Viability study of ice nucleating active bacteria (Pseudomonas Syringae) in freezing cloud droplets

2021 ◽  
Author(s):  
Alexei Kiselev ◽  
Corina Wieber ◽  
Ahmed Eid Zoheir Amer ◽  
Kersten Rabe
Keyword(s):  
Growth Rate ◽  
Pseudomonas Syringae ◽  
Survival Probability ◽  
High Speed ◽  
Pathogenic Bacteria ◽  
Outer Cell ◽  
High Concentration ◽  
Cloud Droplets ◽  
Viability Study ◽  
Active Bacteria

<p>The plant pathogenic bacteria<em> Pseudomonas syringae</em> are capable of inducing ice nucleation at low supercooling due to the presence of INA proteins on the outer cell membrane. Moreover, <em>P. Syringae</em> was shown to survive long-range transport in cold airmasses and redeposition to the earth’s surface with rain and snow. Thus, the life cycle of <em>P. syringae</em> is tightly coupled to the water cycle in the Earth's ecosystem. Understanding the survival mechanism of <em>P. Syringae</em> exposed to atmospheric cloud conditions is a prerequisite for characterization of bacteria as atmospheric ice nucleating particles, describing its dissemination paths and potential role in the spread of plant-pathogenic disease.</p><p>In this contribution we report on the viability study of ice nucleating active bacteria in freezing cloud droplets. To investigate the bacterial viability, water droplets containing several bacterial cells with low and high concentration of INA proteins are levitated in an electrodynamic balance (EDB) and cooled down to a temperature of -25°C. After freezing, the droplets are extracted from the EDB and the survival probability of the bacteria is determined by colony counting. A fluorescence stain and a high-speed video camera were used to visualize individual bacteria in the levitated droplets and to study their behavior during freezing.</p><p>The results have shown that the survival of bacteria depends on the freezing dynamics of bacteria-containing droplets (growth rate of ice in supercooled water). The <em>P. syringae</em> bacteria with high concentration of INA proteins are capable of inducing freezing at low supercooling and thus inhibit the growth rate of ice crystals, resulting in higher chance to survive the freezing. If high supercooling is achieved, the ice growth rate immediately after nucleation is very high and the survival probability is dramatically reduced.</p>

THE ACTIVITY OF ESSENTIAL OILS OBTAINED FROM SPECIES AND INTERSPECIES HYBRIDS OF THE Mentha GENUS AGAINST SELECTED PLANT PATHOGENIC BACTERIA

2018 ◽  
Vol 17 (6) ◽  
pp. 167-174 ◽  
Author(s):  
Małgorzata Schollenberger ◽  
Tomasz M. Staniek ◽  
Elżbieta Paduch-Cichal ◽  
Beata Dasiewicz ◽  
Agnieszka Gadomska-Gajadhur ◽  
...  
Keyword(s):  
Essential Oils ◽  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
Antimicrobial Effect ◽  
Mentha Piperita ◽  
Mentha Spicata ◽  
Plant Essential Oils ◽  
Plant Pathogenic Bacteria ◽  
Interspecies Hybrids

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv. syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. syringae.

Probiotics Slow the Growth of Pathogenic Bacteria

2019 ◽  
Vol 14 (1) ◽  
pp. 28-31 ◽  
Author(s):  
Rowles H. L.
Keyword(s):  
Growth Rate ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Diarrheal Disease ◽  
Growth Curves ◽  
Mortality Rates ◽  
Controlled Delivery ◽  
E Coli ◽  
Multiple Strains ◽  
Commercial Probiotics

Probiotics are live microorganisms, which when ingested in sufficient amounts, confer health benefits to the host by improving the gut microflora balance. The purpose of this research was to determine whether commercial probiotic products containing multitude of commensal bacteria would reduce the growth rate of pathogenic bacteria, specifically Escherichia coli and Salmonella typhimurium. Growth curves were established, and the growth rates were compared for samples of E. coli, S. typhimurium, Nature’s Bounty Controlled Delivery probiotic, Sundown Naturals Probiotic Balance probiotic, and cocultures of the pathogenic bacteria mixed with the probiotics. The findings of this research were that the commercial probiotics significantly reduced the growth rate of E. coli and S. typhimurium when combined in cocultures. Probiotics containing multiple strains may be taken prophylactically to reduce the risk of bacterial infections caused by E. coli and S. typhimurium. Probiotics could be used to reduce the high global morbidity and mortality rates of diarrheal disease.

