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1.
Proc Natl Acad Sci U S A ; 121(41): e2412541121, 2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39352926

RESUMO

Flagella are highly complex rotary molecular machines that enable bacteria to not only migrate to optimal environments but also to promote range expansion, competitiveness, virulence, and antibiotic survival. Flagellar motility is an energy-demanding process, where the sum of its production (biosynthesis) and operation (rotation) costs has been estimated to total ~10% of the entire energy budget of an Escherichia coli cell. The acquisition of such a costly adaptation process is expected to secure short-term benefits by increasing competitiveness and survival, as well as long-term evolutionary fitness gains. While the role of flagellar motility in bacterial survival has been widely reported, its direct influence on the rate of evolution remains unclear. We show here that both production and operation costs contribute to elevated mutation rates. Our findings suggest that flagellar movement may be an important player in tuning the rate of bacterial evolution.


Assuntos
Escherichia coli , Flagelos , Flagelos/metabolismo , Flagelos/fisiologia , Flagelos/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Mutação , Taxa de Mutação , Movimento , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Evolução Biológica
2.
Braz J Microbiol ; 55(3): 2727-2738, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39222218

RESUMO

Due to the increasing occurrence of drug resistant urinary tract infections (UTI) among children, there is a need to investigate alternative effective treatment protocols such as nanoparticles. Flagella and fimbriae are primary factors contributing the virulence of urinary tract infecting bacteria. The aim of this study was to assess the antibacterial effects of zinc oxide nanoparticles which have been synthesized using both chemical and green methods on multi-drug resistant (MDR) uropathogenic bacteria encoding fli and fim genes and investigating their binding ability to bacterial appendage proteins. A total of 30 urine culture samples were collected from children under 2 years old diagnosed with urinary tract infection. The isolates underwent antibiotic suseptibility assessment and the isolates demonstrating MDR were subjected to molecular amplification of fimG (fimbrial) and fliD and fliT (flagellal) genes. The confirmation of cellular appendages was achieved through silver nitrate staining. The antibacterial efficacy of the synthetized nanoparticles was assessed using the micro and macrodilution methods. The successful binding of nanoparticles to bacterial appendage proteins was confirmed through mobility shift and membrane filter assays. The dimensions of chemically synthesized ZnO nanoparticles and green nanoparticles were measured at 30 nm and 85 nm, respectively, with the exhibition of hexagonal geometries. The nanoparticles synthesized through chemical and green methods exhibited minimum inhibitory concentrations (MIC) of 0.0062-0.025 g/L and 0.3 g/L, respectively. The ability of ZnO nanoparticles to bind bacterial appendage proteins and to combat MDR uropathogenic bacteria are promising for new treatment protocols against UTI in children in future.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana Múltipla , Flagelos , Infecções Urinárias , Óxido de Zinco , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Óxido de Zinco/metabolismo , Antibacterianos/farmacologia , Humanos , Infecções Urinárias/microbiologia , Infecções Urinárias/tratamento farmacológico , Flagelos/efeitos dos fármacos , Flagelos/genética , Flagelos/metabolismo , Testes de Sensibilidade Microbiana , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Fímbrias Bacterianas/efeitos dos fármacos , Nanopartículas/química , Lactente , Nanopartículas Metálicas/química
3.
Sci Adv ; 10(38): eadp5636, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39303042

RESUMO

Adaptation of the response to stimuli is a fundamental process for all organisms. Here, we show that the adaptation enzyme CheB methylesterase of Escherichia coli assembles to the ON state receptor array after exposure to the repellent l-isoleucine and dissociates from the array after adaptation is complete. The duration of increased CheB localization and the time of highly clockwise-biased flagellar rotation were similar and depended on the strength of the stimulus. The increase in CheB at the receptor array and the decrease in cytoplasmic CheB were both ~100 molecules, which represents 15 to 20% of the total cellular content of CheB. We confirmed that the main binding site for CheB in the ON state array is the P2 domain of phosphorylated CheA, with a second minor site being the carboxyl-terminal pentapeptide of the serine chemoreceptor. Thus, we have been able to quantify the regulation of the signal output of the receptor array by the intracellular dynamics of an adaptation enzyme.


