Identification and pathogenicity of and species associated with bagged apple black spot disease in Shaanxi, China.

Apple is an economically important fruit crop in northern Shaanxi Province in China. In recent years, a new type of apple black spot disease, "bagged apple black spot disease," has occurred in the main apple production area of Yan'an City, Shaanxi Province, during the apple ripening season. It seriously affects the appearance quality and commercial value of apples.

Relationship between Pyochelin and Quinolone Signal in : A Direction for Future Research.

is an opportunistic pathogen that requires iron to survive in the host; however, the host immune system limits the availability of iron. Pyochelin (PCH) is a major siderophore produced by during infection, which can help survive in an iron-restricted environment and cause infection. The infection activity of is regulated by the quinolone signal (PQS) quorum-sensing system.

Paralytic shellfish toxins producing dinoflagellates cause dysbacteriosis in scallop gut microbial biofilms.

Filter-feeding bivalves could accumulate paralytic shellfish toxins (PSTs) produced by harmful dinoflagellates through diet. Despite that bivalves are resistant to these neurotoxins due to possessing PST-resistant sodium channel, exposure to PSTs-producing dinoflagellates impair bivalve survival. We hypothesized that ingesting PSTs-producing dinoflagellates may influence the gut microbiota, and then the health of bivalves.

The role of the type VI secretion system in the stress resistance of plant-associated bacteria.

The type VI secretion system (T6SS) is a powerful bacterial molecular weapon that can inject effector proteins into prokaryotic or eukaryotic cells, thereby participating in the competition between bacteria and improving bacterial environmental adaptability. Although most current studies of the T6SS have focused on animal bacteria, this system is also significant for the adaptation of plant-associated bacteria. This paper briefly introduces the structure and biological functions of the T6SS.

PQS and pyochelin in share inner membrane transporters to mediate iron uptake.

Bacteria absorb different forms of iron through various channels to meet their needs. Our previous studies have shown that TseF, a type VI secretion system effector for Fe uptake, facilitates the delivery of outer membrane vesicle-associated quinolone signal (PQS)-Fe to bacterial cells by a process involving the Fe(III) pyochelin receptor FptA and the porin OprF. However, the form in which the PQS-Fe complex enters the periplasm and how it is moved into the cytoplasm remain unclear.

Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention.

Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as venous ducts, joint prostheses, mechanical heart valves, and catheters. Biofilms provide a protective barrier for bacteria and provide resistance to antimicrobial agents, which increases the morbidity and mortality of patients.

H3-T6SS Combats HO Stress by Diminishing the Amount of Intracellular Unincorporated Iron in a Dps-Dependent Manner and Inhibiting the Synthesis of PQS.

The type VI secretion system (T6SS), a protein translocation nanomachine, is widely distributed in Gram-negative bacteria and delivers effectors directly into target cells or the extracellular environment to help the bacteria gain a competitive fitness advantage and promote bacterial survival in harmful environments. In this study, we demonstrated that the synthesis of the quinolone signal (PQS) in PAO1 was inhibited by the H3-T6SS gene cluster under iron-rich conditions, and that this inhibition was relieved under iron starvation conditions. Conversely, PQS differentially regulated the expression of the H3-T6SS structural genes and the effector protein gene .

Treatment of infectious biofilms: Challenges and strategies.

, a Gram-negative bacterium, is one of the major pathogens implicated in human opportunistic infection and a common cause of clinically persistent infections such as cystic fibrosis, urinary tract infections, and burn infections. The main reason for the persistence of infections is due to the ability of to secrete extracellular polymeric substances such as exopolysaccharides, matrix proteins, and extracellular DNA during invasion. These substances adhere to and wrap around bacterial cells to form a biofilm.

Beyond dueling: roles of the type VI secretion system in microbiome modulation, pathogenesis and stress resistance.

Bacteria inhabit diverse and dynamic environments, where nutrients may be limited and toxic chemicals can be prevalent. To adapt to these stressful conditions, bacteria have evolved specialized protein secretion systems, such as the type VI secretion system (T6SS) to facilitate their survival. As a molecular syringe, the T6SS expels various effectors into neighboring bacterial cells, eukaryotic cells, or the extracellular environment.

Manipulation of the silkworm immune system by a metalloprotease from the pathogenic bacterium Pseudomonas aeruginosa.

Antimicrobial peptide (AMP) production and melanization are two key humoral immune responses in insects. Induced synthesis of AMPs results from Toll and IMD signal transduction whereas melanization depends on prophenoloxidase (PPO) activation system. During invasion, pathogens produce toxins and other virulent factors to counteract host immune responses.

The Quinolone Signal (PQS): Not Just for Quorum Sensing Anymore.