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

scholarly journals In VitroActivity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

2014 ◽  
Vol 81 (1) ◽  
pp. 432-440 ◽  
Author(s):  
T. Sotelo ◽  
M. Lema ◽  
P. Soengas ◽  
M. E. Cartea ◽  
P. Velasco
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Degradation Products ◽  
Allyl Isothiocyanate ◽  
Leaf Extracts ◽  
Soil Pathogens ◽  
Content Type ◽  
Positive Effects

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.

scholarly journals Prediction and Activity of a Cationic α-Helix Antimicrobial Peptide ZM-804 from Maize

2021 ◽  
Vol 22 (5) ◽  
pp. 2643
Author(s):  
Mohamed F. Hassan ◽  
Abdelrahman M. Qutb ◽  
Wubei Dong
Keyword(s):  
Cdna Library ◽  
Pseudomonas Syringae ◽  
Inbred Line ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Confocal Laser ◽  
In Planta ◽  
Minimal Inhibitory Concentrations

Antimicrobial peptides (AMPs) are small molecules consisting of less than fifty residues of amino acids. Plant AMPs establish the first barrier of defense in the innate immune system in response to invading pathogens. The purpose of this study was to isolate new AMPs from the Zea mays L. inbred line B73 and investigate their antimicrobial activities and mechanisms against certain essential plant pathogenic bacteria. In silico, the Collection of Anti-Microbial Peptides (CAMPR3), a computational AMP prediction server, was used to screen a cDNA library for AMPs. A ZM-804 peptide, isolated from the Z. mays L. inbred line B73 cDNA library, was predicted as a new cationic AMP with high prediction values. ZM-804 was tested against eleven pathogens of Gram-negative and Gram-positive bacteria and exhibited high antimicrobial activities as determined by the minimal inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs). A confocal laser scanning microscope observation showed that the ZM-804 AMP targets bacterial cell membranes. SEM and TEM images revealed the disruption and damage of the cell membrane morphology of Clavibacter michiganensis subsp. michiganensis and Pseudomonas syringae pv. tomato (Pst) DC3000 caused by ZM-804. In planta, ZM-804 demonstrated antimicrobial activity and prevented the infection of tomato plants by Pst DC3000. Moreover, four virulent phytopathogenic bacteria were prevented from inducing hypersensitive response (HR) in tobacco leaves in response to low ZM-804 concentrations. ZM-804 exhibits low hemolytic activity against mouse red blood cells (RBCs) and is relatively safe for mammalian cells. In conclusion, the ZM-804 peptide has a strong antibacterial activity and provides an alternative tool for plant disease control. Additionally, the ZM-804 peptide is considered a promising candidate for human and animal drug development.

scholarly journals A Synergic Potential of Antimicrobial Peptides against Pseudomonas syringae pv. actinidiae

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1461
Author(s):  
Nuno Mariz-Ponte ◽  
Laura Regalado ◽  
Emil Gimranov ◽  
Natália Tassi ◽  
Luísa Moura ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Antimicrobial Peptides ◽  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
High Efficiency ◽  
Bacterial Canker ◽  
Membrane Permeation ◽  
Flow Cytometry Analysis ◽  
Pathogenic Agent ◽  
Peptide Mixtures

Pseudomonas syringae pv. actinidiae (Psa) is the pathogenic agent responsible for the bacterial canker of kiwifruit (BCK) leading to major losses in kiwifruit productions. No effective treatments and measures have yet been found to control this disease. Despite antimicrobial peptides (AMPs) having been successfully used for the control of several pathogenic bacteria, few studies have focused on the use of AMPs against Psa. In this study, the potential of six AMPs (BP100, RW-BP100, CA-M, 3.1, D4E1, and Dhvar-5) to control Psa was investigated. The minimal inhibitory and bactericidal concentrations (MIC and MBC) were determined and membrane damaging capacity was evaluated by flow cytometry analysis. Among the tested AMPs, the higher inhibitory and bactericidal capacity was observed for BP100 and CA-M with MIC of 3.4 and 3.4–6.2 µM, respectively and MBC 3.4–10 µM for both. Flow cytometry assays suggested a faster membrane permeation for peptide 3.1, in comparison with the other AMPs studied. Peptide mixtures were also tested, disclosing the high efficiency of BP100:3.1 at low concentration to reduce Psa viability. These results highlight the potential interest of AMP mixtures against Psa, and 3.1 as an antimicrobial molecule that can improve other treatments in synergic action.

scholarly journals BAK1 Is Not a Target of the Pseudomonas syringae Effector AvrPto

