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Contributions to microbiology. Bacterial sensing and signaling. Foreword.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19591248 [PubMed - in process]
Source: Contributions to Microbiology - July 15, 2009 Category: Microbiology Authors: Collin M, Schuch R Tags: Contrib Microbiol Source Type: journals

Engineering Bacterial Signals and Sensors.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the emerging field of synthetic biology, a central goal is to reliably engineer bacteria to respond to environmental signals according to a pre-determined genetic program. The sensor systems and genetic circuitry inside bacteria are the 'eyes' and 'brain' of a new class of biotechnological applications in which bacteria are used as living, self-replicating computers that can beneficially interact with the physical world. These engineered gene networks are constructed by extracting natural sensor systems and other genetic parts from multiple organisms and recombining them into novel configurations. This chapter is a ...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Salis H, Tamsir A, Voigt C Tags: Contrib Microbiol Source Type: journals

Magnetosomes and Magneto-Aerotaxis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Magnetotactic bacteria orient and migrate along geomagnetic field lines. Magneto-aerotaxis increases the efficiency of respiring microaerophilic cells to efficiently find and maintain a position at a preferred microaerobic oxygen concentration. Magneto-aerotaxis could also facilitate access to regions of higher nutrient and electron acceptor concentration via periodic excursions above and below the preferred oxygen concentration level. PMID: 19494586 [PubMed - as supplied by publisher]
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Frankel RB, Bazylinski DA Tags: Contrib Microbiol Source Type: journals

Prevailing Concepts of c-di-GMP Signaling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recently, the list of ubiquitous bacterial secondary messengers which include cAMP and ppGpp has been extended by 3',5'-cyclic diguanylic acid (c-di-GMP). C-di-GMP metabolism is tuned by the tightly controlled activity of diguanylate cyclases and c-di-GMP-specific phosphodiesterases. As c-di-GMP-metabolizing enzymes are not only found frequently in bacterial genomes, but also are often numerous in individual genomes, the c-di-GMP metabolic network is highly complex whereby signaling specificity is adjusted on the level of expression, enzymatic activity, protein localization and, most likely, receptor affinity. The targ...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Romling U, Simm R Tags: Contrib Microbiol Source Type: journals

RNA Thermosensors in Bacterial Pathogens.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During the course of an infection, a pathogenic bacterium has to sense the environment and adjust its gene expression appropriately. One such environmental cue is the difference in temperature inside and outside the host. RNA thermosensors are structures that can respond to differences in temperature by altering their conformation and thereby allowing/preventing binding of the ribosome to the translational start site. This chapter discusses different types of RNA thermosensors in general and RNA thermosensors known to control virulence gene expression in particular. PMID: 19494584 [PubMed - as supplied by publisher]
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Johansson J Tags: Contrib Microbiol Source Type: journals

Bacterial Sensing of Antimicrobial Peptides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antimicrobial peptides (AMPs) form a crucial part of human innate host defense, especially in neutrophil phagosomes and on epithelial surfaces. Bacteria have a variety of efficient resistance mechanisms to human AMPs, such as efflux pumps, secreted proteases, and alterations of the bacterial cell surface that are aimed to minimize attraction of the typically cationic AMPs. In addition, bacteria have specific sensors that activate AMP resistance mechanisms when AMPs are present. The prototypical Gram-negative PhoP/PhoQ and the Gram-positive Aps AMP-sensing systems were first described and investigated in Salmonella typh...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Otto M Tags: Contrib Microbiol Source Type: journals

The Heme Sensor System of Staphylococcus aureus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The important human pathogen Staphylococcus aureus is able to satisfy its nutrient iron requirement by acquiring heme from host hemoglobin in the context of infection. However, heme acquisition exposes S. aureus to heme toxicity. In order to detect the presence of toxic levels of exogenous heme, S. aureus is able to sense heme through the heme sensing system (HssRS) two-component system. Upon sensing heme, HssRS directly regulates the expression of the heme-regulated ABC transporter HrtAB, which alleviates heme toxicity. Importantly, the inability to sense or respond to heme alters the virulence of S. aureus, highlight...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Stauff DL, Skaar EP Tags: Contrib Microbiol Source Type: journals

