Shared and distinct mechanisms of iron acquisition by bacterial and fungal pathogens of humans

PubMed Central

Caza, Mélissa; Kronstad, James W.

2013-01-01

Iron is the most abundant transition metal in the human body and its bioavailability is stringently controlled. In particular, iron is tightly bound to host proteins such as transferrin to maintain homeostasis, to limit potential damage caused by iron toxicity under physiological conditions and to restrict access by pathogens. Therefore, iron acquisition during infection of a human host is a challenge that must be surmounted by every successful pathogenic microorganism. Iron is essential for bacterial and fungal physiological processes such as DNA replication, transcription, metabolism, and energy generation via respiration. Hence, pathogenic bacteria and fungi have developed sophisticated strategies to gain access to iron from host sources. Indeed, siderophore production and transport, iron acquisition from heme and host iron-containing proteins such as hemoglobin and transferrin, and reduction of ferric to ferrous iron with subsequent transport are all strategies found in bacterial and fungal pathogens of humans. This review focuses on a comparison of these strategies between bacterial and fungal pathogens in the context of virulence and the iron limitation that occurs in the human body as a mechanism of innate nutritional defense. PMID:24312900

Know your neighbor: Microbiota and host epithelial cells interact locally to control intestinal function and physiology.

PubMed

Sommer, Felix; Bäckhed, Fredrik

2016-05-01

Interactions between the host and its associated microbiota differ spatially and the local cross talk determines organ function and physiology. Animals and their organs are not uniform but contain several functional and cellular compartments and gradients. In the intestinal tract, different parts of the gut carry out different functions, tissue structure varies accordingly, epithelial cells are differentially distributed and gradients exist for several physicochemical parameters such as nutrients, pH, or oxygen. Consequently, the microbiota composition also differs along the length of the gut, but also between lumen and mucosa of the same intestinal segment, and even along the crypt-villus axis in the epithelium. Thus, host-microbiota interactions are highly site-specific and the local cross talk determines intestinal function and physiology. Here we review recent advances in our understanding of site-specific host-microbiota interactions and discuss their functional relevance for host physiology. © 2016 WILEY Periodicals, Inc.

Insights into Host Cell Modulation and Induction of New Cells by the Corn Smut Ustilago maydis.

PubMed

Redkar, Amey; Matei, Alexandra; Doehlemann, Gunther

2017-01-01

Many filamentous fungal pathogens induce drastic modulation of host cells causing abnormal infectious structures such as galls, or tumors that arise as a result of re-programming in the original developmental cell fate of a colonized host cell. Developmental consequences occur predominantly with biotrophic phytopathogens. This suggests that these host structures result as an outcome of efficient defense suppression and intimate fungal-host interaction to suit the pathogen's needs for completion of its infection cycle. This mini-review mainly summarizes host cell re-programming that occurs in the Ustilago maydis - maize interaction, in which the pathogen deploys cell-type specific effector proteins with varying activities. The fungus senses the physiological status and identity of colonized host cells and re-directs the endogenous developmental program of its host. The disturbance of host cell physiology and cell fate leads to novel cell shapes, increased cell size, and/or the number of host cells. We particularly highlight the strategies of U. maydis to induce physiologically varied host organs to form the characteristic tumors in both vegetative and floral parts of maize.

Plant-Pathogen Effectors: Cellular Probes Interfering with Plant Defenses in Spatial and Temporal Manners

PubMed Central

Toruño, Tania Y.; Stergiopoulos, Ioannis; Coaker, Gitta

2017-01-01

Plants possess large arsenals of immune receptors capable of recognizing all pathogen classes. To cause disease, pathogenic organisms must be able to overcome physical barriers, suppress or evade immune perception, and derive nutrients from host tissues. Consequently, to facilitate some of these processes, pathogens secrete effector proteins that promote colonization. This review covers recent advances in the field of effector biology, focusing on conserved cellular processes targeted by effectors from diverse pathogens. The ability of effectors to facilitate pathogen entry into the host interior, suppress plant immune perception, and alter host physiology for pathogen benefit is discussed. Pathogens also deploy effectors in a spatial and temporal manner, depending on infection stage. Recent advances have also enhanced our understanding of effectors acting in specific plant organs and tissues. Effectors are excellent cellular probes that facilitate insight into biological processes as well as key points of vulnerability in plant immune signaling networks. PMID:27359369

Cellular and Physiological Effects of Anthrax Exotoxin and Its Relevance to Disease

PubMed Central

Lowe, David E.; Glomski, Ian J.

2012-01-01

Bacillus anthracis, the causative agent of anthrax, secretes a tri-partite exotoxin that exerts pleiotropic effects on the host. The purification of the exotoxin components, protective antigen, lethal factor, and edema factor allowed the rapid characterization of their physiologic effects on the host. As molecular biology matured, interest focused on the molecular mechanisms and cellular alterations induced by intoxication. Only recently have researchers begun to connect molecular and cellular knowledge back to the broader physiological effects of the exotoxin. This review focuses on the progress that has been made bridging molecular knowledge back to the exotoxin’s physiological effects on the host. PMID:22919667

You are what you eat.

PubMed

Lewis, Zenobia; Heys, Chloe; Prescott, Mark; Lizé, Anne

2014-07-01

Gut bacteria is now considered as an additional host organ, and it has been shown that they have important influences on host developmental and physiological processes. More recently gut bacteria have additionally been implicated in behavioral processes. We showed that in two species of Drosophila, gut bacteria variation affects behavior, altering partner investment in copulation in relation to whether individuals were familiar (i.e., having developed in the same environment), or were related. This suggests that gut bacteria play a role in kin recognition in these species. We suggest that this phenomenon is associated with gut bacteria influencing the scent profiles used by Drosophila in mate choice.

Influence of fungicides on gas exchange of pecan foliage

USDA-ARS?s Scientific Manuscript database

There are several fungicide chemistries used for disease control on pecan (Carya illinoinensis), but there is little or no knowledge of subtle short- or long-term side-effects of these chemistries on host physiological processes, including photosynthesis (Pn). This study quantifies the impact of se...

The Impact of Protein Phosphorylation on Chlamydial Physiology

PubMed Central

Claywell, Ja E.; Matschke, Lea M.; Fisher, Derek J.

2016-01-01

Chlamydia are Gram negative bacterial pathogens responsible for disease in humans and economically important domesticated animals. As obligate intracellular bacteria, they must gain entry into a host cell where they propagate within a parasitophorous organelle that serves as an interactive interface between the bacterium and the host. Nutrient acquisition, growth, and evasion of host defense mechanisms occur from this location. In addition to these cellular and bacterial dynamics, Chlamydia differentiate between two morphologically distinct forms, the elementary body and reticulate body, that are optimized for either extracellular or intracellular survival, respectively. The mechanisms regulating and mediating these diverse physiological events remain largely unknown. Reversible phosphorylation, including classical two-component signaling systems, partner switching mechanisms, and the more recently appreciated bacterial Ser/Thr/Tyr kinases and phosphatases, has gained increasing attention for its role in regulating important physiological processes in bacteria including metabolism, development, and virulence. Phosphorylation modulates these events via rapid and reversible modification of protein substrates leading to changes in enzyme activity, protein oligomerization, cell signaling, and protein localization. The characterization of several conserved chlamydial protein kinases and phosphatases along with phosphoproteome analysis suggest that Chlamydia are capable of global and growth stage-specific protein phosphorylation. This mini review will highlight the current knowledge of protein phosphorylation in Chlamydia and its potential role in chlamydial physiology and, consequently, virulence. Comparisons with other minimal genome intracellular bacterial pathogens also will be addressed with the aim of illustrating the importance of this understudied regulatory mechanism on pathogenesis and the principle questions that remain unanswered. PMID:28066729

Cellular Signaling Pathways and Posttranslational Modifications Mediated by Nematode Effector Proteins.

PubMed

Hewezi, Tarek

2015-10-01

Plant-parasitic cyst and root-knot nematodes synthesize and secrete a suite of effector proteins into infected host cells and tissues. These effectors are the major virulence determinants mediating the transformation of normal root cells into specialized feeding structures. Compelling evidence indicates that these effectors directly hijack or manipulate refined host physiological processes to promote the successful parasitism of host plants. Here, we provide an update on recent progress in elucidating the molecular functions of nematode effectors. In particular, we emphasize how nematode effectors modify plant cell wall structure, mimic the activity of host proteins, alter auxin signaling, and subvert defense signaling and immune responses. In addition, we discuss the emerging evidence suggesting that nematode effectors target and recruit various components of host posttranslational machinery in order to perturb the host signaling networks required for immunity and to regulate their own activity and subcellular localization. © 2015 American Society of Plant Biologists. All Rights Reserved.

The missing link in parasite manipulation of host behaviour.

PubMed

Herbison, Ryan; Lagrue, Clement; Poulin, Robert

2018-04-03

The observation that certain species of parasite my adaptively manipulate its host behaviour is a fascinating phenomenon. As a result, the recently established field of 'host manipulation' has seen rapid expansion over the past few decades with public and scientific interest steadily increasing. However, progress appears to falter when researchers ask how parasites manipulate behaviour, rather than why. A vast majority of the published literature investigating the mechanistic basis underlying behavioural manipulation fails to connect the establishment of the parasite with the reported physiological changes in its host. This has left researchers unable to empirically distinguish/identify adaptive physiological changes enforced by the parasites from pathological side effects of infection, resulting in scientists relying on narratives to explain results, rather than empirical evidence. By contrasting correlative mechanistic evidence for host manipulation against rare cases of causative evidence and drawing from the advanced understanding of physiological systems from other disciplines it is clear we are often skipping over a crucial step in host-manipulation: the production, potential storage, and release of molecules (manipulation factors) that must create the observed physiological changes in hosts if they are adaptive. Identifying these manipulation factors, via associating gene expression shifts in the parasite with behavioural changes in the host and following their effects will provide researchers with a bottom-up approach to unraveling the mechanisms of behavioural manipulation and by extension behaviour itself.

The Role of Reactive-Oxygen-Species in Microbial Persistence and Inflammation

PubMed Central

Spooner, Ralee; Yilmaz, Özlem

2011-01-01

The mechanisms of chronic infections caused by opportunistic pathogens are of keen interest to both researchers and health professionals globally. Typically, chronic infectious disease can be characterized by an elevation in immune response, a process that can often lead to further destruction. Reactive-Oxygen-Species (ROS) have been strongly implicated in the aforementioned detrimental response by host that results in self-damage. Unlike excessive ROS production resulting in robust cellular death typically induced by acute infection or inflammation, lower levels of ROS produced by host cells are increasingly recognized to play a critical physiological role for regulating a variety of homeostatic cellular functions including growth, apoptosis, immune response, and microbial colonization. Sources of cellular ROS stimulation can include “danger-signal-molecules” such as extracellular ATP (eATP) released by stressed, infected, or dying cells. Particularly, eATP-P2X7 receptor mediated ROS production has been lately found to be a key modulator for controlling chronic infection and inflammation. There is growing evidence that persistent microbes can alter host cell ROS production and modulate eATP-induced ROS for maintaining long-term carriage. Though these processes have yet to be fully understood, exploring potential positive traits of these “injurious” molecules could illuminate how opportunistic pathogens maintain persistence through physiological regulation of ROS signaling. PMID:21339989

Biological causal links on physiological and evolutionary time scales.

PubMed

Karmon, Amit; Pilpel, Yitzhak

2016-04-26

Correlation does not imply causation. If two variables, say A and B, are correlated, it could be because A causes B, or that B causes A, or because a third factor affects them both. We suggest that in many cases in biology, the causal link might be bi-directional: A causes B through a fast-acting physiological process, while B causes A through a slowly accumulating evolutionary process. Furthermore, many trained biologists tend to consistently focus at first on the fast-acting direction, and overlook the slower process in the opposite direction. We analyse several examples from modern biology that demonstrate this bias (codon usage optimality and gene expression, gene duplication and genetic dispensability, stem cell division and cancer risk, and the microbiome and host metabolism) and also discuss an example from linguistics. These examples demonstrate mutual effects between the fast physiological processes and the slow evolutionary ones. We believe that building awareness of inference biases among biologists who tend to prefer one causal direction over another could improve scientific reasoning.

How dying cells alert the immune system to danger

PubMed Central

Kono, Hajime; Rock, Kenneth L.

2009-01-01

When a cell dies in vivo the event does not go unnoticed. The host has evolved mechanisms to detect the death of cells and rapidly investigate the nature of their demise. If cell death is a result of natural causes, that is, it is part of normal physiological processes, then there is little threat to the organism. In this situation, little else is done other than removing the corpse. However, if cells have died as the consequence of some violence or disease, then both defence and repair mechanisms are mobilized. The importance of this process to host defence and disease pathogenesis has only been appreciated relatively recently. This article will review our current knowledge of these processes. PMID:18340345

Exploring the proteomic characteristics of the Escherichia coli B and K-12 strains in different cellular compartments.

PubMed

Han, Mee-Jung

2016-07-01

Escherichia coli, one of the well-characterized prokaryotes, has been the most widely used bacterial host in scientific studies and industrial applications. Many different strains have been developed for the widespread use of E. coli in biotechnology, and selecting an ideal host to produce a specific protein of interest is a critical step in developing a production process. The E. coli B and K-12 strains are among the most frequently used bacterial hosts for the production of recombinant proteins as well as small-molecule metabolites such as amino acids, biofuels, carboxylic acids, diamines, and others. However, both strains have distinctive differences in genotypic and phenotypic attributes, and their behaviors can still be unpredictable at times, especially while expressing a recombinant protein. Therefore, in this review, an in-depth analysis of the physiological behavior on the proteomic level was performed, wherein the particularly distinct proteomic differences between the E. coli B and K-12 strains were investigated in the four distinctive cellular compartments. Interesting differences in the proteins associated with key cellular properties including cell growth, protein production and quality, cellular tolerance, and motility were observed between the two representative strains. The resulting enhancement of knowledge regarding host physiology that is summarized herein is expected to contribute to the acceleration of strain improvements and optimization for biotechnology-related processes. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Cellstat--A continuous culture system of a bacteriophage for the study of the mutation rate and the selection process at the DNA level

NASA Astrophysics Data System (ADS)

Husimi, Yuzuru; Nishigaki, Koichi; Kinoshita, Yasunori; Tanaka, Toyosuke

1982-04-01

A bacteriophage is continuously cultured in the flow of the host bacterial cell under the control of a minicomputer. In the culture, the population of the noninfected cell is kept constant by the endogeneous regulation mechanism, so it is called the ''cellstat'' culture. Due to the high dilution rate of the host cell, the mutant cell cannot be selected in the cellstat. Therefore, the cellstat is suitable for the study of the mutation rate and the selection process of a bacteriophage under well-defined environmental conditions (including physiological condition of the host cell) without being interfered by host-cell mutations. Applications to coliphage fd, a secretion type phage, are shown as a measurement example. A chimera between fd and a plasmid pBR322 is cultured more than 100 h. The process of population changeovers by deletion mutants indicates that the deletion hot spots exist in this cloning vector and that this apparatus can be used also for testing instability of a recombinant DNA.

Physiology and Genetics of Tree-Phytophage Interactions

Treesearch

Frances Lieutier; William J. Mattson; Michael R. Wagner

1999-01-01

Interactions between trees and phytophagous organisms represent an important fundamental process in the evolution of forest ecosystems. Through evolutionary time, the special traits of trees have lead the herbivore populations to differentiate and evolve in order to cope with the variability in natural resistance mechanisms of their hosts. Conversely, damage by...

Parasitism and the biodiversity-functioning relationship

USGS Publications Warehouse

Frainer, André; McKie, Brendan G.; Amundsen, Per-Arne; Knudsen, Rune; Lafferty, Kevin D.

2018-01-01

Biodiversity affects ecosystem functioning.Biodiversity may decrease or increase parasitism.Parasites impair individual hosts and affect their role in the ecosystem.Parasitism, in common with competition, facilitation, and predation, could regulate BD-EF relationships.Parasitism affects host phenotypes, including changes to host morphology, behavior, and physiology, which might increase intra- and interspecific functional diversity.The effects of parasitism on host abundance and phenotypes, and on interactions between hosts and the remaining community, all have potential to alter community structure and BD-EF relationships.Global change could facilitate the spread of invasive parasites, and alter the existing dynamics between parasites, communities, and ecosystems.Species interactions can influence ecosystem functioning by enhancing or suppressing the activities of species that drive ecosystem processes, or by causing changes in biodiversity. However, one important class of species interactions – parasitism – has been little considered in biodiversity and ecosystem functioning (BD-EF) research. Parasites might increase or decrease ecosystem processes by reducing host abundance. Parasites could also increase trait diversity by suppressing dominant species or by increasing within-host trait diversity. These different mechanisms by which parasites might affect ecosystem function pose challenges in predicting their net effects. Nonetheless, given the ubiquity of parasites, we propose that parasite–host interactions should be incorporated into the BD-EF framework.

The Neuroendocrinology of the Microbiota-Gut-Brain Axis: A Behavioural Perspective.

PubMed

Cussotto, Sofia; Sandhu, Kiran V; Dinan, Timothy G; Cryan, John F

2018-05-10

The human gut harbours trillions of symbiotic bacteria that play a key role in programming different aspects of host physiology in health and disease. These intestinal microbes are also key components of the gut-brain axis, the bidirectional communication pathway between the gut and the central nervous system (CNS). In addition, the CNS is closely interconnected with the endocrine system to regulate many physiological processes. An expanding body of evidence is supporting the notion that gut microbiota modifications and/or manipulations may also play a crucial role in the manifestation of specific behavioural responses regulated by neuroendocrine pathways. In this review, we will focus on how the intestinal microorganisms interact with elements of the host neuroendocrine system to modify behaviours relevant to stress, eating behaviour, sexual behaviour, social behaviour, cognition and addiction. Copyright © 2018. Published by Elsevier Inc.

Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis

PubMed Central

Barott, Katie L.; Venn, Alexander A.; Perez, Sidney O.; Tambutté, Sylvie; Tresguerres, Martin

2015-01-01

Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H+-ATPase (VHA), which acidifies the symbiosome space down to pH ∼4. Inhibition of VHA results in a significant decrease in average H+ activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts. PMID:25548188

The Bacterial Pathogen Xylella fastidiosa Affects the Leaf Ionome of Plant Hosts during Infection

PubMed Central

De La Fuente, Leonardo; Parker, Jennifer K.; Oliver, Jonathan E.; Granger, Shea; Brannen, Phillip M.; van Santen, Edzard; Cobine, Paul A.

2013-01-01

Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

Dynamics of Lung Defense in Pneumonia: Resistance, Resilience, and Remodeling

PubMed Central

Quinton, Lee J.; Mizgerd, Joseph P.

2015-01-01

Pneumonia is initiated by microbes in the lung, but physiological processes integrating responses across diverse cell types and organ systems dictate the outcome of respiratory infection. Resistance, or actions of the host to eradicate living microbes, in the lungs involves a combination of innate and adaptive immune responses triggered by air-space infection. Resilience, or the ability of the host tissues to withstand the physiologically damaging effects of microbial and immune activities, is equally complex, precisely regulated, and determinative. Both immune resistance and tissue resilience are dynamic and change throughout the lifetime, but we are only beginning to understand such remodeling and how it contributes to the incidence of severe pneumonias, which diminishes as childhood progresses and then increases again among the elderly. Here, we review the concepts of resistance, resilience, and remodeling as they apply to pneumonia, highlighting recent advances and current significant knowledge gaps. PMID:25148693

Role of GATA transcription factor ELT-2 and p38 MAPK PMK-1 in recovery from acute P. aeruginosa infection in C. elegans

PubMed Central

Head, Brian P.; Olaitan, Abiola O.; Aballay, Alejandro

2017-01-01

ABSTRACT Infectious diseases caused by bacterial pathogens reduce the fitness of their associated host but are generally limited in duration. In order for the diseased host to regain any lost fitness upon recovery, a variety of molecular, cellular, and physiological processes must be employed. To better understand mechanisms underlying the recovery process, we have modeled an acute Pseudomonas aeruginosa infection in C. elegans using brief exposures to this pathogen and subsequent antibiotic treatment. To identify host genes altered during recovery from P. aeruginosa infection, we performed whole genome expression profiling. The analysis of this dataset indicated that the activity of the host immune system is down-regulated upon recovery and revealed shared and pathogen-specific host responses during recovery. We determined that the GATA transcription factor ELT-2 and the p38 MAP kinase PMK-1 are necessary for animals to successfully recover from an acute P. aeruginosa infection. In addition, we found that ELT-2 plays a more prominent and earlier role than PMK-1 during recovery. Our data sheds further light on the molecular mechanisms and transcriptional programs involved in recovery from an acute bacterial infection, which provides a better understanding of the entire infectious disease process. PMID:27600703

Using physiology to understand climate-driven changes in disease and their implications for conservation

PubMed Central

Rohr, Jason R.; Raffel, Thomas R.; Blaustein, Andrew R.; Johnson, Pieter T. J.; Paull, Sara H.; Young, Suzanne

2013-01-01

Controversy persists regarding the contributions of climate change to biodiversity losses, through its effects on the spread and emergence of infectious diseases. One of the reasons for this controversy is that there are few mechanistic studies that explore the links among climate change, infectious disease, and declines of host populations. Given that host–parasite interactions are generally mediated by physiological responses, we submit that physiological models could facilitate the prediction of how host–parasite interactions will respond to climate change, and might offer theoretical and terminological cohesion that has been lacking in the climate change–disease literature. We stress that much of the work on how climate influences host–parasite interactions has emphasized changes in climatic means, despite a hallmark of climate change being changes in climatic variability and extremes. Owing to this gap, we highlight how temporal variability in weather, coupled with non-linearities in responses to mean climate, can be used to predict the effects of climate on host–parasite interactions. We also discuss the climate variability hypothesis for disease-related declines, which posits that increased unpredictable temperature variability might provide a temporary advantage to pathogens because they are smaller and have faster metabolisms than their hosts, allowing more rapid acclimatization following a temperature shift. In support of these hypotheses, we provide case studies on the role of climatic variability in host population declines associated with the emergence of the infectious diseases chytridiomycosis, withering syndrome, and malaria. Finally, we present a mathematical model that provides the scaffolding to integrate metabolic theory, physiological mechanisms, and large-scale spatiotemporal processes to predict how simultaneous changes in climatic means, variances, and extremes will affect host–parasite interactions. However, several outstanding questions remain to be answered before investigators can accurately predict how changes in climatic means and variances will affect infectious diseases and the conservation status of host populations. PMID:27293606

Plant parasitic nematode effectors target host defense and nuclear functions to establish feeding cells.

PubMed

Quentin, Michaëel; Abad, Pierre; Favery, Bruno

2013-01-01

Plant parasitic nematodes are microscopic worms, the most damaging species of which have adopted a sedentary lifestyle within their hosts. These obligate endoparasites have a biotrophic relationship with plants, in which they induce the differentiation of root cells into hypertrophied, multinucleate feeding cells (FCs). Effectors synthesized in the esophageal glands of the nematode are injected into the plant cells via the syringe-like stylet and play a key role in manipulating the host machinery. The establishment of specialized FCs requires these effectors to modulate many aspects of plant cell morphogenesis and physiology, including defense responses. This cell reprogramming requires changes to host nuclear processes. Some proteins encoded by parasitism genes target host nuclei. Several of these proteins were immunolocalized within FC nuclei or shown to interact with host nuclear proteins. Comparative genomics and functional analyses are gradually revealing the roles of nematode effectors. We describe here these effectors and their hypothesized roles in the unique feeding behavior of these pests.

Are fish immune systems really affected by parasites? an immunoecological study of common carp (Cyprinus carpio)

PubMed Central

2011-01-01

Background The basic function of the immune system is to protect an organism against infection in order to minimize the fitness costs of being infected. According to life-history theory, energy resources are in a trade-off between the costly demands of immunity and other physiological demands. Concerning fish, both physiology and immunity are influenced by seasonal changes (i.e. temporal variation) associated to the changes of abiotic factors (such as primarily water temperature) and interactions with pathogens and parasites. In this study, we investigated the potential associations between the physiology and immunocompetence of common carp (Cyprinus carpio) collected during five different periods of a given year. Our sampling included the periods with temporal variability and thus, it presented a different level in exposure to parasites. We analyzed which of two factors, seasonality or parasitism, had the strongest impact on changes in fish physiology and immunity. Results We found that seasonal changes play a key role in affecting the analyzed measurements of physiology, immunity and parasitism. The correlation analysis revealed the relationships between the measures of overall host physiology, immunity and parasite load when temporal variability effect was removed. When analyzing separately parasite groups with different life-strategies, we found that fish with a worse condition status were infected more by monogeneans, representing the most abundant parasite group. The high infection by cestodes seems to activate the phagocytes. A weak relationship was found between spleen size and abundance of trematodes when taking into account seasonal changes. Conclusions Even if no direct trade-off between the measures of host immunity and physiology was confirmed when taking into account the seasonality, it seems that seasonal variability affects host immunity and physiology through energy allocation in a trade-off between life important functions, especially reproduction and fish condition. Host immunity measures were not found to be in a trade-off with the investigated physiological traits or functions, but we confirmed the immunosuppressive role of 11-ketotestosterone on fish immunity measured by complement activity. We suggest that the different parasite life-strategies influence different aspects of host physiology and activate the different immunity pathways. PMID:21708010

Listeria Genomics

NASA Astrophysics Data System (ADS)

Cabanes, Didier; Sousa, Sandra; Cossart, Pascale

The opportunistic intracellular foodborne pathogen Listeria monocytogenes has become a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. Analysis of L. monocytogenes infection has provided considerable insight into how bacteria invade cells, move intracellularly, and disseminate in tissues, as well as tools to address fundamental processes in cell biology. Moreover, the vast amount of knowledge that has been gathered through in-depth comparative genomic analyses and in vivo studies makes L. monocytogenes one of the most well-studied bacterial pathogens. This chapter provides an overview of progress in the exploration of genomic, transcriptomic, and proteomic data in Listeria spp. to understand genome evolution and diversity, as well as physiological aspects of metabolism used by bacteria when growing in diverse environments, in particular in infected hosts.

Fungal genomes that influence basic physiological processes of black grama and fourwing saltbush in arid southwestern rangelands

Treesearch

J.R. Barrow; M. Lucero; P. Osuna-Avila; I. Reyes-Vera; R.E. Aaltonen

2007-01-01

Symbiotic fungi confer multiple benefits such as enhanced photosynthetic rates and drought tolerance in host plants. Shrubs and grasses of southwestern deserts are colonized by symbiotic fungi that cannot be removed by conventional sterilization methods. These fungi were extensively studied in Bouteloua eriopoda (Torr.) Torr. and Atriplex...

Transposable elements re-wire and fine-tune the transcriptome.

PubMed

Cowley, Michael; Oakey, Rebecca J

2013-01-01

What good are transposable elements (TEs)? Although their activity can be harmful to host genomes and can cause disease, they nevertheless represent an important source of genetic variation that has helped shape genomes. In this review, we examine the impact of TEs, collectively referred to as the mobilome, on the transcriptome. We explore how TEs-particularly retrotransposons-contribute to transcript diversity and consider their potential significance as a source of small RNAs that regulate host gene transcription. We also discuss a critical role for the mobilome in engineering transcriptional networks, permitting coordinated gene expression, and facilitating the evolution of novel physiological processes.

Mistletoe ecophysiology: Host-parasite interactions

Treesearch

G. Glatzel; B. W. Geils

2009-01-01

Mistletoes are highly specialized perennial flowering plants adapted to parasitic life on aerial parts of their hosts. In our discussion on the physiological interactions between parasite and host, we focus on water relations, mineral nutrition, and the effect of host vigour. When host photosynthesis is greatest, the xylem water potential of the host is most negative....

[Carbohydrate transport in the cestode Triaenophorus nodulosus].

PubMed

Izvekova, G I

1989-01-01

The data demonstrating the presence of the glucose active transport system in the cestode T. nodulosus are obtained. Kinetic characteristics of the transport are estimated and their dependence on the incubation temperature are shown. Heterogeneity of the worm body in respect to transport processes and their dependence on the physiological state of cestodes are discovered. The absorption of different forms of glucose is studied and the similarity of digestion processes in parasites and their hosts is shown.

Community assembly of a euryhaline fish microbiome during salinity acclimation.

PubMed

Schmidt, Victor T; Smith, Katherine F; Melvin, Donald W; Amaral-Zettler, Linda A

2015-05-01

Microbiomes play a critical role in promoting a range of host functions. Microbiome function, in turn, is dependent on its community composition. Yet, how microbiome taxa are assembled from their regional species pool remains unclear. Many possible drivers have been hypothesized, including deterministic processes of competition, stochastic processes of colonization and migration, and physiological 'host-effect' habitat filters. The contribution of each to assembly in nascent or perturbed microbiomes is important for understanding host-microbe interactions and host health. In this study, we characterized the bacterial communities in a euryhaline fish and the surrounding tank water during salinity acclimation. To assess the relative influence of stochastic versus deterministic processes in fish microbiome assembly, we manipulated the bacterial species pool around each fish by changing the salinity of aquarium water. Our results show a complete and repeatable turnover of dominant bacterial taxa in the microbiomes from individuals of the same species after acclimation to the same salinity. We show that changes in fish microbiomes are not correlated with corresponding changes to abundant taxa in tank water communities and that the dominant taxa in fish microbiomes are rare in the aquatic surroundings, and vice versa. Our results suggest that bacterial taxa best able to compete within the unique host environment at a given salinity appropriate the most niche space, independent of their relative abundance in tank water communities. In this experiment, deterministic processes appear to drive fish microbiome assembly, with little evidence for stochastic colonization. © 2015 John Wiley & Sons Ltd.

Giardia Colonizes and Encysts in High-Density Foci in the Murine Small Intestine

PubMed Central

Barash, N. R.; Nosala, C.; Pham, J. K.; McInally, S. G.; Gourguechon, S.; McCarthy-Sinclair, B.

2017-01-01

ABSTRACT Giardia lamblia is a highly prevalent yet understudied protistan parasite causing significant diarrheal disease worldwide. Hosts ingest Giardia cysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host are largely inferred from laboratory culture and thus may not mirror Giardia physiology in the host. Here, we have developed bioluminescent imaging (BLI) to directly interrogate and quantify the in vivo temporospatial dynamics of Giardia infection, thereby providing an improved murine model to evaluate anti-Giardia drugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine nonuniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high density contributes to the initiation of encystation in laboratory culture. We suggest that these high-density in vivo foci of colonizing and encysting Giardia likely result in localized disruption to the epithelium. This more accurate visualization of giardiasis redefines the dynamics of the in vivo Giardia life cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host. IMPORTANCE Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation. PMID:28656177

Symbioses: a key driver of insect physiological processes, ecological interactions, evolutionary diversification, and impacts on humans

Treesearch

K.D. Klepzig; A.S. Adams; J. Handelsman; K.F. Raffa

2009-01-01

Symbiosis is receiving increased attention among all aspects of biology because of the unifying themes it helps construct across ecological,evolutionary, developmental, semiochemical, and pest management theory. Insects show a vast array of symbiotic relationships with a wide diversity of microorganisms. These relationships may confer a variety of benefits to the host...

Symbioses: A key driver of insect physiological processes, ecological interactions, evolutionary diversification, and impacts on humans

Treesearch

Kier Klepzig; A.S. Adams; J Handelsman; K.F. Raffa

2009-01-01

Symbiosis is receiving increased attention among all aspects of biology because of the unifying themes it helps construct across ecological, evolutionary, developmental, semiochemical, and pest management theory. Insects show a vast array of symbiotic relationships with a wide diversity of microorganisms. These relationships may confer a variety of benefits to the host...

Strategic Research to Enable NASA's Exploration Missions Conference

NASA Technical Reports Server (NTRS)

Nahra, Henry (Compiler)

2004-01-01

Abstracts are presented from a conference sponsored by the NASA Office of Biological and Physical Research and hosted by NASA Glenn Research Center and the National Center for Microgravity Research on Fluids and Combustion, held in Cleveland, Ohio, June 22-23, 2004. Topics pertained to the behavior of processes and materials in microgravity as well as physiological-biological studies and microgravity effects.

Attack on all fronts: functional relationships between aerial and root parasitic plants and their woody hosts and consequences for ecosystems.

PubMed

Bell, T L; Adams, M A

2011-01-01

This review discusses how understanding of functional relationships between parasitic plants and their woody hosts have benefited from a range of approaches to their study. Gross comparisons of nutrient content between infected and uninfected hosts, or parts of hosts, have been widely used to infer basic differences or similarities between hosts and parasites. Coupling of nutrient information with additional evidence of key processes such as transpiration, respiration and photosynthesis has helped elucidate host-parasite relationships and, in some cases, the anatomical nature of their connection and even the physiology of plants in general. For example, detailed analysis of xylem sap from hosts and parasites has increased our understanding of the spatial and temporal movement of solutes within plants. Tracer experiments using natural abundance or enriched application of stable isotopes ((15)N, (13)C, (18)O) have helped us to understand the extent and form of heterotrophy, including the effect of the parasite on growth and functioning of the host (and its converse) as well as environmental effects on the parasite. Nutritional studies of woody hosts and parasites have provided clues to the distribution of parasitic plants and their roles in ecosystems. This review also provides assessment of several corollaries to the host-parasite association.

A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host-Pathogen Interaction Networks.

PubMed

Wu, Chia-Chou; Chen, Bor-Sen

2016-01-01

Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host-pathogen dynamic interaction networks. The consideration of host-pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host-pathogen molecular interaction networks, and consequent inferences of the host-pathogen relationship could be translated into biomedical applications.

The role of HBV-induced autophagy in HBV replication and HBV related-HCC.

PubMed

Xie, Mingjie; Yang, Zhenggang; Liu, Yanning; Zheng, Min

2018-04-27

Hepatitis B virus (HBV) is infecting about 364 million people around the world. It can cause various diseases, such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). However, the present anti-viral treatment in clinics is limited; studies for new therapies are highly desired. Autophagy is a crucial and major catabolic process in the maintenance of normal intracellular homeostasis in host cells. Host cells use this unique process to degrade and recycle long-lived proteins, damaged organelles, and various pathogens for keeping the normal physiological functions. Recently, published studies indicated that HBV can induce autophagy in host cells; this autophagic response is involved in viral replication and pathogenesis. Several viral proteins, such as surface and X proteins, are assumed to be responsible for inducing autophagy in HBV infection. This review briefly summarizes some important mechanisms involved in HBV-induced autophagy and provides a novel perspective on therapies of HBV infection and HBV-related HCC. Copyright © 2017. Published by Elsevier Inc.

Host Competence: An Organismal Trait to Integrate Immunology and Epidemiology.

PubMed

Martin, Lynn B; Burgan, S C; Adelman, James S; Gervasi, Stephanie S

2016-12-01

The new fields of ecological immunology and disease ecology have begun to merge, and the classic fields of immunology and epidemiology are beginning to blend with them. This merger is occurring because the integrative study of host-parasite interactions is providing insights into disease in ways that traditional methods have not. With the advent of new tools, mathematical and technological, we could be on the verge of developing a unified theory of infectious disease, one that supersedes the barriers of jargon and tradition. Here we argue that a cornerstone of any such synthesis will be host competence, the propensity of an individual host to generate new infections in other susceptible hosts. In the last few years, the emergence of systems immunology has led to novel insight into how hosts control or eliminate pathogens. Most such efforts have stopped short of considering transmission and the requisite behaviors of infected individuals that mediate it, and few have explicitly incorporated ecological and evolutionary principles. Ultimately though, we expect that the use of a systems immunology perspective will help link suborganismal processes (i.e., health of hosts and selection on genes) to superorganismal outcomes (i.e., community-level disease dynamics and host-parasite coevolution). Recently, physiological regulatory networks (PRNs) were cast as whole-organism regulatory systems that mediate homeostasis and hence link suborganismal processes with the fitness of individuals. Here, we use the PRN construct to develop a roadmap for studying host competence, taking guidance from systems immunology and evolutionary ecology research. We argue that PRN variation underlies heterogeneity in individual host competence and hence host-parasite dynamics. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

The development of a host potential index and its postharvest application to the spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae)

USDA-ARS?s Scientific Manuscript database

Novel methodology is presented for indexing the relative potential of hosts to function as resources. Results from studies examining host selection, utilization, and physiological development of the organism resourcing the host were combined and quantitatively related via a Host Potential Index (HPI...

A Comparative Analysis of Industrial Escherichia coli K–12 and B Strains in High-Glucose Batch Cultivations on Process-, Transcriptome- and Proteome Level

PubMed Central

Marisch, Karoline; Bayer, Karl; Scharl, Theresa; Mairhofer, Juergen; Krempl, Peter M.; Hummel, Karin; Razzazi-Fazeli, Ebrahim; Striedner, Gerald

2013-01-01

Escherichia coli K–12 and B strains are among the most frequently used bacterial hosts for production of recombinant proteins on an industrial scale. To improve existing processes and to accelerate bioprocess development, we performed a detailed host analysis. We investigated the different behaviors of the E. coli production strains BL21, RV308, and HMS174 in response to high-glucose concentrations. Tightly controlled cultivations were conducted under defined environmental conditions for the in-depth analysis of physiological behavior. In addition to acquisition of standard process parameters, we also used DNA microarray analysis and differential gel electrophoresis (EttanTM DIGE). Batch cultivations showed different yields of the distinct strains for cell dry mass and growth rate, which were highest for BL21. In addition, production of acetate, triggered by excess glucose supply, was much higher for the K–12 strains compared to the B strain. Analysis of transcriptome data showed significant alteration in 347 of 3882 genes common among all three hosts. These differentially expressed genes included, for example, those involved in transport, iron acquisition, and motility. The investigation of proteome patterns additionally revealed a high number of differentially expressed proteins among the investigated hosts. The subsequently selected 38 spots included proteins involved in transport and motility. The results of this comprehensive analysis delivered a full genomic picture of the three investigated strains. Differentially expressed groups for targeted host modification were identified like glucose transport or iron acquisition, enabling potential optimization of strains to improve yield and process quality. Dissimilar growth profiles of the strains confirm different genotypes. Furthermore, distinct transcriptome patterns support differential regulation at the genome level. The identified proteins showed high agreement with the transcriptome data and suggest similar regulation within a host at both levels for the identified groups. Such host attributes need to be considered in future process design and operation. PMID:23950949

A comparative analysis of industrial Escherichia coli K-12 and B strains in high-glucose batch cultivations on process-, transcriptome- and proteome level.

PubMed

Marisch, Karoline; Bayer, Karl; Scharl, Theresa; Mairhofer, Juergen; Krempl, Peter M; Hummel, Karin; Razzazi-Fazeli, Ebrahim; Striedner, Gerald

2013-01-01

Escherichia coli K-12 and B strains are among the most frequently used bacterial hosts for production of recombinant proteins on an industrial scale. To improve existing processes and to accelerate bioprocess development, we performed a detailed host analysis. We investigated the different behaviors of the E. coli production strains BL21, RV308, and HMS174 in response to high-glucose concentrations. Tightly controlled cultivations were conducted under defined environmental conditions for the in-depth analysis of physiological behavior. In addition to acquisition of standard process parameters, we also used DNA microarray analysis and differential gel electrophoresis (Ettan(TM) DIGE). Batch cultivations showed different yields of the distinct strains for cell dry mass and growth rate, which were highest for BL21. In addition, production of acetate, triggered by excess glucose supply, was much higher for the K-12 strains compared to the B strain. Analysis of transcriptome data showed significant alteration in 347 of 3882 genes common among all three hosts. These differentially expressed genes included, for example, those involved in transport, iron acquisition, and motility. The investigation of proteome patterns additionally revealed a high number of differentially expressed proteins among the investigated hosts. The subsequently selected 38 spots included proteins involved in transport and motility. The results of this comprehensive analysis delivered a full genomic picture of the three investigated strains. Differentially expressed groups for targeted host modification were identified like glucose transport or iron acquisition, enabling potential optimization of strains to improve yield and process quality. Dissimilar growth profiles of the strains confirm different genotypes. Furthermore, distinct transcriptome patterns support differential regulation at the genome level. The identified proteins showed high agreement with the transcriptome data and suggest similar regulation within a host at both levels for the identified groups. Such host attributes need to be considered in future process design and operation.

Transposable Elements Re-Wire and Fine-Tune the Transcriptome

PubMed Central

Cowley, Michael; Oakey, Rebecca J.

2013-01-01

What good are transposable elements (TEs)? Although their activity can be harmful to host genomes and can cause disease, they nevertheless represent an important source of genetic variation that has helped shape genomes. In this review, we examine the impact of TEs, collectively referred to as the mobilome, on the transcriptome. We explore how TEs—particularly retrotransposons—contribute to transcript diversity and consider their potential significance as a source of small RNAs that regulate host gene transcription. We also discuss a critical role for the mobilome in engineering transcriptional networks, permitting coordinated gene expression, and facilitating the evolution of novel physiological processes. PMID:23358118

Gut Microbiota: Modulation of Host Physiology in Obesity

PubMed Central

Allen, Jacob M.; Mailing, Lucy J.; Kashyap, Purna C.; Woods, Jeffrey A.

2016-01-01

Many factors are involved in weight gain and metabolic disturbances associated with obesity. The gut microbiota has been of particular interest in recent years, since both human and animal studies have increased our understanding of the delicate symbiosis between the trillions of microbes that reside in the GI tract and the host. It has been suggested that disruption of this mutual tolerance may play a significant role in modulating host physiology during obesity. Environmental influences such as diet, exercise, and early life exposures can significantly impact the composition of the microbiota, and this dysbiosis can in turn lead to increased host adiposity via a number of different mechanisms. The ability of the microbiota to regulate host fat deposition, metabolism, and immune function makes it an attractive target for achieving sustained weight loss. PMID:27511459

At the Frontier; RXLR Effectors Crossing the Phytophthora-Host Interface.

PubMed

Bouwmeester, Klaas; Meijer, Harold J G; Govers, Francine

2011-01-01

Plants are constantly beset by pathogenic organisms. To successfully infect their hosts, plant pathogens secrete effector proteins, many of which are translocated to the inside of the host cell where they manipulate normal physiological processes and undermine host defense. The way by which effectors cross the frontier to reach the inside of the host cell varies among different classes of pathogens. For oomycete plant pathogens - like the potato late blight pathogen Phytophthora infestans - it has been shown that effector translocation to the host cell cytoplasm is dependent on conserved amino acid motifs that are present in the N-terminal part of effector proteins. One of these motifs, known as the RXLR motif, has a strong resemblance with a host translocation motif found in effectors secreted by Plasmodium species. These malaria parasites, that reside inside specialized vacuoles in red blood cells, make use of a specific protein translocation complex to export effectors from the vacuole into the red blood cell. Whether or not also oomycete RXLR effectors require a translocation complex to cross the frontier is still under investigation. For one P. infestans RXLR effector named IPI-O we have found a potential host target that could play a role in establishing the first contact between this effector and the host cell. This membrane spanning lectin receptor kinase, LecRK-I.9, interacts with IPI-O via the tripeptide RGD that overlaps with the RXLR motif. In animals, RGD is a well-known cell adhesion motif; it binds to integrins, which are membrane receptors that regulate many cellular processes and which can be hijacked by pathogens for either effector translocation or pathogen entry into host cells.

Subtle effect of Xenos vesparum (Xenidae, Strepsiptera) on the reproductive apparatus of its male host: Parasite or parasitoid?

PubMed

Beani, L; Marchini, D; Cappa, F; Petrocelli, I; Gottardo, M; Manfredini, F; Giusti, F; Dallai, R

2017-08-01

Parasitic castration is an adaptive strategy where parasites usurp the hosts' reproductive physiology to complete their life cycle. The alterations in the host traits vary in their magnitude, from subtle changes in the host morpho-physiology and behaviour to the production of complex aberrant phenotypes, which often depend on the host gender. The strepsipteran macroparasite Xenos vesparum induces dramatic behavioural and physiological changes in its female host, the paper wasp Polistes dominula, while its effect on the male phenotype is largely unknown. In this study we investigated how a single X. vesparum parasite influences the functional morphology of P. dominula male reproductive apparatus. We performed morphometry and ultrastructure characterization of corpora allata, testes, seminal vesicles and accessory glands in parasitized and unparasitized males, and also in young and old males to control for the effect of age on the natural deterioration of these organs. Our results show that age significantly affects the development of male reproductive apparatus. A low parasite load - one parasite per host is the common prevalence in the field - has only a marginal impact on the reproductive morphology of P. dominula males, affecting quantitatively but not qualitatively the protein content of male accessory glands. Thus, in male P. dominula wasps, X. vesparum appears to behave as a true "parasite", in clear opposition to the role of "parasitoid" that it takes in female hosts where castration causes the reproductive death. Copyright © 2017 Elsevier Ltd. All rights reserved.

Three-Dimensional Rotating Wall Vessel-Derived Cell Culture Models for Studying Virus-Host Interactions

PubMed Central

Gardner, Jameson K.; Herbst-Kralovetz, Melissa M.

2016-01-01

The key to better understanding complex virus-host interactions is the utilization of robust three-dimensional (3D) human cell cultures that effectively recapitulate native tissue architecture and model the microenvironment. A lack of physiologically-relevant animal models for many viruses has limited the elucidation of factors that influence viral pathogenesis and of complex host immune mechanisms. Conventional monolayer cell cultures may support viral infection, but are unable to form the tissue structures and complex microenvironments that mimic host physiology and, therefore, limiting their translational utility. The rotating wall vessel (RWV) bioreactor was designed by the National Aeronautics and Space Administration (NASA) to model microgravity and was later found to more accurately reproduce features of human tissue in vivo. Cells grown in RWV bioreactors develop in a low fluid-shear environment, which enables cells to form complex 3D tissue-like aggregates. A wide variety of human tissues (from neuronal to vaginal tissue) have been grown in RWV bioreactors and have been shown to support productive viral infection and physiological meaningful host responses. The in vivo-like characteristics and cellular features of the human 3D RWV-derived aggregates make them ideal model systems to effectively recapitulate pathophysiology and host responses necessary to conduct rigorous basic science, preclinical and translational studies. PMID:27834891

Antimicrobial growth promoters modulate host responses in mice with a defined intestinal microbiota

PubMed Central

Brown, Kirsty; Zaytsoff, Sarah J. M.; Uwiera, Richard R. E.; Inglis, G. Douglas

2016-01-01

Antibiotics can promote growth in livestock (antimicrobial growth promoters, AGPs), however lack of knowledge regarding mechanisms has hampered the development of effective non-antibiotic alternatives. Antibiotics affect eukaryotic cells at therapeutic concentrations, yet effects of AGPs on host physiology are relatively understudied, partially due to the complexity of host-microorganism interactions within the gastrointestinal tract. To determine the direct effects of AGPs on the host, we generated Altered Schaedler Flora (ASF) mice, and administered chlortetracycline (CTC) and tylosin phosphate (TYL) in feed. Mice were challenged with Citrobacter rodentium to determine how AGPs alter host responses to physiological stress. Although CTC and TYL had inconsistent effects on the ASF taxa, AGPs protected mice from weight loss following C. rodentium inoculation. Mice treated with either CTC or TYL had lower expression of βd1 and Il17a in the intestine and had a robust induction of Il17a and Il10. Furthermore, AGP administration resulted in a lower hepatic expression of acute phase proteins (Saa1, Hp, and Cp) in liver tissue, and ameliorated C. rodentium-induced reductions in the expression of genes involved in lipogenesis (Hmgcl and Fabp1). Collectively, this indicates that AGPs directly affect host physiology, and highlights important considerations in the development of non-antibiotic alternatives. PMID:27929072

Human Intestinal Enteroids: a New Model To Study Human Rotavirus Infection, Host Restriction, and Pathophysiology

PubMed Central

Saxena, Kapil; Blutt, Sarah E.; Ettayebi, Khalil; Zeng, Xi-Lei; Broughman, James R.; Crawford, Sue E.; Karandikar, Umesh C.; Sastri, Narayan P.; Conner, Margaret E.; Opekun, Antone R.; Graham, David Y.; Qureshi, Waqar; Sherman, Vadim; Foulke-Abel, Jennifer; In, Julie; Kovbasnjuk, Olga; Zachos, Nicholas C.; Donowitz, Mark

2015-01-01

ABSTRACT Human gastrointestinal tract research is limited by the paucity of in vitro intestinal cell models that recapitulate the cellular diversity and complex functions of human physiology and disease pathology. Human intestinal enteroid (HIE) cultures contain multiple intestinal epithelial cell types that comprise the intestinal epithelium (enterocytes and goblet, enteroendocrine, and Paneth cells) and are physiologically active based on responses to agonists. We evaluated these nontransformed, three-dimensional HIE cultures as models for pathogenic infections in the small intestine by examining whether HIEs from different regions of the small intestine from different patients are susceptible to human rotavirus (HRV) infection. Little is known about HRVs, as they generally replicate poorly in transformed cell lines, and host range restriction prevents their replication in many animal models, whereas many animal rotaviruses (ARVs) exhibit a broader host range and replicate in mice. Using HRVs, including the Rotarix RV1 vaccine strain, and ARVs, we evaluated host susceptibility, virus production, and cellular responses of HIEs. HRVs infect at higher rates and grow to higher titers than do ARVs. HRVs infect differentiated enterocytes and enteroendocrine cells, and viroplasms and lipid droplets are induced. Heterogeneity in replication was seen in HIEs from different patients. HRV infection and RV enterotoxin treatment of HIEs caused physiological lumenal expansion detected by time-lapse microscopy, recapitulating one of the hallmarks of rotavirus-induced diarrhea. These results demonstrate that HIEs are a novel pathophysiological model that will allow the study of HRV biology, including host restriction, cell type restriction, and virus-induced fluid secretion. IMPORTANCE Our research establishes HIEs as nontransformed cell culture models to understand human intestinal physiology and pathophysiology and the epithelial response, including host restriction of gastrointestinal infections such as HRV infection. HRVs remain a major worldwide cause of diarrhea-associated morbidity and mortality in children ≤5 years of age. Current in vitro models of rotavirus infection rely primarily on the use of animal rotaviruses because HRV growth is limited in most transformed cell lines and animal models. We demonstrate that HIEs are novel, cellularly diverse, and physiologically relevant epithelial cell cultures that recapitulate in vivo properties of HRV infection. HIEs will allow the study of HRV biology, including human host-pathogen and live, attenuated vaccine interactions; host and cell type restriction; virus-induced fluid secretion; cell-cell communication within the epithelium; and the epithelial response to infection in cultures from genetically diverse individuals. Finally, drug therapies to prevent/treat diarrheal disease can be tested in these physiologically active cultures. PMID:26446608

Transcriptomic Profiling of High-Density Giardia Foci Encysting in the Murine Proximal Intestine.

PubMed

Pham, Jonathan K; Nosala, Christopher; Scott, Erica Y; Nguyen, Kristofer F; Hagen, Kari D; Starcevich, Hannah N; Dawson, Scott C

2017-01-01

Giardia is a highly prevalent, understudied protistan parasite causing significant diarrheal disease worldwide. Its life cycle consists of two stages: infectious cysts ingested from contaminated food or water sources, and motile trophozoites that colonize and attach to the gut epithelium, later encysting to form new cysts that are excreted into the environment. Current understanding of parasite physiology in the host is largely inferred from transcriptomic studies using Giardia grown axenically or in co-culture with mammalian cell lines. The dearth of information about the diversity of host-parasite interactions occurring within distinct regions of the gastrointestinal tract has been exacerbated by a lack of methods to directly and non-invasively interrogate disease progression and parasite physiology in live animal hosts. By visualizing Giardia infections in the mouse gastrointestinal tract using bioluminescent imaging (BLI) of tagged parasites, we recently showed that parasites colonize the gut in high-density foci. Encystation is initiated in these foci throughout the entire course of infection, yet how the physiology of parasites within high-density foci in the host gut differs from that of cells in laboratory culture is unclear. Here we use BLI to precisely select parasite samples from high-density foci in the proximal intestine to interrogate in vivo Giardia gene expression in the host. Relative to axenic culture, we noted significantly higher expression (>10-fold) of oxidative stress, membrane transporter, and metabolic and structural genes associated with encystation in the high-density foci. These differences in gene expression within parasite foci in the host may reflect physiological changes associated with high-density growth in localized regions of the gut. We also identified and verified six novel cyst-specific proteins, including new components of the cyst wall that were highly expressed in these foci. Our in vivo transcriptome data support an emerging view that parasites encyst early in localized regions in the gut, possibly as a consequence of nutrient limitation, and also impact local metabolism and physiology.

Transcriptomic Profiling of High-Density Giardia Foci Encysting in the Murine Proximal Intestine

PubMed Central

Pham, Jonathan K.; Nosala, Christopher; Scott, Erica Y.; Nguyen, Kristofer F.; Hagen, Kari D.; Starcevich, Hannah N.; Dawson, Scott C.

2017-01-01

Giardia is a highly prevalent, understudied protistan parasite causing significant diarrheal disease worldwide. Its life cycle consists of two stages: infectious cysts ingested from contaminated food or water sources, and motile trophozoites that colonize and attach to the gut epithelium, later encysting to form new cysts that are excreted into the environment. Current understanding of parasite physiology in the host is largely inferred from transcriptomic studies using Giardia grown axenically or in co-culture with mammalian cell lines. The dearth of information about the diversity of host-parasite interactions occurring within distinct regions of the gastrointestinal tract has been exacerbated by a lack of methods to directly and non-invasively interrogate disease progression and parasite physiology in live animal hosts. By visualizing Giardia infections in the mouse gastrointestinal tract using bioluminescent imaging (BLI) of tagged parasites, we recently showed that parasites colonize the gut in high-density foci. Encystation is initiated in these foci throughout the entire course of infection, yet how the physiology of parasites within high-density foci in the host gut differs from that of cells in laboratory culture is unclear. Here we use BLI to precisely select parasite samples from high-density foci in the proximal intestine to interrogate in vivo Giardia gene expression in the host. Relative to axenic culture, we noted significantly higher expression (>10-fold) of oxidative stress, membrane transporter, and metabolic and structural genes associated with encystation in the high-density foci. These differences in gene expression within parasite foci in the host may reflect physiological changes associated with high-density growth in localized regions of the gut. We also identified and verified six novel cyst-specific proteins, including new components of the cyst wall that were highly expressed in these foci. Our in vivo transcriptome data support an emerging view that parasites encyst early in localized regions in the gut, possibly as a consequence of nutrient limitation, and also impact local metabolism and physiology. PMID:28620589

Contrasting physiological plasticity in response to environmental stress within different cnidarians and their respective symbionts

NASA Astrophysics Data System (ADS)

Hoadley, Kenneth D.; Pettay, Daniel. T.; Dodge, Danielle; Warner, Mark E.

2016-06-01

Given concerns surrounding coral bleaching and ocean acidification, there is renewed interest in characterizing the physiological differences across the multiple host-algal symbiont combinations commonly found on coral reefs. Elevated temperature and CO2 were used to compare physiological responses within the scleractinian corals Montipora hirsuta ( Symbiodinium C15) and Pocillopora damicornis ( Symbiodinium D1), as well as the corallimorph (a non-calcifying anthozoan closely related to scleractinians) Discosoma nummiforme ( Symbiodinium C3). Several physiological proxies were affected more by temperature than CO2, including photochemistry, algal number and cellular chlorophyll a. Marked differences in symbiont number, chlorophyll and volume contributed to distinctive patterns of chlorophyll absorption among these animals. In contrast, carbon fixation either did not change or increased under elevated temperature. Also, the rate of photosynthetically fixed carbon translocated to each host did not change, and the percent of carbon translocated to the host increased in the corallimorph. Comparing all data revealed a significant negative correlation between photosynthetic rate and symbiont density that corroborates previous hypotheses about carbon limitation in these symbioses. The ratio of symbiont-normalized photosynthetic rate relative to the rate of symbiont-normalized carbon translocation (P:T) was compared in these organisms as well as the anemone, Exaiptasia pallida hosting Symbiodinium minutum, and revealed a P:T close to unity ( D. nummiforme) to a range of 2.0-4.5, with the lowest carbon translocation in the sea anemone. Major differences in the thermal responses across these organisms provide further evidence of a range of acclimation potential and physiological plasticity that highlights the need for continued study of these symbioses across a larger group of host taxa.

Empirical evaluation of neutral interactions in host-parasite networks.

PubMed

Canard, E F; Mouquet, N; Mouillot, D; Stanko, M; Miklisova, D; Gravel, D

2014-04-01

While niche-based processes have been invoked extensively to explain the structure of interaction networks, recent studies propose that neutrality could also be of great importance. Under the neutral hypothesis, network structure would simply emerge from random encounters between individuals and thus would be directly linked to species abundance. We investigated the impact of species abundance distributions on qualitative and quantitative metrics of 113 host-parasite networks. We analyzed the concordance between neutral expectations and empirical observations at interaction, species, and network levels. We found that species abundance accurately predicts network metrics at all levels. Despite host-parasite systems being constrained by physiology and immunology, our results suggest that neutrality could also explain, at least partially, their structure. We hypothesize that trait matching would determine potential interactions between species, while abundance would determine their realization.

A theoretical individual-based model of Brown Ring Disease in Manila clams, Venerupis philippinarum

NASA Astrophysics Data System (ADS)

Paillard, Christine; Jean, Fred; Ford, Susan E.; Powell, Eric N.; Klinck, John M.; Hofmann, Eileen E.; Flye-Sainte-Marie, Jonathan

2014-08-01

An individual-based mathematical model was developed to investigate the biological and environmental interactions that influence the prevalence and intensity of Brown Ring Disease (BRD), a disease, caused by the bacterial pathogen, Vibrio tapetis, in the Manila clam (Venerupis (= Tapes, = Ruditapes) philippinarum). V. tapetis acts as an external microparasite, adhering at the surface of the mantle edge and its secretion, the periostracal lamina, causing the symptomatic brown deposit. Brown Ring Disease is atypical in that it leaves a shell scar that provides a unique tool for diagnosis of either live or dead clams. The model was formulated using laboratory and field measurements of BRD development in Manila clams, physiological responses of the clam to the pathogen, and the physiology of V. tapetis, as well as theoretical understanding of bacterial disease progression in marine shellfish. The simulation results obtained for an individual Manila clam were expanded to cohorts and populations using a probability distribution that prescribed a range of variability for parameters in a three dimensional framework; assimilation rate, clam hemocyte activity rate (the number of bacteria ingested per hemocyte per day), and clam calcification rate (a measure of the ability to recover by covering over the symptomatic brown ring deposit), which sensitivity studies indicated to be processes important in determining BRD prevalence and intensity. This approach allows concurrent simulation of individuals with a variety of different physiological capabilities (phenotypes) and hence by implication differing genotypic composition. Different combinations of the three variables provide robust estimates for the fate of individuals with particular characteristics in a population that consists of mixtures of all possible combinations. The BRD model was implemented using environmental observations from sites in Brittany, France, where Manila clams routinely exhibit BRD signs. The simulated annual cycle of BRD prevalence and intensity agrees with observed disease cycles in cultured clam populations from this region, with maximum disease prevalence and intensity occurring from December to April. Sensitivity analyses of modeled physiological processes showed that the level of hemocyte activity is the primary intrinsic determinant of recovery of infected clams. Simulations designed to investigate environmental effects on BRD suggested that the outcome of the host-parasite interaction is dependent on food supply (high values being favorable for the host) and temperature. Results of simulations illustrate the complex interaction of temperature effects on propagation and viability of the bacterium, on the phagocytic activity of the hemocytes, and on other physiological processes of the host clam. Simulations using 1 °C and 2 °C increases in temperature generally favored disease development, indicating that climate warming might favor the spread of BRD.

Host tree phenology affects vascular epiphytes at the physiological, demographic and community level

PubMed Central

Einzmann, Helena J. R.; Beyschlag, Joachim; Hofhansl, Florian; Wanek, Wolfgang; Zotz, Gerhard

2015-01-01

The processes that govern diverse tropical plant communities have rarely been studied in life forms other than trees. Structurally dependent vascular epiphytes, a major part of tropical biodiversity, grow in a three-dimensional matrix defined by their hosts, but trees differ in their architecture, bark structure/chemistry and leaf phenology. We hypothesized that the resulting seasonal differences in microclimatic conditions in evergreen vs. deciduous trees would affect epiphytes at different levels, from organ physiology to community structure. We studied the influence of tree leaf phenology on vascular epiphytes on the Island of Barro Colorado, Panama. Five tree species were selected, which were deciduous, semi-deciduous or evergreen. The crowns of drought-deciduous trees, characterized by sunnier and drier microclimates, hosted fewer individuals and less diverse epiphyte assemblages. Differences were also observed at a functional level, e.g. epiphyte assemblages in deciduous trees had larger proportions of Crassulacean acid metabolism species and individuals. At the population level a drier microclimate was associated with lower individual growth and survival in a xerophytic fern. Some species also showed, as expected, lower specific leaf area and higher δ13C values when growing in deciduous trees compared with evergreen trees. As hypothesized, host tree leaf phenology influences vascular epiphytes at different levels. Our results suggest a cascading effect of tree composition and associated differences in tree phenology on the diversity and functioning of epiphyte communities in tropical lowland forests. PMID:25392188

Patterns of host adaptation in Frankliniella occidentalis among vegetable crops

USDA-ARS?s Scientific Manuscript database

The current study examined the variation in life table characteristics, and physiological, biochemical, and molecular bases of western flower thrips, Frankliniella occidentalis (Pergande) host adaptation patterns. The main objective was to determine whether host availability affects insect preferenc...

The endoparasitoid, Cotesia vestalis, regulates host physiology by reprogramming the neuropeptide transcriptional network

USDA-ARS?s Scientific Manuscript database

Endoparasitoids develop inside another insect; success depends on regulating host immunity and development by maternal factors injected into hosts during oviposition, including venom, polydnaviruses and teratocytes. Although prior results provide insights into parasitism-induced immunosuppression, l...

Host-derived viral transporter protein for nitrogen uptake in infected marine phytoplankton

PubMed Central

Chambouvet, Aurélie; Milner, David S.; Attah, Victoria; Terrado, Ramón; Lovejoy, Connie; Moreau, Hervé; Derelle, Évelyne; Richards, Thomas A.

2017-01-01

Phytoplankton community structure is shaped by both bottom–up factors, such as nutrient availability, and top–down processes, such as predation. Here we show that marine viruses can blur these distinctions, being able to amend how host cells acquire nutrients from their environment while also predating and lysing their algal hosts. Viral genomes often encode genes derived from their host. These genes may allow the virus to manipulate host metabolism to improve viral fitness. We identify in the genome of a phytoplankton virus, which infects the small green alga Ostreococcus tauri, a host-derived ammonium transporter. This gene is transcribed during infection and when expressed in yeast mutants the viral protein is located to the plasma membrane and rescues growth when cultured with ammonium as the sole nitrogen source. We also show that viral infection alters the nature of nitrogen compound uptake of host cells, by both increasing substrate affinity and allowing the host to access diverse nitrogen sources. This is important because the availability of nitrogen often limits phytoplankton growth. Collectively, these data show that a virus can acquire genes encoding nutrient transporters from a host genome and that expression of the viral gene can alter the nutrient uptake behavior of host cells. These results have implications for understanding how viruses manipulate the physiology and ecology of phytoplankton, influence marine nutrient cycles, and act as vectors for horizontal gene transfer. PMID:28827361

NMR-Based Metabonomic Analysis of Physiological Responses to Starvation and Refeeding in the Rat.

PubMed

Serrano-Contreras, José I; García-Pérez, Isabel; Meléndez-Camargo, María E; Zepeda, L Gerardo

2016-09-02

Starvation is a postabsorptive condition derived from a limitation on food resources by external factors. Energy homeostasis is maintained under this condition by using sources other than glucose via adaptive mechanisms. After refeeding, when food is available, other adaptive processes are linked to energy balance. However, less has been reported about the physiological mechanisms present as a result of these conditions, considering the rat as a supraorganism. Metabolic profiling using (1)H nuclear magnetic resonance spectroscopy was used to characterize the physiological metabolic differences in urine specimens collected under starved, refed, and recovered conditions. In addition, because starvation induced lack of faecal production and not all animals produced faeces during refeeding, 24 h pooled faecal water samples were also analyzed. Urinary metabolites upregulated by starvation included 2-butanamidoacetate, 3-hydroxyisovalerate, ketoleucine, methylmalonate, p-cresyl glucuronide, p-cresyl sulfate, phenylacetylglycine, pseudouridine, creatinine, taurine, and N-acetyl glycoprotein, which were related to renal and skeletal muscle function, β-oxidation, turnover of proteins and RNA, and host-microbial interactions. Food-derived metabolites, including gut microbial cometabolites, and tricarboxylic acid cycle intermediates were upregulated under refed and recovered conditions, which characterized anabolic urinary metabotypes. The upregulation of creatine and pantothenate indicated an absorptive state after refeeding. Fecal short chain fatty acids, 3-(3-hydroxyphenyl)propionate, lactate, and acetoin provided additional information about the combinatorial metabolism between the host and gut microbiota. This investigation contributes to allow a deeper understanding of physiological responses associated with starvation and refeeding.

Heritable Bovine Rumen Bacteria Are Phylogenetically Related and Correlated with the Cow’s Capacity To Harvest Energy from Its Feed

PubMed Central

Sasson, Goor; Kruger Ben-Shabat, Sheerli; Seroussi, Eyal; Doron-Faigenboim, Adi; Shterzer, Naama; Yaacoby, Shamay; Berg Miller, Margret E.; White, Bryan A.; Halperin, Eran

2017-01-01

ABSTRACT Ruminants sustain a long-lasting obligatory relationship with their rumen microbiome dating back 50 million years. In this unique host-microbiome relationship, the host’s ability to digest its feed is completely dependent on its coevolved microbiome. This extraordinary alliance raises questions regarding the dependent relationship between ruminants’ genetics and physiology and the rumen microbiome structure, composition, and metabolism. To elucidate this relationship, we examined the association of host genetics with the phylogenetic and functional composition of the rumen microbiome. We accomplished this by studying a population of 78 Holstein-Friesian dairy cows, using a combination of rumen microbiota data and other phenotypes from each animal with genotypic data from a subset of 47 animals. We identified 22 operational taxonomic units (OTUs) whose abundances were associated with rumen metabolic traits and host physiological traits and which showed measurable heritability. The abundance patterns of these microbes can explain high proportions of variance in rumen metabolism and many of the host physiological attributes such as its energy-harvesting efficiency. Interestingly, these OTUs shared higher phylogenetic similarity between themselves than expected by chance, suggesting occupation of a specific ecological niche within the rumen ecosystem. The findings presented here suggest that ruminant genetics and physiology are correlated with microbiome structure and that host genetics may shape the microbiome landscape by enriching for phylogenetically related taxa that may occupy a unique niche. PMID:28811339

The Metronome of Symbiosis: Interactions Between Microbes and the Host Circadian Clock.

PubMed

Heath-Heckman, Elizabeth A C

2016-11-01

The entrainment of circadian rhythms, physiological cycles with a period of about 24 h, is regulated by a variety of mechanisms, including nonvisual photoreception. While circadian rhythms have been shown to be integral to many processes in multicellular organisms, including immune regulation, the effect of circadian rhythms on symbiosis, or host-microbe interactions, has only recently begun to be studied. This review summarizes recent work in the interactions of both pathogenic and mutualistic associations with host and symbiont circadian rhythms, focusing specifically on three mutualistic systems in which this phenomenon has been best studied. One important theme taken from these studies is the fact that mutualisms are profoundly affected by the circadian rhythms of the host, but that the microbial symbionts in these associations can, in turn, manipulate host rhythms. The interplay between circadian rhythms and symbiosis is a promising new field with effects that should be kept in mind when designing future studies across biology. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

White-nose syndrome initiates a cascade of physiologic disturbances in the hibernating bat host.

PubMed

Verant, Michelle L; Meteyer, Carol U; Speakman, John R; Cryan, Paul M; Lorch, Jeffrey M; Blehert, David S

2014-12-09

The physiological effects of white-nose syndrome (WNS) in hibernating bats and ultimate causes of mortality from infection with Pseudogymnoascus (formerly Geomyces) destructans are not fully understood. Increased frequency of arousal from torpor described among hibernating bats with late-stage WNS is thought to accelerate depletion of fat reserves, but the physiological mechanisms that lead to these alterations in hibernation behavior have not been elucidated. We used the doubly labeled water (DLW) method and clinical chemistry to evaluate energy use, body composition changes, and blood chemistry perturbations in hibernating little brown bats (Myotis lucifugus) experimentally infected with P. destructans to better understand the physiological processes that underlie mortality from WNS. These data indicated that fat energy utilization, as demonstrated by changes in body composition, was two-fold higher for bats with WNS compared to negative controls. These differences were apparent in early stages of infection when torpor-arousal patterns were equivalent between infected and non-infected animals, suggesting that P. destructans has complex physiological impacts on its host prior to onset of clinical signs indicative of late-stage infections. Additionally, bats with mild to moderate skin lesions associated with early-stage WNS demonstrated a chronic respiratory acidosis characterized by significantly elevated dissolved carbon dioxide, acidemia, and elevated bicarbonate. Potassium concentrations were also significantly higher among infected bats, but sodium, chloride, and other hydration parameters were equivalent to controls. Integrating these novel findings on the physiological changes that occur in early-stage WNS with those previously documented in late-stage infections, we propose a multi-stage disease progression model that mechanistically describes the pathologic and physiologic effects underlying mortality of WNS in hibernating bats. This model identifies testable hypotheses for better understanding this disease, knowledge that will be critical for defining effective disease mitigation strategies aimed at reducing morbidity and mortality that results from WNS.

Mapping the microbiome of Ictalurid catfish: tissue and species-specific community composition

USDA-ARS?s Scientific Manuscript database

Host mucosal immunity is regulated by the complex interplay between environmental factors, host genetics, and commensal and pathogen dynamics. Microbial imbalances due to physiological stressors, changes in nutrition, and/or antibiotic application can potentiate over-exuberant host immune responses ...

Attractants for ACP trapping technology: Challenges, status, and opportunities

USDA-ARS?s Scientific Manuscript database

Psyllid host searching behavior is complex and sophisticated. It can be influenced by host species, growth stage, and physiological condition, psyllid gender and mating status, behavioral plasticity, usurpation by phytopathogens of host aromas, and psyllid-induced emission of foliar volatiles. Asian...

Wolbachia infection in Aedes aegypti mosquitoes alters blood meal excretion and delays oviposition without affecting trypsin activity.

PubMed

Pimenta de Oliveira, Sofia; Dantas de Oliveira, Caroline; Viana Sant'Anna, Mauricio Roberto; Carneiro Dutra, Heverton Leandro; Caragata, Eric Pearce; Moreira, Luciano Andrade

2017-08-01

Blood feeding in Aedes aegypti is essential for reproduction, but also permits the mosquito to act as a vector for key human pathogens such as the Zika and dengue viruses. Wolbachia pipientis is an endosymbiotic bacterium that can manipulate the biology of Aedes aegypti mosquitoes, making them less competent hosts for many pathogens. Yet while Wolbachia affects other aspects of host physiology, it is unclear whether it influences physiological processes associated with blood meal digestion. To that end, we examined the effects of wMel Wolbachia infection in Ae. aegypti, on survival post-blood feeding, blood meal excretion, rate of oviposition, expression levels of key genes involved in oogenesis, and activity levels of trypsin blood digestion enzymes. We observed that wMel infection altered the rate and duration of blood meal excretion, delayed the onset of oviposition and was associated with a greater number of eggs being laid later. wMel-infected Ae. aegypti also had lower levels of key yolk protein precursor genes necessary for oogenesis. However, all of these effects occurred without a change in trypsin activity. These results suggest that Wolbachia infection may disrupt normal metabolic processes associated with blood feeding and reproduction in Ae. aegypti. Copyright © 2017 Elsevier Ltd. All rights reserved.

Proteomics Indicators of the Rapidly Shifting Physiology from Whole Mountain Pine Beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae), Adults during Early Host Colonization

PubMed Central

Pitt, Caitlin; Robert, Jeanne A.; Bonnett, Tiffany R.; Keeling, Christopher I.; Bohlmann, Jörg; Huber, Dezene P. W.

2014-01-01

We developed proteome profiles for host colonizing mountain pine beetle adults, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae). Adult insects were fed in pairs on fresh host lodgepole pine, Pinus contorta Dougl. ex Loud, phloem tissue. The proteomes of fed individuals were monitored using iTRAQ and compared to those of starved beetles, revealing 757 and 739 expressed proteins in females and males, respectively, for which quantitative information was obtained. Overall functional category distributions were similar for males and females, with the majority of proteins falling under carbohydrate metabolism (glycolysis, gluconeogenesis, citric acid cycle), structure (cuticle, muscle, cytoskeleton), and protein and amino acid metabolism. Females had 23 proteins with levels that changed significantly with feeding (p<0.05, FDR<0.20), including chaperones and enzymes required for vitellogenesis. In males, levels of 29 proteins changed significantly with feeding (p<0.05, FDR<0.20), including chaperones as well as motor proteins. Only two proteins, both chaperones, exhibited a significant change in both females and males with feeding. Proteins with differential accumulation patterns in females exhibited higher fold changes with feeding than did those in males. This difference may be due to major and rapid physiological changes occurring in females upon finding a host tree during the physiological shift from dispersal to reproduction. The significant accumulation of chaperone proteins, a cytochrome P450, and a glutathione S-transferase, indicate secondary metabolite-induced stress physiology related to chemical detoxification during early host colonization. The females' activation of vitellogenin only after encountering a host indicates deliberate partitioning of resources and a balancing of the needs of dispersal and reproduction. PMID:25360753

Proteomics indicators of the rapidly shifting physiology from whole mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae), adults during early host colonization.

PubMed

Pitt, Caitlin; Robert, Jeanne A; Bonnett, Tiffany R; Keeling, Christopher I; Bohlmann, Jörg; Huber, Dezene P W

2014-01-01

We developed proteome profiles for host colonizing mountain pine beetle adults, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae). Adult insects were fed in pairs on fresh host lodgepole pine, Pinus contorta Dougl. ex Loud, phloem tissue. The proteomes of fed individuals were monitored using iTRAQ and compared to those of starved beetles, revealing 757 and 739 expressed proteins in females and males, respectively, for which quantitative information was obtained. Overall functional category distributions were similar for males and females, with the majority of proteins falling under carbohydrate metabolism (glycolysis, gluconeogenesis, citric acid cycle), structure (cuticle, muscle, cytoskeleton), and protein and amino acid metabolism. Females had 23 proteins with levels that changed significantly with feeding (p<0.05, FDR<0.20), including chaperones and enzymes required for vitellogenesis. In males, levels of 29 proteins changed significantly with feeding (p<0.05, FDR<0.20), including chaperones as well as motor proteins. Only two proteins, both chaperones, exhibited a significant change in both females and males with feeding. Proteins with differential accumulation patterns in females exhibited higher fold changes with feeding than did those in males. This difference may be due to major and rapid physiological changes occurring in females upon finding a host tree during the physiological shift from dispersal to reproduction. The significant accumulation of chaperone proteins, a cytochrome P450, and a glutathione S-transferase, indicate secondary metabolite-induced stress physiology related to chemical detoxification during early host colonization. The females' activation of vitellogenin only after encountering a host indicates deliberate partitioning of resources and a balancing of the needs of dispersal and reproduction.

WASP-ASSOCIATED FACTORS ACT IN INTERSPECIES COMPETITION DURING MULTIPARASITISM.

PubMed

Magdaraog, Peter M; Tanaka, Toshiharu; Harvey, Jeffrey A

2016-06-01

Coexistence or displacement of parasitoids in hosts during intrinsic competitive interactions between different parasitoid species (multiparasitism) may depend on their life history traits and behavior. Intense competition for possession of hosts may lead to the elimination of the inferior competitor through physical attack and/or physiological suppression. However, the mechanisms of physiological suppression during multiparasitism remain unclear. Previous work has shown that first instar larvae of the solitary endoparasitoid Meteorus pulchricornis possess well-developed mandibles that are used to kill competitors. Two gregarious endoparasitoids, Cotesia kariyai and C. rufricus, share host resources especially when the time gap of oviposition is short. Here, we investigated the physiological influence of wasp-regulatory factors of the three endoparasitoids, M. pulchricornis, C. kariyai, and C. ruficrus, in their common host Mythimna separata. We found that MpVLP alone (or with venom) deleteriously affected the development of the two gregarious species. Similarly, CkPDV plus venom had toxic effect on M. pulchricornis eggs and immature larvae, although they were not harmful to immature stages of C. ruficrus. Cotesia kariyai and C. ruficrus were able to coexist mainly through the expression of regulatory factors and both could successfully emerge from a multiparasitized host. The injection of CkPDV plus venom after oviposition in L5 host larvae facilitated C. ruficrus development and increased the rate of successful parasitism from 9% to 62%. This suggests that the two gregarious parasitoid wasps exhibit strong phylogenetic affinity, favoring their coexistence and success in multiparasitized hosts. © 2016 Wiley Periodicals, Inc.

Antibiotic-Induced Changes in the Intestinal Microbiota and Disease

PubMed Central

Becattini, Simone; Taur, Ying; Pamer, Eric G.

2016-01-01

The gut microbiota is a key player in many physiological and pathological processes occurring in humans. Recent investigations suggest that the efficacy of some clinical approaches depends on the action of commensal bacteria. Antibiotics are invaluable weapons to fight infectious diseases. However, by altering the composition and functions of the microbiota, they can also produce long-lasting deleterious effects for the host. The emergence of multidrug-resistant pathogens raises concerns about the common, and at times inappropriate, use of antimicrobial agents. Here we review the most recently discovered connections between host pathophysiology, microbiota, and antibiotics highlighting technological platforms, mechanistic insights, and clinical strategies to enhance resistance to diseases by preserving the beneficial functions of the microbiota. PMID:27178527

Host Coenzyme Q Redox State Is an Early Biomarker of Thermal Stress in the Coral Acropora millepora

PubMed Central

Motti, Cherie A.; Miller, David J.; van Oppen, Madeleine J. H.

2015-01-01

Bleaching episodes caused by increasing seawater temperatures may induce mass coral mortality and are regarded as one of the biggest threats to coral reef ecosystems worldwide. The current consensus is that this phenomenon results from enhanced production of harmful reactive oxygen species (ROS) that disrupt the symbiosis between corals and their endosymbiotic dinoflagellates, Symbiodinium. Here, the responses of two important antioxidant defence components, the host coenzyme Q (CoQ) and symbiont plastoquinone (PQ) pools, are investigated for the first time in colonies of the scleractinian coral, Acropora millepora, during experimentally-induced bleaching under ecologically relevant conditions. Liquid chromatography-mass spectrometry (LC-MS) was used to quantify the states of these two pools, together with physiological parameters assessing the general state of the symbiosis (including photosystem II photochemical efficiency, chlorophyll concentration and Symbiodinium cell densities). The results show that the responses of the two antioxidant systems occur on different timescales: (i) the redox state of the Symbiodinium PQ pool remained stable until twelve days into the experiment, after which there was an abrupt oxidative shift; (ii) by contrast, an oxidative shift of approximately 10% had occurred in the host CoQ pool after 6 days of thermal stress, prior to significant changes in any other physiological parameter measured. Host CoQ pool oxidation is thus an early biomarker of thermal stress in corals, and this antioxidant pool is likely to play a key role in quenching thermally-induced ROS in the coral-algal symbiosis. This study adds to a growing body of work that indicates host cellular responses may precede the bleaching process and symbiont dysfunction. PMID:26426118

A Legionella Effector Disrupts Host Cytoskeletal Structure by Cleaving Actin

DOE PAGES

Liu, Yao; Zhu, Wenhan; Tan, Yunhao; ...

2017-01-27

Legionella pneumophila, the etiological agent of Legionnaires' disease, replicates intracellularly in protozoan and human hosts. Successful colonization and replication of this pathogen in host cells requires the Dot/Icm type IVB secretion system, which translocates approximately 300 effector proteins into the host cell to modulate various cellular processes. In this study, we identified RavK as a Dot/Icm substrate that targets the host cytoskeleton and reduces actin filament abundance in mammalian cells upon ectopic expression. RavK harbors an H 95E XXH 99 motif associated with diverse metalloproteases, which is essential for the inhibition of yeast growth and for the induction of cellmore » rounding in HEK293T cells. We demonstrate that the actin protein itself is the cellular target of RavK and that this effector cleaves actin at a site between residues Thr351 and Phe352. Importantly, RavK-mediated actin cleavage also occurs during L. pneumophila infection. Cleavage by RavK abolishes the ability of actin to form polymers. Furthermore, an F352A mutation renders actin resistant to RavK-mediated cleavage; expression of the mutant in mammalian cells suppresses the cell rounding phenotype caused by RavK, further establishing that actin is the physiological substrate of RavK. Furthermore, L. pneumophila exploits components of the host cytoskeleton by multiple effectors with distinct mechanisms, highlighting the importance of modulating cellular processes governed by the actin cytoskeleton in the intracellular life cycle of this pathogen.« less

Coral disease physiology: the impact of Acroporid white syndrome on Symbiodinium

NASA Astrophysics Data System (ADS)

Roff, G.; Kvennefors, E. C. E.; Ulstrup, K. E.; Fine, M.; Hoegh-Guldberg, O.

2008-06-01

Acroporid white syndrome, a disease-like syndrome from the Great Barrier Reef, results from degenerative host tissue at lesion borders. Tissue preceding lesion borders appears visually healthy, but it is currently unclear whether the endosymbiotic zooxanthellae ( Symbiodinium) are physiologically impacted. Compared to healthy colonies, this study found no significant differences in symbiont density, mitotic index or chlorophyll a content in tissue bordering (0 cm), and 8 cm away from white syndrome lesions. Using chlorophyll a fluorescence techniques, the border tissue did not appear to be photosynthetically compromised, and Symbiodinium extracted from this area were photosynthetically competent. Transmission electron microscopy revealed extensive degeneration of host tissues surrounding symbionts in affected areas, however, Symbiodinium cells were structurally intact with no sign of in situ degradation. Collectively, these results suggest that Symbiodinium at white syndrome lesion borders exist in a dynamic intra-cellular state during active host tissue loss, yet remain physiologically uncompromised.

[Bacterial Translocation from Intestine: Microbiological, Immunological and Pathophysiological Aspects].

PubMed

Podoprigora, G I; Kafarskaya, L I; Bainov, N A; Shkoporov, A N

2015-01-01

Bacterial translocation (BT) is both pathology and physiology phenomenon. In healthy newborns it accompanies the process of establishing the autochthonous intestinal microbiota and the host microbiome. In immunodeficiency it can be an aethio-pathogenetic link and a manifestation of infection or septic complications. The host colonization resistance to exogenous microbic colonizers is provided by gastrointestinal microbiota in concert with complex constitutional and adaptive defense mechanisms. BT may be result of barrier dysfunction and self-purification mechanisms involving the host myeloid cell phagocytic system and opsonins. Dynamic cell humoral response to microbial molecular patterns that occurs on the mucous membranes initiates receptorsignalingpathways and cascade ofreactions. Their vector and results are largely determined by cross-reactivity between microbiome and the host genome. Enterocyte barriers interacting with microbiota play leading role in providing adaptive, homeostatic and stress host reactivity. Microcirculatory ischemic tissue alterations and inflammatory reactions increase the intestinal barrier permeability and BT These processes a well as mechanisms for apoptotic cells and bacteria clearance are justified to be of prospective research interest. The inflammatory and related diseases caused by alteration and dysfunction of the intestinal barrier are reasonably considered as diseases of single origin. Maternal microbiota affects theformation of the innate immune system and the microbiota of the newborn, including intestinal commensal translocation during lactation. Deeper understanding of intestinal barrier mechanisms needs complex microbiological, immunological, pathophysiological, etc. investigations using adequate biomodels, including gnotobiotic animals.

Linking host prokaryotic physiology to viral lifestyle dynamics in a temperate freshwater lake (Lake Pavin, France).

PubMed

Palesse, S; Colombet, J; Pradeep Ram, A S; Sime-Ngando, T

2014-11-01

In aquatic ecosystems, fluctuations in environmental conditions and prokaryotic host physiological states can strongly affect the dynamics of viral life strategies. The influence of prokaryote physiology and environmental factors on viral replication cycles (lytic and lysogeny) was investigated from April to September 2011 at three different strata (epi, meta, and hypolimnion) in the mixolimnion of deep volcanic temperate freshwater Lake Pavin (France). Overall, the euphotic region (epi and metalimnion) was more dynamic and showed significant variation in microbial standing stocks, prokaryotic physiological state, and viral life strategies compared to the aphotic hypolimnion which was stable within sampled months. The prokaryotic host physiology as inferred from the nucleic acid content of prokaryotic cells (high or low nucleic acid) was strongly regulated by the chlorophyll concentration. The predominance of the high nucleic acid (HNA) prokaryotes (cells) over low nucleic acid (LNA) prokaryotes (cells) in the spring (HNA/LNA = 1.2) and vice versa in the summer period (HNA/LNA = 0.4) suggest that the natural prokaryotic communities underwent major shifts in their physiological states during investigated time period. The increase in the percentage of inducible lysogenic prokaryotes in the summer period was associated with the switch in the dominance of LNA over HNA cells, which coincided with the periods of strong resource (nutrient) limitation. This supports the idea that lysogeny represents a maintenance strategy for viruses in unproductive or harsh nutrient/host conditions. A negative correlation of percentage of lysogenic prokaryotes with HNA cell abundance and chlorophyll suggest that lysogenic cycle is closely related to prokaryotic cells which are stressed or starved due to unavailability of resources for its growth and activity. Our results provide support to previous findings that changes in prokaryote physiology are critical for the promotion and establishment of lysogeny in aquatic ecosystems, which are prone to constant environmental fluctuations.

Indirect effects of parasitism: costs of infection to other individuals can be greater than direct costs borne by the host.

PubMed

Granroth-Wilding, Hanna M V; Burthe, Sarah J; Lewis, Sue; Herborn, Katherine A; Takahashi, Emi A; Daunt, Francis; Cunningham, Emma J A

2015-07-22

Parasitic infection has a direct physiological cost to hosts but may also alter how hosts interact with other individuals in their environment. Such indirect effects may alter both host fitness and the fitness of other individuals in the host's social network, yet the relative impact of direct and indirect effects of infection are rarely quantified. During reproduction, a host's social environment includes family members who may be in conflict over resource allocation. In such situations, infection may alter how resources are allocated, thereby redistributing the costs of parasitism between individuals. Here, we experimentally reduce parasite burdens of parent and/or nestling European shags (Phalacrocorax aristotelis) infected with Contracaecum nematodes in a factorial design, then simultaneously measure the impact of an individual's infection on all family members. We found no direct effect of infection on parent or offspring traits but indirect effects were detected in all group members, with both immediate effects (mass change and survival) and longer-term effects (timing of parents' subsequent breeding). Our results show that parasite infection can have a major impact on individuals other than the host, suggesting that the effect of parasites on population processes may be greater than previously thought. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

MicroRNAs in large herpesvirus DNA genomes: recent advances.

PubMed

Sorel, Océane; Dewals, Benjamin G

2016-08-01

MicroRNAs (miRNAs) are small non-coding RNAs (ncRNAs) that regulate gene expression. They alter mRNA translation through base-pair complementarity, leading to regulation of genes during both physiological and pathological processes. Viruses have evolved mechanisms to take advantage of the host cells to multiply and/or persist over the lifetime of the host. Herpesviridae are a large family of double-stranded DNA viruses that are associated with a number of important diseases, including lymphoproliferative diseases. Herpesviruses establish lifelong latent infections through modulation of the interface between the virus and its host. A number of reports have identified miRNAs in a very large number of human and animal herpesviruses suggesting that these short non-coding transcripts could play essential roles in herpesvirus biology. This review will specifically focus on the recent advances on the functions of herpesvirus miRNAs in infection and pathogenesis.

Immune responses to implants - a review of the implications for the design of immunomodulatory biomaterials.

PubMed

Franz, Sandra; Rammelt, Stefan; Scharnweber, Dieter; Simon, Jan C

2011-10-01

A key for long-term survival and function of biomaterials is that they do not elicit a detrimental immune response. As biomaterials can have profound impacts on the host immune response the concept emerged to design biomaterials that are able to trigger desired immunological outcomes and thus support the healing process. However, engineering such biomaterials requires an in-depth understanding of the host inflammatory and wound healing response to implanted materials. One focus of this review is to outline the up-to-date knowledge on immune responses to biomaterials. Understanding the complex interactions of host response and material implants reveals the need for and also the potential of "immunomodulating" biomaterials. Based on this knowledge, we discuss strategies of triggering appropriate immune responses by functional biomaterials and highlight recent approaches of biomaterials that mimic the physiological extracellular matrix and modify cellular immune responses. Copyright © 2011 Elsevier Ltd. All rights reserved.

The sickle-cell trait modifies the intensity and specificity of the immune response against P. falciparum malaria and leads to acquired protective immunity.

PubMed

Bayoumi, R A

1987-03-01

It is proposed that the in vivo mechanism of protection against falciparum malaria in individuals of the Hb AS genotype is not due solely to the adverse influence of Hb AS erythrocytes on the intraerythrocytic growth and development of P. falciparum. Instead, the simple physiological effect of Hb S on parasite growth appears to trigger an in vivo process of enhancement of the intensity and/or specificity of the host immune response, leading to acquired protective immunity, in a process simulating vaccination. Testing the hypothesis may lead to the identification of plasmodial antigens that induce protective responses in the human host and distinguish them from non-protective, immunosuppressive or decoy antigens that promote parasite survival. This may ultimately help in the selection of candidate antigens for a malaria blood-stage vaccine.

Metabolic and physiological interdependencies in the Bathymodiolus azoricus symbiosis

PubMed Central

Ponnudurai, Ruby; Kleiner, Manuel; Sayavedra, Lizbeth; Petersen, Jillian M; Moche, Martin; Otto, Andreas; Becher, Dörte; Takeuchi, Takeshi; Satoh, Noriyuki; Dubilier, Nicole; Schweder, Thomas; Markert, Stephanie

2017-01-01

The hydrothermal vent mussel Bathymodiolus azoricus lives in an intimate symbiosis with two types of chemosynthetic Gammaproteobacteria in its gills: a sulfur oxidizer and a methane oxidizer. Despite numerous investigations over the last decades, the degree of interdependence between the three symbiotic partners, their individual metabolic contributions, as well as the mechanism of carbon transfer from the symbionts to the host are poorly understood. We used a combination of proteomics and genomics to investigate the physiology and metabolism of the individual symbiotic partners. Our study revealed that key metabolic functions are most likely accomplished jointly by B. azoricus and its symbionts: (1) CO2 is pre-concentrated by the host for carbon fixation by the sulfur-oxidizing symbiont, and (2) the host replenishes essential biosynthetic TCA cycle intermediates for the sulfur-oxidizing symbiont. In return (3), the sulfur oxidizer may compensate for the host's putative deficiency in amino acid and cofactor biosynthesis. We also identified numerous ‘symbiosis-specific' host proteins by comparing symbiont-containing and symbiont-free host tissues and symbiont fractions. These proteins included a large complement of host digestive enzymes in the gill that are likely involved in symbiont digestion and carbon transfer from the symbionts to the host. PMID:27801908

Metabolic and physiological interdependencies in the Bathymodiolus azoricus symbiosis.

PubMed

Ponnudurai, Ruby; Kleiner, Manuel; Sayavedra, Lizbeth; Petersen, Jillian M; Moche, Martin; Otto, Andreas; Becher, Dörte; Takeuchi, Takeshi; Satoh, Noriyuki; Dubilier, Nicole; Schweder, Thomas; Markert, Stephanie

2017-02-01

The hydrothermal vent mussel Bathymodiolus azoricus lives in an intimate symbiosis with two types of chemosynthetic Gammaproteobacteria in its gills: a sulfur oxidizer and a methane oxidizer. Despite numerous investigations over the last decades, the degree of interdependence between the three symbiotic partners, their individual metabolic contributions, as well as the mechanism of carbon transfer from the symbionts to the host are poorly understood. We used a combination of proteomics and genomics to investigate the physiology and metabolism of the individual symbiotic partners. Our study revealed that key metabolic functions are most likely accomplished jointly by B. azoricus and its symbionts: (1) CO 2 is pre-concentrated by the host for carbon fixation by the sulfur-oxidizing symbiont, and (2) the host replenishes essential biosynthetic TCA cycle intermediates for the sulfur-oxidizing symbiont. In return (3), the sulfur oxidizer may compensate for the host's putative deficiency in amino acid and cofactor biosynthesis. We also identified numerous 'symbiosis-specific' host proteins by comparing symbiont-containing and symbiont-free host tissues and symbiont fractions. These proteins included a large complement of host digestive enzymes in the gill that are likely involved in symbiont digestion and carbon transfer from the symbionts to the host.

Host-regulated Hepatitis B Virus Capsid Assembly in a Mammalian Cell-free System.

PubMed

Liu, Kuancheng; Hu, Jianming

2018-04-20

The hepatitis B virus (HBV) is an important global human pathogen and represents a major cause of hepatitis, liver cirrhosis and liver cancer. The HBV capsid is composed of multiple copies of a single viral protein, the capsid or core protein (HBc), plays multiple roles in the viral life cycle, and has emerged recently as a major target for developing antiviral therapies against HBV infection. Although several systems have been developed to study HBV capsid assembly, including heterologous overexpression systems like bacteria and insect cells, in vitro assembly using purified protein, and mammalian cell culture systems, the requirement for non-physiological concentrations of HBc and salts and the difficulty in manipulating host regulators of assembly presents major limitations for detailed studies on capsid assembly under physiologically relevant conditions. We have recently developed a mammalian cell-free system based on the rabbit reticulocyte lysate (RRL), in which HBc is expressed at physiological concentrations and assembles into capsids under near-physiological conditions. This system has already revealed HBc assembly requirements that are not anticipated based on previous assembly systems. Furthermore, capsid assembly in this system is regulated by endogenous host factors that can be readily manipulated. Here we present a detailed protocol for this cell-free capsid assembly system, including an illustration on how to manipulate host factors that regulate assembly.

Gut immune system: a new frontier for nutritional modulation of gut health

USDA-ARS?s Scientific Manuscript database

The gut represents a continuously evolving ecosystem consisting of trillions of commensal bacteria living in symbiosis with the host. The host-microbe interplay plays a crucial role in physiological development and health of the host. There is increasing evidence that shows a dynamic interaction be...

Abiotic stress and the plant circadian clock

PubMed Central

Sanchez, Alfredo; Shin, Jieun

2011-01-01

In this review, we focus on the interaction between the circadian clock of higher plants to that of metabolic and physiological processes that coordinate growth and performance under a predictable, albeit changing environment. In this, the phytochrome and cryptochrome photoreceptors have shown to be important, but not essential for oscillator control under diurnal cycles of light and dark. From this foundation, we will examine how emerging findings have firmly linked the circadian clock, as a central mediator in the coordination of metabolism, to maintain homeostasis. This occurs by oscillator synchronization of global transcription, which leads to a dynamic control of a host of physiological processes. These include the determination of the levels of primary and secondary metabolites, and the anticipation of future environmental stresses, such as mid-day drought and midnight coldness. Interestingly, metabolic and stress cues themselves appear to feedback on oscillator function. In such a way, the circadian clock of plants and abiotic-stress tolerance appear to be firmly interconnected processes. PMID:21325898

Mechanistic links between gut microbial community dynamics, microbial functions and metabolic health.

PubMed

Ha, Connie W Y; Lam, Yan Y; Holmes, Andrew J

2014-11-28

Gut microbes comprise a high density, biologically active community that lies at the interface of an animal with its nutritional environment. Consequently their activity profoundly influences many aspects of the physiology and metabolism of the host animal. A range of microbial structural components and metabolites directly interact with host intestinal cells and tissues to influence nutrient uptake and epithelial health. Endocrine, neuronal and lymphoid cells in the gut also integrate signals from these microbial factors to influence systemic responses. Dysregulation of these host-microbe interactions is now recognised as a major risk factor in the development of metabolic dysfunction. This is a two-way process and understanding the factors that tip host-microbiome homeostasis over to dysbiosis requires greater appreciation of the host feedbacks that contribute to regulation of microbial community composition. To date, numerous studies have employed taxonomic profiling approaches to explore the links between microbial composition and host outcomes (especially obesity and its comorbidities), but inconsistent host-microbe associations have been reported. Available data indicates multiple factors have contributed to discrepancies between studies. These include the high level of functional redundancy in host-microbiome interactions combined with individual variation in microbiome composition; differences in study design, diet composition and host system between studies; and inherent limitations to the resolution of rRNA-based community profiling. Accounting for these factors allows for recognition of the common microbial and host factors driving community composition and development of dysbiosis on high fat diets. New therapeutic intervention options are now emerging.

Mechanistic links between gut microbial community dynamics, microbial functions and metabolic health

PubMed Central

Ha, Connie WY; Lam, Yan Y; Holmes, Andrew J

2014-01-01

Gut microbes comprise a high density, biologically active community that lies at the interface of an animal with its nutritional environment. Consequently their activity profoundly influences many aspects of the physiology and metabolism of the host animal. A range of microbial structural components and metabolites directly interact with host intestinal cells and tissues to influence nutrient uptake and epithelial health. Endocrine, neuronal and lymphoid cells in the gut also integrate signals from these microbial factors to influence systemic responses. Dysregulation of these host-microbe interactions is now recognised as a major risk factor in the development of metabolic dysfunction. This is a two-way process and understanding the factors that tip host-microbiome homeostasis over to dysbiosis requires greater appreciation of the host feedbacks that contribute to regulation of microbial community composition. To date, numerous studies have employed taxonomic profiling approaches to explore the links between microbial composition and host outcomes (especially obesity and its comorbidities), but inconsistent host-microbe associations have been reported. Available data indicates multiple factors have contributed to discrepancies between studies. These include the high level of functional redundancy in host-microbiome interactions combined with individual variation in microbiome composition; differences in study design, diet composition and host system between studies; and inherent limitations to the resolution of rRNA-based community profiling. Accounting for these factors allows for recognition of the common microbial and host factors driving community composition and development of dysbiosis on high fat diets. New therapeutic intervention options are now emerging. PMID:25469018

The impact of pollen consumption on honey bee (Apis mellifera) digestive physiology and carbohydrate metabolism.

PubMed

Ricigliano, Vincent A; Fitz, William; Copeland, Duan C; Mott, Brendon M; Maes, Patrick; Floyd, Amy S; Dockstader, Arnold; Anderson, Kirk E

2017-10-01

Carbohydrate-active enzymes play an important role in the honey bee (Apis mellifera) due to its dietary specialization on plant-based nutrition. Secretory glycoside hydrolases (GHs) produced in worker head glands aid in the processing of floral nectar into honey and are expressed in accordance with age-based division of labor. Pollen utilization by the honey bee has been investigated in considerable detail, but little is known about the metabolic fate of indigestible carbohydrates and glycosides in pollen biomass. Here, we demonstrate that pollen consumption stimulates the hydrolysis of sugars that are toxic to the bee (xylose, arabinose, mannose). GHs produced in the head accumulate in the midgut and persist in the hindgut that harbors a core microbial community composed of approximately 10 8 bacterial cells. Pollen consumption significantly impacted total and specific bacterial abundance in the digestive tract. Bacterial isolates representing major fermentative gut phylotypes exhibited primarily membrane-bound GH activities that may function in tandem with soluble host enzymes retained in the hindgut. Additionally, we found that plant-originating β-galactosidase activity in pollen may be sufficient, in some cases, for probable physiological activity in the gut. These findings emphasize the potential relative contributions of host, bacteria, and pollen enzyme activities to carbohydrate breakdown, which may be tied to gut microbiome dynamics and associated host nutrition. © 2017 Wiley Periodicals, Inc.

Antibiotic-Induced Changes in the Intestinal Microbiota and Disease.

PubMed

Becattini, Simone; Taur, Ying; Pamer, Eric G

2016-06-01

The gut microbiota is a key player in many physiological and pathological processes occurring in humans. Recent investigations suggest that the efficacy of some clinical approaches depends on the action of commensal bacteria. Antibiotics are invaluable weapons to fight infectious diseases. However, by altering the composition and functions of the microbiota, they can also produce long-lasting deleterious effects for the host. The emergence of multidrug-resistant pathogens raises concerns about the common, and at times inappropriate, use of antimicrobial agents. Here we review the most recently discovered connections between host pathophysiology, microbiota, and antibiotics highlighting technological platforms, mechanistic insights, and clinical strategies to enhance resistance to diseases by preserving the beneficial functions of the microbiota. Copyright © 2016 Elsevier Ltd. All rights reserved.

Avian host defense peptides.

PubMed

Cuperus, Tryntsje; Coorens, Maarten; van Dijk, Albert; Haagsman, Henk P

2013-11-01

Host defense peptides (HDPs) are important effector molecules of the innate immune system of vertebrates. These antimicrobial peptides are also present in invertebrates, plants and fungi. HDPs display broad-spectrum antimicrobial activities and fulfill an important role in the first line of defense of many organisms. It is becoming increasingly clear that in the animal kingdom the functions of HDPs are not confined to direct antimicrobial actions. Research in mammals has indicated that HDPs have many immunomodulatory functions and are also involved in other physiological processes ranging from development to wound healing. During the past five years our knowledge about avian HDPs has increased considerably. This review addresses our current knowledge on the evolution, regulation and biological functions of HDPs of birds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Inflammatory phenotypes in the intestine of poultry: Not all inflammation is created equally

USDA-ARS?s Scientific Manuscript database

The intestinal tract harbors a diverse community of microbes that have co-evolved with the host immune system. Although many of these microbes execute functions that are critical for host physiology, the host immune system must control the microbial community so that the dynamics of this interdepen...

Various antibiotic alternative strategies to reduce pathogen-induced inflammation and to maintain gut homeostasis in broiler chickens

USDA-ARS?s Scientific Manuscript database

The gut represents a continuously evolving ecosystem consisting of trillions of commensal bacteria living in symbiosis with the host. This host-microbe interplay plays a crucial role in physiological development and health of the host. There is increasing evidence that shows a dynamic interaction b...

Mycobacterium tuberculosis Transcription Machinery: Ready To Respond to Host Attacks

PubMed Central

Flentie, Kelly; Garner, Ashley L.

2016-01-01

Regulating responses to stress is critical for all bacteria, whether they are environmental, commensal, or pathogenic species. For pathogenic bacteria, successful colonization and survival in the host are dependent on adaptation to diverse conditions imposed by the host tissue architecture and the immune response. Once the bacterium senses a hostile environment, it must enact a change in physiology that contributes to the organism's survival strategy. Inappropriate responses have consequences; hence, the execution of the appropriate response is essential for survival of the bacterium in its niche. Stress responses are most often regulated at the level of gene expression and, more specifically, transcription. This minireview focuses on mechanisms of regulating transcription initiation that are required by Mycobacterium tuberculosis to respond to the arsenal of defenses imposed by the host during infection. In particular, we highlight how certain features of M. tuberculosis physiology allow this pathogen to respond swiftly and effectively to host defenses. By enacting highly integrated and coordinated gene expression changes in response to stress, M. tuberculosis is prepared for battle against the host defense and able to persist within the human population. PMID:26883824

How does healthy aging impact on the circadian clock?

PubMed

Popa-Wagner, Aurel; Buga, Ana-Maria; Dumitrascu, Dinu Iuliu; Uzoni, Adriana; Thome, Johannes; Coogan, Andrew N

2017-02-01

Circadian rhythms are recurring patterns in a host of physiological and other parameters that recur with periods of near 24 h. These rhythms reflect the temporal organization of an organism's homeostatic control systems and as such are key processes in ensuring optimal physiological performance. Dysfunction of circadian processes is linked with adverse health conditions. In this review we highlight the evidence that normal, healthy aging is associated with changes in the circadian system; we examine the molecular mechanisms through which such changes may arise, discuss whether more robust circadian function is a predictor of longevity and highlight the role of circadian rhythms in age-related diseases. Overall, the literature shows that aging is associated with marked changes in circadian processes, both at the behavioral and molecular levels, and the molecular mechanisms through which such changes arise remain to be elucidated, but may involve inflammatory process, redox homeostasis and epigenetic modifications. Understanding the nature of age-related circadian dysfunction will allow for the design of chronotherapeutic intervention strategies to attenuate circadian dysfunction and thus improve health and quality of life.

Molecular basis of Trypanosoma cruzi and Leishmania interaction with their host(s): exploitation of immune and defense mechanisms by the parasite leading to persistence and chronicity, features reminiscent of immune system evasion strategies in cancer diseases.

PubMed

Ouaissi, Ali; Ouaissi, Mehdi

2005-01-01

A number of features occurring during host-parasite interactions in Chagas disease caused by the protozoan parasite, Trypanosoma cruzi, and Leishmaniasis, caused by a group of kinetoplastid protozoan parasites are reminiscent of those observed in cancer diseases. In fact,although the cancer is not a single disease, and that T.cruzi and Leishmania are sophisticated eukaryotic parasites presenting a high level of genotypic variability the growth of the parasites in their host and that of cancer cells share at least one common feature, that is their mutual capacity for rapid cell division. Surprisingly, the parasitic diseases and cancers share some immune evasion strategies. Consideration of these immunological alterations must be added to the evaluation of the pathogenic processes. The molecular and functional characterization of virulence factors and the study of their effect on the arms of the immune system have greatly improved understanding of the regulation of immune effectors functions. The purpose of this review is to analyze some of the current data related to the regulatory components or processes originating from the parasite that control or interfere with host cell physiology. Attempts are also made to delineate some similarities between the immune evasion strategies that parasites and tumors employ. The elucidation of the mode of action of parasite virulence factors toward the host cell allow not only provide us with a more comprehensive view of the host-parasite relationships but may also represent a step forward in efforts aimed to identify new target molecules for therapeutic intervention.

A comprehensive collection of systems biology data characterizing the host response to viral infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aevermann, Brian D.; Pickett, Brett E.; Kumar, Sanjeev

The Systems Biology for Infectious Diseases Research program was established by the U.S. National Institute of Allergy and Infectious Diseases to investigate host-pathogen interactions at a systems level. This program generated 47 transcriptomic and proteomic datasets from 30 studies that investigate in vivo and in vitro host responses to viral infections. Human pathogens in the Orthomyxoviridae and Coronaviridae families, especially pandemic H1N1 and avian H5N1 influenza A viruses and severe acute respiratory syndrome coronavirus (SARS-CoV), were investigated. Study validation was demonstrated via experimental quality control measures and meta-analysis of independent experiments performed under similar conditions. Primary assay results are archivedmore » at the GEO and PeptideAtlas public repositories, while processed statistical results together with standardized metadata are publically available at the Influenza Research Database (www.fludb.org) and the Virus Pathogen Resource (www.viprbrc.org). As a result, by comparing data from mutant versus wild-type virus and host strains, RNA versus protein differential expression, and infection with genetically similar strains, these data can be used to further investigate genetic and physiological determinants of host responses to viral infection.« less

A comprehensive collection of systems biology data characterizing the host response to viral infection

DOE PAGES

Aevermann, Brian D.; Pickett, Brett E.; Kumar, Sanjeev; ...

2014-10-14

The Systems Biology for Infectious Diseases Research program was established by the U.S. National Institute of Allergy and Infectious Diseases to investigate host-pathogen interactions at a systems level. This program generated 47 transcriptomic and proteomic datasets from 30 studies that investigate in vivo and in vitro host responses to viral infections. Human pathogens in the Orthomyxoviridae and Coronaviridae families, especially pandemic H1N1 and avian H5N1 influenza A viruses and severe acute respiratory syndrome coronavirus (SARS-CoV), were investigated. Study validation was demonstrated via experimental quality control measures and meta-analysis of independent experiments performed under similar conditions. Primary assay results are archivedmore » at the GEO and PeptideAtlas public repositories, while processed statistical results together with standardized metadata are publically available at the Influenza Research Database (www.fludb.org) and the Virus Pathogen Resource (www.viprbrc.org). As a result, by comparing data from mutant versus wild-type virus and host strains, RNA versus protein differential expression, and infection with genetically similar strains, these data can be used to further investigate genetic and physiological determinants of host responses to viral infection.« less

A comprehensive collection of systems biology data characterizing the host response to viral infection.

PubMed

Aevermann, Brian D; Pickett, Brett E; Kumar, Sanjeev; Klem, Edward B; Agnihothram, Sudhakar; Askovich, Peter S; Bankhead, Armand; Bolles, Meagen; Carter, Victoria; Chang, Jean; Clauss, Therese R W; Dash, Pradyot; Diercks, Alan H; Eisfeld, Amie J; Ellis, Amy; Fan, Shufang; Ferris, Martin T; Gralinski, Lisa E; Green, Richard R; Gritsenko, Marina A; Hatta, Masato; Heegel, Robert A; Jacobs, Jon M; Jeng, Sophia; Josset, Laurence; Kaiser, Shari M; Kelly, Sara; Law, G Lynn; Li, Chengjun; Li, Jiangning; Long, Casey; Luna, Maria L; Matzke, Melissa; McDermott, Jason; Menachery, Vineet; Metz, Thomas O; Mitchell, Hugh; Monroe, Matthew E; Navarro, Garnet; Neumann, Gabriele; Podyminogin, Rebecca L; Purvine, Samuel O; Rosenberger, Carrie M; Sanders, Catherine J; Schepmoes, Athena A; Shukla, Anil K; Sims, Amy; Sova, Pavel; Tam, Vincent C; Tchitchek, Nicolas; Thomas, Paul G; Tilton, Susan C; Totura, Allison; Wang, Jing; Webb-Robertson, Bobbie-Jo; Wen, Ji; Weiss, Jeffrey M; Yang, Feng; Yount, Boyd; Zhang, Qibin; McWeeney, Shannon; Smith, Richard D; Waters, Katrina M; Kawaoka, Yoshihiro; Baric, Ralph; Aderem, Alan; Katze, Michael G; Scheuermann, Richard H

2014-01-01

The Systems Biology for Infectious Diseases Research program was established by the U.S. National Institute of Allergy and Infectious Diseases to investigate host-pathogen interactions at a systems level. This program generated 47 transcriptomic and proteomic datasets from 30 studies that investigate in vivo and in vitro host responses to viral infections. Human pathogens in the Orthomyxoviridae and Coronaviridae families, especially pandemic H1N1 and avian H5N1 influenza A viruses and severe acute respiratory syndrome coronavirus (SARS-CoV), were investigated. Study validation was demonstrated via experimental quality control measures and meta-analysis of independent experiments performed under similar conditions. Primary assay results are archived at the GEO and PeptideAtlas public repositories, while processed statistical results together with standardized metadata are publically available at the Influenza Research Database (www.fludb.org) and the Virus Pathogen Resource (www.viprbrc.org). By comparing data from mutant versus wild-type virus and host strains, RNA versus protein differential expression, and infection with genetically similar strains, these data can be used to further investigate genetic and physiological determinants of host responses to viral infection.

A comprehensive collection of systems biology data characterizing the host response to viral infection

PubMed Central

Aevermann, Brian D.; Pickett, Brett E.; Kumar, Sanjeev; Klem, Edward B.; Agnihothram, Sudhakar; Askovich, Peter S.; Bankhead, Armand; Bolles, Meagen; Carter, Victoria; Chang, Jean; Clauss, Therese R.W.; Dash, Pradyot; Diercks, Alan H.; Eisfeld, Amie J.; Ellis, Amy; Fan, Shufang; Ferris, Martin T.; Gralinski, Lisa E.; Green, Richard R.; Gritsenko, Marina A.; Hatta, Masato; Heegel, Robert A.; Jacobs, Jon M.; Jeng, Sophia; Josset, Laurence; Kaiser, Shari M.; Kelly, Sara; Law, G. Lynn; Li, Chengjun; Li, Jiangning; Long, Casey; Luna, Maria L.; Matzke, Melissa; McDermott, Jason; Menachery, Vineet; Metz, Thomas O.; Mitchell, Hugh; Monroe, Matthew E.; Navarro, Garnet; Neumann, Gabriele; Podyminogin, Rebecca L.; Purvine, Samuel O.; Rosenberger, Carrie M.; Sanders, Catherine J.; Schepmoes, Athena A.; Shukla, Anil K.; Sims, Amy; Sova, Pavel; Tam, Vincent C.; Tchitchek, Nicolas; Thomas, Paul G.; Tilton, Susan C.; Totura, Allison; Wang, Jing; Webb-Robertson, Bobbie-Jo; Wen, Ji; Weiss, Jeffrey M.; Yang, Feng; Yount, Boyd; Zhang, Qibin; McWeeney, Shannon; Smith, Richard D.; Waters, Katrina M.; Kawaoka, Yoshihiro; Baric, Ralph; Aderem, Alan; Katze, Michael G.; Scheuermann, Richard H.

2014-01-01

The Systems Biology for Infectious Diseases Research program was established by the U.S. National Institute of Allergy and Infectious Diseases to investigate host-pathogen interactions at a systems level. This program generated 47 transcriptomic and proteomic datasets from 30 studies that investigate in vivo and in vitro host responses to viral infections. Human pathogens in the Orthomyxoviridae and Coronaviridae families, especially pandemic H1N1 and avian H5N1 influenza A viruses and severe acute respiratory syndrome coronavirus (SARS-CoV), were investigated. Study validation was demonstrated via experimental quality control measures and meta-analysis of independent experiments performed under similar conditions. Primary assay results are archived at the GEO and PeptideAtlas public repositories, while processed statistical results together with standardized metadata are publically available at the Influenza Research Database (www.fludb.org) and the Virus Pathogen Resource (www.viprbrc.org). By comparing data from mutant versus wild-type virus and host strains, RNA versus protein differential expression, and infection with genetically similar strains, these data can be used to further investigate genetic and physiological determinants of host responses to viral infection. PMID:25977790

Construction and screening of marine metagenomic libraries.

PubMed

Weiland, Nancy; Löscher, Carolin; Metzger, Rebekka; Schmitz, Ruth

2010-01-01

Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. They harbor an enormous diversity of microbes with still unknown and probably new physiological characteristics. Besides, the surfaces of marine multicellular organisms are typically covered by a consortium of epibiotic bacteria and act as barriers, where diverse interactions between microorganisms and hosts take place. Thus, microbial diversity in the water column of the oceans and the microbial consortia on marine tissues of multicellular organisms are rich sources for isolating novel bioactive compounds and genes. Here we describe the sampling, construction of large-insert metagenomic libraries from marine habitats and exemplarily one function based screen of metagenomic clones.

Host-Microbe Interactions in Microgravity: Assessment and Implications

PubMed Central

Foster, Jamie S.; Wheeler, Raymond M.; Pamphile, Regine

2014-01-01

Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes. PMID:25370197

Host-microbe interactions in microgravity: assessment and implications.

PubMed

Foster, Jamie S; Wheeler, Raymond M; Pamphile, Regine

2014-05-26

Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes.

Exposure to the leaf litter microbiome of healthy adults protects seedlings from pathogen damage.

PubMed

Christian, Natalie; Herre, Edward Allen; Mejia, Luis C; Clay, Keith

2017-07-12

It is increasingly recognized that microbiota affect host health and physiology. However, it is unclear what factors shape microbiome community assembly in nature, and how microbiome assembly can be manipulated to improve host health. All plant leaves host foliar endophytic fungi, which make up a diverse, environmentally acquired fungal microbiota. Here, we experimentally manipulated assembly of the cacao tree ( Theobroma cacao ) fungal microbiome in nature and tested the effect of assembly outcome on host health. Using next-generation sequencing, as well as culture-based methods coupled with Sanger sequencing, we found that manipulating leaf litter exposure and location within the forest canopy significantly altered microbiome composition in cacao. Exposing cacao seedlings to leaf litter from healthy conspecific adults enriched the seedling microbiome with Colletotrichum tropicale , a fungal endophyte known to enhance pathogen resistance of cacao seedlings by upregulating host defensive pathways. As a result, seedlings exposed to healthy conspecific litter experienced reduced pathogen damage. Our results link processes that affect the assembly and composition of microbiome communities to their functional consequences for host success, and have broad implications for understanding plant-microbe interactions. Deliberate manipulation of the plant-fungal microbiome also has potentially important applications for cacao production and other agricultural systems in general. © 2017 The Author(s).

Effects of diet and host access on fecundity and lifespan in two fruit fly species with different life history patterns

PubMed Central

Harwood, James F.; Chen, Kehui; Müller, Hans-Georg; Wang, Jane-Ling; Vargas, Roger I.; Carey, James R.

2013-01-01

The reproductive ability of female tephritids can be limited and prevented by denying access to host plants and restricting the dietary precursors of vitellogenesis. The mechanisms underlying the delayed egg production in each case are initiated by different physiological processes that are anticipated to have dissimilar effects on lifespan and reproductive ability later in life. The egg laying abilities of laboratory reared females of the Mediterranean fruit fly (Ceratitis capitata Wiedmann) and melon fly (Bactrocera cucurbitae Coquillett) from Hawaii are delayed or suppressed by limiting access to host fruits and dietary protein. In each case, this is expected to prevent the loss of lifespan associated with reproduction until protein or hosts are introduced. Two trends are observed in each species: Firstly, access to protein at eclosion leads to a greater probability of survival and higher reproductive ability than if it is delayed, and secondly, that delayed host access reduces lifetime reproductive ability without improving life expectancy. When host access and protein availability are delayed, the rate of reproductive senescence is reduced in the medfly, whereas the rate of reproductive senescence is generally increased in the melon fly. Overall, delaying reproduction lowers the fitness of females by constraining their fecundity for the remainder of the lifespan without extending the lifespan. PMID:23483775

Porites white patch syndrome: associated viruses and disease physiology

NASA Astrophysics Data System (ADS)

Lawrence, S. A.; Davy, J. E.; Wilson, W. H.; Hoegh-Guldberg, O.; Davy, S. K.

2015-03-01

In recent decades, coral reefs worldwide have undergone significant changes in response to various environmental and anthropogenic impacts. Among the numerous causes of reef degradation, coral disease is one factor that is to a large extent still poorly understood. Here, we characterize the physiology of white patch syndrome (WPS), a disease affecting poritid corals on the Great Barrier Reef. WPS manifests as small, generally discrete patches of tissue discolouration. Physiological analysis revealed that chlorophyll a content was significantly lower in lesions than in healthy tissues, while host protein content remained constant, suggesting that host tissue is not affected by WPS. This was confirmed by transmission electron microscope (TEM) examination, which showed intact host tissue within lesions. TEM also revealed that Symbiodinium cells are lost from the host gastrodermis with no apparent harm caused to the surrounding host tissue. Also present in the electron micrographs were numerous virus-like particles (VLPs), in both coral and Symbiodinium cells. Small (<50 nm diameter) icosahedral VLPs were significantly more abundant in coral tissue taken from diseased colonies, and there was an apparent, but not statistically significant, increase in abundance of filamentous VLPs in Symbiodinium cells from diseased colonies. There was no apparent increase in prokaryotic or eukaryotic microbial abundance in diseased colonies. Taken together, these results suggest that viruses infecting the coral and/or its resident Symbiodinium cells may be the causative agents of WPS.

Energetics of the host-dependent Mycobacterium Lepraemurium during transition to a capacity for extracellular growth

NASA Technical Reports Server (NTRS)

Dhople, A. M.; Hanks, J. H.

1975-01-01

The ATP measurements were refined to a point where the growth potential of microscopic samples of host-dependent microbes can be measured, even before an increase in microbial numbers has occurred. This tool differs from other biochemical indicators of physiologic states in its sensitivity and in the fact that it can be exploited with unwashed host-dependent and host-grown organisms.

Parasite-altered feeding behavior in insects: integrating functional and mechanistic research frontiers.

PubMed

Bernardo, Melissa A; Singer, Michael S

2017-08-15

Research on parasite-altered feeding behavior in insects is contributing to an emerging literature that considers possible adaptive consequences of altered feeding behavior for the host or the parasite. Several recent ecoimmunological studies show that insects can adaptively alter their foraging behavior in response to parasitism. Another body of recent work shows that infection by parasites can change the behavior of insect hosts to benefit the parasite; manipulations of host feeding behavior may be part of this phenomenon. Here, we address both the functional and the underlying physiological frontiers of parasite-altered feeding behavior in order to spur research that better integrates the two. Functional categories of parasite-altered behavior that are adaptive for the host include prophylaxis, therapy and compensation, while host manipulation is adaptive for the parasite. To better understand and distinguish prophylaxis, therapy and compensation, further study of physiological feedbacks affecting host sensory systems is especially needed. For host manipulation in particular, research on mechanisms by which parasites control host feedbacks will be important to integrate with functional approaches. We see this integration as critical to advancing the field of parasite-altered feeding behavior, which may be common in insects and consequential for human and environmental health. © 2017. Published by The Company of Biologists Ltd.

Behavioral Immunity in Insects

PubMed Central

de Roode, Jacobus C.; Lefèvre, Thierry

2012-01-01

Parasites can dramatically reduce the fitness of their hosts, and natural selection should favor defense mechanisms that can protect hosts against disease. Much work has focused on understanding genetic and physiological immunity against parasites, but hosts can also use behaviors to avoid infection, reduce parasite growth or alleviate disease symptoms. It is increasingly recognized that such behaviors are common in insects, providing strong protection against parasites and parasitoids. We review the current evidence for behavioral immunity in insects, present a framework for investigating such behavior, and emphasize that behavioral immunity may act through indirect rather than direct fitness benefits. We also discuss the implications for host-parasite co-evolution, local adaptation, and the evolution of non-behavioral physiological immune systems. Finally, we argue that the study of behavioral immunity in insects has much to offer for investigations in vertebrates, in which this topic has traditionally been studied. PMID:26466629

Implications of bioactive solute transfer from hosts to parasitic plants.