Assuntos
Adaptação Fisiológica , Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas Quimiotáticas Aceptoras de Metil/metabolismo , Proteínas Quimiotáticas Aceptoras de Metil/genética , Sítios de Ligação , Fosforilação , Flagelos/metabolismo , Ligação Proteica , Proteínas de Bactérias/metabolismo , Quimiotaxia
4.
Microbiol Spectr ; 12(10): e0132524, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39248473

RESUMO

Loss of the flagellum marks the pathoadaptation of Pseudomonas aeruginosa to the cystic fibrosis (CF) airway environment during lung disease. Losing the flagellum is advantageous to the bacterium as the flagellum can be recognized by immune cells. The primary purpose of the flagellum is, however, to provide motility to the bacterium. Our goal was to determine whether the loss of flagellar motility or the loss of flagellum expression contributes to P. aeruginosa lung infection in CF. To address this, wild-type and gut-corrected FABP-human cystic fibrosis transmembrane conductance regulator (hCFTR) mice deficient in the murine Cftr gene were infected intratracheally with lethal doses of wild-type or flagellum-deficient P. aeruginosa. While there was no significant difference in the survival of wild-type mice after infection with either of the bacterial strains, a significantly higher mortality was observed in FABP-hCFTR mice infected with flagellum-deficient P. aeruginosa, compared to mice infected with their flagellated counterparts. When FABP-hCFTR mice were infected with isogenic, motility-deficient flagellated mutants, animal survival and lung bacterial titers were similar to those observed in mice infected with the wild-type bacterium. Airway levels of neutrophils and the amount neutrophil elastase were similar in mice infected with either the wild-type bacteria or the flagellum-deficient P. aeruginosa. Our results show that FABP-hCFTR mice have a different response to flagellum loss in P. aeruginosa compared to wild-type animals. The loss of flagellum expression, rather than the loss of motility, is the main driver behind the increased virulence of flagellum-deficient P. aeruginosa in CF. These observations provide new insight into P. aeruginosa virulence in CF.IMPORTANCEPseudomonas aeruginosa, a major respiratory pathogen in cystic fibrosis, is known to lose its flagellum during the course of infection in the airways. Here, we show that the loss of flagellum leads to a more enhanced virulence in Cftr-deficient cystic fibrosis mice than in control animals. Loss of flagellum expression, rather than the loss of flagellar swimming motility, represents the main driver behind this increased virulence suggesting that this appendage plays a specific role in P. aeruginosa virulence in cystic fibrosis airways.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística , Fibrose Cística , Modelos Animais de Doenças , Flagelos , Infecções por Pseudomonas , Pseudomonas aeruginosa , Animais , Fibrose Cística/microbiologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Camundongos , Infecções por Pseudomonas/microbiologia , Flagelos/genética , Virulência , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/deficiência , Humanos , Pulmão/microbiologia , Pulmão/patologia , Mutação , Feminino
5.
Zool Res ; 45(5): 1061-1072, 2024 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-39245650

RESUMO

The structural integrity of the sperm flagellum is essential for proper sperm function. Flagellar defects can result in male infertility, yet the precise mechanisms underlying this relationship are not fully understood. CCDC181, a coiled-coil domain-containing protein, is known to localize on sperm flagella and at the basal regions of motile cilia. Despite this knowledge, the specific functions of CCDC181 in flagellum biogenesis remain unclear. In this study, Ccdc181 knockout mice were generated. The absence of CCDC181 led to defective sperm head shaping and flagellum formation. Furthermore, the Ccdc181 knockout mice exhibited extremely low sperm counts, grossly aberrant sperm morphologies, markedly diminished sperm motility, and typical multiple morphological abnormalities of the flagella (MMAF). Additionally, an interaction between CCDC181 and the MMAF-related protein LRRC46 was identified, with CCDC181 regulating the localization of LRRC46 within sperm flagella. These findings suggest that CCDC181 plays a crucial role in both manchette formation and sperm flagellum biogenesis.


