inhibits nuclear translocation of TFEB, the master transcription factor for lysosomal biogenesis.

Unlabelled: is a highly infectious, Gram-negative, obligate intracellular bacterium and the causative agent of human Q fever. The Containing Vacuole (CCV) is a modified phagolysosome that forms through fusion with host endosomes and lysosomes. While an initial acidic pH < 4.

Metabolism and physiology of pathogenic bacterial obligate intracellular parasites.

Bacterial obligate intracellular parasites (BOIPs) represent an exclusive group of bacterial pathogens that all depend on invasion of a eukaryotic host cell to reproduce. BOIPs are characterized by extensive adaptation to their respective replication niches, regardless of whether they replicate within the host cell cytoplasm or within specialized replication vacuoles. Genome reduction is also a hallmark of BOIPs that likely reflects streamlining of metabolic processes to reduce the need for biosynthesis of energetically costly metabolic intermediates.

Sting mediates infection by reducing accumulation of reactive oxygen species.

The Gram-negative bacterium is the causative agent of query fever in humans and coxiellosis in livestock. infects a variety of cell types, tissues, and animal species including mammals and arthropods, but there is much left to be understood about the molecular mechanisms at play during infection in distinct species. Human stimulator of interferon genes (STING) induces an innate immune response through the induction of type I interferons (IFNs), and IFN promotes or suppresses replication, depending on tissue type.

Natural reversion promotes LPS elongation in an attenuated Coxiella burnetii strain.

Lipopolysaccharide (LPS) phase variation is a critical aspect of virulence in many Gram-negative bacteria. It is of particular importance to Coxiella burnetii, the biothreat pathogen that causes Q fever, as in vitro propagation of this organism leads to LPS truncation, which is associated with an attenuated and exempted from select agent status (Nine Mile II, NMII). Here, we demonstrate that NMII was recovered from the spleens of infected guinea pigs.

Expression and structure of the Chlamydia trachomatis DksA ortholog.

Chlamydia trachomatis is a bacterial obligate intracellular parasite and a significant cause of human disease, including sexually transmitted infections and trachoma. The bacterial RNA polymerase-binding protein DksA is a transcription factor integral to the multicomponent bacterial stress response pathway known as the stringent response. The genome of C.

Metabolic Plasticity Aids Amphotropism of Coxiella burnetii.

Coxiella burnetii, the causative agent of query (Q) fever in humans, is an obligate intracellular bacterium. C. burnetii can naturally infect a broad range of host organisms (e.

The sRNA Regulated Protein DdbA Is Involved in Development and Maintenance of the Chlamydia trachomatis EB Cell Form.

The chlamydial small non coding RNA, IhtA, regulates the expression of both HctA and DdbA, the uncharacterized product of the C. trachomatis L2 CTL0322 gene. HctA is a small, highly basic, DNA binding protein that is expressed late in development and mediates the condensation of the genome during RB to EB differentiation.

Conditional impairment of Coxiella burnetii by glucose-6P dehydrogenase activity.

Coxiella burnetii is a bacterial obligate intracellular parasite and the etiological agent of query (Q) fever. While the C. burnetii genome has been reduced to ∼2 Mb as a likely consequence of genome streamlining in response to parasitism, enzymes for a nearly complete central metabolic machinery are encoded by the genome.

Natural genetic variation in Drosophila melanogaster reveals genes associated with Coxiella burnetii infection.

The gram-negative bacterium Coxiella burnetii is the causative agent of Query (Q) fever in humans and coxiellosis in livestock. Host genetics are associated with C. burnetii pathogenesis both in humans and animals; however, it remains unknown if specific genes are associated with severity of infection.

Growth of 'Candidatus Liberibacter asiaticus' in a host-free microbial culture is associated with microbial community composition.

'Candidatus Liberibacter asiaticus' ('Ca. L. asiaticus'), the suspected causative agent of citrus greening disease, is one of many phloem-restricted plant pathogens that have not been isolated and grown in an axenic culture.

Single-Inclusion Kinetics of Development.

The obligate intracellular bacterial pathogen is reliant on a developmental cycle consisting of two cell forms, termed the elementary body (EB) and the reticulate body (RB). The EB is infectious and utilizes a type III secretion system and preformed effector proteins during invasion, but it does not replicate. The RB replicates in the host cell but is noninfectious.

