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Pathogen and Toxin Entry - How Pathogens and Toxins Induce and Harness Endocytotic Mechanisms (Book chapter)

Book title: Molecular Regulation of Endocytosis

Authors: --- ---
ISBN: 9789535106623 Year: DOI: 10.5772/45946 Language: English
Publisher: IntechOpen Grant: FP7 Ideas: European Research Council - 282105
Subject: Science (General)
Added to DOAB on : 2019-01-17 11:47:59
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Humans have been exposed to a plethora of pathogens (bacteria, viruses) ever since. Infectious diseases are among the leading causes of death worldwide. For example, in 2011, 1.34 million people died of tuberculosis, which is caused by an infection with Mycobacterium tuberculosis. Even more died of an infection by the human immunodeficiency virus (HIV; 1.78 million) or lower respiratory tract infection (3.46 million) [1]. In addition, recurring pandemic outbreaks of the influenza A virus, as in 2009, or an epidemic outbreak of enterohemorrhagic E. coli (EHEC) in Germany in 2011, show quite plainly that pathogens in the 21th century still are a severe health problem, not only in developing countries.

Keywords

toxin --- pathogen

Ribosome Inactivating Toxins

Authors: ---
ISBN: 9783038972488 9783038972495 Year: Pages: 329 DOI: 10.3390/books978-3-03897-249-5 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Therapeutics --- Public Health
Added to DOAB on : 2019-01-17 10:21:23
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Ribosome inactivating proteins (RIPs) form a vast family of hundreds of toxins from plants, fungi, algae and bacteria. RIP activities have also been detected in animal tissues. They target a single adenine of a ribosomal RNA, thereby blocking protein synthesis and leading intoxicated cells to apoptosis. The role of plant RIPs may be related to plant defense against predators and viruses, plant senescence or bacterial pathogenesis. Most RIPs are no threat to human or animal health. However, several bacterial RIPs are major virulence factors involved in severe epidemic diseases such as dysentery or the hemolytic uremic syndrome that may occur in patients suffering from Shiga toxin-producing entero-hemorrhagic Escherichia coli infection. Several plant RIPs such as ricin toxin, abrin or sarcin have been, or may be involved in accidental or criminal poisonings, political intimidation or bio-suicides. Health crisis, biosafety and biosecurity issues became a major concern and many efforts are made to develop treatments. Finally, RIPs can be engineered into immunotoxins to destroy cancer cells or cells chronically infected by viruses.This book presents the most recent data on all aspects of RIPs including function, diversity and evolution, mechanism, pathophysiology, medical countermeasures and engineering into anticancer drugs.

Cellular Entry of Binary and Pore-Forming Bacterial Toxins

Author:
ISBN: 9783038427049 9783038427032 Year: Pages: 128 DOI: 10.3390/books978-3-03842-703-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology
Added to DOAB on : 2018-02-08 13:26:54
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Bridging cellular membranes is a key step in the pathogenic action of both binary and pore-forming bacterial toxins. The former use their translocation domains, containing various structural motifs, to ensure efficient delivery of the toxic component into the host cell, while the latter act on the cellular membrane itself. In either case, the integrity of the membrane is compromised via targeted protein–lipid and protein–protein interactions triggered by specific signals, such as proteolytic cleavage or endosomal acidification.This Special Issue presents recent advances in characterizing functional, structural and thermodynamic aspects of the conformational switching and membrane interactions involved in the cellular entry of bacterial protein toxins. Deciphering the physicochemical principles underlying these processes is also a prerequisite for the use of protein engineering to develop toxin-based molecular vehicles capable of targeted delivery of therapeutic agents to tumors and other diseased tissues.

The Insecticidal Bacterial Toxins in Modern Agriculture

Authors: ---
ISBN: 9783038426622 9783038426639 Year: Pages: 162 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology
Added to DOAB on : 2018-01-16 09:46:13
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Increased awareness about environmental adverse effects of human activities has prompted the use of insecticides with low impact on systems associated to agriculture. Currently, the most successful biological products are based on protein toxins from the bacterial species Bacillus thuringiensis. Because of the remarkable properties of these proteins, their encoding genes were introduced into farming species (the so called Bt-crops), in such a way, that these plants are self-protected against some key insect pests. Despite the fact that a relatively large number of these toxins, with different toxicity ranges, have been described, it is still important to find new resources with novel capabilities to complement, or to replace in the future, the currently used ones. On another hand, it is important to continue studying their mode action in susceptible insects, and the changes occurred in resistant ones, to determine the most effective strategy for long lasting pest control. The focus of this Special Issue of Toxins is to provide updated information on the use of B. thuringiensis and their toxins on different field crops, the interactions of these toxins with other molecules, analyze the biochemical and molecular basis of emerging cases of resistance and, in general, to provide information which can contribute to an effective pest management with these toxins.

