ester, (Z,Z,Z)- (3.751%).

Matched MeSH terms: Escherichia coli
Fulltext GC-MS Based Metabolite Profiling, Antioxidant and Antimicrobial Properties of Different Solvent Extracts of Malaysian Plectranthus amboinicus Leaves

Swamy MK, Arumugam G, Kaur R, Ghasemzadeh A, Yusoff MM, Sinniah UR

Evid Based Complement Alternat Med, 2017;2017:1517683.
PMID: 28424737 DOI: 10.1155/2017/1517683

This study evaluates the phytochemistry, antioxidant, and antimicrobial effects of Plectranthus amboinicus leaves extracted in different solvents. The methanol extract contained the highest total phenolic (94.37 ± 1.24 mg GAE/g) and flavonoid contents (26.90 ± 1.35 mg RE/g) and exhibited the highest DPPH scavenging activity (90.13 ± 3.32%) followed by the acetone extract (80.23 ± 3.26%) at 500 μg/mL concentration. Similarly, the highest ferric ion reduction potential (849.63 ± 30.95 μM of Fe (II)/g dry weight) was exhibited by the methanol extract followed by the acetone extract (695.92 ± 25.44 μM of Fe (II)/g dry weight). The methanol extract showed greater antimicrobial activity against all the tested pathogens (Bacillus subtilis, Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans). However, both hexane and acetone extracts failed to inhibit E. coli. S. aureus and C. albicans were more susceptible to all the extracts. Further, GC-MS analysis confirmed the occurrence of a total 46 phytocompounds in different solvent extracts. Some of the major compounds included carvacrol (37.7%), tetracontane (16.6%), squalene (15.6%), tetrapentacontane (13.7%), and Phytol (12.9%). In conclusion, extraction solvents influenced the recovery of phytocompounds and the highest pharmacological activities of the methanol extract could be correlated to the presence of additional bioactive compounds.

Matched MeSH terms: Escherichia coli
Fulltext Effects of Flower and Fruit Extracts of Melastoma malabathricum Linn. on Growth of Pathogenic Bacteria: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium

Che Omar SN, Ong Abdullah J, Khairoji KA, Chin Chin S, Hamid M

Evid Based Complement Alternat Med, 2013;2013:459089.
PMID: 23662136 DOI: 10.1155/2013/459089

Melastoma malabathricum Linn. is a shrub that comes with beautiful pink or purple flowers and has berries-like fruits rich in anthocyanins. This study was carried out with the aim to evaluate the inhibitory activities of different concentrations of the M. malabathricum Linn. flower and fruit crude extracts against Listeria monocytogenes IMR L55, Staphylococcus aureus IMR S244, Escherichia coli IMR E30, and Salmonella typhimurium IMR S100 using the disc diffusion method. The lowest concentrations of the extracts producing inhibition zones against the test microorganisms were used to determine their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). In addition, the growth of Listeria monocytogenes IMR L55 and Staphylococcus aureus IMR S244 grown in medium supplemented with the respective extracts at different temperatures (4°C, 25°C, and 37°C) and pHs (4, 6, 7, and 8) was determined.

Matched MeSH terms: Escherichia coli
Fulltext Chemical Composition, Antioxidant, Antibacterial, and Antibiofilm Activities of Backhousia citriodora Essential Oil

Lim AC, Tang SGH, Zin NM, Maisarah AM, Ariffin IA, Ker PJ, et al.