Stand-Alone Response Regulators Controlling Global Virulence Networks in Streptococcus pyogenes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Global regulation of virulence gene expression via transcriptional regulators plays a central role in the ability of the bacterial pathogen Streptococcus pyogenes (the group A Streptococcus, GAS) to rapidly adapt during infection. The 'stand-alone' regulators Mga, RofA-like proteins (RALPs), and RopB/Rgg control important and diverse virulence regulons in response to growth-related signals and other environmental conditions in GAS. Stand-alone regulated genes encode factors important for colonization of tissues, immune evasion, persistence, dissemination, metabolism, and the response to stressors. Although conserved 'c...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: McIver KS Tags: Contrib Microbiol Source Type: journals

Correlations between Carbon Metabolism and Virulence in Bacteria.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bacteria have developed several mechanisms which allow the preferred utilization of the most efficiently metabolizable carbohydrates when these organisms are exposed to a mixture of carbon sources. Interestingly, the same or similar mechanisms are used by some pathogens to control various steps of their infection process. The efficient metabolism of a carbon source might serve as signal for proper fitness. Alternatively, the presence of a specific carbon source might indicate to bacterial cells that they thrive in infection-related organs, tissues or cells and that specific virulence genes should be turned on or switch...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Poncet S, Milohanic E, Mazé A, Abdallah JN, Aké F, Larribe M, Deghmane AE, Taha MK, Dozot M, De Bolle X, Letesson JJ, Deutscher J Tags: Contrib Microbiol Source Type: journals

Bacterial PEP-Dependent Carbohydrate: Phosphotransferase Systems Couple Sensing and Global Control Mechanisms.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The PEP-dependent carbohydrate:phosphotransferase systems (PTSs) of enteric bacteria constitute a complex sensory system which involves as its central element a PEP-dependent His-protein kinase (Enzyme I). As a unit, the PTS comprises up to 20 different transporters per cell which correspond to its chemoreceptors for PTS carbohydrates, and several targeting subunits, which include in the low [G + C] Gram-positive bacteria an ancillary Ser/Thr-protein kinase. The PTS senses the presence of carbohydrates, in particular glucose, in the medium and the energy state of the cell, in the form of either the intracellular PEP-to...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Lengeler JW, Jahreis K Tags: Contrib Microbiol Source Type: journals

The Molecular Basis of Excitation and Adaptation during Chemotactic Sensory Transduction in Bacteria.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chemotaxis is the process by which cells sense chemical gradients in their environment and then move towards more favorable conditions. In the case of Escherichia coli, the paradigm organism for chemotaxis, the pathway is now arguably the best characterized in all of biology. If one broadenstheir perspective to include other species of bacteria, then our knowledge of chemotaxis is far less developed. In particular, the chemotaxis pathways in unrelated species are quite different despite the conservation of many core signaling proteins. Here, we summarize the current state of knowledge regarding the chemotaxis pathways ...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Rao CV, Ordal GW Tags: Contrib Microbiol Source Type: journals

Autoinducer-2-Based Chemical Communication in Bacteria: Complexities of Interspecies Signaling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell-cell communication in bacteria, called quorum sensing, relies on production, release, and detection of signaling molecules, termed autoinducers. Communication enables populations of cells to synchronize gene expression and therefore behave as a group in a manner akin to cells in multicellular organisms. Most quorum-sensing systems allow communication within an individual species of bacteria. However, one autoinducer, called AI-2, is produced and recognized by many different bacterial species, indicating that some bacteria communicate across species boundaries. Current studies are aimed at discovering the role that...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Federle MJ Tags: Contrib Microbiol Source Type: journals

