scholarly journals Evolution of the C30 Carotenoid Synthase CrtM for Function in a C40 Pathway

2002 ◽  
Vol 184 (23) ◽  
pp. 6690-6699 ◽  
Author(s):  
Daisuke Umeno ◽  
Alexander V. Tobias ◽  
Frances H. Arnold
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Substrate Specificity ◽  
Significant Variation ◽  
The Other ◽  
Biosynthetic Pathways ◽  
Product Range

ABSTRACT The C30 carotene synthase CrtM from Staphylococcus aureus and the C40 carotene synthase CrtB from Erwinia uredovora were swapped into their respective foreign C40 and C30 biosynthetic pathways (heterologously expressed in Escherichia coli) and evaluated for function. Each displayed negligible ability to synthesize the natural carotenoid product of the other. After one round of mutagenesis and screening, we isolated 116 variants of CrtM able to synthesize C40 carotenoids. In contrast, we failed to find a single variant of CrtB with detectable C30 activity. Subsequent analysis revealed that the best CrtM mutants performed comparably to CrtB in an in vivo C40 pathway. These mutants showed significant variation in performance in their original C30 pathway, indicating the emergence of enzymes with broadened substrate specificity as well as those with shifted specificity. We discovered that Phe 26 alone determines the specificity of CrtM. The plasticity of CrtM with respect to its substrate and product range highlights the potential for creating further new carotenoid backbone structures.

scholarly journals Induction of the Galactose Enzymes in Escherichia coli Is Independent of the C-1-Hydroxyl Optical Configuration of the Inducer d-Galactose

2008 ◽  
Vol 190 (24) ◽  
pp. 7932-7938 ◽  
Author(s):  
Sang Jun Lee ◽  
Dale E. A. Lewis ◽  
Sankar Adhya
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Carbon Source ◽  
The Other ◽  
Biosynthetic Pathways ◽  
In Vitro Experiments ◽  
Metabolizing Enzymes ◽  
Optical Configuration

ABSTRACT The two optical forms of aldohexose galactose differing at the C-1 position, α-d-galactose and β-d-galactose, are widespread in nature. The two anomers also occur in di- and polysaccharides, as well as in glycoconjugates. The anomeric form of d-galactose, when present in complex carbohydrates, e.g., cell wall, glycoproteins, and glycolipids, is specific. Their interconversion occurs as monomers and is effected by the enzyme mutarotase (aldose-1-epimerase). Mutarotase and other d-galactose-metabolizing enzymes are coded by genes that constitute an operon in Escherichia coli. The operon is repressed by the repressor GalR and induced by d-galactose. Since, depending on the carbon source during growth, the cell can make only one of the two anomers of d-galactose, the cell must also convert one anomer to the other for use in specific biosynthetic pathways. Thus, it is imperative that induction of the gal operon, specifically the mutarotase, be achievable by either anomer of d-galactose. Here we report in vivo and in vitro experiments showing that both α-d-galactose and β-d-galactose are capable of inducing transcription of the gal operon with equal efficiency and kinetics. Whereas all substitutions at the C-1 position in the α configuration inactivate the induction capacity of the sugar, the effect of substitutions in the β configuration varies depending upon the nature of the substitution; methyl and phenyl derivatives induce weakly, but the glucosyl derivative does not.

Garlic Extract (Allium sativum L.) Effectively Inhibits Staphylococcus aureus and Escherichia coli by Invitro Test

2020 ◽  
Vol 2 (2) ◽  
pp. 61-68
Author(s):  
Agnina Listya Anggraini ◽  
Ratih Dewi Dwiyanti ◽  
Anny Thuraidah
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Allium Sativum ◽  
Antibacterial Properties ◽  
Herbal Medicines ◽  
Garlic Extract ◽  
Dilution Method ◽  
Initial Stage