Molecules, 2022 Jul 31;27(15).
PMID: 35956846 DOI: 10.3390/molecules27154895

The essential oil of Backhousia citriodora, commonly known as lemon myrtle oil, possesses various beneficial properties due to its richness in bioactive compounds. This study aimed to characterize the chemical profile of the essential oil isolated from leaves of Backhousia citriodora (BCEO) and its biological properties, including antioxidant, antibacterial, and antibiofilm activities. Using gas chromatography-mass spectrometry, 21 compounds were identified in BCEO, representing 98.50% of the total oil content. The isomers of citral, geranial (52.13%), and neral (37.65%) were detected as the main constituents. The evaluation of DPPH radical scavenging activity and ferric reducing antioxidant power showed that BCEO exhibited strong antioxidant activity at IC50 of 42.57 μg/mL and EC50 of 20.03 μg/mL, respectively. The antibacterial activity results showed that BCEO exhibited stronger antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) than against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae). For the agar disk diffusion method, S. epidermidis was the most sensitive to BCEO with an inhibition zone diameter of 50.17 mm, followed by S. aureus (31.13 mm), E. coli (20.33 mm), and K. pneumoniae (12.67 mm). The results from the microdilution method showed that BCEO exhibited the highest activity against S. epidermidis and S. aureus, with the minimal inhibitory concentration (MIC) value of 6.25 μL/mL. BCEO acts as a potent antibiofilm agent with dual actions, inhibiting (85.10% to 96.44%) and eradicating (70.92% to 90.73%) of the biofilms formed by the four tested bacteria strains, compared with streptomycin (biofilm inhibition, 67.65% to 94.29% and biofilm eradication, 49.97% to 89.73%). This study highlights that BCEO can potentially be a natural antioxidant agent, antibacterial agent, and antibiofilm agent that could be applied in the pharmaceutical and food industries. To the best of the authors' knowledge, this is the first report, on the antibiofilm activity of BCEO against four common nosocomial pathogens.

Matched MeSH terms: Escherichia coli
The Effects of Bacillus subtilis QST713 and β-mannanase on growth performance, intestinal barrier function, and the gut microbiota in weaned piglets

Liu J, Ma X, Zhuo Y, Xu S, Hua L, Li J, et al.

J Anim Sci, 2023 Jan 03;101.
PMID: 37583344 DOI: 10.1093/jas/skad257

We investigated the effects of different Bacillus subtilis QST713 doses and a B. subtilis QST713 and β-mannanase mix on growth performance, intestinal barrier function, and gut microbiota in weaned piglets. In total, 320 healthy piglets were randomly assigned to four groups: 1) control group (basal diet), 2) BS100 group (basal diet plus 100 mg/kg B. subtilis QST713), 3) BS200 group (basal diet plus 200 mg/kg B. subtilis QST713), and 4) a BS100XT group (basal diet plus 100 mg/kg B. subtilis QST713 and 150 mg/kg β-mannanase). The study duration was 42 d. We showed that feed intake in weaned piglets on days 1 to 21 was increased in group BS100 (P < 0.05), and that the feed conversion ratio in group BS100XT animals decreased throughout the study (P < 0.05). In terms of microbial counts, the BS100XT group showed reduced Escherichia coli and Clostridium perfringens numbers on day 21 (P < 0.05). Moreover, no significant α-diversity differences were observed across all groups during the study (P > 0.05). However, principal coordinates analysis indicated clear separations in bacterial community structures across groups (analysis of similarities: P < 0.05) on days 21 and 42. Additionally, E-cadherin, occludin, and zonula occludens-1 (ZO-1) expression in piglet feces increased (P < 0.05) by adding B. subtilis QST713 and β-mannanase to diets. Notably, this addition decreased short-chain fatty acid concentrations. In conclusion, B. subtilis QST713 addition or combined B. subtilis QST713 plus β-mannanase effectively improved growth performance, intestinal barrier function, and microbial balance in weaned piglets.

Matched MeSH terms: Escherichia coli
Antimicrobial activity of essential oils of Curcuma longa and Syzygium aromaticum against multiple drug-resistant pathogenic bacteria

Zeshan MQ, Ashraf M, Omer MO, Anjum AA, Ali MA, Najeeb M, et al.

