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Journal of Insect Science (Online) Jul 2020The diversity and ecological variety of Holometabola foregrounds a wide array of dynamic symbiotic relationships with gut-dwelling bacteria. A review of the literature... (Review)
Review
The diversity and ecological variety of Holometabola foregrounds a wide array of dynamic symbiotic relationships with gut-dwelling bacteria. A review of the literature highlights that holometabolous insects rely on both obligate bacteria and facultative bacteria living in their guts to satisfy a number of physiological needs. The driving forces behind these differing relationships can be hypothesized through the scrutiny of bacterial associations with host gut morphology, and transmission of bacteria within a given host taxon. Our knowledge of the evolution of facultative or obligate symbiotic bacteria in holometabolan systems is further enhanced by an assessment of the various services the bacteria provide, including nutrition, immune system health, and development. The diversity of Holometabola can thus be examined through an assessment of known bacterial partnerships within the orders of Holometabola.
Topics: Animals; Bacteria; Bacterial Physiological Phenomena; Gastrointestinal Microbiome; Holometabola; Symbiosis
PubMed: 32809024
DOI: 10.1093/jisesa/ieaa084 -
Nature Reviews. Microbiology May 2018Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse... (Review)
Review
Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, hopanoid-producing bacteria have been cultured, and tools to manipulate hopanoid biosynthesis and detect hopanoids are improving. However, we still have much to learn regarding how hopanoid production is regulated, how hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of hopanoids thus offers rich opportunities for discovery.
Topics: Bacteria; Cell Membrane; Lipid Metabolism; Lipids; Plants
PubMed: 29456243
DOI: 10.1038/nrmicro.2017.173 -
Current Opinion in Microbiology Jun 2023The rhizosphere is a chemically complex environment that harbors a strikingly diverse microbial community. The past few decades have seen a rapid growth in the body of... (Review)
Review
The rhizosphere is a chemically complex environment that harbors a strikingly diverse microbial community. The past few decades have seen a rapid growth in the body of literature on plant-microbe-microbe interactions and plant health. Thus, the aim of this paper is to review current knowledge on plant-microbe-microbe (specifically bacteria) interactions in the rhizosphere and how these influence rhizosphere microbiomes and impact plant health. This article discusses (i) how the plant recruits beneficial rhizosphere bacteria and ii) how competition between rhizosphere bacteria and mechanisms/weapons employed in bacteria-bacteria competition shapes rhizosphere microbiome and in turn affects plant heath. The discussion mainly focuses on interference competition, characterized by production of specialized metabolites (antibacterial compounds) and exploitative competition where a bacterial strain restricts the competitor's access to nutrients such as through secretion of siderophores that could allude to cooperation. Understanding mechanisms employed in bacteria-bacteria and plant-bacteria interactions could provide insights into how to manipulate microbiomes for improved agricultural outcomes.
Topics: Rhizosphere; Soil Microbiology; Bacteria; Plants; Microbiota
PubMed: 37002974
DOI: 10.1016/j.mib.2023.102297 -
Trends in Pharmacological Sciences Dec 2022Therapeutic proteins are rarely available in oral dosage form because the hostile environment of the human gastrointestinal (GI) tract and their large size make this... (Review)
Review
Therapeutic proteins are rarely available in oral dosage form because the hostile environment of the human gastrointestinal (GI) tract and their large size make this delivery method difficult. Commensal bacteria in the gut face the same situation; however, they not only survive but low levels of their structural components such as lipopolysaccharide (LPS), peptidoglycan, and flagellin are also consistently detectable in the circulatory systems of healthy individuals. This opinion article discusses how gut bacteria survive in the gut, how their components penetrate the body from the perspective of the bacteria's and the host's proactivity, and how orally administered therapeutic proteins may be developed that exploit similar mechanisms to enter the body.
Topics: Humans; Gastrointestinal Microbiome; Gastrointestinal Tract; Bacteria
PubMed: 36057462
DOI: 10.1016/j.tips.2022.08.002 -
Microbiology Spectrum Jun 2016Candida species are the most common infectious fungal species in humans; out of the approximately 150 known species, Candida albicans is the leading pathogenic species,... (Review)
Review
Candida species are the most common infectious fungal species in humans; out of the approximately 150 known species, Candida albicans is the leading pathogenic species, largely affecting immunocompromised individuals. Apart from its role as the primary etiology for various types of candidiasis, C. albicans is known to contribute to polymicrobial infections. Polymicrobial interactions, particularly between C. albicans and bacterial species, have gained recent interest in which polymicrobial biofilm virulence mechanisms have been studied including adhesion, invasion, quorum sensing, and development of antimicrobial resistance. These trans-kingdom interactions, either synergistic or antagonistic, may help modulate the virulence and pathogenicity of both Candida and bacteria while uniquely impacting the pathogen-host immune response. As antibiotic and antifungal resistance increases, there is a great need to explore the intermicrobial cross-talk with a focus on the treatment of Candida-associated polymicrobial infections. This article explores the current literature on the interactions between Candida and clinically important bacteria and evaluates these interactions in the context of pathogenesis, diagnosis, and disease management.