Assuntos
Camundongos Knockout , Proteínas dos Microtúbulos , Cauda do Espermatozoide , Animais , Masculino , Camundongos , Fertilidade/fisiologia , Flagelos/metabolismo , Flagelos/fisiologia , Motilidade dos Espermatozoides , Cauda do Espermatozoide/metabolismo , Cauda do Espermatozoide/fisiologia , Espermatozoides/fisiologia , Proteínas dos Microtúbulos/genética , Proteínas dos Microtúbulos/metabolismo
6.
Eur Phys J E Soft Matter ; 47(9): 56, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-39278991

RESUMO

Flagellar swimming hydrodynamics confers a recognized advantage for attachment on solid surfaces. Whether this motility further enables the following environmental cues was experimentally explored. Motile E. coli (OD ~ 0.1) in a 100 µm-thick channel were exposed to off-equilibrium gradients set by a chemorepellent Ni(NO3)2-source (250 mM). Single bacterial dynamics at the solid surface was analyzed by dark-field videomicroscopy at a fixed position. The number of bacteria indicated their congregation into a wave escaping from the repellent source. Besides the high velocity drift in the propagation direction within the wave, an unexpectedly high perpendicular component drift was also observed. Swimming hydrodynamics CW-bends the bacteria trajectories during their primo approach to the surface (< 2 µm), and a high enough tumbling frequency likely preserves a notable lateral drift. This comprehension substantiates a survival strategy tailored to toxic environments, which involves drifting along surfaces, promoting the inception of colonization at the most advantageous sites.


Assuntos
Escherichia coli , Hidrodinâmica , Escherichia coli/fisiologia , Propriedades de Superfície , Flagelos/fisiologia , Flagelos/metabolismo , Movimento , Níquel/química , Nitratos/metabolismo , Nitratos/química
7.
Microbiome ; 12(1): 175, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39289694

RESUMO

BACKGROUND: Lactobacillus acidophilus is a commensal urinary bacterium found more abundantly in healthy individuals than in stone patients. Hence, it has been proposed to play an inhibitory role in kidney stone disease (KSD) but with unclear mechanisms. We therefore investigated the direct effects of L. acidophilus on calcium oxalate (CaOx) stone development compared with Escherichia coli, which is known to promote CaOx stone formation. RESULTS: L. acidophilus at 1 × 103 CFU/ml  significantly reduced the abundance of newly formed crystals, enlargement and aggregation of seeded crystals, and crystal adhesion on renal cell membranes. By contrast, E. coli at 1 × 103 CFU/ml significantly enhanced crystal growth and aggregation but did not affect crystallization and crystal-cell adhesion. Oxalate consumption assay showed that neither L. acidophilus nor E. coli significantly reduced the remaining oxalate level after 1 - 3 h incubation. However, both of them adhered to CaOx crystals. Surface component detection revealed that only L. acidophilus expressed S-layer protein, whereas only E. coli exhibited flagella on their surfaces. Removal of L. acidophilus S-layer protein and E. coli flagella completely abolished the inhibitory and promoting effects of L. acidophilus and E. coli, respectively. CONCLUSIONS: L. acidophilus inhibits CaOx stone development by hampering crystallization, growth, aggregation and cell-adhesive ability of CaOx. By contrast, E. coli enhances CaOx stone development by promoting CaOx growth and aggregation. Their contradictory effects are most likely from differential surface components (i.e., S-layer protein on L. acidophilus and flagella on E. coli) not from oxalate-degrading ability. Video Abstract.


Assuntos
Aderência Bacteriana , Oxalato de Cálcio , Escherichia coli , Cálculos Renais , Lactobacillus acidophilus , Lactobacillus acidophilus/metabolismo , Lactobacillus acidophilus/crescimento & desenvolvimento , Lactobacillus acidophilus/fisiologia , Oxalato de Cálcio/metabolismo , Humanos , Cálculos Renais/microbiologia , Cristalização , Glicoproteínas de Membrana/metabolismo , Flagelos
8.
Cells ; 13(17)2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39273010