Infection is a disease caused by the presence of pathogenic microbes, including Staphylococcus aureus and Escherichia coli. Garlic (Allium sativum L.) has chemical contents such as allicin, alkaloids, flavonoids, saponins, tannins, and steroids, which can function as an antibacterial against Staphylococcus aureus and Escherichia coli. This study aims to determine the antibacterial properties of garlic extract powder against Staphylococcus aureus and Escherichia coli. This research is the initial stage of the development of herbal medicines to treat Staphylococcus aureus and Escherichia coli infections. The antibacterial activity test was carried out by the liquid dilution method. The concentrations used were 30 mg/mL, 40 mg/mL, 50 mg/mL, 60 mg/mL and 70 mg/mL. The results showed that the Minimum Inhibitory Concentration (MIC) against Staphylococcus aureus and Escherichia coli was 40 mg/mL and 50 mg / mL. Minimum Bactericidal Concentration (MBC) results for Staphylococcus aureus and Escherichia coli are 50 mg/mL and 70 mg/mL. Based on the Simple Linear Regression test, the R2 value of Staphylococcus aureus and Escherichia coli is 0.545 and 0.785, so it can be concluded that there is an effect of garlic extract powder on the growth of Staphylococcus aureus and Escherichia coli by 54.5% and 78.5%. Garlic (Allium sativum L.) extract powder has potential as herbal medicine against bacterial infections but requires further research to determine its effect in vivo.

scholarly journals In vitro and in vivo evaluation of antibacterial activity of Bridelia ferruginea extracts on some clinical isolates

2018 ◽  
Vol 7 (4) ◽  
pp. 392-398
Author(s):  
B.T Yunana ◽  
◽  
B. B Bukar ◽  
J. C Aguiyi ◽  
◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bark Extract ◽  
Root Extract ◽  
Root Bark ◽  
Zone Of Inhibition ◽  
Bridelia Ferruginea

The ethanol extracts of root, bark and leaf of Bridelia ferruginea was investigated for antibacterial activity against clinical isolate of Staphylococcus aureus and Escherichia coli. The extracts had significant antibacterial activity in vitro at concentration of 25 mg/ml, 50 mg/ml, 100 mg/ml and 200 mg/ml and in vivo at dose of 50 mg/kg and 100 mg/kg. The root extract in vitro had the highest zone of inhibition, followed by the bark extract for both Staphylococcus aureus and Escherichia coli. The concentration of 200 mg/ml had the highest zone of inhibition in vitro. The minimum inhibitory concentration (MIC) showed a decreasing inhibitory effect of the plant extracts for both Staphylococcus aureus and Escherichia coli as the concentration decreases with root having 3.125 mg/ml, bark having 6.25 mg/ml and leaf having 25 mg/ml for Staphylococcus aureus and Escherichia coli. Likewise, the minimum bactericidal concentration (MBC) showed decreasing bactericide effects with decrease concentration with root having 12.5 mg/ml, bark having 12.5 mg/ml and leaf having 25 mg/ml for Escherichia coli while root had 6.25mg/ml, bark had 12.5mg/ml and leaf had 25mg/ml for Staphylococcus aureus. The in vivo investigation showed that the root and bark extract exhibited antibacterial activity on both Staphylococcus aureus and Escherichia coli at doses of 100mg/kg and 50mg/kg; the root extract had higher activity than the bark and root/bark combined. The dose of 100 mg/kg had the highest colonies reduction for Staphylococcus aureus and Escherichia coli in vivo. Preliminary phytochemical screening of root, bark and leaves of Bridelia ferruginea revealed the presence of tannins, flavonoids, carbohydrates, cardiac glycoside (root, bark and leaves), saponins (root and bark). The presence of tannins, saponins, flavonoid, cardiac glycoside and carbohydrate in the bark and root extracts of the plant indicates that the bark and root extracts were pharmacological importance

scholarly journals Hypochlorite-Activated Fluorescence Emission and Antibacterial Activities of Imidazole Derivatives for Biological Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Thanh Chung Pham ◽  
Van-Nghia Nguyen ◽  
Yeonghwan Choi ◽  
Dongwon Kim ◽  
Ok-Sang Jung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Antibacterial Activities ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Fluorogenic Probe ◽  
High Fluorescence

The ability to detect hypochlorite (HOCl/ClO−) in vivo is of great importance to identify and visualize infection. Here, we report the use of imidazoline-2-thione (R1SR2) probes, which act to both sense ClO− and kill bacteria. The N2C=S moieties can recognize ClO− among various typical reactive oxygen species (ROS) and turn into imidazolium moieties (R1IR2) via desulfurization. This was observed through UV–vis absorption and fluorescence emission spectroscopy, with a high fluorescence emission quantum yield (ՓF = 43–99%) and large Stokes shift (∆v∼115 nm). Furthermore, the DIM probe, which was prepared by treating the DSM probe with ClO−, also displayed antibacterial efficacy toward not only Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) but also methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum ß-lactamase–producing Escherichia coli (ESBL-EC), that is, antibiotic-resistant bacteria. These results suggest that the DSM probe has great potential to carry out the dual roles of a fluorogenic probe and killer of bacteria.

scholarly journals Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae)

2020 ◽  
Vol 151 ◽  
pp. 15550-15558
Author(s):  
Amégninou Agban ◽  
Yao Hoekou ◽  
Passimna Pissang ◽  
Tchadjobo Tchacondo ◽  
Komlan Batawila
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Aqueous Extract ◽  
E Coli ◽  
Toxicological Studies ◽  
Jatropha Multifida

Objectif : L’objectif de ce travail était d’évaluer in vitro l’activité antimicrobienne des extraits de feuilles et tige de Jatropha multifida sur la croissance de Candida albicans, Escherichia coli et Staphylococcus aureus, puis d’évaluer in vivo la toxicité de cette plante. Méthodologie et résultats : Les méthodes de diffusion en milieu gélosé et de microdilution en milieu liquide ont été utilisées pour évaluer l’effet antimicrobien. Une étude en subaigüe était réalisée afin d’explorer les effets toxiques de l’extrait aqueux des feuilles. Les résultats des tests antimicrobiens montrent une activité des extraits de feuilles et tige de J. multifida sur la croissance des souches utilisées avec des diamètres de zones d’inhibition allant de 8 à 25 mm et des concentrations minimales inhibitrices (CMI) variant de 0,039 mg/mL à 1,25 mg/mL à l’exception des souches de E. coli qui sont résistantes aux extraits de la tige. L’administration en subaigüe de l’extrait aqueux des feuilles de J. multifida à la dose de 600 mg/kg entraîne une perte significative de poids chez les souris. Conclusion et applications des résultats : Les extraits aqueux, éthanolique et hydroéthanolique des feuilles et tige de J. multifida possèdent d’activité antimicrobienne et pourraient être utilisés dans le traitement des Candidoses à C. albicans et des infections à S. aureus. Mais l’essai de toxicité subaigüe montre que l’extrait aqueux de la plante serait toxique. Des études toxicologiques approfondies restent donc nécessaires sur ces extraits afin de mieux élucider leur inocuité. Mots-clés : Jatropha multifida, extraits de feuilles et de tige, activités antifongique et antibactérienne, toxicité. Agban et al., J. Appl. Biosci. 2020 Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae) 15551 Evaluation of antimicrobial potential and toxicity of Jatropha multifida Linn, (Euphorbiaceae) extracts ABSTRACT Objective: The objective of this study was to evaluate in vitro the antimicrobial activity of leaves and stem of Jatropha multifida extracts against Candida albicans, Escherichia coli and Staphylococcus aureus, and then to evaluate in vivo the toxicity of this plant. Methodology and Results: The agar well-diffusion and the NCCLS broth microdilution methods were used to assess the antimicrobial effect. A subacute study was carried out to explore the toxic effects of the aqueous extract of the leaves. The results of the antimicrobial tests show an activity of the extracts of leaves and stems of J. multifida on the growth of the strains used with diameters of inhibitory zones ranging from 8 to 25 mm and minimum inhibitory concentrations (MIC) varying from 0.039 mg/mL to 1.25 mg/mL exception E. coli strains which are resistant to extracts from the stem. Subacute administration of the aqueous extract of the leaves of J. multifida at a dose of 600 mg/kg leads to a significant loss of weight in the mice. Conclusion and application of findings : The aqueous, ethanolic and hydroethanolic extracts of the leaves and stem of J. multifida have antimicrobial activity and could be used in the treatment of Candidiasis and bacterial infections due respectively to C. albicans and S. aureus. But the subacute toxicity test shows that the aqueous extract of the plant would be toxic. Extensive toxicological studies therefore remain necessary on these extracts in order to better elucidate their safety. Keywords: Jatropha multifida extracts of leaves and stem, antifungal and antibacterial activities, toxicity