Trop Biomed, 2023 Jun 01;40(2):174-182.
PMID: 37650404 DOI: 10.47665/tb.40.2.008

The present study was conducted to investigate the antimicrobial potential of essential oils of Curcuma longa and Syzygium aromaticum against multidrug-resistant pathogenic bacteria. Four identified bacterial isolates including Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii were selected and their antibiotic sensitivity was checked by disc diffusion assay. C. longa and S. aromaticum were subjected to steam distillation to obtain their essential oils. The crude essential oils were fractioned by employing column chromatography. Crude essential oils and their fractions were evaluated for their antibacterial activity by agar well diffusion assay and minimum inhibitory concentrations were calculated. All the selected bacterial isolates showed resistance to three or more than three antibiotic groups and were declared as multidrugresistant (MDRs). Crude essential oils of C. longa and S. aromaticum exhibited antimicrobial activity against all selected isolates but S. aromaticum activity was better than the C. longa with a maximum 19.3±1.50 mm zone of inhibition against A. baumannii at 1.04 µL/mL MIC. GC/MS analysis revealed the abundance of components including eugenol, eugenyl acetate, b- caryophyllene, and a- Humulene in both crude oil and fractions of S. aromaticum. While the main components of C. longa essential oil were Ar-tumerone, a-tumerone, b- Tumerone, I-Phellandrene, a-zingibirene, b- sesquiphellandrene, and p- Cymene. This study highlights that plant-based essential oils could be a promising alternative to antibiotics for which pathogens have developed resistance. C. longa and S. aromaticum carry compounds that have antimicrobial potential against multiple drug-resistant bacteria including MRSA. E. coli, K. pneumoniae and A. baumannii.

Matched MeSH terms: Escherichia coli
Green synthesis, characterisation and antibacterial activities of Strobilanthes crispus-mediated silver nanoparticles (SC-AGNPS) against selected bacteria

Mohamad Hanafiah R, Abd Ghafar SA, Lim V, Musa SNA, Yakop F, Hairil Anuar AH

Artif Cells Nanomed Biotechnol, 2023 Dec;51(1):549-559.
PMID: 37847252 DOI: 10.1080/21691401.2023.2268167

This study aims to characterize and determine the antibacterial activities of synthesized Strobilanthes crispus-mediated AgNPs (SC-AgNPs) against Streptococcus mutans, Escherichia coli and Pseudomonas aeruginosa. S. crispus water extract acts as a reducing and capping agent in the synthesis of AgNPs. The synthesized AgNPs were characterized by using UV-Vis spectrophotometer, dynamic light scattering (DLS), field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and Fourier transform infra-red (FTIR). FESEM images showed a rough surface with a spherical shape. The average size distribution of 75.25 nm with a polydispersity index (PDI) of 0.373. XRD analysis matched the face-centred cubic structure of silver. FTIR analysis revealed a shifted peak from 1404.99 to 1345.00 cm-1. MIC and MBC values of SC-AgNPs were 1.25 mg/mL and 2.5 mg/mL against E. coli, P. aeruginosa and S. mutans, respectively. Time-kill assay showed that SC-AgNPs significantly reduced bacterial growth as compared to non-treated bacteria. Morphologies of bacteria treated with SC-AgNPs were shrunk, lysed, irregular and smaller as compared to control. SC-AgNPs significantly disrupted the gene expression of eae A, gtf B and Pel A (p

Matched MeSH terms: Escherichia coli
Antibiotic resistance through the lens of One Health: A study from an urban and a rural area in Sri Lanka

Gunasekara YD, Kottawatta SA, Nisansala T, Wijewickrama IJB, Basnayake YI, Silva-Fletcher A, et al.

Zoonoses Public Health, 2024 Feb;71(1):84-97.
PMID: 37880923 DOI: 10.1111/zph.13087

This study aimed to investigate and compare the proportion of AMR Escherichia coli (E. coli) between urban (Dompe in the Western province) and rural (Dambana in the Sabaragamuwa province) areas in Sri Lanka. The overall hypothesis of the study is that there is a difference in the proportion of AMR E. coli between the urban and the rural areas. Faecal samples were collected from healthy humans (n = 109), dairy animals (n = 103), poultry (n = 35), wild mammals (n = 81), wild birds (n = 76), soil (n = 80) and water (n = 80) from both areas. A total of 908 E. coli isolates were tested for susceptibility to 12 antimicrobials. Overall, E. coli isolated from urban area was significantly more likely to be resistant than those isolated from rural area. The human domain of the area had a significantly higher prevalence of AMR E. coli, but it was not significantly different in urban (98%) and rural (97%) areas. AMR E. coli isolated from dairy animals, wild animals and water was significantly higher in the urban area compared with the rural area. There was no significant difference in the proportion of multidrug resistance (MDR) E. coli isolated from humans, wild animals and water between the two study sites. Resistant isolates found from water and wild animals suggest contamination of the environment. A multi-sectorial One Health approach is urgently needed to control the spread of AMR and prevent the occurrences of AMR in Sri Lanka.