RESUMO

Helicobacter pylori is a bacterial pathogen that colonizes the human stomach, where it can cause a variety of diseases. H. pylori uses a cluster of sheathed flagella for motility, which is required for host colonization in animal models. The flagellar sheath is continuous with the outer membrane and is found in most Helicobacter species identified to date. HP0018 is a predicted lipoprotein of unknown function that is conserved in Helicobacter species that have flagellar sheaths but is absent in Helicobacter species that have sheath-less flagella. Deletion of hp0018 in H. pylori B128 resulted in the formation of long chains of outer membrane vesicles, which were most evident in an aflagellated variant of the Δhp0018 mutant that had a frameshift mutation in fliP. Flagellated cells of the Δhp0018 mutant possessed what appeared to be a normal flagellar sheath, suggesting that HP0018 is not required for sheath formation. Cells of the Δhp0018 mutant were also less helical in shape compared to wild-type cells. A HP0018-superfolder green fluorescent fusion protein expressed in the H. pylori Δhp0018 mutant formed fluorescent foci at the cell poles and lateral sites. Co-immunoprecipitation assays with HP0018 identified two enzymes involved in the modification of the cell wall peptidoglycan, AmiA and MltD, as potential HP0018 interaction partners. HP0018 may modulate the activity of AmiA or MltD, and in the absence of HP0018, the unregulated activity of these enzymes may alter the peptidoglycan layer in a manner that results in an altered cell shape and hypervesiculation.


Assuntos
Flagelos , Helicobacter pylori , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Helicobacter pylori/fisiologia , Flagelos/metabolismo , Membrana Celular/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Humanos , Lipoproteínas/metabolismo , Lipoproteínas/genética
9.
Mol Plant Pathol ; 25(9): e70001, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39223938

RESUMO

Xanthomonas albilineans (Xal) is a gram-negative bacterial pathogen responsible for developing sugarcane leaf scald disease, which engenders significant economic losses within the sugarcane industry. In the current study, homologous recombination exchange was carried out to induce mutations within the virB/D4-like type IV secretion system (T4SS) genes of Xal. The results revealed that the virB11-deletion mutant (ΔvirB11) exhibited a loss in swimming and twitching motility. Application of transmission electron microscopy analysis further demonstrated that the ΔvirB11 failed to develop flagella formation and type IV pilus morphology and exhibited reduced swarming behaviour and virulence. However, these alterations had no discernible impact on bacterial growth. Comparative transcriptome analysis between the wild-type Xal JG43 and the deletion-mutant ΔvirB11 revealed 123 differentially expressed genes (DEGs), of which 28 and 10 DEGs were notably associated with flagellar assembly and chemotaxis, respectively. In light of these findings, we postulate that virB11 plays an indispensable role in regulating the processes related to motility and chemotaxis in Xal.


Assuntos
Proteínas de Bactérias , Fímbrias Bacterianas , Flagelos , Xanthomonas , Xanthomonas/patogenicidade , Xanthomonas/genética , Virulência/genética , Fímbrias Bacterianas/metabolismo , Fímbrias Bacterianas/ultraestrutura , Fímbrias Bacterianas/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/genética , Regulação Bacteriana da Expressão Gênica , Morfogênese , Doenças das Plantas/microbiologia , Saccharum/microbiologia
10.
Sci Adv ; 10(36): eadq2950, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39231220

RESUMO

Eukaryotic cilia and flagella are essential for cell motility and sensory functions. Their biogenesis and maintenance rely on the intraflagellar transport (IFT). Several cargo adapters have been identified to aid IFT cargo transport, but how ciliary cargos are discharged from the IFT remains largely unknown. During our explorations of small GTPases ARL13 and ARL3 in Trypanosoma brucei, we found that ODA16, a known IFT cargo adapter present exclusively in motile cilia, is a specific effector of ARL3. In the cilia, active ARL3 GTPases bind to ODA16 and dissociate ODA16 from the IFT complex. Depletion of ARL3 GTPases stabilizes ODA16 interaction with the IFT, leading to ODA16 accumulation in cilia and defects in axonemal assembly. The interactions between human ODA16 homolog HsDAW1 and ARL GTPases are conserved, and these interactions are altered in HsDAW1 disease variants. These findings revealed a conserved function of ARL GTPases in IFT transport of motile ciliary components, and a mechanism of cargo unloading from the IFT.


