Publications by authors named "Ana do Vale"

Introduction: Despite being a bacterial pathogen with devastating consequences, 's pathogenesis is not fully understood. The aim of the present study was to elucidate if different inoculation routes (intraperitoneal - i.p - injection and bath challenge - known to induce mortality) can induce tenacibaculosis (i.

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The high-pathogenicity island -HPI is widespread in and encodes the siderophore piscibactin, as well as the regulator PbtA that is essential for its expression. In this work, we aim to study whether PbtA directly interacts with -HPI promoters. Furthermore, we hypothesize that PbtA, and thereby the acquisition of -HPI island, may also influence the expression of other genes elsewhere in the bacterial genome.

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Bacterial AB toxins are secreted key virulence factors that are internalized by target cells through receptor-mediated endocytosis, translocating their enzymatic domain to the cytosol from endosomes (short-trip) or the endoplasmic reticulum (long-trip). To accomplish this, bacterial AB toxins evolved a multidomain structure organized into either a single polypeptide chain or non-covalently associated polypeptide chains. The prototypical short-trip single-chain toxin is characterized by a receptor-binding domain that confers cellular specificity and a translocation domain responsible for pore formation whereby the catalytic domain translocates to the cytosol in an endosomal acidification-dependent way.

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Article Synopsis
  • The study investigates tenacibaculosis, a bacterial disease affecting European sea bass, focusing on the early immune response triggered by infection.
  • Researchers exposed sea bass to the pathogen and collected samples from blood and various organs at different time points to analyze immune-related gene expression and other health metrics.
  • Results showed a significant pro-inflammatory response in mucosal organs and systemic changes, like increased white blood cell counts and signs of anemia, indicating the pathogen's capacity to harm vital body systems.
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Facultative marine bacterial pathogens sense environmental signals so that the expression of virulence factors is upregulated on entry into hosts and downregulated during the free-living lifestyle in the environment. In this study, we utilized transcriptome sequencing to compare the transcriptional profiles of subsp. , a generalist pathogen that causes disease in diverse marine animals and fatal infections in humans at NaCl concentrations that mimic the free-living lifestyle or host internal milieu, respectively.

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subsp. () is a Gram-negative fish pathogen with worldwide distribution and broad host specificity that causes heavy economic losses in aquaculture. Although was first identified more than 50 years ago, its pathogenicity mechanisms are not completely understood.

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Article Synopsis
  • - The study investigates the prevalence and causes of medication administration errors in a Brazilian university hospital, finding a high error rate of 36.2% among 561 observed drug doses.
  • - Direct observation by trained professionals over 15 days revealed that interruptions, route of administration, and workload were significant factors contributing to these errors.
  • - The findings align with other research on medication errors worldwide, highlighting the need for improved practices to reduce these harmful incidents in healthcare settings.
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subsp. () is a Gram-negative bacterium that infects a large number of marine fish species in Europe, Asia, and America, both in aquacultures and in the natural environment. Among the affected hosts are economically important cultured fish, such as sea bream (), sea bass (), yellowtail (), and cobia ().

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The marine bacterium Photobacterium damselae subsp. damselae (Pdd) causes disease in marine animals and humans. Previous studies demonstrated that mutation of the two-component system RstAB strongly impacts virulence of this pathogen, but the RstAB regulon has not been thoroughly elucidated.

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Peptidoglycan (PG) is a major component of the bacterial cell wall, forming a mesh-like structure enwrapping the bacteria that is essential for maintaining structural integrity and providing support for anchoring other components of the cell envelope. PG biogenesis is highly dynamic and requires multiple enzymes, including several hydrolases that cleave glycosidic or amide bonds in the PG. This work describes the structural and functional characterization of an NlpC/P60-containing peptidase from subsp.

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Apoptosis-inducing protein of 56 kDa (AIP56) is a major virulence factor of Photobacterium damselae subsp. piscicida, a gram-negative pathogen that infects warm water fish species worldwide and causes serious economic losses in aquacultures. AIP56 is a single-chain AB toxin composed by two domains connected by an unstructured linker peptide flanked by two cysteine residues that form a disulphide bond.

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AIP56 (apoptosis inducing protein of 56 kDa) is a key virulence factor secreted by virulent strains of Photobacterium damselae subsp. piscicida (Phdp), a Gram-negative bacterium that causes septicemic infections in several warm water marine fish species. AIP56 is systemically disseminated during infection and induces massive apoptosis of host macrophages and neutrophils, playing a decisive role in the disease outcome.

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Article Synopsis
  • The RstB histidine kinase in the RstAB system regulates the expression of key cytotoxins (Dly, PhlyP, PhlyC) in a marine bacterium that affects fish and humans, but the role of its partner response regulator RstA remains unexamined.
  • Mutations in the RstA and RstB genes decreased virulence in fish, impaired hemolysis, and affected phospholipase and gelatinase activities, indicating their significance in the bacterium's pathogenicity.
  • Analysis of T2SS-dependent proteins highlighted the RstAB system's pivotal role in virulence and identified additional potential virulence factors, suggesting a complex regulatory network influencing diverse
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subsp. () is responsible for disease outbreaks in marine aquaculture worldwide. , a valuable fish species for aquaculture in the south of Europe, is frequently affected by this pathogen.

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AIP56 (apoptosis-inducing protein of 56 kDa) is a key virulence factor of subsp. the causative agent of a septicaemia affecting warm water marine fish species. -associated pathology is triggered by AIP56, a short trip AB toxin with a metalloprotease A domain that cleaves the p65 subunit of NF-κB, an evolutionarily conserved transcription factor that regulates the expression of inflammatory and anti-apoptotic genes and plays a central role in host responses to infection.

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Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favor microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils.

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AIP56 (apoptosis-inducing protein of 56 kDa) is a metalloprotease AB toxin secreted by Photobacterium damselae subsp. piscicida that acts by cleaving NF-κB. During infection, AIP56 spreads systemically and depletes phagocytes by postapoptotic secondary necrosis, impairing the host phagocytic defense and contributing to the genesis of infection-associated necrotic lesions.

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AIP56 (apoptosis-inducing protein of 56 kDa) is a major virulence factor of Photobacterium damselae piscicida (Phdp), a Gram-negative pathogen that causes septicemic infections, which are among the most threatening diseases in mariculture. The toxin triggers apoptosis of host macrophages and neutrophils through a process that, in vivo, culminates with secondary necrosis of the apoptotic cells contributing to the necrotic lesions observed in the diseased animals. Here, we show that AIP56 is a NF-κB p65-cleaving zinc-metalloprotease whose catalytic activity is required for the apoptogenic effect.

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Interleukine-1β (IL-1β) is the most studied pro-inflammatory cytokine, playing a central role in the generation of systemic and local responses to infection, injury, and immunological challenges. In mammals, IL-1β is synthesized as an inactive 31 kDa precursor that is cleaved by caspase-1 generating a 17.5 kDa secreted active mature form.

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It has been previously shown that the exotoxin of the important fish pathogen Photobacterium damselae ssp. piscicida is a key pathogenicity factor and is responsible for the extensive systemic apoptosis of macrophages and neutrophils seen in acute fish photobacteriosis. The focus of the present study was to further characterize the AIP56-induced apoptosis of sea bass professional phagocytes by assessing the involvement of caspases, mitochondria and oxidative stress.

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Photobacterium damselae subsp. piscicida (Phdp) is a Gram-negative pathogen agent of an important fish septicemia. The key virulence factor of Phdp is the plasmid-encoded exotoxin AIP56, which is secreted by exponentially growing pathogenic strains.

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Caspase-8 is an initiator caspase that plays a crucial role in some cases of apoptosis by extrinsic and intrinsic pathways. Caspase-8 structure and function have been extensively studied in mammals, but in fish the characterization of that initiator caspase is still scarce. In this work, the sea bass counterpart of mammalian caspase-8 was sequenced and characterized, and its involvement in the apoptogenic activity of a toxin from a fish pathogen was assessed.

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In metazoans apoptosis is a major physiological process of cell elimination during development and in tissue homeostasis and can be involved in pathological situations. In vitro, apoptosis proceeds through an execution phase during which cell dismantling is initiated, with or without fragmentation into apoptotic bodies, but with maintenance of a near-to-intact cytoplasmic membrane, followed by a transition to a necrotic cell elimination traditionally called "secondary necrosis". Secondary necrosis involves activation of self-hydrolytic enzymes, and swelling of the cell or of the apoptotic bodies, generalized and irreparable damage to the cytoplasmic membrane, and culminates with cell disruption.

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