PubMed

Smith, Jason D; Mescher, Mark C; De Moraes, Consuelo M

2013-08-01

Parasitic plants--which make their living by extracting nutrients and other resources from other plants--are important components of many natural ecosystems; and some parasitic species are also devastating agricultural pests. To date, most research on plant parasitism has focused on nutrient transfer from host to parasite and the impacts of parasites on host plants. Far less work has addressed potential effects of the translocation of bioactive non-nutrient solutes-such as phytohormones, secondary metabolites, RNAs, and proteins-on the development and physiology of parasitic plants and on their subsequent interactions with other organisms such as insect herbivores. A growing number of recent studies document the transfer of such molecules from hosts to parasites and suggest that they may have significant impacts on parasite physiology and ecology. We review this literature and discuss potential implications for management and priorities for future research. Copyright © 2013 Elsevier Ltd. All rights reserved.

Campylobacter jejuni host tissue tropism: a consequence of its low-carb lifestyle?

PubMed

Thompson, Stuart A; Gaynor, Erin C

2008-11-13

Mechanisms underlying virulence properties of Campylobacter jejuni have historically been difficult to identify. In this issue of Cell Host & Microbe, Hofreuter et al. (2008) show that C. jejuni's ability to metabolize glutamine, glutathione, and asparagine affects its ability to colonize specific host tissues. These findings reflect the emerging theme of bacterial physiology directly impacting pathogenesis.

Comparative Analysis of Drosophila melanogaster Gut Microbiota with Respect to Host Strain, Sex, and Age.

PubMed

Han, Gangsik; Lee, Hyo Jung; Jeong, Sang Eun; Jeon, Che Ok; Hyun, Seogang

2017-07-01

Microbiota has a significant impact on the health of the host individual. The complexity of the interactions between mammalian hosts and their microbiota highlights the value of using Drosophila melanogaster as a model organism, because of its relatively simple microbial community and ease of physiological and genetic manipulation. However, highly variable and sometimes inconsistent results regarding the microbiota of D. melanogaster have been reported for host samples collected from different geographical locations; discrepancies that may be because of the inherent physiological conditions of the D. melanogaster host. Here, we conducted a comparative analysis of the gut microbiota of two D. melanogaster laboratory strains, w 1118 and Canton S, with respect to the sex and age of the host, by pyrosequencing of the 16S rRNA gene. In addition to the widespread and abundant commensal bacterial genera Lactobacillus and Acetobacter, we identified Enterococcus and Leuconostoc as major host-strain-specific bacterial genera. The relative proportions of these bacterial genera, and those of the species within each, were found to differ markedly with respect to strain, sex, and age of the host, even though host individuals were reared under the same nutritional conditions. By using various bioinformatic tools, we uncovered several characteristic features of microbiota corresponding to specific categories of the flies: host-sex-bias association of specific bacteria, age-dependent alteration of microbiota across host species and sex, and uniqueness of the microbiota of female w 1118 flies. Our results, thus, help to further our understanding of host-microbe interactions in the D. melanogaster model.

Remote Sensing between Liver and Intestine: Importance of Microbial Metabolites

PubMed Central

Fu, Zidong Donna; Cui, Julia Yue

2017-01-01

Recent technological advancements including metagenomics sequencing and metabolomics have allowed the discovery of critical functions of gut microbiota in obesity, malnutrition, neurological disorders, asthma, and xenobiotic metabolism. Classification of the human gut microbiome into distinct “enterotypes” has been proposed to serve as a new paradigm for understanding the interplay between microbial variation and human disease phenotypes, as many organs are affected by gut microbiota modifications during the pathogenesis of diseases. Gut microbiota remotely interacts with liver and other metabolic organs of the host through various microbial metabolites that are absorbed into the systemic circulation. Purpose of review The present review summarizes recent literature regarding the importance of gut microbiota in modulating the physiological and pathological responses of various host organs, and describes the functions of the known microbial metabolites that are involved in this remote sensing process, with a primary focus on the gut microbiota-liver axis. Recent findings Under physiological conditions, gut microbiota modulates the hepatic transcriptome, proteome, and metabolome, most notably down-regulating cytochrome P450 3a mediated xenobiotic metabolism. Gut microbiome also modulates the rhythmicity in liver gene expression, likely through microbial metabolites, such as butyrate and propionate that serve as epigenetic modifiers. Additionally, the production of host hormones such as primary bile acids and glucagon like peptide 1 is altered by gut microbiota to modify intermediary metabolism of the host. Summary Dysregulation of gut microbiota is implicated in various liver diseases such as alcoholic liver disease, non-alcoholic steatohepatitis, liver cirrhosis, cholangitis, and liver cancer. Gut microbiota modifiers such as probiotics and prebiotics are increasingly recognized as novel therapeutic modalities for liver and other types of human diseases. PMID:28983453

Gut Microbiota in Cardiovascular Health and Disease

PubMed Central

Tang, W.H. Wilson; Kitai, Takeshi; Hazen, Stanley L

2017-01-01

Significant interest in recent years has focused on gut microbiota-host interaction because accumulating evidence has revealed that intestinal microbiota play an important role in human health and disease, including cardiovascular diseases. Changes in the composition of gut microbiota associated with disease, referred to as dysbiosis, have been linked to pathologies such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity and type 2 diabetes mellitus. In addition to alterations in gut microbiota composition, the metabolic potential of gut microbiota has been identified as a contributing factor in the development of diseases. Recent studies revealed that gut microbiota can elicit a variety of effects on the host. Indeed, the gut microbiome functions like an endocrine organ, generating bioactive metabolites, that can impact host physiology. Microbiota interact with the host through a number of pathways, including the trimethylamine (TMA)/ trimethylamine N-oxide (TMAO) pathway, short-chain fatty acids pathway, and primary and secondary bile acids pathways. In addition to these “metabolism dependent” pathways, metabolism independent processes are suggested to also potentially contribute to CVD pathogenesis. For example, heart failure associated splanchnic circulation congestion, bowel wall edema and impaired intestinal barrier function are thought to result in bacterial translocation, the presence of bacterial products in the systemic circulation and heightened inflammatory state. These are believed to also contribute to further progression of heart failure and atherosclerosis. The purpose of the current review is to highlight the complex interplay between microbiota, their metabolites and the development and progression of cardiovascular diseases. We will also discuss the roles of gut microbiota in normal physiology and the potential of modulating intestinal microbial inhabitants as novel therapeutic targets. PMID:28360349

Gut Microbiota in Cardiovascular Health and Disease.

PubMed

Tang, W H Wilson; Kitai, Takeshi; Hazen, Stanley L

2017-03-31

Significant interest in recent years has focused on gut microbiota-host interaction because accumulating evidence has revealed that intestinal microbiota play an important role in human health and disease, including cardiovascular diseases. Changes in the composition of gut microbiota associated with disease, referred to as dysbiosis, have been linked to pathologies such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus. In addition to alterations in gut microbiota composition, the metabolic potential of gut microbiota has been identified as a contributing factor in the development of diseases. Recent studies revealed that gut microbiota can elicit a variety of effects on the host. Indeed, the gut microbiome functions like an endocrine organ, generating bioactive metabolites, that can impact host physiology. Microbiota interact with the host through many pathways, including the trimethylamine/trimethylamine N -oxide pathway, short-chain fatty acids pathway, and primary and secondary bile acids pathways. In addition to these metabolism-dependent pathways, metabolism-independent processes are suggested to also potentially contribute to cardiovascular disease pathogenesis. For example, heart failure-associated splanchnic circulation congestion, bowel wall edema, and impaired intestinal barrier function are thought to result in bacterial translocation, the presence of bacterial products in the systemic circulation and heightened inflammatory state. These are thought to also contribute to further progression of heart failure and atherosclerosis. The purpose of the current review is to highlight the complex interplay between microbiota, their metabolites, and the development and progression of cardiovascular diseases. We will also discuss the roles of gut microbiota in normal physiology and the potential of modulating intestinal microbial inhabitants as novel therapeutic targets. © 2017 American Heart Association, Inc.

Response of Holobiont Compartments to Salinity Changes Indicates Osmoregulation of Scleractinian Corals

NASA Astrophysics Data System (ADS)

Roethig, T.; Ochsenkuehn, M. A.; van der Merwe, R.; Roik, A.; Voolstra, C. R.

2016-02-01

Environmental change is expected to render the oceans more saline, but scleractinian corals are assumed to be stenohaline osmoconformers. Yet, some corals are able to tolerate salinities up to 50 PSU, but we know little about the mechanisms involved. Previous studies have exclusively addressed the coral host and their algal symbionts (Symbiodinium) in hospite. To disentangle the role of all compartments of the coral holobiont we assessed the response of the coral host, its symbiont algae in the genus Symbiodinium (in hospite and in culture), and the associated bacterial community to strongly increased salinities. In a short-term incubation (4h) we could measure decreases in the calcification rate of the coral host and the photosynthetic performance of its algal symbiont in hospite. In a long-term (29 days) setup we found no differences in the photosynthetic efficiency but a major restructuring of the bacterial communities. In four Symbiodinium cultures we identified changes in photosynthetic yields and osmolytes composition upon short-term salinity exposure (≤24h). Our results show a short-term reaction of coral host and Symbiodinium to strongly increased salinities. However, lack of an apparent physiological long-term response indicates an acclimation process that is accompanied by a microbiome community shift towards a microbiome that potentially supports increased osmolyte production. Furthermore, changes in osmolytes composition in the Symbiodinium cultures display conserved osmoregulatory processes that may translate to osmoregulation for the coral holobiont.

Serine Proteases-Like Genes in the Asian Rice Gall Midge Show Differential Expression in Compatible and Incompatible Interactions with Rice

PubMed Central

Sinha, Deepak Kumar; Lakshmi, Mulagondla; Anuradha, Ghanta; Rahman, Shaik J.; Siddiq, Ebrahimali A.; Bentur, Jagadish S.; Nair, Suresh

2011-01-01

The Asian rice gall midge, Orseolia oryzae (Wood-Mason), is a serious pest of rice. Investigations into the gall midge-rice interaction will unveil the underlying molecular mechanisms which, in turn, can be used as a tool to assist in developing suitable integrated pest management strategies. The insect gut is known to be involved in various physiological and biological processes including digestion, detoxification and interaction with the host. We have cloned and identified two genes, OoprotI and OoprotII, homologous to serine proteases with the conserved His87, Asp136 and Ser241 residues. OoProtI shared 52.26% identity with mosquito-type trypsin from Hessian fly whereas OoProtII showed 52.49% identity to complement component activated C1s from the Hessian fly. Quantitative real time PCR analysis revealed that both the genes were significantly upregulated in larvae feeding on resistant cultivar than in those feeding on susceptible cultivar. These results provide an opportunity to understand the gut physiology of the insect under compatible or incompatible interactions with the host. Phylogenetic analysis grouped these genes in the clade containing proteases of phytophagous insects away from hematophagous insects. PMID:21686154

Epithelial-mesenchymal transition in tissue repair and fibrosis.

PubMed

Stone, Rivka C; Pastar, Irena; Ojeh, Nkemcho; Chen, Vivien; Liu, Sophia; Garzon, Karen I; Tomic-Canic, Marjana

2016-09-01

The epithelial-mesenchymal transition (EMT) describes the global process by which stationary epithelial cells undergo phenotypic changes, including the loss of cell-cell adhesion and apical-basal polarity, and acquire mesenchymal characteristics that confer migratory capacity. EMT and its converse, MET (mesenchymal-epithelial transition), are integral stages of many physiologic processes and, as such, are tightly coordinated by a host of molecular regulators. Converging lines of evidence have identified EMT as a component of cutaneous wound healing, during which otherwise stationary keratinocytes (the resident skin epithelial cells) migrate across the wound bed to restore the epidermal barrier. Moreover, EMT plays a role in the development of scarring and fibrosis, as the matrix-producing myofibroblasts arise from cells of the epithelial lineage in response to injury but are pathologically sustained instead of undergoing MET or apoptosis. In this review, we summarize the role of EMT in physiologic repair and pathologic fibrosis of tissues and organs. We conclude that further investigation into the contribution of EMT to the faulty repair of fibrotic wounds might identify components of EMT signaling as common therapeutic targets for impaired healing in many tissues. Graphical Abstract Model for injury-triggered EMT activation in physiologic wound repair (left) and fibrotic wound healing (right).

Glucose-Induced Trophic Shift in an Endosymbiont Dinoflagellate with Physiological and Molecular Consequences1[OPEN

PubMed Central

Jinkerson, Robert E.; Clowez, Sophie; Onishi, Masayuki; Cleves, Phillip A.; Pringle, John R.

2018-01-01

Interactions between the dinoflagellate endosymbiont Symbiodinium and its cnidarian hosts (e.g. corals, sea anemones) are the foundation of coral-reef ecosystems. Carbon flow between the partners is a hallmark of this mutualism, but the mechanisms governing this flow and its impact on symbiosis remain poorly understood. We showed previously that although Symbiodinium strain SSB01 can grow photoautotrophically, it can grow mixotrophically or heterotrophically when supplied with Glc, a metabolite normally transferred from the alga to its host. Here we show that Glc supplementation of SSB01 cultures causes a loss of pigmentation and photosynthetic activity, disorganization of thylakoid membranes, accumulation of lipid bodies, and alterations of cell-surface morphology. We used global transcriptome analyses to determine if these physiological changes were correlated with changes in gene expression. Glc-supplemented cells exhibited a marked reduction in levels of plastid transcripts encoding photosynthetic proteins, although most nuclear-encoded transcripts (including those for proteins involved in lipid synthesis and formation of the extracellular matrix) exhibited little change in their abundances. However, the altered carbon metabolism in Glc-supplemented cells was correlated with modest alterations (approximately 2x) in the levels of some nuclear-encoded transcripts for sugar transporters. Finally, Glc-bleached SSB01 cells appeared unable to efficiently populate anemone larvae. Together, these results suggest links between energy metabolism and cellular physiology, morphology, and symbiotic interactions. However, the results also show that in contrast to many other organisms, Symbiodinium can undergo dramatic physiological changes that are not reflected by major changes in the abundances of nuclear-encoded transcripts and thus presumably reflect posttranscriptional regulatory processes. PMID:29217594

How host regulation of Helicobacter pylori-induced gastritis protects against peptic ulcer disease and gastric cancer.

PubMed

Dhar, Poshmaal; Ng, Garrett Z; Sutton, Philip

2016-09-01

The bacterial pathogen Helicobacter pylori is the etiological agent of a range of gastrointestinal pathologies including peptic ulcer disease and the major killer, gastric adenocarcinoma. Infection with this bacterium induces a chronic inflammatory response in the gastric mucosa (gastritis). It is this gastritis that, over decades, eventually drives the development of H. pylori-associated disease in some individuals. The majority of studies investigating H. pylori pathogenesis have focused on factors that promote disease development in infected individuals. However, an estimated 85% of those infected with H. pylori remain completely asymptomatic, despite the presence of pathogenic bacteria that drive a chronic gastritis that lasts many decades. This indicates the presence of highly effective regulatory processes in the host that, in most cases, keeps a check on inflammation and protect against disease. In this minireview we discuss such known host factors and how they prevent the development of H. pylori-associated pathologies. Copyright © 2016 the American Physiological Society.

Nutrition acquisition strategies during fungal infection of plants.

PubMed

Divon, Hege H; Fluhr, Robert

2007-01-01

In host-pathogen interactions, efficient pathogen nutrition is a prerequisite for successful colonization and fungal fitness. Filamentous fungi have a remarkable capability to adapt and exploit the external nutrient environment. For phytopathogenic fungi, this asset has developed within the context of host physiology and metabolism. The understanding of nutrient acquisition and pathogen primary metabolism is of great importance in the development of novel disease control strategies. In this review, we discuss the current knowledge on how plant nutrient supplies are utilized by phytopathogenic fungi, and how these activities are controlled. The generation and use of auxotrophic mutants have been elemental to the determination of essential and nonessential nutrient compounds from the plant. Considerable evidence indicates that pathogen entrainment of host metabolism is a widespread phenomenon and can be accomplished by rerouting of the plant's responses. Crucial fungal signalling components for nutrient-sensing pathways as well as their developmental dependency have now been identified, and were shown to operate in a coordinate cross-talk fashion that ensures proper nutrition-related behaviour during the infection process.

Update on Legionnaires’ disease: pathogenesis, epidemiology, detection and control

PubMed Central

Hilbi, Hubert; Jarraud, Sophie; Hartland, Elizabeth; Buchrieser, Carmen

2010-01-01

Summary Legionellosis or Legionnaires’ disease is an emerging and often-fatal form of pneumonia that is most severe in elderly and immunocompromised people, an ever-increasing risk group for infection. In recent years, the genomics of Legionella spp. has significantly increased our knowledge of the pathogenesis of this disease by providing new insights into the evolution and genetic and physiological basis of Legionella–host interactions. The 7th international conference on Legionella, Legionella 2009, illustrated many recent conceptual advances in epidemiology, pathogenesis and ecology. Experts in different fields presented new findings on basic mechanisms of pathogen–host interactions and bacterial evolution, as well as the clinical management and environmental prevalence and persistence of Legionella. The presentations revealed remarkable facts about the genetic and metabolic basis of the intracellular lifestyle of Legionella and reported on its striking ability to manipulate host cell processes by molecular mimicry. Together, these investigations will lead to new approaches for the treatment and prevention of Legionnaires’ disease. PMID:20149105

Investigating Bacterial-Animal Symbioses with Light Sheet Microscopy

PubMed Central

Taormina, Michael J.; Jemielita, Matthew; Stephens, W. Zac; Burns, Adam R.; Troll, Joshua V.; Parthasarathy, Raghuveer; Guillemin, Karen

2014-01-01

SUMMARY Microbial colonization of the digestive tract is a crucial event in vertebrate development, required for maturation of host immunity and establishment of normal digestive physiology. Advances in genomic, proteomic, and metabolomic technologies are providing a more detailed picture of the constituents of the intestinal habitat, but these approaches lack the spatial and temporal resolution needed to characterize the assembly and dynamics of microbial communities in this complex environment. We report the use of light sheet microscopy to provide high resolution imaging of bacterial colonization of the zebrafish intestine. The methodology allows us to characterize bacterial population dynamics across the entire organ and the behaviors of individual bacterial and host cells throughout the colonization process. The large four-dimensional datasets generated by these imaging approaches require new strategies for image analysis. When integrated with other “omics” datasets, information about the spatial and temporal dynamics of microbial cells within the vertebrate intestine will provide new mechanistic insights into how microbial communities assemble and function within hosts. PMID:22983029

Human gut microbiota: does diet matter?

PubMed

Maukonen, Johanna; Saarela, Maria

2015-02-01

The human oro-gastrointestinal (GI) tract is a complex system, consisting of oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine, rectum and anus, which all together with the accessory digestive organs constitute the digestive system. The function of the digestive system is to break down dietary constituents into small molecules and then absorb these for subsequent distribution throughout the body. Besides digestion and carbohydrate metabolism, the indigenous microbiota has an important influence on host physiological, nutritional and immunological processes, and commensal bacteria are able to modulate the expression of host genes that regulate diverse and fundamental physiological functions. The main external factors that can affect the composition of the microbial community in generally healthy adults include major dietary changes and antibiotic therapy. Changes in some selected bacterial groups have been observed due to controlled changes to the normal diet e.g. high-protein diet, high-fat diet, prebiotics, probiotics and polyphenols. More specifically, changes in the type and quantity of non-digestible carbohydrates in the human diet influence both the metabolic products formed in the lower regions of the GI tract and the bacterial populations detected in faeces. The interactions between dietary factors, gut microbiota and host metabolism are increasingly demonstrated to be important for maintaining homeostasis and health. Therefore the aim of this review is to summarise the effect of diet, and especially dietary interventions, on the human gut microbiota. Furthermore, the most important confounding factors (methodologies used and intrinsic human factors) in relation to gut microbiota analyses are elucidated.

Parasitic plants in agriculture: Chemical ecology of germination and host-plant location as targets for sustainable control: A review

Treesearch

Justin B. Runyon; John F. Tooker; Mark C. Mescher; Consuelo M. De Moraes

2009-01-01

Parasitic plants are among the most problematic pests of agricultural crops worldwide. Effective means of control are generally lacking, in part because of the close physiological connection between the established parasite and host plant hindering efficient control using traditional methods. Seed germination and host location are critical early-growth stages that...

Spatial and host-associated variation in prevalence and population density of wheat curl mite (Aceria tosichella) cryptic genotypes in agricultural landscapes

USDA-ARS?s Scientific Manuscript database

The wheat curl mite (WCM), Aceria tosichella Keifer, is a major pest of cereals worldwide that also comprises a complex of at least 16 genetic lineages with divergent physiological traits, including host preference and specificity. The goal of this study was to test the extent to which host-plant sp...

Hormonal and transcriptional profiles highlight common and differential host responses to arbuscular mycorrhizal fungi and the regulation of the oxylipin pathway

PubMed Central

López-Ráez, Juan A.; Verhage, Adriaan; Fernández, Iván; García, Juan M.; Azcón-Aguilar, Concepción; Flors, Victor; Pozo, María J.

2010-01-01

Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. The symbiosis significantly affects the host physiology in terms of nutrition and stress resistance. Despite the lack of host range specificity of the interaction, functional diversity between AM fungal species exists. The interaction is finely regulated according to plant and fungal characters, and plant hormones are believed to orchestrate the modifications in the host plant. Using tomato as a model, an integrative analysis of the host response to different mycorrhizal fungi was performed combining multiple hormone determination and transcriptional profiling. Analysis of ethylene-, abscisic acid-, salicylic acid-, and jasmonate-related compounds evidenced common and divergent responses of tomato roots to Glomus mosseae and Glomus intraradices, two fungi differing in their colonization abilities and impact on the host. Both hormonal and transcriptional analyses revealed, among others, regulation of the oxylipin pathway during the AM symbiosis and point to a key regulatory role for jasmonates. In addition, the results suggest that specific responses to particular fungi underlie the differential impact of individual AM fungi on plant physiology, and particularly on its ability to cope with biotic stresses. PMID:20378666

Emulating Host-Microbiome Ecosystem of Human Gastrointestinal Tract in Vitro.

PubMed

Park, Gun-Seok; Park, Min Hee; Shin, Woojung; Zhao, Connie; Sheikh, Sameer; Oh, So Jung; Kim, Hyun Jung

2017-06-01

The human gut microbiome performs prodigious physiological functions such as production of microbial metabolites, modulation of nutrient digestion and drug metabolism, control of immune system, and prevention of infection. Paradoxically, gut microbiome can also negatively orchestrate the host responses in diseases or chronic disorders, suggesting that the regulated and balanced host-gut microbiome crosstalk is a salient prerequisite in gastrointestinal physiology. To understand the pathophysiological role of host-microbiome crosstalk, it is critical to recreate in vivo relevant models of the host-gut microbiome ecosystem in human. However, controlling the multi-species microbial communities and their uncontrolled growth has remained a notable technical challenge. Furthermore, conventional two-dimensional (2D) or 3D culture systems do not recapitulate multicellular microarchitectures, mechanical dynamics, and tissue-specific functions. Here, we review recent advances and current pitfalls of in vitro and ex vivo models that display human GI functions. We also discuss how the disruptive technologies such as 3D organoids or a human organ-on-a-chip microphysiological system can contribute to better emulate host-gut microbiome crosstalks in health and disease. Finally, the medical and pharmaceutical significance of the gut microbiome-based personalized interventions is underlined as a future perspective.

Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus

DOE PAGES

Howard-Varona, Cristina; Roux, Simon; Dore, Hugo; ...

2016-05-17

Microbes impact human health and disease, industrial processes and natural ecosystems, but do so under the influence of viruses. Problematically, knowledge of viral infection efficiencies and outcomes (e.g. lysis, lysogeny) derives from few model systems that over-represent efficient, lytic infections and under-represent virus-host natural diversity. Here we sought to understand how infection efficiency is regulated in an environmental Bacteroidetes virus that represents a globally abundant viral group and has drastically different infection efficiencies when infecting two nearly identical bacterial strains. To this end, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout the infection of bothmore » bacterial hosts. While the phage transcriptome was similar during both infections, host transcriptional differences appeared to have altered infection efficiency. Specifically, host transcriptomes suggested that the phage failed to repress early host expression in the inefficient nfection, thereby allowing the host to respond against infection by delaying phage DNA replication and protein translation. Further measurements showed that phage DNA and particle production were delayed (by >30 minutes) and reduced (by >50%) in the inefficient versus efficient infection as the host over-expressed DNA degradation genes and under-expressed translation genes, respectively. Together these results suggest that multiple levels of regulation can impact infection efficiencies as failure to repress host transcription allowed the host to defend against both phage DNA and protein production. Given that this phage type is ubiquitous and abundant in the global oceans and that variably efficient viral infections are likely common in any ecosystem with varying phage-host abundances and physiological states, these data provide a critically needed foundation for understanding and modeling viral infection efficiency in nature.« less

Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard-Varona, Cristina; Roux, Simon; Dore, Hugo

Microbes impact human health and disease, industrial processes and natural ecosystems, but do so under the influence of viruses. Problematically, knowledge of viral infection efficiencies and outcomes (e.g. lysis, lysogeny) derives from few model systems that over-represent efficient, lytic infections and under-represent virus-host natural diversity. Here we sought to understand how infection efficiency is regulated in an environmental Bacteroidetes virus that represents a globally abundant viral group and has drastically different infection efficiencies when infecting two nearly identical bacterial strains. To this end, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout the infection of bothmore » bacterial hosts. While the phage transcriptome was similar during both infections, host transcriptional differences appeared to have altered infection efficiency. Specifically, host transcriptomes suggested that the phage failed to repress early host expression in the inefficient nfection, thereby allowing the host to respond against infection by delaying phage DNA replication and protein translation. Further measurements showed that phage DNA and particle production were delayed (by >30 minutes) and reduced (by >50%) in the inefficient versus efficient infection as the host over-expressed DNA degradation genes and under-expressed translation genes, respectively. Together these results suggest that multiple levels of regulation can impact infection efficiencies as failure to repress host transcription allowed the host to defend against both phage DNA and protein production. Given that this phage type is ubiquitous and abundant in the global oceans and that variably efficient viral infections are likely common in any ecosystem with varying phage-host abundances and physiological states, these data provide a critically needed foundation for understanding and modeling viral infection efficiency in nature.« less

Mechanisms and use of neural transplants for brain repair.

PubMed

Dunnett, Stephen B; Björklund, Anders

2017-01-01

Under appropriate conditions, neural tissues transplanted into the adult mammalian brain can survive, integrate, and function so as to influence the behavior of the host, opening the prospect of repairing neuronal damage, and alleviating symptoms associated with neuronal injury or neurodegenerative disease. Alternative mechanisms of action have been postulated: nonspecific effects of surgery; neurotrophic and neuroprotective influences on disease progression and host plasticity; diffuse or locally regulated pharmacological delivery of deficient neurochemicals, neurotransmitters, or neurohormones; restitution of the neuronal and glial environment necessary for proper host neuronal support and processing; promoting local and long-distance host and graft axon growth; formation of reciprocal connections and reconstruction of local circuits within the host brain; and up to full integration and reconstruction of fully functional host neuronal networks. Analysis of neural transplants in a broad range of anatomical systems and disease models, on simple and complex classes of behavioral function and information processing, have indicated that all of these alternative mechanisms are likely to contribute in different circumstances. Thus, there is not a single or typical mode of graft function; rather grafts can and do function in multiple ways, specific to each particular context. Consequently, to develop an effective cell-based therapy, multiple dimensions must be considered: the target disease pathogenesis; the neurodegenerative basis of each type of physiological dysfunction or behavioral symptom; the nature of the repair required to alleviate or remediate the functional impairments of particular clinical relevance; and identification of a suitable cell source or delivery system, along with the site and method of implantation, that can achieve the sought for repair and recovery. © 2017 Elsevier B.V. All rights reserved.

Hepatitis B virus molecular biology and pathogenesis.

PubMed

Lamontagne, R Jason; Bagga, Sumedha; Bouchard, Michael J

2016-01-01

As obligate intracellular parasites, viruses need a host cell to provide a milieu favorable to viral replication. Consequently, viruses often adopt mechanisms to subvert host cellular signaling processes. While beneficial for the viral replication cycle, virus-induced deregulation of host cellular signaling processes can be detrimental to host cell physiology and can lead to virus-associated pathogenesis, including, for oncogenic viruses, cell transformation and cancer progression. Included among these oncogenic viruses is the hepatitis B virus (HBV). Despite the availability of an HBV vaccine, 350-500 million people worldwide are chronically infected with HBV, and a significant number of these chronically infected individuals will develop hepatocellular carcinoma (HCC). Epidemiological studies indicate that chronic infection with HBV is the leading risk factor for the development of HCC. Globally, HCC is the second highest cause of cancer-associated deaths, underscoring the need for understanding mechanisms that regulate HBV replication and the development of HBV-associated HCC. HBV is the prototype member of the Hepadnaviridae family; members of this family of viruses have a narrow host range and predominately infect hepatocytes in their respective hosts. The extremely small and compact hepadnaviral genome, the unique arrangement of open reading frames, and a replication strategy utilizing reverse transcription of an RNA intermediate to generate the DNA genome are distinguishing features of the Hepadnaviridae . In this review, we provide a comprehensive description of HBV biology, summarize the model systems used for studying HBV infections, and highlight potential mechanisms that link a chronic HBV-infection to the development of HCC. For example, the HBV X protein (HBx), a key regulatory HBV protein that is important for HBV replication, is thought to play a cofactor role in the development of HBV-induced HCC, and we highlight the functions of HBx that may contribute to the development of HBV-associated HCC.

Phosphoproteomics in bacteria: towards a systemic understanding of bacterial phosphorylation networks.

PubMed

Jers, Carsten; Soufi, Boumediene; Grangeasse, Christophe; Deutscher, Josef; Mijakovic, Ivan

2008-08-01

Bacteria use protein phosphorylation to regulate all kinds of physiological processes. Protein phosphorylation plays a role in several key steps of the infection process of bacterial pathogens, such as adhesion to the host, triggering and regulation of pathogenic functions as well as biochemical warfare; scrambling the host signaling cascades and impairing its defense mechanisms. Recent phosphoproteomic studies indicate that the bacterial protein phosphorylation networks could be more complex than initially expected, comprising promiscuous kinases that regulate several distinct cellular functions by phosphorylating different protein substrates. Recent advances in protein labeling with stable isotopes in the field of quantitative mass spectrometry phosphoproteomics will enable us to chart the global phosphorylation networks and to understand the implication of protein phosphorylation in cellular regulation on the systems scale. For the study of bacterial pathogens, in particular, this research avenue will enable us to dissect phosphorylation-related events during different stages of infection and stimulate our efforts to find inhibitors for key kinases and phosphatases implicated therein.

Misconceptions Highlighted among Medical Students in the Annual International Intermedical School Physiology Quiz

ERIC Educational Resources Information Center

Cheng, Hwee-Ming; Durairajanayagam, Damayanthi

2012-01-01

The annual Intermedical School Physiology Quiz (IMSPQ), initiated in 2003, is now an event that attracts a unique, large gathering of selected medical students from medical schools across the globe. The 8th IMSPQ, in 2010, hosted by the Department of Physiology, University of Malaya, in Kuala Lumpur, Malaysia, had 200 students representing 41…

Protein Discovery: Combined Transcriptomic and Proteomic Analyses of Venom from the Endoparasitoid Cotesia chilonis (Hymenoptera: Braconidae)

PubMed Central

Teng, Zi-Wen; Xiong, Shi-Jiao; Xu, Gang; Gan, Shi-Yu; Chen, Xuan; Stanley, David; Yan, Zhi-Chao; Ye, Gong-Yin; Fang, Qi

2017-01-01

Many species of endoparasitoid wasps provide biological control services in agroecosystems. Although there is a great deal of information on the ecology and physiology of host/parasitoid interactions, relatively little is known about the protein composition of venom and how specific venom proteins influence physiological systems within host insects. This is a crucial gap in our knowledge because venom proteins act in modulating host physiology in ways that favor parasitoid development. Here, we identified 37 possible venom proteins from the polydnavirus-carrying endoparasitoid Cotesia chilonis by combining transcriptomic and proteomic analyses. The most abundant proteins were hydrolases, such as proteases, peptidases, esterases, glycosyl hydrolase, and endonucleases. Some components are classical parasitoid venom proteins with known functions, including extracellular superoxide dismutase 3, serine protease inhibitor and calreticulin. The venom contains novel proteins, not recorded from any other parasitoid species, including tolloid-like proteins, chitooligosaccharidolytic β-N-acetylglucosaminidase, FK506-binding protein 14, corticotropin-releasing factor-binding protein and vascular endothelial growth factor receptor 2. These new data generate hypotheses and provide a platform for functional analysis of venom components. PMID:28417942

Proteomic Analysis of Interactions between a Deep-Sea Thermophilic Bacteriophage and Its Host at High Temperature ▿ †

PubMed Central

Wei, Dahai; Zhang, Xiaobo

2010-01-01

The virus-host interaction is essential to understanding the role that viruses play in ecological and geochemical processes in deep-sea vent ecosystems. Virus-induced changes in cellular gene expression and host physiology have been studied extensively. However, the molecular mechanism of interaction between a bacteriophage and its host at high temperature remains poorly understood. In the present study, the virus-induced gene expression profile of Geobacillus sp. E263, a thermophile isolated from a deep-sea hydrothermal ecosystem, was characterized. Based on proteomic analysis and random arbitrarily primed PCR (RAP-PCR) of Geobacillus sp. E263 cultured under non-bacteriophage GVE2 infection and GVE2 infection conditions, there were two types of protein/gene profiles in response to GVE2 infection. Twenty differentially expressed genes and proteins were revealed that could be grouped into 3 different categories based on cellular function, suggesting a coordinated response to infection. These differentially expressed genes and proteins were further confirmed by Northern blot analysis. To characterize the host proteins in response to virus infection, aspartate aminotransferase (AST) was inactivated to construct the AST mutant of Geobacillus sp. E263. The results showed that the AST protein was essential in virus infection. Thus, transcriptional and proteomic analyses and functional analysis revealed previously unknown host responses to deep-sea thermophilic virus infection. PMID:20015994

A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host–Pathogen Interaction Networks

PubMed Central

Wu, Chia-Chou; Chen, Bor-Sen

2016-01-01

Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host–pathogen dynamic interaction networks. The consideration of host–pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host–pathogen molecular interaction networks, and consequent inferences of the host–pathogen relationship could be translated into biomedical applications. PMID:26881892

Physiologically-based kinetic modelling in risk assessment

EPA Science Inventory

The European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) hosted a two-day workshop with an aim to discuss the role and application of Physiologically Based Kinetic (PBK) models in regulatory decision making. The EURL ECVAM strategy document on Toxic...

Carbonic anhydrase 2-like in the giant clam, Tridacna squamosa: characterization, localization, response to light, and possible role in the transport of inorganic carbon from the host to its symbionts.

PubMed

Ip, Yuen K; Koh, Clarissa Z Y; Hiong, Kum C; Choo, Celine Y L; Boo, Mel V; Wong, Wai P; Neo, Mei L; Chew, Shit F

2017-12-01

The fluted giant clam, Tridacna squamosa , lives in symbiosis with zooxanthellae which reside extracellularly inside a tubular system. Zooxanthellae fix inorganic carbon (C i ) during insolation and donate photosynthate to the host. Carbonic anhydrases catalyze the interconversion of CO 2 and HCO3-, of which carbonic anhydrase 2 (CA2) is the most ubiquitous and involved in many biological processes. This study aimed to clone a CA2 homolog ( CA2-like ) from the fleshy and colorful outer mantle as well as the thin and whitish inner mantle of T. squamosa , to determine its cellular and subcellular localization, and to examine the effects of light exposure on its gene and protein expression levels. The cDNA coding sequence of CA2-like from T. squamosa comprised 789 bp, encoding 263 amino acids with an estimated molecular mass of 29.6 kDa. A phenogramic analysis of the deduced CA2-like sequence denoted an animal origin. CA2-like was not detectable in the shell-facing epithelium of the inner mantle adjacent to the extrapallial fluid. Hence, CA2-like is unlikely to participate directly in light-enhanced calcification. By contrast, the outer mantle, which contains the highest density of tertiary tubules and zooxanthellae, displayed high level of CA2-like expression, and CA2-like was localized to the tubule epithelial cells. More importantly, exposure to light induced significant increases in the protein abundance of CA2-like in the outer mantle. Hence, CA2-like could probably take part in the increased supply of inorganic carbon (C i ) from the host clam to the symbiotic zooxanthellae when the latter conduct photosynthesis to fix C i during light exposure. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

The endobacterium of an arbuscular mycorrhizal fungus modulates the expression of its toxin-antitoxin systems during the life cycle of its host.

PubMed

Salvioli di Fossalunga, Alessandra; Lipuma, Justine; Venice, Francesco; Dupont, Laurence; Bonfante, Paola

2017-10-01

Arbuscular mycorrhizal fungi (AMF) are widespread root symbionts that perform important ecological services, such as improving plant nutrient and water acquisition. Some AMF from the Gigasporaceae family host a population of endobacteria, Candidatus Glomeribacter gigasporarum (Cagg). The analysis of the Cagg genome identified six putative toxin-antitoxin modules (TAs), consisting of pairs of stable toxins and unstable antitoxins that affect diverse physiological functions. Sequence analysis suggested that these TA modules were acquired by horizontal transfer. Gene expression patterns of two TAs (yoeB/yefM and chpB/chpS) changed during the fungal life cycle, with the expression during the pre-symbiotic phase higher than during the symbiosis with the plant host. The heterologous expression in Escherichia coli demonstrated the functionality only for the YoeB-YefM pair. On the basis of these observations, we speculate that TA modules might help Cagg adapt to its intracellular habitat, coordinating its proliferation with the physiological state of the AMF host.

Phage phenomics: Physiological approaches to characterize novel viral proteins

ScienceCinema

Sanchez, Savannah E. [San Diego State Univ., San Diego, CA (United States); Cuevas, Daniel A. [San Diego State Univ., San Diego, CA (United States); Rostron, Jason E. [San Diego State Univ., San Diego, CA (United States); Liang, Tiffany Y. [San Diego State Univ., San Diego, CA (United States); Pivaroff, Cullen G. [San Diego State Univ., San Diego, CA (United States); Haynes, Matthew R. [San Diego State Univ., San Diego, CA (United States); Nulton, Jim [San Diego State Univ., San Diego, CA (United States); Felts, Ben [San Diego State Univ., San Diego, CA (United States); Bailey, Barbara A. [San Diego State Univ., San Diego, CA (United States); Salamon, Peter [San Diego State Univ., San Diego, CA (United States); Edwards, Robert A. [San Diego State Univ., San Diego, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Burgin, Alex B. [Broad Institute, Cambridge, MA (United States); Segall, Anca M. [San Diego State Univ., San Diego, CA (United States); Rohwer, Forest [San Diego State Univ., San Diego, CA (United States)

2018-06-21

Current investigations into phage-host interactions are dependent on extrapolating knowledge from (meta)genomes. Interestingly, 60 - 95% of all phage sequences share no homology to current annotated proteins. As a result, a large proportion of phage genes are annotated as hypothetical. This reality heavily affects the annotation of both structural and auxiliary metabolic genes. Here we present phenomic methods designed to capture the physiological response(s) of a selected host during expression of one of these unknown phage genes. Multi-phenotype Assay Plates (MAPs) are used to monitor the diversity of host substrate utilization and subsequent biomass formation, while metabolomics provides bi-product analysis by monitoring metabolite abundance and diversity. Both tools are used simultaneously to provide a phenotypic profile associated with expression of a single putative phage open reading frame (ORF). Thus, representative results for both methods are compared, highlighting the phenotypic profile differences of a host carrying either putative structural or metabolic phage genes. In addition, the visualization techniques and high throughput computational pipelines that facilitated experimental analysis are presented.

Differential outcomes of Zika virus infection in Aedes aegypti orally challenged with infectious blood meals and infectious protein meals.

PubMed

Huang, Yan-Jang S; Lyons, Amy C; Hsu, Wei-Wen; Park, So Lee; Higgs, Stephen; Vanlandingham, Dana L

2017-01-01

Infection of mosquitoes is an essential step for the transmission of mosquito-borne arboviruses in nature. Engorgement of infectious blood meals from viremic infected vertebrate hosts allows the entry of viruses and initiates infection of midgut epithelial cells. Historically, the infection process of arboviruses in mosquitoes has been studied through the engorgement of mosquitoes from viremic laboratory animals or from artificial feeders containing blood mixed with viruses harvested from cell cultures. The latter approach using so-called artificial blood meals is more frequently used since it is readily optimized to maximize viral titer, negates the use of animals and can be used with viruses for which there are no small animal models. Use of artificial blood meals has enabled numerous studies on mosquito infections with a wide variety of viruses; however, as described here, with suitable modification it can also be used to study the interplay between infection, specific blood components, and physiological consequences associated with blood engorgement. For hematophagous female mosquitoes, blood is the primary nutritional source supporting all physiological process including egg development, and also influences neurological processes and behaviors such as host-seeking. Interactions between these blood-driven vector biological processes and arbovirus infection that is mediated via blood engorgement have not yet been specifically studied. This is in part because presentation of virus in whole blood inevitably induces enzymatic digestion processes, hormone driven oogenesis, and other biological changes. In this study, the infection process of Zika virus (ZIKV) in Aedes aegypti was characterized by oral exposure via viral suspension meals within minimally bovine serum albumin complemented medium or within whole blood. The use of bovine serum albumin in infectious meals provides an opportunity to evaluate the role of serum albumin during the process of flavivirus infection in mosquitoes. Infectious whole blood meals and infectious bovine serum albumin meals containing ZIKV were orally presented to two different groups of Ae. aegypti through membrane feeding. At 7 and 14 days post infection, infectious viruses were detected and viral dissemination from gut to other mosquito tissues was analyzed in orally challenged mosquitoes with 50% tissue culture infectious dose method on Vero76 cells. Zika virus infection was significantly impaired among mosquitoes orally challenged with infectious protein meals as compared to infectious whole blood meals. These results indicate the importance of the blood meal in the infection process of arboviruses in mosquitoes. It provides the basis for future studies to identify critical components in the blood of vertebrate hosts that facilitate arbovirus infection in mosquitoes.

Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector

PubMed Central

Maixner, Michael; Albert, Andreas; Johannesen, Jes

2014-01-01

Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan–Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative mating within host races and a reduction in the likelihood of oviposition on the alternative plant and thus the acquisition of alternative stolbur strains. PMID:25247065

Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector.

PubMed

Maixner, Michael; Albert, Andreas; Johannesen, Jes

2014-08-01

Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan-Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative mating within host races and a reduction in the likelihood of oviposition on the alternative plant and thus the acquisition of alternative stolbur strains.

Transcriptomic changes in an animal-bacterial symbiosis under modeled microgravity conditions

PubMed Central

Casaburi, Giorgio; Goncharenko-Foster, Irina; Duscher, Alexandrea A.; Foster, Jamie S.

2017-01-01

Spaceflight imposes numerous adaptive challenges for terrestrial life. The reduction in gravity, or microgravity, represents a novel environment that can disrupt homeostasis of many physiological processes. Additionally, it is becoming increasingly clear that an organism’s microbiome is critical for host health and examining its resiliency in microgravity represents a new frontier for space biology research. In this study, we examine the impact of microgravity on the interactions between the squid Euprymna scolopes and its beneficial symbiont Vibrio fischeri, which form a highly specific binary mutualism. First, animals inoculated with V. fischeri aboard the space shuttle showed effective colonization of the host light organ, the site of the symbiosis, during space flight. Second, RNA-Seq analysis of squid exposed to modeled microgravity conditions exhibited extensive differential gene expression in the presence and absence of the symbiotic partner. Transcriptomic analyses revealed in the absence of the symbiont during modeled microgravity there was an enrichment of genes and pathways associated with the innate immune and oxidative stress response. The results suggest that V. fischeri may help modulate the host stress responses under modeled microgravity. This study provides a window into the adaptive responses that the host animal and its symbiont use during modeled microgravity. PMID:28393904

Significant differences in genotoxicity induced by retrovirus integration in human T cells and induced pluripotent stem cells.

PubMed

Zheng, Weiyan; Wang, Yingjia; Chang, Tammy; Huang, He; Yee, Jiing-Kuan

2013-04-25

Retrovirus is frequently used in the genetic modification of mammalian cells and the establishment of induced pluripotent stem cells (iPSCs) via cell reprogramming. Vector-induced genotoxicity could induce profound effect on the physiology and function of these stem cells and their differentiated progeny. We analyzed retrovirus-induced genotoxicity in somatic cell Jurkat and two iPSC lines. In Jurkat cells, retrovirus frequently activated host gene expression and gene activation was not dependent on the distance between the integration site and the transcription start site of the host gene. In contrast, retrovirus frequently down-regulated host gene expression in iPSCs, possibly due to the action of chromatin silencing that spreads from the provirus to the nearby host gene promoter. Our data raises the issue that some of the phenotypic variability observed among iPSC clones derived from the same parental cell line may be caused by retrovirus-induced gene expression changes rather than by the reprogramming process itself. It also underscores the importance of characterizing retrovirus integration and carrying out risk assessment of iPSCs before they can be applied in basic research and clinics. Copyright © 2013 Elsevier B.V. All rights reserved.

Gut Microbiota: A Contributing Factor to Obesity

PubMed Central

Harakeh, Steve M.; Khan, Imran; Kumosani, Taha; Barbour, Elie; Almasaudi, Saad B.; Bahijri, Suhad M.; Alfadul, Sulaiman M.; Ajabnoor, Ghada M. A.; Azhar, Esam I.

2016-01-01

Obesity, a global epidemic of the modern era, is a risk factor for cardiovascular diseases (CVD) and diabetes. The pervasiveness of obesity and overweight in both developed as well as developing populations is on the rise and placing a huge burden on health and economic resources. Consequently, research to control this emerging epidemic is of utmost importance. Recently, host interactions with their resident gut microbiota (GM) have been reported to be involved in the pathogenesis of many metabolic diseases, including obesity, diabetes, and CVD. Around 1014 microorganisms reside within the lower human intestine and many of these 1014 microorganisms have developed mutualistic or commensal associations with the host and actively involved in many physiological processes of the host. However, dysbiosis (altered gut microbial composition) with other predisposing genetic and environmental factors, may contribute to host metabolic disorders resulting in many ailments. Therefore, delineating the role of GM as a contributing factor to obesity is the main objective of this review. Obesity research, as a field is expanding rapidly due to major advances in nutrigenomics, metabolomics, RNA silencing, epigenetics, and other disciplines that may result in the emergence of new technologies and methods to better interpret causal relationships between microbiota and obesity. PMID:27625997

Microbial communities and bioactive compounds in marine sponges of the family irciniidae-a review.

PubMed

Hardoim, Cristiane C P; Costa, Rodrigo

2014-09-30

Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species-the vast majority of which are difficult to cultivate-and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.

Osmotic regulation of expression of two extracellular matrix-binding proteins and a haemolysin of Leptospira interrogans: differential effects on LigA and Sph2 extracellular release.

PubMed

Matsunaga, James; Medeiros, Marco A; Sanchez, Yolanda; Werneid, Kristian F; Ko, Albert I

2007-10-01

The life cycle of the pathogen Leptospira interrogans involves stages outside and inside the host. Entry of L. interrogans from moist environments into the host is likely to be accompanied by the induction of genes encoding virulence determinants and the concomitant repression of genes encoding products required for survival outside of the host. The expression of the adhesin LigA, the haemolysin Sph2 (Lk73.5) and the outer-membrane lipoprotein LipL36 of pathogenic Leptospira species have been reported to be regulated by mammalian host signals. A previous study demonstrated that raising the osmolarity of the leptospiral growth medium to physiological levels encountered in the host by addition of various salts enhanced the levels of cell-associated LigA and LigB and extracellular LigA. In this study, we systematically examined the effects of osmotic upshift with ionic and non-ionic solutes on expression of the known mammalian host-regulated leptospiral genes. The levels of cell-associated LigA, LigB and Sph2 increased at physiological osmolarity, whereas LipL36 levels decreased, corresponding to changes in specific transcript levels. These changes in expression occurred irrespective of whether sodium chloride or sucrose was used as the solute. The increase of cellular LigA, LigB and Sph2 protein levels occurred within hours of adding sodium chloride. Extracellular Sph2 levels increased when either sodium chloride or sucrose was added to achieve physiological osmolarity. In contrast, enhanced levels of extracellular LigA were observed only with an increase in ionic strength. These results indicate that the mechanisms for release of LigA and Sph2 differ during host infection. Thus, osmolarity not only affects leptospiral gene expression by affecting transcript levels of putative virulence determinants but also affects the release of such proteins into the surroundings.

Distinct Lineages of Schistocephalus Parasites in Threespine and Ninespine Stickleback Hosts Revealed by DNA Sequence Analysis

PubMed Central

Nishimura, Nicole; Heins, David C.; Andersen, Ryan O.; Barber, Iain; Cresko, William A.

2011-01-01

Parasitic interactions are often part of complex networks of interspecific relationships that have evolved in biological communities. Despite many years of work on the evolution of parasitism, the likelihood that sister taxa of parasites can co-evolve with their hosts to specifically infect two related lineages, even when those hosts occur sympatrically, is still unclear. Furthermore, when these specific interactions occur, the molecular and physiological basis of this specificity is still largely unknown. The presence of these specific parasitic relationships can now be tested using molecular markers such as DNA sequence variation. Here we test for specific parasitic relationships in an emerging host-parasite model, the stickleback-Schistocephalus system. Threespine and ninespine stickleback fish are intermediate hosts for Schistocephalus cestode parasites that are phenotypically very similar and have nearly identical life cycles through plankton, stickleback, and avian hosts. We analyzed over 2000 base pairs of COX1 and NADH1 mitochondrial DNA sequences in 48 Schistocephalus individuals collected from threespine and ninespine stickleback hosts from disparate geographic regions distributed across the Northern Hemisphere. Our data strongly support the presence of two distinct clades of Schistocephalus, each of which exclusively infects either threespine or ninespine stickleback. These clades most likely represent different species that diverged soon after the speciation of their stickleback hosts. In addition, genetic structuring exists among Schistocephalus taken from threespine stickleback hosts from Alaska, Oregon and Wales, although it is much less than the divergence between hosts. Our findings emphasize that biological communities may be even more complex than they first appear, and beg the question of what are the ecological, physiological, and genetic factors that maintain the specificity of the Schistocephalus parasites and their stickleback hosts. PMID:21811623

Phytonutrients as non-nutritive feed additives to enhance growth and host immunity in broiler chickens

USDA-ARS?s Scientific Manuscript database

The gut represents a continuously evolving ecosystem where a dynamic interaction between host immune, neuroendocrine and entero-endocrine cells and the gut microbiota influences normal physiological development and homeostasis. New antibiotic regulatory policies and cage-free rearing systems in pou...

The emerging relevance of the gut microbiome in cardiometabolic health

USDA-ARS?s Scientific Manuscript database

Host metabolic pathways and physiological responses are regulated by signals linking the host to the gut microbial community or microbiome. Here, we draw a spotlight on lipid and bile acid metabolism and inflammatory response as they pertain to cardiometabolic dysfunction. Gut microbial dysbiosis al...

Chapter 13. Physiology and ecology of host defense against microbial invaders

USDA-ARS?s Scientific Manuscript database

Insects mount a complex hierarchy of defenses that pathogens must overcome before successful infection is achieved. Behavioral avoidance and antiseptic behaviors by host insects reduce the degree of encounters between the insect and pathogens. Any pathogen that contacts or establishes on a potentia...

Diet and the Intestinal Microbiome: Associations, Functions, and Implications for Health and Disease

PubMed Central

Albenberg, Lindsey G.; Wu, Gary D.

2014-01-01

The mutual relationship between the intestinal microbiota and its mammalian host is influenced by diet. Consumption of various nutrients affects the structure of the microbial community and provides substrates for microbial metabolism. The microbiota can produce small molecules that are absorbed by the host and affect many important physiological processes. Age-dependent and societal differences in the intestinal microbiota could result from differences in diet. Examples include differences in the intestinal microbiota of breast- vs formula-fed infants, or differences in microbial richness in individuals consuming an agrarian plant-based vs a Western diet, which is high in meat and fat. We review how diet affects the structure and metabolome of the human intestinal microbiome, and may contribute to health or pathogenesis of disorders such as coronary vascular disease and inflammatory bowel diseases. PMID:24503132

Influence of halophytic hosts on their parasites—the case of Plicosepalus acaciae

PubMed Central

Veste, Maik; Todt, Henning; Breckle, Siegmar-W.

2015-01-01

Halophytes develop various morphological and physiological traits that enable them to grow successfully on saline substrates. Parasitic plants on halophytic hosts may also encounter salt stress. We investigated the mistletoe Plicosepalus acaciae (syn: Loranthus acacia; Loranthaceae), which occurs on 5 halophytic and at least 10 non-halophytic hosts in the Southern Arava Valley (Israel). Plicosepalus acaciae is a common parasite north of Eilat to the Dead Sea area and in the Jordan Valley. Morphological and physiological responses of P. acaciae to salinity were investigated by comparison of plants on halophytic with those on non-halophytic hosts. Ion patterns of different host–parasite associations were determined as was the development of leaf succulence at different growth stages. The leaf water content of P. acaciae increased and leaves developed succulence when growing on halophytic hosts, especially on Tamarix species, where leaf water content was three times higher than that on non-halophytic hosts and the leaf volume increased four to five times. The reason for increased succulence was a higher ion concentration of, and osmotic adjustment with, Na+ and Cl−. Plicosepalus acaciae showed a high morphological and ecophysiological plasticity, enabling it to cope with salt stress, and can be classified as a facultative eu-halophyte, which increases its halo-succulence according to the host. Host–parasite associations are a model system for the investigation of halophytes under different salt stress conditions. PMID:25515726

Drosophila melanogaster as a High-Throughput Model for Host-Microbiota Interactions.

PubMed

Trinder, Mark; Daisley, Brendan A; Dube, Josh S; Reid, Gregor

2017-01-01

Microbiota research often assumes that differences in abundance and identity of microorganisms have unique influences on host physiology. To test this concept mechanistically, germ-free mice are colonized with microbial communities to assess causation. Due to the cost, infrastructure challenges, and time-consuming nature of germ-free mouse models, an alternative approach is needed to investigate host-microbial interactions. Drosophila melanogaster (fruit flies) can be used as a high throughput in vivo screening model of host-microbiome interactions as they are affordable, convenient, and replicable. D. melanogaster were essential in discovering components of the innate immune response to pathogens. However, axenic D. melanogaster can easily be generated for microbiome studies without the need for ethical considerations. The simplified microbiota structure enables researchers to evaluate permutations of how each microbial species within the microbiota contribute to host phenotypes of interest. This enables the possibility of thorough strain-level analysis of host and microbial properties relevant to physiological outcomes. Moreover, a wide range of mutant D. melanogaster strains can be affordably obtained from public stock centers. Given this, D. melanogaster can be used to identify candidate mechanisms of host-microbe symbioses relevant to pathogen exclusion, innate immunity modulation, diet, xenobiotics, and probiotic/prebiotic properties in a high throughput manner. This perspective comments on the most promising areas of microbiota research that could immediately benefit from using the D. melanogaster model.

Yeast Communities of Diverse Drosophila Species: Comparison of Two Symbiont Groups in the Same Hosts

PubMed Central

Eisen, Jonathan A.; Kopp, Artyom

2012-01-01

The combination of ecological diversity with genetic and experimental tractability makes Drosophila a powerful model for the study of animal-associated microbial communities. Despite the known importance of yeasts in Drosophila physiology, behavior, and fitness, most recent work has focused on Drosophila-bacterial interactions. In order to get a more complete understanding of the Drosophila microbiome, we characterized the yeast communities associated with different Drosophila species collected around the world. We focused on the phylum Ascomycota because it constitutes the vast majority of the Drosophila-associated yeasts. Our sampling strategy allowed us to compare the distribution and structure of the yeast and bacterial communities in the same host populations. We show that yeast communities are dominated by a small number of abundant taxa, that the same yeast lineages are associated with different host species and populations, and that host diet has a greater effect than host species on yeast community composition. These patterns closely parallel those observed in Drosophila bacterial communities. However, we do not detect a significant correlation between the yeast and bacterial communities of the same host populations. Comparative analysis of different symbiont groups provides a more comprehensive picture of host-microbe interactions. Future work on the role of symbiont communities in animal physiology, ecological adaptation, and evolution would benefit from a similarly holistic approach. PMID:22885750

Free-living pathogens: life-history constraints and strain competition.

PubMed

Caraco, Thomas; Wang, Ing-Nang

2008-02-07

Many pathogen life histories include a free-living stage, often with anatomical and physiological adaptations promoting persistence outside of host tissues. More durable particles presumably require that the pathogen metabolize more resources per particle. Therefore, we hypothesize functional dependencies, pleiotropic constraints, between the rate at which free-living particles decay outside of host tissues and other pathogen traits, including virulence, the probability of infecting a host upon contact, and pathogen reproduction within host tissues. Assuming that pathogen strains compete for hosts preemptively, we find patterns in trait dependencies predicting whether or not strain competition favors a highly persistent free-living stage.

Teleosts as Model Organisms To Understand Host-Microbe Interactions.

PubMed

Lescak, Emily A; Milligan-Myhre, Kathryn C

2017-08-01

Host-microbe interactions are influenced by complex host genetics and environment. Studies across animal taxa have aided our understanding of how intestinal microbiota influence vertebrate development, disease, and physiology. However, traditional mammalian studies can be limited by the use of isogenic strains, husbandry constraints that result in small sample sizes and limited statistical power, reliance on indirect characterization of gut microbial communities from fecal samples, and concerns of whether observations in artificial conditions are actually reflective of what occurs in the wild. Fish models are able to overcome many of these limitations. The extensive variation in the physiology, ecology, and natural history of fish enriches studies of the evolution and ecology of host-microbe interactions. They share physiological and immunological features common among vertebrates, including humans, and harbor complex gut microbiota, which allows identification of the mechanisms driving microbial community assembly. Their accelerated life cycles and large clutch sizes and the ease of sampling both internal and external microbial communities make them particularly well suited for robust statistical studies of microbial diversity. Gnotobiotic techniques, genetic manipulation of the microbiota and host, and transparent juveniles enable novel insights into mechanisms underlying development of the digestive tract and disease states. Many diseases involve a complex combination of genes which are difficult to manipulate in homogeneous model organisms. By taking advantage of the natural genetic variation found in wild fish populations, as well as of the availability of powerful genetic tools, future studies should be able to identify conserved genes and pathways that contribute to human genetic diseases characterized by dysbiosis. Copyright © 2017 Lescak and Milligan-Myhre.

Teleosts as Model Organisms To Understand Host-Microbe Interactions

PubMed Central

2017-01-01

ABSTRACT Host-microbe interactions are influenced by complex host genetics and environment. Studies across animal taxa have aided our understanding of how intestinal microbiota influence vertebrate development, disease, and physiology. However, traditional mammalian studies can be limited by the use of isogenic strains, husbandry constraints that result in small sample sizes and limited statistical power, reliance on indirect characterization of gut microbial communities from fecal samples, and concerns of whether observations in artificial conditions are actually reflective of what occurs in the wild. Fish models are able to overcome many of these limitations. The extensive variation in the physiology, ecology, and natural history of fish enriches studies of the evolution and ecology of host-microbe interactions. They share physiological and immunological features common among vertebrates, including humans, and harbor complex gut microbiota, which allows identification of the mechanisms driving microbial community assembly. Their accelerated life cycles and large clutch sizes and the ease of sampling both internal and external microbial communities make them particularly well suited for robust statistical studies of microbial diversity. Gnotobiotic techniques, genetic manipulation of the microbiota and host, and transparent juveniles enable novel insights into mechanisms underlying development of the digestive tract and disease states. Many diseases involve a complex combination of genes which are difficult to manipulate in homogeneous model organisms. By taking advantage of the natural genetic variation found in wild fish populations, as well as of the availability of powerful genetic tools, future studies should be able to identify conserved genes and pathways that contribute to human genetic diseases characterized by dysbiosis. PMID:28439034

Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree-ring C and O stable isotopes

Treesearch

D. E. Marias; F. C. Meinzer; D. R. Woodruff; D. C. Shaw; S. L. Voelker; Steven W. Oak; William J. Otrosina; William D. Smith; Kamal J.K. Gandhi

2014-01-01

Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture and photosynthetic gas exchange and can eventually induce tree death. To investigate the long-term (1886–2010) impacts of dwarf mistletoe on the growth and gas exchange characteristics of host western hemlock, we...

Stress hormones predict a host superspreader phenotype in the West Nile virus system

USGS Publications Warehouse

Gervasi, Stephanie; Burgan, Sarah; Hofmeister, Erik K.; Unnasch, Thomas R.; Martin, Lynn B.

2017-01-01

Glucocorticoid stress hormones, such as corticosterone (CORT), have profound effects on the behaviour and physiology of organisms, and thus have the potential to alter host competence and the contributions of individuals to population- and community-level pathogen dynamics. For example, CORT could alter the rate of contacts among hosts, pathogens and vectors through its widespread effects on host metabolism and activity levels. CORT could also affect the intensity and duration of pathogen shedding and risk of host mortality during infection. We experimentally manipulated songbird CORT, asking how CORT affected behavioural and physiological responses to a standardized West Nile virus (WNV) challenge. Although all birds became infected after exposure to the virus, only birds with elevated CORT had viral loads at or above the infectious threshold. Moreover, though the rate of mortality was faster in birds with elevated CORT compared with controls, most hosts with elevated CORT survived past the day of peak infectiousness. CORT concentrations just prior to inoculation with WNV and anti-inflammatory cytokine concentrations following viral exposure were predictive of individual duration of infectiousness and the ability to maintain physical performance during infection (i.e. tolerance), revealing putative biomarkers of competence. Collectively, our results suggest that glucocorticoid stress hormones could directly and indirectly mediate the spread of pathogens.

Ecophysiology meets conservation: understanding the role of disease in amphibian population declines

PubMed Central

Blaustein, Andrew R.; Gervasi, Stephanie S.; Johnson, Pieter T. J.; Hoverman, Jason T.; Belden, Lisa K.; Bradley, Paul W.; Xie, Gisselle Y.

2012-01-01

Infectious diseases are intimately associated with the dynamics of biodiversity. However, the role that infectious disease plays within ecological communities is complex. The complex effects of infectious disease at the scale of communities and ecosystems are driven by the interaction between host and pathogen. Whether or not a given host–pathogen interaction results in progression from infection to disease is largely dependent on the physiological characteristics of the host within the context of the external environment. Here, we highlight the importance of understanding the outcome of infection and disease in the context of host ecophysiology using amphibians as a model system. Amphibians are ideal for such a discussion because many of their populations are experiencing declines and extinctions, with disease as an important factor implicated in many declines and extinctions. Exposure to pathogens and the host's responses to infection can be influenced by many factors related to physiology such as host life history, immunology, endocrinology, resource acquisition, behaviour and changing climates. In our review, we discuss the relationship between disease and biodiversity. We highlight the dynamics of three amphibian host–pathogen systems that induce different effects on hosts and life stages and illustrate the complexity of amphibian–host–parasite systems. We then review links between environmental stress, endocrine–immune interactions, disease and climate change. PMID:22566676

Emerging Infections of CNS: Avian Influenza A Virus, Rift Valley Fever Virus and Human Parechovirus.

PubMed

Wiley, Clayton A; Bhardwaj, Nitin; Ross, Ted M; Bissel, Stephanie J

2015-09-01

History is replete with emergent pandemic infections that have decimated the human population. Given the shear mass of humans that now crowd the earth, there is every reason to suspect history will repeat itself. We describe three RNA viruses that have recently emerged in the human population to mediate severe neurological disease. These new diseases are results of new mutations in the infectious agents or new exposure pathways to the agents or both. To appreciate their pathogenesis, we summarize the essential virology and immune response to each agent. Infection is described in the context of known host defenses. Once the viruses evade immune defenses and enter central nervous system (CNS) cells, they rapidly co-opt host RNA processing to a cataclysmic extent. It is not clear why the brain is particularly susceptible to RNA viruses; but perhaps because of its tremendous dependence on RNA processing for physiological functioning, classical mechanisms of host defense (eg, interferon disruption of viral replication) are diminished or not available. Effectiveness of immunity, immunization and pharmacological therapies is reviewed to contextualize the scope of the public health challenge. Unfortunately, vaccines that confer protection from systemic disease do not necessarily confer protection for the brain after exposure through unconventional routes. © 2015 International Society of Neuropathology.

Tick-Borne Viruses and Biological Processes at the Tick-Host-Virus Interface

PubMed Central

Kazimírová, Mária; Thangamani, Saravanan; Bartíková, Pavlína; Hermance, Meghan; Holíková, Viera; Štibrániová, Iveta; Nuttall, Patricia A.

2017-01-01

Ticks are efficient vectors of arboviruses, although less than 10% of tick species are known to be virus vectors. Most tick-borne viruses (TBV) are RNA viruses some of which cause serious diseases in humans and animals world-wide. Several TBV impacting human or domesticated animal health have been found to emerge or re-emerge recently. In order to survive in nature, TBV must infect and replicate in both vertebrate and tick cells, representing very different physiological environments. Information on molecular mechanisms that allow TBV to switch between infecting and replicating in tick and vertebrate cells is scarce. In general, ticks succeed in completing their blood meal thanks to a plethora of biologically active molecules in their saliva that counteract and modulate different arms of the host defense responses (haemostasis, inflammation, innate and acquired immunity, and wound healing). The transmission of TBV occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. However, the underlying molecular mechanisms of TBV transmission are poorly understood. Immunomodulatory properties of tick saliva helping overcome the first line of defense to injury and early interactions at the tick-host skin interface appear to be essential in successful TBV transmission and infection of susceptible vertebrate hosts. The local host skin site of tick attachment, modulated by tick saliva, is an important focus of virus replication. Immunomodulation of the tick attachment site also promotes co-feeding transmission of viruses from infected to non-infected ticks in the absence of host viraemia (non-viraemic transmission). Future research should be aimed at identification of the key tick salivary molecules promoting virus transmission, and a molecular description of tick-host-virus interactions and of tick-mediated skin immunomodulation. Such insights will enable the rationale design of anti-tick vaccines that protect against disease caused by tick-borne viruses. PMID:28798904

Tick-Borne Viruses and Biological Processes at the Tick-Host-Virus Interface.

PubMed

Kazimírová, Mária; Thangamani, Saravanan; Bartíková, Pavlína; Hermance, Meghan; Holíková, Viera; Štibrániová, Iveta; Nuttall, Patricia A

2017-01-01

Ticks are efficient vectors of arboviruses, although less than 10% of tick species are known to be virus vectors. Most tick-borne viruses (TBV) are RNA viruses some of which cause serious diseases in humans and animals world-wide. Several TBV impacting human or domesticated animal health have been found to emerge or re-emerge recently. In order to survive in nature, TBV must infect and replicate in both vertebrate and tick cells, representing very different physiological environments. Information on molecular mechanisms that allow TBV to switch between infecting and replicating in tick and vertebrate cells is scarce. In general, ticks succeed in completing their blood meal thanks to a plethora of biologically active molecules in their saliva that counteract and modulate different arms of the host defense responses (haemostasis, inflammation, innate and acquired immunity, and wound healing). The transmission of TBV occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. However, the underlying molecular mechanisms of TBV transmission are poorly understood. Immunomodulatory properties of tick saliva helping overcome the first line of defense to injury and early interactions at the tick-host skin interface appear to be essential in successful TBV transmission and infection of susceptible vertebrate hosts. The local host skin site of tick attachment, modulated by tick saliva, is an important focus of virus replication. Immunomodulation of the tick attachment site also promotes co-feeding transmission of viruses from infected to non-infected ticks in the absence of host viraemia (non-viraemic transmission). Future research should be aimed at identification of the key tick salivary molecules promoting virus transmission, and a molecular description of tick-host-virus interactions and of tick-mediated skin immunomodulation. Such insights will enable the rationale design of anti-tick vaccines that protect against disease caused by tick-borne viruses.

Contrasting hydraulic strategies in two tropical lianas and their host trees.

PubMed

Johnson, Daniel M; Domec, Jean-Christophe; Woodruff, David R; McCulloh, Katherine A; Meinzer, Frederick C

2013-02-01

Tropical liana abundance has been increasing over the past 40 yr, which has been associated with reduced rainfall. The proposed mechanism allowing lianas to thrive in dry conditions is deeper root systems than co-occurring trees, although we know very little about the fundamental hydraulic physiology of lianas. To test the hypothesis that two abundant liana species would physiologically outperform their host tree under reduced water availability, we measured rooting depth, hydraulic properties, plant water status, and leaf gas exchange during the dry season in a seasonally dry tropical forest. We also used a model to compare water use by one of the liana species and the host tree during drought. All species measured were shallowly rooted. The liana species were more vulnerable to embolism than host trees and experienced water potentials that were predicted to result in substantial hydraulic losses in both leaves and stems. Water potentials measured in host trees were not negative enough to result in significant hydraulic losses. Model results predicted the liana to have greater gas exchange than its host tree during drought and nondrought conditions. The host tree species had a more conservative strategy for maintenance of the soil-to-leaf hydraulic pathway than the lianas it supported. The two liana species experienced embolism in stems and leaves, based on vulnerability curves and water potentials. These emboli were presumably repaired before the next morning. However, in the host tree species, reduced stomatal conductance prevented leaf or stem embolism.

Parasitization by Cotesia chilonis influences gene expression in fatbody and hemocytes of Chilo suppressalis

USDA-ARS?s Scientific Manuscript database

During oviposition many parasitoid wasps inject various factors along with eggs that manipulate the physiology and development of their hosts. These manipulations are thought to benefit the parasites. However, the detailed mechanisms of host-parasitoid interactions are not fully understood. We posed...

Costs and benefits of sublethal Drosophila C virus infection.

PubMed

Gupta, V; Stewart, C O; Rund, S S C; Monteith, K; Vale, P F

2017-07-01

Viruses are major evolutionary drivers of insect immune systems. Much of our knowledge of insect immune responses derives from experimental infections using the fruit fly Drosophila melanogaster. Most experiments, however, employ lethal pathogen doses through septic injury, frequently overwhelming host physiology. While this approach has revealed several immune mechanisms, it is less informative about the fitness costs hosts may experience during infection in the wild. Using both systemic and oral infection routes, we find that even apparently benign, sublethal infections with the horizontally transmitted Drosophila C virus (DCV) can cause significant physiological and behavioural morbidity that is relevant for host fitness. We describe DCV-induced effects on fly reproductive output, digestive health and locomotor activity, and we find that viral morbidity varies according to the concentration of pathogen inoculum, host genetic background and sex. Notably, sublethal DCV infection resulted in a significant increase in fly reproduction, but this effect depended on host genotype. We discuss the relevance of sublethal morbidity for Drosophila ecology and evolution, and more broadly, we remark on the implications of deleterious and beneficial infections for the evolution of insect immunity. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Development of the preterm infant gut microbiome: A research priority

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groer, Maureen W.; Luciano, Angel A.; Dishaw, Larry J.

The very low birth weight (VLBW) infant is at great risk for marked dysbiosis of the gut microbiome due to multiple factors, including physiological immaturity and prenatal/postnatal influences that disrupt the development of a normal gut flora. However, little is known about the developmental succession of the microbiota in preterm infants as they grow and mature. This review provides a synthesis of our understanding of the normal development of the infant gut microbiome and contrasts this with dysbiotic development in the VLBW infant. The role of human milk in normal gut microbial development is emphasized, along with the role ofmore » the gut microbiome in immune development and gastroenteric health. Current research provides evidence that the gut microbiome interacts extensively with many physiological systems and metabolic processes in the developing infant. However, to the best of our knowledge, there are currently no studies prospectively mapping the gut microbiome of VLBW infants through early childhood. This knowledge gap must be filled to inform a healthcare system that can provide for the growth, health, and development of VLBW infants. In conclusion, the study speculates about how the VLBW infants’ gut microbiome might function through host-microbe interactions to contribute to the sequelae of preterm birth, including its influence on growth, development, and general health of the infant host.« less

Development of the preterm infant gut microbiome: A research priority

DOE PAGES

Groer, Maureen W.; Luciano, Angel A.; Dishaw, Larry J.; ...

2014-10-13

The very low birth weight (VLBW) infant is at great risk for marked dysbiosis of the gut microbiome due to multiple factors, including physiological immaturity and prenatal/postnatal influences that disrupt the development of a normal gut flora. However, little is known about the developmental succession of the microbiota in preterm infants as they grow and mature. This review provides a synthesis of our understanding of the normal development of the infant gut microbiome and contrasts this with dysbiotic development in the VLBW infant. The role of human milk in normal gut microbial development is emphasized, along with the role ofmore » the gut microbiome in immune development and gastroenteric health. Current research provides evidence that the gut microbiome interacts extensively with many physiological systems and metabolic processes in the developing infant. However, to the best of our knowledge, there are currently no studies prospectively mapping the gut microbiome of VLBW infants through early childhood. This knowledge gap must be filled to inform a healthcare system that can provide for the growth, health, and development of VLBW infants. In conclusion, the study speculates about how the VLBW infants’ gut microbiome might function through host-microbe interactions to contribute to the sequelae of preterm birth, including its influence on growth, development, and general health of the infant host.« less

New records with examples of potential host colonization events for hypopi (Acari: Hypoderatidae) from birds

USGS Publications Warehouse

Pence, Danny B.; Spalding, M.G.; Bergan, J.F.; Cole, Rebecca A.

1997-01-01

New host, geographic records, or both are established for 14 species of hypoderatid deutonymphs from 14 species of birds in North America. Ten of these records are regarded as examples of a potential host colonization event where these hypopi have become established in hosts other than those with which they are normally associated. Herein, potential host colonization events by hypoderatid deutonymphs are regarded as more of an ecologically determined than physiologically specific phenomenon, often specifically related to sharing of nesting sites in the same rookeries by different host taxa. Neottialges ibisicola Young & Pence is placed as a junior synonym of Neottialges plegadicola Fain. The taxonomic status of Hypodectes propus from columbid versus ardeid hosts needs further study.

Wound healing.

PubMed

Harvey, Carol

2005-01-01

Wound healing in orthopaedic care is affected by the causes of the wound, as well as concomitant therapies used to repair musculoskeletal structures. Promoting the health of the host and creating an environment to foster natural healing processes is essential for helping to restore skin integrity. Normal wound healing physiologic processes, factors affecting wound healing, wound classification systems, unique characteristics of orthopaedic wounds, wound contamination and drainage characteristics, and potential complications are important to understand in anticipation of patient needs. Accurate wound assessment and knowledge of nursing implications with specific wound care measures (cleansing, debridement, and dressings) is important for quality care. New technologies are enhancing traditional wound care measures with goals of effective comfortable wound care to promote restoration of skin integrity.

Optimizing eukaryotic cell hosts for protein production through systems biotechnology and genome-scale modeling.

PubMed

Gutierrez, Jahir M; Lewis, Nathan E

2015-07-01

Eukaryotic cell lines, including Chinese hamster ovary cells, yeast, and insect cells, are invaluable hosts for the production of many recombinant proteins. With the advent of genomic resources, one can now leverage genome-scale computational modeling of cellular pathways to rationally engineer eukaryotic host cells. Genome-scale models of metabolism include all known biochemical reactions occurring in a specific cell. By describing these mathematically and using tools such as flux balance analysis, the models can simulate cell physiology and provide targets for cell engineering that could lead to enhanced cell viability, titer, and productivity. Here we review examples in which metabolic models in eukaryotic cell cultures have been used to rationally select targets for genetic modification, improve cellular metabolic capabilities, design media supplementation, and interpret high-throughput omics data. As more comprehensive models of metabolism and other cellular processes are developed for eukaryotic cell culture, these will enable further exciting developments in cell line engineering, thus accelerating recombinant protein production and biotechnology in the years to come. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Neuro-immune interactions in inflammation and host defense: Implications for transplantation.

PubMed

Chavan, Sangeeta S; Ma, Pingchuan; Chiu, Isaac M

2018-03-01

Sensory and autonomic neurons of the peripheral nervous system (PNS) play a critical role in regulating the immune system during tissue inflammation and host defense. Recent studies have identified the molecular mechanisms underlying the bidirectional communication between the nervous system and the immune system. Here, we highlight the studies that demonstrate the importance of the neuro-immune interactions in health and disease. Nociceptor sensory neurons detect immune mediators to produce pain, and release neuropeptides that act on the immune system to regulate inflammation. In parallel, neural reflex circuits including the vagus nerve-based inflammatory reflex are physiological regulators of inflammatory responses and cytokine production. In transplantation, neuro-immune communication could significantly impact the processes of host-pathogen defense, organ rejection, and wound healing. Emerging approaches to target the PNS such as bioelectronics could be useful in improving the outcome of transplantation. Therefore, understanding how the nervous system shapes the immune response could have important therapeutic ramifications for transplantation medicine. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

Thermal Stress Triggers Broad Pocillopora damicornis Transcriptomic Remodeling, while Vibrio coralliilyticus Infection Induces a More Targeted Immuno-Suppression Response

PubMed Central

Vidal-Dupiol, Jeremie; Dheilly, Nolwenn M.; Rondon, Rodolfo; Grunau, Christoph; Cosseau, Céline; Smith, Kristina M.; Freitag, Michael; Adjeroud, Mehdi; Mitta, Guillaume

2014-01-01

Global change and its associated temperature increase has directly or indirectly changed the distributions of hosts and pathogens, and has affected host immunity, pathogen virulence and growth rates. This has resulted in increased disease in natural plant and animal populations worldwide, including scleractinian corals. While the effects of temperature increase on immunity and pathogen virulence have been clearly identified, their interaction, synergy and relative weight during pathogenesis remain poorly documented. We investigated these phenomena in the interaction between the coral Pocillopora damicornis and the bacterium Vibrio coralliilyticus, for which the infection process is temperature-dependent. We developed an experimental model that enabled unraveling the effects of thermal stress, and virulence vs. non-virulence of the bacterium. The physiological impacts of various treatments were quantified at the transcriptome level using a combination of RNA sequencing and targeted approaches. The results showed that thermal stress triggered a general weakening of the coral, making it more prone to infection, non-virulent bacterium induced an ‘efficient’ immune response, whereas virulent bacterium caused immuno-suppression in its host. PMID:25259845

A method to quantify infection and colonization of holm oak (Quercus ilex) roots by Phytophthora cinnamomi

PubMed Central

2012-01-01

Phytophthora cinnamomi Rands. is an important root rot pathogen widely distributed in the north hemisphere, with a large host range. Among others diseases, it is known to be a principal factor in the decline of holm oak and cork oak, the most important tree species in the “dehesa” ecosystem of south-western Spain. Previously, the focus of studies on P. cinnamomi and holm oak have been on molecular tools for identification, functional responses of the host, together with other physiological and morphological host variables. However, a microscopic index to describe the degree of infection and colonization in the plant tissues has not yet been developed. A colonization or infection index would be a useful tool for studies that examine differences between individuals subjected to different treatments or to individuals belonging to different breeding accessions, together with their specific responses to the pathogen. This work presents a methodology based on the capture and digital treatment of microscopic images, using simple and accessible software, together with a range of variables that quantify the infection and colonization process. PMID:22974221

The role of Candida albicans AP-1 protein against host derived ROS in in vivo models of infection.

PubMed

Jain, Charu; Pastor, Kelly; Gonzalez, Arely Y; Lorenz, Michael C; Rao, Reeta P

2013-01-01

Candida albicans is a major fungal pathogen of humans, causing mucosal infections that are difficult to eliminate and systemic infections that are often lethal primarily due to defects in the host's innate status. Here we demonstrate the utility of Caenorhabditis elegans, a model host to study innate immunity, by exploring the role of reactive oxygen species (ROS) as a critical innate response against C. albicans infections. Much like a human host, the nematode's innate immune response is activated to produce ROS in response to fungal infection. We use the C. albicans cap1 mutant, which is susceptible to ROS, as a tool to dissect this physiological innate immune response and show that cap1 mutants fail to cause disease and death, except in bli-3 mutant worms that are unable to produce ROS because of a defective NADPH oxidase. We further validate the ROS-mediated host defense mechanism in mammalian phagocytes by demonstrating that chemical inhibition of the NADPH oxidase in cultured macrophages enables the otherwise susceptible cap1 mutant to resists ROS-mediated phagolysis. Loss of CAP1 confers minimal attenuation of virulence in a disseminated mouse model, suggesting that CAP1-independent mechanisms contribute to pathogen survival in vivo. Our findings underscore a central theme in the process of infection-the intricate balance between the virulence strategies employed by C. albicans and the host's innate immune system and validates C. elegans as a simple model host to dissect this balance at the molecular level.

Bacterial growth, flow, and mixing shape human gut microbiota density and composition.

PubMed

Arnoldini, Markus; Cremer, Jonas; Hwa, Terence

2018-03-13

The human gut microbiota is highly dynamic, and host physiology and diet exert major influences on its composition. In our recent study, we integrated new quantitative measurements on bacterial growth physiology with a reanalysis of published data on human physiology to build a comprehensive modeling framework. This can generate predictions of how changes in different host factors influence microbiota composition. For instance, hydrodynamic forces in the colon, along with colonic water absorption that manifests as transit time, exert a major impact on microbiota density and composition. This can be mechanistically explained by their effect on colonic pH which directly affects microbiota competition for food. In this addendum, we describe the underlying analysis in more detail. In particular, we discuss the mixing dynamics of luminal content by wall contractions and its implications for bacterial growth and density, as well as the broader implications of our insights for the field of gut microbiota research.

Free-living pathogens: life-history constraints and strain competition

PubMed Central

Caraco, Thomas; Wang, Ing-Nang

2008-01-01

Many pathogen life histories include a free-living stage, often with anatomical and physiological adaptations promoting persistence outside of host tissues. More durable particles presumably require that the pathogen metabolize more resources per particle. Therefore, we hypothesize functional dependencies, pleiotropic constraints, between the rate at which free-living particles decay outside of host tissues and other pathogen traits, including virulence, the probability of infecting a host upon contact, and pathogen reproduction within host tissues. Assuming that pathogen strains compete for hosts preemptively, we find patterns in trait dependencies predicting whether or not strain competition favors a highly persistent free-living stage. PMID:18062992

Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree ring C and O stable isotopes

EPA Science Inventory

• Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually induce tree death. • To investigate long-term impacts of dwarf mistletoe...

Phage phenomics: Physiological approaches to characterize novel viral proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez, Savannah E.; Cuevas, Daniel A.; Rostron, Jason E.

Current investigations into phage-host interactions are dependent on extrapolating knowledge from (meta)genomes. Interestingly, 60 - 95% of all phage sequences share no homology to current annotated proteins. As a result, a large proportion of phage genes are annotated as hypothetical. This reality heavily affects the annotation of both structural and auxiliary metabolic genes. Here we present phenomic methods designed to capture the physiological response(s) of a selected host during expression of one of these unknown phage genes. Multi-phenotype Assay Plates (MAPs) are used to monitor the diversity of host substrate utilization and subsequent biomass formation, while metabolomics provides bi-product analysismore » by monitoring metabolite abundance and diversity. Both tools are used simultaneously to provide a phenotypic profile associated with expression of a single putative phage open reading frame (ORF). Thus, representative results for both methods are compared, highlighting the phenotypic profile differences of a host carrying either putative structural or metabolic phage genes. In addition, the visualization techniques and high throughput computational pipelines that facilitated experimental analysis are presented.« less

Phage phenomics: Physiological approaches to characterize novel viral proteins

DOE PAGES

Sanchez, Savannah E.; Cuevas, Daniel A.; Rostron, Jason E.; ...

2015-06-11

Current investigations into phage-host interactions are dependent on extrapolating knowledge from (meta)genomes. Interestingly, 60 - 95% of all phage sequences share no homology to current annotated proteins. As a result, a large proportion of phage genes are annotated as hypothetical. This reality heavily affects the annotation of both structural and auxiliary metabolic genes. Here we present phenomic methods designed to capture the physiological response(s) of a selected host during expression of one of these unknown phage genes. Multi-phenotype Assay Plates (MAPs) are used to monitor the diversity of host substrate utilization and subsequent biomass formation, while metabolomics provides bi-product analysismore » by monitoring metabolite abundance and diversity. Both tools are used simultaneously to provide a phenotypic profile associated with expression of a single putative phage open reading frame (ORF). Thus, representative results for both methods are compared, highlighting the phenotypic profile differences of a host carrying either putative structural or metabolic phage genes. In addition, the visualization techniques and high throughput computational pipelines that facilitated experimental analysis are presented.« less

Inorganic elements in the fat bodies of Diatraea saccharalis (Lepidoptera: Crambidae) larvae parasitized by Cotesia flavipes (Hymenoptera: Braconidae).

PubMed

Pinheiro, D O; Zucchi, T D; Zucchi, O L A D; Nascimento Filho, V F; Almeida, E; Cônsoli, F L

2010-08-01

Koinobiont parasitoids use several strategies to regulate the host's physiological processes during parasitism. Although many aspects of host-parasitoid interactions have been explored, studies that attempted to assess the effects of parasitism on the availability of inorganic elements in the host are virtually nonexistent. Therefore, we aimed to evaluate the effects of parasitism on the concentrations of inorganic elements in the fat bodies of larvae of Diatraea saccharalis (Lepidoptera: Crambidae) during the development of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae), by using total reflection X-ray fluorescence (TXRF). TXRF analysis allowed comparisons of the changes in the availability of the elements P, S, K, Ca, Cr, Fe, Ni, Cu, and Zn in the fat body tissues of D. saccharalis larvae parasitized by C. flavipes. Overall, the concentration of inorganic elements was higher early in parasitoid development (1 and 3days after parasitism) compared to non-parasitized larvae, but much lower towards the end of parasitoid development (7 and 9days after parasitism). Ca, K, and S were reduced after the fifth day of parasitism, which affected the total abundance of inorganic elements observed in the fat bodies of the parasitized hosts. The regulatory mechanisms or pathological effects related to the observed variation of the host inorganic elements induced by the parasitoid remain unknown, but there might be a strategy to make these elements available to the parasitoid larvae at the end of their development, when higher metabolic activity of the host fat body is required to sustain parasitoid growth. The observed variation of the host's inorganic elements could also be related to the known effects of parasitism on the host's immune response. 2010 Elsevier Inc. All rights reserved.

Deep sequencing-based transcriptome analysis of Plutella xylostella larvae parasitized by Diadegma semiclausum

PubMed Central

2011-01-01

Background Parasitoid insects manipulate their hosts' physiology by injecting various factors into their host upon parasitization. Transcriptomic approaches provide a powerful approach to study insect host-parasitoid interactions at the molecular level. In order to investigate the effects of parasitization by an ichneumonid wasp (Diadegma semiclausum) on the host (Plutella xylostella), the larval transcriptome profile was analyzed using a short-read deep sequencing method (Illumina). Symbiotic polydnaviruses (PDVs) associated with ichneumonid parasitoids, known as ichnoviruses, play significant roles in host immune suppression and developmental regulation. In the current study, D. semiclausum ichnovirus (DsIV) genes expressed in P. xylostella were identified and their sequences compared with other reported PDVs. Five of these genes encode proteins of unknown identity, that have not previously been reported. Results De novo assembly of cDNA sequence data generated 172,660 contigs between 100 and 10000 bp in length; with 35% of > 200 bp in length. Parasitization had significant impacts on expression levels of 928 identified insect host transcripts. Gene ontology data illustrated that the majority of the differentially expressed genes are involved in binding, catalytic activity, and metabolic and cellular processes. In addition, the results show that transcription levels of antimicrobial peptides, such as gloverin, cecropin E and lysozyme, were up-regulated after parasitism. Expression of ichnovirus genes were detected in parasitized larvae with 19 unique sequences identified from five PDV gene families including vankyrin, viral innexin, repeat elements, a cysteine-rich motif, and polar residue rich protein. Vankyrin 1 and repeat element 1 genes showed the highest transcription levels among the DsIV genes. Conclusion This study provides detailed information on differential expression of P. xylostella larval genes following parasitization, DsIV genes expressed in the host and also improves our current understanding of this host-parasitoid interaction. PMID:21906285

Microsporidia and 'the art of living together'.

PubMed

Vávra, Jiří; Lukeš, Julius

2013-01-01

Parasitism, aptly defined as one of the 'living-together' strategies (Trager, 1986), presents a dynamic system in which the parasite and its host are under evolutionary pressure to evolve new and specific adaptations, thus enabling the coexistence of the two closely interacting partners. Microsporidia are very frequently encountered obligatory intracellular protistan parasites that can infect both animals and some protists and are a consummate example of various aspects of the 'living-together' strategy. Microsporidia, relatives of fungi in the superkingdom Opisthokonta, belong to the relatively small group of parasites for which the host cell cytoplasm is the site of both reproduction and maturation. The structural and physiological reduction of their vegetative stage, together with the manipulation of host cell physiology, enables microsporidia to live in the cytosolic environment for most of their life cycle in a way resembling endocytobionts. The ability to form structurally complex spores and the invention and assembly of a unique injection mechanism enable microsporidia to disperse within host tissues and between host organisms, resulting in long-lasting infections. Microsporidia have adapted their genomes to the intracellular way of life, evolved strategies how to obtain nutrients directly from the host and how to manipulate not only the infected cells, but also the hosts themselves. The enormous variability of host organisms and their tissues provide microsporidian parasites a virtually limitless terrain for diversification and ecological expansion. This review attempts to present a general overview of microsporidia, emphasising some less known and/or more recently discovered facets of their biology. Copyright © 2013 Elsevier Ltd. All rights reserved.

Human host defense peptides - role in maintaining human homeostasis and pathological processes.

PubMed

Dawgul, Malgorzata Anna; Greber, Katarzyna Ewa; Sawicki, Wieslaw; Kamysz, Wojciech

2016-12-12

The human body expresses over 100 host defense peptides and proteins (antimicrobial peptides, AMPs). The compounds are produced by tissues and mucosal surfaces, e.g. skin, the digestive and urinary tract, the ocular surface and neutrophils, and are believed to play a crucial role in defense from microbial infection. They are considered to protect the human body against microbial infections due to their antimicrobial and immunomodulatory activities. As well as having strong antimicrobial activity towards a broad spectrum of microorganisms, AMPs have been found to interact with neutrophils, monocytes and T-cells and promote the production of cytokines. They also neutralize the action of lipopolysaccharide (LPS) and play a crucial role in wound healing processes. In response to the microbial stimuli the AMPs are released in order to fight the infection, however there are several microorganisms evading the human immune system by downregulation of AMPs. Decreased or elevated expression of AMPs is associated also with several non-infectious diseases. Despite numerous studies conducted in the field of AMPs over the last few decades, their exact role in physiological and pathological processes remains to be explained. In this paper, we review the most significant human AMPs and their potential roles in maintaining human homeostasis as well as in pathological processes.

Intervention strategies for cesarean section–induced alterations in the microbiota-gut-brain axis

PubMed Central

Moya-Pérez, Angela; Luczynski, Pauline; Renes, Ingrid B.; Wang, Shugui; Borre, Yuliya; Anthony Ryan, C.; Knol, Jan; Stanton, Catherine; Dinan, Timothy G.

2017-01-01

Microbial colonization of the gastrointestinal tract is an essential process that modulates host physiology and immunity. Recently, researchers have begun to understand how and when these microorganisms colonize the gut and the early-life factors that impact their natural ecological establishment. The vertical transmission of maternal microbes to the offspring is a critical factor for host immune and metabolic development. Increasing evidence also points to a role in the wiring of the gut-brain axis. This process may be altered by various factors such as mode of delivery, gestational age at birth, the use of antibiotics in early life, infant feeding, and hygiene practices. In fact, these early exposures that impact the intestinal microbiota have been associated with the development of diseases such as obesity, type 1 diabetes, asthma, allergies, and even neurodevelopmental disorders. The present review summarizes the impact of cesarean birth on the gut microbiome and the health status of the developing infant and discusses possible preventative and restorative strategies to compensate for early-life microbial perturbations. PMID:28379454

Lysophosphatidylcholine Regulates Sexual Stage Differentiation in the Human Malaria Parasite Plasmodium falciparum.

PubMed

Brancucci, Nicolas M B; Gerdt, Joseph P; Wang, ChengQi; De Niz, Mariana; Philip, Nisha; Adapa, Swamy R; Zhang, Min; Hitz, Eva; Niederwieser, Igor; Boltryk, Sylwia D; Laffitte, Marie-Claude; Clark, Martha A; Grüring, Christof; Ravel, Deepali; Blancke Soares, Alexandra; Demas, Allison; Bopp, Selina; Rubio-Ruiz, Belén; Conejo-Garcia, Ana; Wirth, Dyann F; Gendaszewska-Darmach, Edyta; Duraisingh, Manoj T; Adams, John H; Voss, Till S; Waters, Andrew P; Jiang, Rays H Y; Clardy, Jon; Marti, Matthias

2017-12-14

Transmission represents a population bottleneck in the Plasmodium life cycle and a key intervention target of ongoing efforts to eradicate malaria. Sexual differentiation is essential for this process, as only sexual parasites, called gametocytes, are infective to the mosquito vector. Gametocyte production rates vary depending on environmental conditions, but external stimuli remain obscure. Here, we show that the host-derived lipid lysophosphatidylcholine (LysoPC) controls P. falciparum cell fate by repressing parasite sexual differentiation. We demonstrate that exogenous LysoPC drives biosynthesis of the essential membrane component phosphatidylcholine. LysoPC restriction induces a compensatory response, linking parasite metabolism to the activation of sexual-stage-specific transcription and gametocyte formation. Our results reveal that malaria parasites can sense and process host-derived physiological signals to regulate differentiation. These data close a critical knowledge gap in parasite biology and introduce a major component of the sexual differentiation pathway in Plasmodium that may provide new approaches for blocking malaria transmission. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Microbial ecology and host-microbiota interactions during early life stages

PubMed Central

Collado, Maria Carmen; Cernada, Maria; Baüerl, Christine; Vento, Máximo; Pérez-Martínez, Gaspar

2012-01-01

The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life. PMID:22743759

Fungal phytotoxins with potential herbicidal activity: chemical and biological characterization.

PubMed

Cimmino, Alessio; Masi, Marco; Evidente, Marco; Superchi, Stefano; Evidente, Antonio

2015-12-19

Covering: 2007 to 2015 Fungal phytotoxins are secondary metabolites playing an important role in the induction of disease symptoms interfering with host plant physiological processes. Although fungal pathogens represent a heavy constraint for agrarian production and for forest and environmental heritage, they can also represent an ecofriendly alternative to manage weeds. Indeed, the phytotoxins produced by weed pathogenic fungi are an efficient tool to design natural, safe bioherbicides. Their use could avoid that of synthetic pesticides causing resistance in the host plants and the long term impact of residues in agricultural products with a risk to human and animal health. The isolation and structural and biological characterization of phytotoxins produced by pathogenic fungi for weeds, including parasitic plants, are described. Structure activity relationships and mode of action studies for some phytotoxins are also reported to elucidate the herbicide potential of these promising fungal metabolites.

The Sponge Hologenome

PubMed Central

Thomas, Torsten

2016-01-01

ABSTRACT A paradigm shift has recently transformed the field of biological science; molecular advances have revealed how fundamentally important microorganisms are to many aspects of a host’s phenotype and evolution. In the process, an era of “holobiont” research has emerged to investigate the intricate network of interactions between a host and its symbiotic microbial consortia. Marine sponges are early-diverging metazoa known for hosting dense, specific, and often highly diverse microbial communities. Here we synthesize current thoughts about the environmental and evolutionary forces that influence the diversity, specificity, and distribution of microbial symbionts within the sponge holobiont, explore the physiological pathways that contribute to holobiont function, and describe the molecular mechanisms that underpin the establishment and maintenance of these symbiotic partnerships. The collective genomes of the sponge holobiont form the sponge hologenome, and we highlight how the forces that define a sponge’s phenotype in fact act on the genomic interplay between the different components of the holobiont. PMID:27103626

Plant immunity: a lesson from pathogenic bacterial effector proteins.

PubMed

Cui, Haitao; Xiang, Tingting; Zhou, Jian-Min

2009-10-01

Phytopathogenic bacteria inject an array of effector proteins into host cells to alter host physiology and assist the infection process. Some of these effectors can also trigger disease resistance as a result of recognition in the plant cell by cytoplasmic immune receptors. In addition to effector-triggered immunity, plants immunity can be triggered upon the detection of Pathogen/Microbe-Associated Molecular Patterns by surface-localized immune receptors. Recent progress indicates that many bacterial effector proteins use a variety of biochemical properties to directly attack key components of PAMP-triggered immunity and effector-triggered immunity, providing new insights into the molecular basis of plant innate immunity. Emerging evidence indicate that the evolution of disease resistance in plants is intimately linked to the mechanism by which bacterial effectors promote parasitism. This review focuses on how these studies have conceptually advanced our understanding of plant-pathogen interactions.

Diet and the intestinal microbiome: associations, functions, and implications for health and disease.

PubMed

Albenberg, Lindsey G; Wu, Gary D

2014-05-01

The mutual relationship between the intestinal microbiota and its mammalian host is influenced by diet. Consumption of various nutrients affects the structure of the microbial community and provides substrates for microbial metabolism. The microbiota can produce small molecules that are absorbed by the host and affect many important physiological processes. Age-dependent and societal differences in the intestinal microbiota could result from differences in diet. Examples include differences in the intestinal microbiota of breastfed vs formula-fed infants or differences in microbial richness in people who consume an agrarian plant-based vs a Western diet, which is high in meat and fat. We review how diet affects the structure and metabolome of the human intestinal microbiome and may contribute to health or the pathogenesis of disorders such as coronary vascular disease and inflammatory bowel disease. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Energy conserving thermoregulatory patterns and lower disease severity in a bat resistant to the impacts of white-nose syndrome.

PubMed

Moore, Marianne S; Field, Kenneth A; Behr, Melissa J; Turner, Gregory G; Furze, Morgan E; Stern, Daniel W F; Allegra, Paul R; Bouboulis, Sarah A; Musante, Chelsey D; Vodzak, Megan E; Biron, Matthew E; Meierhofer, Melissa B; Frick, Winifred F; Foster, Jeffrey T; Howell, Daryl; Kath, Joseph A; Kurta, Allen; Nordquist, Gerda; Johnson, Joseph S; Lilley, Thomas M; Barrett, Benjamin W; Reeder, DeeAnn M

2018-01-01

The devastating bat fungal disease, white-nose syndrome (WNS), does not appear to affect all species equally. To experimentally determine susceptibility differences between species, we exposed hibernating naïve little brown myotis (Myotis lucifugus) and big brown bats (Eptesicus fuscus) to the fungus that causes WNS, Pseudogymnoascus destructans (Pd). After hibernating under identical conditions, Pd lesions were significantly more prevalent and more severe in little brown myotis. This species difference in pathology correlates with susceptibility to WNS in the wild and suggests that survival is related to different host physiological responses. We observed another fungal infection, associated with neutrophilic inflammation, that was equally present in all bats. This suggests that both species are capable of generating a response to cold tolerant fungi and that Pd may have evolved mechanisms for evading host responses that are effective in at least some bat species. These host-pathogen interactions are likely mediated not just by host physiological responses, but also by host behavior. Pd-exposed big brown bats, the less affected species, spent more time in torpor than did control animals, while little brown myotis did not exhibit this change. This differential thermoregulatory response to Pd infection by big brown bat hosts may allow for a more effective (or less pathological) immune response to tissue invasion.

Streptococcus pyogenes Sortase Mutants Are Highly Susceptible to Killing by Host Factors Due to Aberrant Envelope Physiology

PubMed Central

Raz, Assaf; Tanasescu, Ana-Maria; Zhao, Anna M.; Serrano, Anna; Alston, Tricia; Sol, Asaf; Bachrach, Gilad; Fischetti, Vincent A.

2015-01-01

Cell wall anchored virulence factors are critical for infection and colonization of the host by Gram-positive bacteria. Such proteins have an N-terminal leader sequence and a C-terminal sorting signal, composed of an LPXTG motif, a hydrophobic stretch, and a few positively charged amino acids. The sorting signal halts translocation across the membrane, allowing sortase to cleave the LPXTG motif, leading to surface anchoring. Deletion of sortase prevents the anchoring of virulence factors to the wall; the effects on bacterial physiology however, have not been thoroughly characterized. Here we show that deletion of Streptococcus pyogenes sortase A leads to accumulation of sorting intermediates, particularly at the septum, altering cellular morphology and physiology, and compromising membrane integrity. Such cells are highly sensitive to cathelicidin, and are rapidly killed in blood and plasma. These phenomena are not a loss-of-function effect caused by the absence of anchored surface proteins, but specifically result from the accumulation of sorting intermediates. Reduction in the level of sorting intermediates leads to a return of the sortase mutant to normal morphology, while expression of M protein with an altered LPXTG motif in wild type cells leads to toxicity in the host environment, similar to that observed in the sortase mutant. These unanticipated effects suggest that inhibition of sortase by small-molecule inhibitors could similarly lead to the rapid elimination of pathogens from an infected host, making such inhibitors much better anti-bacterial agents than previously believed. PMID:26484774

Salivary gland degeneration and vitellogenesis in the ixodid tick Amblyomma hebraeum: Surpassing a critical weight is the prerequisite and detachment from the host is the trigger.

PubMed

Friesen, Kevin J; Kaufman, W Reuben

2009-10-01

The normal engorged body weight of female ixodid ticks (Acari: Ixodidae) is about 100x the unfed weight. Virgin female Amblyomma hebraeum normally do not feed beyond 10x the unfed weight. However, about 10-20% of a population of virgins will feed to perhaps 20x the unfed weight, but not much beyond that. In A. hebraeum, when females surpass about 10x the unfed weight, the following changes in physiology occur if they are removed from the host: (a) they will not reattach if given the opportunity, (b) their salivary glands (SGs) will undergo autolysis within 4 days if they are mated or 8 days if they are virgin, and (c) egg maturation and oviposition will occur in due course. Mated or virgin female ticks removed from the host below about 10x the unfed weight do not experience the latter changes (Kaufman, W.R., Lomas, L., 1996. 'Male Factors' in ticks: their role in feeding and egg development. Invertebrate Reproduction and Development 30, 191-198). In 1984 we named this transitional weight, the 'critical weight' (CW). Its absolute value is probably a species-specific characteristic (Kaufman, W.R., 2007. Gluttony and sex in female ixodid ticks: how do they compare to other blood-sucking arthropods? Journal of Insect Physiology 53, 264-273). Although mated females tend to engorge within a day of surpassing the CW, virgin females surpassing the CW can remain attached to the host for at least several weeks more. It is not known whether the physiological changes in the SGs and ovaries listed above occur in those large virgins that remain attached, although we suppose that this would be maladaptive. Instead, we hypothesize in this study that surpassing the CW is only a prerequisite for inducing these changes, and that detachment is the actual trigger. We support our hypothesis by demonstrating that large virgins, remaining attached to a host for 8 days, did not undergo SG degeneration nor complete egg maturation during the attachment period. Those changes occurred only within 8 days following detachment. So some type of sensory information associated with attachment to the host, and still undefined, inhibits expression of the physiological changes hitherto associated merely with surpassing the CW.

Microbiota-induced changes in drosophila melanogaster host gene expression and gut morphology.

PubMed

Broderick, Nichole A; Buchon, Nicolas; Lemaitre, Bruno

2014-05-27

To elucidate mechanisms underlying the complex relationships between a host and its microbiota, we used the genetically tractable model Drosophila melanogaster. Consistent with previous studies, the microbiota was simple in composition and diversity. However, analysis of single flies revealed high interfly variability that correlated with differences in feeding. To understand the effects of this simple and variable consortium, we compared the transcriptome of guts from conventionally reared flies to that for their axenically reared counterparts. Our analysis of two wild-type fly lines identified 121 up- and 31 downregulated genes. The majority of these genes were associated with immune responses, tissue homeostasis, gut physiology, and metabolism. By comparing the transcriptomes of young and old flies, we identified temporally responsive genes and showed that the overall impact of microbiota was greater in older flies. In addition, comparison of wild-type gene expression with that of an immune-deficient line revealed that 53% of upregulated genes exerted their effects through the immune deficiency (Imd) pathway. The genes included not only classic immune response genes but also those involved in signaling, gene expression, and metabolism, unveiling new and unexpected connections between immunity and other systems. Given these findings, we further characterized the effects of gut-associated microbes on gut morphology and epithelial architecture. The results showed that the microbiota affected gut morphology through their impacts on epithelial renewal rate, cellular spacing, and the composition of different cell types in the epithelium. Thus, while bacteria in the gut are highly variable, the influence of the microbiota at large has far-reaching effects on host physiology. The guts of animals are in constant association with microbes, and these interactions are understood to have important roles in animal development and physiology. Yet we know little about the mechanisms underlying the establishment and function of these associations. Here, we used the fruit fly to understand how the microbiota affects host function. Importantly, we found that the microbiota has far-reaching effects on host physiology, ranging from immunity to gut structure. Our results validate the notion that important insights on complex host-microbe relationships can be obtained from the use of a well-established and genetically tractable invertebrate model. Copyright © 2014 Broderick et al.

Functional evaluation of Heat Shock Proteins 70 (HSP70/HSC70) on Rhodnius prolixus (Hemiptera, Reduviidae) physiological responses associated with feeding and starvation.

PubMed

Paim, Rafaela M M; Araujo, Ricardo N; Leis, Miguel; Sant'anna, Mauricio R V; Gontijo, Nelder F; Lazzari, Claudio R; Pereira, Marcos H

2016-10-01

Blood-sucking vectors must overcome thermal stress caused by intake of proportionally large amounts of warm blood from their hosts. In response to this, Heat Shock Proteins (HSPs) such as the widely studied HSP70 family (the inducible HSP70 and the cognate form HSC70, known for their role in preserving essential cellular functions) are rapidly up-regulated in their tissues. The triatomine Rhodnius prolixus is an important vector of Trypanosoma cruzi, the causative pathogen of Chagas' disease, and is also a model organism for studying insect biology and physiology. In this work, we observed that the expression of Rhodnius prolixus HSP70 was rapidly up-regulated in response to thermal shocks (0 °C and 40 °C) and also during the first hours after feeding on blood. HSP70/HSC70 RNAi knockdown elicited important alterations in R. prolixus physiological responses triggered by blood meal and starvation. HSP70/HSC70 knockdown insects showed lower resistance to prolonged starvation in comparison to appropriate controls, dying between 32 and 40 days after dsRNA injection. After blood feeding, the physiological effects of HSP70/HSC70 knockdown were more prominent and the insects died even earlier, within 14-20 days after feeding (21-27 days after dsRNA injection). These bugs showed impaired blood processing and digestion, reduced energetic metabolism and the midgut immune responses were compromised. Our findings suggest that HSP70/HSC70 depletion affected R. prolixus in starvation or fed conditions. After feeding, the arrival of blood in the digestive tract of knockdown insects fails to activate essential signaling pathways involved in blood processing, producing several alterations in their physiological processes enough to generate a premature death. Copyright © 2016 Elsevier Ltd. All rights reserved.

Through Ageing, and Beyond: Gut Microbiota and Inflammatory Status in Seniors and Centenarians

PubMed Central

Biagi, Elena; Nylund, Lotta; Candela, Marco; Ostan, Rita; Bucci, Laura; Pini, Elisa; Nikkïla, Janne; Monti, Daniela; Satokari, Reetta; Franceschi, Claudio; Brigidi, Patrizia; De Vos, Willem

2010-01-01

Background Age-related physiological changes in the gastrointestinal tract, as well as modifications in lifestyle, nutritional behaviour, and functionality of the host immune system, inevitably affect the gut microbiota, resulting in a greater susceptibility to infections. Methodology/Principal Findings By using the Human Intestinal Tract Chip (HITChip) and quantitative PCR of 16S rRNA genes of Bacteria and Archaea, we explored the age-related differences in the gut microbiota composition among young adults, elderly, and centenarians, i.e subjects who reached the extreme limits of the human lifespan, living for over 100 years. We observed that the microbial composition and diversity of the gut ecosystem of young adults and seventy-years old people is highly similar but differs significantly from that of the centenarians. After 100 years of symbiotic association with the human host, the microbiota is characterized by a rearrangement in the Firmicutes population and an enrichment in facultative anaerobes, notably pathobionts. The presence of such a compromised microbiota in the centenarians is associated with an increased inflammatory status, also known as inflammageing, as determined by a range of peripheral blood inflammatory markers. This may be explained by a remodelling of the centenarians' microbiota, with a marked decrease in Faecalibacterium prauznitzii and relatives, symbiotic species with reported anti-inflammatory properties. As signature bacteria of the long life we identified specifically Eubacterium limosum and relatives that were more than ten-fold increased in the centenarians. Conclusions/Significance We provide evidence for the fact that the ageing process deeply affects the structure of the human gut microbiota, as well as its homeostasis with the host's immune system. Because of its crucial role in the host physiology and health status, age-related differences in the gut microbiota composition may be related to the progression of diseases and frailty in the elderly population. PMID:20498852

Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont, Desulfobulbus oralis.

PubMed

Cross, Karissa L; Chirania, Payal; Xiong, Weili; Beall, Clifford J; Elkins, James G; Giannone, Richard J; Griffen, Ann L; Guss, Adam M; Hettich, Robert L; Joshi, Snehal S; Mokrzan, Elaine M; Martin, Roman K; Zhulin, Igor B; Leys, Eugene J; Podar, Mircea

2018-03-13

The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously uncultured Desulfobulbus oralis , the first human-associated representative of its genus. As mammalian-associated microbes rarely have free-living close relatives, D. oralis provides opportunities to study how bacteria adapt and evolve within a host. This sulfate-reducing deltaproteobacterium has adapted to the human oral subgingival niche by curtailing its physiological repertoire, losing some biosynthetic abilities and metabolic independence, and by dramatically reducing environmental sensing and signaling capabilities. The genes that enable free-living Desulfobulbus to synthesize the potent neurotoxin methylmercury were also lost by D. oralis , a notably positive outcome of host association. However, horizontal gene acquisitions from other members of the microbiota provided novel mechanisms of interaction with the human host, including toxins like leukotoxin and hemolysins. Proteomic and transcriptomic analysis revealed that most of those factors are actively expressed, including in the subgingival environment, and some are secreted. Similar to other known oral pathobionts, D. oralis can trigger a proinflammatory response in oral epithelial cells, suggesting a direct role in the development of periodontal disease. IMPORTANCE Animal-associated microbiota likely assembled as a result of numerous independent colonization events by free-living microbes followed by coevolution with their host and other microbes. Through specific adaptation to various body sites and physiological niches, microbes have a wide range of contributions, from beneficial to disease causing. Desulfobulbus oralis provides insights into genomic and physiological transformations associated with transition from an open environment to a host-dependent lifestyle and the emergence of pathogenicity. Through a multifaceted mechanism triggering a proinflammatory response, D. oralis is a novel periodontal pathobiont. Even though culture-independent approaches can provide insights into the potential role of the human microbiome "dark matter," cultivation and experimental characterization remain important to studying the roles of individual organisms in health and disease.

Effects of sex and locality on the abundance of lice on the wild rodent Oligoryzomys nigripes.

PubMed

Fernandes, Fernanda Rodrigues; Cruz, Leonardo Dominici; Linhares, Arício Xavier

2012-10-01

Various factors can affect the parasite distribution on a host. In this study, the influence of sex, body size, and locality of a rodent host, Oligoryzomys nigripes, on lice abundance was investigated. A generalized linear model indicated that the sex and locality of O. nigripes significantly contributed to the variation in lice abundance on the host. The male bias of lice parasitizing the rodent host O. nigripes may be associated with intersexual differences in physiology and behavior, while locality differences in lice abundance may be associated with differences in host density and diversity between the two localities sampled. Studies of host-parasite associations improve the understanding of the ecology of infectious diseases, as well as the evolution of these host-parasite interactions.

Inhibition of pectin methyl esterase activity by green tea catechins.

PubMed

Lewis, Kristin C; Selzer, Tzvia; Shahar, Chen; Udi, Yael; Tworowski, Dmitry; Sagi, Irit

2008-10-01

Pectin methyl esterases (PMEs) and their endogenous inhibitors are involved in the regulation of many processes in plant physiology, ranging from tissue growth and fruit ripening to parasitic plant haustorial formation and host invasion. Thus, control of PME activity is critical for enhancing our understanding of plant physiological processes and regulation. Here, we report on the identification of epigallocatechin gallate (EGCG), a green tea component, as a natural inhibitor for pectin methyl esterases. In a gel assay for PME activity, EGCG blocked esterase activity of pure PME as well as PME extracts from citrus and from parasitic plants. Fluorometric tests were used to determine the IC50 for a synthetic substrate. Molecular docking analysis of PME and EGCG suggests close interaction of EGCG with the catalytic cleft of PME. Inhibition of PME by the green tea compound, EGCG, provides the means to study the diverse roles of PMEs in cell wall metabolism and plant development. In addition, this study introduces the use of EGCG as natural product to be used in the food industry and agriculture.

Epithelial-Mesenchymal Transition in Tissue Repair and Fibrosis

PubMed Central

Stone, Rivka C.; Pastar, Irena; Ojeh, Nkemcho; Chen, Vivien; Liu, Sophia; Garzon, Karen I.; Tomic-Canic, Marjana

2016-01-01

Epithelial-mesenchymal transition (EMT) describes the global process by which stationary epithelial cells undergo phenotypic changes, including loss of cell-cell adhesion and apical-basal polarity, and acquire mesenchymal characteristics which confer migratory capacity. EMT and its converse, MET (mesenchymal-to-epithelial transition), are integral stages of many physiologic processes, and as such are tightly coordinated by a host of molecular regulators. Converging lines of evidence have identified EMT as a component of cutaneous wound healing, during which otherwise stationary keratinocytes - the resident skin epithelial cells - migrate across the wound bed to restore the epidermal barrier. Moreover, EMT also plays a role in the development of scarring and fibrosis, as the matrix-producing myofibroblast arises from cells of epithelial lineage in response to injury but is pathologically sustained instead of undergoing MET or apoptosis. In this review, we summarize the role of EMT in physiologic repair and pathologic fibrosis of tissues and organs. We conclude that further investigation into the contribution of EMT to the impaired repair of fibrotic wounds may identify components of EMT signaling as common therapeutic targets for impaired healing in many tissues. PMID:27461257

Ethane-Bridged Bisporphyrin Conformational Changes As an Effective Analytical Tool for Nonenzymatic Detection of Urea in the Physiological Range.

PubMed

Buccolieri, Alessandro; Hasan, Mohammed; Bettini, Simona; Bonfrate, Valentina; Salvatore, Luca; Santino, Angelo; Borovkov, Victor; Giancane, Gabriele

2018-06-05

Conformational switching induced in ethane-bridged bisporphyrins was used as a sensitive transduction method for revealing the presence of urea dissolved in water via nonenzymatic approach. Bisporphyrins were deposited on solid quartz slides by means of the spin-coating method. Molecular conformations of Zn and Ni monometalated bis-porphyrins were influenced by water solvated urea molecules and their fluorescence emission was modulated by the urea concentration. Absorption, fluorescence and Raman spectroscopies allowed the identification of supramolecular processes, which are responsible for host-guest interaction between the active layers and urea molecules. A high selectivity of the sensing mechanism was highlighted upon testing the spectroscopic responses of bis-porphyrin films to citrulline and glutamine used as interfering agents. Additionally, potential applicability was demonstrated by quantifying the urea concentration in real physiological samples proposing this new approach as a valuable alternative analytical procedure to the traditionally used enzymatic methods.

Plants of the fynbos biome harbour host species-specific bacterial communities.

PubMed

Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

2016-08-01

The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An Aspartic Protease of the Scabies Mite Sarcoptes scabiei Is Involved in the Digestion of Host Skin and Blood Macromolecules

PubMed Central

Mahmood, Wajahat; Viberg, Linda T.; Fischer, Katja; Walton, Shelley F.; Holt, Deborah C.

2013-01-01

Background Scabies is a disease of worldwide significance, causing considerable morbidity in both humans and other animals. The scabies mite Sarcoptes scabiei burrows into the skin of its host, obtaining nutrition from host skin and blood. Aspartic proteases mediate a range of diverse and essential physiological functions such as tissue invasion and migration, digestion, moulting and reproduction in a number of parasitic organisms. We investigated whether aspartic proteases may play role in scabies mite digestive processes. Methodology/Principle Findings We demonstrated the presence of aspartic protease activity in whole scabies mite extract. We then identified a scabies mite aspartic protease gene sequence and produced recombinant active enzyme. The recombinant scabies mite aspartic protease was capable of digesting human haemoglobin, serum albumin, fibrinogen and fibronectin, but not collagen III or laminin. This is consistent with the location of the scabies mites in the upper epidermis of human skin. Conclusions/Significance The development of novel therapeutics for scabies is of increasing importance given the evidence of emerging resistance to current treatments. We have shown that a scabies mite aspartic protease plays a role in the digestion of host skin and serum molecules, raising the possibility that interference with the function of the enzyme may impact on mite survival. PMID:24244770

Microbial Communities and Bioactive Compounds in Marine Sponges of the Family Irciniidae—A Review

PubMed Central

Hardoim, Cristiane C. P.; Costa, Rodrigo

2014-01-01

Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species—the vast majority of which are difficult to cultivate—and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed. PMID:25272328

Potential Sabotage of Host Cell Physiology by Apicomplexan Parasites for Their Survival Benefits

PubMed Central

Chakraborty, Shalini; Roy, Sonti; Mistry, Hiral Uday; Murthy, Shweta; George, Neena; Bhandari, Vasundhra; Sharma, Paresh

2017-01-01

Plasmodium, Toxoplasma, Cryptosporidium, Babesia, and Theileria are the major apicomplexan parasites affecting humans or animals worldwide. These pathogens represent an excellent example of host manipulators who can overturn host signaling pathways for their survival. They infect different types of host cells and take charge of the host machinery to gain nutrients and prevent itself from host attack. The mechanisms by which these pathogens modulate the host signaling pathways are well studied for Plasmodium, Toxoplasma, Cryptosporidium, and Theileria, except for limited studies on Babesia. Theileria is a unique pathogen taking into account the way it modulates host cell transformation, resulting in its clonal expansion. These parasites majorly modulate similar host signaling pathways, however, the disease outcome and effect is different among them. In this review, we discuss the approaches of these apicomplexan to manipulate the host–parasite clearance pathways during infection, invasion, survival, and egress. PMID:29081773

Hepatitis B virus molecular biology and pathogenesis

PubMed Central

Lamontagne, R. Jason; Bagga, Sumedha; Bouchard, Michael J.

2016-01-01

As obligate intracellular parasites, viruses need a host cell to provide a milieu favorable to viral replication. Consequently, viruses often adopt mechanisms to subvert host cellular signaling processes. While beneficial for the viral replication cycle, virus-induced deregulation of host cellular signaling processes can be detrimental to host cell physiology and can lead to virus-associated pathogenesis, including, for oncogenic viruses, cell transformation and cancer progression. Included among these oncogenic viruses is the hepatitis B virus (HBV). Despite the availability of an HBV vaccine, 350–500 million people worldwide are chronically infected with HBV, and a significant number of these chronically infected individuals will develop hepatocellular carcinoma (HCC). Epidemiological studies indicate that chronic infection with HBV is the leading risk factor for the development of HCC. Globally, HCC is the second highest cause of cancer-associated deaths, underscoring the need for understanding mechanisms that regulate HBV replication and the development of HBV-associated HCC. HBV is the prototype member of the Hepadnaviridae family; members of this family of viruses have a narrow host range and predominately infect hepatocytes in their respective hosts. The extremely small and compact hepadnaviral genome, the unique arrangement of open reading frames, and a replication strategy utilizing reverse transcription of an RNA intermediate to generate the DNA genome are distinguishing features of the Hepadnaviridae. In this review, we provide a comprehensive description of HBV biology, summarize the model systems used for studying HBV infections, and highlight potential mechanisms that link a chronic HBV-infection to the development of HCC. For example, the HBV X protein (HBx), a key regulatory HBV protein that is important for HBV replication, is thought to play a cofactor role in the development of HBV-induced HCC, and we highlight the functions of HBx that may contribute to the development of HBV-associated HCC. PMID:28042609

Specialized metabolites from the microbiome in health and disease

PubMed Central

Sharon, Gil; Garg, Neha; Debelius, Justine; Knight, Rob; Dorrestein, Pieter C.; Mazmanian, Sarkis K.

2015-01-01

The microbiota, and the genes that comprise its microbiome, play key roles in human health. Host-microbe interactions affect immunity, metabolism, development, and behavior, and dysbiosis of gut bacteria contributes to disease. Despite advances in correlating changes in the microbiota with various conditions, specific mechanisms of host-microbiota signaling remain largely elusive. We discuss the synthesis of microbial metabolites, their absorption, and potential physiological effects on the host. We propose that the effects of specialized metabolites may explain present knowledge gaps linking the gut microbiota to biological host mechanisms during initial colonization, and in health and disease. PMID:25440054

Host behaviour and physiology underpin individual variation in avian influenza virus infection in migratory Bewick's swans.

PubMed

Hoye, Bethany J; Fouchier, Ron A M; Klaassen, Marcel

2012-02-07

Individual variation in infection modulates both the dynamics of pathogens and their impact on host populations. It is therefore crucial to identify differential patterns of infection and understand the mechanisms responsible. Yet our understanding of infection heterogeneity in wildlife is limited, even for important zoonotic host-pathogen systems, owing to the intractability of host status prior to infection. Using novel applications of stable isotope ecology and eco-immunology, we distinguish antecedent behavioural and physiological traits associated with avian influenza virus (AIV) infection in free-living Bewick's swans (Cygnus columbianus bewickii). Swans infected with AIV exhibited higher serum δ13C (-25.3±0.4) than their non-infected counterparts (-26.3±0.2). Thus, individuals preferentially foraging in aquatic rather than terrestrial habitats experienced a higher risk of infection, suggesting that the abiotic requirements of AIV give rise to heterogeneity in pathogen exposure. Juveniles were more likely to be infected (30.8% compared with 11.3% for adults), shed approximately 15-fold higher quantity of virus and exhibited a lower specific immune response than adults. Together, these results demonstrate the potential for heterogeneity in infection to have a profound influence on the dynamics of pathogens, with concomitant impacts on host habitat selection and fitness.

Chapter 5. Damage, effects, and importance of dwarf mistletoes

Treesearch

B. W. Geils; F. G. Hawksworth

2002-01-01

All dwarf mistletoes are parasites that extract water, nutrients, and carbohydrates from the infected host; they are also pathogens that alter host physiology and morphology (Gill and Hawksworth 1961, Hawksworth and Wiens 1996). Disease or direct effects are reductions in diameter and height increment, survival, reproduction, and quality; witches’ brooms are formed in...

Targeting physiological activities to modify the ecology and functionality of rumen and gastrointestinal ecosystems, prototypical anaerobic digester

USDA-ARS?s Scientific Manuscript database

The rumen microbial ecosystem is highly regarded for its ability to digest and transform low quality plant material into chemical forms of use by the host. However, less than 35% of the dietary energy consumed by the ruminant is conserved by the host. Methane production within the rumen contribute...

The effects of Phytophthora ramorum stem inoculation on aspects of tanoak physiology and xylem function in saplings and seedlings

Treesearch

Elizabeth Stamm

2012-01-01

Phytophthora ramorum, an oomycete plant pathogen, is the causal agent of sudden oak death, a serious disease of Fagaceous trees in California and Oregon over the last decade. Tanoak (Notholithocarpus densiflorus) is one of the most susceptible host species, but the cause of host mortality is poorly understood....

Use of Genetically-encoded Calcium Indicators for Live Cell Calcium Imaging and Localization in Virus-infected Cells

PubMed Central

Perry, Jacob L.; Ramachandran, Nina K.; Utama, Budi; Hyser, Joseph M.

2015-01-01

Calcium signaling is a ubiquitous and versatile process involved in nearly every cellular process, and exploitation of host calcium signals is a common strategy used by viruses to facilitate replication and cause disease. Small molecule fluorescent calcium dyes have been used by many to examine changes in host cell calcium signaling and calcium channel activation during virus infections, but disadvantages of these dyes, including poor loading and poor long-term retention, complicate analysis of calcium imaging in virus-infected cells due to changes in cell physiology and membrane integrity. The recent expansion of genetically-encoded calcium indicators (GECIs), including blue and red-shifted color variants and variants with calcium affinities appropriate for calcium storage organelles like the endoplasmic reticulum (ER), make the use of GECIs an attractive alternative for calcium imaging in the context of virus infections. Here we describe the development and testing of cell lines stably expressing both green cytoplasmic (GCaMP5G and GCaMP6s) and red ER-targeted (RCEPIAer) GECIs. Using three viruses (rotavirus, poliovirus and respiratory syncytial virus) previously shown to disrupt host calcium homeostasis, we show the GECI cell lines can be used to detect simultaneous cytoplasmic and ER calcium signals. Further, we demonstrate the GECI expression has sufficient stability to enable long-term confocal imaging of both cytoplasmic and ER calcium during the course of virus infections. PMID:26344758

Mechanistic Oral Absorption Modeling and Simulation for Formulation Development and Bioequivalence Evaluation: Report of an FDA Public Workshop

PubMed Central

Duan, J; Kesisoglou, F; Novakovic, J; Amidon, GL; Jamei, M; Lukacova, V; Eissing, T; Tsakalozou, E; Zhao, L; Lionberger, R

2017-01-01

On May 19, 2016, the US Food and Drug Administration (FDA) hosted a public workshop, entitled “Mechanistic Oral Absorption Modeling and Simulation for Formulation Development and Bioequivalence Evaluation.”1 The topic of mechanistic oral absorption modeling, which is one of the major applications of physiologically based pharmacokinetic (PBPK) modeling and simulation, focuses on predicting oral absorption by mechanistically integrating gastrointestinal transit, dissolution, and permeation processes, incorporating systems, active pharmaceutical ingredient (API), and the drug product information, into a systemic mathematical whole‐body framework.2 PMID:28571121

[Signaling Systems of Rhizobia (Rhizobiaceae) and Leguminous Plants (Fabaceae) upon the Formation of a Legume-Rhizobium Symbiosis (Review)].

PubMed

Glyan'ko, A K

2015-01-01

Data from the literature and our own data on the participation and interrelation of bacterial signaling Nod-factors and components of the calcium, NADPH-oxidase, and NO-synthase signaling systems of a plant at the preinfection and infectious stages of the formation of a legume-rhizobium symbiosis are summarized in this review. The physiological role of Nod-factors, reactive oxygen species (ROS), calcium (Ca2+), NADPH-oxidase, nitric oxide (NO), and their cross influence on the processes determining the formation of symbiotic structures on the roots of the host plant is discussed.

Transcriptional targets in adipocyte biology

PubMed Central

Rosen, Evan; Eguchi, Jun; Xu, Zhao

2010-01-01

The global burden of metabolic disease demands that we develop new therapeutic strategies. Many of these approaches may center on manipulating the behavior of adipocytes, which contribute directly and indirectly to a host of disease processes including obesity and type 2 diabetes. One way to achieve this goal will be to alter key transcriptional pathways in fat cells, such as those regulating glucose uptake, lipid handling, or adipokine secretion. In this review we look at what is known about how adipocytes govern their physiology at the gene expression level, and we discuss novel ways that we can accelerate our understanding of this area. PMID:19534570

Zebra Chip disease and potato biochemistry: Tuber physiological changes in response to ‘Candidatus Liberibacter solanacearum’ infection over time

USDA-ARS?s Scientific Manuscript database

Zebra chip disease (ZC), putatively caused by ‘Candidatus Liberibacter solanacearum’ (Lso), is of increasing concern to potato production in Mexico, the United States, and New Zealand. However, little is known about host tuber physiological changes that result in ZC symptom formation. This study exp...

The LOV Protein of Xanthomonas citri subsp. citri Plays a Significant Role in the Counteraction of Plant Immune Responses during Citrus Canker

PubMed Central

Kraiselburd, Ivana; Daurelio, Lucas D.; Tondo, María Laura; Merelo, Paz; Cortadi, Adriana A.; Talón, Manuel; Tadeo, Francisco R.; Orellano, Elena G.

2013-01-01

Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. The ability of this bacterium to colonize host plants is influenced by bacterial blue-light sensing through a LOV-domain protein and disease symptoms are considerably altered upon deletion of this protein. In this work we aimed to unravel the role of this photoreceptor during the bacterial counteraction of plant immune responses leading to citrus canker development. We performed a transcriptomic analysis in Citrus sinensis leaves inoculated with the wild type X. citri subsp. citri and with a mutant strain lacking the LOV protein by a cDNA microarray and evaluated the differentially regulated genes corresponding to specific biological processes. A down-regulation of photosynthesis-related genes (together with a corresponding decrease in photosynthesis rates) was observed upon bacterial infection, this effect being more pronounced in plants infected with the lov-mutant bacterial strain. Infection with this strain was also accompanied with the up-regulation of several secondary metabolism- and defense response-related genes. Moreover, we found that relevant plant physiological alterations triggered by pathogen attack such as cell wall fortification and tissue disruption were amplified during the lov-mutant strain infection. These results suggest the participation of the LOV-domain protein from X. citri subsp. citri in the bacterial counteraction of host plant defense response, contributing in this way to disease development. PMID:24260514

Mucin acts as a nutrient source and a signal for the differential expression of genes coding for cellular processes and virulence factors in Acinetobacter baumannii

PubMed Central

Ohneck, Emily J.; Arivett, Brock A.; Fiester, Steven E.; Wood, Cecily R.; Metz, Maeva L.; Simeone, Gabriella M.

2018-01-01

The capacity of Acinetobacter baumannii to persist and cause infections depends on its interaction with abiotic and biotic surfaces, including those found on medical devices and host mucosal surfaces. However, the extracellular stimuli affecting these interactions are poorly understood. Based on our previous observations, we hypothesized that mucin, a glycoprotein secreted by lung epithelial cells, particularly during respiratory infections, significantly alters A. baumannii’s physiology and its interaction with the surrounding environment. Biofilm, virulence and growth assays showed that mucin enhances the interaction of A. baumannii ATCC 19606T with abiotic and biotic surfaces and its cytolytic activity against epithelial cells while serving as a nutrient source. The global effect of mucin on the physiology and virulence of this pathogen is supported by RNA-Seq data showing that its presence in a low nutrient medium results in the differential transcription of 427 predicted protein-coding genes. The reduced expression of ion acquisition genes and the increased transcription of genes coding for energy production together with the detection of mucin degradation indicate that this host glycoprotein is a nutrient source. The increased expression of genes coding for adherence and biofilm biogenesis on abiotic and biotic surfaces, the degradation of phenylacetic acid and the production of an active type VI secretion system further supports the role mucin plays in virulence. Taken together, our observations indicate that A. baumannii recognizes mucin as an environmental signal, which triggers a response cascade that allows this pathogen to acquire critical nutrients and promotes host-pathogen interactions that play a role in the pathogenesis of bacterial infections. PMID:29309434

Functional Roles of p38 Mitogen-Activated Protein Kinase in Macrophage-Mediated Inflammatory Responses

PubMed Central

Yang, Yanyan; Yu, Tao; Sung, Gi-Ho; Yoo, Byong Chul

2014-01-01

Inflammation is a natural host defensive process that is largely regulated by macrophages during the innate immune response. Mitogen-activated protein kinases (MAPKs) are proline-directed serine and threonine protein kinases that regulate many physiological and pathophysiological cell responses. p38 MAPKs are key MAPKs involved in the production of inflammatory mediators, including tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2). p38 MAPK signaling plays an essential role in regulating cellular processes, especially inflammation. In this paper, we summarize the characteristics of p38 signaling in macrophage-mediated inflammation. In addition, we discuss the potential of using inhibitors targeting p38 expression in macrophages to treat inflammatory diseases. PMID:24771982

White-nose syndrome initiates a cascade of physiologic disturbances in the hibernating bat host

USGS Publications Warehouse

Verant, Michelle L.; Meteyer, Carol U.; Speakman, John R.; Cryan, Paul M.; Lorch, Jeffrey M.; Blehert, David S.

2014-01-01

Integrating these novel findings on the physiological changes that occur in early-stage WNS with those previously documented in late-stage infections, we propose a multi-stage disease progression model that mechanistically describes the pathologic and physiologic effects underlying mortality of WNS in hibernating bats. This model identifies testable hypotheses for better understanding this disease, knowledge that will be critical for defining effective disease mitigation strategies aimed at reducing morbidity and mortality that results from WNS.

Identification and Comparative Study of Chemosensory Genes Related to Host Selection by Legs Transcriptome Analysis in the Tea Geometrid Ectropis obliqua

PubMed Central

Bian, Lei; Cai, Xiao-Ming; Luo, Zong-Xiu; Zhang, Yong-Jun; Chen, Zong-Mao

2016-01-01

Host selection by female moths is fundamental to the survival of their larvae. Detecting and perceiving the non-volatile chemicals of the plant surface involved in gustatory detection determine the host preference. In many lepidopteran species, tarsal chemosensilla are sensitive to non-volatile chemicals and responsible for taste detection. The tea geometrid Ectropis obliqua is one devastating chewing pest selectively feeding on limited plants, requiring the specialized sensors to forage certain host for oviposition. In present study, we revealed the distribution of chemosensilla in the ventral side of female fifth tarsomere in E. obliqua. To investigate its molecular mechanism of gustatory perception, we performed HiSeq 2500 sequencing of the male- and female- legs transcriptome and identified 24 candidate odorant binding proteins (OBPs), 21 chemosensory proteins (CSPs), 2 sensory neuron membrane proteins (SNMPs), 3 gustatory receptors (GRs) and 4 odorant receptors (ORs). Several leg-specific or enriched chemosensory genes were screened by tissue expression analysis, and clustered with functionally validated genes from other moths, suggesting the potential involvement in taste sensation or other physiological processes. The RPKM value analysis revealed that 9 EoblOBPs showed sex discrepancy in the leg expression, 8 being up-regulated in female and only 1 being over expressed in male. These female-biased EoblOBPs indicated an ecological adaption related with host-seeking and oviposition behaviors. Our work will provide basic knowledge for further studies on the molecular mechanism of gustatory perception, and enlighten a host-selection-based control strategy of insect pests. PMID:26930056

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

PubMed Central

Brencic, Anja; Winans, Stephen C.

2005-01-01

Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described. PMID:15755957

Immunological roulette: Luck or something more? Considering the connections between host and environment in TB.

PubMed

Pearl, John E; Das, Mrinal; Cooper, Andrea M

2018-03-01

Accurate prediction of which patient will progress from a sub-clinical Mycobacterium tuberculosis infection to active tuberculosis represents an elusive, yet critical, clinical research objective. From the individual perspective, progression can be considered to be the product of a series of unfortunate events or even a run of bad luck. Here, we identify the subtle physiological relationships that can influence the odds of progression to active TB and how this progression may reflect directed dysbiosis in a number of interrelated systems. Most infected individuals who progress to disease have apparently good immune responses, but these responses are, at times, compromised by either local or systemic environmental factors. Obvious disease promoting processes, such as tissue-damaging granulomata, usually manifest in the lung, but illness is systemic. This apparent dichotomy between local and systemic reflects a clear need to define the factors that promote progression to active disease within the context of the body as a physiological whole. We discuss aspects of the host environment that can impact expression of immunity, including the microbiome, glucocorticoid-mediated regulation, catecholamines and interaction between the gut, liver and lung. We suggest the importance of integrating precision medicine into our analyses of experimental outcomes such that apparently conflicting results are not contentious, but rather reflect the impact of these subtle relationships with our environment and microbiota.

Host plant-specific remodeling of midgut physiology in the generalist insect herbivore Trichoplusia ni.

PubMed

Herde, Marco; Howe, Gregg A

2014-07-01

Species diversity in terrestrial ecosystems is influenced by plant defense compounds that alter the behavior, physiology, and host preference of insect herbivores. Although it is established that insects evolved the ability to detoxify specific allelochemicals, the mechanisms by which polyphagous insects cope with toxic compounds in diverse host plants are not well understood. Here, we used defended and non-defended plant genotypes to study how variation in chemical defense affects midgut responses of the lepidopteran herbivore Trichoplusia ni, which is a pest of a wide variety of native and cultivated plants. The genome-wide midgut transcriptional response of T. ni larvae to glucosinolate-based defenses in the crucifer Arabidopsis thaliana was characterized by strong induction of genes encoding Phase I and II detoxification enzymes. In contrast, the response of T. ni to proteinase inhibitors and other jasmonate-regulated defenses in tomato (Solanum lycopersicum) was dominated by changes in the expression of digestive enzymes and, strikingly, concomitant repression of transcripts encoding detoxification enzymes. Unbiased proteomic analyses of T. ni feces demonstrated that tomato defenses remodel the complement of T.ni digestive enzymes, which was associated with increased amounts of serine proteases and decreased lipase protein abundance upon encountering tomato defense chemistry. These collective results indicate that T. ni adjusts its gut physiology to the presence of host plant-specific chemical defenses, and further suggest that plants may exploit this digestive flexibility as a defensive strategy to suppress the production of enzymes that detoxify allelochemicals. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Physiology of Phagocytosis in the Context of Mitochondrial Origin

PubMed Central

Tielens, Aloysius G. M.; Mentel, Marek

2017-01-01

SUMMARY How mitochondria came to reside within the cytosol of their host has been debated for 50 years. Though current data indicate that the last eukaryote common ancestor possessed mitochondria and was a complex cell, whether mitochondria or complexity came first in eukaryotic evolution is still discussed. In autogenous models (complexity first), the origin of phagocytosis poses the limiting step at eukaryote origin, with mitochondria coming late as an undigested growth substrate. In symbiosis-based models (mitochondria first), the host was an archaeon, and the origin of mitochondria was the limiting step at eukaryote origin, with mitochondria providing bacterial genes, ATP synthesis on internalized bioenergetic membranes, and mitochondrion-derived vesicles as the seed of the eukaryote endomembrane system. Metagenomic studies are uncovering new host-related archaeal lineages that are reported as complex or phagocytosing, although images of such cells are lacking. Here we review the physiology and components of phagocytosis in eukaryotes, critically inspecting the concept of a phagotrophic host. From ATP supply and demand, a mitochondrion-lacking phagotrophic archaeal fermenter would have to ingest about 34 times its body weight in prokaryotic prey to obtain enough ATP to support one cell division. It would lack chemiosmotic ATP synthesis at the plasma membrane, because phagocytosis and chemiosmosis in the same membrane are incompatible. It would have lived from amino acid fermentations, because prokaryotes are mainly protein. Its ATP yield would have been impaired relative to typical archaeal amino acid fermentations, which involve chemiosmosis. In contrast, phagocytosis would have had great physiological benefit for a mitochondrion-bearing cell. PMID:28615286

Getting ready for host invasion: elevated expression and action of xyloglucan endotransglucosylases/hydrolases in developing haustoria of the holoparasitic angiosperm Cuscuta

PubMed Central

Olsen, Stian; Striberny, Bernd; Hollmann, Julien; Schwacke, Rainer; Popper, Zoë; Krause, Kirsten

2016-01-01

Changes in cell walls have been previously observed in the mature infection organ, or haustorium, of the parasitic angiosperm Cuscuta, but are not equally well charted in young haustoria. In this study, we focused on the molecular processes in the early stages of developing haustoria; that is, before the parasite engages in a physiological contact with its host. We describe first the identification of differentially expressed genes in young haustoria whose development was induced by far-red light and tactile stimuli in the absence of a host plant by suppression subtractive hybridization. To improve sequence information and to aid in the identification of the obtained candidates, reference transcriptomes derived from two species of Cuscuta, C. gronovii and C. reflexa, were generated. Subsequent quantitative gene expression analysis with different tissues of C. reflexa revealed that among the genes that were up-regulated in young haustoria, two xyloglucan endotransglucosylase/hydrolase (XTH) genes were highly expressed almost exclusively at the onset of haustorium development. The same expression pattern was also found for the closest XTH homologues from C. gronovii. In situ assays for XTH-specific action suggested that xyloglucan endotransglucosylation was most pronounced in the cell walls of the swelling area of the haustorium facing the host plant, but was also detectable in later stages of haustoriogenesis. We propose that xyloglucan remodelling by Cuscuta XTHs prepares the parasite for host infection and possibly aids the invasive growth of the haustorium. PMID:26561437

Targeting the gut microbiota by dietary nutrients: A new avenue for human health.

PubMed

Li, Daotong; Wang, Pan; Wang, Pengpu; Hu, Xiaosong; Chen, Fang

2017-08-28

The gut microbiota is a complex ecosystem consisted of trillions of microbes that have co-evolved with their host for hundreds of millions of years. During the last decade, a growing body of knowledge has suggested that there is a compelling set of connections among diet, gut microbiota and human health. Various physiological functions of the host, ranging from metabolic and immune regulation to nerve and endocrine development, are possibly mediated by the structural components of microbial cell or the products of microbial metabolism, which are greatly influenced by dietary macronutrients and micronutrients. Thus, governing the production and activity of these microbial-associated small molecules and metabolites through dietary intervention may provide promising strategies for the improvement of human health and disease. In this review article, we first provide an overview of current findings about the intimate interrelationships between diet and gut microbiota. We also introduce the physiological effects of some microbial-associated small molecules and metabolites on the host as well as the detailed signaling mechanisms.

[Isolation and physiological characteristics of endophytic actinobacteria from medicinal plants].

PubMed

Du, Huijing; Su, Jing; Yu, Liyan; Zhang, Yuqin

2013-01-04

To isolate, incubate and characterize cultivable endophytic antinobacteria from medicinal plants, and analyze the diversity of the endophytic antinobacteria, then explore the novel microbial resources. Ten media were used to isolate endophytic antinobacteria from 37 fresh medicinal plant tissue samples. The optimal cultivation conditions for endophytic antinobacteria were determined by comparison. Based on the morphology of the colonies and cells of the new isolates, we chose 174 isolates to analyze their 16S rRNA gene sequences and the diversity of the medicinal plant endophytic antinobacteria. The physiological characteristics of 27 representative strains were studied using Biolog GEN III MicroPlates, API 50CH and API ZYM kits. In total 940 endophytics affiliated to 47 genera of 30 families were isolated, among which more than 600 actinobacteria belonged to 34 genera and 7 unknown taxa. Good growth of the endophytic antinobacteria on PYG (peptone-yeast-glycerol) medium with pH 7.2 at 28-32 degrees C was observed. Physiological characteristics differences of these isolates related to their phylogenetic relationships. Greater differences were shown among the strains from the same host plants than those from differ,ent plants grown in the same area. There are great diverse endophytic actinobacteria inside the medicinal plants. No direct relationship of the endophytic actinobacteria from medicinal plants with the host plants in the sole carbon source utilization, fermentation of carbon sources to produce acid and the enzyme activities was found, while it seemed that the physiological characteristics of the isolates related to the geographical distribution of their host.

Commensal bacteria produce GPCR ligands that mimic human signaling molecules

PubMed Central

Cohen, Louis J.; Esterhazy, Daria; Kim, Seong-Hwan; Lemetre, Christophe; Aguilar, Rhiannon R.; Gordon, Emma A.; Pickard, Amanda J.; Cross, Justin R.; Emiliano, Ana B.; Han, Sun M.; Chu, John; Vila-Farres, Xavier; Kaplitt, Jeremy; Rogoz, Aneta; Calle, Paula Y.; Hunter, Craig; Bitok, J. Kipchirchir; Brady, Sean F.

2017-01-01

Summary Statement Commensal bacteria are believed to play important roles in human health. The mechanisms by which they affect mammalian physiology are poorly understood; however, bacterial metabolites are likely to be key components of host interactions. Here, we use bioinformatics and synthetic biology to mine the human microbiota for N-acyl amides that interact with G-protein-coupled receptors (GPCRs). We found that N-acyl amide synthase genes are enriched in gastrointestinal bacteria and the lipids they encode interact with GPCRs that regulate gastrointestinal tract physiology. Mouse and cell-based models demonstrate that commensal GPR119 agonists regulate metabolic hormones and glucose homeostasis as efficiently as human ligands although future studies are needed to define their potential physiologic role in humans. This work suggests that chemical mimicry of eukaryotic signaling molecules may be common among commensal bacteria and that manipulation of microbiota genes encoding metabolites that elicit host cellular responses represents a new small molecule therapeutic modality (microbiome-biosynthetic-gene-therapy). PMID:28854168

Upregulation of zinc absorption matches increases in physiological requirements for zinc in women consuming high-or-moderate-phytate diets during late pregnancy and early lactation

USDA-ARS?s Scientific Manuscript database

Objectives: To determine the roles of host and dietary factors in matching increases in physiological requirements for zinc (Zn) during late pregnancy and early lactation in women whose major dietary staple is maize with and without phytate reduction. Methods: Subjects were 22 indigenous Guatemalan ...

Variable responses of human and non-human primate gut microbiomes to a Western diet.

PubMed

Amato, Katherine R; Yeoman, Carl J; Cerda, Gabriela; Schmitt, Christopher A; Cramer, Jennifer Danzy; Miller, Margret E Berg; Gomez, Andres; Turner, Trudy R; Wilson, Brenda A; Stumpf, Rebecca M; Nelson, Karen E; White, Bryan A; Knight, Rob; Leigh, Steven R

2015-11-16

The human gut microbiota interacts closely with human diet and physiology. To better understand the mechanisms behind this relationship, gut microbiome research relies on complementing human studies with manipulations of animal models, including non-human primates. However, due to unique aspects of human diet and physiology, it is likely that host-gut microbe interactions operate differently in humans and non-human primates. Here, we show that the human microbiome reacts differently to a high-protein, high-fat Western diet than that of a model primate, the African green monkey, or vervet (Chlorocebus aethiops sabaeus). Specifically, humans exhibit increased relative abundance of Firmicutes and reduced relative abundance of Prevotella on a Western diet while vervets show the opposite pattern. Predictive metagenomics demonstrate an increased relative abundance of genes associated with carbohydrate metabolism in the microbiome of only humans consuming a Western diet. These results suggest that the human gut microbiota has unique properties that are a result of changes in human diet and physiology across evolution or that may have contributed to the evolution of human physiology. Therefore, the role of animal models for understanding the relationship between the human gut microbiota and host metabolism must be re-focused.

Seed germination in parasitic plants: what insights can we expect from strigolactone research?

PubMed

Brun, Guillaume; Braem, Lukas; Thoiron, Séverine; Gevaert, Kris; Goormachtig, Sofie; Delavault, Philippe

2018-04-23

Obligate root-parasitic plants belonging to the Orobanchaceae family are deadly pests for major crops all over the world. Because these heterotrophic plants severely damage their hosts even before emerging from the soil, there is an unequivocal need to design early and efficient methods for their control. The germination process of these species has probably undergone numerous selective pressure events in the course of evolution, in that the perception of host-derived molecules is a necessary condition for seeds to germinate. Although most of these molecules belong to the strigolactones, structurally different molecules have been identified. Since strigolactones are also classified as novel plant hormones that regulate several physiological processes other than germination, the use of autotrophic model plant species has allowed the identification of many actors involved in the strigolactone biosynthesis, perception, and signal transduction pathways. Nevertheless, many questions remain to be answered regarding the germination process of parasitic plants. For instance, how did parasitic plants evolve to germinate in response to a wide variety of molecules, while autotrophic plants do not? What particular features are associated with their lack of spontaneous germination? In this review, we attempt to illustrate to what extent conclusions from research into strigolactones could be applied to better understand the biology of parasitic plants.

AmapSim: a structural whole-plant simulator based on botanical knowledge and designed to host external functional models.

PubMed

Barczi, Jean-François; Rey, Hervé; Caraglio, Yves; de Reffye, Philippe; Barthélémy, Daniel; Dong, Qiao Xue; Fourcaud, Thierry

2008-05-01

AmapSim is a tool that implements a structural plant growth model based on a botanical theory and simulates plant morphogenesis to produce accurate, complex and detailed plant architectures. This software is the result of more than a decade of research and development devoted to plant architecture. New advances in the software development have yielded plug-in external functions that open up the simulator to functional processes. The simulation of plant topology is based on the growth of a set of virtual buds whose activity is modelled using stochastic processes. The geometry of the resulting axes is modelled by simple descriptive functions. The potential growth of each bud is represented by means of a numerical value called physiological age, which controls the value for each parameter in the model. The set of possible values for physiological ages is called the reference axis. In order to mimic morphological and architectural metamorphosis, the value allocated for the physiological age of buds evolves along this reference axis according to an oriented finite state automaton whose occupation and transition law follows a semi-Markovian function. Simulations were performed on tomato plants to demonstrate how the AmapSim simulator can interface external modules, e.g. a GREENLAB growth model and a radiosity model. The algorithmic ability provided by AmapSim, e.g. the reference axis, enables unified control to be exercised over plant development parameter values, depending on the biological process target: how to affect the local pertinent process, i.e. the pertinent parameter(s), while keeping the rest unchanged. This opening up to external functions also offers a broadened field of applications and thus allows feedback between plant growth and the physical environment.

AmapSim: A Structural Whole-plant Simulator Based on Botanical Knowledge and Designed to Host External Functional Models

PubMed Central

Barczi, Jean-François; Rey, Hervé; Caraglio, Yves; de Reffye, Philippe; Barthélémy, Daniel; Dong, Qiao Xue; Fourcaud, Thierry

2008-01-01

Background and Aims AmapSim is a tool that implements a structural plant growth model based on a botanical theory and simulates plant morphogenesis to produce accurate, complex and detailed plant architectures. This software is the result of more than a decade of research and development devoted to plant architecture. New advances in the software development have yielded plug-in external functions that open up the simulator to functional processes. Methods The simulation of plant topology is based on the growth of a set of virtual buds whose activity is modelled using stochastic processes. The geometry of the resulting axes is modelled by simple descriptive functions. The potential growth of each bud is represented by means of a numerical value called physiological age, which controls the value for each parameter in the model. The set of possible values for physiological ages is called the reference axis. In order to mimic morphological and architectural metamorphosis, the value allocated for the physiological age of buds evolves along this reference axis according to an oriented finite state automaton whose occupation and transition law follows a semi-Markovian function. Key Results Simulations were performed on tomato plants to demostrate how the AmapSim simulator can interface external modules, e.g. a GREENLAB growth model and a radiosity model. Conclusions The algorithmic ability provided by AmapSim, e.g. the reference axis, enables unified control to be exercised over plant development parameter values, depending on the biological process target: how to affect the local pertinent process, i.e. the pertinent parameter(s), while keeping the rest unchanged. This opening up to external functions also offers a broadened field of applications and thus allows feedback between plant growth and the physical environment. PMID:17766310

Multi‐omic profiling ­of EPO‐producing Chinese hamster ovary cell panel reveals metabolic adaptation to heterologous protein production

PubMed Central

Ley, Daniel; Seresht, Ali Kazemi; Engmark, Mikael; Magdenoska, Olivera; Nielsen, Kristian Fog; Kildegaard, Helene Faustrup

2015-01-01

ABSTRACT Chinese hamster ovary (CHO) cells are the preferred production host for many therapeutic proteins. The production of heterologous proteins in CHO cells imposes a burden on the host cell metabolism and impact cellular physiology on a global scale. In this work, a multi‐omics approach was applied to study the production of erythropoietin (EPO) in a panel of CHO‐K1 cells under growth‐limited and unlimited conditions in batch and chemostat cultures. Physiological characterization of the EPO‐producing cells included global transcriptome analysis, targeted metabolome analysis, including intracellular pools of glycolytic intermediates, NAD(P)H/NAD(P)+, adenine nucleotide phosphates (ANP), and extracellular concentrations of sugars, organic acids, and amino acids. Potential impact of EPO expression on the protein secretory pathway was assessed at multiple stages using quantitative PCR (qPCR), reverse transcription PCR (qRT‐PCR), Western blots (WB), and global gene expression analysis to assess EPO gene copy numbers, EPO gene expression, intracellular EPO retention, and differentially expressed genes functionally related to secretory protein processing, respectively. We found no evidence supporting the existence of production bottlenecks in energy metabolism (i.e., glycolytic metabolites, NAD(P)H/NAD(P)+ and ANPs) in batch culture or in the secretory protein production pathway (i.e., gene dosage, transcription and post‐translational processing of EPO) in chemostat culture at specific productivities up to 5 pg/cell/day. Time‐course analysis of high‐ and low‐producing clones in chemostat culture revealed rapid adaptation of transcription levels of amino acid catabolic genes in favor of EPO production within nine generations. Interestingly, the adaptation was followed by an increase in specific EPO productivity. Biotechnol. Bioeng. 2015;112: 2373–2387. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:25995028

Chitinase-like proteins as regulators of innate immunity and tissue repair: helpful lessons for asthma?

PubMed

Sutherland, Tara E

2018-02-19

Chitinases and chitinase-like proteins (CLPs) belong to the glycoside hydrolase family 18 of proteins. Chitinases are expressed in mammals and lower organisms, facilitate chitin degradation, and hence act as host-defence enzymes. Gene duplication and loss-of-function mutations of enzymatically active chitinases have resulted in the expression of a diverse range of CLPs across different species. CLPs are genes that are increasingly associated with inflammation and tissue remodelling not only in mammals but also across distant species. While the focus has remained on understanding the functions and expression patterns of CLPs during disease in humans, studies in mouse and lower organisms have revealed important and overlapping roles of the CLP family during physiology, host defence and pathology. This review will summarise recent insights into the regulatory functions of CLPs on innate immune pathways and discuss how these effects are not only important for host defence and tissue injury/repair after pathogen invasion, but also how they have extensive implications for pathological processes involved in diseases such as asthma. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Pathophysiological role of host microbiota in the development of obesity.

PubMed

Kobyliak, Nazarii; Virchenko, Oleksandr; Falalyeyeva, Tetyana

2016-04-23

Overweight and obesity increase the risk for a number of diseases, namely, cardiovascular diseases, type 2 diabetes, dyslipidemia, premature death, non-alcoholic fatty liver disease as well as different types of cancer. Approximately 1.7 billion people in the world suffer from being overweight, most notably in developed countries. Current research efforts have focused on host and environmental factors that may affect energy balance. It was hypothesized that a microbiota profile specific to an obese host with increased energy-yielding behavior may exist. Consequently, the gut microbiota is becoming of significant research interest in relation to obesity in an attempt to better understand the aetiology of obesity and to develop new methods of its prevention and treatment. Alteration of microbiota composition may stimulate development of obesity and other metabolic diseases via several mechanisms: increasing gut permeability with subsequent metabolic inflammation; increasing energy harvest from the diet; impairing short-chain fatty acids synthesis; and altering bile acids metabolism and FXR/TGR5 signaling. Prebiotics and probiotics have physiologic functions that contribute to the health of gut microbiota, maintenance of a healthy body weight and control of factors associated with obesity through their effects on mechanisms that control food intake, body weight, gut microbiota and inflammatory processes.

Strigolactones and root infestation by plant-parasitic Striga, Orobanche and Phelipanche spp.

PubMed

Cardoso, Catarina; Ruyter-Spira, Carolien; Bouwmeester, Harro J

2011-03-01

Strigolactones are signaling molecules that play a role in host recognition by parasitic plants of the Striga, Orobanche and Phelipanche genera which are among the most detrimental weeds in agriculture. The same class of molecules is also involved in the establishment of the symbiosis of plants with arbuscular mycorrhizal (AM) fungi. In addition, the strigolactones are being shown to be involved in an increasing number of physiological processes in plants, such as the regulation of plant architecture and the response to abiotic factors such as nutrient availability and light. These new findings suggest that biosynthesis and perception of strigolactones are conserved throughout the plant kingdom. The structural variation in the strigolactones discovered so far and its possible role in host recognition by the parasites and AM fungi as well as the evolution of strigolactone-dependent-germination in parasitic plants will be discussed. Finally, due to the recent advance in strigolactone research, new insights are emerging on the relation between parasitic and host plants which may result in new strategies to control parasitic plant infestation that will be discussed in this review. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Small RNA-based feedforward loop with AND-gate logic regulates extrachromosomal DNA transfer in Salmonella.

PubMed

Papenfort, Kai; Espinosa, Elena; Casadesús, Josep; Vogel, Jörg

2015-08-25

Horizontal gene transfer via plasmid conjugation is a major driving force in microbial evolution but constitutes a complex process that requires synchronization with the physiological state of the host bacteria. Although several host transcription factors are known to regulate plasmid-borne transfer genes, RNA-based regulatory circuits for host-plasmid communication remain unknown. We describe a posttranscriptional mechanism whereby the Hfq-dependent small RNA, RprA, inhibits transfer of pSLT, the virulence plasmid of Salmonella enterica. RprA employs two separate seed-pairing domains to activate the mRNAs of both the sigma-factor σ(S) and the RicI protein, a previously uncharacterized membrane protein here shown to inhibit conjugation. Transcription of ricI requires σ(S) and, together, RprA and σ(S) orchestrate a coherent feedforward loop with AND-gate logic to tightly control the activation of RicI synthesis. RicI interacts with the conjugation apparatus protein TraV and limits plasmid transfer under membrane-damaging conditions. To our knowledge, this study reports the first small RNA-controlled feedforward loop relying on posttranscriptional activation of two independent targets and an unexpected role of the conserved RprA small RNA in controlling extrachromosomal DNA transfer.

Gut Microbiota and IGF-1.

PubMed

Yan, Jing; Charles, Julia F

2018-04-01

Microbiota and their hosts have coevolved for millions of years. Microbiota are not only critical for optimal development of the host under normal physiological growth, but also important to ensure proper host development during nutrient scarcity or disease conditions. A large body of research has begun to detail the mechanism(s) of how microbiota cooperate with the host to maintain optimal health status. One crucial host pathway recently demonstrated to be modulated by microbiota is that of the growth factor insulin like growth factor 1 (IGF-1). Gut microbiota are capable of dynamically modulating circulating IGF-1 in the host, with the majority of data suggesting that microbiota induce host IGF-1 synthesis to influence growth. Microbiota-derived metabolites such as short chain fatty acids are sufficient to induce IGF-1. Whether microbiota induction of IGF-1 is mediated by the difference in growth hormone expression or the host sensitivity to growth hormone is still under investigation. This review summarizes the current data detailing the interaction between gut microbiota, IGF-1 and host development.

Can the behaviour of threespine stickleback parasitized with Schistocephalus solidus be replicated by manipulating host physiology?

PubMed

Grécias, Lucie; Hébert, François Olivier; Berger, Chloé Suzanne; Barber, Iain; Aubin-Horth, Nadia

2017-01-15

Sticklebacks infected by the parasitic flatworm Schistocephalus solidus show dramatic changes in phenotype, including a loss of species-typical behavioural responses to predators. The timing of host behaviour change coincides with the development of infectivity of the parasite to the final host (a piscivorous bird), making it an ideal model for studying the mechanisms of infection-induced behavioural modification. However, whether the loss of host anti-predator behaviour results from direct manipulation by the parasite, or is a by-product (e.g. host immune response) or side effect of infection (e.g. energetic loss), remains controversial. To understand the physiological mechanisms that generate these behavioural changes, we quantified the behavioural profiles of experimentally infected fish and attempted to replicate these in non-parasitized fish by exposing them to treatments including immunity activation and fasting, or by pharmacologically inhibiting the stress axis. All fish were screened for the following behaviours: activity, water depth preference, sociability, phototaxis, anti-predator response and latency to feed. We were able to change individual behaviours with certain treatments. Our results suggest that the impact of S. solidus on the stickleback might be of a multifactorial nature. The behaviour changes observed in infected fish might result from the combined effects of modifying the serotonergic axis, lack of energy and activation of the immune system. © 2017. Published by The Company of Biologists Ltd.

Physiological and biochemical performances of menthol-induced aposymbiotic corals.

PubMed

Wang, Jih-Terng; Chen, Yi-Yun; Tew, Kwee Siong; Meng, Pei-Jei; Chen, Chaolun A

2012-01-01

The unique mutualism between corals and their photosynthetic zooxanthellae (Symbiodinium spp.) is the driving force behind functional assemblages of coral reefs. However, the respective roles of hosts and Symbiodinium in this endosymbiotic association, particularly in response to environmental challenges (e.g., high sea surface temperatures), remain unsettled. One of the key obstacles is to produce and maintain aposymbiotic coral hosts for experimental purposes. In this study, a simple and gentle protocol to generate aposymbiotic coral hosts (Isopora palifera and Stylophora pistillata) was developed using repeated incubation in menthol/artificial seawater (ASW) medium under light and in ASW in darkness, which depleted more than 99% of Symbiodinium from the host within 4∼8 days. As indicated by the respiration rate, energy metabolism (by malate dehydrogenase activity), and nitrogen metabolism (by glutamate dehydrogenase activity and profiles of free amino acids), the physiological and biochemical performances of the menthol-induced aposymbiotic corals were comparable to their symbiotic counterparts without nutrient supplementation (e.g., for Stylophora) or with a nutrient supplement containing glycerol, vitamins, and a host mimic of free amino acid mixture (e.g., for Isopora). Differences in biochemical responses to menthol-induced bleaching between Stylophora and Isopora were attributed to the former digesting Symbiodinium rather than expelling the algae live as found in the latter species. Our studies showed that menthol could successfully bleach corals and provided aposymbiotic corals for further exploration of coral-alga symbioses.

Host-microbiota interactions: Epigenomic regulation

PubMed Central

Woo, Vivienne; Alenghat, Theresa

2016-01-01

The coevolution of mammalian hosts and their commensal microbiota has led to the development of complex symbiotic relationships between resident microbes and mammalian cells. Epigenomic modifications enable host cells to alter gene expression without modifying the genetic code, and therefore represent potent mechanisms by which mammalian cells can transcriptionally respond, transiently or stably, to environmental cues. Advances in genome-wide approaches are accelerating our appreciation of microbial influences on host physiology, and increasing evidence highlights that epigenomics represent a level of regulation by which the host integrates and responds to microbial signals. In particular, bacterial-derived short chain fatty acids have emerged as one clear link between how the microbiota intersects with host epigenomic pathways. Here we review recent findings describing crosstalk between the microbiota and epigenomic pathways in multiple mammalian cell populations. Further, we discuss interesting links that suggest that the scope of our understanding of epigenomic regulation in the host-microbiota relationship is still in its infancy. PMID:28103497

Inflammation in aging part 1: physiology and immunological mechanisms.

PubMed

Hunt, Katherine J; Walsh, Bronagh M; Voegeli, David; Roberts, Helen C

2010-01-01

During the aging process, remodeling of several body systems occurs, and these changes can have a startling effect upon the immune system. The reduction in sex steroids and growth hormones and declines in vitamin D concentration that accompany the aging process are associated with increases in the baseline levels of inflammatory proteins. At the same time, inflammation arising from atherosclerosis and other chronic diseases further contributes to the inflammatory milieu and effects a state of chronic inflammation. This chronic inflammation, or ''inflammaging'' as it has been termed, seems to be associated with a host of adverse effects contributing to many of the health problems that increase morbidity and decrease both quality of life and the ability to maintain independence in old age. For nurses to be truly informed when caring for older people and to ensure that they have a detailed understanding of the complexities of older people's health needs, they must have a knowledge of the physiological and immunological changes with age. This is the first of a two-part article on inflammatory processes in aging. These age-related changes are presented here, including an examination of the impact of genetic and lifestyle factors. The effect of these changes on the health of the individual and implications for practice are described in Part 2.

Metabolic interdependence of obligate intracellular bacteria and their insect hosts.

PubMed

Zientz, Evelyn; Dandekar, Thomas; Gross, Roy

2004-12-01

Mutualistic associations of obligate intracellular bacteria and insects have attracted much interest in the past few years due to the evolutionary consequences for their genome structure. However, much less attention has been paid to the metabolic ramifications for these endosymbiotic microorganisms, which have to compete with but also to adapt to another metabolism--that of the host cell. This review attempts to provide insights into the complex physiological interactions and the evolution of metabolic pathways of several mutualistic bacteria of aphids, ants, and tsetse flies and their insect hosts.

Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont, Desulfobulbus oralis

DOE PAGES

Cross, Karissa L.; Chirania, Payal; Xiong, Weili; ...

2018-03-13

The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously unculturedDesulfobulbus oralis , the first human-associated representative of its genus. As mammalian-associated microbes rarely have free-living close relatives,D. oralis provides opportunities to study how bacteria adapt and evolve within a host. This sulfate-reducing deltaproteobacterium has adapted to the human oral subgingival niche by curtailing its physiological repertoire, losing some biosynthetic abilities and metabolic independence, and by dramatically reducing environmental sensing and signaling capabilities. The genes that enable free-living Desulfobulbus to synthesize the potent neurotoxin methylmercury weremore » also lost byD. oralis, a notably positive outcome of host association. However, horizontal gene acquisitions from other members of the microbiota provided novel mechanisms of interaction with the human host, including toxins like leukotoxin and hemolysins. Proteomic and transcriptomic analysis revealed that most of those factors are actively expressed, including in the subgingival environment, and some are secreted. Similar to other known oral pathobionts, D. oralis can trigger a proinflammatory response in oral epithelial cells, suggesting a direct role in the development of periodontal disease. Animal-associated microbiota likely assembled as a result of numerous independent colonization events by free-living microbes followed by coevolution with their host and other microbes. Through specific adaptation to various body sites and physiological niches, microbes have a wide range of contributions, from beneficial to disease causing.Desulfobulbus oralis provides insights into genomic and physiological transformations associated with transition from an open environment to a host-dependent lifestyle and the emergence of pathogenicity. Through a multifaceted mechanism triggering a proinflammatory response, D. oralis is a novel periodontal pathobiont. Even though culture-independent approaches can provide insights into the potential role of the human microbiome “dark matter,” cultivation and experimental characterization remain important to studying the roles of individual organisms in health and disease.« less

Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont, Desulfobulbus oralis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cross, Karissa L.; Chirania, Payal; Xiong, Weili

The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously unculturedDesulfobulbus oralis , the first human-associated representative of its genus. As mammalian-associated microbes rarely have free-living close relatives,D. oralis provides opportunities to study how bacteria adapt and evolve within a host. This sulfate-reducing deltaproteobacterium has adapted to the human oral subgingival niche by curtailing its physiological repertoire, losing some biosynthetic abilities and metabolic independence, and by dramatically reducing environmental sensing and signaling capabilities. The genes that enable free-living Desulfobulbus to synthesize the potent neurotoxin methylmercury weremore » also lost byD. oralis, a notably positive outcome of host association. However, horizontal gene acquisitions from other members of the microbiota provided novel mechanisms of interaction with the human host, including toxins like leukotoxin and hemolysins. Proteomic and transcriptomic analysis revealed that most of those factors are actively expressed, including in the subgingival environment, and some are secreted. Similar to other known oral pathobionts, D. oralis can trigger a proinflammatory response in oral epithelial cells, suggesting a direct role in the development of periodontal disease. Animal-associated microbiota likely assembled as a result of numerous independent colonization events by free-living microbes followed by coevolution with their host and other microbes. Through specific adaptation to various body sites and physiological niches, microbes have a wide range of contributions, from beneficial to disease causing.Desulfobulbus oralis provides insights into genomic and physiological transformations associated with transition from an open environment to a host-dependent lifestyle and the emergence of pathogenicity. Through a multifaceted mechanism triggering a proinflammatory response, D. oralis is a novel periodontal pathobiont. Even though culture-independent approaches can provide insights into the potential role of the human microbiome “dark matter,” cultivation and experimental characterization remain important to studying the roles of individual organisms in health and disease.« less

Biomarkers: d13C and d15N Distribution Tightly Coupled to Nutrient Dynamics and Viral Lysing in a Microbial Mat From Death Valley, California

NASA Astrophysics Data System (ADS)

Hewson, I.; Archer, R.; Mahaffey, C.; Scott, J.; Tsapin, A.

2002-12-01

Extrapolations into ancient biomes make many assumptions and inferences regarding life modes and environmental habitat. While definition of a stromatolite as an extinct microbial biome by petrographic analysis is promising, Life interacts with is environment, actively manipulating energy flow across chemical disequilibria gradients, harvesting energy crucial for physiological maintenance and reproduction. Such structuring of communities in turn, leaves specific chemical/isotopic imprints related to physiological processes of prokaryotic communities specific to each oxidation/redox horizon. We examine stable isotopic d13C signals (d13C and d15N) as potential biomarkers reflecting bacterial physiology and microbial community nutrient-energy dynamics. While isotopes may reveal ancient chemical structuring of microbial mats, we also turn to invoking viral lysing of bacterial hosts in nutrient cycling within modern extreme environments as well as ancient stromatic structures of early Earth. Our records of d13C indicate extreme enrichment(-12%) for Corg in our extant mat due to CO2 limitation across a hypersaline diffusive barrier at the mat's surface. d15N is lowest at the mat's surface (indicating N2- fixation) where nitrogen- fixing cyanobacteria Microcoleus sp. are present . Viruses are extremely abundant in the microbial mat, exceeding bacterial abundances by a factor of ten. The ratio of viruses to bacteria was very high (VBR = 39 ñ 10) compared with abundances in marine sediments. Distribution of viruses closely follows distribution of bacteria, suggesting bacteria as primary hosts. The ratio of viruses to bacteria is inversely correlated to the concentration of organic C suggesting virus abundance is responsive to host substrate availability. High ratios of viruses to bacteria in mid-mat horizons (2.5 - 3.7 cm) above increasing levels of d13C in deeper horizons, coupled with a lack of increase in bacteria, suggests that viral lysis contributes to significant downward organic C (polysaccaride exudates) transport within the mat. Subsequent accumulation of d13C as well as heavier d15N in deeper sediment(denitrification)horizons elucidates tight nutrient coupling between evaporite substrate, nitrogen fixing primary producers and downcore zones of active denitrification and sulphate reduction. Discrepencies between d13C of ancient stromatolites (in line with C-3 photosynthetic pathways) and modern analogues (Badwater, CA) suggest a migration of microbial mats towards more extreme environments through time. A methodology for isotopically testing environmental and physiological responses in the geological record is presented here.

The response to unfolded protein is involved in osmotolerance of Pichia pastoris

PubMed Central

2010-01-01

Background The effect of osmolarity on cellular physiology has been subject of investigation in many different species. High osmolarity is of importance for biotechnological production processes, where high cell densities and product titers are aspired. Several studies indicated that increased osmolarity of the growth medium can have a beneficial effect on recombinant protein production in different host organisms. Thus, the effect of osmolarity on the cellular physiology of Pichia pastoris, a prominent host for recombinant protein production, was studied in carbon limited chemostat cultures at different osmolarities. Transcriptome and proteome analyses were applied to assess differences upon growth at different osmolarities in both, a wild type strain and an antibody fragment expressing strain. While our main intention was to analyze the effect of different osmolarities on P. pastoris in general, this was complemented by studying it in context with recombinant protein production. Results In contrast to the model yeast Saccharomyces cerevisiae, the main osmolyte in P. pastoris was arabitol rather than glycerol, demonstrating differences in osmotic stress response as well as energy metabolism. 2D Fluorescence Difference Gel electrophoresis and microarray analysis were applied and demonstrated that processes such as protein folding, ribosome biogenesis and cell wall organization were affected by increased osmolarity. These data indicated that upon increased osmolarity less adaptations on both the transcript and protein level occurred in a P. pastoris strain, secreting the Fab fragment, compared with the wild type strain. No transcriptional activation of the high osmolarity glycerol (HOG) pathway was observed at steady state conditions. Furthermore, no change of the specific productivity of recombinant Fab was observed at increased osmolarity. Conclusion These data point out that the physiological response to increased osmolarity is different to S. cerevisiae. Increased osmolarity resulted in an unfolded protein response (UPR) like response in P. pastoris and lead to pre-conditioning of the recombinant Fab producing strain of P. pastoris to growth at high osmolarity. The current data demonstrate a strong similarity of environmental stress response mechanisms and recombinant protein related stresses. Therefore, these results might be used in future strain and bioprocess engineering of this biotechnologically relevant yeast. PMID:20346137

Structural basis for host membrane remodeling induced by protein 2B of hepatitis A virus.

PubMed

Vives-Adrián, Laia; Garriga, Damià; Buxaderas, Mònica; Fraga, Joana; Pereira, Pedro José Barbosa; Macedo-Ribeiro, Sandra; Verdaguer, Núria

2015-04-01

The complexity of viral RNA synthesis and the numerous participating factors require a mechanism to topologically coordinate and concentrate these multiple viral and cellular components, ensuring a concerted function. Similarly to all other positive-strand RNA viruses, picornaviruses induce rearrangements of host intracellular membranes to create structures that act as functional scaffolds for genome replication. The membrane-targeting proteins 2B and 2C, their precursor 2BC, and protein 3A appear to be primarily involved in membrane remodeling. Little is known about the structure of these proteins and the mechanisms by which they induce massive membrane remodeling. Here we report the crystal structure of the soluble region of hepatitis A virus (HAV) protein 2B, consisting of two domains: a C-terminal helical bundle preceded by an N-terminally curved five-stranded antiparallel β-sheet that displays striking structural similarity to the β-barrel domain of enteroviral 2A proteins. Moreover, the helicoidal arrangement of the protein molecules in the crystal provides a model for 2B-induced host membrane remodeling during HAV infection. No structural information is currently available for the 2B protein of any picornavirus despite it being involved in a critical process in viral factory formation: the rearrangement of host intracellular membranes. Here we present the structure of the soluble domain of the 2B protein of hepatitis A virus (HAV). Its arrangement, both in crystals and in solution under physiological conditions, can help to understand its function and sheds some light on the membrane rearrangement process, a putative target of future antiviral drugs. Moreover, this first structure of a picornaviral 2B protein also unveils a closer evolutionary relationship between the hepatovirus and enterovirus genera within the Picornaviridae family. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Structural Basis for Host Membrane Remodeling Induced by Protein 2B of Hepatitis A Virus

PubMed Central

Vives-Adrián, Laia; Garriga, Damià; Buxaderas, Mònica; Fraga, Joana; Pereira, Pedro José Barbosa

2015-01-01

ABSTRACT The complexity of viral RNA synthesis and the numerous participating factors require a mechanism to topologically coordinate and concentrate these multiple viral and cellular components, ensuring a concerted function. Similarly to all other positive-strand RNA viruses, picornaviruses induce rearrangements of host intracellular membranes to create structures that act as functional scaffolds for genome replication. The membrane-targeting proteins 2B and 2C, their precursor 2BC, and protein 3A appear to be primarily involved in membrane remodeling. Little is known about the structure of these proteins and the mechanisms by which they induce massive membrane remodeling. Here we report the crystal structure of the soluble region of hepatitis A virus (HAV) protein 2B, consisting of two domains: a C-terminal helical bundle preceded by an N-terminally curved five-stranded antiparallel β-sheet that displays striking structural similarity to the β-barrel domain of enteroviral 2A proteins. Moreover, the helicoidal arrangement of the protein molecules in the crystal provides a model for 2B-induced host membrane remodeling during HAV infection. IMPORTANCE No structural information is currently available for the 2B protein of any picornavirus despite it being involved in a critical process in viral factory formation: the rearrangement of host intracellular membranes. Here we present the structure of the soluble domain of the 2B protein of hepatitis A virus (HAV). Its arrangement, both in crystals and in solution under physiological conditions, can help to understand its function and sheds some light on the membrane rearrangement process, a putative target of future antiviral drugs. Moreover, this first structure of a picornaviral 2B protein also unveils a closer evolutionary relationship between the hepatovirus and enterovirus genera within the Picornaviridae family. PMID:25589659

Development of wireless brain computer interface with embedded multitask scheduling and its application on real-time driver's drowsiness detection and warning.

PubMed

Lin, Chin-Teng; Chen, Yu-Chieh; Huang, Teng-Yi; Chiu, Tien-Ting; Ko, Li-Wei; Liang, Sheng-Fu; Hsieh, Hung-Yi; Hsu, Shang-Hwa; Duann, Jeng-Ren

2008-05-01

Biomedical signal monitoring systems have been rapidly advanced with electronic and information technologies in recent years. However, most of the existing physiological signal monitoring systems can only record the signals without the capability of automatic analysis. In this paper, we proposed a novel brain-computer interface (BCI) system that can acquire and analyze electroencephalogram (EEG) signals in real-time to monitor human physiological as well as cognitive states, and, in turn, provide warning signals to the users when needed. The BCI system consists of a four-channel biosignal acquisition/amplification module, a wireless transmission module, a dual-core signal processing unit, and a host system for display and storage. The embedded dual-core processing system with multitask scheduling capability was proposed to acquire and process the input EEG signals in real time. In addition, the wireless transmission module, which eliminates the inconvenience of wiring, can be switched between radio frequency (RF) and Bluetooth according to the transmission distance. Finally, the real-time EEG-based drowsiness monitoring and warning algorithms were implemented and integrated into the system to close the loop of the BCI system. The practical online testing demonstrates the feasibility of using the proposed system with the ability of real-time processing, automatic analysis, and online warning feedback in real-world operation and living environments.

Circadian egg production by Echinostoma caproni (Digenea: Echinostomatidae) in ICR mice.

PubMed

Platt, Thomas R; Hussey, Gabrielle L; Zelmer, Derek A

2013-04-01

Circadian egg production by Echinostoma caproni was investigated in ICR mice. Four female mice were infected with 25 E. caproni metacercariae, maintained in individual cages on a 12:12 light:dark cycle, and provided food and water ad libitum. Twenty-eight, 51, and 58 days post-infection, mice were transferred to individual, wire-bottomed cages and feces were collected every 2 hr for 24 hr. The feces were weighed and processed immediately to estimate the number of eggs present. Fecal output and egg production were standardized to unit maxima for analysis. Standardized egg count and standardized fecal output followed distinctly circadian patterns and covaried. Egg production was highest from 2200 to 0200 hr and lowest from 1000 to 1800 hr. These correspond to the highest and lowest fecal production, and highest and lowest periods of host activity, respectively. Egg density (eggs/g of feces) covaried weakly with fecal output with an additional peak at 0800-1000 hr, suggesting E. caproni is responding to changes in host physiology in timing of the production and release of eggs into the intestine. The continuous production and release of eggs during the patent period, coupled with the circadian pattern of daily egg release by E. caproni , would result in the widest dispersal of eggs in the host environment and enhance transmission to the first intermediate host.

Segment-specific responses of intestinal epithelium transcriptome to in-feed antibiotics in pigs.

PubMed

Yu, Kaifan; Mu, Chunlong; Yang, Yuxiang; Su, Yong; Zhu, Weiyun

2017-10-01

Despite widespread use of antibiotics for treatment of human diseases and promotion of growth of agricultural animals, our understanding of their effects on the host is still very limited. We used a model in which pigs were fed with or without a cocktail of antibiotics and found, based on the denaturing gradient gel electrophoresis (DGGE) patterns, that the fecal bacteria from the treatment and control animals were distinct. Furthermore, the total bacterial population in the feces tended to be decreased by the antibiotic treatment ( P = 0.07), and the counts of Lactobacillus and Clostridium XIVa were significantly reduced ( P < 0.05). To explore the effects of antibiotics on host intestinal epithelium, we assessed gene expression profiles of the jejunum and ileum and their response to antibiotic administration. The results indicate that in-feed antibiotics increased expression of genes involved in immune functions in both the jejunum and ileum, some of which were clustered in the coexpression network. Gene ontology terms of metabolic processes were altered predominantly in the jejunum but not in the ileum. Notably, antibiotics diminished intestinal segment-specific transcriptional changes, especially for genes associated with metabolic functions. This study reveals segment-specific responses of host intestinal epithelium to in-feed antibiotics, which can be a valuable resource for deciphering antibiotic-microbiota-host interactions. Copyright © 2017 the American Physiological Society.

Partial venom gland transcriptome of a Drosophila parasitoid wasp, Leptopilina heterotoma, reveals novel and shared bioactive profiles with stinging Hymenoptera

PubMed Central

Heavner, Mary E.; Gueguen, Gwenaelle; Rajwani, Roma; Pagan, Pedro E.; Small, Chiyedza; Govind, Shubha

2013-01-01

Analysis of natural host-parasite relationships reveals the evolutionary forces that shape the delicate and unique specificity characteristic of such interactions. The accessory long gland-reservoir complex of the wasp Leptopilina heterotoma (Figitidae) produces venom with virus-like particles. Upon delivery, venom components delay host larval development and completely block host immune responses. The host range of this Drosophila endoparasitoid notably includes the highly-studied model organism, Drosophila melanogaster. Categorization of 827 unigenes, using similarity as an indicator of putative homology, reveals that approximately 25% are novel or classified as hypothetical proteins. Most of the remaining unigenes are related to processes involved in signaling, cell cycle, and cell physiology including detoxification, protein biogenesis, and hormone production. Analysis of L. heterotoma’s predicted venom gland proteins demonstrates conservation among endo- and ectoparasitoids within the Apocrita (e.g., this wasp and the jewel wasp Nasonia vitripennis) and stinging aculeates (e.g., the honey bee and ants). Enzyme and KEGG pathway profiling predicts that kinases, esterases, and hydrolases may contribute to venom activity in this unique wasp. To our knowledge, this investigation marks the first functional genomic study for a natural parasitic wasp of Drosophila. Our findings will help explain how L. heterotoma shuts down its hosts’ immunity and shed light on the molecular basis of a natural arms race between these insects. PMID:23688557

Explaining variance of avian malaria infection in the wild: the importance of host density, habitat, individual life-history and oxidative stress.

PubMed

Isaksson, Caroline; Sepil, Irem; Baramidze, Vladimer; Sheldon, Ben C

2013-04-08

Avian malaria (Plasmodium sp.) is globally widespread, but considerable variation exists in infection (presence/absence) patterns at small spatial scales. This variation can be driven by variation in ecology, demography, and phenotypic characters, in particular those that influence the host's resistance. Generation of reactive oxygen species (ROS) is one of the host's initial immune responses to combat parasitic invasion. However, long-term ROS exposure can harm the host and the redox response therefore needs to be adjusted according to infection stage and host phenotype. Here we use experimental and correlational approaches to assess the relative importance of host density, habitat composition, individual level variation and redox physiology for Plasmodium infection in a wild population of great tits, Parus major. We found that 36% of the great tit population was infected with Plasmodium (22% P. relictum and 15% P. circumflexum prevalence) and that patterns of infection were Plasmodium species-specific. First, the infection of P. circumflexum was significantly higher in areas with experimental increased host density, whereas variation in P. relictum infection was mainly attributed to age, sex and reproduction. Second, great tit antioxidant responses - total and oxidizied glutathione - showed age- , sex- and Plasmodium species-specific patterns between infected and uninfected individuals, but reactive oxygen metabolites (ROM) showed only a weak explanatory power for patterns of P. relictum infection. Instead ROM significantly increased with Plasmodium parasitaemia. These results identify some key factors that influence Plasmodium infection in wild birds, and provide a potential explanation for the underlying physiological basis of recently documented negative effects of chronic avian malaria on survival and reproductive success.

Intervention strategies for cesarean section-induced alterations in the microbiota-gut-brain axis.

PubMed

Moya-Pérez, Angela; Luczynski, Pauline; Renes, Ingrid B; Wang, Shugui; Borre, Yuliya; Anthony Ryan, C; Knol, Jan; Stanton, Catherine; Dinan, Timothy G; Cryan, John F

2017-04-01

Microbial colonization of the gastrointestinal tract is an essential process that modulates host physiology and immunity. Recently, researchers have begun to understand how and when these microorganisms colonize the gut and the early-life factors that impact their natural ecological establishment. The vertical transmission of maternal microbes to the offspring is a critical factor for host immune and metabolic development. Increasing evidence also points to a role in the wiring of the gut-brain axis. This process may be altered by various factors such as mode of delivery, gestational age at birth, the use of antibiotics in early life, infant feeding, and hygiene practices. In fact, these early exposures that impact the intestinal microbiota have been associated with the development of diseases such as obesity, type 1 diabetes, asthma, allergies, and even neurodevelopmental disorders. The present review summarizes the impact of cesarean birth on the gut microbiome and the health status of the developing infant and discusses possible preventative and restorative strategies to compensate for early-life microbial perturbations. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute.

Oleaginous yeasts: Promising platforms for the production of oleochemicals and biofuels.

PubMed

Adrio, José L

2017-09-01

Oleaginous yeasts have a unique physiology that makes them the best suited hosts for the production of lipids, oleochemicals, and diesel-like fuels. Their high lipogenesis, capability of growing on many different carbon sources (including lignocellulosic sugars), easy large-scale cultivation, and an increasing number of genetic tools are some of the advantages that have encouraged their use to develop sustainable processes. This mini-review summarizes the metabolic engineering strategies developed in oleaginous yeasts within the last 2 years to improve process metrics (titer, yield, and productivity) for the production of lipids, free fatty acids, fatty acid-based chemicals (e.g., fatty alcohols, fatty acid ethyl esters), and alkanes. During this short period of time, tremendous progress has been made in Yarrowia lipolytica, the model oleaginous yeast, which has been engineered to improve lipid production by different strategies including increasing lipogenic pathway flux and biosynthetic precursors, and blocking degradation pathways. Moreover, remarkable advances have also been reported in Rhodosporidium toruloides and Lipomyces starkey despite the limited genetic tools available for these two very promising hosts. Biotechnol. Bioeng. 2017;114: 1915-1920. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Expanding the universe of cytokines and pattern recognition receptors: galectins and glycans in innate immunity.

PubMed

Cerliani, Juan P; Stowell, Sean R; Mascanfroni, Iván D; Arthur, Connie M; Cummings, Richard D; Rabinovich, Gabriel A

2011-02-01

Effective immunity relies on the recognition of pathogens and tumors by innate immune cells through diverse pattern recognition receptors (PRRs) that lead to initiation of signaling processes and secretion of pro- and anti-inflammatory cytokines. Galectins, a family of endogenous lectins widely expressed in infected and neoplastic tissues have emerged as part of the portfolio of soluble mediators and pattern recognition receptors responsible for eliciting and controlling innate immunity. These highly conserved glycan-binding proteins can control immune cell processes through binding to specific glycan structures on pathogens and tumors or by acting intracellularly via modulation of selective signaling pathways. Recent findings demonstrate that various galectin family members influence the fate and physiology of different innate immune cells including polymorphonuclear neutrophils, mast cells, macrophages, and dendritic cells. Moreover, several pathogens may actually utilize galectins as a mechanism of host invasion. In this review, we aim to highlight and integrate recent discoveries that have led to our current understanding of the role of galectins in host-pathogen interactions and innate immunity. Challenges for the future will embrace the rational manipulation of galectin-glycan interactions to instruct and shape innate immunity during microbial infections, inflammation, and cancer.

Mistletoe infection alters the transpiration flow path and suppresses water regulation of host trees during extreme events

NASA Astrophysics Data System (ADS)

Griebel, A.; Maier, C.; Barton, C. V.; Metzen, D.; Renchon, A.; Boer, M. M.; Pendall, E.

2017-12-01

Mistletoe is a globally distributed group of parasitic plants that infiltrates the vascular tissue of its host trees to acquire water, carbon and nutrients, making it a leading agent of biotic disturbance. Many mistletoes occur in water-limited ecosystems, thus mistletoe infection in combination with increased climatic stress may exacerbate water stress and potentially accelerate mortality rates of infected trees during extreme events. This is an emerging problem in Australia, as mistletoe distribution is increasing and clear links between mistletoe infection and mortality have been established. However, direct observations about how mistletoes alter host physiological processes during extreme events are rare, which impedes our understanding of mechanisms underlying increased tree mortality rates. We addressed this gap by continuously monitoring stem and branch sap flow and a range of leaf traits of infected and uninfected trees of two co-occurring eucalypt species during a severe heatwave in south-eastern Australia. We demonstrate that mistletoes' leaf water potentials were maintained 30% lower than hosts' to redirect the trees' transpiration flow path towards mistletoe leaves. Eucalypt leaves reduced water loss through stomatal regulation when atmospheric dryness exceeded 2 kPa, but the magnitude of stomatal regulation in non-infected eucalypts differed by species (between 40-80%). Remarkably, when infected, sap flow rates of stems and branches of both eucalypt species remained unregulated even under extreme atmospheric dryness (>8 kPa). Our observations indicate that excessive water use of mistletoes likely increases xylem cavitation rates in hosts during prolonged droughts and supports that hydraulic failure contributes to increased mortality of infected trees. Hence, in order to accurately model the contribution of biotic disturbances to tree mortality under a changing climate, it will be crucial to increase our process-based understanding of the interaction between biotic and abiotic dynamics, especially to establish thresholds of critical cavitation rates of infected trees.

Uptake and intra-inclusion accumulation of exogenous immunoglobulin by Chlamydia-infected cells

PubMed Central

Pollack, David V; Croteau, Nancy L; Stuart, Elizabeth S

2008-01-01

Background Obligate intracellular pathogens belonging to the Chlamydiaceae family possess a number of mechanisms by which to manipulate the host cell and surrounding environment. Such capabilities include the inhibition of apoptosis, down-regulation of major histocompatability complex (MHC) and CD1/d gene expression, and the acquisition of host-synthesized nutrients. It is also documented that a limited number of host-derived macromolecules such as β-catenin and sphingomyelin accumulate within the inclusion. Results This report provides evidence that immunoglobulin, inherently present in the extracellular environment in vivo and in vitro, enters infected cells and accumulates within the chlamydial inclusion. Using epi-fluorescent and confocal microscopy, this selective uptake of Ig is shown to occur among human leukocytes in vivo as well as cells cultured in vitro. These findings were confirmed by detection of IgG in the lysate of infected cells by western blot hybridization. Sequestered antibodies appear to be present during the entire course of the chlamydial developmental cycle and are distributed throughout this compartment. IgG pre-labeled with fluorescein, when added to the supernatant of infected cell cultures, was also imported and readily visualized. Accumulation of these molecules within the inclusion and the failure of bovine serum albumin or F(ab')2 fragments to accumulate in a similar manner suggests the process of entry is specific for intact IgG molecules and not a result of pinocytosis, diffusion, or any other mass endocytic event. Conclusion Sequestration of a host cell-derived protein within the chlamydial inclusion, although unexpected, is not an unprecedented occurrence. However, selective accumulation of an exogenous host protein, such as extracellular IgG, has not been previously reported in connection with chlamydial infections. The selectivity of this process may indicate that this uptake plays an important role in pathogen physiology or virulence during infection and the phenomenon itself may give rise to novel diagnostic and therapeutic approaches. PMID:19061499

Sleep in childhood and adolescence: age-specific sleep characteristics, common sleep disturbances and associated difficulties.

PubMed

Barclay, Nicola L; Gregory, Alice M

2014-01-01

Sleep changes throughout the lifespan, with particularly salient alterations occurring during the first few years of life, as well as during the transition from childhood to adolescence. Such changes are partly the result of brain maturation; complex changes in the organisation of the circadian system; as well as changes in daily routine, environmental demands and responsibilities. Despite the automaticity of sleep, given that it is governed by a host of complex mechanisms, there are times when sleep becomes disturbed. Sleep disturbances in childhood are common and may stem from behavioural difficulties or abnormalities in physiological processes-and, in some cases manifest into diagnosable sleep disorders. As well as occurring exclusively, childhood sleep disturbances often co-occur with other difficulties. The purpose of this chapter is to outline the neurobiology of typical sleep/wake processes, and describe changes in sleep physiology and architecture from birth to adulthood. Furthermore, common childhood sleep disorders are described as are their associations with other traits, including all of the syndromes presented in this handbook: ASDs, ADHD, schizophrenia and emotional/behavioural difficulties. Throughout, we attempt to explain possible mechanisms underlying these disorders and their associations.

The Chemistry of Plant–Microbe Interactions in the Rhizosphere and the Potential for Metabolomics to Reveal Signaling Related to Defense Priming and Induced Systemic Resistance

PubMed Central

Mhlongo, Msizi I.; Piater, Lizelle A.; Madala, Ntakadzeni E.; Labuschagne, Nico; Dubery, Ian A.

2018-01-01

Plant roots communicate with microbes in a sophisticated manner through chemical communication within the rhizosphere, thereby leading to biofilm formation of beneficial microbes and, in the case of plant growth-promoting rhizomicrobes/-bacteria (PGPR), resulting in priming of defense, or induced resistance in the plant host. The knowledge of plant–plant and plant–microbe interactions have been greatly extended over recent years; however, the chemical communication leading to priming is far from being well understood. Furthermore, linkage between below- and above-ground plant physiological processes adds to the complexity. In metabolomics studies, the main aim is to profile and annotate all exo- and endo-metabolites in a biological system that drive and participate in physiological processes. Recent advances in this field has enabled researchers to analyze 100s of compounds in one sample over a short time period. Here, from a metabolomics viewpoint, we review the interactions within the rhizosphere and subsequent above-ground ‘signalomics’, and emphasize the contributions that mass spectrometric-based metabolomic approaches can bring to the study of plant-beneficial – and priming events. PMID:29479360

Characterization of regulatory pathways in Xylella fastidiosa: genes and phenotypes controlled by gacA.

PubMed

Shi, Xiang Yang; Dumenyo, C Korsi; Hernandez-Martinez, Rufina; Azad, Hamid; Cooksey, Donald A

2009-04-01

The xylem-limited, insect-transmitted bacterium Xylella fastidiosa causes Pierce's disease in grapes through cell aggregation and vascular clogging. GacA controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in Pseudomonas syringae pv. tomato DC3000. Cloned gacA of X. fastidiosa was found to restore the hypersensitive response and pathogenicity in gacA mutants of P. syringae pv. tomato DC3000 and Erwinia amylovora. A gacA mutant of X. fastidiosa (DAC1984) had significantly reduced abilities to adhere to a glass surface, form biofilm, and incite disease symptoms on grapevines, compared with the parent (A05). cDNA microarray analysis identified 7 genes that were positively regulated by GacA, including xadA and hsf, predicted to encode outer membrane adhesion proteins, and 20 negatively regulated genes, including gumC and an antibacterial polypeptide toxin gene, cvaC. These results suggest that GacA of X. fastidiosa regulates many factors, which contribute to attachment and biofilm formation, as well as some physiological processes that may enhance the adaptation and tolerance of X. fastidiosa to environmental stresses and the competition within the host xylem.

Host-Brucella interactions and the Brucella genome as tools for subunit antigen discovery and immunization against brucellosis

PubMed Central

Gomez, Gabriel; Adams, Leslie G.; Rice-Ficht, Allison; Ficht, Thomas A.

2013-01-01

Vaccination is the most important approach to counteract infectious diseases. Thus, the development of new and improved vaccines for existing, emerging, and re-emerging diseases is an area of great interest to the scientific community and general public. Traditional approaches to subunit antigen discovery and vaccine development lack consideration for the critical aspects of public safety and activation of relevant protective host immunity. The availability of genomic sequences for pathogenic Brucella spp. and their hosts have led to development of systems-wide analytical tools that have provided a better understanding of host and pathogen physiology while also beginning to unravel the intricacies at the host-pathogen interface. Advances in pathogen biology, host immunology, and host-agent interactions have the potential to serve as a platform for the design and implementation of better-targeted antigen discovery approaches. With emphasis on Brucella spp., we probe the biological aspects of host and pathogen that merit consideration in the targeted design of subunit antigen discovery and vaccine development. PMID:23720712

Transcription Profiling of Bacillus subtilis Cells Infected with AR9, a Giant Phage Encoding Two Multisubunit RNA Polymerases.

PubMed

Lavysh, Daria; Sokolova, Maria; Slashcheva, Marina; Förstner, Konrad U; Severinov, Konstantin

2017-02-14

Bacteriophage AR9 is a recently sequenced jumbo phage that encodes two multisubunit RNA polymerases. Here we investigated the AR9 transcription strategy and the effect of AR9 infection on the transcription of its host, Bacillus subtilis Analysis of whole-genome transcription revealed early, late, and continuously expressed AR9 genes. Alignment of sequences upstream of the 5' ends of AR9 transcripts revealed consensus sequences that define early and late phage promoters. Continuously expressed AR9 genes have both early and late promoters in front of them. Early AR9 transcription is independent of protein synthesis and must be determined by virion RNA polymerase injected together with viral DNA. During infection, the overall amount of host mRNAs is significantly decreased. Analysis of relative amounts of host transcripts revealed notable differences in the levels of some mRNAs. The physiological significance of up- or downregulation of host genes for AR9 phage infection remains to be established. AR9 infection is significantly affected by rifampin, an inhibitor of host RNA polymerase transcription. The effect is likely caused by the antibiotic-induced killing of host cells, while phage genome transcription is solely performed by viral RNA polymerases. IMPORTANCE Phages regulate the timing of the expression of their own genes to coordinate processes in the infected cell and maximize the release of viral progeny. Phages also alter the levels of host transcripts. Here we present the results of a temporal analysis of the host and viral transcriptomes of Bacillus subtilis infected with a giant phage, AR9. We identify viral promoters recognized by two virus-encoded RNA polymerases that are a unique feature of the phiKZ-related group of phages to which AR9 belongs. Our results set the stage for future analyses of highly unusual RNA polymerases encoded by AR9 and other phiKZ-related phages. Copyright © 2017 Lavysh et al.

Alarmins and immunity.

PubMed

Yang, De; Han, Zhen; Oppenheim, Joost J

2017-11-01

More than a decade has passed since the conceptualization of the "alarmin" hypothesis. The alarmin family has been expanding in terms of both number and the concept. It has recently become clear that alarmins play important roles as initiators and participants in a diverse range of physiological and pathophysiological processes such as host defense, regulation of gene expression, cellular homeostasis, wound healing, inflammation, allergy, autoimmunity, and oncogenesis. Here, we provide a general view on the participation of alarmins in the induction of innate and adaptive immune responses, as well as their contribution to tumor immunity. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

PubMed

Pareja, Maria Eugenia Mansilla; Colombo, Maria I

2013-01-01

Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

Amblyomma americanum tick calreticulin binds C1q but does not inhibit activation of the classical complement cascade

PubMed Central

Kim, Tae Kwon; Ibelli, Adriana Mércia Guaratini; Mulenga, Albert

2014-01-01

In this study we characterized Amblyomma americanum (Aam) tick calreticulin (CRT) homolog in tick feeding physiology. In nature, different tick species can be found feeding on the same animal host. This suggests that different tick species found feeding on the same host can modulate the same host anti-tick defense pathways to successfully feed. From this perspective it’s plausible that different tick species can utilize universally conserved proteins such as CRT to regulate and facilitate feeding. CRT is a multi-functional protein found in most taxa that is injected into the vertebrate host during tick feeding. Apart from it’s current use as a biomarker for human tick bites, role(s) of this protein in tick feeding physiology have not been elucidated. Here we show that annotated functional CRT amino acid motifs are well conserved in tick CRT. However our data show that despite high amino acid identity levels to functionally characterized CRT homologs in other organisms, AamCRT is apparently functionally different. Pichia pastoris expressed recombinant (r) AamCRT bound C1q, the first component of the classical complement system, but it did not inhibit activation of this pathway. This contrast with reports of other parasite CRT that inhibited activation of the classical complement pathway through sequestration of C1q. Furthermore rAamCRT did not bind factor Xa in contrast to reports of parasite CRT binding factor Xa, an important protease in the blood clotting system. Consistent with this observation, rAamCRT did not affect plasma clotting or platelet aggregation aggregation. We discuss our findings in the context of tick feeding physiology. PMID:25454607

Filopodia and Viruses: An Analysis of Membrane Processes in Entry Mechanisms

PubMed Central

Chang, Kenneth; Baginski, John; Hassan, Samer F.; Volin, Michael; Shukla, Deepak; Tiwari, Vaibhav

2016-01-01

Filopodia are thin, actin rich bundles protruding from cell plasma membranes, serving physiological purposes, such as probing the environment and facilitating cell-to-cell adhesion. Recent studies have highlighted that actively polymerized filopodial-protrusions are exploited during virus entry, trafficking, spread, and the development of clinical pathology of viral diseases. These observations have caused a surge in investigation of the key determinants of filopodial induction and their influence on cell topography including receptor expression for viral entry. It is now very clear that filopodia can provide unique opportunities for many viruses to invade host cells vertically during primary infection, or horizontally during virus spread from cell-to-cell. These emerging concepts can explain the unprecedented ability of viruses to invade both nearby and long-distant host cells, a feature that may directly contribute to viral tropism. In this review, we summarize the significance of filopodia in viral diseases and discuss future therapeutic possibilities to precisely target filopodial-flyovers to prevent or control infectious diseases. PMID:27014223

Smart Parasitic Nematodes Use Multifaceted Strategies to Parasitize Plants

PubMed Central

Ali, Muhammad A.; Azeem, Farrukh; Li, Hongjie; Bohlmann, Holger

2017-01-01

Nematodes are omnipresent in nature including many species which are parasitic to plants and cause enormous economic losses in various crops. During the process of parasitism, sedentary phytonematodes use their stylet to secrete effector proteins into the plant cells to induce the development of specialized feeding structures. These effectors are used by the nematodes to develop compatible interactions with plants, partly by mimicking the expression of host genes. Intensive research is going on to investigate the molecular function of these effector proteins in the plants. In this review, we have summarized which physiological and molecular changes occur when endoparasitic nematodes invade the plant roots and how they develop a successful interaction with plants using the effector proteins. We have also mentioned the host genes which are induced by the nematodes for a compatible interaction. Additionally, we discuss how nematodes modulate the reactive oxygen species (ROS) and RNA silencing pathways in addition to post-translational modifications in their own favor for successful parasitism in plants. PMID:29046680

Animal Models for Periodontal Disease

PubMed Central

Oz, Helieh S.; Puleo, David A.

2011-01-01

Animal models and cell cultures have contributed new knowledge in biological sciences, including periodontology. Although cultured cells can be used to study physiological processes that occur during the pathogenesis of periodontitis, the complex host response fundamentally responsible for this disease cannot be reproduced in vitro. Among the animal kingdom, rodents, rabbits, pigs, dogs, and nonhuman primates have been used to model human periodontitis, each with advantages and disadvantages. Periodontitis commonly has been induced by placing a bacterial plaque retentive ligature in the gingival sulcus around the molar teeth. In addition, alveolar bone loss has been induced by inoculation or injection of human oral bacteria (e.g., Porphyromonas gingivalis) in different animal models. While animal models have provided a wide range of important data, it is sometimes difficult to determine whether the findings are applicable to humans. In addition, variability in host responses to bacterial infection among individuals contributes significantly to the expression of periodontal diseases. A practical and highly reproducible model that truly mimics the natural pathogenesis of human periodontal disease has yet to be developed. PMID:21331345

Smart Parasitic Nematodes Use Multifaceted Strategies to Parasitize Plants.

PubMed

Ali, Muhammad A; Azeem, Farrukh; Li, Hongjie; Bohlmann, Holger

2017-01-01

Nematodes are omnipresent in nature including many species which are parasitic to plants and cause enormous economic losses in various crops. During the process of parasitism, sedentary phytonematodes use their stylet to secrete effector proteins into the plant cells to induce the development of specialized feeding structures. These effectors are used by the nematodes to develop compatible interactions with plants, partly by mimicking the expression of host genes. Intensive research is going on to investigate the molecular function of these effector proteins in the plants. In this review, we have summarized which physiological and molecular changes occur when endoparasitic nematodes invade the plant roots and how they develop a successful interaction with plants using the effector proteins. We have also mentioned the host genes which are induced by the nematodes for a compatible interaction. Additionally, we discuss how nematodes modulate the reactive oxygen species (ROS) and RNA silencing pathways in addition to post-translational modifications in their own favor for successful parasitism in plants.

The Ebola virus glycoprotein mediates entry via a non-classical dynamin-dependent macropinocytic pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulherkar, Nirupama; Raaben, Matthijs; Torre, Juan Carlos de la

2011-10-25

Ebola virus (EBOV) has been reported to enter cultured cell lines via a dynamin-2-independent macropinocytic pathway or clathrin-mediated endocytosis. The route(s) of productive EBOV internalization into physiologically relevant cell types remain unexplored, and viral-host requirements for this process are incompletely understood. Here, we use electron microscopy and complementary chemical and genetic approaches to demonstrate that the viral glycoprotein, GP, induces macropinocytic uptake of viral particles into cells. GP's highly-glycosylated mucin domain is dispensable for virus-induced macropinocytosis, arguing that interactions between other sequences in GP and the host cell surface are responsible. Unexpectedly, we also found a requirement for the largemore » GTPase dynamin-2, which is proposed to be dispensable for several types of macropinocytosis. Our results provide evidence that EBOV uses an atypical dynamin-dependent macropinocytosis-like entry pathway to enter Vero cells, adherent human peripheral blood-derived monocytes, and a mouse dendritic cell line.« less

Is the Gut Microbiota a New Factor Contributing to Obesity and Its Metabolic Disorders?

PubMed Central

Harris, Kristina; Kassis, Amira; Major, Geneviève; Chou, Chieh J.

2012-01-01

The gut microbiota refers to the trillions of microorganisms residing in the intestine and is integral in multiple physiological processes of the host. Recent research has shown that gut bacteria play a role in metabolic disorders such as obesity, diabetes, and cardiovascular diseases. The mechanisms by which the gut microbiota affects metabolic diseases are by two major routes: (1) the innate immune response to the structural components of bacteria (e.g., lipopolysaccharide) resulting in inflammation and (2) bacterial metabolites of dietary compounds (e.g., SCFA from fiber), which have biological activities that regulate host functions. Gut microbiota has evolved with humans as a mutualistic partner, but dysbiosis in a form of altered gut metagenome and collected microbial activities, in combination with classic genetic and environmental factors, may promote the development of metabolic disorders. This paper reviews the available literature about the gut microbiota and aforementioned metabolic disorders and reveals the gaps in knowledge for future study. PMID:22315672

Horizontal gene transfer of chromosomal Type II toxin-antitoxin systems of Escherichia coli.

PubMed

Ramisetty, Bhaskar Chandra Mohan; Santhosh, Ramachandran Sarojini

2016-02-01

Type II toxin-antitoxin systems (TAs) are small autoregulated bicistronic operons that encode a toxin protein with the potential to inhibit metabolic processes and an antitoxin protein to neutralize the toxin. Most of the bacterial genomes encode multiple TAs. However, the diversity and accumulation of TAs on bacterial genomes and its physiological implications are highly debated. Here we provide evidence that Escherichia coli chromosomal TAs (encoding RNase toxins) are 'acquired' DNA likely originated from heterologous DNA and are the smallest known autoregulated operons with the potential for horizontal propagation. Sequence analyses revealed that integration of TAs into the bacterial genome is unique and contributes to variations in the coding and/or regulatory regions of flanking host genome sequences. Plasmids and genomes encoding identical TAs of natural isolates are mutually exclusive. Chromosomal TAs might play significant roles in the evolution and ecology of bacteria by contributing to host genome variation and by moderation of plasmid maintenance. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Innate and adaptive immune responses to cell death

PubMed Central

Rock, Kenneth L.; Lai, Jiann-Jyh; Kono, Hajime

2011-01-01

Summary The immune system plays an essential role in protecting the host against infections and to accomplish this task has evolved mechanisms to recognize microbes and destroy them. In addition, it monitors the health of cells and responds to ones that have been injured and die, even if this occurs under sterile conditions. This process is initiated when dying cells expose intracellular molecules that can be recognized by cells of the innate immune system. As a consequence of this recognition, dendritic cells are activated in ways that help to promote T-cell responses to antigens associated with the dying cells. In addition, macrophages are stimulated to produce the cytokine interleukin-1 that then acts on radioresistant parenchymal cells in the host in ways that drive a robust inflammatory response. In addition to dead cells, a number of other sterile particles and altered physiological states can similarly stimulate an inflammatory response and do so through common pathways involving the inflammasome and interleukin-1. These pathways underlie the pathogenesis of a number of diseases. PMID:21884177

Ecological Interactions of Bacteria in the Human Gut

NASA Astrophysics Data System (ADS)

Falony, Gwen; de Vuyst, Luc

The colon or large intestine is one of the most important organs of the human body (Macfarlane and Cummings, 1991). Moreover, its inhabitants, the colon microbiota, are the key elements of the human digestive ecosystem. The vast complexity of the human large-intestinal microbiota has inspired researchers to consider it as an organ itself, located inside the colon and acquired postnatally (Bäckhed et al., 2005; Zocco et al., 2007). From a physiologist's point of view, this image of the colon microbiota is relevant: like an organ, it is composed of different cell lineages that communicate with both one another and the host; it consumes, stores, and redistributes energy; it mediates physiologically important chemical transformations; and it is able to maintain and repair itself through self-replication (Bäckhed et al., 2005). As a microbial organ, the human colon community does not only broaden the digestive abilities of the host (Gill et al., 2006), but also influences body processes far beyond digestion (Roberfroid, 2005b; Turnbaugh et al., 2007).

Procession to pediatric bacteremia and sepsis: covert operations and failures in diplomacy.

PubMed

Bateman, Stacey L; Seed, Patrick C

2010-07-01

Despite advances in diagnosis and treatment, bacterial sepsis remains a major cause of pediatric morbidity and mortality, particularly among neonates, the critically ill, and the growing immunocompromised patient population. Sepsis is the end point of a complex and dynamic series of events in which both host and microbial factors drive high morbidity and potentially lethal physiologic alterations. In this article we provide a succinct overview of the events that lead to pediatric bloodstream infections (BSIs) and sepsis, with a focus on the molecular mechanisms used by bacteria to subvert host barriers and local immunity to gain access to and persist within the systemic circulation. In the events preceding and during BSI and sepsis, Gram-positive and Gram-negative pathogens use a battery of factors for translocation, inhibition of immunity, molecular mimicry, intracellular survival, and nutrient scavenging. Gaps in understanding the molecular pathogenesis of bacterial BSIs and sepsis are highlighted as opportunities to identify and develop new therapeutics.

Chemical regulation of body feather microbiota in a wild bird.

PubMed

Jacob, Staffan; Sallé, Louis; Zinger, Lucie; Chaine, Alexis S; Ducamp, Christine; Boutault, Léa; Russell, Andrew F; Heeb, Philipp

2018-04-01

The microbiota has a broad range of impacts on host physiology and behaviour, pointing out the need to improve our comprehension of the drivers of host-microbiota composition. Of particular interest is whether the microbiota is acquired passively, or whether and to what extent hosts themselves shape the acquisition and maintenance of their microbiota. In birds, the uropygial gland produces oily secretions used to coat feathers that have been suggested to act as an antimicrobial defence mechanism regulating body feather microbiota. However, our comprehension of this process is still limited. In this study, we for the first time coupled high-throughput sequencing of the microbiota of both body feathers and the direct environment (i.e., the nest) in great tits with chemical analyses of the composition of uropygial gland secretions to examine whether host chemicals have either specific effects on some bacteria or nonspecific broad-spectrum effects on the body feather microbiota. Using a network approach investigating the patterns of co-occurrence or co-exclusions between chemicals and bacteria within the body feather microbiota, we found no evidence for specific promicrobial or antimicrobial effects of uropygial gland chemicals. However, we found that one group of chemicals was negatively correlated to bacterial richness on body feathers, and a higher production of these chemicals was associated with a poorer body feather bacterial richness compared to the nest microbiota. Our study provides evidence that chemicals produced by the host might function as a nonspecific broad-spectrum antimicrobial defence mechanism limiting colonization and/or maintenance of bacteria on body feathers, providing new insight about the drivers of the host's microbiota composition in wild organisms. © 2018 John Wiley & Sons Ltd.

Chewing the fat: lipid metabolism and homeostasis during M. tuberculosis infection.

PubMed

Lovewell, Rustin R; Sassetti, Christopher M; VanderVen, Brian C

2016-02-01

The interplay between Mycobacterium tuberculosis lipid metabolism, the immune response and lipid homeostasis in the host creates a complex and dynamic pathogen-host interaction. Advances in imaging and metabolic analysis techniques indicate that M. tuberculosis preferentially associates with foamy cells and employs multiple physiological systems to utilize exogenously derived fatty-acids and cholesterol. Moreover, novel insights into specific host pathways that control lipid accumulation during infection, such as the PPARγ and LXR transcriptional regulators, have begun to reveal mechanisms by which host immunity alters the bacterial micro-environment. As bacterial lipid metabolism and host lipid regulatory pathways are both important, yet inherently complex, components of active tuberculosis, delineating the heterogeneity in lipid trafficking within disease states remains a major challenge for therapeutic design. Copyright © 2015. Published by Elsevier Ltd.

Circadian clocks in symbiotic corals: the duet between Symbiodinium algae and their coral host.

PubMed

Sorek, Michal; Díaz-Almeyda, Erika M; Medina, Mónica; Levy, Oren

2014-04-01

To date, the association and synchronization between two organismal circadian clocks ticking in parallel as part of a meta-organism (termed a symbiotic association), have rarely been investigated. Reef-building corals exhibit complex rhythmic responses to diurnal, lunar, and annual changes. Understanding circadian, circatidal, and annual regulation in reef-building corals is complicated by the presence of photosynthetic endosymbionts, which have a profound physiochemical influence on the intracellular environment. How corals tune their animal-based clock machinery to respond to external cues while simultaneously responding to internal physiological changes imposed by the symbiont, is not clear. There is insufficient molecular or physiological evidence of the existence of a circadian pacemaker that controls the metabolism, photosynthesis, synchronized mass spawning, and calcification processes in symbiotic corals. In this review, we present current knowledge regarding the animal pacemaker and the symbiotic-algal pacemaker. We examine the evidence from behavioral, physiological, molecular, and evolutionary perspectives. We explain why symbiotic corals are an interesting model with which to study the complexities and evolution of the metazoan circadian clock. We also provide evidence of why the chronobiology of corals is fundamental and extremely important for explaining the biology, physiology, and metabolism of coral reefs. A deeper understanding of these complex issues can help explain coral mass spawning, one of the earth's greatest and most mysterious behavioral phenomena. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-dimensional cell culture models for investigating human viruses.

PubMed

He, Bing; Chen, Guomin; Zeng, Yi

2016-10-01

Three-dimensional (3D) culture models are physiologically relevant, as they provide reproducible results, experimental flexibility and can be adapted for high-throughput experiments. Moreover, these models bridge the gap between traditional two-dimensional (2D) monolayer cultures and animal models. 3D culture systems have significantly advanced basic cell science and tissue engineering, especially in the fields of cell biology and physiology, stem cell research, regenerative medicine, cancer research, drug discovery, and gene and protein expression studies. In addition, 3D models can provide unique insight into bacteriology, virology, parasitology and host-pathogen interactions. This review summarizes and analyzes recent progress in human virological research with 3D cell culture models. We discuss viral growth, replication, proliferation, infection, virus-host interactions and antiviral drugs in 3D culture models.

microRNA expression in the neural retina: Focus on Müller glia.

PubMed

Quintero, Heberto; Lamas, Mónica

2018-03-01

The neural retina hosts a unique specialized type of macroglial cell that not only preserves retinal homeostasis, function, and integrity but also may serve as a source of new neurons during regenerative processes: the Müller cell. Precise microRNA-driven mechanisms of gene regulation impel and direct the processes of Müller glia lineage acquisition from retinal progenitors during development, the triggering of their response to retinal degeneration and, in some cases, Müller cell reprogramming and regenerative events. In this review we survey the recent reports describing, through functional assays, the regulatory role of microRNAs in Müller cell physiology, differentiation potential, and retinal pathology. We discuss also the evidence based on expression analysis that points out the relevance of a Müller glia-specific microRNA signature that would orchestrate these processes. © 2017 Wiley Periodicals, Inc.

Fungal biology and agriculture: revisiting the field

USGS Publications Warehouse

Yarden, O.; Ebbole, D.J.; Freeman, S.; Rodriguez, R.J.; Dickman, M. B.

2003-01-01

Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant-fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous subdisciplines within fungal biology and pathology. These data provide unique opportunities for basic research and for engineering solutions to important agricultural problems. However, we also are faced with the challenge of data organization and mining to analyze the relationships between fungal and plant genomes and to elucidate the physiological function of pertinent DNA sequences. We present our perspective of fungal biology and agriculture, including administrative and political challenges to plant protection research.

Mesenchymal stem cell-derived microparticles: a promising therapeutic strategy.

PubMed

Tan, Xi; Gong, Yong-Zhen; Wu, Ping; Liao, Duan-Fang; Zheng, Xi-Long

2014-08-18

Mesenchymal stem cells (MSCs) are multipotent stem cells that give rise to various cell types of the mesodermal germ layer. Because of their unique ability to home in on injured and cancerous tissues, MSCs are of great potential in regenerative medicine. MSCs also contribute to reparative processes in different pathological conditions, including cardiovascular diseases and cancer. However, many studies have shown that only a small proportion of transplanted MSCs can actually survive and be incorporated into host tissues. The effects of MSCs cannot be fully explained by their number. Recent discoveries suggest that microparticles (MPs) derived from MSCs may be important for the physiological functions of their parent. Though the physiological role of MSC-MPs is currently not well understood, inspiring results indicate that, in tissue repair and anti-cancer therapy, MSC-MPs have similar pro-regenerative and protective properties as their cellular counterparts. Thus, MSC-MPs represent a promising approach that may overcome the obstacles and risks associated with the use of native or engineered MSCs.

Mesenchymal Stem Cell-Derived Microparticles: A Promising Therapeutic Strategy

PubMed Central

Tan, Xi; Gong, Yong-Zhen; Wu, Ping; Liao, Duan-Fang; Zheng, Xi-Long

2014-01-01

Mesenchymal stem cells (MSCs) are multipotent stem cells that give rise to various cell types of the mesodermal germ layer. Because of their unique ability to home in on injured and cancerous tissues, MSCs are of great potential in regenerative medicine. MSCs also contribute to reparative processes in different pathological conditions, including cardiovascular diseases and cancer. However, many studies have shown that only a small proportion of transplanted MSCs can actually survive and be incorporated into host tissues. The effects of MSCs cannot be fully explained by their number. Recent discoveries suggest that microparticles (MPs) derived from MSCs may be important for the physiological functions of their parent. Though the physiological role of MSC-MPs is currently not well understood, inspiring results indicate that, in tissue repair and anti-cancer therapy, MSC-MPs have similar pro-regenerative and protective properties as their cellular counterparts. Thus, MSC-MPs represent a promising approach that may overcome the obstacles and risks associated with the use of native or engineered MSCs. PMID:25196436

An inside look at the sensory biology of triatomines.

PubMed

Barrozo, Romina B; Reisenman, Carolina E; Guerenstein, Pablo; Lazzari, Claudio R; Lorenzo, Marcelo G

Although kissing bugs (Triatominae: Reduviidae) are perhaps best known as vectors of Chagas disease, they are important experimental models in studies of insect sensory physiology, pioneered by the seminal studies of Wigglesworth and Gillet more than eighty years ago. Since then, many investigations have revealed that the thermal, hygric, visual and olfactory senses play critical roles in the orientation of these blood-sucking insects towards hosts. Here we review the current knowledge about the role of these sensory systems, focussing on relevant stimuli, sensory structures, receptor physiology and the molecular players involved in the complex and cryptic behavioural repertoire of these nocturnal insects. Odours are particularly relevant, as they are involved in host search and are used for sexual, aggregation and alarm communication. Tastants are critical for a proper recognition of hosts, food and conspecifics. Heat and relative humidity mediate orientation towards hosts and are also important for the selection of resting places. Vision, which mediates negative phototaxis and flight dispersion, is also critical for modulating shelter use and mediating escape responses. The molecular bases underlying the detection of sensory stimuli started to be uncovered by means of functional genetics due to both the recent publication of the genome sequence of Rhodnius prolixus and the availability of modern genome editing techniques. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12.

PubMed

Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K; Cai, Xingsheng; Wang, Xiaoxue

2015-11-04

Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions.

Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12

PubMed Central

Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K.; Cai, Xingsheng; Wang, Xiaoxue

2015-01-01

Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions. PMID:26530864

Host tolerance, not symbiont tolerance, determines the distribution of coral species in relation to their environment at a Central Pacific atoll

NASA Astrophysics Data System (ADS)

Wicks, L. C.; Gardner, J. P. A.; Davy, S. K.

2012-06-01

Tolerance of environmental variables differs between corals and their dinoflagellate symbionts ( Symbiodinium spp.), controlling the holobiont's (host and symbiont combined) resilience to environmental stress. However, the ecological role that environmental variables play in holobiont distribution remains poorly understood. We compared the drivers of symbiont and coral species distributions at Palmyra Atoll, a location with a range of reef environments from low to high sediment concentrations (1-52 g dry weight m-2 day-1). We observed uniform holobiont partnerships across the atoll (e.g. Montipora spp. with Symbiodinium type C15 at all sites). Multivariate analysis revealed that field-based estimates of settling sediment predominantly explained the spatial variation of coral species among sites ( P < 0.01). However, none of the environmental variables measured (sedimentation, temperature, chlorophyll concentration, salinity) affected symbiont distribution. The discord between environmental variables and symbiont distributions suggests that the symbionts are physiologically tolerant of the variable environmental regime across this location and that the distribution of different host-symbiont combinations present is largely dependent on coral rather than Symbiodinium physiology. The data highlight the importance of host tolerance to environmental stressors, which should be considered simultaneously with symbiont sensitivity when considering the impact of variations in environmental conditions on coral communities.

Mechanical measurement of hydrogen bonded host-guest systems under non-equilibrium, near-physiological conditions.

PubMed

Naranjo, Teresa; Cerrón, Fernando; Nieto-Ortega, Belén; Latorre, Alfonso; Somoza, Álvaro; Ibarra, Borja; Pérez, Emilio M

2017-09-01

Decades after the birth of supramolecular chemistry, there are many techniques to measure noncovalent interactions, such as hydrogen bonding, under equilibrium conditions. As ensembles of molecules rapidly lose coherence, we cannot extrapolate bulk data to single-molecule events under non-equilibrium conditions, more relevant to the dynamics of biological systems. We present a new method that exploits the high force resolution of optical tweezers to measure at the single molecule level the mechanical strength of a hydrogen bonded host-guest pair out of equilibrium and under near-physiological conditions. We utilize a DNA reporter to unambiguously isolate single binding events. The Hamilton receptor-cyanuric acid host-guest system is used as a test bed. The force required to dissociate the host-guest system is ∼17 pN and increases with the pulling rate as expected for a system under non-equilibrium conditions. Blocking one of the hydrogen bonding sites results in a significant decrease of the force-to-break by 1-2 pN, pointing out the ability of the method to resolve subtle changes in the mechanical strength of the binding due to the individual H-bonding components. We believe the method will prove to be a versatile tool to address important questions in supramolecular chemistry.

Organizing a large-scale Physiology Understanding (PhUn) Week event at a science center.

PubMed

VanRyn, Valerie S; Poteracki, James M; Balzer, Micaela; Wehrwein, Erica A

2018-06-01

For the past 6 yr, the Department of Physiology at Michigan State University (MSU) has partnered with Impression 5 Science Center in Lansing, MI. Together, we host a day-long community engagement event on a Saturday each year in early November coinciding with the American Physiological Society's Physiology Understanding Week. The purpose was to provide a fun and memorable hands-on experience for children and families. This paper describes the detailed planning and logistics. The event takes place in the main exhibit space at the science center, generally has 15-17 physiology activities stations set up as booths run by volunteers, and the event runs as an open-house format. Three to five trained volunteers were needed per station for the full day. Since this was primarily based on undergraduate student volunteer involvement (a population already limited for time), morning, afternoon, and/or full-day shifts were offered to accommodate a variety of schedules. Additional set-up, clean-up, and general help was also recruited. Overall, ~100-150 MSU students, faculty, and staff members served as volunteers, alongside Impression 5 staff. Hosting the event at the science center generated a larger audience, aided in advertisement, and allowed for access to a large facility capable of handling the 600-1,000 attendees. The partnership facilitated the sharing of equipment and supplies for physiology demonstrations, allowed for activities on site in the chemistry laboratory space, and facilitated the growth of new community partnerships with local schools and groups who attended the event.

The Plant as Metaorganism and Research on Next-Generation Systemic Pesticides – Prospects and Challenges

PubMed Central

Vryzas, Zisis

2016-01-01

Systemic pesticides (SPs) are usually recommended for soil treatments and as seed coating agents and are taken up from the soil by involving various plant-mediated processes, physiological, and morphological attributes of the root systems. Microscopic insights and next-generation sequencing combined with bioinformatics allow us now to identify new functions and interactions of plant-associated bacteria and perceive plants as meta-organisms. Host symbiotic, rhizo-epiphytic, endophytic microorganisms and their functions on plants have not been studied yet in accordance with uptake, tanslocation and action of pesticides. Root tips exudates mediated by rhizobacteria could modify the uptake of specific pesticides while bacterial ligands and enzymes can affect metabolism and fate of pesticide within plant. Over expression of specific proteins in cell membrane can also modify pesticide influx in roots. Moreover, proteins and other membrane compartments are usually involved in pesticide modes of action and resistance development. In this article it is discussed what is known of the physiological attributes including apoplastic, symplastic, and trans-membrane transport of SPs in accordance with the intercommunication dictated by plant–microbe, cell to cell and intracellular signaling. Prospects and challenges for uptake, translocation, storage, exudation, metabolism, and action of SPs are given through the prism of new insights of plant microbiome. Interactions of soil applied pesticides with physiological processes, plant root exudates and plant microbiome are summarized to scrutinize challenges for the next-generation pesticides. PMID:28018306

Gut microbiota: puppeteer of the host juvenile growth.

PubMed

Schwarzer, Martin

2018-05-01

This review focuses on the recent discoveries about the impact of intestinal microbiota on mammalian host juvenile growth. Intestinal microbiota is a powerful modulator of many facets of multicellular host's physiology. Recent results from human field studies and animal research have clearly shown that not only the nutrition, but also the intestinal microbiota impacts host postnatal growth kinetics. Absence of microbiome leads to stunted growth in mammalian gnotobiotic models and changes in the composition of the intestinal microbiota can impact the postnatal growth kinetics both positively and negatively under normal nutritional conditions as well as in undernutrition. Strikingly, specific bacterial strains are able to interact with GH/IGF-1 somatotropic axis activity, thus directly impacting host juvenile development. Intestinal microbiota dictates the pace of host postnatal growth. This newly described role envisages that therapy with specific bacterial strains, together with re-nutritional strategies, might successfully alleviate the long-term sequelae of undernutrition during childhood in humans.

Growth, biomass, and fecundity of Bothriocephalus acheilognathi in a North Carolina cooling reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riggs, M.R.; Lemly, A.D.; Esch, G.W.

1987-10-01

An investigation of differences in growth, maturation, biomass, and fecundity of Bothriocephalus acheilognathi in 3 host species was conducted on metapopulations from 3 distinct communities in Belews Lake, North Carolina. The results indicated that host-specific differences in growth and biomass were additive among metapopulations from different localities. However, species-specific differences in maturation and fecundity exhibited differential variation between the sites. These site X host interactions were related to host-specific differences in bioaccumulation of selenium at sites that were exposed to effluent from a coal-fired power plant. Significant (alpha = 0.001) statistical associations were observed between selenium concentration in tapeworm tissuemore » and fecundity measures. The results of this study demonstrate that host suitability is determined by morphological, physiological, and behavioral differences in the host species which affect transmission dynamics and the quality and stability of the enteric environment.« less

Worldwide exploration of the microbiome harbored by the cnidarian model, Exaiptasia pallida (Agassiz in Verrill, 1864) indicates a lack of bacterial association specificity at a lower taxonomic rank

PubMed Central

Brown, Tanya; Otero, Christopher; Grajales, Alejandro; Rodriguez, Estefania

2017-01-01

Examination of host-microbe interactions in early diverging metazoans, such as cnidarians, is of great interest from an evolutionary perspective to understand how host-microbial consortia have evolved. To address this problem, we analyzed whether the bacterial community associated with the cosmopolitan and model sea anemone Exaiptasia pallida shows specific patterns across worldwide populations ranging from the Caribbean Sea, and the Atlantic and Pacific oceans. By comparing sequences of the V1–V3 hypervariable regions of the bacterial 16S rRNA gene, we revealed that anemones host a complex and diverse microbial community. When examined at the phylum level, bacterial diversity and abundance associated with E. pallida are broadly conserved across geographic space with samples, containing largely Proteobacteria and Bacteroides. However, the species-level makeup within these phyla differs drastically across space suggesting a high-level core microbiome with local adaptation of the constituents. Indeed, no bacterial OTU was ubiquitously found in all anemones samples. We also revealed changes in the microbial community structure after rearing anemone specimens in captivity within a period of four months. Furthermore, the variation in bacterial community assemblages across geographical locations did not correlate with the composition of microalgal Symbiodinium symbionts. Our findings contrast with the postulation that cnidarian hosts might actively select and maintain species-specific microbial communities that could have resulted from an intimate co-evolution process. The fact that E. pallida is likely an introduced species in most sampled localities suggests that this microbial turnover is a relatively rapid process. Our findings suggest that environmental settings, not host specificity, seem to dictate bacterial community structure associated with this sea anemone. More than maintaining a specific composition of bacterial species some cnidarians associate with a wide range of bacterial species as long as they provide the same physiological benefits towards the maintenance of a healthy host. The examination of the previously uncharacterized bacterial community associated with the cnidarian sea anemone model E. pallida is the first global-scale study of its kind. PMID:28533949

Getting ready for host invasion: elevated expression and action of xyloglucan endotransglucosylases/hydrolases in developing haustoria of the holoparasitic angiosperm Cuscuta.

PubMed

Olsen, Stian; Striberny, Bernd; Hollmann, Julien; Schwacke, Rainer; Popper, Zoë; Krause, Kirsten

2016-02-01

Changes in cell walls have been previously observed in the mature infection organ, or haustorium, of the parasitic angiosperm Cuscuta, but are not equally well charted in young haustoria. In this study, we focused on the molecular processes in the early stages of developing haustoria; that is, before the parasite engages in a physiological contact with its host. We describe first the identification of differentially expressed genes in young haustoria whose development was induced by far-red light and tactile stimuli in the absence of a host plant by suppression subtractive hybridization. To improve sequence information and to aid in the identification of the obtained candidates, reference transcriptomes derived from two species of Cuscuta, C. gronovii and C. reflexa, were generated. Subsequent quantitative gene expression analysis with different tissues of C. reflexa revealed that among the genes that were up-regulated in young haustoria, two xyloglucan endotransglucosylase/hydrolase (XTH) genes were highly expressed almost exclusively at the onset of haustorium development. The same expression pattern was also found for the closest XTH homologues from C. gronovii. In situ assays for XTH-specific action suggested that xyloglucan endotransglucosylation was most pronounced in the cell walls of the swelling area of the haustorium facing the host plant, but was also detectable in later stages of haustoriogenesis. We propose that xyloglucan remodelling by Cuscuta XTHs prepares the parasite for host infection and possibly aids the invasive growth of the haustorium. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Universality of human microbial dynamics

NASA Astrophysics Data System (ADS)

Bashan, Amir; Gibson, Travis E.; Friedman, Jonathan; Carey, Vincent J.; Weiss, Scott T.; Hohmann, Elizabeth L.; Liu, Yang-Yu

2016-06-01

Human-associated microbial communities have a crucial role in determining our health and well-being, and this has led to the continuing development of microbiome-based therapies such as faecal microbiota transplantation. These microbial communities are very complex, dynamic and highly personalized ecosystems, exhibiting a high degree of inter-individual variability in both species assemblages and abundance profiles. It is not known whether the underlying ecological dynamics of these communities, which can be parameterized by growth rates, and intra- and inter-species interactions in population dynamics models, are largely host-independent (that is, universal) or host-specific. If the inter-individual variability reflects host-specific dynamics due to differences in host lifestyle, physiology or genetics, then generic microbiome manipulations may have unintended consequences, rendering them ineffective or even detrimental. Alternatively, microbial ecosystems of different subjects may exhibit universal dynamics, with the inter-individual variability mainly originating from differences in the sets of colonizing species. Here we develop a new computational method to characterize human microbial dynamics. By applying this method to cross-sectional data from two large-scale metagenomic studies—the Human Microbiome Project and the Student Microbiome Project—we show that gut and mouth microbiomes display pronounced universal dynamics, whereas communities associated with certain skin sites are probably shaped by differences in the host environment. Notably, the universality of gut microbial dynamics is not observed in subjects with recurrent Clostridium difficile infection but is observed in the same set of subjects after faecal microbiota transplantation. These results fundamentally improve our understanding of the processes that shape human microbial ecosystems, and pave the way to designing general microbiome-based therapies.

Evaluating Stress Physiology and Parasite Infection Parameters in the Translocation of Critically Endangered Woylies (Bettongia penicillata).

PubMed

Hing, Stephanie; Northover, Amy S; Narayan, Edward J; Wayne, Adrian F; Jones, Krista L; Keatley, Sarah; Thompson, R C Andrew; Godfrey, Stephanie S

2017-03-01

Translocation can be stressful for wildlife. Stress may be important in fauna translocation because it has been suggested that it can exacerbate the impact of infectious disease on translocated wildlife. However, few studies explore this hypothesis by measuring stress physiology and infection indices in parallel during wildlife translocations. We analysed faecal cortisol metabolite (FCM) concentration and endoparasite parameters (nematodes, coccidians and haemoparasites) in a critically endangered marsupial, the woylie (Bettongia penicillata), 1-3 months prior to translocation, at translocation, and 6 months later. FCM for both translocated and resident woylies was significantly higher after translocation compared to before or at translocation. In addition, body condition decreased with increasing FCM after translocation. These patterns in host condition and physiology may be indicative of translocation stress or stress associated with factors independent of the translocation. Parasite factors also influenced FCM in translocated woylies. When haemoparasites were detected, there was a significant negative relationship between strongyle egg count and FCM. This may reflect the influence of glucocorticoids on the immune response to micro- and macro-parasites. Our results indicate that host physiology and infection patterns can change significantly during translocation, but further investigation is required to determine how these patterns influence translocation success.

Transcriptome of Pneumocystis carinii during fulminate infection: carbohydrate metabolism and the concept of a compatible parasite.

PubMed

Cushion, Melanie T; Smulian, A George; Slaven, Bradley E; Sesterhenn, Tom; Arnold, Jonathan; Staben, Chuck; Porollo, Aleksey; Adamczak, Rafal; Meller, Jarek

2007-05-09

Members of the genus Pneumocystis are fungal pathogens that cause pneumonia in a wide variety of mammals with debilitated immune systems. Little is known about their basic biological functions, including life cycle, since no species can be cultured continuously outside the mammalian lung. To better understand the pathological process, about 4500 ESTS derived from sequencing of the poly(A) tail ends of P. carinii mRNAs during fulminate infection were annotated and functionally characterized as unassembled reads, and then clustered and reduced to a unigene set with 1042 members. Because of the presence of sequences from other microbial genomes and the rat host, the analysis and compression to a unigene set was necessarily an iterative process. BLASTx analysis of the unassembled reads (UR) vs. the Uni-Prot and TREMBL databases revealed 56% had similarities to existing polypeptides at E values of

Transcriptome of Pneumocystis carinii during Fulminate Infection: Carbohydrate Metabolism and the Concept of a Compatible Parasite

PubMed Central

Sesterhenn, Tom; Arnold, Jonathan; Staben, Chuck; Porollo, Aleksey; Adamczak, Rafal; Meller, Jarek

2007-01-01

Members of the genus Pneumocystis are fungal pathogens that cause pneumonia in a wide variety of mammals with debilitated immune systems. Little is known about their basic biological functions, including life cycle, since no species can be cultured continuously outside the mammalian lung. To better understand the pathological process, about 4500 ESTS derived from sequencing of the poly(A) tail ends of P. carinii mRNAs during fulminate infection were annotated and functionally characterized as unassembled reads, and then clustered and reduced to a unigene set with 1042 members. Because of the presence of sequences from other microbial genomes and the rat host, the analysis and compression to a unigene set was necessarily an iterative process. BLASTx analysis of the unassembled reads (UR) vs. the Uni-Prot and TREMBL databases revealed 56% had similarities to existing polypeptides at E values of≤10−6, with the remainder lacking any significant homology. The most abundant transcripts in the UR were associated with stress responses, energy production, transcription and translation. Most (70%) of the UR had similarities to proteins from filamentous fungi (e.g., Aspergillus, Neurospora) and existing P. carinii gene products. In contrast, similarities to proteins of the yeast-like fungi, Schizosaccharomyces pombe and Saccharomyces cerevisiae, predominated in the unigene set. Gene Ontology analysis using BLAST2GO revealed P. carinii dedicated most of its transcripts to cellular and physiological processes (∼80%), molecular binding and catalytic activities (∼70%), and were primarily derived from cell and organellar compartments (∼80%). KEGG Pathway mapping showed the putative P. carinii genes represented most standard metabolic pathways and cellular processes, including the tricarboxylic acid cycle, glycolysis, amino acid biosynthesis, cell cycle and mitochondrial function. Several gene homologs associated with mating, meiosis, and sterol biosynthesis in fungi were identified. Genes encoding the major surface glycoprotein family (MSG), heat shock (HSP70), and proteases (PROT/KEX) were the most abundantly expressed of known P. carinii genes. The apparent presence of many metabolic pathways in P. carinii, sexual reproduction within the host, and lack of an invasive infection process in the immunologically intact host suggest members of the genus Pneumocystis may be adapted parasites and have a compatible relationship with their mammalian hosts. This study represents the first characterization of the expressed genes of a non-culturable fungal pathogen of mammals during the infective process. PMID:17487271

A Model System for Studying the Transcriptomic and Physiological Changes Associated with Mammalian Host-Adaptation by Leptospira interrogans Serovar Copenhageni

PubMed Central

Caimano, Melissa J.; Sivasankaran, Sathesh K.; Allard, Anna; Hurley, Daniel; Hokamp, Karsten; Grassmann, André A.; Hinton, Jay C. D.; Nally, Jarlath E.

2014-01-01

Leptospirosis, an emerging zoonotic disease with worldwide distribution, is caused by spirochetes belonging to the genus Leptospira. More than 500,000 cases of severe leptospirosis are reported annually, with >10% of these being fatal. Leptospires can survive for weeks in suitably moist conditions before encountering a new host. Reservoir hosts, typically rodents, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. In humans, leptospires can cause a variety of clinical manifestations, ranging from asymptomatic or mild fever to severe icteric (Weil's) disease and pulmonary haemorrhage. Currently, little is known about how Leptospira persist within a reservoir host. Prior in vitro studies have suggested that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. However, no study has examined gene expression by leptospires within a mammalian host-adapted state. To obtain a more faithful representation of how leptospires respond to host-derived signals, we used RNA-Seq to compare the transcriptome of L. interrogans cultivated within dialysis membrane chambers (DMCs) implanted into the peritoneal cavities of rats with that of organisms grown in vitro. In addition to determining the relative expression levels of “core” housekeeping genes under both growth conditions, we identified 166 genes that are differentially-expressed by L. interrogans in vivo. Our analyses highlight physiological aspects of host adaptation by leptospires relating to heme uptake and utilization. We also identified 11 novel non-coding transcripts that are candidate small regulatory RNAs. The DMC model provides a facile system for studying the transcriptional and antigenic changes associated with mammalian host-adaption, selection of targets for mutagenesis, and the identification of previously unrecognized virulence determinants. PMID:24626166

Overview on the effects of parasites on fish health

USGS Publications Warehouse

Iwanowicz, D.D.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

2011-01-01

It is believed by many that parasites are only as important as the fish they infect. Parasites are ubiquitous, primarily surviving in a dynamic equilibrium with their host(s) and they are often overlooked in fish health assessments. Changes in the environment, both anthropogenic and environmental, can alter the parasite/host equilibrium and cause disease or mortality in fish. Therefore it is imperative that we have knowledge of both parasites and parasitic communities within a given population. When fish kills occur, it can often be associated with changes in parasite density and community composition. Often the damage associated with these fish is relative to the rate of infestation with the parasite; a fish that is lightly infected will show few signs of the parasite, while a heavily infected fish may become physiologically impaired and even die. Parasites can cause mechanical damage (fusion of gill lamellae, tissue replacement), physiological damage (cell proliferation, immunomodulation, detrimental behavioral responses, altered growth) and reproductive damage. As parasitism is the most common lifestyle on the planet, understanding its role in the environment may help researchers understand changes in a given fish population or stream ecosystem.

Blood monocyte alteration caused by a hematozoan infection in the lizard Ameiva ameiva (Reptilia: Teiidae).

PubMed

Silva, Edilene O; Diniz, José P; Alberio, Sanny; Lainson, Ralph; de Souza, Wanderley; DaMatta, Renato A

2004-08-01

Although hematozoa have been described from many different host species, little is known about the infection and its relationship to the physiology of the host. We studied a hematozoan, regarded as a species of Lainsonia Landau, 1973 (Lankestereliidae), which infects the monocytes of the lizard Ameiva ameiva. The infected animals show a huge monocytosis and morphological changes in the monocytes. Ultrastructurally, the parasite has an apical complex, dense bodies, electron lucent structures, plasma membrane projections and folding which may be involved with nutrition. The parasite occupies a parasitophorous vacuole (PV) exhibiting high electron density at its membrane. Mitochondria and the Golgi complex of the monocytes were concentrated around the PV, and the cytoplasm was totally occupied by a vimentin type of intermediate filament radiating from (or to) the cytosolic surface of the PV. Vimentin was identified by diameter measurement, immunofluorescence and immunoelectron microscopy. These observations indicate that this infection alters the physiological state of the host and suggest that this parasite has the ability to modify monocyte vimentin assembly.

Towards microbial fermentation metabolites as markers for health benefits of prebiotics.

