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A rapid colorimetric screening method for vanillic acid and vanillin-producing bacterial strains

Zamzuri NA, Abd-Aziz S, Rahim RA, Phang LY, Alitheen NB, Maeda T

J Appl Microbiol, 2014 Apr;116(4):903-10.
PMID: 24314059 DOI: 10.1111/jam.12410

To isolate a bacterial strain capable of biotransforming ferulic acid, a major component of lignin, into vanillin and vanillic acid by a rapid colorimetric screening method.

Matched MeSH terms: Pseudomonas/isolation & purification; Pseudomonas/metabolism*
Fulltext Biotransformasi asid oleik oleh Pseudomonas sp. Strain SS22

Zaleha Shafiei, Che Nyonya Abdul Razak, Abu Bakar Salleh, Mahiran Basri, Misri Kusnan

Jurnal Sains Kesihatan Malaysia, 2006;4(1):47-58.
MyJurnal

Pseudomonas sp. strain SS22 telah dipencilkan daripada kolam oksidasi kilang minyak kelapa sawit di Malaysia. Dalam kajian ini, keupayaaan bakteria ini mentransformasikan asid oleik kepada produk baru telah dikaji. Produk biotransformasi dianalisis dengan kromatografi lapisan nipis (KLN), kromatografi gas (KG), spektroskopi inframerah gandingan fourier (SIGF) dan kromatografi gas-spektrometri jisim (KG-s.1). Analisis KLN menunjukkan bahawa hanya satu produk baru terbentuk selepas 7 hari eraman pada suhu 37°C, goncangan pada 150 ppm. Semakin lama eraman menyebabkan pengurangan titik produk pada 14 harL Analisis KG menunjukkan bahawa 5 puncak produk baru pada masa penahanan 13.1(*A), 15.0 (*C), 15.3 (*D), 16.8 (*E) dan 18.4 (*F) minit telah terbentuk selepas 7 hari eraman. Spektrum inframerah (Im) bagi produk yang terbentuk daripada asid oleik selepas 7 hari, menunjukkan kewujudan regangan OH/NH pada 3417 cm-'. Serapan pada 2673 cm-', kemungkinan regangan CH bersama-sama dengan kumpulan karbonil. Serapan pada 1712 cm-' adalah konstan dengan regangan c=o daripada keton atau asid karboksilik. Regangan CH pada 2932, 2854, 1462 dan 1379 cm-1 merupakan kumpulan alkil, menandakan produk hidrokarbon juga wujud dalam produk campuran. Kehadiran CH/C-C pada serapan 969 dan 725 cm-', menandakan kewujudan alkena trans (C=C). Analisis KG-SJ mengesahkan bahawa produk tersebut merupakan campuran asid 9(E)- heksadekenoik, asid kaprilik, asid miristik dan hidrokarbon. Walaupun produk yang terbentuk bercampur, asid 9(E)-heksadekenoik boleh digunakan sebagai komponen membran lipidnya. Penghasilan produk tersebut boleh dipertingkatkan dengan mengoptimumkan keadaan pertumbuhan.

Matched MeSH terms: Pseudomonas
Rational use of intravenous polymyxin B and colistin: A review

Zakuan ZD, Suresh K

Med J Malaysia, 2018 10;73(5):351-359.
PMID: 30350826 MyJurnal

Polymyxin B and colistin (polymyxin E) were introduced in clinical practice to treat Gram-negative infections in 1950s but their parenteral use waned in 1970s due to toxicity concerns. Resurgence of polymyxins use in Malaysia began approximately in 2009 due to a lack of treatment options for MDR Gram negative superbugs such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. However, limited experience and a lack of widespread availability of up-to-date dosing guidelines could potentially result in incorrect use of these last resort antibiotics by managing doctors. The recent report of polymyxin resistant strains is also a cause of concern. Herein, we discuss the importance of preserving the efficacy of polymyxins in hospitals, the similarities and differences between polymyxin B and colistin, issues pertaining to current use of polymxyins and strategies to improve polymyxins' prescription. Polymyxins should only be used to treat significant infections, in optimum doses and if possible, in combination with other antibiotics.

Matched MeSH terms: Pseudomonas aeruginosa
Fulltext Antibacterial activity of selected Malaysian honey

Zainol MI, Mohd Yusoff K, Mohd Yusof MY

BMC Complement Altern Med, 2013;13:129.
PMID: 23758747 DOI: 10.1186/1472-6882-13-129

Antibacterial activity of honey is mainly dependent on a combination of its peroxide activity and non-peroxide components. This study aims to investigate antibacterial activity of five varieties of Malaysian honey (three monofloral; acacia, gelam and pineapple, and two polyfloral; kelulut and tualang) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa.

Matched MeSH terms: Pseudomonas aeruginosa/drug effects; Pseudomonas aeruginosa/growth & development
Fulltext Pseudomonas laryngeal perichondritis: unexpected diagnosis

Zainal Abidin SS, Kew TY, Azman M, Mat Baki M

BMJ Case Rep, 2020 Dec 22;13(12).
PMID: 33370978 DOI: 10.1136/bcr-2020-237129

A 57-year-old male chronic smoker with underlying diabetes mellitus presented with dysphonia associated with cough, dysphagia and reduced effort tolerance of 3 months' duration. Videoendoscope finding revealed bilateral polypoidal and erythematous true and false vocal fold with small glottic airway. The patient was initially treated as having tuberculous laryngitis and started on antituberculous drug. However, no improvement was observed. CT of the neck showed erosion of thyroid cartilage, which points to laryngeal carcinoma as a differential diagnosis. However, the erosion was more diffuse and appeared systemic in origin. The diagnosis of laryngeal perichondritis was made when the histopathological examination revealed features of inflammation, and the tracheal aspirate isolated Pseudomonas aeruginosa The patient made a good recovery following treatment with oral ciprofloxacin.

Matched MeSH terms: Pseudomonas aeruginosa/isolation & purification*; Pseudomonas Infections/complications; Pseudomonas Infections/diagnosis*; Pseudomonas Infections/drug therapy; Pseudomonas Infections/microbiology
Identification of Nasal Irrigation Bottle Contamination in Post Sinonasal Surgery

Zahedi FD, Asmi NH, Husain S, Gendeh BS

Indian J Otolaryngol Head Neck Surg, 2019 Nov;71(Suppl 3):1837-1842.
PMID: 31763256 DOI: 10.1007/s12070-017-1219-x

Nasal irrigation is an effective and cheap method in managing post sinonasal surgery patients. It works by improving ciliary clearance and performing mechanical debridement of the thick crust, decreasing mucosal edema and reducing the inflammatory mediators. Presence of nasal irrigation bottle contamination and its effect on patients have been studied. The aim of this study is to prospectively identify the risk of contamination in the nasal irrigation bottle, fluid from the bottle and to correlate with endoscopic findings from the patients who had underwent sinonasal surgery. Swabs will be taken from the nasal irrigation bottle and patient's middle meatus before the surgery and at each post surgery visits (2 and 4 weeks). Patients will be advised to irrigate their nose three times per day post sinonasal surgery. During endoscopic examination of the patient's nasal cavity at 2 and 4 weeks, any evidence of infection will be noted and documented. Additionally, a swab of fluid irrigated from the nasal cavity collected during the clinic follow-ups will also be taken. The specimens will be sent to the Microbiology laboratory for standard culture and sensitivity test. A total of 27 patients completed the study and were divided into case (n = 15) and control (n = 12) groups. The CFU (colony-forming unit) value of the bacteria cultured from the nasal cavity and the nasal irrigation bottle was statistically significantly (P = 0.00) increased from the baseline to the second week follow-up in both groups but not from the second week to the fourth week follow-up. The majority of the swabs from the nasal cavity of the patients and the nasal irrigation bottles were positively cultured for Pseudomonas sp. group. Other groups of bacteria that were cultured were Enterobacter sp., Coagulase Negative Staphylococcus (CONS) and Klebsiella sp. Endoscopically, there was no clinical evidence of infection found in the nasal cavity of the patients. The nasal irrigation bottle that was used in the post sinonasal surgery treatment and for alleviation of symptoms of sinonasal diseases was found to have bacterial contamination from the swabs taken from the bottle. However, despite this finding there was not clinical evidence of infection noted from the nasal endoscopic examination. A simple and effective method of cleaning the bottle would be helpful to reduce the bacterial contamination for this useful treatment method.

Matched MeSH terms: Pseudomonas
Synthesis, characterization and antibacterial activity of mono-, di- and tri-tosylate of glycerol

Yusrabbil Amiyati Yusof, Azhar Ariffin

Sains Malaysiana, 2016;45:621-625.