Assuntos
Fatores de Ribosilação do ADP , Cílios , Proteínas de Protozoários , Trypanosoma brucei brucei , Humanos , Fatores de Ribosilação do ADP/metabolismo , Fatores de Ribosilação do ADP/genética , Axonema/metabolismo , Transporte Biológico , Cílios/metabolismo , Flagelos/metabolismo , Ligação Proteica , Transporte Proteico , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Trypanosoma brucei brucei/metabolismo
11.
Int J Mol Sci ; 25(17)2024 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-39273173

RESUMO

Escherichia coli O157:H7 (E. coli O157) is known for causing severe foodborne illnesses such as hemorrhagic colitis and hemolytic uremic syndrome. Although E. coli O157 is typically regarded as an extracellular pathogen and a weak biofilm producer, some E. coli O157 strains, including a clinical strain ATCC 43895, exhibit a notable ability to invade bovine crypt cells and other epithelial cells, as well as to form robust biofilm. This invasive strain persists in the bovine host significantly longer than non-invasive strains. Various surface-associated factors, including lipopolysaccharides (LPS), flagella, and other adhesins, likely contribute to this enhanced invasiveness and biofilm formation. In this study, we constructed a series of LPS-core deletion mutations (waaI, waaG, waaF, and waaC) in E. coli O157 ATCC 43895, resulting in stepwise truncations of the LPS. This approach enabled us to investigate the effects on the biosynthesis of key surface factors, such as flagella and curli, and the ability of this invasive strain to invade host cells. We confirmed the LPS structure and found that all LPS-core mutants failed to form biofilms, highlighting the crucial role of core oligosaccharides in biofilm formation. Additionally, the LPS inner-core mutants ΔwaaF and ΔwaaC lost the ability to produce flagella and curli. Furthermore, these inner-core mutants exhibited a dramatic reduction in adherence to and invasion of epithelial cells (MAC-T), showing an approximately 100-fold decrease in cell invasion compared with the outer-core mutants (waaI and waaG) and the wild type. These findings underscore the critical role of LPS-core truncation in impairing flagella and curli biosynthesis, thereby reducing the invasion capability of E. coli O157 ATCC 43895.


Assuntos
Biofilmes , Escherichia coli O157 , Flagelos , Lipopolissacarídeos , Flagelos/metabolismo , Flagelos/genética , Lipopolissacarídeos/biossíntese , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Escherichia coli O157/fisiologia , Biofilmes/crescimento & desenvolvimento , Animais , Bovinos , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Aderência Bacteriana , Células Epiteliais/microbiologia , Células Epiteliais/metabolismo
12.
Proc Natl Acad Sci U S A ; 121(34): e2408551121, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39145934

RESUMO

The first steps of vision take place in the ciliary outer segment compartment of photoreceptor cells. The protein composition of outer segments is uniquely suited to perform this function. The most abundant among these proteins is the visual pigment, rhodopsin, whose outer segment trafficking involves intraflagellar transport (IFT). Here, we report three major findings from the analysis of mice in which ciliary transport was acutely impaired by conditional knockouts of IFT-B subunits. First, we demonstrate the existence of a sorting mechanism whereby mislocalized rhodopsin is recruited to and concentrated in extracellular vesicles prior to their release, presumably to protect the cell from adverse effects of protein mislocalization. Second, reducing rhodopsin expression significantly delays photoreceptor degeneration caused by IFT disruption, suggesting that controlling rhodopsin levels may be an effective therapy for some cases of retinal degenerative disease. Last, the loss of IFT-B subunits does not recapitulate a phenotype observed in mutants of the BBSome (another ciliary transport protein complex relying on IFT) in which non-ciliary proteins accumulate in the outer segment. Whereas it is widely thought that the role of the BBSome is to primarily participate in ciliary transport, our data suggest that the BBSome has another major function independent of IFT and possibly related to maintaining the diffusion barrier of the ciliary transition zone.


