Killing Effect of Bacillus Velezensis FZB42 on a Xanthomonas Campestris pv. Campestris (Xcc) Strain Newly Isolated from Cabbage Brassica Oleracea Convar. Capitata (L.): A Metabolomic Study

The potential use of Bacillus velezensis FZB42 for biological control of various phytopathogens has been documented over the past few years, but its antagonistic interactions with xanthomonads has not been studied in detail. Novel aspects in this study consist of close observation of the death of Xanthomonas campestris pv. campestris cells in a co-culture with B. velezensis FZB42, and quantification of lipopeptides and a siderophore, bacillibactin, involved in the killing process. A new robust Xcc-SU isolate tolerating high concentrations of ferric ions was used. In a co-culture with the antagonist, the population of Xcc-SU was entirely destroyed within 24–48 h, depending on the number of antagonist cells used for inoculation. No inhibitory effect of Xcc-SU on B. velezensis was observed. Bacillibactin and lipopeptides (surfactin, fengycin, and bacillomycin) were present in the co-culture and the monoculture of B. velezensis. Except for bacillibactin, the maximum contents of lipopeptides were higher in the antagonist monoculture compared with the co-culture. Scanning electron microscopy showed that the death of Xcc-SU bacteria in co-culture was caused by cell lysis, leading to an enhanced occurrence of distorted cells and cell ghosts. Analysis by mass spectrometry showed four significant compounds, bacillibactin, surfactin, fengycin, and bacillomycin D amongst a total of 24 different forms detected in the co-culture supernatant: Different forms of surfactin and fengycin with variations in their side-chain length were also detected. These results demonstrate the ability of B. velezensis FZB42 to act as a potent antagonistic strain against Xcc.

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Potential Use of some Petal Extracts against Xanthomonas campestris pv. campestris

Our Nature ◽

10.3126/on.v9i1.5739 ◽

1970 ◽

Vol 9 (1) ◽

pp. 100-106

Author(s):

S.K. Bhardwaj ◽

S.K. Singla ◽

R.K. Bhardwaj

Keyword(s):

Xanthomonas Campestris ◽

Inhibitory Effect ◽

Tagetes Erecta ◽

Rosa Damascena ◽

Causal Organism ◽

Chrysanthemum Coronarium ◽

Lathyrus Odoratus ◽

Xanthomonas Campestris Pv Campestris ◽

Potential Use ◽

Anthocephalus Cadamba

The aqueous petal-extracts of 20 plants were screened by agar diffusion methods for their antibacterial activity against Xanthomonas campestris pv. campestris, a causal organism of black rot of cabbage and cauliflower. X. campestris pv. campestris was found most sensitive to the petal extracts of Tagetes erecta and Chrysanthemum coronarium. Some of the other plants such as Acacia fernesiana, Anthocephalus cadamba, Bombax malabaricum, Lathyrus odoratus, Rosa damascena and Thevetia nerifolia also showed the inhibitory effect against the test bacteria.DOI: http://dx.doi.org/10.3126/on.v9i1.5739

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Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2

International Journal of Molecular Sciences ◽

10.3390/ijms22189862 ◽

2021 ◽

Vol 22 (18) ◽

pp. 9862

Author(s):

Xudan Xu ◽

Tian Ye ◽

Wenping Zhang ◽

Tian Zhou ◽

Xiaofan Zhou ◽

...

Keyword(s):

Bacterial Infections ◽

Xanthomonas Campestris ◽

Cell Communication ◽

Maximal Activity ◽

Quorum Quenching ◽

Site Directed Mutagenesis ◽

Diffusible Signal Factor ◽

High Enzymatic Activity ◽

Xanthomonas Campestris Pv Campestris ◽

Potential Use

Quorum sensing (QS) is a microbial cell–cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.

