scholarly journals Use of Tetra-ammonium Tetrakis(4-Sulphonato)Phenyl Porphyrin forPseudomonasandBacillusCell Imaging

2010 ◽  
Vol 2010 ◽  
pp. 1-3
Author(s):  
V. Sujatha ◽  
Bharat Sridhar ◽  
Srinath Krishnamurthy ◽  
K. S. Vinod Kumar ◽  
K. Senthil Kumar ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Cereus ◽  
Fluorescent Microscopy ◽  
Water Soluble ◽  
Bacterial Cells

The use of tetraammonium tetrakis(4-sulphonato)phenyl porphyrin (TPPS), a water-soluble anionic compound, as a stain to analyse bacterial cells using fluorescent microscopy was investigated. TPPS was effectively used to analyse two different bacteria:Pseudomonas aeruginosaandBacillus cereus. The variation in brightness with varying concentrations of TPPS was studied. The patterns of variations for these bacteria were found to be the same, but with consistently higher brightness forBacillus cereus.

scholarly journals The physical boundaries of public goods cooperation between surface-attached bacterial cells

2017 ◽  
Author(s):  
Michael Weigert ◽  
Rolf Kümmerli
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Soft Tissue ◽  
Social Interactions ◽  
Single Cell ◽  
Fluorescent Microscopy ◽  
Social Consequences ◽  
Social Effects ◽  
Bacterial Cells ◽  
Soft Tissue Infections ◽  
Natural Conditions

AbstractBacteria secrete a variety of compounds important for nutrient scavenging, competition mediation and infection establishment. While there is a general consensus that secreted compounds can be shared and therefore have social consequences for the bacterial collective, we know little about the physical limits of such bacterial social interactions. Here, we address this issue by studying the sharing of iron-scavenging siderophores between surface-attached microcolonies of the bacterium Pseudomonas aeruginosa. Using single-cell fluorescent microscopy, we show that siderophores, secreted by producers, quickly reach non-producers within a range of 100 μm, and significantly boost their fitness. Producers in turn respond to variation in sharing efficiency by adjusting their pyoverdine investment levels. These social effects wane with larger cell-to-cell distances and on hard surfaces. Thus, our findings reveal the boundaries of compound sharing, and show that sharing is particularly relevant between nearby yet physically separated bacteria on soft surfaces, matching realistic natural conditions such as those encountered in soft tissue infections.

PENGUJIAN KONSORSIUM BAKTERI ANTAGONIS UNTUK MENGENDALIKAN PENYAKIT BERCAK DAUN CERCOSPORA DAN VIRUS KUNING PADA TANAMAN CABAI MERAH BESAR (Capsicum annum L.) DI KECAMATAN DAMPIT KABUPATEN MALANG

2021 ◽  
Vol 9 (3) ◽  
pp. 107-114
Author(s):  
Diyana Lestari ◽  
Luqman Qurata Aini
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Cereus ◽  
Duncan Multiple Range Test ◽  
Capsicum Annum ◽  
Range Test

Penyakit virus kuning dan bercak daun Cercospora merupakan dua penyakit penting yang menjadi kendala dalam budidaya cabai merah besar. Penelitian ini bertujuan untuk menguji konsorsium bakteri antagonis Pseudomonas aeruginosa dan Bacillus cereus dalam mengendalikan penyakit virus kuning dan bercak daun Cercospora pada cabai merah besar serta pengaruhnya terhadap pertumbuhan tanaman cabai merah besar sendiri. Penelitian dilaksanakan pada bulan Oktober 2020 - Desember 2020 di lahan tumpangsari bawang merah dan cabai, Desa Ubalan, Kecamatan Dampit, Kabupaten Malang. Persiapan penelitian meliputi survei lokasi, persiapan alat dan bahan, pengacakan perlakuan, dan penentuan tanaman sampel. Pelaksanaan penelitian meliputi pengaplikasian larutan isolat bakteri antagonis di lapang, pengamatan mingguan, dan pengolahan data. Penelitian disusun menggunakan Rancangan Acak Kelompok (RAK) dengan 9 perlakuan dan 3 ulangan. Data dianalisis menggunakan sidik ragam ANOVA dan uji lanjut DMRT (Duncan Multiple Range Test) pada taraf 5% menggunakan software DSAASTAT. Konsorsium P7 (Pseudomonas aeruginosa + Bacillus cereus 13) lebih efektif dalam menekan penyakit virus kuning, sedangkan perlakuan konsorsium P8 (Bacillus cereus 12 + Bacillus cereus 13) lebih efektif dalam menekan penyakit bercak daun Cercospora. Perlakuan konsorsium tidak memberikan pengaruh terhadap tinggi dan jumlah daun. Namun, konsorsium P7 mampu meningkatkan bobot tanaman cabai meskipun secara statistik tidak berbeda dengan perlakuan lainnya.