Emerging Approaches for Typing, Detection, Characterization, and Traceback of Escherichia coli

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451357 Year: Pages: 170 DOI: 10.3389/978-2-88945-135-7 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Pathogenic Escherichia coli strains cause a large number of diseases in humans, including diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, urinary tract infections, and neonatal meningitis, while in animals they cause diseases such as calf scours and mastitis in cattle, post-weaning diarrhea and edema disease in pigs, and peritonitis and airsacculitis in chickens. The different E. coli pathotypes are characterized by the presence of specific sets of virulence-related genes. Therefore, it is not surprising that pathogenic E. coli constitutes a genetically heterogeneous family of bacteria, and they are continuing to evolve. Rapid and accurate molecular methods are critically needed to detect and trace pathogenic E. coli in food and animals. They are also needed for epidemiological investigations to enhance food safety, as well as animal and human health and to minimize the size and geographical extent of outbreaks. The serotype of E. coli strains has traditionally been determined using antisera raised against the >180 different O- (somatic) and 53 H- (flagellar) antigens. However, there are many problems associated with serotyping, including: it is labor-intensive and time consuming; cross reactivity of the antisera with different serogroups occurs; antisera are available only in specialized laboratories; and many strains are non-typeable. Molecular serotyping targeting O-group-specific genes within the E. coli O-antigen gene clusters and genes that are involved in encoding for the different flagellar types offers an improved approach for determining the E. coli O- and H-groups. Furthermore, molecular serotyping can be coupled with determination of specific sets of virulence genes carried by the strain offering the possibility to determine O-group, pathotype, and the pathogenic potential simultaneously. Sequencing of the O-antigen gene clusters of all of the known O-groups of E. coli is now complete, and the sequences have been deposited in the GenBank database. The sequence information has revealed that some E. coli serogroups have identical sequences while others have point mutations or insertion sequences and type as different serogroups in serological reactions. There are also a number of other ambiguities in serotyping that need to be resolved. Furthermore, new E. coli O-groups are being identified. Therefore, there is an essential need to resolve these issues and to revise the E. coli serotype nomenclature based on these findings. There are emerging technologies that can potentially be applied for molecular serotyping and detection and characterization of E. coli. On a related topic, the genome sequence of thousands of E. coli strains have been deposited in GenBank, and this information is revealing unique markers such as CRISPR (clustered regularly interspaced short palindromic repeats) and virulence gene markers that could be used to identify E. coli pathotypes. Whole genome sequencing now provides the opportunity to study the role of horizontal gene transfer in the evolution and emergence of pathogenic E. coli strains. Whole genome sequencing approaches are being investigated for genotyping and outbreak investigation for regulatory and public health needs; however, there is a need for establishing bioinformatics pipelines able to handle large amounts of data as we move toward the use of genetic approaches for non-culture-based detection and characterization of E. coli and for outbreak investigations.

Emerging Approaches for Typing, Detection, Characterization, and Traceback of Escherichia coli, 2nd Edition

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454334 Year: Pages: 172 DOI: 10.3389/978-2-88945-433-4 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2018-11-16 17:17:57
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Pathogenic Escherichia coli strains cause a large number of diseases in humans, including diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, urinary tract infections, and neonatal meningitis, while in animals they cause diseases such as calf scours and mastitis in cattle, post-weaning diarrhea and edema disease in pigs, and peritonitis and airsacculitis in chickens. The different E. coli pathotypes are characterized by the presence of specific sets of virulence-related genes. Therefore, it is not surprising that pathogenic E. coli constitutes a genetically heterogeneous family of bacteria, and they are continuing to evolve. Rapid and accurate molecular methods are critically needed to detect and trace pathogenic E. coli in food and animals. They are also needed for epidemiological investigations to enhance food safety, as well as animal and human health and to minimize the size and geographical extent of outbreaks. The serotype of E. coli strains has traditionally been determined using antisera raised against the >180 different O- (somatic) and 53 H- (flagellar) antigens. However, there are many problems associated with serotyping, including: it is labor-intensive and time consuming; cross reactivity of the antisera with different serogroups occurs; antisera are available only in specialized laboratories; and many strains are non-typeable. Molecular serotyping targeting O-group-specific genes within the E. coli O-antigen gene clusters and genes that are involved in encoding for the different flagellar types offers an improved approach for determining the E. coliO- and H-groups. Furthermore, molecular serotyping can be coupled with determination of specific sets of virulence genes carried by the strain offering the possibility to determine O-group, pathotype, and the pathogenic potential simultaneously. Sequencing of the O-antigen gene clusters of all of the known O-groups of E. coli is now complete, and the sequences have been deposited in the GenBank database. The sequence information has revealed that some E. coli serogroups have identical sequences while others have point mutations or insertion sequences and type as different serogroups in serological reactions. There are also a number of other ambiguities in serotyping that need to be resolved. Furthermore, new E. coli O-groups are being identified. Therefore, there is an essential need to resolve these issues and to revise the E. coli serotype nomenclature based on these findings. There are emerging technologies that can potentially be applied for molecular serotyping and detection and characterization of E. coli. On a related topic, the genome sequence of thousands of E. coli strains have been deposited in GenBank, and this information is revealing unique markers such as CRISPR (clustered regularly interspaced short palindromic repeats) and virulence gene markers that could be used to identify E. coli pathotypes. Whole genome sequencing now provides the opportunity to study the role of horizontal gene transfer in the evolution and emergence of pathogenic E. coli strains. Whole genome sequencing approaches are being investigated for genotyping and outbreak investigation for regulatory and public health needs; however, there is a need for establishing bioinformatics pipelines able to handle large amounts of data as we move toward the use of genetic approaches for non-culture-based detection and characterization of E. coli and for outbreak investigations.