Assuntos
Camundongos Knockout , Rodopsina , Animais , Camundongos , Rodopsina/metabolismo , Cílios/metabolismo , Transporte Proteico , Transporte Biológico , Flagelos/metabolismo , Compartimento Celular , Vesículas Extracelulares/metabolismo
13.
Bull Math Biol ; 86(10): 125, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39214887

RESUMO

We study the stochastic hydrodynamics of colonies of flagellated swimming cells, typified by multicellular choanoflagellates, which can form both rosette and chainlike shapes. The objective is to link cell-scale dynamics to colony-scale dynamics for various colonial morphologies. Via autoregressive stochastic models for the cycle-averaged flagellar force dynamics and statistical models for demographic cell-to-cell variability in flagellar properties and placement, we derive effective transport properties of the colonies, including cell-to-cell variability. We provide the most quantitative detail on disclike geometries to model rosettes, but also present formulas for the dynamics of general planar colony morphologies, which includes planar chain-like configurations.


Assuntos
Movimento Celular , Coanoflagelados , Flagelos , Conceitos Matemáticos , Modelos Biológicos , Processos Estocásticos , Flagelos/fisiologia , Coanoflagelados/fisiologia , Coanoflagelados/citologia , Movimento Celular/fisiologia , Hidrodinâmica
14.
Microbiol Spectr ; 12(10): e0030424, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39189752

RESUMO

Atypical enteropathogenic Escherichia coli (aEPEC) is a significant cause of diarrhea in low- and middle-income countries. Certain aEPEC strains, including the Brazilian representative strain of serotype O51:H40 called aEPEC 1711-4, can use flagella to attach to, invade, and persist in T84 and Caco-2 intestinal cells. It can also translocate from the gut to extraintestinal sites in a rat model. Although various aspects of the virulence of this strain were studied and the requirement of a type III secretion system for the efficiency of the invasion process was demonstrated, the expression of the locus of enterocyte effacement (LEE) genes during the invasion and intracellular persistence remains unclear. To address this question, the expression of flagella and the different LEE operons was evaluated during kinetic experiments of the interaction of aEPEC 1711-4 with enterocytes in vitro. The genome of the strain was also sequenced. The results showed that flagella expression remained unchanged, but the expression of eae and escJ increased during the early interaction and invasion of aEPEC 1711-4 into Caco-2 cells, and there was no change 24 h post-infection during the persistence period. The number of actin accumulation foci formed on HeLa cells also increased during the 6-h analysis. No known gene related to the invasion process was identified in the genome of aEPEC 1711-4, which was shown to belong to the global EPEC lineage 10. These findings suggest that the LEE components and the intimate adherence promoted by intimin are necessary for the invasion and persistence of aEPEC 1711-4, but the detailed mechanism needs further study.IMPORTANCEAtypical enteropathogenic Escherichia coli (aEPEC) is a major cause of diarrhea, especially in low- and middle-income countries, like Brazil. However, due to the genome heterogeneity of each clonal group, it is difficult to comprehend the pathogenicity of this strain fully. Among aEPEC strains, 1711-4 can invade eukaryotic cells in vitro, cross the gut barrier, and reach extraintestinal sites in animal models. By studying how different known aEPEC virulence factors are expressed during the invasion process, we can gain insight into the commonalities of this phenotype among other aEPEC strains. This will help in developing preventive measures to control infections caused by invasive strains. No known virulence-encoding genes linked to the invasion process were found. Nevertheless, additional studies are still necessary to evaluate the role of other factors in this phenotype.


Assuntos
Enterócitos , Escherichia coli Enteropatogênica , Infecções por Escherichia coli , Proteínas de Escherichia coli , Flagelos , Sorogrupo , Escherichia coli Enteropatogênica/genética , Escherichia coli Enteropatogênica/patogenicidade , Escherichia coli Enteropatogênica/metabolismo , Humanos , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Enterócitos/microbiologia , Células CACO-2 , Infecções por Escherichia coli/microbiologia , Flagelos/genética , Flagelos/metabolismo , Virulência/genética , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Regulação Bacteriana da Expressão Gênica , Aderência Bacteriana/genética , Animais , Brasil , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Óperon/genética , Ratos
15.
Langmuir ; 40(33): 17731-17739, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39108086