Pseudomonas aeruginosa Oligoribonuclease Controls Susceptibility to Polymyxin B by Regulating Pel Exopolysaccharide Production

2022 ◽  
Author(s):  
Baopeng Yang ◽  
Yujun Jiang ◽  
Yongxin Jin ◽  
Fang Bai ◽  
Zhihui Cheng ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Resistance ◽  
Defense Mechanism ◽  
Extracellular Polysaccharide ◽  
Opportunistic Pathogen ◽  
Polymyxin B ◽  
Guanosine Monophosphate ◽  
Extracellular Dna ◽  
Bacterial Cells ◽  
Bacterial Survival

Polymyxins are considered as the last resort antibiotics to treat infections caused by multidrug-resistant Gram negative pathogens. Pseudomonas aeruginosa is an opportunistic pathogen that causes various infections in humans. Proteins involved in lipopolysaccharide modification and maintaining inner and outer membrane integrities have been found to contribute to the bacterial resistance to polymyxins. Oligoribonuclease (Orn) is an exonuclease that regulates the homeostasis of intracellular (3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), thereby regulating the production of extracellular polysaccharide in P. aeruginosa . Previously, we demonstrated that Orn affects the bacterial resistance to fluoroquinolone, β-lactam and aminoglycoside antibiotics. In this study, we found that mutation of orn increased the bacterial survival following polymyxin B treatment in a wild type P. aeruginosa strain PA14. Overexpression of c-di-GMP degradation enzymes in the orn mutant reduced the bacterial survival. By using a fluorescence labeled polymyxin B, we found that mutation of orn increased the bacterial surface bound polymyxin B. Deletion of the Pel synthesis genes or treatment with a Pel hydrolase reduced the surface bound polymyxin B and bacterial survival. We further demonstrated that Pel binds to extracellular DNA (eDNA), which traps polymyxin B and thus protects the bacterial cells. Collectively, our results revealed a novel defense mechanism against polymyxin in P. aeruginosa .

scholarly journals Uji Aktivitas Antibakteri dari Ekstrak dan Fraksi Daging Buah Mangga Kasturi (Mangifera Casturi) terhadap Bakteri Pseudomonas Aeruginosa dan Bacillus Cereus

2021 ◽  
Vol 49 (2) ◽  
pp. 113-122
Author(s):  
Meliana Meliana ◽  
Sogandi Sogandi ◽  
Ekajayanti Kining
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Ethyl Acetate ◽  
Bacillus Cereus ◽  
Inhibitory Concentration ◽  
Mangifera Indica ◽  
Ethyl Acetate Fraction ◽  
Gas Chromatography Mass Spectrometry