PubMed

Verbeke, Kristin A; Boobis, Alan R; Chiodini, Alessandro; Edwards, Christine A; Franck, Anne; Kleerebezem, Michiel; Nauta, Arjen; Raes, Jeroen; van Tol, Eric A F; Tuohy, Kieran M

2015-06-01

Available evidence on the bioactive, nutritional and putative detrimental properties of gut microbial metabolites has been evaluated to support a more integrated view of how prebiotics might affect host health throughout life. The present literature inventory targeted evidence for the physiological and nutritional effects of metabolites, for example, SCFA, the potential toxicity of other metabolites and attempted to determine normal concentration ranges. Furthermore, the biological relevance of more holistic approaches like faecal water toxicity assays and metabolomics and the limitations of faecal measurements were addressed. Existing literature indicates that protein fermentation metabolites (phenol, p-cresol, indole, ammonia), typically considered as potentially harmful, occur at concentration ranges in the colon such that no toxic effects are expected either locally or following systemic absorption. The endproducts of saccharolytic fermentation, SCFA, may have effects on colonic health, host physiology, immunity, lipid and protein metabolism and appetite control. However, measuring SCFA concentrations in faeces is insufficient to assess the dynamic processes of their nutrikinetics. Existing literature on the usefulness of faecal water toxicity measures as indicators of cancer risk seems limited. In conclusion, at present there is insufficient evidence to use changes in faecal bacterial metabolite concentrations as markers of prebiotic effectiveness. Integration of results from metabolomics and metagenomics holds promise for understanding the health implications of prebiotic microbiome modulation but adequate tools for data integration and interpretation are currently lacking. Similarly, studies measuring metabolite fluxes in different body compartments to provide a more accurate picture of their nutrikinetics are needed.

Towards understanding oral health.

PubMed

Zaura, Egija; ten Cate, Jacob M

2015-01-01

During the last century, dental research has focused on unraveling the mechanisms behind various oral pathologies, while oral health was typically described as the mere absence of oral diseases. The term 'oral microbial homeostasis' is used to describe the capacity of the oral ecosystem to maintain microbial community stability in health. However, the oral ecosystem itself is not stable: throughout life an individual undergoes multiple physiological changes while progressing through infancy, childhood, adolescence, adulthood and old age. Recent discussions on the definition of general health have led to the proposal that health is the ability of the individual to adapt to physiological changes, a condition known as allostasis. In this paper the allostasis principle is applied to the oral ecosystem. The multidimensionality of the host factors contributing to allostasis in the oral cavity is illustrated with an example on changes occurring in puberty. The complex phenomenon of oral health and the processes that prevent the ecosystem from collapsing during allostatic changes in the entire body are far from being understood. As yet individual components (e.g. hard tissues, microbiome, saliva, host response) have been investigated, while only by consolidating these and assessing their multidimensional interactions should we be able to obtain a comprehensive understanding of the ecosystem, which in turn could serve to develop rational schemes to maintain health. Adapting such a 'system approach' comes with major practical challenges for the entire research field and will require vast resources and large-scale multidisciplinary collaborations. 2015 S. Karger AG, Basel

The role of adipokines in chronic inflammation

PubMed Central

Mancuso, Peter

2016-01-01

Adipose tissue has traditionally been defined as connective tissue that stores excess calories in the form of triacylglycerol. However, the physiologic functions attributed to adipose tissue are expanding, and it is now well established that adipose tissue is an endocrine gland. Among the endocrine factors elaborated by adipose tissue are the adipokines; hormones, similar in structure to cytokines, produced by adipose tissue in response to changes in adipocyte triacylglycerol storage and local and systemic inflammation. They inform the host regarding long-term energy storage and have a profound influence on reproductive function, blood pressure regulation, energy homeostasis, the immune response, and many other physiologic processes. The adipokines possess pro- and anti-inflammatory properties and play a critical role in integrating systemic metabolism with immune function. In calorie restriction and starvation, proinflammatory adipokines decline and anti-inflammatory adipokines increase, which informs the host of energy deficits and contributes to the suppression of immune function. In individuals with normal metabolic status, there is a balance of pro- and anti-inflammatory adipokines. This balance shifts to favor proinflammatory mediators as adipose tissue expands during the development of obesity. As a consequence, the proinflammatory status of adipose tissue contributes to a chronic low-grade state of inflammation and metabolic disorders associated with obesity. These disturbances are associated with an increased risk of metabolic disease, type 2 diabetes, cardiovascular disease, and many other pathological conditions. This review focuses on the impact of energy homeostasis on the adipokines in immune function. PMID:27529061

Differential thermal response within inshore vs. offshore congeneric scleractinian coral species in Palau.

NASA Astrophysics Data System (ADS)

Hoadley, K. D.; Lewis, A.; Wham, D.; Pettay, D. T.; Kemp, D.; Warner, M.; Lajeunesse, T.

2016-02-01

The rock island reef habitats of Palau are an ideal location to study climate change effects to reefs, as corals there are exposed to average temperature and pCO2 conditions well above levels experienced at offshore reef locations. We examined the response of 6 coral species, Acropora muricata, Goniastrea sp, Porities rus, Cyphastrea sp, Porites cylindrical and Pachyseris sp, from both rock island and offshore habitats to high temperature (32 Celsius) for 15 days. With the exception of P. rus and P. cylindrica which harbored Symbiodinium C15 at both locations, other rock island corals harbored the thermally tolerant species Symbiodinium trenchii, whereas offshore colonies harbored clade C symbionts. A total of 15 separate host and symbiont physiological variables were utilized to assess thermal acclimation/stress response within each host/symbiont combination. Differences in photophysiology, algal cell volume and biochemical composition were observed for Symbiodinium trenchii within different host species, reflecting the importance of the host organism in mitigating the symbiont response. Similarly, the host thermal response was also dependent on symbiont type, with greater reductions in symbiont density occurring within the offshore colonies. Overall, prior exposure to warmer temperatures, elevated nutrient and pCO2 conditions, along with association with more robust symbionts allowed rock island corals to exhibit greater thermal tolerance toward high temperature. Importantly, the results herein for Symbiodinium trenchii physiological plasticity and thermal mitigation provides useful insight into the potential of scleractinian corals to acclimatize under future climate change scenarios.

Endophyte-Mediated Modulation of Defense-Related Genes and Systemic Resistance in Withania somnifera (L.) Dunal under Alternaria alternata Stress.

PubMed

Mishra, Aradhana; Singh, Satyendra Pratap; Mahfooz, Sahil; Singh, Surendra Pratap; Bhattacharya, Arpita; Mishra, Nishtha; Nautiyal, C S

2018-04-15

Endophytes have been explored and found to perform an important role in plant health. However, their effects on the host physiological function and disease management remain elusive. The present study aimed to assess the potential effects of endophytes, singly as well as in combination, in Withania somnifera (L.) Dunal, on various physiological parameters and systemic defense mechanisms against Alternaria alternata Seeds primed with the endophytic bacteria Bacillus amyloliquefaciens and Pseudomonas fluorescens individually and in combination demonstrated an enhanced vigor index and germination rate. Interestingly, plants treated with the two-microbe combination showed the lowest plant mortality rate (28%) under A. alternata stress. Physiological profiling of treated plants showed improved photosynthesis, respiration, transpiration, and stomatal conductance under pathogenic stress. Additionally, these endophytes not only augmented defense enzymes and antioxidant activity in treated plants but also enhanced the expression of salicylic acid- and jasmonic acid-responsive genes in the stressed plants. Reductions in reactive oxygen species (ROS) and reactive nitrogen species (RNS) along with enhanced callose deposition in host plant leaves corroborated well with the above findings. Altogether, the study provides novel insights into the underlying mechanisms behind the tripartite interaction of endophyte- A. alternata - W. somnifera and underscores their ability to boost plant health under pathogen stress. IMPORTANCE W. somnifera is well known for producing several medicinally important secondary metabolites. These secondary metabolites are required by various pharmaceutical sectors to produce life-saving drugs. However, the cultivation of W. somnifera faces severe challenge from leaf spot disease caused by A. alternata To keep pace with the rising demand for this plant and considering its capacity for cultivation under field conditions, the present study was undertaken to develop approaches to enhance production of W. somnifera through intervention using endophytes. Application of bacterial endophytes not only suppresses the pathogenicity of A. alternata but also mitigates excessive ROS/RNS generation via enhanced physiological processes and antioxidant machinery. Expression profiling of plant defense-related genes further validates the efficacy of bacterial endophytes against leaf spot disease. Copyright © 2018 American Society for Microbiology.

NS1-binding protein abrogates the elevation of cell viability by the influenza A virus NS1 protein in association with CRKL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyazaki, Masaya; Nishihara, Hiroshi, E-mail: hnishihara@med.hokudai.ac.jp; Hasegawa, Hideki

Highlights: •NS1 induced excessive phosphorylation of ERK and elevated cell viability. •NS1-BP expression and CRKL knockdown abolished survival effect of NS1. •NS1-BP and NS1 formed the complex through the interaction with CRKL-SH3(N). -- Abstract: The influenza A virus non-structural protein 1 (NS1) is a multifunctional virulence factor consisting of an RNA binding domain and several Src-homology (SH) 2 and SH3 binding motifs, which promotes virus replication in the host cell and helps to evade antiviral immunity. NS1 modulates general host cell physiology in association with various cellular molecules including NS1-binding protein (NS1-BP) and signaling adapter protein CRK-like (CRKL), while themore » physiological role of NS1-BP during influenza A virus infection especially in association with NS1 remains unclear. In this study, we analyzed the intracellular association of NS1-BP, NS1 and CRKL to elucidate the physiological roles of these molecules in the host cell. In HEK293T cells, enforced expression of NS1 of A/Beijing (H1N1) and A/Indonesia (H5N1) significantly induced excessive phosphorylation of ERK and elevated cell viability, while the over-expression of NS1-BP and the abrogation of CRKL using siRNA abolished such survival effect of NS1. The pull-down assay using GST-fusion CRKL revealed the formation of intracellular complexes of NS1-BP, NS1 and CRKL. In addition, we identified that the N-terminus SH3 domain of CRKL was essential for binding to NS1-BP using GST-fusion CRKL-truncate mutants. This is the first report to elucidate the novel function of NS1-BP collaborating with viral protein NS1 in modulation of host cell physiology. In addition, an alternative role of adaptor protein CRKL in association with NS1 and NS1-BP during influenza A virus infection is demonstrated.« less

Lactobacillus fermentum NS9 restores the antibiotic induced physiological and psychological abnormalities in rats.

PubMed

Wang, T; Hu, X; Liang, S; Li, W; Wu, X; Wang, L; Jin, F

2015-01-01

Gut microbiota play a vital role in maintaining the health of the host. Many factors affect gut microbiota; application of broad range antibiotics disturb microbiota, while probiotic application protects the microbiota. To investigate how probiotics alter the physiological and psychological changes induced by antibiotics, we tested the performance of ampicillin-treated rats in the presence or absence of Lactobacillus fermentum strain NS9, in elevated plus maze and Morris water maze. The results showed that NS9 normalised the composition of gut microbiota and alleviated the ampicillin-induced inflammation in the colon. The levels of the mineralocorticoid and N-methyl-D-aspartate receptors were also elevated in the hippocampus of the ampillicin+NS9 treated group. NS9 administration also reduced the anxiety-like behaviour and alleviated the ampicillin-induced impairment in memory retention. These findings suggest that NS9 is beneficial to the host, because it restores the physiological and psychological abnormalities induced by ampicillin. Our results highlight how gut contents regulate the brain, and shed light on the clinical applications of probiotics to treat the side effect of antibiotics and mental disorders.

Impact of simulated microgravity on the normal developmental time line of an animal-bacteria symbiosis

PubMed Central

Foster, Jamie S.; Khodadad, Christina L. M.; Ahrendt, Steven R.; Parrish, Mirina L.

2013-01-01

The microgravity environment during space flight imposes numerous adverse effects on animal and microbial physiology. It is unclear, however, how microgravity impacts those cellular interactions between mutualistic microbes and their hosts. Here, we used the symbiosis between the host squid Euprymna scolopes and its luminescent bacterium Vibrio fischeri as a model system. We examined the impact of simulated microgravity on the timeline of bacteria-induced development in the host light organ, the site of the symbiosis. To simulate the microgravity environment, host squid and symbiosis-competent bacteria were incubated together in high-aspect ratio rotating wall vessel bioreactors and examined throughout the early stages of the bacteria-induced morphogenesis. The host innate immune response was suppressed under simulated microgravity; however, there was an acceleration of bacteria-induced apoptosis and regression in the host tissues. These results suggest that the space flight environment may alter the cellular interactions between animal hosts and their natural healthy microbiome. PMID:23439280

Endoscopic sensing of pH in the distal lung (Conference Presentation)

NASA Astrophysics Data System (ADS)

Choudhury, Debaditya; Tanner, Michael G.; McAughtrie, Sarah; Yu, Fei; Mills, Bethany; Choudhary, Tushar R.; Seth, Sohan; Craven, Thomas; Stone, James M.; Mati, Ioulia K.; Campbell, Colin J.; Bradley, Mark; Williams, Christopher K.; Dhaliwal, Kevin; Birks, Timothy A.; Thomson, Robert R.

2017-04-01

In healthy humans, the physiological state in the distal lung alveolar acinar units is tightly regulated by normal homeostatic mechanisms. Pulmonary abnormalities such as chronic obstructive pulmonary disease, that are characterized by recurrent cycles of inflammation and infection involving dense infiltration by myeloid derived peripheral blood cells, may result in significant perturbation of the homeostatic baselines of physiology in addition to host tissue damage. Therefore, the ability to quantify and monitor physiology (e.g. pH, glucose level, oxygen tension) within the alveolar acinar units would provide a key biomarker of distal lung innate defence. Although in vitro modeling of fundamental biological processes show remarkable sensitivity to physiological aberrations, little is known about the physiological state of the distal lung due to the inability to concurrently access the alveolar sacs and perform real-time sensing. Here we report on previously unobtainable measurements of alveolar pH using a fiber-optic optrode and surface enhanced Raman spectroscopy (SERS) and show that alveolar pH changes in response to ventilation. The endoscope-deployable optrode consisted of para-mercaptobenzoic acid functionalized 150 nm gold nanoshells located at the distal end, and an asymmetric dual-core optical fiber designed for spatially separated optical pump delivery and SERS signal collection in order to circumvent the unwanted Raman signal originating from the fiber itself. We demonstrate a 100-fold increase in SERS signal-to-fiber background ratio and pH sensing at multiple sites in the respiratory acinar units of a whole ex vivo ovine lung model with a measurement accuracy of ± 0.07 pH units.

Competitive growth, energy allocation, and host modification in the acanthocephalan Acanthocephalus dirus: field data.

PubMed

Caddigan, Sara C; Pfenning, Alaina C; Sparkes, Timothy C

2017-01-01

The acanthocephalan Acanthocephalus dirus is a trophically transmitted parasite that modifies both the physiology and behavior of its intermediate host (isopod) prior to transmission to its definitive host (fish). Infected isopods often contain multiple A. dirus individuals and we examined the relationships between host sharing, body size, energy content, and host modification to determine if host sharing was costly and if these costs could influence the modification of host behavior (mating behavior). Using field-based measures of parasite energy content (glycogen, lipid) and parasite body size (volume), we showed that host sharing was costly in terms of energy content but not in terms of body size. Analysis of the predictors of host behavior revealed that energy content, and body size, were not predictors of host behavior. Of the variables examined, parasite intensity was the only predictor of host behavior. Hosts that contained more parasites were less likely to be modified (i.e., less likely to undergo mating suppression). We suggest that intraspecific competition influenced parasite energy content and that the costs associated with competition are likely to shape the strategy of growth and energy allocation adopted by the parasites. These costs did not appear to have a direct effect on the modification of host mating behavior.

Cross-regulatory circuit between AHR and microbiota.

PubMed

Ji, Jian; Qu, Hao

2018-01-29

The gut microbes have a close symbiotic relationship with their host. Interactions between host and the microbiota affect the nutritional, immunological, and physiological status of the host. The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that mediates the toxicity of xenobiotics. Recently, the relationship between the gut microbiota and AHR has attracted the attention of many researchers. The AHR influences the intestinal microbiota population and mediates host-microbe homeostasis. Interestingly, the gut microbiota also produces ligands of AHR from bacterial metabolism and thereby activates the AHR signaling pathway. This review presents current knowledge of the cross-regulatory circuit between the AHR and intestinal microbiota. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Bacteria and wound healing.

PubMed

Edwards, Ruth; Harding, Keith G

2004-04-01

Wound healing is a complex process with many potential factors that can delay healing. There is increasing interest in the effects of bacteria on the processes of wound healing. All chronic wounds are colonized by bacteria, with low levels of bacteria being beneficial to the wound healing process. Wound infection is detrimental to wound healing, but the diagnosis and management of wound infection is controversial, and varies between clinicians. There is increasing recognition of the concept of critical colonization or local infection, when wound healing may be delayed in the absence of the typical clinical features of infection. The progression from wound colonization to infection depends not only on the bacterial count or the species present, but also on the host immune response, the number of different species present, the virulence of the organisms and synergistic interactions between the different species. There is increasing evidence that bacteria within chronic wounds live within biofilm communities, in which the bacteria are protected from host defences and develop resistance to antibiotic treatment. An appreciation of the factors affecting the progression from colonization to infection can help clinicians with the interpretation of clinical findings and microbiological investigations in patients with chronic wounds. An understanding of the physiology and interactions within multi-species biofilms may aid the development of more effective methods of treating infected and poorly healing wounds. The emergence of consensus guidelines has helped to optimize clinical management.

Systemic bacterial infection and immune defense phenotypes in Drosophila melanogaster.

PubMed

Khalil, Sarah; Jacobson, Eliana; Chambers, Moria C; Lazzaro, Brian P

2015-05-13

The fruit fly Drosophila melanogaster is one of the premier model organisms for studying the function and evolution of immune defense. Many aspects of innate immunity are conserved between insects and mammals, and since Drosophila can readily be genetically and experimentally manipulated, they are powerful for studying immune system function and the physiological consequences of disease. The procedure demonstrated here allows infection of flies by introduction of bacteria directly into the body cavity, bypassing epithelial barriers and more passive forms of defense and allowing focus on systemic infection. The procedure includes protocols for the measuring rates of host mortality, systemic pathogen load, and degree of induction of the host immune system. This infection procedure is inexpensive, robust and quantitatively repeatable, and can be used in studies of functional genetics, evolutionary life history, and physiology.

Persistent bacterial infections, antibiotic tolerance, and the oxidative stress response

PubMed Central

Grant, Sarah Schmidt; Hung, Deborah T.

2013-01-01

Certain bacterial pathogens are able to evade the host immune system and persist within the human host. The consequences of persistent bacterial infections potentially include increased morbidity and mortality from the infection itself as well as an increased risk of dissemination of disease. Eradication of persistent infections is difficult, often requiring prolonged or repeated courses of antibiotics. During persistent infections, a population or subpopulation of bacteria exists that is refractory to traditional antibiotics, possibly in a non-replicating or metabolically altered state. This review highlights the clinical significance of persistent infections and discusses different in vitro models used to investigate the altered physiology of bacteria during persistent infections. We specifically focus on recent work establishing increased protection against oxidative stress as a key element of the altered physiologic state across different in vitro models and pathogens. PMID:23563389

An in vivo model of functional and vascularized human brain organoids.

PubMed

Mansour, Abed AlFatah; Gonçalves, J Tiago; Bloyd, Cooper W; Li, Hao; Fernandes, Sarah; Quang, Daphne; Johnston, Stephen; Parylak, Sarah L; Jin, Xin; Gage, Fred H

2018-06-01

Differentiation of human pluripotent stem cells to small brain-like structures known as brain organoids offers an unprecedented opportunity to model human brain development and disease. To provide a vascularized and functional in vivo model of brain organoids, we established a method for transplanting human brain organoids into the adult mouse brain. Organoid grafts showed progressive neuronal differentiation and maturation, gliogenesis, integration of microglia, and growth of axons to multiple regions of the host brain. In vivo two-photon imaging demonstrated functional neuronal networks and blood vessels in the grafts. Finally, in vivo extracellular recording combined with optogenetics revealed intragraft neuronal activity and suggested graft-to-host functional synaptic connectivity. This combination of human neural organoids and an in vivo physiological environment in the animal brain may facilitate disease modeling under physiological conditions.

Helicobacter pylori perturbs iron trafficking in the epithelium to grow on the cell surface.

PubMed

Tan, Shumin; Noto, Jennifer M; Romero-Gallo, Judith; Peek, Richard M; Amieva, Manuel R

2011-05-01

Helicobacter pylori (Hp) injects the CagA effector protein into host epithelial cells and induces growth factor-like signaling, perturbs cell-cell junctions, and alters host cell polarity. This enables Hp to grow as microcolonies adhered to the host cell surface even in conditions that do not support growth of free-swimming bacteria. We hypothesized that CagA alters host cell physiology to allow Hp to obtain specific nutrients from or across the epithelial barrier. Using a polarized epithelium model system, we find that isogenic ΔcagA mutants are defective in cell surface microcolony formation, but exogenous addition of iron to the apical medium partially rescues this defect, suggesting that one of CagA's effects on host cells is to facilitate iron acquisition from the host. Hp adhered to the apical epithelial surface increase basolateral uptake of transferrin and induce its transcytosis in a CagA-dependent manner. Both CagA and VacA contribute to the perturbation of transferrin recycling, since VacA is involved in apical mislocalization of the transferrin receptor to sites of bacterial attachment. To determine if the transferrin recycling pathway is involved in Hp colonization of the cell surface, we silenced transferrin receptor expression during infection. This resulted in a reduced ability of Hp to colonize the polarized epithelium. To test whether CagA is important in promoting iron acquisition in vivo, we compared colonization of Hp in iron-replete vs. iron-deficient Mongolian gerbils. While wild type Hp and ΔcagA mutants colonized iron-replete gerbils at similar levels, ΔcagA mutants are markedly impaired in colonizing iron-deficient gerbils. Our study indicates that CagA and VacA act in concert to usurp the polarized process of host cell iron uptake, allowing Hp to use the cell surface as a replicative niche.

Helicobacter pylori Perturbs Iron Trafficking in the Epithelium to Grow on the Cell Surface

PubMed Central

Tan, Shumin; Noto, Jennifer M.; Romero-Gallo, Judith; Peek, Richard M.; Amieva, Manuel R.

2011-01-01

Helicobacter pylori (Hp) injects the CagA effector protein into host epithelial cells and induces growth factor-like signaling, perturbs cell-cell junctions, and alters host cell polarity. This enables Hp to grow as microcolonies adhered to the host cell surface even in conditions that do not support growth of free-swimming bacteria. We hypothesized that CagA alters host cell physiology to allow Hp to obtain specific nutrients from or across the epithelial barrier. Using a polarized epithelium model system, we find that isogenic ΔcagA mutants are defective in cell surface microcolony formation, but exogenous addition of iron to the apical medium partially rescues this defect, suggesting that one of CagA's effects on host cells is to facilitate iron acquisition from the host. Hp adhered to the apical epithelial surface increase basolateral uptake of transferrin and induce its transcytosis in a CagA-dependent manner. Both CagA and VacA contribute to the perturbation of transferrin recycling, since VacA is involved in apical mislocalization of the transferrin receptor to sites of bacterial attachment. To determine if the transferrin recycling pathway is involved in Hp colonization of the cell surface, we silenced transferrin receptor expression during infection. This resulted in a reduced ability of Hp to colonize the polarized epithelium. To test whether CagA is important in promoting iron acquisition in vivo, we compared colonization of Hp in iron-replete vs. iron-deficient Mongolian gerbils. While wild type Hp and ΔcagA mutants colonized iron-replete gerbils at similar levels, ΔcagA mutants are markedly impaired in colonizing iron-deficient gerbils. Our study indicates that CagA and VacA act in concert to usurp the polarized process of host cell iron uptake, allowing Hp to use the cell surface as a replicative niche. PMID:21589900

From Within Host Dynamics to the Epidemiology of Infectious Disease: Scientific Overview and Challenges

PubMed Central

Gutierrez, Juan B.; Galinski, Mary R.; Cantrell, Stephen; Voit, Eberhard O.

2015-01-01

Since their earliest days, humans have been struggling with infectious diseases. Caused by viruses, bacteria, protozoa, or even higher organisms like worms, these diseases depend critically on numerous intricate interactions between parasites and hosts, and while we have learned much about these interactions, many details are still obscure. It is evident that the combined host-parasite dynamics constitutes a complex system that involves components and processes at multiple scales of time, space, and biological organization. At one end of this hierarchy we know of individual molecules that play crucial roles for the survival of a parasite or for the response and survival of its host. At the other end, one realizes that the spread of infectious diseases by far exceeds specific locales and, due to today's easy travel of hosts carrying a multitude of organisms, can quickly reach global proportions. The community of mathematical modelers has been addressing specific aspects of infectious diseases for a long time. Most of these efforts have focused on one or two select scales of a multi-level disease and used quite different computational approaches. This restriction to a molecular, physiological, or epidemiological level was prudent, as it has produced solid pillars of a foundation from which it might eventually be possible to launch comprehensive, multi-scale modeling efforts that make full use of the recent advances in biology and, in particular, the various high-throughput methodologies accompanying the emerging –omics revolution. This special issue contains contributions from biologists and modelers, most of whom presented and discussed their work at the workshop From within Host Dynamics to the Epidemiology of Infectious Disease, which was held at the Mathematical Biosciences Institute at Ohio State University in April 2014. These contributions highlight some of the forays into a deeper understanding of the dynamics between parasites and their hosts, and the consequences of this dynamics for the spread and treatment of infectious diseases. PMID:26474512

Thermal Shock Induces Host Proteostasis Disruption and Endoplasmic Reticulum Stress in the Model Symbiotic Cnidarian Aiptasia.

PubMed

Oakley, Clinton A; Durand, Elysanne; Wilkinson, Shaun P; Peng, Lifeng; Weis, Virginia M; Grossman, Arthur R; Davy, Simon K

2017-06-02

Coral bleaching has devastating effects on coral survival and reef ecosystem function, but many of the fundamental cellular effects of thermal stress on cnidarian physiology are unclear. We used label-free liquid chromatography-tandem mass spectrometry to compare the effects of rapidly (33.5 °C, 24 h) and gradually (30 and 33.5 °C, 12 days) elevated temperatures on the proteome of the model symbiotic anemone Aiptasia. We identified 2133 proteins in Aiptasia, 136 of which were differentially abundant between treatments. Thermal shock, but not acclimation, resulted in significant abundance changes in 104 proteins, including those involved in protein folding and synthesis, redox homeostasis, and central metabolism. Nineteen abundant structural proteins showed particularly reduced abundance, demonstrating proteostasis disruption and potential protein synthesis inhibition. Heat shock induced antioxidant mechanisms and proteins involved in stabilizing nascent proteins, preventing protein aggregation and degrading damaged proteins, which is indicative of endoplasmic reticulum stress. Host proteostasis disruption occurred before either bleaching or symbiont photoinhibition was detected, suggesting host-derived reactive oxygen species production as the proximate cause of thermal damage. The pronounced abundance changes in endoplasmic reticulum proteins associated with proteostasis and protein turnover indicate that these processes are essential in the cellular response of symbiotic cnidarians to severe thermal stress.

Factor H: A Complement Regulator in Health and Disease, and a Mediator of Cellular Interactions

PubMed Central

Kopp, Anne; Hebecker, Mario; Svobodová, Eliška; Józsi, Mihály

2012-01-01

Complement is an essential part of innate immunity as it participates in host defense against infections, disposal of cellular debris and apoptotic cells, inflammatory processes and modulation of adaptive immune responses. Several soluble and membrane-bound regulators protect the host from the potentially deleterious effects of uncontrolled and misdirected complement activation. Factor H is a major soluble regulator of the alternative complement pathway, but it can also bind to host cells and tissues, protecting them from complement attack. Interactions of factor H with various endogenous ligands, such as pentraxins, extracellular matrix proteins and DNA are important in limiting local complement-mediated inflammation. Impaired regulatory as well as ligand and cell recognition functions of factor H, caused by mutations or autoantibodies, are associated with the kidney diseases: atypical hemolytic uremic syndrome and dense deposit disease and the eye disorder: age-related macular degeneration. In addition, factor H binds to receptors on host cells and is involved in adhesion, phagocytosis and modulation of cell activation. In this review we discuss current concepts on the physiological and pathophysiological roles of factor H in light of new data and recent developments in our understanding of the versatile roles of factor H as an inhibitor of complement activation and inflammation, as well as a mediator of cellular interactions. A detailed knowledge of the functions of factor H in health and disease is expected to unravel novel therapeutic intervention possibilities and to facilitate the development or improvement of therapies. PMID:24970127

The Bacterial Second Messenger Cyclic di-GMP Regulates Brucella Pathogenesis and Leads to Altered Host Immune Response.

PubMed

Khan, Mike; Harms, Jerome S; Marim, Fernanda M; Armon, Leah; Hall, Cherisse L; Liu, Yi-Ping; Banai, Menachem; Oliveira, Sergio C; Splitter, Gary A; Smith, Judith A

2016-12-01

Brucella species are facultative intracellular bacteria that cause brucellosis, a chronic debilitating disease significantly impacting global health and prosperity. Much remains to be learned about how Brucella spp. succeed in sabotaging immune host cells and how Brucella spp. respond to environmental challenges. Multiple types of bacteria employ the prokaryotic second messenger cyclic di-GMP (c-di-GMP) to coordinate responses to shifting environments. To determine the role of c-di-GMP in Brucella physiology and in shaping host-Brucella interactions, we utilized c-di-GMP regulatory enzyme deletion mutants. Our results show that a ΔbpdA phosphodiesterase mutant producing excess c-di-GMP displays marked attenuation in vitro and in vivo during later infections. Although c-di-GMP is known to stimulate the innate sensor STING, surprisingly, the ΔbpdA mutant induced a weaker host immune response than did wild-type Brucella or the low-c-di-GMP guanylate cyclase ΔcgsB mutant. Proteomics analysis revealed that c-di-GMP regulates several processes critical for virulence, including cell wall and biofilm formation, nutrient acquisition, and the type IV secretion system. Finally, ΔbpdA mutants exhibited altered morphology and were hypersensitive to nutrient-limiting conditions. In summary, our results indicate a vital role for c-di-GMP in allowing Brucella to successfully navigate stressful and shifting environments to establish intracellular infection. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The cnidarian origin of the proto-oncogenes NF-κB/STAT and WNT-like oncogenic pathway drives the ctenophores (Review)

PubMed Central

SINKOVICS, JOSEPH G.

2015-01-01

The cell survival pathways of the diploblastic early multicellular eukaryotic hosts contain and operate the molecular machinery resembling those of malignantly transformed individual cells of highly advanced multicellular hosts (including Homo). In the present review, the STAT/NF-κB pathway of the cnidarian Nematostella vectensis is compared with that of human tumors (malignant lymphomas, including Reed-Sternberg cells) pointing out similarities, including possible viral initiation in both cases. In the ctenophore genome and proteome, β-catenin gains intranuclear advantages due to a physiologically weak destructive complex in the cytoplasm, and lack of natural inhibitors (the Dickkopfs). Thus, a scenario similar to what tumor cells initiate and achieve is presented through several constitutive loss-of-function type mutations in the destructive complex and in the elimination of inhibitors. Vice versa, malignantly transformed individual cells of advanced multicellular hosts assume pheno-genotypic resemblance to cells of unicellular or early multicellular hosts, and presumably to their ancient predecessors, by returning to the semblance of immortality and to the resumption of the state of high degree of resistance to physicochemical insults. Human leukemogenic and oncogenic pathways are presented for comparisons. The supreme bioengineers RNA/DNA complex encoded both the malignantly transformed immortal cell and the human cerebral cortex. The former generates molecules for the immortality of cellular life in the Universe. The latter invents the inhibitors of the process in order to gain control over it. PMID:26239915

The cnidarian origin of the proto-oncogenes NF-κB/STAT and WNT-like oncogenic pathway drives the ctenophores (Review).

PubMed

Sinkovics, Joseph G

2015-10-01

The cell survival pathways of the diploblastic early multicellular eukaryotic hosts contain and operate the molecular machinery resembling those of malignantly transformed individual cells of highly advanced multicellular hosts (including Homo). In the present review, the STAT/NF-κB pathway of the cnidarian Nematostella vectensis is compared with that of human tumors (malignant lymphomas, including Reed-Sternberg cells) pointing out similarities, including possible viral initiation in both cases. In the ctenophore genome and proteome, β-catenin gains intranuclear advantages due to a physiologically weak destructive complex in the cytoplasm, and lack of natural inhibitors (the dickkopfs). Thus, a scenario similar to what tumor cells initiate and achieve is presented through several constitutive loss-of-function type mutations in the destructive complex and in the elimination of inhibitors. Vice versa, malignantly transformed individual cells of advanced multicellular hosts assume pheno-genotypic resemblance to cells of unicellular or early multicellular hosts, and presumably to their ancient predecessors, by returning to the semblance of immortality and to the resumption of the state of high degree of resistance to physicochemical insults. Human leukemogenic and oncogenic pathways are presented for comparisons. The supreme bioengineers RNA/DNA complex encoded both the malignantly transformed immortal cell and the human cerebral cortex. The former generates molecules for the immortality of cellular life in the Universe. The latter invents the inhibitors of the process in order to gain control over it.

Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC).

PubMed

Wood, Robin; Morrow, Carl; Barry, Clifton E; Bryden, Wayne A; Call, Charles J; Hickey, Anthony J; Rodes, Charles E; Scriba, Thomas J; Blackburn, Jonathan; Issarow, Chacha; Mulder, Nicola; Woodward, Jeremy; Moosa, Atica; Singh, Vinayak; Mizrahi, Valerie; Warner, Digby F

2016-01-01

Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose physical dimensions suggested the capacity for travel deep into the alveolar spaces of the human lung.

The effects of host size and temperature on the emergence of Echinoparyphium recurvatum cercariae from Lymnaea peregra under natural light conditions.

PubMed

Morley, N J; Adam, M E; Lewis, J W

2010-09-01

The production of cercariae from their snail host is a fundamental component of transmission success in trematodes. The emergence of Echinoparyphium recurvatum (Trematoda: Echinostomatidae) cercariae from Lymnaea peregra was studied under natural sunlight conditions, using naturally infected snails of different sizes (10-17 mm) within a temperature range of 10-29 degrees C. There was a single photoperiodic circadian cycle of emergence with one peak, which correlated with the maximum diffuse sunlight irradiation. At 21 degrees C the daily number of emerging cercariae increased with increasing host snail size, but variations in cercarial emergence did occur between both individual snails and different days. There was only limited evidence of cyclic emergence patterns over a 3-week period, probably due to extensive snail mortality, particularly those in the larger size classes. Very few cercariae emerged in all snail size classes at the lowest temperature studied (10 degrees C), but at increasingly higher temperatures elevated numbers of cercariae emerged, reaching an optimum between 17 and 25 degrees C. Above this range emergence was reduced. At all temperatures more cercariae emerged from larger snails. Analysis of emergence using the Q10 value, a measure of physiological processes over temperature ranges, showed that between 10 and 21 degrees C (approximately 15 degrees C) Q10 values exceeded 100 for all snail size classes, indicating a substantially greater emergence than would be expected for normal physiological rates. From 14 to 25 degrees C (approximately 20 degrees C) cercarial emergence in most snail size classes showed little change in Q10, although in the smallest size class emergence was still substantially greater than the typical Q10 increase expected over this temperature range. At the highest range of 21-29 degrees C (approximately 25 degrees C), Q10 was much reduced. The importance of these results for cercarial emergence under global climate change is discussed.

Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC)

PubMed Central

Wood, Robin; Morrow, Carl; Barry, Clifton E.; Bryden, Wayne A.; Call, Charles J.; Hickey, Anthony J.; Rodes, Charles E.; Scriba, Thomas J.; Blackburn, Jonathan; Issarow, Chacha; Mulder, Nicola; Woodward, Jeremy; Moosa, Atica; Singh, Vinayak; Mizrahi, Valerie; Warner, Digby F.

2016-01-01

Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose physical dimensions suggested the capacity for travel deep into the alveolar spaces of the human lung. PMID:26807816

Clinical metabolomics paves the way towards future healthcare strategies

PubMed Central

Collino, Sebastiano; Martin, François‐Pierre J.; Rezzi, Serge

2013-01-01

Metabolomics is recognized as a powerful top‐down system biological approach to understand genetic‐environment‐health paradigms paving new avenues to identify clinically relevant biomarkers. It is nowadays commonly used in clinical applications shedding new light on physiological regulatory processes of complex mammalian systems with regard to disease aetiology, diagnostic stratification and, potentially, mechanism of action of therapeutic solutions. A key feature of metabolomics lies in its ability to underpin the complex metabolic interactions of the host with its commensal microbial partners providing a new way to define individual and population phenotypes. This review aims at describing recent applications of metabolomics in clinical fields with insight into diseases, diagnostics/monitoring and improvement of homeostatic metabolic regulation. PMID:22348240

Mechanistic Oral Absorption Modeling and Simulation for Formulation Development and Bioequivalence Evaluation: Report of an FDA Public Workshop.

PubMed

Zhang, X; Duan, J; Kesisoglou, F; Novakovic, J; Amidon, G L; Jamei, M; Lukacova, V; Eissing, T; Tsakalozou, E; Zhao, L; Lionberger, R

2017-08-01

On May 19, 2016, the US Food and Drug Administration (FDA) hosted a public workshop, entitled "Mechanistic Oral Absorption Modeling and Simulation for Formulation Development and Bioequivalence Evaluation." The topic of mechanistic oral absorption modeling, which is one of the major applications of physiologically based pharmacokinetic (PBPK) modeling and simulation, focuses on predicting oral absorption by mechanistically integrating gastrointestinal transit, dissolution, and permeation processes, incorporating systems, active pharmaceutical ingredient (API), and the drug product information, into a systemic mathematical whole-body framework. © 2017 The Authors CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

NADPH oxidases: new kids on the block.

PubMed

Geiszt, Miklós

2006-07-15

Reactive oxygen species (ROS) play a pivotal role in many physiological processes including host defense, hormone biosynthesis, fertilization and cellular signaling. Altered production of ROS has been implicated in the development of immunodeficiency, hypothyroidism and cardiovascular pathologies. In the last few years, several enzymes were identified at the molecular level, which are now thought to be responsible for ROS production observed in diverse tissues. These enzymes show a high degree of homology to the phagocytic NADPH oxidase and are now designated the Nox family of NADPH oxidases. This review updates our knowledge on six new members of the Nox family: Nox1, Nox3, Nox4, Nox5, Duox1 and Duox2.

News: Virtual Enzymes

EPA Science Inventory

In biochemical systems a host of “nature’s catalysts” conduct chemical transformations at physiological temperatures, high substrate conversion, high optical activity integrity, and single reactive center substrate changes. All of these traits are highly esteemed in the pursuit o...

Recording axonal conduction to evaluate the integration of pluripotent cell-derived neurons into a neuronal network.

PubMed

Shimba, Kenta; Sakai, Koji; Takayama, Yuzo; Kotani, Kiyoshi; Jimbo, Yasuhiko

2015-10-01

Stem cell transplantation is a promising therapy to treat neurodegenerative disorders, and a number of in vitro models have been developed for studying interactions between grafted neurons and the host neuronal network to promote drug discovery. However, methods capable of evaluating the process by which stem cells integrate into the host neuronal network are lacking. In this study, we applied an axonal conduction-based analysis to a co-culture study of primary and differentiated neurons. Mouse cortical neurons and neuronal cells differentiated from P19 embryonal carcinoma cells, a model for early neural differentiation of pluripotent stem cells, were co-cultured in a microfabricated device. The somata of these cells were separated by the co-culture device, but their axons were able to elongate through microtunnels and then form synaptic contacts. Propagating action potentials were recorded from these axons by microelectrodes embedded at the bottom of the microtunnels and sorted into clusters representing individual axons. While the number of axons of cortical neurons increased until 14 days in vitro and then decreased, those of P19 neurons increased throughout the culture period. Network burst analysis showed that P19 neurons participated in approximately 80% of the bursting activity after 14 days in vitro. Interestingly, the axonal conduction delay of P19 neurons was significantly greater than that of cortical neurons, suggesting that there are some physiological differences in their axons. These results suggest that our method is feasible to evaluate the process by which stem cell-derived neurons integrate into a host neuronal network.

Revisiting the host as a growth medium

PubMed Central

Brown, Stacie A.; Palmer, Kelli L.; Whiteley, Marvin

2011-01-01

The ability of the human body to play host to bacterial pathogens has been studied for more than 200 years. Successful pathogenesis relies on the ability to acquire the nutrients that are necessary for growth and survival, yet relatively little is understood about the in vivo physiology and metabolism of most human pathogens. This Review discusses how in vivo carbon sources can affect disease and highlights the concept that carbon metabolic pathways provide viable targets for antibiotic development. PMID:18679171

Ontogenetic changes in helminth membrane function.

PubMed

Arme, C

1988-01-01

During their life-cycle many parasites experience a wide range of environments including free living and those provided by a variety of intermediate and final hosts. The nutritional requirements of parasites are met by physiological processes adapted to exploit the physicochemical characteristics provided by different hosts. In helminth parasites these adaptations are frequently expressed on the tegumentary surface. As an example of adaptations within the Trematoda, the control of monosaccharide transport in Proterometra sp. is described. Environmental sodium, although not directly involved in the uptake process, nevertheless regulates the expression of transport capabilities. In the Cestoda, the uptake of monosaccharides and amino acids is described for Hymenolepis diminuta. The metacestode of this tapeworm inhabits the blood system of an arthropod, and the adult the gut of a mammal. There are quantitative and qualitative differences in the amino acids and monosaccharides in these two environments and these are reflected in the transport mechanisms exhibited by the two forms of the life-cycle. In Echinococcus granulosus the transfer of amino acids, sugars and macromolecules across the membranes of hydatid cysts and protoscoleces is described. The major difference between these two stages in the life-cycle relates to the ability of hydatid cysts to absorb macromolecules, whereas protoscoleces are impermeable to these compounds. The potential for future work is emphasized.

Biochemical factors modulating female genital sexual arousal physiology.

PubMed

Traish, Abdulmaged M; Botchevar, Ella; Kim, Noel N

2010-09-01

Female genital sexual arousal responses are complex neurophysiological processes consisting of central and peripheral components that occur following sexual stimulation. The peripheral responses in sexual arousal include genital vasocongestion, engorgement and lubrication resulting from a surge of vaginal and clitoral blood flow. These hemodynamic events are mediated by a host of neurotransmitters and vasoactive agents. To discuss the role of various biochemical factors modulating female genital sexual arousal responses. A comprehensive literature review was conducted using the PubMed database and citations were selected, based on topical relevance, and examined for study methodology and major findings. Data from peer-reviewed publications. Adrenergic as well as non-adrenergic non-cholinergic neurotransmitters play an important role in regulating genital physiological responses by mediating vascular and non-vascular smooth muscle contractility. Vasoactive peptides and neuropeptides also modulate genital sexual responses by regulating vascular and non-vascular smooth muscle cells and epithelial function. The endocrine milieu, particularly sex steroid hormones, is critical in the maintenance of tissue structure and function. Reduced levels of estrogens and androgen are associated with dramatic alterations in genital tissue structure, including the nerve network, as well as the response to physiological modulators. Furthermore, estrogen and androgen deficiency is associated with reduced expression of sex steroid receptors and most importantly with attenuated genital blood flow and lubrication in response to pelvic nerve stimulation. This article provides an integrated framework describing the physiological and molecular basis of various pathophysiological conditions associated with female genital sexual arousal dysfunction. © 2010 International Society for Sexual Medicine.

Pathogenic adaptations to host-derived antibacterial copper

PubMed Central

Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

2014-01-01

Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu+) in its reduced form and copper (II) (Cu2+) in its oxidized form under physiologic conditions. Cu+ is significantly more bactericidal than Cu2+ due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it. PMID:24551598

Fitness and virulence of a bacterial endoparasite in an environmentally stressed crustacean host.

PubMed

Coors, Anja; De Meester, Luc

2011-01-01

Host-parasite interactions are shaped by the co-evolutionary arms race of parasite virulence, transmission success as well as host resistance and recovery. The virulence and fitness of parasites may depend on host condition, which is mediated, for instance, by host energy constraints. Here, we investigated to what extent stress imposed by predation threat and environmental pollutants influences host-parasite interactions. We challenged the crustacean host Daphnia magna with the sterilizing bacterial endoparasite Pasteuria ramosa and simultaneously exposed the host to fish kairomones, the pesticide carbaryl or both stressors. While parasite virulence, measured as impact on host mortality and sterilization, increased markedly after short-term pesticide exposure, it was not influenced by predation threat. Parasite fitness, measured in terms of produced transmission stages, decreased both in fish and pesticide treatments. This effect was much stronger under predation threat than carbaryl exposure, and was attributable to reduced somatic growth of the host, presumably resulting in fewer resources for parasite development. While the indirect impact of both stressors on spore loads provides evidence for host condition-dependent parasite fitness, the finding of increased virulence only under carbaryl exposure indicates a stronger physiological impact of the neurotoxic chemical compared with the effect of a non-toxic fish kairomone.

Host specificity in parasitic plants—perspectives from mistletoes

PubMed Central

Okubamichael, Desale Y.; Griffiths, Megan E.; Ward, David

2016-01-01

Host specificity has been investigated for centuries in mistletoes, viruses, insects, parasitoids, lice and flukes, yet it is poorly understood. Reviewing the numerous studies on mistletoe host specificity may contribute to our understanding of these plants and put into context the dynamics at work in root parasitic plants and animal parasites. The mechanisms that determine host specificity in mistletoes are not as well documented and understood as those in other groups of parasites. To rectify this, we synthesized the available literature and analyzed data compiled from herbaria, published monographs and our own field studies in South Africa. As for other groups of parasites, multiple factors influence mistletoe host specificity. Initially, pollination affects gene flow. Subsequently, seed dispersal vectors (birds and marsupials), host abundance and compatibility (genetic, morphological, physiological and chemical), history and environmental conditions affect the interaction of mistletoes and their hosts and determine host specificity. Mistletoe–host network analyses and a geographic mosaic approach combined with long-term monitoring of reciprocal transplant experiments, genetic analyses of confined mistletoe populations and comparative phylogenetic studies could provide further insights to our understanding of host specificity. Some of these approaches have been used to study animal–plant interactions and could be adopted to test and evaluate host specificity in mistletoes at local and larger geographic scales. PMID:27658817

Unique physiology of host-parasite interactions in microsporidia infections.

PubMed

Williams, Bryony A P

2009-11-01

Microsporidia are intracellular parasites of all major animal lineages and have a described diversity of over 1200 species and an actual diversity that is estimated to be much higher. They are important pathogens of mammals, and are now one of the most common infections among immunocompromised humans. Although related to fungi, microsporidia are atypical in genomic biology, cell structure and infection mechanism. Host cell infection involves the rapid expulsion of a polar tube from a dormant spore to pierce the host cell membrane and allow the direct transfer of the spore contents into the host cell cytoplasm. This intimate relationship between parasite and host is unique. It allows the microsporidia to be highly exploitative of the host cell environment and cause such diverse effects as the induction of hypertrophied cells to harbour prolific spore development, host sex ratio distortion and host cell organelle and microtubule reorganization. Genome sequencing has revealed that microsporidia have achieved this high level of parasite sophistication with radically reduced proteomes and with many typical eukaryotic pathways pared-down to what appear to be minimal functional units. These traits make microsporidia intriguing model systems for understanding the extremes of reductive parasite evolution and host cell manipulation.

Influence of temperature on the physiology and virulence of the insect pathogen Serratia sp. Strain SCBI.

PubMed

Petersen, Lauren M; Tisa, Louis S

2012-12-01

The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them.

Influence of Temperature on the Physiology and Virulence of the Insect Pathogen Serratia sp. Strain SCBI

PubMed Central

Petersen, Lauren M.

2012-01-01

The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them. PMID:23042169

From perception to activation: the molecular-genetic and biochemical landscape of disease resistance signaling in plants.

PubMed

Knepper, Caleb; Day, Brad

2010-01-01

More than 60 years ago, H.H. Flor proposed the "Gene-for-Gene" hypothesis, which described the genetic relationship between host plants and pathogens. In the decades that followed Flor's seminal work, our understanding of the plant-pathogen interaction has evolved into a sophisticated model, detailing the molecular genetic and biochemical processes that control host-range, disease resistance signaling and susceptibility. The interaction between plants and microbes is an intimate exchange of signals that has evolved for millennia, resulting in the modification and adaptation of pathogen virulence strategies and host recognition elements. In total, plants have evolved mechanisms to combat the ever-changing landscape of biotic interactions bombarding their environment, while in parallel, plant pathogens have co-evolved mechanisms to sense and adapt to these changes. On average, the typical plant is susceptible to attack by dozens of microbial pathogens, yet in most cases, remains resistant to many of these challenges. The sum of research in our field has revealed that these interactions are regulated by multiple layers of intimately linked signaling networks. As an evolved model of Flor's initial observations, the current paradigm in host-pathogen interactions is that pathogen effector molecules, in large part, drive the recognition, activation and subsequent physiological responses in plants that give rise to resistance and susceptibility. In this Chapter, we will discuss our current understanding of the association between plants and microbial pathogens, detailing the pressures placed on both host and microbe to either maintain disease resistance, or induce susceptibility and disease. From recognition to transcriptional reprogramming, we will review current data and literature that has advanced the classical model of the Gene-for-Gene hypothesis to our current understanding of basal and effector triggered immunity.

Transcriptional and Proteomic Responses to Carbon Starvation in Paracoccidioides

PubMed Central

Lima, Patrícia de Sousa; Casaletti, Luciana; Bailão, Alexandre Melo; de Vasconcelos, Ana Tereza Ribeiro; Fernandes, Gabriel da Rocha; Soares, Célia Maria de Almeida

2014-01-01

Background The genus Paracoccidioides comprises human thermal dimorphic fungi, which cause paracoccidioidomycosis (PCM), an important mycosis in Latin America. Adaptation to environmental conditions is key to fungal survival during human host infection. The adaptability of carbon metabolism is a vital fitness attribute during pathogenesis. Methodology/Principal Findings The fungal pathogen Paracoccidioides spp. is exposed to numerous adverse conditions, such as nutrient deprivation, in the human host. In this study, a comprehensive response of Paracoccidioides, Pb01, under carbon starvation was investigated using high-resolution transcriptomic (RNAseq) and proteomic (NanoUPLC-MSE) approaches. A total of 1,063 transcripts and 421 proteins were differentially regulated, providing a global view of metabolic reprogramming during carbon starvation. The main changes were those related to cells shifting to gluconeogenesis and ethanol production, supported by the degradation of amino acids and fatty acids and by the modulation of the glyoxylate and tricarboxylic cycles. This proposed carbon flow hypothesis was supported by gene and protein expression profiles assessed using qRT-PCR and western blot analysis, respectively, as well as using enzymatic, cell dry weight and fungus-macrophage interaction assays. The carbon source provides a survival advantage to Paracoccidioides inside macrophages. Conclusions/Significance For a complete understanding of the physiological processes in an organism, the integration of approaches addressing different levels of regulation is important. To the best of our knowledge, this report presents the first description of the responses of Paracoccidioides spp. to host-like conditions using large-scale expression approaches. The alternative metabolic pathways that could be adopted by the organism during carbon starvation can be important for a better understanding of the fungal adaptation to the host, because systems for detecting and responding to carbon sources play a major role in adaptation and persistence in the host niche. PMID:24811072

Environmental parasitology: Parasites as accumulation bioindicators in the marine environment

NASA Astrophysics Data System (ADS)

Nachev, Milen; Sures, Bernd

2016-07-01

Parasites can be used as effective monitoring tools in environmental impact studies as they are able to accumulate certain pollutants (e.g. metals) at levels much higher than those of their ambient environment and of free-living sentinels. Thus, they provide valuable information not only about the chemical conditions of their and their hosts' environment but also deliver insights into the biological availability of allochthonous substances. While a large number of different freshwater parasites (mainly acanthocephalans and cestodes) were investigated in terms of pollutant bioaccumulation, studies based on marine host-parasites systems remain scarce. However, available data show that different marine parasite taxa such as nematodes, cestodes and acanthocephalans exhibit also an excellent metal accumulation capacity. The biological availability of metals and their uptake routes in marine biota and parasites differ from those of freshwater organisms. We assume that a large part of metals and other pollutants are also taken up via the digestive system of the host. Therefore, in addition to environmental conditions the physiology of the host also plays an important role for the accumulation process. Additionally, we highlight some advantages in using parasites as accumulation indicators in marine ecosystems. As parasites occur ubiquitously in marine food webs, the monitoring of metals in their tissues can deliver information about the spatial and trophic distribution of pollutants. Accordingly, parasites as indicators offer an ecological assessment on a broader scale, in contrast to established free-living marine indicators, which are mostly benthic invertebrates and therefore limited in habitat distribution. Globally distributed parasite taxa, which are highly abundant in a large number of host species, are suggested as worldwide applicable sentinels.

Forward genetic screening identifies a small molecule that blocks Toxoplasma gondii growth by inhibiting both host- and parasite-encoded kinases.

PubMed

Brown, Kevin M; Suvorova, Elena; Farrell, Andrew; McLain, Aaron; Dittmar, Ashley; Wiley, Graham B; Marth, Gabor; Gaffney, Patrick M; Gubbels, Marc Jan; White, Michael; Blader, Ira J

2014-06-01

The simultaneous targeting of host and pathogen processes represents an untapped approach for the treatment of intracellular infections. Hypoxia-inducible factor-1 (HIF-1) is a host cell transcription factor that is activated by and required for the growth of the intracellular protozoan parasite Toxoplasma gondii at physiological oxygen levels. Parasite activation of HIF-1 is blocked by inhibiting the family of closely related Activin-Like Kinase (ALK) host cell receptors ALK4, ALK5, and ALK7, which was determined in part by use of an ALK4,5,7 inhibitor named SB505124. Besides inhibiting HIF-1 activation, SB505124 also potently blocks parasite replication under normoxic conditions. To determine whether SB505124 inhibition of parasite growth was exclusively due to inhibition of ALK4,5,7 or because the drug inhibited a second kinase, SB505124-resistant parasites were isolated by chemical mutagenesis. Whole-genome sequencing of these mutants revealed mutations in the Toxoplasma MAP kinase, TgMAPK1. Allelic replacement of mutant TgMAPK1 alleles into wild-type parasites was sufficient to confer SB505124 resistance. SB505124 independently impacts TgMAPK1 and ALK4,5,7 signaling since drug resistant parasites could not activate HIF-1 in the presence of SB505124 or grow in HIF-1 deficient cells. In addition, TgMAPK1 kinase activity is inhibited by SB505124. Finally, mice treated with SB505124 had significantly lower tissue burdens following Toxoplasma infection. These data therefore identify SB505124 as a novel small molecule inhibitor that acts by inhibiting two distinct targets, host HIF-1 and TgMAPK1.

Insulin-Like Growth Factor-I as a Candidate Metabolic Biomarker: Military Relevance and Future Directions for Measurement

PubMed Central

Nindl, Bradley C

2009-01-01

Insulin-like growth factor (IGF)-I is a ubiquitous peptide hormone involved in a host of critical physiological processes (e.g., protein synthesis and glucose homeostasis) and has been suggested to be a biomarker reflecting health and metabolic status. In most cases (muscle, bone, tendon, body composition, and cognitive function), elevated IGF-I concentrations are considered beneficial; however, cancer remains a notable exception. While the fact that both increased and decreased IGF-I can be considered reflective of favorable and beneficial health outcomes may appear as a paradox, it is important to emphasize that, in both cases, measured IGF-I concentrations do offer important insight into physiological processes. The effects of military operational field training on the circulating IGF-I system are discussed within the context of novel measurement technologies that (1) are field expedient and (2) provide more meaningful information. Prospective experimental approaches involving physical activity that sample and measure IGF-I in the body's various biocompartments will provide greater insight into the complex role that IGF-I possesses. Minimally invasive technologies that are field expedient, cost-effective, and allow for continuous and real-time feedback will have the greatest likelihood of being adapted and used in military environments. PMID:20144370

Disrupting the Amblyomma americanum (L.) CD147 receptor homolog prevents ticks from feeding to repletion and blocks spontaneous detachment of ticks from their host.

PubMed

Mulenga, Albert; Khumthong, Rabuesak

2010-07-01

The CD147 receptor is a cell-surface glycoprotein in the IgG family that plays pivotal roles in intercellular interactions involved with numerous physiological and pathological processes such as extracellular matrix remodeling. We previously found an Amblyomma americanum (Aam) tick CD147 receptor homolog among genes that were up regulated in response to tick feeding stimuli. This study characterizes an AamCD147 receptor protein that is 72-83% conserved in other tick species and possess characteristic CD147 receptor sequence features: an extracellular (EC) region containing two IgG domains, a transmembrane and the cytoplasmic domains. Likewise, the AamCD147 EC domain folds into secondary structures that are consistent to the human homolog: an amino-terminus beta-barrel that is linked to 2-carboxy-terminus beta-sheets with consensus disulfide bonds conserved in each of the 2 domains. CD147 receptor signaling and regulatory mechanisms are putatively conserved in ticks as revealed by in silico analysis that show presence in the tick genome of CD147 receptor signaling protein homologs, cyclophilin (CyP) A and B, and chaperones that transport it to the plasma membrane, caveolin-1 and CyP60. The AamCD147 receptor has a dichotomous expression pattern of where it is up regulated in response to feeding in the salivary gland but remains constant at the midgut and ovary levels suggesting that it may regulate different functions in different tick organs. We speculate that biological functions of the AamCD147 receptor are essential to tick feeding success as revealed by RNAi-mediated silencing that caused ticks to obtain smaller blood meals, of which approximately 69% were below threshold to trigger spontaneous detachment of ticks from the host. These ticks showed unusual cuticle tenderness and assumed a reddish coloration, a phenomenon that has been attributed to tick midgut damage allowing red blood cells to leak into tick hemolymph. On the basis of the CD147 receptor being linked to tissue growth regulation in mammals, we speculate that silencing of the AamCD147 receptor blocked progression of the tick intermolt growth, a process that precedes tick engorgement and their spontaneous detachment of from the host to end feeding. The results are discussed in context of advances in tick molecular physiology. 2010 Elsevier Ltd. All rights reserved.

Human organoid cultures: transformative new tools for human virus studies.

PubMed

Ramani, Sasirekha; Crawford, Sue E; Blutt, Sarah E; Estes, Mary K

2018-04-01

Studies of human infectious diseases have been limited by the paucity of functional models that mimic normal human physiology and pathophysiology. Recent advances in the development of multicellular, physiologically active organotypic cultures produced from embryonic and pluripotent stem cells, as well as from stem cells isolated from biopsies and surgical specimens are allowing unprecedented new studies and discoveries about host-microbe interactions. Here, we summarize recent developments in the use of organoids for studying human viral pathogens, including intestinal infections with human rotavirus, norovirus, enteroviruses and adenoviruses (intestinal organoids and enteroids), neuronal infections with Zika virus (cerebral organoids) and respiratory infections with respiratory syncytial virus in (lung bud organoids). Biologic discovery of host-specific genetic and epigenetic factors affecting infection, and responses to infection that lead to disease are possible with the use of organoid cultures. Continued development to increase the complexity of these cultures by including components of the normal host tissue microenvironment such as immune cells, blood vessels and microbiome, will facilitate studies on human viral pathogenesis, and advance the development of platforms for pre-clinical evaluation of vaccines, antivirals and therapeutics. Copyright © 2018 Elsevier B.V. All rights reserved.

Microbiome-mediated bile acid modification: Role in intestinal drug absorption and metabolism.

PubMed

Enright, Elaine F; Griffin, Brendan T; Gahan, Cormac G M; Joyce, Susan A

2018-04-13

Once regarded obscure and underappreciated, the gut microbiota (the microbial communities colonizing the gastrointestinal tract) is gaining recognition as an influencer of many aspects of human health. Also increasingly apparent is the breadth of interindividual variation in these co-evolved microbial-gut associations, presenting novel quests to explore implications for disease and therapeutic response. In this respect, the unearthing of the drug-metabolizing capacity of the microbiota has provided impetus for the integration of microbiological and pharmacological research. This review considers a potential mechanism, 'microbial bile acid metabolism', by which the intricate interplay between the host and gut bacteria may influence drug pharmacokinetics. Bile salts traditionally regarded as biological surfactants, synthesized by the host and biotransformed by gut bacteria, are now also recognized as signalling molecules that affect diverse physiological processes. Accumulating data indicate that bile salts are not equivalent with respect to their physicochemical properties, micellar solubilization capacities for poorly water-soluble drugs, crystallization inhibition tendencies nor potencies for bile acid receptor activation. Herein, the origin, physicochemical properties, physiological functions, plasticity and pharmaceutical significance of the human bile acid pool are discussed. Microbial dependant differences in the composition of the human bile acid pool, simulated intestinal media and commonly used preclinical species is highlighted to better understand in vivo performance predictiveness. While the precise impact of an altered gut microbiome, and consequently bile acid pool, in the biopharmaceutical setting remains largely elusive, the objective of this article is to aid knowledge acquisition through a detailed review of the literature. Copyright © 2018 Elsevier Ltd. All rights reserved.

A new bioadhesive material from fish parasite Neobenedenia girellae.

