scholarly journals Characterization of Biofilm Formation by Xylella fastidiosa In Vitro

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
Keyword(s):  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
In Vitro Assay ◽  
Bacterial Attachment ◽  
In Planta ◽  
Biofilm Growth ◽  
Vitro Assay ◽  
Rich Material ◽  
New Perspective

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.

scholarly journals Copper Supplementation in Watering Solution Reaches the Xylem But Does Not Protect Tobacco Plants Against Xylella fastidiosa Infection

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 724-730 ◽  
Author(s):  
Qing Ge ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente
Keyword(s):  
Biofilm Formation ◽  
Inductively Coupled Plasma ◽  
Tap Water ◽  
Xylella Fastidiosa ◽  
In Vitro Study ◽  
Optical Emission ◽  
In Planta ◽  
Inductively Coupled ◽  
High Concentrations

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.

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 ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
Bacterial Attachment ◽  
Structural Development ◽  
Lethal Effects ◽  
Biofilm Detachment ◽  
Pre Treatment ◽  
Olive Quick Decline Syndrome ◽  
Control Samples

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.

scholarly journals The Effect of Various pH Medium on the Secondary Metabollites Production from Trichoderma harzianum T10 to Control Damping Off on Cucumber Seedlings

2020 ◽  
Vol 3 (2) ◽  
pp. 65
Author(s):  
Nur Chalimah ◽  
Loekas Soesanto ◽  
Woro Sri Suharti
Keyword(s):  
Secondary Metabolites ◽  
Trichoderma Harzianum ◽  
Disease Incidence ◽  
In Vitro Assay ◽  
Cucumber Seedling ◽  
Damping Off ◽  
In Planta ◽  
Vitro Assay ◽  
Cucumber Seedlings

Damping-off is one of the main diseases in cucumber seedlings caused by Pythium sp. Secondary metabolites of Trichoderma harzianum T10 can conduct the control of the disease. The pH of the medium influences the production of secondary metabolites. The research aimed to determine the effective pH medium on production of T. harzianum T10 secondary metabolites, and the effect of the T. harzianum T10 secondary metabolites application in damping-off disease control also to the growth of cucumber seedling. The research was consist of two steps; 1) in vitro assay with various pH levels 5; 3; 3.5; 4; 4.5; 5.5; 6; 6.5; and 7, 2) In planta treatments consisted of control, fungicide (Mancozeb), secondary metabolites in pH 5 and 5.5 with the concentration of 5, 10 and 15% each. The research showed that: 1) the effective pH medium for the production of T. harzianum T10 secondary metabolites was 5 and 5.5. 2) application of the T. harzianum T10 secondary metabolites on pH 5 and 5.5 with a concentration of 5, 10, and 15% could decrease the disease incidence and support cucumber seedling growth.

Vesicular Lipid Nanoparticles (Liposomes) for the Treatment of Medical Device Infections

2011 ◽  
Vol 1316 ◽  
Author(s):  
Erik Taylor ◽  
Anubhav Kaviratna ◽  
Rinti Banerjee ◽  
Thomas J. Webster
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Lipid Nanoparticles ◽  
In Vitro Assay ◽  
Silver Sulfadiazine ◽  
Human Pathogens ◽  
Vitro Assay ◽  
First Time ◽  
Better Than

AbstractLiposomes (a phospholipid bi-layer which can be formulated to contain drugs or other reagents) composed of endogenous phospholipid dipalmitoylphosphatidylcholine (DPPC) in combination with dioleoylphosphatidylethanolamine (DOPE), lauric acid, and silver sulfadiazine were made into vesicular nanoparticles in this study using an optimized extrusion technique. Liposomes were then tested for antibacterial activity against a range of bacteria species including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Bacillus subtilis (all are relevant human pathogens known to infect implants) and were also challenged to prevent the growth of adherent biofilms (a robust slimy extracellular matrix) through an in vitro assay relevant to device related infections. It was found that all liposomes reduced bacterial growth, and, most importantly, liposomes containing DPPC and DOPE reduced biofilm formation better than the commercially available antibiotic silver sulfadiazine. These results indicated for the first time that such liposomes might be a better approach to prevent device related infections.

In Vitro Assay of Platelet Adhesiveness with Washed and Tanned Human Red Cells

1968 ◽  
Vol 20 (03/04) ◽  
pp. 384-396 ◽  
Author(s):  
G Zbinden ◽  
S Tomlin
Keyword(s):  
Platelet Adhesion ◽  
Sodium Citrate ◽  
Blood Platelets ◽  
In Vitro Assay ◽  
Red Cells ◽  
Platelet Adhesiveness ◽  
Vitro Assay ◽  
In Vitro System ◽  
Human Red Cells

SummaryAn in vitro system is described in which adhesion of blood platelets to washed and tannic acid-treated red cells was assayed quantitatively by microscopic observation. ADP, epinephrine and TAME produced a reversible increase in platelet adhesiveness which was antagonized by AMP. With Evans blue, polyanetholsulfonate, phthalanilide NSC 38280, thrombin and heparin at concentrations above 1-4 u/ml the increase was irreversible. The ADP-induced increase in adhesiveness was inhibited by sodium citrate, EDTA, AMP, ATP and N-ethylmaleimide. EDTA, AMP and the SH-blocker N-ethylmaleimide also reduced spontaneous platelet adhesion to red cells. No significant effects were observed with adenosine, phenprocoumon, 5-HT, phthalanilide NSC 57155, various estrogens, progestogens and fatty acids, acetylsalicylic acid and similarly acting agents, hydroxylamine, glucose and KCN. The method may be useful for the screening of thrombogenic and antithrombotic properties of drugs.

A comparative study on adhesion and recovery of potential probiotic strains ofLactobacillusspp. by in vitro assay and analysis of human colon biopsies

2009 ◽  
Vol 21 (2) ◽  
Author(s):  
Nadja Larsen ◽  
Kim F. Michaelsen ◽  
Anders Pærregaard ◽  
Finn K. Vogensen ◽  
Mogens Jakobsen
Keyword(s):  
Comparative Study ◽  
Human Colon ◽  
In Vitro Assay ◽  
Vitro Assay ◽  
Probiotic Strains
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