Kasturi (Mangifera casturi) is a typical plant of South Kalimantan which has only been used for consumption because of its distinctive taste and aroma. Mangifera indica, which is in the same genus as Mangifera casturi, shows antioxidant, antibacterial, antifungal, and antidiarrheal activity, so it is suspected that this plant has the same activity. Crude methanol extract from the meat of Casturi mango was fractionated using n-hexane, ethyl acetate, and methanol-water. Testing for antibacterial activity and minimum inhibitory concentration (MIC) were carried out using the disk diffusion method (Kirby-Bauer). The positive control used was Chloramphenicol because it has an antibacterial range that is rather broad and the negative control used was 10% DMSO. The fraction that had the greatest antibacterial activity was the ethyl acetate fraction; with the formation of a clear zone of 7.98mm against Pseudomonas aeruginosa and 7.52mm against Bacillus cereus, with a minimum inhibitory concentration of 2mg/mL. The next test was a cell leakage analysis which revealed an increase in absorbance at MIC 1 and MIC 2. The Gas Chromatography – Mass Spectrometry (GC-MS) results from the ethyl acetate fraction revealed the presence of phenolic, flavonoid, and glycoide content, with the highest compound concentration of 5-Hydroxymethylfurfural. Keywords: Antibacterial, Extract, Ethyl acetate, fraction, Mangifera casturi Abstrak Kasturi (Mangifera casturi) merupakan tumbuhan khas Kalimantan Selatan yang selama ini hanya dimanfaatkan untuk dikonsumsi karena rasa dan aromanya yang khas. Mangifera indica yang masih satu genus dengan Mangifera casturi menunjukkan aktivitas antioksidan, antibakteri, antijamur, dan antidiare sehingga diduga tanaman ini memiliki aktivitas yang sama. Ekstrak kasar metanol daging buah mangga kasturi difraksinasi dengan menggunakan n-heksan, etil asetat, dan metanol-air. Pengujian aktivitas antibakteri dan kadar hambat minimum dilakukan dengan menggunakan metode difusi cakram (Kirby- Bauer). Kontrol positif yang digunakan adalah Chloramfenikol karena memiliki spektrum antibakteri yang cukup luas dan kontrol negatif yang digunakan adalah DMSO 10%. Fraksi yang memiliki aktivitas antibakteri terbesar pada penelitian ini adalah fraksi etil asetat dengan terbentuknya zona bening sebesar 7,98mm terhadap Pseudomonas aeruginosa dan 7,52mm terhadap Bacillus cereus dengan kadar hambat minimum 2mg/mL. Uji selanjutnya adalah uji kebocoran sel yang menyatakan adanya peningkatan absorbansi pada KHM 1 dan KHM 2. Hasil pemeriksaan Gas Chromatography – Mass Spectrometry (GCMS) dari fraksi etil asetat menyatakan adanya kandungan fenolik, flavonoid, dan glikosida dengan senyawa tertinggi yaitu 5-Hydroxymethylfurfural. Kata kunci: Antibakteri, Ekstrak, Etil asetat, Fraksi, Mangifera castur

scholarly journals Synthesis of CoFe 2 O 4 /BiOI Nanocomposite: Effects on Staphylococcus aureus, Escherichia coli, Pseudomonas Aeruginosa and Bacillus Cereus

2021 ◽  
Author(s):  
Davood Gheidari ◽  
Morteza Mehrdad ◽  
Saloomeh Maleki ◽  
Samanesadat Hosseini
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacillus Cereus ◽  
Antibacterial Properties ◽  
Limited Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inhibition Concentration ◽  
Resolution Mapping

Abstract With the increase of general knowledge and the advancement of science and technology, antibacterial substances were used more than antibiotics. In our current study, the antibacterial virtues of CFO/BiOI nanocomposite were investigated due to its high importance on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. MIC, MBC , Disk Diffusion and IC50 tests Cefalotin (CF), Amoxicillin (AMX), Gentamicin (GM), Trimethoprim-sulphamethoxazole (SXT) and Ceftriaxone (CRO) antibiotics in concentration 30W, 10i, 10t , 25h and 30 were used to find the antibacterial properties of the synthesized nanocomposite, respectively. For the synthesis of nanocomposites polyethylene glycol (PEG) and sulfonic acid was used as a solvent. It is noteworthy that the synthesis was performed by heat dissolution method without the presence of surfactant. Also, various techniques such as X-Ray Diffraction(XRD), Scanning Electron Microscope (SEM), High resolution mapping and Energy Dispersive X-ray spectroscopy (EDAX) have been used to determine the properties of produced nanocomposites. SEM test results showed that the formed nanoparticles were globular and their size was limited area of 22 to 34 nm. The results showed CFO / BiOI nanocomposite exhibits strong significant biological activity against Bacillus cereus. The results of MBC (Minimum Bactericidal Concentration) and MIC (Minimum Inhibition Concentration) tests for CFO/BiOI nanocomposites on bacteria were examined in the range of 0.12-0.48 mg/ml and 0.06 to 0.24 mg/ml respectively. According to the results, the minimum IC50 value was determined at a concentration of 0.061 mg/ml. On the other hand, the most resisting and susceptible bacteria in this method were Pseudomonas aeruginosa and Bacillus cereus, respectively. These findings are identical to those of a prior study on CoFe2O4 nanoparticles antibacterial properties. MBC of the nanocomposites, 50 µl from all the tubes that showed no obvious bacterial growth were distributed on BHI agar plates and incubated for 24 h at 37 ◦C. The MBC endpoint is defined as the lowest concentration which killed 98% of the bacterial population.

