scholarly journals A Metzincin and TIMP-Like Protein Pair of a Phage Origin Sensitize Listeria monocytogenes to Phage Lysins and Other Cell Wall Targeting Agents

2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Mammalian Cells ◽  
Protein Pair ◽  
Growth Conditions ◽  
Wall Structure ◽  
Antibiotic Resistant ◽  
Extracellular Milieu ◽  
Virion Release ◽  
Genes Encoding

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.

scholarly journals The Transcription Factor Con7-1 Is a Master Regulator of Morphogenesis and Virulence in Fusarium oxysporum

2015 ◽  
Vol 28 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Carmen Ruiz-Roldán ◽  
Yolanda Pareja-Jaime ◽  
José Antonio González-Reyes ◽  
M. Isabel G. Roncero
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Gene Expression Analysis ◽  
Wall Structure ◽  
Targeted Deletion ◽  
Signal Perception ◽  
Cell Wall Biogenesis ◽  
Primary And Secondary Metabolism ◽  
Genes Encoding

Previous studies have demonstrated the essential role of morphogenetic regulation in Fusarium oxysporum pathogenesis, including processes such as cell-wall biogenesis, cell division, and differentiation of infection-like structures. We identified three F. oxysporum genes encoding predicted transcription factors showing significant identities to Magnaporthe oryzae Con7p, Con7-1, plus two identical copies of Con7-2. Targeted deletion of con7-1 produced nonpathogenic mutants with altered morphogenesis, including defects in cell wall structure, polar growth, hyphal branching, and conidiation. By contrast, simultaneous inactivation of both con7-2 copies caused no detectable defects in the resulting mutants. Comparative microarray-based gene expression analysis indicated that Con7-1 modulates the expression of a large number of genes involved in different biological functions, including host–pathogen interactions, morphogenesis and development, signal perception and transduction, transcriptional regulation, and primary and secondary metabolism. Taken together, our results point to Con7-1 as general regulator of morphogenesis and virulence in F. oxysporum.

scholarly journals EslB is required for cell wall biosynthesis and modification in Listeria monocytogenes

2020 ◽  
Author(s):  
Jeanine Rismondo ◽  
Lisa M. Schulz ◽  
Maria Yacoub ◽  
Ashima Wadhawan ◽  
Michael Hoppert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Listeria Monocytogenes ◽  
Abc Transporter ◽  
Cell Lysis ◽  
Growth Conditions ◽  
Cell Wall Integrity ◽  
Growth Defect ◽  
Cell Wall Biosynthesis ◽  
High Concentrations

Lysozyme is an important component of the innate immune system. It functions by hydrolysing the peptidoglycan (PG) layer of bacteria. The human pathogen Listeria monocytogenes is intrinsically lysozyme resistant. The peptidoglycan N-deacetylase PgdA and O-acetyltransferase OatA are two known factors contributing to its lysozyme resistance. Furthermore, it was shown that the absence of components of an ABC transporter, here referred to as EslABC, leads to reduced lysozyme resistance. How its activity is linked to lysozyme resistance is still unknown. To investigate this further, a strain with a deletion in eslB, coding for a membrane component of the ABC transporter, was constructed in L. monocytogenes strain 10403S. The eslB mutant showed a 40-fold reduction in the minimal inhibitory concentration to lysozyme. Analysis of the PG structure revealed that the eslB mutant produced PG with reduced levels of O-acetylation. Using growth and autolysis assays, we show that the absence of EslB manifests in a growth defect in media containing high concentrations of sugars and increased endogenous cell lysis. A thinner PG layer produced by the eslB mutant under these growth conditions might explain these phenotypes. Furthermore, the eslB mutant had a noticeable cell division defect and formed elongated cells. Microscopy analysis revealed that an early cell division protein still localized in the eslB mutant indicating that a downstream process is perturbed. Based on our results, we hypothesize that EslB affects the biosynthesis and modification of the cell wall in L. monocytogenes and is thus important for the maintenance of cell wall integrity. IMPORTANCE The ABC transporter EslABC is associated with the intrinsic lysozyme resistance of Listeria monocytogenes. However, the exact role of the transporter in this process and in the physiology of L. monocytogenes is unknown. Using different assays to characterize an eslB deletion strain, we found that the absence of EslB not only affects lysozyme resistance, but also endogenous cell lysis, cell wall biosynthesis, cell division and the ability of the bacterium to grow in media containing high concentrations of sugars. Our results indicate that EslB is by a yet unknown mechanism an important determinant for cell wall integrity in L. monocytogenes.