Topics: Animals; Bacteria; Candida albicans; Coinfection; Host-Pathogen Interactions; Humans; Microbial Interactions
PubMed: 27337476
DOI: 10.1128/microbiolspec.VMBF-0030-2016 -
Respiratory Medicine Apr 2018Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections.... (Review)
Review
Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections. The most commonly encountered pathogens during this period are gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa …), but gram-positive coccus such as Staphylococcus aureus or Streptococcus pneumoniae and anaerobic bacteria can also be found. Empirical antibiotic therapy should be guided by previous colonisation of the recipient and bacterial resistance pattern in the hospital. Six months after transplantation, pneumonias are mostly due to community-acquired bacteria (S. pneumonia, H. influenza, Mycoplasma, Chlamydia and others). Opportunistic pathogens take advantage of the state of immunosuppression which is usually highest from one to six months after transplantation. During this period, but also occurring many years later in the setting of a chronically depressed immune system, bacterial pathogens with low intrinsic virulence can cause pneumonia. The diagnosis of pneumonia caused by opportunistic pathogens can be challenging. The delay in diagnosis preventing the early instauration of adequate treatment in kidney transplant recipients with a depressed immune system, frequently coupled with co-morbid conditions and a state of frailty, will affect prognosis and outcome, increasing morbidity and mortality. This review will focus on the most common opportunistic bacterial pathogens causing pneumonia in kidney transplant recipients: Legionella, Nocardia, Mycobacterium tuberculosis/nontuberculous, and Rhodococcus. Recognition of their specificities in the setting of immunosuppression will allow early diagnosis, crucial for initiation of effective therapy and successful outcome. Interactions with immunosuppressive therapy should be considered as well as reducing immunosuppression if necessary.
Topics: Aged; Anti-Bacterial Agents; Bacteria; Cross Infection; Humans; Immunosuppression Therapy; Kidney Transplantation; Legionella; Male; Middle Aged; Mycobacterium; Nocardia; Opportunistic Infections; Pneumonia, Bacterial; Prognosis; Rhodococcus; Transplant Recipients
PubMed: 29605219
DOI: 10.1016/j.rmed.2018.02.022 -
Current Opinion in Microbiology Feb 2020Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious... (Review)
Review
Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious communities are often studied in pure culture for their ability to cause disease. However, recent studies have begun to focus on the role of polymicrobial interactions in disease outcomes. Pseudomonas aeruginosa can colonize patients with chronic lung diseases for years and sometimes even decades. During these prolonged infections, P. aeruginosa encounters a plethora of other microbes including bacteria, fungi, and viruses. The interactions between these microbes can vary greatly, ranging from antagonistic to synergistic depending on specific host and microbe-associated contexts. These additional layers of complexity associated with chronic P. aeruginosa infections must be considered in future studies in order to fully understand the physiology of infection. Such studies focusing on the entire infectious community rather than individual species may ultimately lead to more effective therapeutic design for persistent polymicrobial infections.
Topics: Animals; Bacteria; Humans; Lung; Lung Diseases; Microbial Interactions; Microbiota; Pseudomonas aeruginosa
PubMed: 32062024
DOI: 10.1016/j.mib.2020.01.014 -
Cell Chemical Biology Jan 2016Recent studies have illuminated a remarkable diversity and abundance of microbes living on and within the human body. While we are beginning to appreciate associations... (Review)
Review
Recent studies have illuminated a remarkable diversity and abundance of microbes living on and within the human body. While we are beginning to appreciate associations of certain bacteria and genes with particular host physiological states, considerable information is lacking about the relevant functional activities of the human microbiota. The human gut microbiome encodes tremendous potential for the biosynthesis and transformation of compounds that are important for both microbial and host physiology. Implementation of chemical knowledge and techniques will be required to improve our understanding of the biochemical diversity of the human microbiota. Such efforts include the characterization of novel microbial enzymes and pathways, isolation of microbial natural products, and development of tools to modulate biochemical functions of the gut microbiota. Ultimately, a molecular understanding of gut microbial activities will be critical for elucidating and manipulating these organisms' contributions to human health and disease.
Topics: Bacteria; Biological Products; Gastrointestinal Microbiome; Gastrointestinal Tract; Health; Humans; Metabolic Networks and Pathways
PubMed: 26933733
DOI: 10.1016/j.chembiol.2015.12.008 -
Genomics Jul 2019Genome sequencing is commonly used in research laboratories right now thanks to the rise of high-throughput sequencing with higher speed and output-to-cost ratios. Here,... (Review)
Review
Genome sequencing is commonly used in research laboratories right now thanks to the rise of high-throughput sequencing with higher speed and output-to-cost ratios. Here, we summarized the application of genomics in different aspects of plant bacterial pathosystems. Genomics has been used in studying the mechanisms of plant-bacteria interactions, and host specificity. It also helps with taxonomy, study of non-cultured bacteria, identification of causal agent, single cell sequencing, population genetics, and meta-transcriptomic. Overall, genomics has significantly improved our understanding of plant-microbe interaction.
Topics: Bacteria; Genome, Bacterial; Genomics; Host-Pathogen Interactions; Plants
PubMed: 29678682
DOI: 10.1016/j.ygeno.2018.04.011 -
Journal of Medical Microbiology Nov 2019Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial... (Review)
Review
Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.
Topics: Animals; Bacteria; Bacterial Physiological Phenomena; Biofilms; Humans; Mouth
PubMed: 31524581
DOI: 10.1099/jmm.0.001063