RESUMO

Artificial bacterial flagella (ABF), also known as a magnetic helical microswimmer, has demonstrated enormous potential in various future biomedical applications (e.g., targeted drug delivery and minimally invasive surgery). Nevertheless, when used for in vivo/in vitro treatment applications, it is essential to achieve the high motion efficiency of the microswimmers for rapid therapy. In this paper, inspired by microorganisms, the surface microstructure was introduced into ABFs to investigate its effect on the swimming behavior. It was confirmed that compared with smooth counterparts, the ABF with surface microstructure reveals a smaller forward velocity below the step-out frequency (i.e., the frequency corresponding to the maximum velocity) but a larger maximum forward velocity and higher step-out frequency. A hydrodynamic model of microstructured ABF is employed to reveal the underlying movement mechanism, demonstrating that the interfacial slippage and the interaction between the fluid and the microstructure are essential to the swimming behavior. Furthermore, the effect of surface wettability and solid fraction of microstructure on the swimming performance of ABFs was investigated experimentally and analytically, which further reveals the influence of surface microstructure on the movement mechanism. The results present an effective approach for designing fast microrobots for in vivo/in vitro biomedical applications.


Assuntos
Propriedades de Superfície , Flagelos , Molhabilidade , Hidrodinâmica , Natação
16.
Nat Commun ; 15(1): 6960, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39138209

RESUMO

Leishmania species, members of the kinetoplastid parasites, cause leishmaniasis, a neglected tropical disease, in millions of people worldwide. Leishmania has a complex life cycle with multiple developmental forms, as it cycles between a sand fly vector and a mammalian host; understanding their life cycle is critical to understanding disease spread. One of the key life cycle stages is the haptomonad form, which attaches to insect tissues through its flagellum. This adhesion, conserved across kinetoplastid parasites, is implicated in having an important function within their life cycles and hence in disease transmission. Here, we discover the kinetoplastid-insect adhesion proteins (KIAPs), which localise in the attached Leishmania flagellum. Deletion of these KIAPs impairs cell adhesion in vitro and prevents Leishmania from colonising the stomodeal valve in the sand fly, without affecting cell growth. Additionally, loss of parasite adhesion in the sand fly results in reduced physiological changes to the fly, with no observable damage of the stomodeal valve and reduced midgut swelling. These results provide important insights into a comprehensive understanding of the Leishmania life cycle, which will be critical for developing transmission-blocking strategies.


Assuntos
Flagelos , Leishmania , Psychodidae , Animais , Leishmania/fisiologia , Leishmania/genética , Leishmania/metabolismo , Psychodidae/parasitologia , Flagelos/metabolismo , Adesão Celular , Insetos Vetores/parasitologia , Interações Hospedeiro-Parasita , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Estágios do Ciclo de Vida , Leishmaniose/parasitologia , Leishmaniose/transmissão , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Feminino
17.
Biosci Rep ; 44(9)2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39105472

RESUMO

Motility by means of flagella plays an important role in the persistent colonization of Helicobacter pylori in the human stomach. The H. pylori flagellar motor has a complex structure that includes a periplasmic scaffold, the components of which are still being identified. Here, we report the isolation and characterization of the soluble forms of two putative essential H. pylori motor scaffold components, proteins PflA and PflB. We developed an on-column refolding procedure, overcoming the challenge of inclusion body formation in Escherichia coli. We employed mild detergent sarkosyl to enhance protein recovery and n-dodecyl-N,N-dimethylamine-N-oxide (LDAO)-containing buffers to achieve optimal solubility and monodispersity. In addition, we showed that PflA lacking the ß-rich N-terminal domain is expressed in a soluble form, and behaves as a monodisperse monomer in solution. The methods for producing the soluble, folded forms of H. pylori PflA and PflB established in this work will facilitate future biophysical and structural studies aimed at deciphering their location and their function within the flagellar motor.