Glycerol is a valuable co-product from oleochemical industry such as from fatty acid and biodiesel production. By having three hydroxyl groups in its molecule, glycerol can undergo chemical modifications that lead to many possible applications. This paper reports the tosylation process of glycerol with para-toluenesulfonyl chloride (p-TsCl). Reaction of glycerol with p-TsCl in the presence of a base produced mono-, di- and tri-tosylate of glycerol even though the reaction was carried out at the mole ratio of 1.2:1.0 of glycerol to p-TsCl. The compounds were successfully isolated and characterized. Mono-, di- and tri-tosylate of glycerol exhibited inhibitory activity against Staphylococcus aureus (gram positive bacteria) and Pseudomonas aeruginosa (gram negative bacteria).

Matched MeSH terms: Pseudomonas aeruginosa
Fulltext Pseudomonas cremoricolorata strain ND07 produces N-acyl homoserine lactones as quorum sensing molecules

Yunos NY, Tan WS, Koh CL, Sam CK, Mohamad NI, Tan PW, et al.

Sensors (Basel), 2014;14(7):11595-604.
PMID: 24984061 DOI: 10.3390/s140711595

Quorum sensing (QS) is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs). We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-L-homoserine lactone (C8-HSL) and N-decanoyl-L-homoserine lactone (C10-HSL). To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

Matched MeSH terms: Pseudomonas/classification*; Pseudomonas/isolation & purification; Pseudomonas/physiology*
Fulltext Immunomodulatory Effects and Mechanisms of Curcuma Species and Their Bioactive Compounds: A Review

Yuandani, Jantan I, Rohani AS, Sumantri IB

Front Pharmacol, 2021;12:643119.
PMID: 33995049 DOI: 10.3389/fphar.2021.643119

Curcuma species (family: Zingiberaceae) are widely utilized in traditional medicine to treat diverse immune-related disorders. There have been many scientific studies on their immunomodulating effects to support their ethnopharmacological uses. In this review, the efficacy of six Curcuma species, namely, C. longa L., C. zanthorrhiza Roxb., C. mangga Valeton & Zijp, C. aeruginosa Roxb. C. zedoaria (Christm.) Roscoe, and C. amada Roxb., and their bioactive metabolites to modulate the immune system, their mechanistic effects, and their potential to be developed into effective and safe immunomodulatory agents are highlighted. Literature search has been carried out extensively to gather significant findings on immunomodulating activities of these plants. The immunomodulatory effects of Curcuma species were critically analyzed, and future research strategies and appropriate perspectives on the plants as source of new immunomodulators were discussed. Most of the pharmacological investigations to evaluate their immunomodulatory effects were in vivo and in vitro experiments on the crude extracts of the plants. The extracts were not chemically characterized or standardized. Of all the Curcuma species investigated, the immunomodulatory effects of C. longa were the most studied. Most of the bioactive metabolites responsible for the immunomodulating activities were not determined, and mechanistic studies to understand the underlying mechanisms were scanty. There are limited clinical studies to confirm their efficacy in human. Of all the bioactive metabolites, only curcumin is undergoing extensive clinical trials based on its anti-inflammatory properties and main use as an adjuvant for the treatment of cancer. More in-depth studies to understand the underlying mechanisms using experimental in vivo animal models of immune-related disorders and elaborate bioavailability, preclinical pharmacokinetics, and toxicity studies are required before clinical trials can be pursued for development into immunomodulatory agents.

Matched MeSH terms: Pseudomonas aeruginosa
Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

Yong YY, Dykes G, Lee SM, Choo WS

J Appl Microbiol, 2019 Jan;126(1):68-78.
PMID: 30153380 DOI: 10.1111/jam.14091

AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.
METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml-1 ) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml-1 ) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.
CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.
SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.

Matched MeSH terms: Pseudomonas aeruginosa/drug effects*; Pseudomonas aeruginosa/genetics; Pseudomonas aeruginosa/physiology
Betacyanin-inhibited biofilm formation of co-culture of Staphylococcus aureus and Pseudomonas aeruginosa on different polymer surfaces

Yong YY, Ong MWK, Dykes G, Choo WS

FEMS Microbiol Lett, 2021 01 26;368(1).
PMID: 33338235 DOI: 10.1093/femsle/fnaa214

Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A combination of each betacyanin fraction (0.625 mg mL-1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24-3.84 and 1.25-3.52 to 0.81-2.63 and 0.80-1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0-1.3 log CFU cm-2 bacterial attachment on polymer surfaces such as polyvinyl chloride, polyethylene, polypropylene and silicone rubber. This study demonstrated an increase in biofilm-inhibiting activity against biofilms formed by two species using combined fractions than that by using single fractions. Betacyanins found in different plants could collectively be used to potentially decrease the risk of biofilm-associated infections caused by these bacteria on hydrophobic polymers.