Matched MeSH terms: Escherichia coli
Fulltext Correlation between antibiotic consumption and the occurrence of multidrug-resistant organisms in a Malaysian tertiary hospital: a 3-year observational study

Tan SY, Khan RA, Khalid KE, Chong CW, Bakhtiar A

Sci Rep, 2022 Feb 24;12(1):3106.
PMID: 35210515 DOI: 10.1038/s41598-022-07142-2

Inappropriate use of antibiotics has been shown to contribute to the occurrence of multidrug-resistant organisms (MROs). A surveillance study was performed in the largest tertiary care hospital in Kuala Lumpur, Malaysia, from 2018 to 2020 to observe the trends of broad-spectrum antibiotics (beta-lactam/beta-lactamases inhibitors (BL/BLI), extended-spectrum cephalosporins (ESC), and fluoroquinolones (FQ)) and antibiotics against MRO (carbapenems, polymyxins, and glycopeptides) usage and the correlation between antibiotic consumption and MROs. The correlation between 3-year trends of antibiotic consumption (defined daily dose (DDD)/100 admissions) with MRO infection cases (per 100 admissions) was determined using a Jonckheere-Terpstra test and a Pearson's Correlation coefficient. The antimicrobial resistance trend demonstrated a positive correlation between ESC and FQ towards the development of methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp, ESBL-producing Escherichia coli (E. coli), and MRO Acinetobacter baumannii (A. baumannii). Increasing carbapenem consumption was positively correlated with the occurrence of ESBL-producing Klebsiella spp and E. coli. Polymyxin use was positively correlated with ESBL-producing Klebsiella spp, MRO A. baumannii, and carbapenem-resistant Enterobacteriaceae. The findings reinforced concerns regarding the association between MRO development, especially with a surge in ESC and FQ consumption. Stricter use of antimicrobials is thus crucial to minimise the risk of emerging resistant organisms.

Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli Infections/drug therapy
Recombinant LipL32 Protein Developed Using a Synthetic Gene Detects Leptospira-specific Antibodies in Human Serum Samples

Yaakob Y, Rodrigues KF, Opook F, William T, John DV

Malays J Med Sci, 2017 Oct;24(5):44-51.
PMID: 29386971 DOI: 10.21315/mjms2017.24.5.5

Background: Synthetic biology is emerging as a viable alternative for the production of recombinant antigens for diagnostic applications. It offers a safe alternative for the synthesis of antigenic principles derived from organisms that pose a high biological risk.
Methods: Here, we describe an enzyme-linked immunosorbent assay (ELISA) using the synthetic recombinant LipL32 (rLipL32) protein expressed in Escherichia coli for the detection of Leptospira-specific antibodies in human serum samples. The rLipL32-based ELISA was compared with a microscopic agglutination test (MAT), which is currently used as the gold standard for the diagnosis of leptospirosis.
Results: Our results showed that all the MAT-positive serum samples were positive for Leptospira-specific IgG in an ELISA, while 65% (n = 13) of these samples were also positive for Leptospira-specific IgM. In the MAT-negative serum samples, 80% and 55% of the samples were detected as negative by an ELISA for Leptospira-specific IgM and IgG, respectively.
Conclusion: An ELISA using the synthetic rLipL32 antigen was able to distinguish Leptospira-specific IgM (sensitivity 65% and specificity 80%) and IgG (sensitivity 100% and specificity 55%) in human serum samples and has the potential to serve as a rapid diagnostic test for leptospirosis.

Matched MeSH terms: Escherichia coli
Fulltext Sero-diagnostic evaluation of Toxoplasma gondii recombinant Rhoptry antigen 8 expressed in E. coli

Sonaimuthu P, Fong MY, Kalyanasundaram R, Mahmud R, Lau YL

Parasit Vectors, 2014;7:297.
PMID: 24986686 DOI: 10.1186/1756-3305-7-297

Toxoplasma gondii infects all warm-blooded animals, including humans. Early diagnosis and determining the infective stage are critical for effectively treating immunosuppressed individuals and pregnant women with toxoplasmosis. Among the rhoptry proteins of the parasite, Rhoptry protein 8 (ROP8), is known to be expressed during the early stages of T. gondii infection and is involved in parasitophorous vacuole formation. In this study, we have investigated the diagnostic efficacy of recombinant ROP8 (rROP8).

