scholarly journals Non-Lethal Effects of N-Acetylcysteine on Xylella fastidiosa Strain De Donno Biofilm Formation and Detachment

2019 ◽  
Vol 7 (12) ◽  
pp. 656 ◽  
Author(s):  
Cristina Cattò ◽  
Luca De Vincenti ◽  
Francesca Cappitelli ◽  
Giusy D’Attoma ◽  
Maria Saponari ◽  
...  

This study investigated in-vitro the non-lethal effects of N-acetylcysteine (NAC) on Xylella fastidiosa subspecies pauca strain De Donno (Xf-DD) biofilm. This strain was isolated from the olive trees affected by the olive quick decline syndrome in southern Italy. Xf-DD was first exposed to non-lethal concentrations of NAC from 0.05 to 1000 µM. Cell surface adhesion was dramatically reduced at 500 µM NAC (−47%), hence, this concentration was selected for investigating the effects of pre-, post- and co-treatments on biofilm physiology and structural development, oxidative homeostasis, and biofilm detachment. Even though 500 µM NAC reduced bacterial attachment to surfaces, compared to the control samples, it promoted Xf-DD biofilm formation by increasing: (i) biofilm biomass by up to 78% in the co-treatment, (ii) matrix polysaccharides production by up to 72% in the pre-treatment, and (iii) reactive oxygen species levels by 3.5-fold in the co-treatment. Xf-DD biofilm detachment without and with NAC was also investigated. The NAC treatment did not increase biofilm detachment, compared to the control samples. All these findings suggested that, at 500 µM, NAC diversified the phenotypes in Xf-DD biofilm, promoting biofilm formation (hyper-biofilm-forming phenotype) and discouraging biofilm detachment (hyper-attachment phenotype), while increasing oxidative stress level in the biofilm.

Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 633-638 ◽  
Author(s):  
L. L. R. Marques ◽  
H. Ceri ◽  
G. P. Manfio ◽  
D. M. Reid ◽  
M. E. Olson

Xylella fastidiosa colonizes the xylem of various host plants, causing economically important diseases such as Pierce's disease in grapevine and citrus variegated chlorosis (CVC) in sweet oranges. The aggregative nature of this bacterium has been extensively documented in the plant xylem and the insect's foregut. Structured communities of microbial aggregates enclosed in a self-produced polymeric matrix and attached to a surface are defined as biofilms. In this study, we characterized biofilm formation by X. fastidiosa through the use of a novel in vitro assay for studying biofilm growth in a potential mimic system of what might occur in planta. We used wood, a xylem rich material, as a surface for bacterial attachment and biofilm formation, under shear force. We demonstrated that X. fastidiosa strains isolated from various hosts formed biofilm on wood in this in vitro assay. Different biofilm morphology was detected, which seems to vary according to the strain tested and microenvironmental conditions analyzed. We observed that strains from different hosts could be grouped according to three parameters: biofilm morphology, the ability to form clumps in liquid culture, and the ability to attach to glass surfaces. We hypothesize that biofilm formation is likely a major virulence factor in diseases related to X. fastidiosa, bringing a new perspective for disease treatment.


2019 ◽  
Author(s):  
Valeria Scala ◽  
Nicoletta Pucci ◽  
Manuel Salustri ◽  
Vanessa Modesti ◽  
Alessia L’Aurora ◽  
...  

AbstractXylella fastidiosa is an insect vector-transmitted bacterial plant pathogen associated with severe diseases in a wide range of plants. In last decades, X. fastidiosa was detected in several European countries. Among X. fastidiosa subspecies, here we study X. fastidiosa subsp. pauca associated with the Olive Quick Decline Syndrome (OQDS) causing severe losses in Southern Italy. First, we collected Olea europaea L. (cv. Ogliarola salentina) samples in groves located in infected zones and uninfected zones. Secondly, the untargeted LC-TOF analysis of the lipid profiles of OQDS positive (+) and negative (-) plants showed a significant clustering of OQDS+ samples apart from OQDS-ones. Thirdly, using HPLC-MS/MS targeted methods and chemometric analysis, we identified a shortlist of 10 lipids significantly different in the infected versus healthy samples. Last, we observed a clear impact on X. fastidiosa subsp. pauca growth and biofilm formation in vitro liquid cultures supplemented with these compounds.Considering that growth and biofilm formation are primary ways by which X. fastidiosa causes disease, our results demonstrate that lipids produced as part of the plant’s immune response can exacerbate the disease. This is reminiscent of an allergic reaction in animal systems, offering the depression of plant immune response as a potential strategy for OQDS treatment.Author summaryGlobal trade and climate change are re-shaping the distribution map of pandemic pathogens. One major emerging concern is Xylella fastidiosa, a tropical bacterium recently introduced into Europe from America. Its impact has been dramatic: in the last 5-years only, Olive Quick Decline Syndrome (OQDS) has caused thousands of 200 years old olive trees to be felled in the southern Italy. Xylella fastidiosa through a tight coordination of the adherent biofilm and the planktonic states, invades the host systemically. The planktonic phase is correlated to low cell density and vessel colonization. Increase in cell density triggers a quorum sensing system based on cis 2-enoic fatty acids—diffusible signalling factors (DSF) that promote stickiness and biofilm. Xylem vessels are occluded by the combined effect of bacterial biofilm and plant defences (e.g. tyloses). This study provides novel insight on how X. fastidiosa subsp. pauca biology relates to the Olive Quick Decline Syndrome. We found that some class of lipids increase their amount in the infected olive tree. These lipid entities, provided to X. fastidiosa subsp. pauca behave as hormone-like molecules: modulating the dual phase, e.g. planktonic versus biofilm. Probably, part of these lipids represents a reaction of the plant to the bacterial contamination.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Zahra Farshadzadeh ◽  
Maryam Pourhajibagher ◽  
Behrouz Taheri ◽  
Alireza Ekrami ◽  
Mohammad Hossein Modarressi ◽  
...  