scholarly journals A family of glycosylphosphatidylinositol-linked aspartyl proteases is required for virulence of Candida glabrata

2007 ◽  
Vol 104 (18) ◽  
pp. 7628-7633 ◽  
Author(s):  
Rupinder Kaur ◽  
Biao Ma ◽  
Brendan P. Cormack
Keyword(s):  
Cell Wall ◽  
Mammalian Cells ◽  
Candida Glabrata ◽  
Global Changes ◽  
Cell Wall Proteins ◽  
Culture Model ◽  
Genes Encoding ◽  
Tissue Culture Model ◽  
A Cell ◽  
Aspartyl Proteases

Candida glabrata is a yeast pathogen of humans. We have established a tissue culture model to analyze the interaction of C. glabrata with macrophages. Transcript profiling of yeast ingested by macrophages reveals global changes in metabolism as well as increased expression of a gene family (YPS genes) encoding extracellular glycosylphosphatidylinositol-linked aspartyl proteases. Eight of these YPS genes are found in a cluster that is unique to C. glabrata. Genetic analysis shows that the C. glabrata YPS genes are required for cell wall integrity, adherence to mammalian cells, survival in macrophages and virulence. By monitoring the processing of a cell wall adhesin, Epa1, we also show that Yps proteases play an important role in cell wall re-modeling by removal and release of glycosylphosphatidylinositol-anchored cell wall proteins.

scholarly journals Conserved Serine/Threonine Kinase Encoded by CBK1 Regulates Expression of Several Hypha-Associated Transcripts and Genes Encoding Cell Wall Proteins in Candida albicans

2002 ◽  
Vol 184 (7) ◽  
pp. 2058-2061 ◽  
Author(s):  
Mark D. McNemar ◽  
William A. Fonzi
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Morphological Differentiation ◽  
Growth Conditions ◽  
Cell Wall Proteins ◽  
Serine Threonine Kinase ◽  
General Role ◽  
Threonine Kinase ◽  
Genes Encoding ◽  
Opportunistic Fungal Pathogen

ABSTRACT The opportunistic fungal pathogen, Candida albicans, is reported to have several potential virulence factors. A potentially significant factor is the ability to undergo morphological transition from yeast to hypha. This alteration of form is accompanied by many changes within the cell, including alterations in gene expression and cell wall composition. We have isolated a gene that encodes a highly conserved serine/threonine kinase that appears to be involved in the regulation of proteins associated with the cell wall. We have assigned the designation CBK1 (cell wall biosynthesis kinase 1) to this gene. Mutants lacking CBK1 form large aggregates of round cells under all growth conditions and lack the ability to undergo morphological differentiation. Additionally, these mutants show an altered pattern of expression of several transcripts encoding proteins associated with the cell wall. The results suggest that the kinase encoded by CBK1 plays a general role in the maintenance and alteration of the cell wall of C. albicans in all morphologies.

Phloem fibres as motors of gravitropic behaviour of flax plants: level of transcriptome

2018 ◽  
Vol 45 (2) ◽  
pp. 203 ◽  
Author(s):  
Oleg Gorshkov ◽  
Natalia Mokshina ◽  
Nadezda Ibragimova ◽  
Marina Ageeva ◽  
Natalia Gogoleva ◽  
...  
Keyword(s):  
Cell Wall ◽  
Large Scale ◽  
Turgor Pressure ◽  
Control Plant ◽  
Transcriptome Profiling ◽  
Transcript Abundance ◽  
Regulatory Elements ◽  
Wall Structure ◽  
Vertical Position ◽  
Genes Encoding

