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Current Drug Metabolism 2018Pathogenic microbes routinely keep encountering different types of stress in their environment such as high osmolarity, high temperature, pH fluctuations in host gut... (Review)
Review
BACKGROUND
Pathogenic microbes routinely keep encountering different types of stress in their environment such as high osmolarity, high temperature, pH fluctuations in host gut etc. They tend to acquire certain small molecular weight molecules, termed osmolytes, so as to handle these challenges and survive in harsh conditions. These osmolytes include some which are self-synthesized by the microorganisms, while majority of them are imbibed from the external environment via osmolyte transporters.
METHODS
In this review, we have discussed work done on osmolytes and their transport systems, which influence upon sustenance and virulence of the pathogens under the given stress conditions.
RESULTS
Osmolytes and their transport systems play vital role in efficient maintenance of cell turgidity and electrolyte levels for proper cell functioning. These molecules don't disturb normal metabolic processes within the microbial cell at all; it rather stabilizes the macromolecules, such as nucleic acids and proteins. Besides, these osmolytes also empower the microbes with the pathogenicity potential under harsh conditions such as salt, pH, temperature stress, and the efficient host immunity.
CONCLUSION
Exploring avenues with respect to osmolyte transport systems is the need of the hour especially in this time where we are facing the evolution of antibiotic resistance in pathogens. Most interestingly, a detailed study of bacterial stress responses would prove to be useful in comprehending what these pathogens face in the host microenvironment, whereby we can manipulate the pathogen survival in human gut, and hence address the menace of pathogenic resistance in humans as well as animals.
Topics: Animals; Bacteria; Carrier Proteins; Humans; Osmolar Concentration; Plasmodium; Protein Stability; Urinary Tract Infections; Virulence
PubMed: 29938617
DOI: 10.2174/1389200219666180625113446 -
Microbes and Infection Jun 2001Pathogenicity islands represent distinct genetic elements encoding virulence factors of pathogenic bacteria. Pathogenicity islands belong to the class of genomic... (Review)
Review
Pathogenicity islands represent distinct genetic elements encoding virulence factors of pathogenic bacteria. Pathogenicity islands belong to the class of genomic islands, which are common genetic elements sharing a set of unifying features. Genomic islands have been acquired by horizontal gene transfer. In recent years many different genomic islands have been discovered in a variety of pathogenic as well as non-pathogenic bacteria. Because they promote genetic variability, genomic islands play an important role in microbial evolution.
Topics: Animals; Bacteria; Base Sequence; Ecology; Evolution, Molecular; Gene Transfer, Horizontal; Genetic Variation; Genome, Bacterial; Humans; Virulence
PubMed: 11418328
DOI: 10.1016/s1286-4579(01)01410-1 -
BMC Plant Biology Apr 2024Oomycetes are filamentous organisms that resemble fungi in terms of morphology and life cycle, primarily due to convergent evolution. The success of pathogenic oomycetes... (Review)
Review
Oomycetes are filamentous organisms that resemble fungi in terms of morphology and life cycle, primarily due to convergent evolution. The success of pathogenic oomycetes lies in their ability to adapt and overcome host resistance, occasionally transitioning to new hosts. During plant infection, these organisms secrete effector proteins and other compounds during plant infection, as a molecular arsenal that contributes to their pathogenic success. Genomic sequencing, transcriptomic analysis, and proteomic studies have revealed highly diverse effector repertoires among different oomycete pathogens, highlighting their adaptability and evolution potential.The obligate biotrophic oomycete Plasmopara viticola affects grapevine plants (Vitis vinifera L.) causing the downy mildew disease, with significant economic impact. This disease is devastating in Europe, leading to substantial production losses. Even though Plasmopara viticola is a well-known pathogen, to date there are scarce reviews summarising pathogenicity, virulence, the genetics and molecular mechanisms of interaction with grapevine.This review aims to explore the current knowledge of the infection strategy, lifecycle, effector molecules, and pathogenicity of Plasmopara viticola. The recent sequencing of the Plasmopara viticola genome has provided new insights into understanding the infection strategies employed by this pathogen. Additionally, we will highlight the contributions of omics technologies in unravelling the ongoing evolution of this oomycete, including the first in-plant proteome analysis of the pathogen.