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Kinetics of intestinal active transport of five neutral amino acids

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1965.208.4.593 ◽

1965 ◽

Vol 208 (4) ◽

pp. 593-600 ◽

Cited By ~ 53

Author(s):

D. M. Matthews ◽

Leonard Laster

Keyword(s):

Amino Acid ◽

Acid Concentration ◽

Mucosal Damage ◽

Inhibitory Effect ◽

Amino Acid Concentration ◽

Transport Rate ◽

Side Chain ◽

Initial Amino Acid ◽

High Concentrations ◽

Kinetics Of

Rates of transport against a concentration gradient by everted segments of hamster small intestine were determined for five monoaminomonocarboxylic acids. Values varied considerably from animal to animal. A graph of reciprocal of transport rate as a function of reciprocal of initial amino acid concentration revealed a linear relationship for each amino acid. Values for Kt, the concentration at which half-maximal transport is observed, diminished with increasing length of side chain for glycine, l-alanine, l-valine, and l-leucine. The Kt for α-aminoisobutyric acid was much higher than the others. Values for Vmax, the apparent limiting transport rate, decreased as chain length increased. With increasing initial amino acid concentration transport rate rose to a maximum and then declined. At concentrations producing this decline no gross mucosal damage was noted. The apparent inhibitory effect of these high concentrations was not a permanent one.

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Study on Transglucosylation Properties of Amylosucrase from Xanthomonas campestris pv. Campestris and Its Application in the Production of α-Arbutin

Catalysts ◽

10.3390/catal9010005 ◽

2018 ◽

Vol 9 (1) ◽

pp. 5 ◽

Cited By ~ 1

Author(s):

Chengyu Yang ◽

Weiming Fan ◽

Ruijie Zhang ◽

Jiping Shi ◽

Zorica Knežević-Jugović ◽

...

Keyword(s):

Xanthomonas Campestris ◽

Inhibitory Effect ◽

Industrial Applications ◽

Fed Batch ◽

Biotransformation Process ◽

Donor And Acceptor ◽

Prolonged Reaction Time ◽

Escherichia Coli Jm109 ◽

Skin Lightening ◽

Xanthomonas Campestris Pv Campestris

α-Arbutin (4-hydroquinone-α-D-glucopyranoside), an effective skin-lightening agent due to its considerable inhibitory effect on human tyrosinase activity, is widely used in the pharmaceutical and cosmetic industries. Recently, α-arbutin was prepared through transglucosylation of hydroquinone using microbial glycosyltransferases as catalysts. However, the low yield and prolonged reaction time of the biotransformation process of α-arbutin production limited its industrial application. In this work, an amylosucrase (ASase) from Xanthomonas campestris pv. campestris str. ATCC 33913 (XcAS) was expressed efficiently in Escherichia coli JM109. The catalytic property of the purified XcAS for the synthesis of α-arbutin was tested. The recombinant strain was applied for highly efficient synthesis of α-arbutin using sucrose and hydroquinone as glucosyl donor and acceptor, respectively. By optimizing the biotransformation conditions and applying a fed-batch strategy, the final production yield and conversion rate of α-arbutin reached 60.9 g/L and 95.5%, respectively, which is the highest reported yield by engineered strains. Compared to the highest reported value (<1.4 g/L/h), our productivity (7.6 g/L/h) was improved more than five-fold. This work represents an efficient and rapid method for α-arbutin production with potential industrial applications.