Matched MeSH terms: Escherichia coli/metabolism*
Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface

Saidin S, Chevallier P, Abdul Kadir MR, Hermawan H, Mantovani D

Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4715-24.
PMID: 24094179 DOI: 10.1016/j.msec.2013.07.026

Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316 L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24 h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3 days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24 h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7 days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application.

Matched MeSH terms: Escherichia coli/drug effects
Sterically tuned Ag(I)- and Pd(II)-N-heterocyclic carbene complexes of imidazol-2-ylidenes: synthesis, crystal structures, and in vitro antibacterial and anticancer studies

Haque RA, Salman AW, Budagumpi S, Abdullah AA, Majid AM

Metallomics, 2013 Jun;5(6):760-9.
PMID: 23645390 DOI: 10.1039/c3mt00051f

Unsymmetrically substituted sterically tuned Pd(II)–NHC complexes of the general formula [PdCl2(NHC)2] (NHC = 1-allyl-3-methylimidazolin-2-ylidene, 7; 1-allyl-3-butylimidazol-2-ylidene, 8; 1-benzyl-3-butyl imidazolin-2-ylidene, 9) were prepared through transmetallation from their corresponding Ag(I)–NHC complexes. The Pd complexes were structurally characterized by different spectroscopic and X-ray diffraction methods. Complexes 7 and 9 adopted a trans–anti arrangement of the NHC ligands, whereas complex 8 adopted a cis–syn arrangement. Preliminary antibiogram studies using Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria showed that Ag(I)–NHC complexes demonstrate higher activity compared with Pd(I)–NHC complexes. Furthermore, Pd(II)–NHC complexes were evaluated for their anticancer potential using the human colorectal cancer cell line. A higher anticancer activity was observed for complexes 8 and 9, with 26.5 and 6.6 mM IC50 values, respectively.

Matched MeSH terms: Escherichia coli/drug effects
In vitro modulatory effects of flavonoids on human cytochrome P450 2C8 (CYP2C8)

Pang CY, Mak JW, Ismail R, Ong CE

Naunyn Schmiedebergs Arch Pharmacol, 2012 May;385(5):495-502.
PMID: 22307090 DOI: 10.1007/s00210-012-0731-5

The inhibitory effects of five flavonoids with distinct chemical classes (flavones [luteolin], flavonols [quercetin and quercitrin], and flavanones [hesperetin and hespiridin]) on cDNA-expressed CYP2C8 were investigated. CYP2C8 was co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli and used to characterise potency and mechanism of these flavonoids on the isoform. Tolbutamide 4-methylhydroxylase, a high-performance liquid chromatography-based assay, was selected as marker activity for CYP2C8. Our results indicated that the flavonoids inhibited CYP2C8 with different potency. The order of inhibitory activities was quercetin > luteolin > hesperetin > hesperidin > quercitrin. All of these compounds however exhibited mechanism-based inhibition. A number of structural factors were found to be important for inhibition; these include the molecular shape (volume to surface ratio), the number of hydroxyl groups as well as glycosylation of the hydroxyl group. Quercetin was the most potent inhibitor among the flavonoids examined in this study, and our data suggest that it should be examined for potential pharmacokinetic drug interactions pertaining to CYP2C8 substrates in vivo.

Matched MeSH terms: Escherichia coli/genetics
Fulltext Structural modeling and biochemical characterization of recombinant KPN_02809, a zinc-dependent metalloprotease from Klebsiella pneumoniae MGH 78578

Wong MT, Choi SB, Kuan CS, Chua SL, Chang CH, Normi YM, et al.