Chemical Interactions between Organisms in Microbial Communities.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bacteria live almost exclusively in communities with other microorganisms, and often in association with multicellular hosts. These communities are capable of maintaining complex structural and functional stability over time, and exhibit fascinating properties of resiliency in response to environmental changes. This is a result of interactions between microbes and the environment and amongst members of the community. A multitude of chemical interactions occur in microbial communities where primary and secondary metabolites contribute to a wealth of interactions between organisms. The chemicals include a variety of nutr...
Source: Contributions to Microbiology - June 13, 2009 Category: Microbiology Authors: Duan K, Sibley CD, Davidson CJ, Surette MG Tags: Contrib Microbiol Source Type: journals

Aging and impairment of innate immunity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
As we age, it is common for certain phenotypic changes to arise within the population. A number of observations have led scientists to believe that these changes result from an accumulation of cellular defects over time. With enough cell damage, tissue function is compromised and the risk for disease escalates. More importantly, when these defects arise in cells of the innate immune system, the body can no longer defend itself against a variety of pathologies. The main culprit for cellular damage seen with age is thought to be reactive oxygen and nitrogen species produced from endogenous metabolic pathways. To determin...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Nomellini V, Gomez CR, Kovacs EJ Tags: Contrib Microbiol Source Type: journals

Oxidative innate immune defenses by Nox/Duox family NADPH oxidases.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The importance of reactive oxygen species (ROS) in innate immunity was first recognized in professional phagocytes undergoing a 'respiratory burst'upon activation. This robust oxygen consumption is related to a superoxide-generating enzyme, the phagocytic NADPH oxidase (Nox2-based or phox). The oxidase is essential for microbial killing, since patients lacking a functional oxidase suffer from enhanced susceptibility to microbial infections. ROS derived from superoxide attack bacteria in the isolated niche of the neutrophil phagosome. The oxidase is electrogenic, alters ion currents across membranes, induces apoptosis, ...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Rada B, Leto TL Tags: Contrib Microbiol Source Type: journals

Innate immune functions of the airway epithelium.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The epithelium of the respiratory tract forms a large surface area that maintains intimate contact with the environment. Through the act of breathing, this mucosal surface encounters an array of pathogens and toxic particulates. In response to these challenges many strategies have evolved to protect the host. These include the barrier functions of the epithelium, cough, mucociliary clearance, resident professional phagocytes, and the secretion of a number of proteins and peptides with host defense functions. Thus, the surface and submucosal gland epithelium of the conducting airways is a constitutive primary participan...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Bartlett JA, Fischer AJ, McCray PB Tags: Contrib Microbiol Source Type: journals

The role of neutrophils and monocytes in innate immunity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Polymorphonuclear neutrophils (PMNs) and monocyte/macrophages (MMs) are professional phagocytic cells that are able to phagocytose and destroy infectious agents. Therefore, they are key anti-infectious actors in host defense but can mediate tissue damages. In addition, it is now clear that the role of these cells goes far beyond phagocytosis and pathogen killing. PMNs and MMs are essential cells for immunity, absolutely required to build and modulate the innate response. The respective roles of PMNs and MMs in the inflammatory process are discussed: their common features and their differences are reviewed, both in term...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Kantari C, Pederzoli-Ribeil M, Witko-Sarsat V Tags: Contrib Microbiol Source Type: journals

Antibacterial chemokines--actors in both innate and adaptive immunity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Several antibacterial proteins and peptides of the human innate immune system have additional roles in the regulation of adaptive immune responses. Among peptides with innate and adaptive immune functions are chemokines, a family of structurally related peptides with conserved amino-terminal motifs. Chemokines regulate leukocyte trafficking during both health and disease. In recent years, some chemokines have been shown to exert direct antibacterial activity. On the other hand, several granulebound antibacterial proteins of granulocytes, and epithelium-expressed antibacterial polypeptides, possess chemotactic activity ...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Eliasson M, Egesten A Tags: Contrib Microbiol Source Type: journals