Assuntos
Proteínas de Bactérias , Flagelos , Helicobacter pylori , Helicobacter pylori/metabolismo , Flagelos/metabolismo , Flagelos/química , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Solubilidade , Escherichia coli/genética , Escherichia coli/metabolismo , Dobramento de Proteína , Humanos , Proteínas Motores Moleculares/metabolismo , Proteínas Motores Moleculares/química , Proteínas Motores Moleculares/genética , Sarcosina/análogos & derivados
18.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-39113613

RESUMO

Biofilms aid bacterial adhesion to surfaces via direct and indirect mechanisms, and formation of biofilms is considered as an important strategy for adaptation and survival in suboptimal environmental conditions. However, the molecular underpinnings of biofilm formation in subsurface sediment/groundwater ecosystems where microorganisms often experience fluctuations in nutrient input, pH, and nitrate or metal concentrations are underexplored. We examined biofilm formation under different nutrient, pH, metal, and nitrate regimens of 16 Rhodanobacter strains isolated from subsurface groundwater wells spanning diverse levels of pH (3.5 to 5) and nitrates (13.7 to 146 mM). Eight Rhodanobacter strains demonstrated significant biofilm growth under low pH, suggesting adaptations for survival and growth at low pH. Biofilms were intensified under aluminum stress, particularly in strains possessing fewer genetic traits associated with biofilm formation, findings warranting further investigation. Through random barcode transposon-site sequencing (RB-TnSeq), proteomics, use of specific mutants, and transmission electron microscopy analysis, we discovered flagellar loss under aluminum stress, indicating a potential relationship between motility, metal tolerance, and biofilm growth. Comparative genomic analyses revealed the absence of flagella and chemotaxis genes and the presence of a putative type VI secretion system in the highly biofilm-forming strain FW021-MT20. In this study we identified genetic determinants associated with biofilm growth under metal stress in a predominant environmental genus, Rhodanobacter, and identified traits aiding survival and adaptation to contaminated subsurface environments.


Assuntos
Adaptação Fisiológica , Alumínio , Biofilmes , Flagelos , Estresse Fisiológico , Biofilmes/crescimento & desenvolvimento , Flagelos/genética , Flagelos/fisiologia , Alumínio/toxicidade , Concentração de Íons de Hidrogênio , Nitratos/metabolismo , Água Subterrânea/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
19.
Int J Mol Sci ; 25(16)2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39201530

RESUMO

The rise of antibiotic tolerance in bacteria harboring genetic elements conferring resistance to antibiotics poses an increasing threat to public health. However, the primary factors responsible for the emergence of antibiotic tolerance and the fundamental molecular mechanisms involved remain poorly comprehended. Here, we demonstrate that the commonly utilized food additive Benzaldehyde (BZH) possesses the capacity to induce a significant level of fluoroquinolone tolerance in vitro among resistant Escherichia coli. Our findings from animal models reveal that the pre-administration of BZH results in an ineffective eradication of bacteria through ciprofloxacin treatment, leading to similar survival rates and bacterial loads as observed in the control group. These results strongly indicate that BZH elicits in vivo tolerance. Mechanistic investigations reveal several key factors: BZH inhibits the formation of bacterial flagella and releases proton motive force (PMF), which aids in expelling antibiotics from within cells to reducing their accumulation inside. In addition, BZH suppresses bacterial respiration and inhibits the production of reactive oxygen species (ROS). Moreover, exogenous pyruvate successfully reverses BZH-induced tolerance and restores the effectiveness of antibiotics, highlighting how crucial the pyruvate cycle is in combating antibiotic tolerance. The present findings elucidate the underlying mechanisms of BZH-induced tolerance and highlight potential hazards associated with the utilization of BZH.


Assuntos
Antibacterianos , Benzaldeídos , Escherichia coli , Flagelos , Benzaldeídos/farmacologia , Flagelos/efeitos dos fármacos , Flagelos/metabolismo , Antibacterianos/farmacologia , Animais , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Escherichia coli/genética , Aditivos Alimentares/farmacologia , Aditivos Alimentares/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Camundongos , Testes de Sensibilidade Microbiana
20.
J Cell Biol ; 223(9)2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39110193

RESUMO

Intraflagellar transport has traditionally been studied in immobilized flagella. In this issue, Gray et al. (https://doi.org/10.1083/jcb.202401154) introduced a novel methodology for fast imaging in free-swimming Leishmania, revealing the impacts of flagellum immobilization on intraflagellar transport and its inverse correlation with cell swimming speed.


Assuntos
Flagelos , Flagelos/metabolismo , Flagelos/ultraestrutura , Leishmania , Transporte Biológico
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