Int J Mol Sci, 2012;13(1):901-17.
PMID: 22312293 DOI: 10.3390/ijms13010901

Klebsiella pneumoniae is a Gram-negative, cylindrical rod shaped opportunistic pathogen that is found in the environment as well as existing as a normal flora in mammalian mucosal surfaces such as the mouth, skin, and intestines. Clinically it is the most important member of the family of Enterobacteriaceae that causes neonatal sepsis and nosocomial infections. In this work, a combination of protein sequence analysis, structural modeling and molecular docking simulation approaches were employed to provide an understanding of the possible functions and characteristics of a hypothetical protein (KPN_02809) from K. pneumoniae MGH 78578. The computational analyses showed that this protein was a metalloprotease with zinc binding motif, HEXXH. To verify this result, a ypfJ gene which encodes for this hypothetical protein was cloned from K. pneumoniae MGH 78578 and the protein was overexpressed in Escherichia coli BL21 (DE3). The purified protein was about 32 kDa and showed maximum protease activity at 30 °C and pH 8.0. The enzyme activity was inhibited by metalloprotease inhibitors such as EDTA, 1,10-phenanthroline and reducing agent, 1,4-dithiothreitol (DTT). Each molecule of KPN_02809 protein was also shown to bind one zinc ion. Hence, for the first time, we experimentally confirmed that KPN_02809 is an active enzyme with zinc metalloprotease activity.

Matched MeSH terms: Escherichia coli/metabolism
Gene profiling and characterization of arginine kinase-1 (MrAK-1) from freshwater giant prawn (Macrobrachium rosenbergii)

Arockiaraj J, Vanaraja P, Easwvaran S, Singh A, Alinejaid T, Othman RY, et al.

Fish Shellfish Immunol, 2011 Jul;31(1):81-9.
PMID: 21549198 DOI: 10.1016/j.fsi.2011.04.004

Arginine kinase-1 (MrAK-1) was sequenced from the freshwater prawn Macrobrachium rosenbergii using Illumina Solexa Genome Analyzer Technique. MrAK-1 consisted of 1068 bp nucleotide encoded 355 polypeptide with an estimated molecular mass of 40 kDa. MrAK-1 sequence contains a potential ATP:guanido phosphotransferases active domain site. The deduced amino acid sequence of MrAK-1 was compared with other 7 homologous arginine kinase (AK) and showed the highest identity (96%) with AK-1 from cherry shrimp Neocaridina denticulate. The qRT-PCR analysis revealed a broad expression of MrAK-1 with the highest expression in the muscle and the lowest in the eyestalk. The expression of MrAK-1 after challenge with the infectious hypodermal and hematopoietic necrosis virus (IHHNV) was tested in muscle. In addition, MrAK-1 was expressed in Escherichia coli by prokaryotic expression plasmid pMAL-c2x. The optimum temperature (30 °C) and pH (8.5) was determined for the enzyme activity assay. MrAK-1 showed significant (P < 0.05) activity towards 10-50 mM ATP concentration. The enzyme activity was inhibited by α-ketoglutarate, glucose and ATP at the concentration of 10, 50 and 100 mM respectively. Conclusively, the findings of this study indicated that MrAK-1 might play an important role in the coupling of energy production and utilization and the immune response in shrimps.

Matched MeSH terms: Escherichia coli/genetics
Leachate characterization in semi-aerobic and anaerobic sanitary landfills: a comparative study

Aziz SQ, Aziz HA, Yusoff MS, Bashir MJ, Umar M

J Environ Manage, 2010 Dec;91(12):2608-14.
PMID: 20739117 DOI: 10.1016/j.jenvman.2010.07.042