Complement: an efficient sword of innate immunity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Complement is vital for protecting individuals against pathogens and any disturbance of homeostasis associated with appearance of foreign antigens. Four antenna molecules seek for putative danger and subsequently start three activation pathways to eliminate the hostile triggering signal. To achieve this mission the complement arsenal contains soluble plasma factors as well as membrane-bound receptor molecules. Fulfilling a broad spectrum of biological functions, complement participates to construct and orchestrate an immunological network with extensive links to other elements of innate immunity, but also to its younge...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Rambach G, Würzner R, Speth C Tags: Contrib Microbiol Source Type: journals

Antimicrobial peptides in innate immune responses.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain diseases like Crohn's disease...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Sørensen OE, Borregaard N, Cole AM Tags: Contrib Microbiol Source Type: journals

Pattern recognition receptors and their role in innate immunity: focus on microbial protein ligands.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antigen-presenting cells, such as macrophages and dendritic cells, represent a central and important part of the immune defence against invading microorganisms, as they participate in initial capture and processing of microbial antigens (innate immunity) and then activation of specific T and B cell effector mechanisms (acquired immunity). Recognition of microbial molecules by antigen-presenting cells occurs through so called pattern recognition receptors (PRRs), which recognize conserved structures, or pathogen-associated molecular patterns, in pathogenic microbes. The Toll-like receptors are the most extensively studi...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Areschoug T, Gordon S Tags: Contrib Microbiol Source Type: journals

The innate immune system of mammals and insects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Infectious agents threaten any organism. Therefore, mammals and insects have evolved a complex network of cells and humoral factors termed immune system able to control and eliminate pathogens. Immunity varies between different groups of animals but always contains an innate immune system that can act fast and often effectively against a wide range of distinct pathogens (i.e. viruses, bacteria, fungi, and eukaryotic parasites). In mammals and insects, the communication between and regulation of immune cells is carried out by cytokines which orchestrate the defense against the invaders. The major challenge to recognize ...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Müller U, Vogel P, Alber G, Schaub GA Tags: Contrib Microbiol Source Type: journals

General introduction to innate immunity: Dr. Jekyl/Mr. Hyde quality of the innate immune system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The innate immunity plays a critical role in host protection against pathogens and transformed cells. It relies amongst others on pattern recognition receptors such as Toll-like receptors, C-type lectin receptors, and nucleotide-binding oligomerization domain proteins to alert and activate defense pathways including the activation of the complement system. Innate immunity represents a trait common to plants and animals, and besides the humoral factors different cell types e.g. subspecies of dendritic cells (plasmacytoid dendritic cells), phagocytic cells, mast cells, glia cells, Kupffer cells, neutrophils and natural k...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Zänker KS Tags: Contrib Microbiol Source Type: journals

From Darwin and Metchnikoff to Burnet and beyond.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Phagocytosis in unicellular animals represents the most ancient and ubiquitous form of defense against foreign material. Unicellular invertebrates can phagocytose for food and defense. Multicellular invertebrates and vertebrates possess phagocytic cells and have evolved more complex functions attributed to immunodefense cells that specialized into cellular and humoral immune responses. Thus all animals possess: innate, natural, nonspecific (no memory) nonanticipatory, nonclonal, germline (hard wired) host defense functions. In addition, all vertebrates possess: adaptive, induced, specific (memory), anticipatory, clonal...
Source: Contributions to Microbiology - September 24, 2008 Category: Microbiology Authors: Cooper EL Tags: Contrib Microbiol Source Type: journals

Animal models of chronic obstructive pulmonary disease exacerbations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Modeling acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in animals has proven challenging due to the clinical and pathological complexity of the underlying disease. This has hindered the progress in understanding the cellular and molecular mechanisms that lie beneath AECOPD. In this chapter, we will address modeling possibilities of AECOPD that may be drawn from the current knowledge of factors that cause exacerbations. Importantly, since it is widely accepted that the most common causes of AECOPD are viral and bacterial infections, animal models of AECOPD should incorporate both the causative ag...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Gaschler GJ, Bauer CM, Zavitz CC, Stämpfli MR Tags: Contrib Microbiol Source Type: journals

Animal models of cigarette smoke-induced chronic obstructive lung disease.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recent years have seen an explosion of animal models of cigarette smoke-induced chronic obstructive lung disease (COPD). Almost all of these have concentrated on the induction and prevention of emphysema. Neutrophils and neutrophil elastase, macrophages and macrophage-derived metalloproteases, lymphocytes, TNF-alpha, and oxidants have all been shown to play a role in the pathogenesis of emphysema in animal models, and interventions using either knockout mice or drugs have indicated possible preventive/therapeutic avenues. There is less in the way of models of smoke-induced small airway remodeling and almost nothing is ...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Churg A, Wright JL Tags: Contrib Microbiol Source Type: journals

A human rhinovirus model of chronic obstructive pulmonary disease exacerbations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chronic obstructive pulmonary disease (COPD) exacerbations are common events that punctuate the natural history of COPD contributing to disease severity progression and being the major cause of COPD-related morbidity and mortality. Currently available pharmacological strategies are only partially effective at reducing or preventing COPD exacerbations. Viral infections are the most frequent cause of COPD exacerbations. The recent development of a human experimental model of rhinovirus-induced COPD exacerbations represents an innovative tool with the potential to increase our understanding of the inflammatory and immunol...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Contoli M, Caramori G, Mallia P, Papi A, Johnston SL Tags: Contrib Microbiol Source Type: journals

Lipopolysaccharide challenge of humans as a model for chronic obstructive lung disease exacerbations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Endotoxin, or lipopolysaccharide (LPS), is a constituent of the outer cell membrane of Gram-negative bacteria. LPS is a highly potent proinflammatory substance, that, when inhaled, dose-dependently causes fever, chills, and bronchoconstriction. These symptoms are accompanied by a proinflammatory response in sputum and bronchoalveolar lavage fluid with elevation of neutrophils, macrophages and certain cytokines/chemokines. This response can be partially modified with certain drugs. Similar inflammatory changes are observed both in the stable state of chronic obstructive lung disease (COPD) and during exacerbations of th...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Kharitonov SA, Sjöbring U Tags: Contrib Microbiol Source Type: journals

Respiratory syncytial virus-induced pulmonary disease and exacerbation of allergic asthma.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Several respiratory viruses have been shown to cause exacerbations of asthma. While the various viral responses likely have common mechanisms of activation, the respiratory syncytial virus (RSV) appears to promote specific responses that on their own can cause severe pulmonary problems. Understanding the mechanisms that promote inappropriate immune responses and local damage may lead to better therapy. The activation and recruitment of T cells that amplify and skew the immune response toward more intense pathology, including mucus production and remodeling of the airways, are likely scenarios that lead to more severe d...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Lukacs NW, Smit J, Lindell D, Schaller M Tags: Contrib Microbiol Source Type: journals

Modeling responses to respiratory house dust mite exposure.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
House dust mite (HDM) is the most pervasive indoor aeroallergen source worldwide. Allergens derived from HDM are associated with sensitization and allergic asthma. Allergic asthma is an immunologically driven disease characterized by a Th2-polarized immune response, eosinophilic inflammation, airway hyperreactivity, and remodeling. Animal models of asthma utilizing ovalbumin (OVA) exposure have afforded us considerable insight with respect to the mediators and cell types involved in allergic airway inflammation. However, OVA preparations and HDM are two vastly different materials. This chapter is specifically concerned...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Cates EC, Fattouh R, Johnson JR, Llop-Guevara A, Jordana M Tags: Contrib Microbiol Source Type: journals

Cellular and animals models for rhinovirus infection in asthma.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Human rhinoviruses (RVs) are responsible for the majority of upper respiratory tract infections. Despite the high prevalence, the pathogenesis is incompletely understood. Experimental models would permit study of the immunological response to infections. Animal models have many limitations because of the anatomic and physiological differences between mammalian species. The only nonhuman animals susceptible to RV are chimpanzees and gibbons. Mouse models are not used because of host cell tropism of RV. This problem may have been partially overcome by transfecting mouse cells with viral RNA, by replacing mouse ICAM-1 wit...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Xatzipsalti M, Papadopoulos NG Tags: Contrib Microbiol Source Type: journals