Topics: Oomycetes; Plant Diseases; Vitis; Virulence; Biological Evolution; Host-Pathogen Interactions
PubMed: 38658826
DOI: 10.1186/s12870-024-05037-0 -
Infectious Agents and Disease Jan 1996The term pathogenicity island has been used to refer to large chromosomal regions in pathogenic bacteria that encode virulence genes. This article reviews the recent... (Review)
Review
The term pathogenicity island has been used to refer to large chromosomal regions in pathogenic bacteria that encode virulence genes. This article reviews the recent history of this term and considers what characteristics define a pathogenicity island. It appears that pathogenicity islands can confer complex virulence phenotypes and were acquired by bacteria from unrelated organisms, leading to interesting hypotheses about how bacterial pathogens evolved. It is likely that mechanisms that generate pathogenicity islands continue to operate and may contribute to the emergence of bacterial pathogens with new virulence properties.
Topics: Bacteria; Bacterial Infections; Biological Evolution; Chromosomes, Bacterial; Disease Outbreaks; Genes, Bacterial; Humans; Multigene Family; Phenotype; Virulence
PubMed: 8789594
DOI: No ID Found -
Current Genetics Aug 2016From the first identification of bacteria as a causative agent of disease, researchers have been developing methods and techniques to understand their pathogenic... (Review)
Review
From the first identification of bacteria as a causative agent of disease, researchers have been developing methods and techniques to understand their pathogenic processes. For decades, this work has been limited to looking at a small number of genetically manipulatable isolates in in vitro assays or animal models of infection. Despite these limitations such work has facilitated the development of successful therapeutic strategies, most notably vaccines that target specific virulence-related features. There are however many antimicrobial resistant pathogens for which vaccination strategies have not worked, as we simply do not know enough about how they cause disease. We are however at the dawn of a new era in the study of microbial pathogenicity, where large collections of bacteria isolated directly from human infections can be sequenced and assayed to identify the bacterial features that affect disease severity in humans. Here, we describe our attempt to perform such a study focussed on the major human pathogen Staphylococcus aureus, which demonstrates the step changes such approaches can make to understanding microbial pathogenicity.
Topics: Animals; Bacteria; Bacterial Infections; Genome, Bacterial; Genome-Wide Association Study; Genomics; Host-Pathogen Interactions; Humans; Staphylococcal Infections; Staphylococcus aureus; Virulence
PubMed: 26898530
DOI: 10.1007/s00294-016-0576-4 -
International Journal of Molecular... Aug 2023is a devastating fungal pathogen that causes severe crop losses worldwide. It is of vital importance to understand its pathogenic mechanism for disease control. Through...
is a devastating fungal pathogen that causes severe crop losses worldwide. It is of vital importance to understand its pathogenic mechanism for disease control. Through a forward genetic screen combined with next-generation sequencing, a putative protein kinase, Cak1, was found to be involved in the growth and pathogenicity of . Knockout and complementation experiments confirmed that deletions in caused defects in mycelium and sclerotia development, as well as appressoria formation and host penetration, leading to complete loss of virulence. These findings suggest that Cak1 is essential for the growth, development, and pathogenicity of . Therefore, Cak1 could serve as a potential target for the control of infection through host-induced gene silencing (HIGS), which could increase crop resistance to the pathogen.
Topics: Virulence; Ascomycota; Gene Silencing; High-Throughput Nucleotide Sequencing
PubMed: 37628791
DOI: 10.3390/ijms241612610 -
Microbiology and Molecular Biology... Jun 1997Bacterial pathogens employ a number of genetic strategies to cause infection and, occasionally, disease in their hosts. Many of these virulence factors and their... (Review)
Review
Bacterial pathogens employ a number of genetic strategies to cause infection and, occasionally, disease in their hosts. Many of these virulence factors and their regulatory elements can be divided into a smaller number of groups based on the conservation of similar mechanisms. These common themes are found throughout bacterial virulence factors. For example, there are only a few general types of toxins, despite a large number of host targets. Similarly, there are only a few conserved ways to build the bacterial pilus and nonpilus adhesins used by pathogens to adhere to host substrates. Bacterial entry into host cells (invasion) is a complex mechanism. However, several common invasion themes exist in diverse microorganisms. Similarly, once inside a host cell, pathogens have a limited number of ways to ensure their survival, whether remaining within a host vacuole or by escaping into the cytoplasm. Avoidance of the host immune defenses is key to the success of a pathogen. Several common themes again are employed, including antigenic variation, camouflage by binding host molecules, and enzymatic degradation of host immune components. Most virulence factors are found on the bacterial surface or secreted into their immediate environment, yet virulence factors operate through a relatively small number of microbial secretion systems. The expression of bacterial pathogenicity is dependent upon complex regulatory circuits. However, pathogens use only a small number of biochemical families to express distinct functional factors at the appropriate time that causes infection. Finally, virulence factors maintained on mobile genetic elements and pathogenicity islands ensure that new strains of pathogens evolve constantly. Comprehension of these common themes in microbial pathogenicity is critical to the understanding and study of bacterial virulence mechanisms and to the development of new "anti-virulence" agents, which are so desperately needed to replace antibiotics.