This study analyzes and compares the results of leachate composition at the semi-aerobic Pulau Burung Landfill Site (PBLS) (unaerated pond and intermittently aerated pond) and the anaerobic Kulim Sanitary Landfill in the northern region of Malaysia. The raw samples were collected and analyzed for twenty parameters. The average values of the parameters such as phenols (1.2, 6.7, and 2.6 mg/L), total nitrogen (448, 1200, and 300 mg/L N-TN), ammonia-N (542, 1568, and 538 mg/L NH(3)-N), nitrite (91, 49, and 52 mg/L NO(2)(-)-N), total phosphorus (21, 17, and 19 mg/L), BOD(5) (83, 243, and 326 mg/L), COD (935, 2345, and 1892 mg/L), BOD(5)/COD (0.096,0.1124,0.205%), pH (8.20, 8.28, and 7.76), turbidity (1546, 180, and 1936 Formazin attenuation units (FAU)), and color (3334, 3347, and 4041 Pt Co) for leachate at the semi-aerobic PBLS (unaerated and intermittently aerated) and the anaerobic Kulim Sanitary Landfill were recorded, respectively. The obtained results were compared with previously published data and data from the Malaysia Environmental Quality Act 1974. The results indicated that Pulau Burung leachate was more stabilized compared with Kulim leachate. Furthermore, the aeration process in PBLS has a considerable effect on reducing the concentration of several pollutants. The studied leachate requires treatment to minimize the pollutants to an acceptable level prior to discharge into water courses.

Matched MeSH terms: Escherichia coli/isolation & purification
Optimal methods for evaluating antimicrobial activities from plant extracts

Othman M, Loh HS, Wiart C, Khoo TJ, Lim KH, Ting KN

J Microbiol Methods, 2011 Feb;84(2):161-6.
PMID: 21094190 DOI: 10.1016/j.mimet.2010.11.008

The search for antimicrobial agents from plants has been a growing interest in the last few decades. However, results generated from many of these studies cannot be directly compared due to the absence of standardization in particular antimicrobial methods employed. The need for established methods with consistent results for the evaluation of antimicrobial activities from plant extracts has been proposed by many researchers. Nevertheless, there are still many studies reported in the literature describing different methodologies. The aim of this study was to find optimal methods to give consistent quantitative antimicrobial results for studying plant extracts. Three different agar-based assays (pour plate disc diffusion (PPDD), streak plate disc diffusion (SPDD) and well-in agar (WA)) and one broth-based (turbidometric (TB)) assay were used in this study. Extracts from two plant species (Duabanga grandiflora and Acalypha wilkesiana) were tested on two bacterial species, namely Escherichia coli and Staphylococcus aureus. Amongst the agar-based assays, PPDD produced the most reproducible results. TB was able to show the inhibitory effects of the test samples on the growth kinetic of the bacteria including plant extracts with low polarity. We propose that both agar- (i.e PPDD) and broth-based assays should be employed when assessing the antimicrobial activity of plant crude extracts.

Matched MeSH terms: Escherichia coli/drug effects*
Fever/clinical signs and association with neutropenia in solid cancer patients--bacterial infection as the main cause

Rasool Hassan BA, Yusoff ZB, Othman SB

Asian Pac J Cancer Prev, 2010;11(5):1273-7.
PMID: 21198276

INTRODUCTION: Neutropenia remains one of the serious side effects of chemotherapeutics drugs making cancer patients face serious risk of infections. Fever and clinical signs are considered as important indicators. The objectives of this study were to assess fever and clinical signs with neutropenia onset and/ or severity in solid cancer cases, using culture tests to determine the type of bacteria predominating, whether gram positive or gram negative.
METHODS: This observational retrospective study was conducted on files of all solid cancer patients who admitted to a general hospital between 1 January 2003 and 31 December 2006. All data were categorical and analyzed for association with neutropenia.
RESULTS: 117 neutropenic patients were studied, 83 (70.9%) of them suffering from fever ranging between 38.5-39 °C, with hypotension (53; 27.3%) and headache 51 (26.3%) as the most common clinical signs. Only 34 (29.1%) neutropenic patients underwent culture testing and only 14 (41.2%) showed positive growth, gram negative types predominating (9; 64.2%), mainly Escherichia coli (5; 35.7%), with gram positive only in 5 (35.7%). Significant associations were found for fever and clinical signs with neutropenia severity (P<0.05), but not neutropenia onset (P>0.05). Logistic regression results showed strong significant association between presence of fever (P=0.02, OR=1.3) (95% confidence interval (CI)) hypotension and headache (P=0.001, OR=1.148) (95% CI) with neutropenia severity.
CONCLUSION: Fever and clinical signs specifically headache and hypotension are symptoms associated with severe neutropenia in solid cancer patients. Both may primarily result from bacterial infection, particularly gram negative forms.

Matched MeSH terms: Escherichia coli/isolation & purification

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