Allergen inhalation challenge: a human model of asthma exacerbation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Allergen challenge by inhalation is a very useful clinical and research tool for evaluating allergic airway disease. Inhalation of allergen leads to cross-linking of allergen-specific IgE bound to IgE receptors on mast cells and basophils. This is followed by activation of secretory pathways to release preformed and newly generated mediators of bronchoconstriction and vascular permeability. The onset of bronchoconstriction, representing the early phase of the asthmatic response, can be detected within 10 min of the inhalation, reaches a maximum within 30 min, and resolves within 3 h. The late-phase asthmatic response s...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Gauvreau GM, Evans MY Tags: Contrib Microbiol Source Type: journals

Human rhinovirus models in asthma.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In both children and adults, rhinovirus (RV) infections remain a major cause of exacerbations in asthma. With the use of both in vitro models of RV infection and experimental models of asthma exacerbation in humans, insight into the precise role of RV in this process has been obtained. RV infects the lower airways, and the virus itself, together with the immune response to the virus, leads to increased airway obstruction in some patients with asthma. Defects in the immune response to RV in these patients may also lead to increased symptom severity and to more significant exacerbations. Work further investigating the me...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: Singh AM, Busse WW Tags: Contrib Microbiol Source Type: journals

Exacerbations of asthma and COPD: definitions, clinical manifestations and epidemiology.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Exacerbations are important events in patients with asthma and chronic obstructive pulmonary disease (COPD). Reducing the number, frequency and the severity of exacerbations is therefore an important management goal identified by treatment guidelines for both diseases. There are similarities with respect to clinical manifestations, etiology and epidemiology, but there are also clear differences not the least in how well patients respond to treatment. The similarities and differences between exacerbations asthma and COPD with an emphasis on epidemiology and clinical presentation are discussed and compared in this chapte...
Source: Contributions to Microbiology - January 1, 2007 Category: Microbiology Authors: O'Byrne PM Tags: Contrib Microbiol Source Type: journals

Infection, inflammation and neoplasia: an interdisciplinary challenge.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During the past two to three decades there has been an exciting revolution in our understanding of the multistage carcinogenic process and of the molecular genetics of cancer. The general principle of multifactor interactions is central to our understanding of cancer causation. The paradigm that persistent infections and chronic inflammation contributes via cytokine- and chemokine-mediated disbalanced immune response to carcinogenesis becomes more and more attractive in cancer research. Besides genetic factors, the epigenetics of impaired cell signaling and signal transduction by proinflammatory cytokines and chemokine...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Zaenker KS Tags: Contrib Microbiol Source Type: journals

Options for visualizing metastatic disease in the living body.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective is to provide the cancer researcher with information that will help solve the dilemma of how best to apply the latest imaging tools for studying biological questions in the context of the living body. PMID: 16627968 [PubMed - indexed for MEDLINE]
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Helms MW, Brandt BH, Contag CH Tags: Contrib Microbiol Source Type: journals

Visualization of tumor cell extravasation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In cancer the blood-borne spread of tumor cells leads to the formation of secondary tumors at distant loci, whereby the extravasation of tumor cells is a prerequisite step during hematogenous metastasis. In regard to the fate of endothelial cells located at the site of tumor cell infiltration, tumor cell-endothelial interactions were analyzed using an in vitro real-time model. This model shows the complete sequence of the transmigration process and gave new insights into the complex and dynamic cell-cell and cell-matrix interactions which occur during tumor cell transmigration across the endothelial barrier. An in vitr...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Heyder C, Gloria-Maercker E, Hatzmann W, Zaenker KS, Dittmar T Tags: Contrib Microbiol Source Type: journals