POTENCIAL ANTIBACTERIANO IN VITRO E TOXICOLÓGICO IN VIVO DAS FOLHAS DO JAMBO VERMELHO (Syzygium malaccensis, Myrtaceae) FRENTE A ZEBRAFISH (D. rerio) ADULTO

2021 ◽  
Author(s):  
Fernando E. T. Cunha ◽  
Maria I. C. Ferreira ◽  
Rafael S. Cruz ◽  
Maria J. G. Ferreira ◽  
Clarissa M. Aquino ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Danio Rerio ◽  
Salmonella Enteritidis

Este trabalho reporta o potencial antibacteriano in vitro e toxicológico in vivo das folhas do jambo (Syzygium malaccense) frente a zebrafish (Danio rerio) adulto (ZFa). As folhas de jambo foram submetidas a desidratação (35 ± 2°C) por 24 horas, trituração e posterior extração de metabólitos por decocção, infusão e maceração com água destilada. Os extratos obtidos foram liofilizados e submetidos a análise de atividade antibacteriana in vitro frente a Gram-negativas (Escherichia coli ATCC 25922, Salmonella Enteritidis IAL 1132) e Gram-positivas (Listeria monocytogenes ATCC 19115 e Staphylococcus aureus ATCC 27664), bem como ao potencial toxicológico in vivo frente ao ZFa. O extrato obtido por infusão se mostrou mais promissor, pois apresentou concentração mínima bactericida (CMB) e concentração mínima inibitória (CMI) com maior potencial frente às gram- positivas (CMB - 6,25 e CMI - 6,25 mg/ml), bem como às gram-negativas (CMB - 25,0 e 3,125 e CMI - 3,125 mg/ml). Todos os extratos testados não se mostraram tóxicos frente ao zebrafish adulto e não alteraram o sistema locomotor dos mesmos. Desta forma, conclui-se que o extrato aquoso das folhas do jambo vermelho (Syzygium malaccense) obtido por infusão é seguro e pode ser utilizado como conservante natural com maior ação antibacteriana. Este trabalho nos conduz a novos estudos de isolamento e caracterização de princípios bioativos.

Growth and Death of Selected Microorganisms in Ultrafiltered Milk

1986 ◽  
Vol 49 (3) ◽  
pp. 233-235 ◽  
Author(s):  
PATRICIA HAGGERTY ◽  
NORMAN N. POTTER
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Skim Milk ◽  
Laboratory Scale ◽  
The Other ◽  
Streptococcus Faecalis ◽  
E Coli ◽  
Milk Samples ◽  
D Values ◽  
D Value

Studies were made to compare the growth and death of Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in skim milk concentrated by ultrafiltration to that in unconcentrated skim milk. Skim milk was volume concentrated to 2× in laboratory-scale stirred UF cells. Behavior of the organisms was analyzed in four inoculated milk samples: 2× retentate, 1× water-diluted retentate, milk equivalent (retentate plus permeate) and unconcentrated skim milk. Growth of each organism and of total aerobes did not vary in the four milk samples at either 7 or 13°C. For S. faecalis and E. coli, D-values for samples heated to 62.7°C did not significantly differ in the four milk samples (p>0.01). The D-value of S. aureus in water-diluted retentate was slightly but significantly lower than those in the other three milk samples (p<0.01), possibly due to the lowered lactose level in this sample.