Topics: Bacteria; Bacterial Adhesion; Bacterial Infections; Bacterial Toxins; Gene Expression Regulation, Bacterial; Phagocytes; Virulence
PubMed: 9184008
DOI: 10.1128/mmbr.61.2.136-169.1997 -
Molecular Oral Microbiology Dec 2012Recent advancements in the periodontal research field are consistent with a new model of pathogenesis according to which periodontitis is initiated by a synergistic and... (Review)
Review
Recent advancements in the periodontal research field are consistent with a new model of pathogenesis according to which periodontitis is initiated by a synergistic and dysbiotic microbial community rather than by select 'periopathogens', such as the 'red complex'. In this polymicrobial synergy, different members or specific gene combinations within the community fulfill distinct roles that converge to shape and stabilize a disease-provoking microbiota. One of the core requirements for a potentially pathogenic community to arise involves the capacity of certain species, termed 'keystone pathogens', to modulate the host response in ways that impair immune surveillance and tip the balance from homeostasis to dysbiosis. Keystone pathogens also elevate the virulence of the entire microbial community through interactive communication with accessory pathogens. Other important core functions for pathogenicity require the expression of diverse molecules (e.g. appropriate adhesins, cognate receptors, proteolytic enzymes and proinflammatory surface structures/ligands), which in combination act as community virulence factors to nutritionally sustain a heterotypic, compatible and proinflammatory microbial community that elicits a non-resolving and tissue-destructive host response. On the basis of the fundamental concepts underlying this model of periodontal pathogenesis, that is, polymicrobial synergy and dysbiosis, we term it the PSD model.
Topics: Bacteria; Host-Pathogen Interactions; Humans; Immune Evasion; Inflammation Mediators; Microbial Consortia; Periodontitis; Symbiosis; Virulence
PubMed: 23134607
DOI: 10.1111/j.2041-1014.2012.00663.x -
Reviews of Infectious Diseases 1988Microbial genetics and molecular cloning now permit us to routinely isolate specific genes from a variety of microbial pathogens. Obviously not all genes from pathogenic... (Review)
Review
Microbial genetics and molecular cloning now permit us to routinely isolate specific genes from a variety of microbial pathogens. Obviously not all genes from pathogenic microorganisms play a role in pathogenicity or virulence. Just as Koch's postulates were formulated to identify the causal relationship between an organism and a specific disease, the notion is presented here that a form of molecular Koch's postulates is needed when examining the potential role of genes and their products in the pathogenesis of infection and disease.
Topics: Animals; Bacteria; Cloning, Molecular; Genes, Bacterial; Humans; Mutation; Virulence
PubMed: 3055197
DOI: 10.1093/cid/10.supplement_2.s274 -
Plant Disease Mar 2021A total of 201 isolates of (the causal agent of rice blast) were collected from three rice ecosystems (upland, lowland, and swampy) in five regions of Indonesia (West...
A total of 201 isolates of (the causal agent of rice blast) were collected from three rice ecosystems (upland, lowland, and swampy) in five regions of Indonesia (West Java, Lampung, South Sumatra, Kalimantan, and Bali). Their pathogenicities were characterized based on the patterns of reaction of 25 differential varieties (DVs) and the susceptible control Lijiangxintuanheigu (LTH), which was susceptible to all blast isolates. A high proportion of isolates (>80.0%) were virulent to DVs for resistance genes , , , , and (t), and a low proportion of isolates (<12.9%) were virulent to DVs for , , , , , and (t). Virulence to the other DVs for , , , (t), (t), , , , (two lines), (two lines), (t), and (t) showed intermediate frequencies from 20.0 to 80.0%. These isolates were classified into three cluster groups, Ia, Ib, and II, and the frequencies of cluster groups varied between the three ecosystems and the five regions. The frequencies of cluster groups varied between ecosystems and regions, and races varied according to the ecosystems. A total of 27 standard differential blast isolates (SDBIs) were selected from the 201 isolates collected. The set of 25 DVs and these 27 SDBIs will be used as a new differential system for analysis of the pathogenicity of blast isolates and analysis of resistance genes in rice cultivars, which will contribute to building a durable protection system against blast disease in Indonesia.
Topics: Ascomycota; Ecosystem; Indonesia; Magnaporthe; Oryza; Plant Diseases; Virulence
PubMed: 32787657
DOI: 10.1094/PDIS-05-20-0949-RE