Staphylococcus aureus Toxins

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ISBN: 9783039214259 9783039214266 Year: Pages: 204 DOI: 10.3390/books978-3-03921-426-6 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Microbiology
Added to DOAB on : 2019-12-09 11:49:15
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Staphylococcus aureus is a common inhabitant of the human body with which we co-exist. However, this species can also cause disease in humans when an appropriate opportunity arises, such as a cut or some other breakdown in our body’s defenses. S. aureus is able to initiate infections due, in part, to the diverse group of toxins that they secrete. The exotoxins produced by S. aureus can cause direct damage, thwart our own body’s defenses, or trigger massive amounts of cytokines that lead to indirect damage within the human body. In this book are 12 research articles that deal with different aspects of staphylococcal exotoxins. Some of the work gives an overview about how the toxins contribute to the disease process. Other articles discuss different aspects of several exotoxins, and two articles are centered on countermeasures against S. aureus infections. Overall, this book will give the reader a good overview of how staphylococcal exotoxins contribute to initiating and sustaining infections in humans.

Novel Pharmacological Inhibitors for Bacterial Protein Toxins

Author:
ISBN: 9783038424314 9783038424307 Year: Pages: VI, 118 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Public Health --- Biology
Added to DOAB on : 2017-06-13 09:39:34
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Many medically relevant bacteria cause severe human and animal diseases because they produce and release protein toxins that target mammalian cells. Because the toxin-induced cell damage is the reason for the clinical symptoms, the targeted pharmacological inhibition of the cytotoxic mode of action of bacterial toxins should prevent or cure the respective toxin-associated disease. Toxin inhibitors might be beneficial when the toxin acts in the absence of the producing bacteria (e.g., food poisoning), but also in combination with antibiotics in infectious diseases when the toxin-producing bacteria are present. The focus of this Special Issue of Toxins is on the development and characterization of novel inhibitors against bacterial toxins, e.g., toxin neutralizing antibodies, peptides or small compounds, as well as toxin pore blockers, which interfere with bacterial toxins and thereby protect cells from intoxication.

Marine Biotoxins and Seafood Poisoning

Authors: --- ---
ISBN: 9783039218189 9783039218196 Year: Pages: 114 DOI: 10.3390/books978-3-03921-819-6 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Public Health
Added to DOAB on : 2019-12-09 11:49:16
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Marine biotoxins may pose a threat to the human consumption of seafood and seafood products. The increasing global trade and higher demand for seafood products worldwide represents a challenge for food safety authorities, policy makers, food business operators, and the scientific community, in particular, researchers devoted to environmental sciences, toxicology, and analytical chemistry. In addition, due to changes in climate conditions and technological developments, new and emerging marine toxins are being detected in regions where they were previously unknown. This Special Issue highlight studies aiming to the develop detection methods for marine biotoxins for better understanding the dynamics of accumulation/elimination of marine biotoxins and their effects on marine organisms, as well as toxin exposure studies that aim to evaluate the risks associated with the consumption of contaminated seafood.

Emerging Marine Biotoxins

Authors: ---
ISBN: 9783039215133 9783039213498 Year: Pages: 206 DOI: 10.3390/books978-3-03921-349-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-12-09 11:49:15
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The emergence of marine and freshwater toxins in geographical areas where they have never been reported before is a concern due to the considerable impact on (sea)food contamination, and consequently, on public health. Several groups of marine biotoxins, in particular tetrodotoxins, ciguatoxins, and palytoxins, are included among the relevant marine biotoxins that have recently emerged in several coastal areas. A similar situation has been observed in freshwater, where cyanobacterial toxins, such as microcystins, could end up in unexpected areas such as the estuaries where shellfish are cultivated. Climate change and the increased availability of nutrients have been considered as the key factors in the expansion of all of these toxins into new areas; however, this could also be due to more intense biological invasions, more sensitive analytical methods, or perhaps even an increased scientific interest in these natural contaminations. The incidences of human intoxications due to the consumption of seafood contaminated with these toxins have made their study an important task to accomplish in order to protect human health. This Special Issue has a focus on a wide variety of emerging biotoxin classes and techniques to identify and quantify them.

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