Restoration of stem vertical position after plant inclination is a widely spread version of plant orientation in accordance with gravity vector direction. Gravitropic behaviour of flax plants involves the formation of curvature in stem region that has ceased elongation long in advance of stem inclination. The important participants of such behaviour are phloem fibres with constitutively formed tertiary cell wall (G-layer). We performed the large-scale transcriptome profiling of phloem fibres isolated from pulling and opposite sides of gravitropic curvature and compared with control plant fibres. Significant changes in transcript abundance take place for genes encoding proteins of several ion channels, transcription factors and other regulating elements. The largest number of upregulated genes belonged to the cell wall category; many of those were specifically upregulated in fibres of pulling stem side. The obtained data permit to suggest the mechanism of fibre participation in gravitropic reaction that involves the increase of turgor pressure and the rearrangements of cell wall structure in order to improve contractile properties, and to identify the regulatory elements that operate specifically in the fibres of the pulling stem side making gelatinous phloem fibres an important element of gravitropic response in herbaceous plants.

scholarly journals Revisiting the expression signature of pks15/1 unveils regulatory patterns controlling phenolphtiocerol and phenolglycolipid production in pathogenic mycobacteria

2020 ◽  
Author(s):  
Beatriz Ramos ◽  
Stephen V. Gordon ◽  
Mónica V. Cunha
Keyword(s):  
Cell Wall ◽  
Iron Concentration ◽  
Growth Conditions ◽  
Type I ◽  
Transcriptome Data ◽  
Dynamic Heterogeneity ◽  
Mycolic Acids ◽  
Transcriptional Signature ◽  
Genes Encoding ◽  
Highly Correlated

AbstractOne of the most relevant and exclusive characteristics of mycobacteria is its cell wall, composed by mycolic acids. Amid these are two related families of glycosylated lipids, diphthioceranates and phthiocerol dimycocerosate (PDIM) and its variant phenolic glycolipids (PGL). PGL have been associated with cell wall impermeability, phagocytosis, defence against nitrosative and oxidative stress and, supposedly, biofilm formation. In bacteria from the Mycobacterium tuberculosis complex, the biosynthetic pathway of the phenolphthiocerol moiety of PGL depends upon the expression of several genes encoding type I polyketide synthases (PKS), namely ppsA-E and pks15/1 constituting the PDIM + PGL locus, highly conserved in PDIM/PGL-producing strains. Consensus has not been achieved regarding the genetic organization of pks15/1 locus and little effort has been put on the disclosure of its transcriptional signature. Here we explore publicly available datasets of transcriptome data (RNA-seq) from more than 100 experiments in 40 growth conditions to outline the transcriptional structure and signature of pks15/1 and use a differential expression approach to infer the regulatory patterns involving these and related genes. We show that pks1 is highly correlated with fadD22, Rv2949c, lppX, fadD29 and, also, pks6 and pks12, with the first three putatively integrating a polycistronic structure. We evidence dynamic heterogeneity of transcription within the genes involved in phenolphtiocerol and phenolglycolipid production, most exhibiting up-regulation upon acidic pH and antibiotic exposure and down-regulation under hypoxia, dormancy, and low/high iron concentration. We finally propose a model based on transcriptome data in which σD positively regulates pks1, pks15 and fadD22, while σB and σE factors exert negative regulation at an upper level.

scholarly journals EslB is required for cell wall biosynthesis and modification in Listeria monocytogenes

2020 ◽  
Author(s):  
Jeanine Rismondo ◽  
Lisa M. Schulz ◽  
Maria Yacoub ◽  
Ashima Wadhawan ◽  
Michael Hoppert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Listeria Monocytogenes ◽  
Abc Transporter ◽  
Cell Lysis ◽  
Growth Conditions ◽  
Cell Wall Integrity ◽  
Growth Defect ◽  
Cell Wall Biosynthesis ◽  
High Concentrations