Abstract Background The global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii. Methods After determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed. Results The bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L. Conclusions Results of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.


Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 724-730 ◽  
Author(s):  
Qing Ge ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente

Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes disease in many crops worldwide. Copper (Cu) is an antimicrobial agent widely used on X. fastidiosa hosts to control other diseases. Although the effects of Cu for control of foliar pathogens are well known, it is less studied on xylem-colonizing pathogens. Previous results from our group showed that low concentrations of CuSO4 increased biofilm formation, whereas high concentrations inhibited biofilm formation and growth in vitro. In this study, we conducted in planta experiments to determine the influence of Cu in X. fastidiosa infection using tobacco as a model. X. fastidiosa-infected and noninfected plants were watered with tap water or with water supplemented with 4 mM or 8 mM of CuSO4. Symptom progression was assessed, and sap and leaf ionome analysis was performed by inductively coupled plasma with optical emission spectroscopy. Cu uptake was confirmed by increased concentrations of Cu in the sap of plants treated with CuSO4-amended water. Leaf scorch symptoms in Cu-supplemented plants showed a trend toward more severe at later time points. Quantification of total and viable X. fastidiosa in planta indicated that CuSO4-amended treatments did not inhibit but slightly increased the growth of X. fastidiosa. Cu in sap was in the range of concentrations that promote X. fastidiosa biofilm formation according to our previous in vitro study. Based on these results, we proposed that the plant Cu homeostasis machinery controls the level of Cu in the xylem, preventing it from becoming elevated to a level that would lead to bacterial inhibition.


2004 ◽  
Vol 237 (2) ◽  
pp. 341-353 ◽  
Author(s):  
Alessandra A. Souza ◽  
Marco A. Takita ◽  
Helvécio D. Coletta-Filho ◽  
Camila Caldana ◽  
Giane M. Yanai ◽  
...  

2018 ◽  
Vol 38 (3) ◽  
pp. e12456 ◽  
Author(s):  
Nor Ainy Mahyudin ◽  
Noor Ifatul Hanim Mat Daud ◽  
Nor-Khaizura Mahmud Ab Rashid ◽  
Belal J. Muhialdin ◽  
Nazamid Saari ◽  
...  

2010 ◽  
Vol 23 (10) ◽  
pp. 1356-1363 ◽  
Author(s):  
Subhadeep Chatterjee ◽  
Nabil Killiny ◽  
Rodrigo P. P. Almeida ◽  
Steven E. Lindow

Xylella fastidiosa must coordinately regulate a variety of traits contributing to biofilm formation, host plant and vector colonization, and transmission between plants. Traits such as production of extracellular polysaccharides (EPS), adhesins, extracellular enzymes, and pili are expressed in a cell-density-dependent fashion mediated by a cell-to-cell signaling system involving a fatty acid diffusible signaling factor (DSF). The expression of gene PD0279 (which has a GGDEF domain) is downregulated in the presence of DSF and may be involved in intracellular signaling by modulating the levels of cyclic di-GMP. PD0279, designated cyclic di-GMP synthase A (cgsA), is required for biofilm formation, plant virulence, and vector transmission. cgsA mutants exhibited a hyperadhesive phenotype in vitro and overexpressed gumJ, hxfA, hxfB, xadA, and fimA, which promote attachment of cells to surfaces and, hence, biofilm formation. The mutants were greatly reduced in virulence to grape albeit still transmissible by insect vectors, although at a reduced level compared with transmission rates of the wild-type strain, despite the fact that similar numbers of cells of the cgsA mutant were acquired by the insects from infected plants. High levels of EPS were measured in cgsA mutants compared with wild-type strains, and scanning electron microscopy analysis also revealed a thicker amorphous layer surrounding the mutants. Overexpression of cgsA in a cgsA-complemented mutant conferred the opposite phenotypes in vitro. These results suggest that decreases of cyclic di-GMP result from the accumulation of DSF as cell density increases, leading to a phenotypic transition from a planktonic state capable of colonizing host plants to an adhesive state that is insect transmissible.


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