Matched MeSH terms: Pseudomonas aeruginosa/drug effects*; Pseudomonas aeruginosa/physiology
Fulltext Bacteriology of diabetic foot lesions

Yoga R, Khairul A, Sunita K, Suresh C

Med J Malaysia, 2006 Feb;61 Suppl A:14-6.
PMID: 17042222

Infection plays a pivotal role in enhancing a diabetic foot at risk toward amputation. Effective antibiotic therapy against the offending pathogens is an important component of treatment of diabetic foot infections. Recognition of the pathogen is always difficult as the representative deep tissue sample for culture is surrounded by ulcer surface harbouring colonies of organisms frequently labelled as skin commensals. The emergent of resistant strains represents a compounding problem standing against efforts to prevent amputation. This study was undertaken to identify the pathogens associated with diabetic foot infection in terms of their frequency and sensitivity against certain commonly used antibiotics. Forty-four consecutive patients with open diabetic foot infections had wound swab taken for culture and sensitivity testing. Cultures positive were observed in 89% of the cases with Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeroginosa encountered in 20%, 14% and 14% of cases respectively. Mixed growths were isolated in 6% of cultures. All Staphylcoccus aureus isolates were resistant to Penicillin but 80% were sensitive to Erythromycin and Co-trimoxazole. Klebsiella pneumoniae isolates were sensitive to Methicillin and Gentamycin in 80% and 60% of cases respectively, and resistant to Ampicillin and Ceftazidime in 83% and 50% respectively. All Pseudomonas aeroginosa isolates were sensitive to Amikacin and Ciprofloxacin but 50% were resistant to Gentamycin. There was no single antibiotic possessing good coverage for all common organisms isolated from diabetic foot lesions. Staphylococcus aureus remains the predominant cause of diabetic foot infections followed by Klebsiela pneumonia and Pseudomonas aeroginosa. Most infections are monomicrobial. The emergence of multiresistant organisms is a worrying feature in diabetic foot infections.

Matched MeSH terms: Pseudomonas aeruginosa/isolation & purification*
Fulltext Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition

Yip CH, Mahalingam S, Wan KL, Nathan S

PLoS One, 2021;16(6):e0253445.
PMID: 34161391 DOI: 10.1371/journal.pone.0253445

Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.

Matched MeSH terms: Pseudomonas aeruginosa/drug effects; Pseudomonas aeruginosa/growth & development
Characterization of hbzE-encoded gentisate 1,2-dioxygenase from Pseudomonas alcaligenes NCIMB 9867

Yeo CC, Tan CL, Gao X, Zhao B, Poh CL

Res. Microbiol., 2007 Sep;158(7):608-16.
PMID: 17720458

Pseudomonas alcaligenes NCIMB 9867 (strain P25X) is known to synthesize two isofunctional gentisate 1,2-dioxygenases (GDO; EC 1.13.11.4) as well as other enzymes involved in the degradation of xylenols and cresols via the gentisate pathway. The hbzE gene encoding what is possibly the strictly inducible gentisate 1,2-dioxygenase II (GDO-II) was cloned, overexpressed and purified as a hexahistidine fusion protein from Escherichia coli. Active recombinant GDO-II had an estimated molecular mass of 150kDa and is likely a tetrameric protein with a subunit mass of approximately 40kDa, similar to the previously characterized gentisate 1,2-dioxygenase I (GDO-I) encoded by xlnE. However, GDO-II was unable to utilize gentisate that is substituted at the carbon-4 position, unlike GDO-I which had broader substrate specificity. GDO-II also possessed different kinetic characteristics when compared to GDO-I. The hbzE-encoded GDO-II shared higher sequence identities (53%) with GDOs from Ralstonia sp. U2 and Polaromonas naphthalenivorans CJ2, compared with only 35% identity with the xlnE-encoded GDO-I. The hbzE gene was found to be part of a cluster of nine genes including the putative regulatory gene designated hbzR, which encodes an LysR-type regulator and is divergently transcribed from the other genes of the hbzHIJKLFED cluster.

Matched MeSH terms: Pseudomonas alcaligenes/enzymology*; Pseudomonas alcaligenes/genetics*
Fulltext Isolation and characterization of a metal-reducing Pseudomonas sp. strain 135 with amide-degrading capability

Yakasai, M.H., Rahman, M.F., Khayat, M.E., Shukor, M.Y., Shamaan, N.A., Rahim, M.B.H.A.