The quinolone signal (PQS) has been studied primarily in the context of its role as a quorum-sensing signaling molecule. Recent data suggest, however, that this molecule may also function to mediate iron acquisition, cytotoxicity, outer-membrane vesicle biogenesis, or to exert host immune modulatory activities.

A Pseudomonas T6SS effector recruits PQS-containing outer membrane vesicles for iron acquisition.

Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P.

Functional Characterization of Triclosan-Resistant Enoyl-acyl-carrier Protein Reductase (FabV) in .

is extremely resistant to triclosan. Previous studies have shown that encodes a triclosan-resistant enoyl-acyl-carrier protein reductase (ENR), FabV, and that deletion of causes to be extremely sensitive to triclosan. In this report, we complemented a deletion strain with several triclosan-resistant ENR encoding genes, including and .

Graded Response of the Multifunctional 2-Cysteine Peroxiredoxin, CgPrx, to Increasing Levels of Hydrogen Peroxide in Corynebacterium glutamicum.

Aims: Eukaryotic typical 2-cysteine (Cys) peroxiredoxins (Prxs) are multifunctional proteins subjected to complex regulation and play important roles in oxidative stress resistance, hydrogen peroxide (HO) signaling modulation, aging, and cancer, but the information on the biochemical functions and regulation mechanisms of prokaryotic atypical 2-Cys Prxs is largely lacking.

Results: In this study, we show that at low peroxide concentrations, the atypical 2-Cys Prx in Corynebacterium glutamicum (CgPrx) mainly exists as monomers and displays thioredoxin (Trx)-dependent peroxidase activity. Moderate oxidative stress causes reversible S-mycothiolation of the HO-sensing Cys63 residue, which keeps CgPrx exclusively in dimer form with neither peroxidase nor chaperone activity.

Mycothiol protects Corynebacterium glutamicum against acid stress via maintaining intracellular pH homeostasis, scavenging ROS, and S-mycothiolating MetE.

Mycothiol (MSH) plays a major role in protecting cells against oxidative stress and detoxification from a broad range of exogenous toxic agents. In the present study, we reveal that intracellular MSH contributes significantly to the adaptation to acidic conditions in the model organism Corynebacterium glutamicum. We present evidence that MSH confers C.

The icmF3 locus is involved in multiple adaptation- and virulence-related characteristics in Pseudomonas aeruginosa PAO1.

The type VI secretion system (T6SS) is widely distributed in Gram-negative bacteria. Three separate T6SSs called H1-, H2-, and H3-T6SS have been discovered in Pseudomonas aeruginosa PAO1. Recent studies suggest that, in contrast to the H1-T6SS that targets prokaryotic cells, H2- and H3-T6SS are involved in interactions with both prokaryotic and eukaryotic cells.

Extracellular matrix-associated proteins form an integral and dynamic system during Pseudomonas aeruginosa biofilm development.

Though the essential role of extracellular matrix in biofilm development has been extensively documented, the function of matrix-associated proteins is elusive. Determining the dynamics of matrix-associated proteins would be a useful way to reveal their functions in biofilm development. Therefore, we applied iTRAQ-based quantitative proteomics to evaluate matrix-associated proteins isolated from different phases of Pseudomonas aeruginosa ATCC27853 biofilms.

Only one of the five Ralstonia solanacearum long-chain 3-ketoacyl-acyl carrier protein synthase homologues functions in fatty acid synthesis.

Ralstonia solanacearum, a major phytopathogenic bacterium, causes a bacterial wilt disease in diverse plants. Although fatty acid analyses of total membranes of R. solanacearum showed that they contain primarily palmitic (C(16:0)), palmitoleic (C(16:1)) and cis-vaccenic (C(18:1)) acids, little is known regarding R.

Triclosan resistance of Pseudomonas aeruginosa PAO1 is due to FabV, a triclosan-resistant enoyl-acyl carrier protein reductase.

Triclosan, a very widely used biocide, specifically inhibits fatty acid synthesis by inhibition of enoyl-acyl carrier protein (ACP) reductase. Escherichia coli FabI is the prototypical triclosan-sensitive enoyl-ACP reductase, and E. coli is extremely sensitive to the biocide.

Functions of the Clostridium acetobutylicium FabF and FabZ proteins in unsaturated fatty acid biosynthesis.

Background: The original anaerobic unsaturated fatty acid biosynthesis pathway proposed by Goldfine and Bloch was based on in vivo labeling studies in Clostridium butyricum ATCC 6015 (now C. beijerinckii) but to date no dedicated unsaturated fatty acid biosynthetic enzyme has been identified in Clostridia. C.