Involvement of chemokine receptors in organ-specific metastasis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The chemokines are a family of small proteins known for their ability to control cell migration in the body. Their receptors belong to the class A subfamily of G protein-coupled receptors. In recent years, chemokines have grown in importance, because they are involved in inflammation and autoimmune disease. Some of them are also involved in infectious disease, since two chemokine receptors, CXCR4 and CCR5, are used by the human immunodeficiency virus (HIV) to gain entry to cells. Several years ago it also became clear that chemokines can also influence tumor cells. Specifically, tumor cells express chemokine receptors ...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Zlotnik A Tags: Contrib Microbiol Source Type: journals

Chemokine-directed metastasis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Over the last 20 years, the biology of chemokines has expanded beyond their initial role in mediating migration of specific subsets of leukocytes. Chemokines have been found to display pleiotropic effects for enhancing immunity to tumor-associated antigens, regulating angiogenesis, promoting proliferation/anti-apoptosis of tumor cells; and mediating tumor cell invasion and trafficking in an organ-specific manner that leads to metastases. Here, we review the importance of chemokines, especially CXC chemokines in regulating angiogenesis, tumor cell invasion and metastases; and demonstrate why they can be seen as importan...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Gomperts BN, Strieter RM Tags: Contrib Microbiol Source Type: journals

Carcinogenesis driven by bone marrow-derived stem cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The overall mechanism of bone marrow-derived stem cell (BMDC) trans-differentiation seems to be simple: BMDCs trans-differentiate as referred to the blueprint, which is given by the tissue itself. Thereby, the blueprint can be the local tissue micro-environment (defined by the tissue-specific cytokine, chemokine, adhesion molecule pattern, etc.), it can be a single cell (cell fusion), or it can be a combination of both. In fact stem cell trans-differentiation is a complex not yet fully understood process. In between the start- and stop-points of transdifferentiation several gene reprogramming steps have to occur in a s...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Dittmar T, Seidel J, Zaenker KS, Niggemann B Tags: Contrib Microbiol Source Type: journals

Co-opting macrophage traits in cancer progression: a consequence of tumor cell fusion?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tumor-associated macrophages (TAMs) play multiple roles in tumor initiation and progression. Tumors frequently appear in areas of chronic inflammation. This is likely aided by the mutagenic actions of macrophages. Tumor growth and progression is supported by macrophage-induced neoangiogenesis and stroma production, and macrophages produce tumor-stimulating growth factors. In most cancers a high density of TAMs predicts poor outcome. But not only do cancer cells depend upon macrophages for growth and invasion, they also co-opt macrophage traits. These include a wide diversity of molecules and pathways regulating adhesio...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Pawelek J, Chakraborty A, Lazova R, Yilmaz Y, Cooper D, Brash D, Handerson T Tags: Contrib Microbiol Source Type: journals

The inflammatory tumor microenvironment and its impact on cancer development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The role of the immune system during cancer development is complex involving extensive reciprocal interactions between genetically altered cells, adaptive and innate immune cells, their soluble mediators and structural components present in the neoplastic microenvironment. Each stage of cancer development is regulated uniquely by the immune system; whereas full activation of adaptive immune cells at the tumor stage may result in eradication of malignant cells, chronic activation of innate immune cells at sites of premalignant growth may actually enhance tumor development. In addition, the balance between desirable anti...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: de Visser KE, Coussens LM Tags: Contrib Microbiol Source Type: journals

Relevant oncogenic viruses in veterinary medicine: original pathogens and animal models for human disease.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Oncogenic viruses are important pathogens in farm and companion animals. These original pathogens are classified in various virus families, such as Retroviridae, Papillomaviridae, and Herpesviridae. Besides a role as pathogens for its original host, animal viruses serve as valuable models for viruses affecting humans, such as hepatitis B virus, and issues of immunity, therapy, but also basic pathophysiological mechanisms, can often only be addressed in those animal systems. PMID: 16627961 [PubMed - indexed for MEDLINE]
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Truyen U, Löchelt M Tags: Contrib Microbiol Source Type: journals