Bioremediation Science and Technology Research, 2017;5(2):32-38.
MyJurnal

The presence of both heavy metals and organic xenobiotic pollutants in a contaminated site
justifies the application of either a multitude of microbial degraders or microorganisms having
the capacity to detoxify a number of pollutants at the same time. Molybdenum is an essential
heavy metal that is toxic to ruminants at a high level. Ruminants such as cow and goats
experience severe hypocuprosis leading to scouring and death at a concentration as low as
several parts per million. In this study, a molybdenum-reducing bacterium with amide-degrading
capacity has been isolated from contaminated soils. The bacterium, using glucose as the best
electron donor reduces molybdenum in the form of sodium molybdate to molybdenum blue. The
maximal pH reduction occurs between 6.0 and 6.3, and the bacterium showed an excellent
reduction in temperatures between 25 and 40 oC. The reduction was maximal at molybdate
concentrations of between 15 and 25 mM. Molybdenum reduction incidentally was inhibited by
several toxic heavy metals. Other carbon sources including toxic xenobiotics such as amides
were screened for their ability to support molybdate reduction. Of all the amides, only
acrylamide can support molybdenum reduction. The other amides; such as acetamide and
propionamide can support growth. Analysis using phylogenetic analysis resulted in a tentative
identification of the bacterium as Pseudomonas sp. strain 135. This bacterium is essential in
remediating sites contaminated with molybdenum, especially in agricultural soil co-contaminated
with acrylamide, a known soil stabilizer.

Matched MeSH terms: Pseudomonas
Antibiofilm activity and mode of action of DMSO alone and its combination with afatinib against Gram-negative pathogens

Yahya MFZR, Alias Z, Karsani SA

Folia Microbiol (Praha), 2018 Jan;63(1):23-30.
PMID: 28540585 DOI: 10.1007/s12223-017-0532-9

Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm-1 were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.

Matched MeSH terms: Pseudomonas aeruginosa/drug effects*; Pseudomonas aeruginosa/physiology
Toluene promotes lid 2 interfacial activation of cold active solvent tolerant lipase from Pseudomonas fluorescens strain AMS8

Yaacob N, Mohamad Ali MS, Salleh AB, Rahman RNZRA, Leow ATC

J Mol Graph Model, 2016 07;68:224-235.
PMID: 27474867 DOI: 10.1016/j.jmgm.2016.07.003

The utilization of cold active lipases in organic solvents proves an excellent approach for chiral synthesis and modification of fats and oil due to the inherent flexibility of lipases under low water conditions. In order to verify whether this lipase can function as a valuable synthetic catalyst, the mechanism concerning activation of the lid and interacting solvent residues in the presence of organic solvent must be well understood. A new alkaline cold-adapted lipase, AMS8, from Pseudomonas fluorescens was studied for its structural adaptation and flexibility prior to its exposure to non-polar, polar aprotic and protic solvents. Solvents such as ethanol, toluene, DMSO and 2-propanol showed to have good interactions with active sites. Asparagine (Asn) and tyrosine (Tyr) were key residues attracted to solvents because they could form hydrogen bonds. Unlike in other solvents, Phe-18, Tyr-236 and Tyr-318 were predicted to have aromatic-aromatic side-chain interactions with toluene. Non-polar solvent also was found to possess highest energy binding compared to polar solvents. Due to this circumstance, the interaction of toluene and AMS8 lipase was primarily based on hydrophobicity and molecular recognition. The molecular dynamic simulation showed that lid 2 (residues 148-167) was very flexible in toluene and Ca(2+). As a result, lid 2 moves away from the catalytic areas, leaving an opening for better substrate accessibility which promotes protein activation. Only a single lid (lid 2) showed the movement following interactions with toluene, although AMS8 lipase displayed double lids. The secondary conformation of AMS8 lipase that was affected by toluene observed a reduction of helical strands and increased coil structure. Overall, this work shows that cold active lipase, AMS8 exhibits distinguish interfacial activation and stability in the presence of polar and non-polar solvents.