scholarly journals Elucidating the mechanism by which synthetic helper peptides sensitize Pseudomonas aeruginosa to multiple antibiotics

2021 ◽  
Vol 17 (9) ◽  
pp. e1009909
Author(s):  
Yushan Xia ◽  
Rubén Cebrián ◽  
Congjuan Xu ◽  
Anne de Jong ◽  
Weihui Wu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Treatment Strategies ◽  
Infection Model ◽  
Bacterial Cells ◽  
Membrane Phospholipids ◽  
Gram Negative ◽  
Atp Production ◽  
Rapid Spread ◽  
New Treatment ◽  
Multiple Antibiotics

The emergence and rapid spread of multi-drug resistant (MDR) bacteria pose a serious threat to global healthcare. There is an urgent need for new antibacterial substances or new treatment strategies to deal with the infections by MDR bacterial pathogens, especially the Gram-negative pathogens. In this study, we show that a number of synthetic cationic peptides display strong synergistic antimicrobial effects with multiple antibiotics against the Gram-negative pathogen Pseudomonas aeruginosa. We found that an all-D amino acid containing peptide called D-11 increases membrane permeability by attaching to LPS and membrane phospholipids, thereby facilitating the uptake of antibiotics. Subsequently, the peptide can dissipate the proton motive force (PMF) (reduce ATP production and inhibit the activity of efflux pumps), impairs the respiration chain, promote the production of reactive oxygen species (ROS) in bacterial cells and induce intracellular antibiotics accumulation, ultimately resulting in cell death. By using a P. aeruginosa abscess infection model, we demonstrate enhanced therapeutic efficacies of the combination of D-11 with various antibiotics. In addition, we found that the combination of D-11 and azithromycin enhanced the inhibition of biofilm formation and elimination of established biofilms. Our study provides a realistic treatment option for combining close-to-nature synthetic peptide adjuvants with existing antibiotics to combat infections caused by P. aeruginosa.

scholarly journals Efek Antimikroba Rhizophora Apiculata untuk Menghambat Pertumbuhan Bakteri

2019 ◽  
Vol 8 (2) ◽  
pp. 75-82
Author(s):  
Isnamurti Ciptaningrum ◽  
Reyhan Anjani Putri
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Protein Transport ◽  
Acid Synthesis ◽  
Complex Compounds ◽  
Google Scholar ◽  
Bacterial Cells ◽  
Cell Integrity ◽  
Membrane Function ◽  
Rhizophora Apiculata