Schistosomiasis and neoplasia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Schistosomiasis is endemic in at least 75 tropical and subtropical countries where 600 million people are at risk of which over 200 million are infected. Three species, S. hematobium, S. mansoni and S. japonicum, account for the majority of human infections. There is sufficient evidence that S. hematobium, the predominant etiologic agent for urinary schistosomiasis, is carcinogenic to humans leading to squamous cell carcinoma of the urinary bladder, a relatively uncommon vesical cancer in nonendemic areas. There is limited evidence suggesting that S. japonicum is possibly carcinogenic to humans leading to colorectal ca...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Yosry A Tags: Contrib Microbiol Source Type: journals

Helicobacter pylori and gastric neoplasia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Helicobacter pylori is present in the stomach of more than half of the world population. Based on compelling epidemiological evidences, it was classified by the World Health Organization as a type I gastric carcinogen. It is generally believed that gastric cancer development is a multi-step progression from chronic gastritis to atrophy, intestinal metaplasia, dysplasia, and cancer. Individuals infected with H. pylori have at least a 2-fold increase in risk of gastric cancer development though only a small proportion of infected individuals will ultimately develop this malignancy. The exact mechanisms underlying how H. ...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Leung WK Tags: Contrib Microbiol Source Type: journals

Adult stem cell theory of the multi-stage, multi-mechanism theory of carcinogenesis: role of inflammation on the promotion of initiated stem cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Inflammation, induced by microbial agents, radiation, endogenous or exogenous chemicals, has been associated with chronic diseases, including cancer. Since carcinogenesis has been characterized as consisting of the 'initiation', 'promotion' and 'progression' phases, the inflammatory process could affect any or all three phases. The stem cell theory of carcinogenesis has been given a revival, in that isolated human adult stem cells have been isolated and shown to be 'targets' for neoplastic transformation. Oct4, a transcription factor, has been associated with adult stem cells, as well as their immortalized and tumorige...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Trosko JE, Tai MH Tags: Contrib Microbiol Source Type: journals

Aneuploidy and cancer: from correlation to causation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conventional genetic theories have failed to explain why cancer (1) is not found in newborns and thus not heritable; (2) develops only years to decades after 'initiation' by carcinogens; (3) is caused by non-mutagenic carcinogens; (4) is chromosomally and phenotypically 'unstable'; (5) carries cancer-specific aneuploidies; (6) evolves polygenic phenotypes; (7) nonselective phenotypes such as multidrug resistance, metastasis or affinity for non-native sites and 'immortality' that is not necessary for tumorigenesis; (8) contains no carcinogenic mutations. We propose instead that cancer is a chromosomal disease: According...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Duesberg P, Li R, Fabarius A, Hehlmann R Tags: Contrib Microbiol Source Type: journals

In memoriam of Rudolf virchow: a historical retrospective including aspects of inflammation, infection and neoplasia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Rudolf Ludwig Carl Virchow (1821-1902) studied medicine and received his academic degree 'Dr. med.' in 1843. In 1856 he was appointed as head of the institute of pathology at the University of Berlin. In 1859, he became a member of the Berlin town council and later additionally a member of the Prussian and the German parliament. With his probably most important publication 'Cellularpathologie' he introduced pathology to a cellular rationale. This was the major basis for his research in oncology. Virchow further studied aspects of inflammation, despite only few links to tumor pathology were drawn. The few links from inf...
Source: Contributions to Microbiology - January 1, 2006 Category: Microbiology Authors: Schmidt A, Weber OF Tags: Contrib Microbiol Source Type: journals

Horizontal and vertical gene transfer: the life history of pathogens.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 15496784 [PubMed - indexed for MEDLINE]
Source: Contributions to Microbiology - January 1, 2005 Category: Microbiology Authors: Lawrence JG Tags: Contrib Microbiol Source Type: journals

Pathogenicity islands and their role in bacterial virulence and survival.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 15496783 [PubMed - indexed for MEDLINE]
Source: Contributions to Microbiology - January 1, 2005 Category: Microbiology Authors: Hochhut B, Dobrindt U, Hacker J Tags: Contrib Microbiol Source Type: journals