ABSTRACTLysozyme is an important component of the innate immune system. It functions by hydrolysing the peptidoglycan (PG) layer of bacteria. The human pathogen Listeria monocytogenes is intrinsically lysozyme resistant. The peptidoglycan N-deacetylase PgdA and O-acetyltransferase OatA are two known factors contributing to its lysozyme resistance. Furthermore, it was shown that the absence of components of an ABC transporter, here referred to as EslABC, leads to reduced lysozyme resistance. How its activity is linked to lysozyme resistance is still unknown. To investigate this further, a strain with a deletion in eslB, coding for a membrane component of the ABC transporter, was constructed in L. monocytogenes strain 10403S. The eslB mutant showed a 40-fold reduction in the minimal inhibitory concentration to lysozyme. Analysis of the PG structure revealed that the eslB mutant produced PG with reduced levels of O-acetylation. Using growth and autolysis assays, we show that the absence of EslB manifests in a growth defect in media containing high concentrations of sugars and increased endogenous cell lysis. A thinner PG layer produced by the eslB mutant under these growth conditions might explain these phenotypes. Furthermore, the eslB mutant had a noticeable cell division defect and formed elongated cells. Microscopy analysis revealed that an early cell division protein still localized in the eslB mutant indicating that a downstream process is perturbed. Based on our results, we hypothesize that EslB affects the biosynthesis and modification of the cell wall in L. monocytogenes and is thus important for the maintenance of cell wall integrity.IMPORTANCEThe ABC transporter EslABC is associated with the intrinsic lysozyme resistance of Listeria monocytogenes. However, the exact role of the transporter in this process and in the physiology of L. monocytogenes is unknown. Using different assays to characterize an eslB deletion strain, we found that the absence of EslB not only affects lysozyme resistance, but also endogenous cell lysis, cell wall biosynthesis, cell division and the ability of the bacterium to grow in media containing high concentrations of sugars. Our results indicate that EslB is by a yet unknown mechanism an important determinant for cell wall integrity in L. monocytogenes.

scholarly journals Optical Tweezers Cause Physiological Damage to Escherichia coli and Listeria Bacteria

2008 ◽  
Vol 74 (8) ◽  
pp. 2441-2446 ◽  
Author(s):  
M. B. Rasmussen ◽  
L. B. Oddershede ◽  
H. Siegumfeldt
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Optical Tweezers ◽  
Laser Power ◽  
Fluorescent Protein ◽  
Growth Conditions ◽  
Ph Gradient ◽  
Bacterial Cells ◽  
E Coli

ABSTRACT We investigated the degree of physiological damage to bacterial cells caused by optical trapping using a 1,064-nm laser. The physiological condition of the cells was determined by their ability to maintain a pH gradient across the cell wall; healthy cells are able to maintain a pH gradient over the cell wall, whereas compromised cells are less efficient, thus giving rise to a diminished pH gradient. The pH gradient was measured by fluorescence ratio imaging microscopy by incorporating a pH-sensitive fluorescent probe, green fluorescent protein or 5(6)-carboxyfluorescein diacetate succinimidyl ester, inside the bacterial cells. We used the gram-negative species Escherichia coli and three gram-positive species, Listeria monocytogenes, Listeria innocua, and Bacillus subtilis. All cells exhibited some degree of physiological damage, but optically trapped E. coli and L. innocua cells and a subpopulation of L. monocytogenes cells, all grown with shaking, showed only a small decrease in pH gradient across the cell wall when trapped by 6 mW of laser power for 60 min. However, another subpopulation of Listeria monocytogenes cells exhibited signs of physiological damage even while trapped at 6 mW, as did B. subtilis cells. Increasing the laser power to 18 mW caused the pH gradient of both Listeria and E. coli cells to decrease within minutes. Moreover, both species of Listeria exhibited more-pronounced physiological damage when grown without shaking than was seen in cells grown with shaking, and the degree of damage is therefore also dependent on the growth conditions.

scholarly journals EAP1, a Candida albicans Gene Involved in Binding Human Epithelial Cells

2003 ◽  
Vol 2 (6) ◽  
pp. 1266-1273 ◽  
Author(s):  
Fang Li ◽  
Sean P. Palecek
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Epithelial Cells ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Genomic Library ◽  
Flow Chamber ◽  
Genes Encoding ◽  
Dependent Protein ◽  
Yeast Genes