Rhizophora apiculata, merupakan jenis tanaman mangrove yang tersebar melimpah di pesisir Indonesia. Populasi tanaman bakau di Indonesia mencapai 75% dari seluruh populasi bakau di dunia. Melimpahnya tanaman ini, belum dimanfaatkan secara optimal. Berdasarkan penelitian terdahulu, diketahui Rhizophora apiculata memiliki beberapa manfaat, salah satunya sebagai antibakteri. Zatantibakteri yang tekandung pada Rhizophora apiculatayaitu tannin, flavonoid dan saponin. Tannin bekerja mengadakan komplek hidrofobik dengan protein, menginaktivasi adhesi, enzim dan protein transport dinding sel, sehingga mengganggu pertumbuhan bakteri. Flavonoid bekerja menghambat sintesis asam nukleat, menghambat fungsi membran sel dan metabolisme energisertamencegah perkembangbiakan bakteri dengan membentuk senyawa kompleks protein ekstraseluler yang akan mengganggu integritas membran sel. Saponin bekerja dengan melisiskan sel bakteri. Berdasarkan penelitian yang telahdi lakukan, ekstrak daun, kulit batang dan akar Rhizophora apiculatadapat menghambat pertumbuhan bakteri Pseudomonas aeruginosa,Staphylococcus aureus, Streptococcus sp, dan Escherichia coli.Tujuandariliterature reviewiniadalah untuk mengetahui potensi Rhizophora apiculatasebagaiantibakteri. Metode yang digunakandalamartikeliniadalahpenelusuran artikel melalui database Google Scholar dan NCBI, lalu artikel dipilih dengan meninjau judul dan abstrak artikel, melibatkan 22 pustaka baik nasional maupun internasional.Hasil dari berbagai penelusuran yang dicantumkan dalam artikel ini untuk menunjukkan adanya potensiRhizophora apiculatasebagaiantibakteri.  Kata kunci: rhizophora apiculata, zatantibakteri, kandunganrhizophora apiculata   EFFECT ANTIMICROBACTERIAL RHIZOPHORA APICULTA FOR INHIBITS GROWTH OF BACTERIA   ABSTRACT Rhizophora apiculata is a type of mangrove that is spread abundantly in the coastal areas of Indonesia. The population of mangroves in Indonesia reaches 75% of the total mangrove population in the world. The abundance of mangroves in Indonesia has not been used optimally. Based on previous research, it is known that Rhizophora apiculata has several benefits, one of them is as an antibacterial. Anti-bacterial substance found in Rhizophora apiculata are tannin, flavonoid and saponin. Tannin works by holding a hydrophobic complex with protein, inactivates adhesion, enzymes and protein transport of cell walls, thereby disturb of bacterial growth. Flavonoids, work to inhibit nucleic acid synthesis, inhibit cells membrane function and inhibit energy metabolism and prevent bacterial proliferation by forming extracellular protein complex compounds that will disturb membrane cell integrity. Saponin as an antibacterial, works by lysis of bacterial cells. Based on several studies that have been done, leaf, bark and roots extracts of Rhizophora apiculata can inhibit the growth of the bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Escherichia coli. Rhizophora apiculata has an effect in inhabiting the growth of certain bacteria.The purpose of this literature review article is to get to know about the potency of Rhizophora apiculata as an antibacterial. The method used in this article uses a review of articles from Google Scholar and NCBI databases, then the article are selected by reviewing the article titles and abstracts, involving 22 libraries both national and international.The results of various articles included in this article are to show the potency of Rhizophora apiculata as an antibacterial.   Keywords: rhizophora apiculata, anti-bacterial substance, content of rhizophora apiculata

scholarly journals ANTIFUNGAL AND ANTIBACTERIAL ACTIVITY OF ALOE VERA PLANT EXTRACT

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
P Danish ◽  
Q Ali ◽  
MM Hafeez ◽  
A Malik
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Aspergillus Niger ◽  
Bacillus Megaterium ◽  
Aloe Vera ◽  
Water Soluble ◽  
Root Extract ◽  
Bacterial Strains ◽  
Zone Of Inhibition ◽  
Fungal Strains

Aloe vera is a well-known medicinal plant used in many therapeutic purposes. Naturally it is composed of many useful compounds that have ability to use for treatment of many diseases. The active compounds reported in this plant are saponins, sugar, enzymes, vitamins, aloesin, aloeemodin, aloin, acemannan aloemannan, aloeride, methylchromones, flavonoids, naftoquinones, sterols, minerals, anthraquinones, amino acids, lignin and salicylic acid and other different compounds including fat-soluble and water-soluble vitamins, enzymes, minerals, simple/complex sugars, organic acid and phenolic compounds. In this study aloe vera is used for antibacterial and antifulgal activity against different strains of bacteria and pathogenic fungal strains. Ethanol extract of Aloe vera leaves and roots is applied on these bacterial and fungal strains in different concentrations (15, 20, 25, 30µl). Bacillus cereus, Bacillus subtitis, Bacillus megaterium, Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and some other bacterial strains are used for this study. Escherichia coli and Agrobacterium tumefacins shows zone of inhibition around 18mm which consider as good result. Bacillus subtitis and Bacillus megaterium also shows good result around 16mm. Proteus mirabilis and Pseudomonas aeruginosa shows minimum zone of inhibition which is around 11mm. among all used fungal strains (fuserium oxysporum, Candida albicans, Aspergillus fumigatus, Aspergillus niger) fuserium oxysporum and Aspergillus niger shows excellent results around 19mm both against root extract and leaves extract.

scholarly journals POTENSI KULTUR CAMPURAN BAKTERI ENDOFIT SEBAGAI PEMACU PERTUMBUHAN BIBIT TANAMAN KARET

2014 ◽  
Vol 32 (2) ◽  
pp. 129 ◽  
Author(s):  
Umi Hidayati ◽  
Iswandi Anas Chaniago ◽  
Abdul Munif ◽  
Siswanto Siswanto ◽  
Dwi Andreas Santosa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Bacillus Cereus ◽  
Scanning Electron