2011 ◽  
Vol 24 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Tingting Xiang ◽  
Na Zong ◽  
Jie Zhang ◽  
Jinfeng Chen ◽  
Mingsheng Chen ◽  
...  
Keyword(s):  
Cell Surface ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Plant Cell ◽  
Crucial Role ◽  
Pathogenic Bacteria ◽  
Effector Proteins ◽  
Receptor Like Kinase ◽  
Receptor Kinases ◽  
New Evidence

Plant cell surface-localized receptor kinases such as FLS2, EFR, and CERK1 play a crucial role in detecting invading pathogenic bacteria. Upon stimulation by bacterium-derived ligands, FLS2 and EFR interact with BAK1, a receptor-like kinase, to activate immune responses. A number of Pseudomonas syringae effector proteins are known to block immune responses mediated by these receptors. Previous reports suggested that both FLS2 and BAK1 could be targeted by the P. syringae effector AvrPto to inhibit plant defenses. Here, we provide new evidence further supporting that FLS2 but not BAK1 is targeted by AvrPto in plants. The AvrPto-FLS2 interaction prevented the phosphorylation of BIK1, a downstream component of the FLS2 pathway.

scholarly journals Discovery and Characterization of Low-Molecular Weight Inhibitors of Erwinia tracheiphila

2020 ◽  
Vol 110 (5) ◽  
pp. 989-998
Author(s):  
Cláudio M. Vrisman ◽  
Loïc Deblais ◽  
Yosra A. Helmy ◽  
Reed Johnson ◽  
Gireesh Rajashekara ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Throughput Screening ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Bacillus Species ◽  
Erwinia Tracheiphila ◽  
Static Activity ◽  
Low Toxicity

Plant pathogenic bacteria in the genus Erwinia cause economically important diseases, including bacterial wilt of cucurbits caused by Erwinia tracheiphila. Conventional bactericides are insufficient to control this disease. Using high-throughput screening, 464 small molecules (SMs) with either cidal or static activity at 100 µM against a cucumber strain of E. tracheiphila were identified. Among them, 20 SMs (SM1 to SM20), composed of nine distinct chemical moiety structures, were cidal to multiple E. tracheiphila strains at 100 µM. These lead SMs had low toxicity to human cells and honey bees at 100 µM. No phytotoxicity was observed on melon plants at 100 µM, except when SM12 was either mixed with Silwet L-77 and foliar sprayed or when delivered through the roots. Lead SMs did not inhibit the growth of beneficial Pseudomonas and Enterobacter species but inhibited the growth of Bacillus species. Nineteen SMs were cidal to Xanthomonas cucurbitae and showed >50% growth inhibition against Pseudomonas syringae pv. lachrymans. In addition, 19 SMs were cidal or static against Erwinia amylovora in vitro. Five SMs demonstrated potential to suppress E. tracheiphila when foliar sprayed on melon plants at 2× the minimum bactericidal concentration. Thirteen SMs reduced Et load in melon plants when delivered via roots. Temperature and light did not affect the activity of SMs. In vitro cidal activity was observed after 3 to 10 h of exposure to these five SMs. Here, we report 19 SMs that provide chemical scaffolds for future development of bactericides against plant pathogenic bacterial species.

scholarly journals Antibacterial Effect of Carvacrol and Coconut Oil on Selected Pathogenic Bacteria

2018 ◽  
Vol 49 (1) ◽  
pp. 46-52 ◽  
Author(s):  
M. Božik ◽  
P. Hovorková ◽  
P. Klouček
Keyword(s):  
Essential Oils ◽  
Lauric Acid ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Antibacterial Effect ◽  
Cocos Nucifera ◽  
Coconut Oil ◽  
High Concentration ◽  
Enterococcus Cecorum ◽  
Antibacterial Potential

AbstractEssential oils play a prominent role as flavouring agents and fragrances in the food and perfume industries. Carvacrol is a major component of various essential oils, such as oregano and thyme oils, and is responsible for their antimicrobial activity. Lauric acid is a medium-chain fatty acid (MCFA) with a high antibacterial potential. Both carvacrol and MCFAs have been used empirically as antimicrobial agents. Here, we tested the inhibitory properties of carvacrol and coconut (Cocos nuciferaL.) oil containing a high percentage of MCFAs against 5 harmful bacterial pathogens:Escherichia coli, SalmonellaEnteritidis,Staphylococcus aureus, Listeria monocytogenes, andEnterococcus cecorum. Gas chromatography (GC-FID) analysis of coconut oil showed a high concentration of lauric acid (41%). Microdilution antimicrobial assays showed that the combination of carvacrol and coconut oil had a stronger antibacterial effect against all tested bacteria than both agents separately. We conclude that carvacrol could significantly improve the antibacterial effect of coconut oil.

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