scholarly journals Relationship between Susceptibility to Daptomycin In Vitro and Activity In Vivo in a Rabbit Model of Aortic Valve Endocarditis

2009 ◽  
Vol 53 (4) ◽  
pp. 1463-1467 ◽  
Author(s):  
H. F. Chambers ◽  
L. Basuino ◽  
B. A. Diep ◽  
J. Steenbergen ◽  
S. Zhang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Body Weight ◽  
Aortic Valve ◽  
Rabbit Model ◽  
Dual Infection ◽  
Survival Advantage ◽  
The Other ◽  
Infection Model

ABSTRACT Daptomycin is approved for treatment of Staphylococcus aureus bacteremia and right-sided endocarditis. Increases in daptomycin MICs have been associated with failure. A rabbit model of aortic valve endocarditis was used to determine whether MIC correlates with activity in vivo and whether a higher daptomycin dose can improve efficacy. Two related clinical S. aureus strains, one with a daptomycin MIC of 0.5 μg/ml and the other with a MIC of 2 μg/ml, were used to establish aortic valve endocarditis in rabbits. Daptomycin was administered once a day for 4 days at 12 mg/kg of body weight or 18 mg/kg to simulate doses in humans of 6 mg/kg and 10 mg/kg, respectively. Endocardial vegetations, spleens, and kidneys were harvested and quantitatively cultured. The strain with a MIC of 2 μg/ml had a survival advantage over the strain with a MIC of 0.5 μg/ml with >100 times more organisms of the former in endocardial vegetations at the 12-mg/kg dose in a dual-infection model. Both the 12-mg/kg dose and the 18-mg/kg dose completely eradicated the strain with a MIC of 0.5 from vegetations, spleens, and kidneys. The 12-mg/kg dose was ineffective against the strain with a MIC of 2 in vegetations; the 18-mg/kg dose produced a reduction of 3 log10 units in CFU in vegetations compared to the controls, although in no rabbit were organisms completely eliminated. Increasing the dose of daptomycin may improve its efficacy for infections caused by strains with reduced daptomycin susceptibility.

scholarly journals Occurrence of Two 5-Aminolevulinate Biosynthetic Pathways in Streptomyces nodosus subsp. asukaensis Is Linked with the Production of Asukamycin

2006 ◽  
Vol 188 (14) ◽  
pp. 5113-5123 ◽  
Author(s):  
Miroslav Petříček ◽  
Kateřina Petříčková ◽  
Libor Havlíček ◽  
Jürgen Felsberg
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Aminolevulinic Acid ◽  
Streptomyces Coelicolor ◽  
Biosynthetic Pathways ◽  
Tetrapyrrole Biosynthesis ◽  
Streptomyces Nodosus ◽  
Encoding Gene

ABSTRACT We report the results of cloning genes for two key biosynthetic enzymes of different 5-aminolevulinic acid (ALA) biosynthetic routes from Streptomyces. The genes encode the glutamyl-tRNAGlu reductase (GluTR) of the C5 pathway and the ALA synthase (ALAS) of the Shemin pathway. While Streptomyces coelicolor A3(2) synthesizes ALA via the C5 route, both pathways are operational in Streptomyces nodosus subsp. asukaensis, a producer of asukamycin. In this strain, the C5 route produces ALA for tetrapyrrole biosynthesis; the ALA formed by the Shemin pathway serves as a precursor of the 2-amino-3-hydroxycyclopent-2-enone moiety (C5N unit), an antibiotic component. The growth of S. nodosus and S. coelicolor strains deficient in the GluTR genes (gtr) is strictly dependent on ALA or heme supplementation, whereas the defect in the ALAS-encoding gene (hemA-asuA) abolishes the asukamycin production in S. nodosus. The recombinant hemA-asuA gene was expressed in Escherichia coli and in Streptomyces, and the encoded enzyme activity was demonstrated both in vivo and in vitro. The hemA-asuA gene is situated within a putative cluster of asukamycin biosynthetic genes. This is the first report about the cloning of genes for two different ALA biosynthetic routes from a single bacterium.

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