scholarly journals The PTS Components in Klebsiella pneumoniae Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance

2021 ◽  
Vol 9 (2) ◽  
pp. 335
Author(s):  
Novaria Sari Dewi Panjaitan ◽  
Yu-Tze Horng ◽  
Chih-Ching Chien ◽  
Hung-Chi Yang ◽  
Ren-In You ◽  
...  
Keyword(s):  
Survival Rate ◽  
Klebsiella Pneumoniae ◽  
Laser Scanning ◽  
Bacterial Resistance ◽  
Capsular Polysaccharide ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Bacteria ◽  
Wild Type ◽  
Macrophage Phagocytosis

Capsular polysaccharide (CPS) is a crucial virulence factor for Klebsiella pneumoniae infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of crr, encoding enzyme IIA of PTS, in K. pneumoniae enhanced the transcriptional activities of galF, wzi and gnd, which are in the cps gene cluster, leading to high CPS production. A crr mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The crr mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular crr mutant was higher than that of the wild-type. Deficiency of crr enhanced the transcriptional activities of etcABC which encodes another putative enzyme II complex of a PTS. Deletion of etcABC in the crr mutant reduced CPS production and the transcriptional activities of galF compared to those of the crr mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in K. pneumoniae. In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.

scholarly journals Apicomplexan co-infections impair with phagocytic activity in avian macrophages

2020 ◽  
Vol 119 (12) ◽  
pp. 4159-4168
Author(s):  
Runhui Zhang ◽  
Wanpeng Zheng ◽  
Arwid Daugschies ◽  
Berit Bangoura
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Three Dimensional Model ◽  
Host Interactions ◽  
Macrophage Phagocytosis ◽  
High Doses ◽  
Free Ranging

AbstractMixed infections of Toxoplasma gondii and Eimeria tenella are likely to occur frequently due to the high prevalence of both pathogens in free-ranging chickens. In this study, we investigated the co-occurrence of the two parasites in the same immune-competent host cell towards altered patterns of parasite-host interactions. Chicken blood monocyte–derived macrophages were co-infected with T. gondii RH tachyzoites and E. tenella Houghton sporozoites in vitro for 24 h. Through monitoring the uptake of pH-sensitive pHrodo™ Zymosan BioParticles (“Zymosan”) by macrophages, we created a three-dimensional model and to analyze quantitatively phagocytosis using confocal laser scanning microscopy. Assessments of parasite populations were performed by qPCR at 2, 6, 12, and 24 h post-infection (hpi). At 6 hpi, phagocytosis was inhibited in the E. tenella–infected cultures while no inhibition of phagocytosis was observed due to T. gondii. Phagocytosis activity revealed more complex interactions during co-infection. At 12 and 24 hpi, phagocytosis response to “Zymosan” was distinctly weaker in co-infected cells than in all other groups except for cells mono-infected with high doses of E. tenella at 24 hpi. By qPCR, significantly reduced numbers of both intracellular parasites were recorded (10-fold) in all infected groups at 2 hpi. At 12 hpi, the T. gondii population reached lowest values but dramatically increased by 24 hpi. Our data confirm that macrophage phagocytosis is involved in the control of invasion by apicomplexan parasites in chicken which particularly applies to E. tenella infection and it was able to be altered by the co-existing parasites.

scholarly journals Effect of arsenite on swimming motility delays surface colonization in Herminiimonas arsenicoxydans

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2336-2342 ◽  
Author(s):  
M. Marchal ◽  
R. Briandet ◽  
S. Koechler ◽  
B. Kammerer ◽  
P. N. Bertin
Keyword(s):  
Laser Scanning ◽  
Time Course ◽  
Wild Type Strain ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Arsenite Oxidase ◽  
Swimming Motility ◽  
In The Wild ◽  
Biofilm Development

Herminiimonas arsenicoxydans is a Gram-negative bacterium able to detoxify arsenic-contaminated environments by oxidizing arsenite [As(III)] to arsenate [As(V)] and by scavenging arsenic ions in an extracellular matrix. Its motility and colonization behaviour have been previously suggested to be influenced by arsenite. Using time-course confocal laser scanning microscopy, we investigated its biofilm development in the absence and presence of arsenite. Arsenite was shown to delay biofilm initiation in the wild-type strain; this was partly explained by its toxicity, which caused an increased growth lag time. However, this delayed adhesion step in the presence of arsenite was not observed in either a swimming motility defective fliL mutant or an arsenite oxidase defective aoxB mutant; both strains displayed the wild-type surface properties and growth capacities. We propose that during the biofilm formation process arsenite acts on swimming motility as a result of the arsenite oxidase activity, preventing the switch between planktonic and sessile lifestyles. Our study therefore highlights the existence, under arsenite exposure, of a competition between swimming motility, resulting from arsenite oxidation, and biofilm initiation.

scholarly journals The Expandables: Cracking the Staphylococcal Cell Wall for Expansion Microscopy

2021 ◽  
Vol 11 ◽  
Author(s):  
Tobias C. Kunz ◽  
Marcel Rühling ◽  
Adriana Moldovan ◽  
Kerstin Paprotka ◽  
Vera Kozjak-Pavlovic ◽  
...  
Keyword(s):  
Cell Wall ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Planktonic Bacteria ◽  
Simkania Negevensis

Expansion Microscopy (ExM) is a novel tool improving the resolution of fluorescence microscopy by linking the sample into a hydrogel that gets physically expanded in water. Previously, we have used ExM to visualize the intracellular Gram-negative pathogens Chlamydia trachomatis, Simkania negevensis, and Neisseria gonorrhoeae. Gram-positive bacteria have a rigid and thick cell wall that impedes classic expansion strategies. Here we developed an approach, which included a series of enzymatic treatments resulting in isotropic 4× expansion of the Gram-positive pathogen Staphylococcus aureus. We further demonstrate the suitability of the technique for imaging of planktonic bacteria as well as endocytosed, intracellular bacteria at a spatial resolution of approximately 60 nm with conventional confocal laser scanning microscopy.

scholarly journals High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 277
Author(s):  
Siddhi Desai ◽  
Kinjal Sanghrajka ◽  
Devarshi Gajjar
Keyword(s):  
Cell Death ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
High Adhesion ◽  
Biofilm Matrix

Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a “priority pathogen”. Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.

scholarly journals Cell-to-Cell Signaling in Xylella fastidiosa Suppresses Movement and Xylem Vessel Colonization in Grape

2008 ◽  
Vol 21 (10) ◽  
pp. 1309-1315 ◽  
Author(s):  
Subhadeep Chatterjee ◽  
Karyn L. Newman ◽  
Steven E. Lindow
Keyword(s):  
Cell Signaling ◽  
Type Strain ◽  
Laser Scanning ◽  
Wild Type Strain ◽  
Xylella Fastidiosa ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Deficient Mutant ◽  
Wild Type ◽  
Wide Range

Cell-to-cell signaling mediated by a fatty acid diffusible signaling factor (DSF) is central to the regulation of the virulence of Xylella fastidiosa. DSF production by X. fastidiosa is dependent on rpfF and, although required for insect colonization, appears to reduce its virulence to grape. To understand what aspects of colonization of grape are controlled by DSF in X. fastidiosa and, thus, those factors that contribute to virulence, we assessed the colonization of grape by a green fluorescent protein–marked rpfF-deficient mutant. The rpfF-deficient mutant was detected at a greater distance from the point of inoculation than the wild-type strain at a given sampling time, and also attained a population size that was up to 100-fold larger than that of the wild-type strain at a given distance from the point of inoculation. Confocal laser-scanning microscopy revealed that approximately 10-fold more vessels in petioles of symptomatic leaves harbored at least some cells of either the wild type or rpfF mutant when compared with asymptomatic leaves and, thus, that disease symptoms were associated with the extent of vessel colonization. Importantly, the rpfF mutant colonized approximately threefold more vessels than the wild-type strain. Although a wide range of colony sizes were observed in vessels colonized by both the wild type and rpfF mutant, the proportion of colonized vessels harboring large numbers of cells was significantly higher in plants inoculated with the rpfF mutant than with the wild-type strain. These studies indicated that the hypervirulence phenotype of the rpfF mutant is due to both a more extensive spread of the pathogen to xylem vessels and unrestrained multiplication within vessels leading to blockage. These results suggest that movement and multiplication of X. fastidiosa in plants are linked, perhaps because cell wall degradation products are a major source of nutrients. Thus, DSF-mediated cell-to-cell signaling, which restricts movement and colonization of X. fastidiosa, may be an adaptation to endophytic growth of the pathogen that prevents the excessive growth of cells in vessels.

scholarly journals Visualization of Proteus mirabilis within the Matrix of Urease-Induced Bladder Stones during Experimental Urinary Tract Infection

2002 ◽  
Vol 70 (1) ◽  
pp. 389-394 ◽  
Author(s):  
Xin Li ◽  
Hui Zhao ◽  
C. Virginia Lockatell ◽  
Cinthia B. Drachenberg ◽  
David E. Johnson ◽  
...  
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Proteus Mirabilis ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Alizarin Red ◽  
Negative Mutant

ABSTRACT The virulence of a urease-negative mutant of uropathogenic Proteus mirabilis and its wild-type parent strain was assessed by using a CBA mouse model of catheterized urinary tract infection. Overall, catheterized mice were significantly more susceptible than uncatheterized mice to infection by wild-type P. mirabilis. At a high inoculum, the urease-negative mutant successfully colonized bladders of catheterized mice but did not cause urolithiasis and was still severely attenuated in its ability to ascend to kidneys. Using confocal laser scanning microscopy and scanning electron microscopy, we demonstrated the presence of P. mirabilis within the urease-induced stone matrix. Alizarin red S staining was used to detect calcium-containing deposits in bladder and kidney tissues of P. mirabilis-infected mice.

scholarly journals In Situ Identification of Intracellular Bacteria Related to Paenibacillus spp. in the Mycelium of the Ectomycorrhizal Fungus Laccaria bicolor S238N

2003 ◽  
Vol 69 (7) ◽  
pp. 4243-4248 ◽  
Author(s):  
J. Bertaux ◽  
M. Schmid ◽  
N. Chemidlin Prevost-Boure ◽  
J. L. Churin ◽  
A. Hartmann ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Oligonucleotide Probe ◽  
Ectomycorrhizal Fungus ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Laccaria Bicolor ◽  
Intracellular Bacteria ◽  
The Past ◽  
Fermentor Culture

ABSTRACT Bacterial proliferations have recurrently been observed for the past 15 years in fermentor cultures of the ectomycorrhizal fungus Laccaria bicolor S238N, suggesting the presence of cryptic bacteria in the collection culture of this fungus. In this study, intracellular bacteria were detected by fluorescence in situ hybridization in combination with confocal laser scanning microscopy in several collection subcultures of L. bicolor S238N. They were small (0.5 μm in diameter), rare, and heterogeneously distributed in the mycelium and were identified as Paenibacillus spp. by using a 16S rRNA-directed oligonucleotide probe initially designed for bacteria isolated from a fermentor culture of L. bicolor S238N.

Colonization and bioherbicidal activity on green foxtail byPseudomonas fluorescensBRG100 in a pesta formulation

2012 ◽  
Vol 58 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Caressa J. Caldwell ◽  
Russell K. Hynes ◽  
Susan M. Boyetchko ◽  
Darren R. Korber
Keyword(s):  
Root Growth ◽  
Seed Coat ◽  
Laser Scanning ◽  
Doubling Time ◽  
Herbicidal Activity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Carbon Utilization ◽  
Green Foxtail

Pseudomonas fluorescens BRG100 produces secondary metabolites with herbicidal activity on green foxtail ( Setaria viridis ), an important weed pest in Canadian agriculture. Five gfp transformants of P. fluorescens BRG100 were compared with the wild-type isolate for green foxtail root herbicide activity, i.e., root growth suppression, doubling time, carbon utilization, and colonization of green foxtail root (proximal and distal regions). The most revealing comparison between the wild type and its gfp transformants was herbicidal activity on green foxtail. Herbicidal activity of transformant gfp-7 was not significantly different from the uninoculated control, suggesting that insertion of the gfp gene may have interfered with a gene, or genes, vital to the bioherbicide process. Doubling time, carbon utilization, and colonization of green foxtail did not differ to a great extent between the wild type and the gfp transformants, indicating their suitability as conservatively tagged organisms for subsequent colonization–herbicidal activity studies. Accordingly, a pesta granule formulation delivered transformant gfp-2 to the seed coat and roots of green foxtail. Epifluorescent and confocal laser scanning microscopy revealed the transformant gfp-2 colonized the ventral portion of the seed coat, root hairs, and all areas of the root except the root cap region, where gfp-2 presumably exerted herbicidal effects. These results suggest that P. fluorescens BRG100 has considerable potential as a bioherbicide because of its successful colonization and suppressive activity on green foxtail root growth.

Role of the luxS Gene in Initial Biofilm Formation by Streptococcus mutans

2015 ◽  
Vol 25 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Zhiyan He ◽  
Jingping Liang ◽  
Zisheng Tang ◽  
Rui Ma ◽  
Huasong Peng ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Mutant Strain ◽  
Biofilm Formation ◽  
Type Strain ◽  
Laser Scanning ◽  
Wild Type Strain ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Initial Biofilm

Quorum sensing (QS) is a process by which bacteria communicate with each other by secreting chemical signals called autoinducers (AIs). Among Gram-negative and Gram-positive bacteria, AI-2 synthesized by the LuxS enzyme is widespread. The aim of this study was to evaluate the effect of QS <i>luxS</i> gene on initial biofilm formation by <i>Streptococcus mutans</i>. The bacterial cell surface properties, including cell hydrophobicity (bacterial adherence to hydrocarbons) and aggregation, which are important for initial adherence during biofilm development, were investigated. The biofilm adhesion assay was evaluated by the MTT method. The structures of the 5-hour biofilms were observed by using confocal laser scanning microscopy, and QS-related gene expressions were investigated by real-time PCR. The <i>luxS</i> mutant strain exhibited higher biofilm adherence and aggregation, but lower hydrophobicity than the wild-type strain. The confocal laser scanning microscopy images revealed that the wild-type strain tended to form smaller aggregates with uniform distribution, whereas the <i>luxS</i> mutant strain aggregated into distinct clusters easily discernible in the generated biofilm. Most of the genes examined were downregulated in the biofilms formed by the <i>luxS</i> mutant strain, except the <i>gtfB </i>gene. QS <i>luxS</i> gene can affect the initial biofilm formation by <i>S. mutans.</i>

scholarly journals GR24, A Synthetic Strigolactone Analog, and Light Affect the Organization of Cortical Microtubules in Arabidopsis Hypocotyl Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuliya Krasylenko ◽  
George Komis ◽  
Sofiia Hlynska ◽  
Tereza Vavrdová ◽  
Miroslav Ovečka ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Genetic Manipulation ◽  
Cortical Microtubule ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Structured Illumination Microscopy ◽  
Continuous Darkness ◽  
Microtubule Organization

Strigolactones are plant hormones regulating cytoskeleton-mediated developmental events in roots, such as lateral root formation and elongation of root hairs and hypocotyls. The latter process was addressed herein by the exogenous application of a synthetic strigolactone, GR24, and an inhibitor of strigolactone biosynthesis, TIS108, on hypocotyls of wild-type Arabidopsis and a strigolactone signaling mutant max2-1 (more axillary growth 2-1). Owing to the interdependence between light and strigolactone signaling, the present work was extended to seedlings grown under a standard light/dark regime, or under continuous darkness. Given the essential role of the cortical microtubules in cell elongation, their organization and dynamics were characterized under the conditions of altered strigolactone signaling using fluorescence microscopy methods with different spatiotemporal capacities, such as confocal laser scanning microscopy (CLSM) and structured illumination microscopy (SIM). It was found that GR24-dependent inhibition of hypocotyl elongation correlated with changes in cortical microtubule organization and dynamics, observed in living wild-type and max2-1 seedlings stably expressing genetically encoded fluorescent molecular markers for microtubules. Quantitative assessment of microscopic datasets revealed that chemical and/or genetic manipulation of strigolactone signaling affected microtubule remodeling, especially under light conditions. The application of GR24 in dark conditions partially alleviated cytoskeletal rearrangement, suggesting a new mechanistic connection between cytoskeletal behavior and the light-dependence of strigolactone signaling.

Sign in / Sign up

Export Citation Format

Share Document