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In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646570 ◽

1989 ◽

Vol 61 (02) ◽

pp. 254-258 ◽

Cited By ~ 21

Author(s):

Margaret L Rand ◽

Peter L Gross ◽

Donna M Jakowec ◽

Marian A Packham ◽

J Fraser Mustard

Keyword(s):

Cyclic Amp ◽

Inhibitory Effect ◽

Rabbit Platelet ◽

Inhibitory Effects ◽

Low Concentrations ◽

Rabbit Platelets ◽

High Concentrations ◽

In Vitro Effects ◽

Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

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Inhibition of Platelet Function by Antiarrhythmic Drugs, Verapamil and Disopyramide

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657151 ◽

1982 ◽

Vol 47 (02) ◽

pp. 150-153 ◽

Cited By ~ 13

Author(s):

P Han ◽

C Boatwright ◽

N G Ardlie

Keyword(s):

Platelet Aggregation ◽

Platelet Function ◽

Antiarrhythmic Drugs ◽

Adenosine Diphosphate ◽

Inhibitory Effect ◽

Second Phase ◽

Ionophore A23187 ◽

High Concentrations ◽

Artery Disease

SummaryVarious cardiovascular drugs such as nitrates and propranolol, used in the treatment of coronary artery disease have been shown to have an antiplatelet effect. We have studied the in vitro effects of two antiarrhythmic drugs, verapamil and disopyramide, and have shown their inhibitory effect on platelet function. Verapamil, a calcium channel blocker, inhibited the second phase of platelet aggregation induced by adenosine diphosphate (ADP) and inhibited aggregation induced by collagen. Disopyramide similarly inhibited the second phase of platelet aggregation caused by ADP and aggregation induced by collagen. Either drug in synergism with propranolol inhibited ADP or collagen-induced platelet aggregation. Disopyramide at high concentrations inhibited arachidonic add whereas verapamil was without effect. Verapamil, but not disopyramide, inhibited aggregation induced by the ionophore A23187.

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Functional Involvement of Thrombospondin in Platelet Aggregation Induced by Low Versus High Concentrations of Thrombin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661464 ◽

1986 ◽

Vol 55 (01) ◽

pp. 136-142 ◽

Cited By ~ 4

Author(s):

K J Kao ◽

David M Shaut ◽

Paul A Klein

Keyword(s):

Platelet Aggregation ◽

Binding Sites ◽

Inhibitory Effect ◽

Activated Platelets ◽

Low Concentrations ◽

Platelet Binding ◽

Functional Involvement ◽

Thrombin Activation ◽

Platelet Aggregates ◽

High Concentrations

SummaryThrombospondin (TSP) is a major platelet secretory glycoprotein. Earlier studies of various investigators demonstrated that TSP is the endogenous platelet lectin and is responsible for the hemagglutinating activity expressed on formaldehyde-fixed thrombin-treated platelets. The direct effect of highly purified TSP on thrombin-induced platelet aggregation was studied. It was observed that aggregation of gel-filtered platelets induced by low concentrations of thrombin (≤0.05 U/ml) was progressively inhibited by increasing concentrations of exogenous TSP (≥60 μg/ml). However, inhibition of platelet aggregation by TSP was not observed when higher than 0.1 U/ml thrombin was used to activate platelets. To exclude the possibility that TSP inhibits platelet aggregation by affecting thrombin activation of platelets, three different approaches were utilized. First, by using a chromogenic substrate assay it was shown that TSP does not inhibit the proteolytic activity of thrombin. Second, thromboxane B2 synthesis by thrombin-stimulated platelets was not affected by exogenous TSP. Finally, electron microscopy of thrombin-induced platelet aggregates showed that platelets were activated by thrombin regardless of the presence or absence of exogenous TSP. The results indicate that high concentrations of exogenous TSP (≥60 μg/ml) directly interfere with interplatelet recognition among thrombin-activated platelets. This inhibitory effect of TSP can be neutralized by anti-TSP Fab. In addition, anti-TSP Fab directly inhibits platelet aggregation induced by a low (0.02 U/ml) but not by a high (0.1 U/ml) concentration of thrombin. In conclusion, our findings demonstrate that TSP is functionally important for platelet aggregation induced by low (≤0.05 U/ml) but not high (≥0.1 U/ml) concentrations of thrombin. High concentrations of exogenous TSP may univalently saturate all its platelet binding sites consequently interfering with TSP-crosslinking of thrombin-activated platelets.

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