Selective Inhibition of Coxiella burnetii Replication by the Steroid Hormone Progesterone.

is a zoonotic bacterial obligate intracellular parasite and the cause of query (Q) fever. During natural infection of female animals, shows tropism for the placenta and is associated with late-term abortion, at which time the pathogen titer in placental tissue can exceed one billion bacteria per gram. During later stages of pregnancy, placental trophoblasts serve as the major source of progesterone, a steroid hormone known to affect the replication of some pathogens.

Critical Role for Molecular Iron in Coxiella burnetii Replication and Viability.

, the causative agent of Query (Q) fever in humans, is a highly infectious obligate intracellular bacterium. Following uptake into a host cell, replicates within a phagolysosome-derived compartment referred to as the -containing vacuole (CCV). During infection, exhibits tropism for tissues related to iron storage and recycling (e.

Controlled replication of 'Candidatus Liberibacter asiaticus' DNA in citrus leaf discs.

'Candidatus Liberibacter asiaticus' is a fastidious bacterium and a putative agent of citrus greening disease (a.k.a.

Physiochemical changes mediated by "Candidatus Liberibacter asiaticus" in Asian citrus psyllids.

Plant pathogenic bacteria interact with their insect host(s)/vector(s) at the cellular and molecular levels. This interaction may alter the physiology of their insect vector, which may also promote the growth and transmission of the bacterium. Here we studied the effect of "Candidatus Liberibacter asiaticus" ("Ca.

Host-free biofilm culture of " Liberibacter asiaticus," the bacterium associated with Huanglongbing.

Inability to culture the phloem-restricted alpha-proteobacterium " Liberibacter asiaticus" (" L. asiaticus") or the closely related species (" Liberibacter americanus" and " Liberibacter africanus") that are associated with Huanglongbing (HLB) hampers the development of effective long-term control strategies for this devastating disease. Here we report successful establishment and long-term maintenance of host-free " L.

The infection of its insect vector by bacterial plant pathogen "Candidatus Liberibacter solanacearum" is associated with altered vector physiology.

Many bacterial and viral plant pathogens are transmitted by insect vectors, and pathogen-mediated alterations of plant physiology often influence insect vector behavior and fitness. It remains largely unknown for most plant pathogens whether, and how, they might directly alter the physiology of their insect vectors in ways that promote pathogen transmission. Here we examined whether the presence of "Candidatus Liberibacter solanacearum" ("Ca.

Lipid A Has Significance for Optimal Growth of in Macrophage-Like THP-1 Cells and to a Lesser Extent in Axenic Media and Non-phagocytic Cells.

Lipid A is an essential basal component of lipopolysaccharide of most Gram-negative bacteria. Inhibitors targeting LpxC, a conserved enzyme in lipid A biosynthesis, are antibiotic candidates against Gram-negative pathogens. Here we report the characterization of the role of lipid A in growth in axenic media, monkey kidney cells (BGMK and Vero), and macrophage-like THP-1 cells by using a potent LpxC inhibitor -LPC-011.

Use of Axenic Culture Tools to Study Coxiella burnetii.

Coxiella burnetii is a highly infectious obligate intracellular bacterium and the etiological agent of the zoonosis Query (Q) fever. This Gram-negative gamma-proteobacterium has adapted to replicate within a specialized compartment in mammalian phagocytic cells, known as the Coxiella-containing vacuole (CCV). Knowledge of critical characteristics of the CCV microenvironment (e.

Protein and DNA synthesis demonstrated in cell-free Ehrlichia chaffeensis organisms in axenic medium.

Ehrlichia chaffeensis, a tick-transmitted rickettsial bacterium, is the causative agent of human monocytic ehrlichiosis. Biochemical characterization of this and other related Rickettsiales remains a major challenge, as they require a host cell for their replication. We investigated the use of an axenic medium for E.

Impact of Active Metabolism on Chlamydia trachomatis Elementary Body Transcript Profile and Infectivity.

Bacteria of the genus include the significant human pathogens and All chlamydiae are obligate intracellular parasites that depend on infection of a host cell and transition through a biphasic developmental cycle. Following host cell invasion by the infectious elementary body (EB), the pathogen transitions to the replicative but noninfectious reticulate body (RB). Differentiation of the RB back to the EB is essential to generate infectious progeny.

Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.

Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin).