Studies on the cyst stage of Naegleria fowleri in vivo and in vitro.

Naegleria fowleri is a pathogenic, free-living amoeba that causes primary amebic meningoencephalitis (PAM), a highly fatal disease of the central nervous system. N. fowleri demonstrates three forms: the trophozoite, flagellate, and cyst.

Genomics and transcriptomics yields a system-level view of the biology of the pathogen Naegleria fowleri.

Background: The opportunistic pathogen Naegleria fowleri establishes infection in the human brain, killing almost invariably within 2 weeks. The amoeba performs piece-meal ingestion, or trogocytosis, of brain material causing direct tissue damage and massive inflammation. The cellular basis distinguishing N.

The Effect of Different Environmental Conditions on the Viability of Naegleria fowleri Amoebae.

Naegleria fowleri, a free-living amoeba found in soil and freshwater environments, is the causative agent of Primary Amoebic Meningoencephalitis. Infection occurs when amoebae enter the nasal cavity, attach to the nasal mucosa and travel along olfactory neurons towards the olfactory bulb. Upon reaching the central nervous system, the amoebae replicate very rapidly and can cause death in 3-10 days.

Expression of matrix metalloproteinases in Naegleria fowleri and their role in invasion of the central nervous system.

Naegleria fowleri is a free-living amoeba found in freshwater lakes and ponds and is the causative agent of primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system (CNS). PAM occurs when amoebae attach to the nasal epithelium and invade the CNS, a process that involves binding to, and degradation of, extracellular matrix (ECM) components. This degradation is mediated by matrix metalloproteinases (MMPs), enzymes that have been described in other pathogenic protozoa, and that have been linked to their increased motility and invasive capability.

Identification of Naegleria fowleri proteins linked to primary amoebic meningoencephalitis.

Naegleria fowleri (N. fowleri) causes primary amoebic meningoencephalitis, a rapidly fatal disease of the central nervous system. N.

Identification of peptidases in highly pathogenic vs. weakly pathogenic Naegleria fowleri amebae.

Naegleria fowleri, a free-living ameba, is the causative agent of Primary Amebic Meningoencephalitis. Highly pathogenic mouse-passaged amebae (Mp) and weakly pathogenic axenically grown (Ax) N. fowleri were examined for peptidase activity.

SJL mice infected with Acanthamoeba castellanii develop central nervous system autoimmunity through the generation of cross-reactive T cells for myelin antigens.

We recently reported that Acanthamoeba castellanii (ACA), an opportunistic pathogen of the central nervous system (CNS) possesses mimicry epitopes for proteolipid protein (PLP) 139-151 and myelin basic protein 89-101, and that the epitopes induce experimental autoimmune encephalomyelitis (EAE) in SJL mice reminiscent of the diseases induced with their corresponding cognate peptides. We now demonstrate that mice infected with ACA also show the generation of cross-reactive T cells, predominantly for PLP 139-151, as evaluated by T cell proliferation and IAs/dextramer staining. We verified that PLP 139-151-sensitized lymphocytes generated in infected mice contained a high proportion of T helper 1 cytokine-producing cells, and they can transfer disease to naïve animals.

Cannabinoid inhibits HIV-1 Tat-stimulated adhesion of human monocyte-like cells to extracellular matrix proteins.

Aims: The aim of this study was to assess the effect of select cannabinoids on human immunodeficiency virus type 1 (HIV-1) transactivating (Tat) protein-enhanced monocyte-like cell adhesion to proteins of the extracellular matrix (ECM).

Main Methods: Collagen IV, laminin, or an ECM gel was used to construct extracellular matrix layers. Human U937 monocyte-like cells were exposed to Tat in the presence of ∆(9)-tetrahydrocannabinol (THC), CP55,940, and other select cannabinoids.

The 12th International Workshops on Opportunistic Protists (IWOP-12).

The 12th International Workshops on Opportunistic Protists (IWOP-12) was held in August 2012 in Tarrytown, New York. The objectives of the IWOP meetings are to: (1) serve as a forum for exchange of new information among active researchers concerning the basic biology, molecular genetics, immunology, biochemistry, pathogenesis, drug development, therapy, and epidemiology of these immunodeficiency-associated pathogenic eukaryotic microorganisms that are seen in patients with AIDS and (2) foster the entry of new and young investigators into these underserved research areas. The IWOP meeting focuses on opportunistic protists, e.

The mitochondrial genome and a 60-kb nuclear DNA segment from Naegleria fowleri, the causative agent of primary amoebic meningoencephalitis.

Naegleria fowleri is a unicellular eukaryote causing primary amoebic meningoencephalitis, a neuropathic disease killing 99% of those infected, usually within 7-14 days. Naegleria fowleri is found globally in regions including the US and Australia. The genome of the related nonpathogenic species Naegleria gruberi has been sequenced, but the genetic basis for N.

Structure and function of a unique pore-forming protein from a pathogenic acanthamoeba.

Human pathogens often produce soluble protein toxins that generate pores inside membranes, resulting in the death of target cells and tissue damage. In pathogenic amoebae, this has been exemplified with amoebapores of the enteric protozoan parasite Entamoeba histolytica. Here we characterize acanthaporin, to our knowledge the first pore-forming toxin to be described from acanthamoebae, which are free-living, bacteria-feeding, unicellular organisms that are opportunistic pathogens of increasing importance and cause severe and often fatal diseases.

Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins.

Naegleria fowleri and Naegleria lovaniensis are closely related free-living amoebae found in the environment. N. fowleri causes primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system, while N.

Highlights and summaries of the 11th International Workshops on Opportunistic Protists.

The 11th in the series of International Workshops on Opportunistic Protists (IWOP-11) was held in August 2010 on the Big Island of Hawaii. These meetings are devoted to agents of infections that cause serious problems in AIDS patients and other individuals with defective immune systems. International Workshops on Opportunistic Protists serves as a forum for exchange of current research information on Pneumocystis, Cryptosporidium and the Microsporidia, Toxoplasma, free-living amoebae, kinetoplastid flagellates and other pathogens that are particularly pathogenic in immunodeficient hosts.

Acanthamoeba culbertsoni elicits soluble factors that exert anti-microglial cell activity.

Acanthamoeba culbertsoni is an opportunistic pathogen that causes granulomatous amoebic encephalitis (GAE), a chronic and often fatal disease of the central nervous system (CNS). A hallmark of GAE is the formation of granulomas around the amoebae. These cellular aggregates consist of microglia, macrophages, lymphocytes, and neutrophils, which produce a myriad of proinflammatory soluble factors.

Identification of Naegleria fowleri in warm ground water aquifers.

The free-living amoeba Naegleria fowleri was identified as the etiological agent of primary amoebic meningoencephalitis that caused the deaths of two children in Peoria, Arizona, in autumn of 2002. It was suspected that the source of N. fowleri was the domestic water supply, which originates from ground water sources.

Free-living amoebae, Legionella and Mycobacterium in tap water supplied by a municipal drinking water utility in the USA.

Legionella and Mycobacterium can proliferate within free-living amoebae (FLA) where they are protected from disinfectants at concentrations that can kill bacteria but not protozoa. Despite effective treatment of drinking water, microbes can enter water utility distribution systems (DS) and hence the plumbing within building premises. Additionally, biofilm formation may account for the persistence of microbes in the DS.

Acanthamoeba culbertsoni: analysis of amoebic adhesion and invasion on extracellular matrix components collagen I and laminin-1.

Acanthamoeba are free-living amoebae found in most environments that can cause brain and corneal infections. To infect humans, these pathogens must interact with host cells and the extracellular matrix (ECM). In order to define the mode by which amoebae recognize ECM components and process this recognition, we analyzed Acanthamoeba culbertsoni attachment and invasion, respectively, on collagen I and laminin-1 and on tridimensional collagen I and matrigel matrices.

Diagnosis of infections caused by pathogenic free-living amoebae.

Naegleria fowleri, Acanthamoeba spp., Balamuthia mandrillaris, and Sappinia sp. are pathogenic free-living amoebae.

Acanthamoeba interaction with extracellular matrix glycoproteins: biological and biochemical characterization and role in cytotoxicity and invasiveness.

Acanthamoeba are free-living amoebae that are dispersed in most environments. Occasionally, Acanthamoeba cause serious human infections, such as keratitis and encephalitis. During the infection process, amoebic adhesion to, and degradation of, host cells and their extracellular matrix (ECM) appear to be important requirements.

Survey for the presence of Naegleria fowleri amebae in lake water used to cool reactors at a nuclear power generating plant.

Water from Lake Anna in Virginia, a lake that is used to cool reactors at a nuclear power plant and for recreational activities, was assessed for the presence of Naegleria fowleri, an ameba that causes primary amebic meningoencephalitis (PAM). This survey was undertaken because it has been reported that thermally enriched water fosters the propagation of N. fowleri and, hence, increases the risk of infection to humans.