ABSTRACT Candida albicans adhesion to host tissues contributes to its virulence and adhesion to medical devices permits biofilm formation, but we know relatively little about the molecular mechanisms governing C. albicans adhesion to materials or mammalian cells. Saccharomyces cerevisiae provides an attractive model system for studying adhesion in yeast because of its well-characterized genetics and gene expression systems and the conservation of signal transduction pathways among the yeasts. In this study, we used a parallel plate flow chamber to screen and characterize attachment of a flo8Δ S. cerevisiae strain expressing a C. albicans genomic library to a polystyrene surface. The gene EAP1 was isolated as a putative cell wall adhesin. Sequence analysis of EAP1 shows that it contains a signal peptide, a glycosylphosphatidylinositol anchor site, and possesses homology to many other yeast genes encoding cell wall proteins. In addition to increasing adhesion to polystyrene, heterologous expression of EAP1 in S. cerevisiae and autonomous expression of EAP1 in a C. albicans efg1 homozygous null mutant significantly enhanced attachment to HEK293 kidney epithelial cells. EAP1 expression also restored invasive growth to haploid flo8Δ and flo11Δ strains as well as filamentous growth to diploid flo8/flo8 and flo11/flo11 strains. Transcription of EAP1 in C. albicans is regulated by the transcription factor Efg1p, suggesting that EAP1 expression is activated by the cyclic AMP-dependent protein kinase pathway.

scholarly journals The zinc cluster transcription factor Rha1 is a positive filamentation regulator in Candida albicans

2020 ◽  
Author(s):  
Raha Parvizi Omran ◽  
Chris Law ◽  
Vanessa Dumeaux ◽  
Joachim Morschhäuser ◽  
Malcolm Whiteway
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transcription Factors ◽  
Transcriptional Profiling ◽  
Hyphal Growth ◽  
Growth Conditions ◽  
Hyphal Development ◽  
Zinc Cluster ◽  
Genes Encoding

AbstractZinc cluster transcription factors are essential fungal specific regulators of gene expression. In the dimorphic pathogen Candida albicans, they control processes ranging from metabolism and stress adaptation to mating, virulence, and antifungal resistance. Here, we have identified the gene CaORF19.1604 as encoding a zinc cluster transcription factor that acts as a regulator of filament development. Hyperactivation of CaORF19.1604, which we have named RHA1 for Regulator of Hyphal Activity, leads to a wrinkled colony morphology under non-hyphal growth conditions, to pseudohyphal growth and filament formation, to invasiveness and enhanced biofilm formation.  Cells with activated Rha1 are sensitive to cell wall modifying agents such as Congo red and the echinocandin drug caspofungin but show normal sensitivity to fluconazole. RNA-sequencing-based transcriptional profiling of the activated Rha1 strain reveals the up-regulation of genes for core filamentation and cell-wall-adhesion-related proteins such as Als1, Als3, Ece1, and Hwp1. Upregulation is also seen for the genes for the hyphal-inducing transcription factors Brg1 and Ume6 and genes encoding several enzymes involved in arginine metabolism, while downregulation is seen for the hyphal repressor Nrg1. The deletion of BRG1 blocks the filamentation caused by activated Rha1, while null mutants of UME6 result in a partial block. Deletion of RHA1 can partially reduce healthy hyphal development triggered by environmental conditions such as Spider medium or serum at 37°C.In contrast to the limited effect of either single mutant, the double rha1 ume6 deletion strain is totally defective in both serum and Spider medium stimulated hyphal development. While the loss of Brg1 function blocks serum-stimulated hyphal development, this block can be significantly bypassed by Rha1 hyperactivity, and the combination of Rha1 hyperactivity and serum addition can generate significant polarization in even brg1 ume6 double mutants. Our results thus suggest that in response to external signals, Rha1 functions to facilitate the switch from an Nrg1 controlled yeast state to a Brg1/Ume6 regulated hyphal state.Author SummaryCandida albicans is the predominant human fungal pathogen, generating a mortality rate of 40% in systemically infected patients. The ability of Candida albicans to change its morphology is a determinant of its tissue penetration and invasion in response to variant host-related stimuli. The regulatory mechanism for filamentation includes a complex network of transcription factors that play roles in regulating hyphae associated genes. We identify here a new regulator of filamentation from the zinc cluster transcription factor family. We present evidence suggesting that this transcription factor assists the Nrg1/Brg1 switch regulating hyphal development.

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