Matched MeSH terms: Pseudomonas fluorescens/enzymology*
Fulltext The Role of Solvent-Accessible Leu-208 of Cold-Active Pseudomonas fluorescens Strain AMS8 Lipase in Interfacial Activation, Substrate Accessibility and Low-Molecular Weight Esterification in the Presence of Toluene

Yaacob N, Ahmad Kamarudin NH, Leow ATC, Salleh AB, Raja Abd Rahman RNZ, Mohamad Ali MS

Molecules, 2017 Aug 12;22(8).
PMID: 28805665 DOI: 10.3390/molecules22081312

The alkaline cold-active lipase from Pseudomonas fluorescens AMS8 undergoes major structural changes when reacted with hydrophobic organic solvents. In toluene, the AMS8 lipase catalytic region is exposed by the moving hydrophobic lid 2 (Glu-148 to Gly-167). Solvent-accessible surface area analysis revealed that Leu-208, which is located next to the nucleophilic Ser-207 has a focal function in influencing substrate accessibility and flexibility of the catalytic pocket. Based on molecular dynamic simulations, it was found that Leu-208 strongly facilitates the lid 2 opening via its side-chain. The KM and Kcat/KM of L208A mutant were substrate dependent as it preferred a smaller-chain ester (pNP-caprylate) as compared to medium (pNP-laurate) or long-chain (pNP-palmitate) esters. In esterification of ethyl hexanoate, L208A promotes a higher ester conversion rate at 20 °C but not at 30 °C, as a 27% decline was observed. Interestingly, the wild-type (WT) lipase's conversion rate was found to increase with a higher temperature. WT lipase AMS8 esterification was higher in toluene as compared to L208A. Hence, the results showed that Leu-208 of AMS8 lipase plays an important role in steering a broad range of substrates into its active site region by regulating the flexibility of this region. Leu-208 is therefore predicted to be crucial for its role in interfacial activation and catalysis in toluene.

Matched MeSH terms: Pseudomonas fluorescens/metabolism
Fulltext Antarctic bacteria inhibit the growth of pathogens

Wong, C.M.V.L., Chung, H.H., Aisyah, S., Omar, S., Cheah, Y.K., Maria de, L.G., et al.

ASM Science Journal, 2009;3(2):107-112.
MyJurnal

There are relatively little data on bacteria with antimicrobial activities from Antarctic, especially from the South Shetland Islands when compared to the other parts of the world. Hence, this project was set to isolate and characterize bacteria that produce anti-microbial compounds from Greenwich Island (one of the South Shetland Islands), Antarctica. A total of 356 strains of bacteria were isolated from Greenwich Island. They were screened for antimicrobial activities against 13 Gram-negative and one Gram-positive indicator food-borne pathogens. Two out of the 356 Antarctic bacterial strains exhibited an antagonistic effect on the indicator strains, Escherichia coli, Salmonella spp., Klebsiella pneumoniae, Enterobacter cloacae, Vibrio parahaemolyticus and Bacillus cereus. The two Antarctic bacterial strains were designated as SS157 and SR13. Biochemical and 16S rDNA analysis indicated that the strain SS157 was closely related to Pseudomonas congelans while the strain SR13 was closely related to Pseudomonas tremae. The anti-microbial compounds produced by the two Antarctic bacteria were not sensitive to temperature and were not degraded by trypsin or pronase indicating that they were likely to be chemical compounds or antibiotics. Antimicrobial compounds from strains SS157 and SR13 were broad spectrum, and targeted both Gram-positive and negative pathogens.

Matched MeSH terms: Pseudomonas
Carboxymethylcellulose film for bacterial wound infection control and healing

Wong TW, Ramli NA

Carbohydr Polym, 2014 Nov 4;112:367-75.
PMID: 25129756 DOI: 10.1016/j.carbpol.2014.06.002

Infection control and wound healing profiles of sodium carboxymethylcellulose (SCMC) films were investigated as a function of their anti-bacterial action, physical structures, polymer molecular weights and carboxymethyl substitution degrees. The films were prepared with in vitro polymer/film and in vivo microbe-colonized wound healing/systemic infection profiles examined. Adhesive high carboxymethyl substituted SCMC films aided healing via attaching to microbes and removing them from wound. Pseudomonas aeruginosa was removed via encapsulating in gelling low molecular weight SCMC film, whereas Staphylococcus aureus was trapped in tight folds of high molecular weight SCMC film. Incomplete microbe removal from wound did not necessary translate to inability to heal as microbe remnant at wound induced fibroblast migration and aided tissue reconstruction. Using no film nonetheless will cause systemic blood infection. SCMC films negate infection and promote wound healing via specific polymer-microbe adhesion, and removal of S. aureus and P. aeruginosa requires films of different polymer characteristics.

Matched MeSH terms: Pseudomonas aeruginosa/pathogenicity; Pseudomonas Infections/prevention & control

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