Bakteri endofit adalah bakteri yang hidup dalam jaringan tanaman, dapat diisolasi melalui sterilisasi permukaan jaringan tanaman. Isolasi bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan sangat penting dilakukan. Pembuatan kultur campuran dari bakteri endofit diharapkan meningkatkan potensi dalam memacu pertumbuhan yang dapat meningkatkan kualitas bibit batang bawah tanaman karet. Penelitian ini dilakukan dengan tujuan mendapatkan kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Lima bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan yaitu Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, Brachybacterium paraconglomeratum LPD74, bacterium (bakteri tidak dikenal) LPD76, dan Providencia vermicola KPA38, diuji kompatibilitas untuk mendapatkan kultur campuran yang dapat meningkatkan pertumbuhan bibit batang bawah PB 260. Semua bakteri endofit terpilih kompatibel satu dengan yang lain. Aplikasi kultur campuran untuk meningkatkan pertumbuhan bibit batang bawah PB 260 memberikan hasil 2 kultur campuran terbaik. Kultur campuran 1 terdiri 2 spesies bakteri yaitu Brachybacterium paraconglomeratum LPD74 dan Providencia vermicola KPA38.  Kultur campuran 2 terdiri 3 spesies bakteri yaitu  Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, dan Brachybacterium paraconglomeratum LPD74. Bakteri endofit mampu masuk ke planlet bibit karet microcutting yang dibuktikan dengan Scanning Electron Microscopy. Diterima : 19 Mei 2014; Direvisi : 30 Mei 2014; Disetujui : 21 Juni 2014  How to Cite : Hidayati, U., Chaniago, I. A., Munif, A., Siswanto., & Santosa, D. A. (2014). Potensi kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Jurnal Penelitian Karet, 32(2), 129-138. Retrieved from http://ejournal.puslitkaret.co.id/index.php/jpk/article/view/159

scholarly journals Structure–function analysis of water-soluble inhibitors of the catalytic domain of exotoxin A from Pseudomonas aeruginosa

2005 ◽  
Vol 385 (3) ◽  
pp. 667-675 ◽  
Author(s):  
Susan P. YATES ◽  
Patricia L. TAYLOR ◽  
René JØRGENSEN ◽  
Dana FERRARIS ◽  
Jie ZHANG ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Diphtheria Toxin ◽  
Catalytic Domain ◽  
Competitive Inhibition ◽  
Function Analysis ◽  
Binding Pocket ◽  
Ring Structure ◽  
Water Soluble ◽  
Exotoxin A ◽  
Ic50 Values

The mono-ADPRT (mono-ADP-ribosyltransferase), Pseudomonas aeruginosa ETA (exotoxin A), catalyses the transfer of ADP-ribose from NAD+ to its protein substrate. A series of water-soluble compounds that structurally mimic the nicotinamide moiety of NAD+ was investigated for their inhibition of the catalytic domain of ETA. The importance of an amide locked into a hetero-ring structure and a core hetero-ring system that is planar was a trend evident by the IC50 values. Also, the weaker inhibitors have core ring structures that are less planar and thus more flexible. One of the most potent inhibitors, PJ34, was further characterized and shown to exhibit competitive inhibition with an inhibition constant Ki of 140 nM. We also report the crystal structure of the catalytic domain of ETA in complex with PJ34, the first example of a mono-ADPRT in complex with an inhibitor. The 2.1 Å (1 Å=0.1 nm) resolution structure revealed that PJ34 is bound within the nicotinamide-binding pocket and forms stabilizing hydrogen bonds with the main chain of Gly-441 and to the side-chain oxygen of Gln-485, a member of a proposed catalytic loop. Structural comparison of this inhibitor complex with diphtheria toxin (a mono-ADPRT) and with PARPs [poly(ADP-ribose) polymerases] shows similarity of the catalytic residues; however, a loop similar to that found in ETA is present in diphtheria toxin but not in PARP. The present study provides insight into the important features required for inhibitors that mimic NAD+ and their binding to the mono-ADPRT family of toxins.

Sign in / Sign up

Export Citation Format

Share Document