PubMed

Maffioli, Elisa; Nonnis, Simona; Polo, Nerea Cuevas; Negri, Armando; Forcella, Matilde; Fusi, Paola; Galli, Paolo; Tedeschi, Gabriella

2014-10-14

The purpose of the work was to identify the proteins present in the adhesive material of the capsalid Neobenedenia girellae by a proteomic approach based on de novo sequencing and data base search to overcome the lack of information concerning the genome of these parasites. Glandular secretions were obtained by a new method, set up in our laboratory, which allowed collecting a small amount of secretion without any contamination from other tissues either from the parasites as well as from the skin of the host. The proteomic analysis reveals that the adhesive is mainly composed of cytoskeletal proteins (actin, keratin and tubulin) but contains also ATP-synthase, 78 kDa glucose regulated protein and albumin. This paper reports for the first time the characterization of a novel bioadhesive material used by capsalid parasites to adhere to fish. Such information broadens our knowledge of the molecular mechanisms involved in adhesiveness of parasites to hosts. Moreover, it offers new clues in understanding the mechanism of stickiness and adhesion of cytoskeleton components, often involved in both physiological and pathological processes, including neurodegenerative diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Fungal dimorphism: the switch from hyphae to yeast is a specialized morphogenetic adaptation allowing colonization of a host.

PubMed

Boyce, Kylie J; Andrianopoulos, Alex

2015-11-01

The ability of pathogenic fungi to switch between a multicellular hyphal and unicellular yeast growth form is a tightly regulated process known as dimorphic switching. Dimorphic switching requires the fungus to sense and respond to the host environment and is essential for pathogenicity. This review will focus on the role of dimorphism in fungi commonly called thermally dimorphic fungi, which switch to a yeast growth form during infection. This group of phylogenetically diverse ascomycetes includes Talaromyces marneffei (recently renamed from Penicillium marneffei), Blastomyces dermatitidis (teleomorph Ajellomyces dermatitidis), Coccidioides species (C. immitis and C. posadasii), Histoplasma capsulatum (teleomorph Ajellomyces capsulatum), Paracoccidioides species (P. brasiliensis and P. lutzii) and Sporothrix schenckii (teleomorph Ophiostoma schenckii). This review will explore both the signalling pathways regulating the morphological transition and the transcriptional responses necessary for intracellular growth. The physiological requirements of yeast cells during infection will also be discussed, highlighting recent advances in the understanding of the role of iron and calcium acquisition during infection. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cyclic Dinucleotides in Oral Bacteria and in Oral Biofilms.

PubMed

Gürsoy, Ulvi K; Gürsoy, Mervi; Könönen, Eija; Sintim, Herman O

2017-01-01

Oral cavity acts as a reservoir of bacterial pathogens for systemic infections and several oral microorganisms have been linked to systemic diseases. Quorum sensing and cyclic dinucleotides, two "decision-making" signaling systems, communicate to regulate physiological process in bacteria. Discovery of cyclic dinucleotides has a long history, but the progress in our understanding of how cyclic dinucleotides regulate bacterial lifestyle is relatively new. Oral microorganisms form some of the most intricate biofilms, yet c-di-GMP, and c-di-AMP signaling have been rarely studied in oral biofilms. Recent studies demonstrated that, with the aid of bacterial messenger molecules and their analogs, it is possible to activate host innate and adaptive immune responses and epithelial integrity with a dose that is relevant to inhibit bacterial virulence mechanisms, such as fimbriae and exopolysaccharide production, biofilm formation, and host cell invasion. The aim of this perspective article is to present available information on cyclic dinucleotides in oral bacteria and in oral biofilms. Moreover, technologies that can be used to detect cyclic dinucleotides in oral biofilms are described. Finally, directions for future research are highlighted.

Function of the CRISPR-Cas System of the Human Pathogen Clostridium difficile

PubMed Central

Boudry, Pierre; Semenova, Ekaterina; Monot, Marc; Datsenko, Kirill A.; Lopatina, Anna; Sekulovic, Ognjen; Ospina-Bedoya, Maicol; Fortier, Louis-Charles; Severinov, Konstantin; Dupuy, Bruno

2015-01-01

ABSTRACT Clostridium difficile is the cause of most frequently occurring nosocomial diarrhea worldwide. As an enteropathogen, C. difficile must be exposed to multiple exogenous genetic elements in bacteriophage-rich gut communities. CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems allow bacteria to adapt to foreign genetic invaders. Our recent data revealed active expression and processing of CRISPR RNAs from multiple type I-B CRISPR arrays in C. difficile reference strain 630. Here, we demonstrate active expression of CRISPR arrays in strain R20291, an epidemic C. difficile strain. Through genome sequencing and host range analysis of several new C. difficile phages and plasmid conjugation experiments, we provide evidence of defensive function of the CRISPR-Cas system in both C. difficile strains. We further demonstrate that C. difficile Cas proteins are capable of interference in a heterologous host, Escherichia coli. These data set the stage for mechanistic and physiological analyses of CRISPR-Cas-mediated interactions of important global human pathogen with its genetic parasites. PMID:26330515

Plant Proteomics and Peptidomics in Host-Pathogen Interactions: The Weapons Used by Each Side.

PubMed

Silva, Fabiana Aparecida Cavalcante; de Sousa Oliveira, Melquisedec; de Souza, Juliana Maria; Martins, Paulo Geovani Silva; Pestana-Calsa, Maria Clara; Junior, Tercilio Calsa

2017-01-01

Environmental biotic stress factors act continuously on plants, through multiple molecular interactions that eventually lead to the establishment and progress of symbiotic or pathogenic complex interactions. Proteins and peptides play noteworthy roles in such biological processes, usually being the main effectors since the initial recognizing and elicitor functions until the following transduction, gene regulation and physiological responses activities. Ranging from specific regulators to direct antimicrobial agents, plant or pathogen proteins and peptides comprise the arsenal available to each side in this biological war, resulting from the genetic coding potential inherited by each one. Post-translational research tools have widely contributed with valuable information on how the plant proteome works to achieve, maintain and adjust plant immunity in order to properly cope with the challenging pathogenic derived proteomes. These key proteins and peptides have great biotechnological potential since they represent distinctive features of each pathogen group (fungi, bacteria, viruses and other) in response to molecules of defense of host plants. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Altered microRNA regulation of short chain fatty acid receptors in the hypertensive kidney is normalized with hydrogen sulfide supplementation.

PubMed

Weber, Gregory J; Foster, Jaleyea; Pushpakumar, Sathnur B; Sen, Utpal

2018-06-15

Hypertension affects nearly one third of the adult US population and is a significant risk factor for chronic kidney disease (CKD). An expanding body of recent studies indicates that gut microbiome has crucial roles in regulating physiological processes through, among other mechanisms, one mode of short chain fatty acids (SCFA) and their target receptors. In addition, these SCFA receptors are potential targets of regulation by host miRNAs, however, the mechanisms through which this occurs is not clearly defined. Hydrogen sulfide (H 2 S) is an important gasotransmitter involved in multiple physiological processes and is known to alleviate adverse effects of hypertension such as reducing inflammation in the kidney. To determine the role of host microRNAs in regulating short chain fatty acid receptors in the kidney as well as the gut, C57BL/6J wild-type mice were treated with or without Ang-II and H 2 S donor GYY4137 (GYY) for 4 weeks to assess whether GYY would normalize adverse effects observed in hypertensive mice and whether this was in part due to altered gut microbiome composition. We observed several changes of SCFA receptors, including Olfr78, Gpr41/43 and predicted microRNA regulators in the kidney among the different treatments. Increased expression of inflammatory markers Il6 and Rorc2, along with Tgfβ, were found in the hypertensive kidney. The glomerular filtration rate (GFR) was improved in mice treated with Ang-II + GYY compared with Ang-II only, indicating improved kidney function. The Erysipelotrichia class of bacteria, linked with high fat diets, was enriched in hypertensive animals but reduced with GYY supplementation. These data point towards a role for miRNA regulation of SCFA receptors in hypertensive kidney and are normalized by H 2 S supplementation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Use of ex vivo and in vitro cultures of the human respiratory tract to study the tropism and host responses of highly pathogenic avian influenza A (H5N1) and other influenza viruses.

PubMed

Chan, Renee W Y; Chan, Michael C W; Nicholls, John M; Malik Peiris, J S

2013-12-05

The tropism of influenza viruses for the human respiratory tract is a key determinant of host-range, and consequently, of pathogenesis and transmission. Insights can be obtained from clinical and autopsy studies of human disease and relevant animal models. Ex vivo cultures of the human respiratory tract and in vitro cultures of primary human cells can provide complementary information provided they are physiologically comparable in relevant characteristics to human tissues in vivo, e.g. virus receptor distribution, state of differentiation. We review different experimental models for their physiological relevance and summarize available data using these cultures in relation to highly pathogenic avian influenza H5N1, in comparison where relevant, with other influenza viruses. Transformed continuous cell-lines often differ in important ways to the corresponding tissues in vivo. The state of differentiation of primary human cells (respiratory epithelium, macrophages) can markedly affect virus tropism and host responses. Ex vivo cultures of human respiratory tissues provide a close resemblance to tissues in vivo and may be used to risk assess animal viruses for pandemic threat. Physiological factors (age, inflammation) can markedly affect virus receptor expression and virus tropism. Taken together with data from clinical studies on infected humans and relevant animal models, data from ex vivo and in vitro cultures of human tissues and cells can provide insights into virus transmission and pathogenesis and may provide understanding that leads to novel therapeutic interventions. Copyright © 2013 Elsevier B.V. All rights reserved.

Physiological response of Pichia pastoris GS115 to methanol-induced high level production of the Hepatitis B surface antigen: catabolic adaptation, stress responses, and autophagic processes

PubMed Central

2012-01-01

Background Pichia pastoris is an established eukaryotic host for the production of recombinant proteins. Most often, protein production is under the control of the strong methanol-inducible aox1 promoter. However, detailed information about the physiological alterations in P. pastoris accompanying the shift from growth on glycerol to methanol-induced protein production under industrial relevant conditions is missing. Here, we provide an analysis of the physiological response of P. pastoris GS115 to methanol-induced high-level production of the Hepatitis B virus surface antigen (HBsAg). High product titers and the retention of the protein in the endoplasmic reticulum (ER) are supposedly of major impact on the host physiology. For a more detailed understanding of the cellular response to methanol-induced HBsAg production, the time-dependent changes in the yeast proteome and ultrastructural cell morphology were analyzed during the production process. Results The shift from growth on glycerol to growth and HBsAg production on methanol was accompanied by a drastic change in the yeast proteome. In particular, enzymes from the methanol dissimilation pathway started to dominate the proteome while enzymes from the methanol assimilation pathway, e.g. the transketolase DAS1, increased only moderately. The majority of methanol was metabolized via the energy generating dissimilatory pathway leading to a corresponding increase in mitochondrial size and numbers. The methanol-metabolism related generation of reactive oxygen species induced a pronounced oxidative stress response (e.g. strong increase of the peroxiredoxin PMP20). Moreover, the accumulation of HBsAg in the ER resulted in the induction of the unfolded protein response (e.g. strong increase of the ER-resident disulfide isomerase, PDI) and the ER associated degradation (ERAD) pathway (e.g. increase of two cytosolic chaperones and members of the AAA ATPase superfamily) indicating that potential degradation of HBsAg could proceed via the ERAD pathway and through the proteasome. However, the amount of HBsAg did not show any significant decline during the cultivation revealing its general protection from proteolytic degradation. During the methanol fed-batch phase, induction of vacuolar proteases (e.g. strong increase of APR1) and constitutive autophagic processes were observed. Vacuolar enclosures were mainly found around peroxisomes and not close to HBsAg deposits and, thus, were most likely provoked by peroxisomal components damaged by reactive oxygen species generated by methanol oxidation. Conclusions In the methanol fed-batch phase P. pastoris is exposed to dual stress; stress resulting from methanol degradation and stress resulting from the production of the recombinant protein leading to the induction of oxidative stress and unfolded protein response pathways, respectively. Finally, the modest increase of methanol assimilatory enzymes compared to the strong increase of methanol dissimilatory enzymes suggests here a potential to increase methanol incorporation into biomass/product through metabolic enhancement of the methanol assimilatory pathway. PMID:22873405

Quantifying host potentials: indexing postharvest fresh fruits for spotted wing Drosophila, Drosophila suzukii.

PubMed

Bellamy, David E; Sisterson, Mark S; Walse, Spencer S

2013-01-01

Novel methodology is presented for indexing the relative potential of hosts to function as resources. A Host Potential Index (HPI) was developed as a practical framework to express relative host potential based on combining results from one or more independent studies, such as those examining host selection, utilization, and physiological development of the organism resourcing the host. Several aspects of the HPI are addressed including: 1) model derivation; 2) influence of experimental design on establishing host rankings for a study type (no choice, two-choice, and multiple-choice); and, 3) variable selection and weighting associated with combining multiple studies. To demonstrate application of the HPI, results from the interactions of spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), with seven "reported" hosts (blackberries, blueberries, sweet cherries, table grapes, peaches, raspberries, and strawberries) in a postharvest scenario were analyzed. Four aspects of SWD-host interaction were examined: attraction to host volatiles; population-level oviposition performance; individual-level oviposition performance; and key developmental factors. Application of HPI methodology indicated that raspberries ( (mean)HPIvaried  = 301.9±8.39; rank 1 of 7) have the greatest potential to serve as a postharvest host for SWD relative to the other fruit hosts, with grapes ( (mean)HPIvaried  = 232.4±3.21; rank 7 of 7) having the least potential.

Quantifying Host Potentials: Indexing Postharvest Fresh Fruits for Spotted Wing Drosophila, Drosophila suzukii

PubMed Central

Bellamy, David E.; Sisterson, Mark S.; Walse, Spencer S.

2013-01-01

Novel methodology is presented for indexing the relative potential of hosts to function as resources. A Host Potential Index (HPI) was developed as a practical framework to express relative host potential based on combining results from one or more independent studies, such as those examining host selection, utilization, and physiological development of the organism resourcing the host. Several aspects of the HPI are addressed including: 1) model derivation; 2) influence of experimental design on establishing host rankings for a study type (no choice, two-choice, and multiple-choice); and, 3) variable selection and weighting associated with combining multiple studies. To demonstrate application of the HPI, results from the interactions of spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), with seven “reported” hosts (blackberries, blueberries, sweet cherries, table grapes, peaches, raspberries, and strawberries) in a postharvest scenario were analyzed. Four aspects of SWD-host interaction were examined: attraction to host volatiles; population-level oviposition performance; individual-level oviposition performance; and key developmental factors. Application of HPI methodology indicated that raspberries (meanHPIvaried = 301.9±8.39; rank 1 of 7) have the greatest potential to serve as a postharvest host for SWD relative to the other fruit hosts, with grapes (meanHPIvaried = 232.4±3.21; rank 7 of 7) having the least potential. PMID:23593439

Host and Environmental Specificity in Bacterial Communities Associated to Two Highly Invasive Marine Species (Genus Asparagopsis)

PubMed Central

Aires, Tânia; Serrão, Ester A.; Engelen, Aschwin H.

2016-01-01

As habitats change due to global and local pressures, population resilience, and adaptive processes depend not only on their gene pools but also on their associated bacteria communities. The hologenome can play a determinant role in adaptive evolution of higher organisms that rely on their bacterial associates for vital processes. In this study, we focus on the associated bacteria of the two most invasive seaweeds in southwest Iberia (coastal mainland) and nearby offshore Atlantic islands, Asparagopsis taxiformis and Asparagopsis armata. Bacterial communities were characterized using 16S rRNA barcoding through 454 next generation sequencing and exploratory shotgun metagenomics to provide functional insights and a backbone for future functional studies. The bacterial community composition was clearly different between the two species A. taxiformis and A. armata and between continental and island habitats. The latter was mainly due to higher abundances of Acidimicrobiales, Sphingomonadales, Xanthomonadales, Myxococcales, and Alteromonadales on the continent. Metabolic assignments for these groups contained a higher number of reads in functions related to oxidative stress and resistance to toxic compounds, more precisely heavy metals. These results are in agreement with their usual association with hydrocarbon degradation and heavy-metals detoxification. In contrast, A. taxiformis from islands contained more bacteria related to oligotrophic environments which might putatively play a role in mineralization of dissolved organic matter. The higher number of functional assignments found in the metagenomes of A. taxiformis collected from Cape Verde Islands suggest a higher contribution of bacteria to compensate nutrient limitation in oligotrophic environments. Our results show that Asparagopsis-associated bacterial communities have host-specificity and are modulated by environmental conditions. Whether this environmental effect reflects the host's selective requirements or the locally available bacteria remains to be addressed. However, the known functional capacities of these bacterial communities indicate their potential for eco-physiological functions that could be valuable for the host fitness. PMID:27148239

Multidrug Efflux Systems in Microaerobic and Anaerobic Bacteria

PubMed Central

Xu, Zeling; Yan, Aixin

2015-01-01

Active drug efflux constitutes an important mechanism of antibiotic and multidrug resistance in bacteria. Understanding the distribution, expression, and physiological functions of multidrug efflux pumps, especially under physiologically and clinically relevant conditions of the pathogens, is the key to combat drug resistance. In animal hosts, most wounded, infected and inflamed tissues display low oxygen tensions. In this article, we summarize research development on multidrug efflux pumps in the medicinally relevant microaerobic and anaerobic pathogens and their implications in the effort to combat drug-resistant infections. PMID:27025630

Co-culture of Gastric Organoids and Immortalized Stomach Mesenchymal Cells.

PubMed

Bertaux-Skeirik, Nina; Centeno, Jomaris; Feng, Rui; Schumacher, Michael A; Shivdasani, Ramesh A; Zavros, Yana

2016-01-01

Three-dimensional primary epithelial-derived gastric organoids have recently been established as an important tool to study gastric development, physiology, and disease. Specifically, mouse-derived fundic gastric organoids (mFGOs) co-cultured with Immortalized Stomach Mesenchymal Cells (ISMCs) reflect expression patterns of mature fundic cell types seen in vivo, thus allowing for long-term in vitro studies of gastric epithelial cell physiology, regeneration, and bacterial-host interactions. Here, we describe the development and culture of mFGOs, co-cultured with ISMCs.

Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae.

PubMed

Fléchard, Maud; Gilot, Philippe

2014-07-01

We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB-lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the 'success' of the infectious process. © 2014 The Authors.

Deletion of pilA, a Minor Pilin-Like Gene, from Xanthomonas citri subsp. citri Influences Bacterial Physiology and Pathogenesis.

PubMed

Petrocelli, Silvana; Arana, Maite R; Cabrini, Marcela N; Casabuono, Adriana C; Moyano, Laura; Beltramino, Matías; Moreira, Leandro M; Couto, Alicia S; Orellano, Elena G

2016-12-01

Type IV pili (Tfp) are widely distributed adhesins of bacterial surfaces. In plant pathogenic bacteria, Tfp are involved in host colonization and pathogenesis. Xanthomonas citri subsp. citri (Xcc) is the phytopathogen responsible for citrus canker disease. In this work, three Tfp structural genes, fimA, fimA1, and pilA from Xcc were studied. A pilA mutant strain from Xcc (XccΔpilA) was constructed and differences in physiological features, such as motilities, adhesion, and biofilm formation, were observed. A structural study of the purified Tfp fractions from Xcc wild-type and Xcc∆pilA showed that pilins are glycosylated in both strains and that FimA and FimA1 are the main structural components of the pili. Furthermore, smaller lesion symptoms and reduced bacterial growth were produced by Xcc∆pilA in orange plants compared to the wild-type strain. These results indicate that the minor pilin-like gene, pilA, is involved in Tfp performance during the infection process.

Luminescent sensing and imaging of oxygen: Fierce competition to the Clark electrode

PubMed Central

2015-01-01

Luminescence‐based sensing schemes for oxygen have experienced a fast growth and are in the process of replacing the Clark electrode in many fields. Unlike electrodes, sensing is not limited to point measurements via fiber optic microsensors, but includes additional features such as planar sensing, imaging, and intracellular assays using nanosized sensor particles. In this essay, I review and discuss the essentials of (i) common solid‐state sensor approaches based on the use of luminescent indicator dyes and host polymers; (ii) fiber optic and planar sensing schemes; (iii) nanoparticle‐based intracellular sensing; and (iv) common spectroscopies. Optical sensors are also capable of multiple simultaneous sensing (such as O2 and temperature). Sensors for O2 are produced nowadays in large quantities in industry. Fields of application include sensing of O2 in plant and animal physiology, in clinical chemistry, in marine sciences, in the chemical industry and in process biotechnology. PMID:26113255

Spatial Segregation and Aggregation of Ectomycorrhizal and Root-Endophytic Fungi in the Seedlings of Two Quercus Species

PubMed Central

Yamamoto, Satoshi; Sato, Hirotoshi; Tanabe, Akifumi S.; Hidaka, Amane; Kadowaki, Kohmei; Toju, Hirokazu

2014-01-01

Diverse clades of mycorrhizal and endophytic fungi are potentially involved in competitive or facilitative interactions within host-plant roots. We investigated the potential consequences of these ecological interactions on the assembly process of root-associated fungi by examining the co-occurrence of pairs of fungi in host-plant individuals. Based on massively-parallel pyrosequencing, we analyzed the root-associated fungal community composition for each of the 249 Quercus serrata and 188 Quercus glauca seedlings sampled in a warm-temperate secondary forest in Japan. Pairs of fungi that co-occurred more or less often than expected by chance were identified based on randomization tests. The pyrosequencing analysis revealed that not only ectomycorrhizal fungi but also endophytic fungi were common in the root-associated fungal community. Intriguingly, specific pairs of these ectomycorrhizal and endophytic fungi showed spatially aggregated patterns, suggesting the existence of facilitative interactions between fungi in different functional groups. Due to the large number of fungal pairs examined, many of the observed aggregated/segregated patterns with very low P values (e.g., < 0.005) turned non-significant after the application of a multiple comparison method. However, our overall results imply that the community structures of ectomycorrhizal and endophytic fungi could influence each other through interspecific competitive/facilitative interactions in root. To test the potential of host-plants' control of fungus–fungus ecological interactions in roots, we further examined whether the aggregated/segregated patterns could vary depending on the identity of host plant species. Potentially due to the physiological properties shared between the congeneric host plant species, the sign of hosts' control was not detected in the present study. The pyrosequencing-based randomization analyses shown in this study provide a platform of the high-throughput investigation of fungus–fungus interactions in plant root systems. PMID:24801150

Compartmentalized and systemic control of tissue immunity by commensals

PubMed Central

Belkaid, Yasmine; Naik, Shruti

2013-01-01

The body is composed of various tissue microenvironments with finely tuned local immunosurveillance systems, many of which are in close apposition with distinct commensal niches. Mammals have formed an evolutionary partnership with the microbiota that is critical for metabolism, tissue development and host defense. Despite our growing understanding of the impact of this host-microbe alliance on immunity in the gastrointestinal tract, the extent to which individual microenvironments are controlled by resident microbiota remains unclear. In this Perspective we discuss how resident commensals outside the gastrointestinal tract can control unique physiological niches and the potential implications of the dialog between these commensals and the host for the establishment of immune homeostasis, protective responses and tissue pathology. PMID:23778791

Hypothesis: leukocyte endogenous mediator/endogenous pyrogen/lymphocyte-activating factor modulates the development of nonspecific and specific immunity and affects nutritional status.

PubMed

Powanda, M C; Beisel, W R

1982-04-01

We postulate that leukocyte endogenous mediator/endogenous pyrogen/lymphocyte-activating factor (LEM/EP/LAF) integrates the host's nonspecific and specific immune responses to infection by virtue of the panoply of physiological and metabolic activities it is capable of eliciting. The alterations in systemic metabolism modulated by LEM/EP/LAF, although apparently of value to the host in the defense against infection and the repair of tissue damage, result in negative nutrient balances. Severe infections, alone or in conjunction with injury, may result in malnutrition unless the patient is adequately nourished. Preexisting nutritional deficits can compromise host resistance to infection, in part by preventing production of LEM/EP/LAF. Additional studies of the sequelae of LEM/EP/LAF action and effects of nutrition on host resistance to infection appear warranted.

[Dynamics of parasite communities in an age series of Arctic Cisco Coregonus migratorius (Georgi, 1775)].

PubMed

Dugarov, Zh N; Pronin, N M

2013-01-01

Parasite communities of Arctic cisco from Chivyrkui Bay of Lake Baikal have been analyzed at levels of a host individual (infracommunity), a individual age group of a host-(assemblages of infracommunities), and a host population (component community). Significant positive correlations of parameters of species richness (number of parasite species, Margalef and Menhinick indices) with the age of Arctic cisco were recorded only at the level of parasite inffacommunities. The absence of linear positive correlations between the parameters of species richness and the age of Arctic cisco at the level of assemblages of parasite infracommunities were revealed for the first time for fish of Lake Baikal. The peculiarity of the dynamics of parasite communities of. Arctic cisco is determined by specific features of the host physiology and ecology, primarily by the age dynamics of the feeding spectrum.

Light emission mechanism of mixed host organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Song, Wook; Lee, Jun Yeob

2015-03-01

Light emission mechanism of organic light-emitting diodes with a mixed host emitting layer was studied using an exciplex type mixed host and an exciplex free mixed host. Monitoring of the current density and luminance of the two type mixed host devices revealed that the light emission process of the exciplex type mixed host was dominated by energy transfer, while the light emission of the exciplex free mixed host was controlled by charge trapping. Mixed host composition was also critical to the light emission mechanism, and the contribution of the energy transfer process was maximized at 50:50 mixed host composition. Therefore, it was possible to manage the light emission process of the mixed host devices by managing the mixed host composition.

Host specificity in parasitic plants-perspectives from mistletoes.

PubMed

Okubamichael, Desale Y; Griffiths, Megan E; Ward, David

2016-01-01

Host specificity has been investigated for centuries in mistletoes, viruses, insects, parasitoids, lice and flukes, yet it is poorly understood. Reviewing the numerous studies on mistletoe host specificity may contribute to our understanding of these plants and put into context the dynamics at work in root parasitic plants and animal parasites. The mechanisms that determine host specificity in mistletoes are not as well documented and understood as those in other groups of parasites. To rectify this, we synthesized the available literature and analyzed data compiled from herbaria, published monographs and our own field studies in South Africa. As for other groups of parasites, multiple factors influence mistletoe host specificity. Initially, pollination affects gene flow. Subsequently, seed dispersal vectors (birds and marsupials), host abundance and compatibility (genetic, morphological, physiological and chemical), history and environmental conditions affect the interaction of mistletoes and their hosts and determine host specificity. Mistletoe-host network analyses and a geographic mosaic approach combined with long-term monitoring of reciprocal transplant experiments, genetic analyses of confined mistletoe populations and comparative phylogenetic studies could provide further insights to our understanding of host specificity. Some of these approaches have been used to study animal-plant interactions and could be adopted to test and evaluate host specificity in mistletoes at local and larger geographic scales. © The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

Chronic Nosema ceranae infection inflicts comprehensive and persistent immunosuppression and accelerated lipid loss in host Apis mellifera honey bees.

PubMed

Li, Wenfeng; Chen, Yanping; Cook, Steven C

2018-05-01

Nosema ceranae is an intracellular microsporidian parasite of the Asian honey bee Apis cerana and the European honey bee Apis mellifera. Until relatively recently, A. mellifera honey bees were naïve to N. ceranae infection. Symptoms of nosemosis, or Nosema disease, in the infected hosts include immunosuppression, damage to gut epithelium, nutrient and energetic stress, precocious foraging and reduced longevity of infected bees. Links remain unclear between immunosuppression, the symptoms of nutrient and energetic stress, and precocious foraging behavior of hosts. To clarify physiological connections, we inoculated newly emerged A. mellifera adult workers with N. ceranae spores, and over 21 days post inoculation (21 days pi), gauged infection intensity and quantified expression of genes representing two innate immune pathways, Toll and Imd. Additionally, we measured each host's whole-body protein, lipids, carbohydrates and quantified respirometric and activity levels. Results show sustained suppression of genes of both humorally regulated immune response pathways after 6 days pi. At 7 days pi, elevated protein levels of infected bees may reflect synthesis of antimicrobial peptides from an initial immune response, but the lack of protein gain compared with uninfected bees at 14 days pi may represent low de novo protein synthesis. Carbohydrate data do not indicate that hosts experience severe metabolic stress related to this nutrient. At 14 days pi infected honey bees show high respirometric and activity levels, and corresponding lipid loss, suggesting lipids may be used as fuel for increased metabolic demands resulting from infection. Accelerated lipid loss during nurse honey bee behavioral development can have cascading effects on downstream physiology that may lead to precocious foraging, which is a major factor driving colony collapse. Published by Elsevier Ltd.

Distinct Luminal-Type Mammary Carcinomas Arise from Orthotopic Trp53-Null Mammary Transplantation of Juvenile versus Adult Mice

DOE PAGES

Nguyen, David H.; Ouyang, Haoxu; Mao, Jian-Hua; ...

2014-12-01

Age and physiologic status, such as menopause, are risk factors for breast cancer. Less clear is what factors influence the diversity of breast cancer. In this study, we investigated the effect of host age on the distribution of tumor subtypes in mouse mammary chimera consisting of wild-type hosts and Trp53 nullizygous epithelium, which undergoes a high rate of neoplastic transformation. Wild-type mammary glands cleared of endogenous epithelium at 3 weeks of age were subsequently transplanted during puberty (5 weeks) or at maturation (10 weeks) with syngeneic Trp53-null mammary tissue fragments and monitored for one year. Tumors arose sooner from adultmore » hosts (AH) compared with juvenile hosts (JH). However, compared with AH tumors, JH tumors grew several times faster, were more perfused, exhibited a two-fold higher mitotic index, and were more highly positive for insulin-like growth factor receptor phosphorylation. Most tumors in each setting were estrogen receptor (ER)-positive (80% JH vs. 70% AH), but JH tumors were significantly more ER-immunoreactive (P = 0.0001) than AH tumors. A differential expression signature (JvA) of juvenile versus adult tumors revealed a luminal transcriptional program. Centroids of the human homologs of JvA genes showed that JH tumors were more like luminal A tumors and AH tumors were more like luminal B tumors. Hierarchical clustering with the JvA human ortholog gene list segregated luminal A and luminal B breast cancers across datasets. Lastly, these data support the notion that age-associated host physiology greatly influences the intrinsic subtype of breast cancer.« less

Persistent Organic Pollutants Modify Gut Microbiota-Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation.

PubMed

Zhang, Limin; Nichols, Robert G; Correll, Jared; Murray, Iain A; Tanaka, Naoki; Smith, Philip B; Hubbard, Troy D; Sebastian, Aswathy; Albert, Istvan; Hatzakis, Emmanuel; Gonzalez, Frank J; Perdew, Gary H; Patterson, Andrew D

2015-07-01

Alteration of the gut microbiota through diet and environmental contaminants may disturb physiological homeostasis, leading to various diseases including obesity and type 2 diabetes. Because most exposure to environmentally persistent organic pollutants (POPs) occurs through the diet, the host gastrointestinal tract and commensal gut microbiota are likely to be exposed to POPs. We examined the effect of 2,3,7,8-tetrachlorodibenzofuran (TCDF), a persistent environmental contaminant, on gut microbiota and host metabolism, and we examined correlations between gut microbiota composition and signaling pathways. Six-week-old male wild-type and Ahr-/- mice on the C57BL/6J background were treated with 24 μg/kg TCDF in the diet for 5 days. We used 16S rRNA gene sequencing, 1H nuclear magnetic resonance (NMR) metabolomics, targeted ultra-performance liquid chromatography coupled with triplequadrupole mass spectrometry, and biochemical assays to determine the microbiota compositions and the physiological and metabolic effects of TCDF. Dietary TCDF altered the gut microbiota by shifting the ratio of Firmicutes to Bacteroidetes. TCDF-treated mouse cecal contents were enriched with Butyrivibrio spp. but depleted in Oscillobacter spp. compared with vehicle-treated mice. These changes in the gut microbiota were associated with altered bile acid metabolism. Further, dietary TCDF inhibited the farnesoid X receptor (FXR) signaling pathway, triggered significant inflammation and host metabolic disorders as a result of activation of bacterial fermentation, and altered hepatic lipogenesis, gluconeogenesis, and glycogenolysis in an AHR-dependent manner. These findings provide new insights into the biochemical consequences of TCDF exposure involving the alteration of the gut microbiota, modulation of nuclear receptor signaling, and disruption of host metabolism.

Distinct Luminal-Type Mammary Carcinomas Arise from Orthotopic Trp53-Null Mammary Transplantation of Juvenile versus Adult Mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, David H.; Ouyang, Haoxu; Mao, Jian-Hua

Age and physiologic status, such as menopause, are risk factors for breast cancer. Less clear is what factors influence the diversity of breast cancer. In this study, we investigated the effect of host age on the distribution of tumor subtypes in mouse mammary chimera consisting of wild-type hosts and Trp53 nullizygous epithelium, which undergoes a high rate of neoplastic transformation. Wild-type mammary glands cleared of endogenous epithelium at 3 weeks of age were subsequently transplanted during puberty (5 weeks) or at maturation (10 weeks) with syngeneic Trp53-null mammary tissue fragments and monitored for one year. Tumors arose sooner from adultmore » hosts (AH) compared with juvenile hosts (JH). However, compared with AH tumors, JH tumors grew several times faster, were more perfused, exhibited a two-fold higher mitotic index, and were more highly positive for insulin-like growth factor receptor phosphorylation. Most tumors in each setting were estrogen receptor (ER)-positive (80% JH vs. 70% AH), but JH tumors were significantly more ER-immunoreactive (P = 0.0001) than AH tumors. A differential expression signature (JvA) of juvenile versus adult tumors revealed a luminal transcriptional program. Centroids of the human homologs of JvA genes showed that JH tumors were more like luminal A tumors and AH tumors were more like luminal B tumors. Hierarchical clustering with the JvA human ortholog gene list segregated luminal A and luminal B breast cancers across datasets. Lastly, these data support the notion that age-associated host physiology greatly influences the intrinsic subtype of breast cancer.« less

The Gut Microbiota: Ecology and Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willing, B.P.; Jansson, J.K.

The gastrointestinal (GI) tract is teeming with an extremely abundant and diverse microbial community. The members of this community have coevolved along with their hosts over millennia. Until recently, the gut ecosystem was viewed as black box with little knowledge of who or what was there or their specific functions. Over the past decade, however, this ecosystem has become one of fastest growing research areas of focus in microbial ecology and human and animal physiology. This increased interest is largely in response to studies tying microbes in the gut to important diseases afflicting modern society, including obesity, allergies, inflammatory bowelmore » diseases, and diabetes. Although the importance of a resident community of microorganisms in health was first hypothesized by Pasteur over a century ago (Sears, 2005), the multiplicity of physiological changes induced by commensal bacteria has only recently been recognized (Hooper et al., 2001). The term 'ecological development' was recently coined to support the idea that development of the GI tract is a product of the genetics of the host and the host's interactions with resident microbes (Hooper, 2004). The search for new therapeutic targets and disease biomarkers has escalated the need to understand the identities and functions of the microorganisms inhabiting the gut. Recent studies have revealed new insights into the membership of the gut microbial community, interactions within that community, as well as mechanisms of interaction with the host. This chapter focuses on the microbial ecology of the gut, with an emphasis on information gleaned from recent molecular studies.« less

Effects of Long-Term Starvation on a Host Bivalve (Codakia orbicularis, Lucinidae) and Its Symbiont Population▿

PubMed Central

Caro, Audrey; Got, Patrice; Bouvy, Marc; Troussellier, Marc; Gros, Olivier

2009-01-01

The bivalve Codakia orbicularis, hosting sulfur-oxidizing gill endosymbionts, was starved (in artificial seawater filtered through a 0.22-μm-pore-size membrane) for a long-term experiment (4 months). The effects of starvation were observed using transmission electron microscopy, fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH), and flow cytometry to monitor the anatomical and physiological modifications in the gill organization of the host and in the symbiotic population housed in bacteriocytes. The abundance of the symbiotic population decreased through starvation, with a loss of one-third of the bacterial population each month, as shown by CARD-FISH. At the same time, flow cytometry revealed significant changes in the physiology of symbiotic cells, with a decrease in cell size and modifications to the nucleic acid content, while most of the symbionts maintained a high respiratory activity (measured using the 5-cyano-2,3-ditolyl tetrazolium chloride method). Progressively, the number of symbiont subpopulations was reduced, and the subsequent multigenomic state, characteristic of this symbiont in freshly collected clams, turned into one and five equivalent genome copies for the two remaining subpopulations after 3 months. Concomitant structural modifications appeared in the gill organization. Lysosymes became visible in the bacteriocytes, while large symbionts disappeared, and bacteriocytes were gradually replaced by granule cells throughout the entire lateral zone. Those data suggested that host survival under these starvation conditions was linked to symbiont digestion as the main nutritional source. PMID:19346359

Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria

PubMed Central

Augimeri, Richard V.; Varley, Andrew J.; Strap, Janice L.

2015-01-01

Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host–bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3′→5′)-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host–bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles. PMID:26635751

Comparing mechanisms of host manipulation across host and parasite taxa

USGS Publications Warehouse

Lafferty, Kevin D.; Shaw, Jenny C.

2013-01-01

Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

Parasitism, personality and cognition in fish.

PubMed

Barber, I; Mora, A B; Payne, E M; Weinersmith, K L; Sih, A

2017-08-01

It is well established that parasites can have profound effects on the behaviour of host organisms, and that individual differences in behaviour can influence susceptibility to parasite infections. Recently, two major themes of research have developed. First, there has been a growing interest in the proximate, mechanistic processes underpinning parasite-associated behaviour change, and the interactive roles of the neuro-, immune, and other physiological systems in determining relationships between behaviour and infection susceptibility. Secondly, as the study of behaviour has shifted away from one-off measurements of single behaviours and towards a behavioural syndromes/personality framework, research is starting to focus on the consequences of parasite infection for temporal and contextual consistency of behaviour, and on the implications of different personality types for infection susceptibility. In addition, there is increasing interest in the potential for relationships between cognition and personality to also have implications for host-parasite interactions. As models well-suited to both the laboratory study of behaviour and experimental parasitology, teleost fish have been used as hosts in many of these studies. In this review we provide a broad overview of the range of mechanisms that potentially generate links between fish behaviour, personality, and parasitism, and illustrate these using examples drawn from the recent literature. In addition, we examine the potential interactions between cognition, personality and parasitism, and identify questions that may be usefully investigated with fish models. Copyright © 2016 Elsevier B.V. All rights reserved.

Hemin activation of innate cellular response blocks human immunodeficiency virus type-1-induced osteoclastogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeda, Kazuyo; Adhikari, Rewati; Yamada, Kenneth M.

The normal skeletal developmental and homeostatic process termed osteoclastogenesis is exacerbated in numerous pathological conditions and causes excess bone loss. In cancer and HIV-1-infected patients, this disruption of homeostasis results in osteopenia and eventual osteoporesis. Counteracting the factors responsible for these metabolic disorders remains a challenge for preventing or minimizing this co-morbidity associated with these diseases. In this report, we demonstrate that a hemin-induced host protection mechanism not only suppresses HIV-1 associated osteoclastogenesis, but it also exhibits anti-osteoclastogenic activity for non-infected cells. Since the mode of action of hemin is both physiological and pharmacological through induction of heme oxygenase-1 (HO-1),more » an endogenous host protective response to an FDA-licensed therapeutic used to treat another disease, our study suggests an approach to developing novel, safe and effective therapeutic strategies for treating bone disorders, because hemin administration in humans has previously met required FDA safety standards. - Highlights: • HIV-1 infection induced osteoclastogenesis in primary human macrophages. • Heme oxygenase-1 (HO-1) induction inhibited HIV-1-induced osteoclastogenesis in macrophages. • HO-1 induction suppressed RANKL-enhanced osteoclastogenesis in HIV-1-infected macrophages. • This inverse relationship between HO-1 and HIV-1 pathogenesis may define a novel host defense response against HIV-1 infection.« less

Nitric oxide and heat shock protein 90 co-regulate temperature-induced bleaching in the soft coral Eunicea fusca

NASA Astrophysics Data System (ADS)

Ross, Cliff

2014-06-01

Coral bleaching represents a complex physiological process that is affected not only by environmental conditions but by the dynamic internal cellular biology of symbiotic dinoflagellates ( Symbiodinium spp.) and their cnidarian hosts. Recently, nitric oxide (NO) has emerged as a key molecule involved with the expulsion of Symbiodinium from host cnidarian cells. However, the site of production remains under debate, and the corresponding signaling pathways within and between host and endosymbiont remain elusive. In this study, using freshly isolated Symbiodinium from the soft coral Eunicea fusca, I demonstrate that thermally induced stress causes an upregulation in Symbiodinium heat shock protein 90 (Hsp90). In turn, Hsp90 shows a concomitant ability to enhance the activity of a constitutively expressed isoform of NO synthase. The resulting production of NO constitutes a signaling molecule capable of inducing Symbiodinium expulsion. Using nitric oxide synthase (NOS) and Hsp90 polyclonal antibodies, thermal stress-induced Hsp90 was shown to co-immunoprecipitate with a constitutive isoform of NOS. The specific blocking of Hsp90 activity, with the Hsp90 inhibitor geldanamycin, was capable of inhibiting NO production implicating the involvement of a coordinated regulatory system. These results have strong evolutionary implications for Hsp90-NOS chaperone complexes among biological kingdoms and provide evidence for a new functional role in symbiotic associations.

TOXOPLASMOSIS

PubMed Central

Halonen, Sandra K.; Weiss, Louis M.

2014-01-01

Toxoplasma gondii, an Apicomplexan, is a pathogen that can infect the central nervous system. Infection during pregnancy can result in a congenial infection with severe neurological sequela. In immune compromised individuals reactivation of latent neurological foci can result in encephalitis. Immune competent individuals infected with T. gondii are typically asymptomatic and maintain this infection for life. However, recent studies suggest that these asymptomatic infections may have effects on behavior and other physiological processes. T. gondii infects approximately one-third of the world population, making it one of the most successful parasitic organisms. Cats and other felidae serve as the definite host producing oocysts, an environmentally resistant life cycle stage found in cat feces, which can transmit the infection when ingested orally. A wide variety of warm-blooded animals, including humans, can serve as the intermediate host in which tissue cysts (containing bradyzoites) develop. Transmission also occurs due to ingestion of the tissue cysts. There are 3 predominant clonal lineages, termed types I, II and III and an association with higher pathogenicity with the Type I strains in humans has emerged. This chapter presents a review of the biology of this infection including the life cycle, transmission, epidemiology, parasite strains, and the host immune response. The major clinical outcomes of congenital infection, chorioretinitis, and encephalitis, and the possible association of infection of toxoplasmosis with neuropsychriatric disorders such as schizophrenia, are reviewed. PMID:23829904

Host partitioning by parasites in an intertidal crustacean community.

PubMed

Koehler, Anson V; Poulin, Robert

2010-10-01

Patterns of host use by parasites throughout a guild community of intermediate hosts can depend on several biological and ecological factors, including physiology, morphology, immunology, and behavior. We looked at parasite transmission in the intertidal crustacean community of Lower Portobello Bay, Dunedin, New Zealand, with the intent of: (1) mapping the flow of parasites throughout the major crustacean species, (2) identifying hosts that play the most important transmission role for each parasite, and (3) assessing the impact of parasitism on host populations. The most prevalent parasites found in 14 species of crustaceans (635 specimens) examined were the trematodes Maritrema novaezealandensis and Microphallus sp., the acanthocephalans Profilicollis spp., the nematode Ascarophis sp., and an acuariid nematode. Decapods were compatible hosts for M. novaezealandensis, while other crustaceans demonstrated lower host suitability as shown by high levels of melanized and immature parasite stages. Carapace thickness, gill morphology, and breathing style may contribute to the differential infection success of M. novaezealandensis and Microphallus sp. in the decapod species. Parasite-induced host mortality appears likely with M. novaezealandensis in the crabs Austrohelice crassa, Halicarcinus varius, Hemigrapsus sexdentatus, and Macrophthalmus hirtipes, and also with Microphallus sp. in A. crassa. Overall, the different parasite species make different use of available crustacean intermediate hosts and possibly contribute to intertidal community structure.

Development of a fed-batch process for a recombinant Pichia pastoris Δoch1 strain expressing a plant peroxidase.

PubMed

Gmeiner, Christoph; Saadati, Amirhossein; Maresch, Daniel; Krasteva, Stanimira; Frank, Manuela; Altmann, Friedrich; Herwig, Christoph; Spadiut, Oliver

2015-01-08

Pichia pastoris is a prominent host for recombinant protein production, amongst other things due to its capability of glycosylation. However, N-linked glycans on recombinant proteins get hypermannosylated, causing problems in subsequent unit operations and medical applications. Hypermannosylation is triggered by an α-1,6-mannosyltransferase called OCH1. In a recent study, we knocked out OCH1 in a recombinant P. pastoris CBS7435 Mut(S) strain (Δoch1) expressing the biopharmaceutically relevant enzyme horseradish peroxidase. We characterized the strain in the controlled environment of a bioreactor in dynamic batch cultivations and identified the strain to be physiologically impaired. We faced cell cluster formation, cell lysis and uncontrollable foam formation.In the present study, we investigated the effects of the 3 process parameters temperature, pH and dissolved oxygen concentration on 1) cell physiology, 2) cell morphology, 3) cell lysis, 4) productivity and 5) product purity of the recombinant Δoch1 strain in a multivariate manner. Cultivation at 30°C resulted in low specific methanol uptake during adaptation and the risk of methanol accumulation during cultivation. Cell cluster formation was a function of the C-source rather than process parameters and went along with cell lysis. In terms of productivity and product purity a temperature of 20°C was highly beneficial. In summary, we determined cultivation conditions for a recombinant P. pastoris Δoch1 strain allowing high productivity and product purity.

Gut Microbiota Dysbiosis in Obesity-Linked Metabolic Diseases and Prebiotic Potential of Polyphenol-Rich Extracts.

PubMed

Anhê, Fernando F; Varin, Thibault V; Le Barz, Mélanie; Desjardins, Yves; Levy, Emile; Roy, Denis; Marette, André

2015-12-01

Trillions of microorganisms inhabit the human body, strongly colonizing the gastro-intestinal tract and outnumbering our own cells. High-throughput sequencing techniques and new bioinformatic tools have enabled scientists to extend our knowledge on the relationship between the gut microbiota and host's physiology. Disruption of the ecological equilibrium in the gut (i.e., dysbiosis) has been associated with several pathological processes, including obesity and its related comorbidities, with diet being a strong determinant of gut microbial balance. In this review, we discuss the potential prebiotic effect of polyphenol-rich foods and extracts and how they can reshape the gut microbiota, emphasizing the novel role of the mucin-degrading bacterium Akkermansia muciniphila in their metabolic benefits.

Role of Ergothioneine in Microbial Physiology and Pathogenesis.

PubMed

Cumming, Bridgette M; Chinta, Krishna C; Reddy, Vineel P; Steyn, Adrie J C

2018-02-20

L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria, and some fungi. In contrast to other low-molecular-weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables the survival of microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection. Recent Advances: Ergothioneine has been reported to maintain bioenergetic homeostasis in Mtb and protect Mtb against oxidative stresses, thereby enhancing the virulence of Mtb in a mouse model. Furthermore, ergothioneine augments the resistance of Mtb to current frontline anti-TB drugs. Recently, an opportunistic fungus, Aspergillus fumigatus, which infects immunocompromised individuals, has been found to produce ergothioneine, which is important in conidial health and germination, and contributes to the fungal resistance against redox stresses. The molecular mechanisms of the functions of ergothioneine in microbial physiology and pathogenesis are poorly understood. It is currently not known if ergothioneine is used in detoxification or antioxidant enzymatic pathways. As ergothioneine is involved in bioenergetic and redox homeostasis and antibiotic susceptibility of Mtb, it is of utmost importance to advance our understanding of these mechanisms. A clear understanding of the role of ergothioneine in microbes will advance our knowledge of how this thione enhances microbial virulence and resistance to the host's defense mechanisms to avoid complete eradication. Antioxid. Redox Signal. 28, 431-444.

Host Plant Effects on Alkaline Phosphatase Activity in the Whiteflies, Bemisia tabaci Biotype B and Trialeurodes vaporariorum

PubMed Central

Yan, Ying; Peng, Lu; Liu, Wan-Xue; Wan, Fang-Hao; Harris, Marvin K.

2011-01-01

Bemisia tabaci (Gennadius) B-biotype and Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) often coexist on greenhouse-grown vegetable crops in northern China. The recent spread of B. tabaci B-biotype has largely replaced T. vaporariorum, and B-biotype now overlaps with T. vaporariorum where common hosts occur in most invaded areas. The impact of the B-biotype on the agro eco system appears to be widespread, and involves the ability to compete with and perhaps replace other phytophages like T. vaporariorum. An emerging hypothesis is that the B-biotype is physiologically superior due at least in part to an improved ability to metabolically utilize the alkaline phosphatase pathway. To test this hypothesis, alkaline phosphatase activity was studied in the B-biotype and T. vaporariorum after feeding on a number of different hosts for a range of durations, with and without host switching. Alkaline phosphatase activity in T. vaporariorum was 1.45 to 2.53-fold higher than that of the B-biotype when fed on tomato for 4 and 24 h, or switched from tomato to cotton and cabbage for the same durations. However, alkaline phosphatase activity in the B-biotype was 1.40 to 3.35-fold higher than that of T. vaporariorum when the host switching time was ∼72 and ∼120 h on the same plant. Both short-term (4 h) and long-term (72 h) switching of plant hosts can significantly affect the alkaline phosphatase activity in the two species. After ∼120 h, feeding on tomato and cotton alkaline phosphatase activity in the B-biotype was significantly higher than that of T. vaporariorum. It was shown that alkaline phosphatase aids the species feeding on different plant species, and that the B-biotype is physiologically superior to T. vaporariorum in utilizing the enzyme compared to T. vaporariorum over longer periods of feeding. PMID:21521136

Transcriptome Reprogramming by Plasmid-Encoded Transcriptional Regulators Is Required for Host Niche Adaption of a Macrophage Pathogen

PubMed Central

Coulson, Garry B.; Miranda-CasoLuengo, Aleksandra A.; Miranda-CasoLuengo, Raúl; Wang, Xiaoguang; Oliver, Jenna; Willingham-Lane, Jennifer M.

2015-01-01

Rhodococcus equi is a facultative intracellular pathogen of macrophages, relying on the presence of a conjugative virulence plasmid harboring a 21-kb pathogenicity island (PAI) for growth in host macrophages. The PAI encodes a family of 6 virulence-associated proteins (Vaps) in addition to 20 other proteins. The contribution of these to virulence has remained unclear. We show that the presence of only 3 virulence plasmid genes (of 73 in total) is required and sufficient for intracellular growth. These include a single vap family member, vapA, and two PAI-located transcriptional regulators, virR and virS. Both transcriptional regulators are essential for wild-type-level expression of vapA, yet vapA expression alone is not sufficient to allow intracellular growth. A whole-genome microarray analysis revealed that VirR and VirS substantially integrate themselves into the chromosomal regulatory network, significantly altering the transcription of 18% of all chromosomal genes. This pathoadaptation involved significant enrichment of select gene ontologies, in particular, enrichment of genes involved in transport processes, energy production, and cellular metabolism, suggesting a major change in cell physiology allowing the bacterium to grow in the hostile environment of the host cell. The results suggest that following the acquisition of the virulence plasmid by an avirulent ancestor of R. equi, coevolution between the plasmid and the chromosome took place, allowing VirR and VirS to regulate the transcription of chromosomal genes in a process that ultimately promoted intracellular growth. Our findings suggest a mechanism for cooption of existing chromosomal traits during the evolution of a pathogenic bacterium from an avirulent saprophyte. PMID:26015480

Transcriptome profiling of the honeybee parasite Varroa destructor provides new biological insights into the mite adult life cycle.

PubMed

Mondet, Fanny; Rau, Andrea; Klopp, Christophe; Rohmer, Marine; Severac, Dany; Le Conte, Yves; Alaux, Cedric

2018-05-04

The parasite Varroa destructor represents a significant threat to honeybee colonies. Indeed, development of Varroa infestation within colonies, if left untreated, often leads to the death of the colony. Although its impact on bees has been extensively studied, less is known about its biology and the functional processes governing its adult life cycle and adaptation to its host. We therefore developed a full life cycle transcriptomic catalogue in adult Varroa females and included pairwise comparisons with males, artificially-reared and non-reproducing females (10 life cycle stages and conditions in total). Extensive remodeling of the Varroa transcriptome was observed, with an upregulation of energetic and chitin metabolic processes during the initial and final phases of the life cycle (e.g. phoretic and post-oviposition stages), whereas during reproductive stages in brood cells genes showing functions related to transcriptional regulation were overexpressed. Several neurotransmitter and neuropeptide receptors involved in behavioural regulation, as well as active compounds of salivary glands, were also expressed at a higher level outside the reproductive stages. No difference was detected between artificially-reared phoretic females and their counterparts in colonies, or between females who failed to reproduce and females who successfully reproduced, indicating that phoretic individuals can be reared outside host colonies without impacting their physiology and that mechanisms underlying reproductive failure occur before oogenesis. We discuss how these new findings reveal the remarkable adaptation of Varroa to its host biology and notably to the switch from living on adults to reproducing in sealed brood cells. By spanning the entire adult life cycle, our work captures the dynamic changes in the parasite gene expression and serves as a unique resource for deciphering Varroa biology and identifying new targets for mite control.

Single variant bottleneck in the early dynamics of H. influenzae bacteremia in neonatal rats questions the theory of independent action

NASA Astrophysics Data System (ADS)

Shao, Xinxian; Levin, Bruce; Nemenman, Ilya

2017-08-01

There is an abundance of information about the genetic basis, physiological and molecular mechanisms of bacterial pathogenesis. In contrast, relatively little is known about population dynamic processes, by which bacteria colonize hosts and invade tissues and cells and thereby cause disease. In an article published in 1978, Moxon and Murphy presented evidence that, when inoculated intranasally with a mixture streptomycin sensitive and resistant (Sm S and Sm R ) and otherwise isogenic strains of Haemophilus influenzae type b (Hib), neonatal rats develop a bacteremic infection that often is dominated by only one strain, Sm S or Sm R . After ruling out other possibilities through years of related experiments, the field seems to have settled on a plausible explanation for this phenomenon: the first bacterium to invade the host activates the host immune response that ‘shuts the door’ on the second invading strain. To explore this hypothesis in a necessarily quantitative way, we modeled this process with a set of mixed stochastic and deterministic differential equations. Our analysis of the properties of this model with realistic parameters suggests that this hypothesis cannot explain the experimental results of Moxon and Murphy, and in particular the observed relationship between the frequency of different types of blood infections (bacteremias) and the inoculum size. We propose modifications to the model that come closer to explaining these data. However, the modified and better fitting model contradicts the common theory of independent action of individual bacteria in establishing infections. We suggest possible experiments that would be able to confirm or reject our proposed modification of the early infection model.

Apicomplexans pulling the strings: manipulation of the host cell cytoskeleton dynamics.

PubMed

Cardoso, Rita; Soares, Helena; Hemphill, Andrew; Leitão, Alexandre

2016-07-01

Invasive stages of apicomplexan parasites require a host cell to survive, proliferate and advance to the next life cycle stage. Once invasion is achieved, apicomplexans interact closely with the host cell cytoskeleton, but in many cases the different species have evolved distinct mechanisms and pathways to modulate the structural organization of cytoskeletal filaments. The host cell cytoskeleton is a complex network, largely, but not exclusively, composed of microtubules, actin microfilaments and intermediate filaments, all of which are modulated by associated proteins, and it is involved in diverse functions including maintenance of cell morphology and mechanical support, migration, signal transduction, nutrient uptake, membrane and organelle trafficking and cell division. The ability of apicomplexans to modulate the cytoskeleton to their own advantage is clearly beneficial. We here review different aspects of the interactions of apicomplexans with the three main cytoskeletal filament types, provide information on the currently known parasite effector proteins and respective host cell targets involved, and how these interactions modulate the host cell physiology. Some of these findings could provide novel targets that could be exploited for the development of preventive and/or therapeutic strategies.

Repeat-containing protein effectors of plant-associated organisms

PubMed Central

Mesarich, Carl H.; Bowen, Joanna K.; Hamiaux, Cyril; Templeton, Matthew D.

2015-01-01

Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs) that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms. PMID:26557126

Repeat-containing protein effectors of plant-associated organisms.

PubMed

Mesarich, Carl H; Bowen, Joanna K; Hamiaux, Cyril; Templeton, Matthew D

2015-01-01

Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs) that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms.

Does the Host Contribute to Modulation of Mycotoxin Production by Fruit Pathogens?

PubMed Central

Kumar, Dilip; Barad, Shiri; Sionov, Edward; Prusky, Dov B.

2017-01-01

Storage of freshly harvested fruit is a key factor in modulating their supply for several months after harvest; however, their quality can be reduced by pathogen attack. Fruit pathogens may infect their host through damaged surfaces, such as mechanical injuries occurring during growing, harvesting, and packing, leading to increased colonization as the fruit ripens. Of particular concern are fungal pathogens that not only macerate the host tissue but also secrete significant amounts of mycotoxins. Many studies have described the importance of physiological factors, including stage of fruit development, biochemical factors (ripening, C and N content), and environmental factors (humidity, temperature, water deficit) on the occurrence of mycotoxins. However, those factors usually show a correlative effect on fungal growth and mycotoxin accumulation. Recent reports have suggested that host factors can induce fungal metabolism, leading to the synthesis and accumulation of mycotoxins. This review describes the new vision of host-factor impact on the regulation of mycotoxin biosynthetic gene clusters underlying the complex regulation of mycotoxin accumulation in ripening fruit. PMID:28895896

Influence of early life exposure, host genetics and diet on the mouse gut microbiome and metabolome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snijders, Antoine M.; Langley, Sasha A.; Kim, Young-Mo

Although the gut microbiome plays important roles in host physiology, health and disease1, we lack understanding of the complex interplay between host genetics and early life environment on the microbial and metabolic composition of the gut.We used the genetically diverse Collaborative Cross mouse system2 to discover that early life history impacts themicrobiome composition, whereas dietary changes have only a moderate effect. By contrast, the gut metabolome was shaped mostly by diet, with specific non-dietary metabolites explained by microbial metabolism. Quantitative trait analysis identified mouse genetic trait loci (QTL) that impact the abundances of specific microbes. Human orthologues of genes inmore » the mouse QTL are implicated in gastrointestinal cancer. Additionally, genes located in mouse QTL for Lactobacillales abundance are implicated in arthritis, rheumatic disease and diabetes. Furthermore, Lactobacillales abundance was predictive of higher host T-helper cell counts, suggesting an important link between Lactobacillales and host adaptive immunity.« less

Getting to the Outer Leaflet: Physiology of Phosphatidylserine Exposure at the Plasma Membrane.

PubMed

Bevers, Edouard M; Williamson, Patrick L

2016-04-01

Phosphatidylserine (PS) is a major component of membrane bilayers whose change in distribution between inner and outer leaflets is an important physiological signal. Normally, members of the type IV P-type ATPases spend metabolic energy to create an asymmetric distribution of phospholipids between the two leaflets, with PS confined to the cytoplasmic membrane leaflet. On occasion, membrane enzymes, known as scramblases, are activated to facilitate transbilayer migration of lipids, including PS. Recently, two proteins required for such randomization have been identified: TMEM16F, a scramblase regulated by elevated intracellular Ca(2+), and XKR8, a caspase-sensitive protein required for PS exposure in apoptotic cells. Once exposed at the cell surface, PS regulates biochemical reactions involved in blood coagulation, and bone mineralization, and also regulates a variety of cell-cell interactions. Exposed on the surface of apoptotic cells, PS controls their recognition and engulfment by other cells. This process is exploited by parasites to invade their host, and in specialized form is used to maintain photoreceptors in the eye and modify synaptic connections in the brain. This review discusses what is known about the mechanism of PS exposure at the surface of the plasma membrane of cells, how actors in the extracellular milieu sense surface exposed PS, and how this recognition is translated to downstream consequences of PS exposure. Copyright © 2016 the American Physiological Society.

Eye fluke-induced cataracts in natural fish populations: is there potential for host manipulation?

PubMed

Seppälä, O; Karvonen, A; Valtonen, E T

2011-02-01

Manipulation of host phenotype (e.g. behaviour, appearance) is suggested to be a common strategy to enhance transmission in trophically transmitted parasites. However, in many systems, evidence of manipulation comes exclusively from laboratory studies and its occurrence in natural host populations is poorly understood. Here, we examined the potential for host manipulation by Diplostomum eye flukes indirectly by quantifying the physiological effects of parasites on fish. Earlier laboratory studies have shown that Diplostomum infection predisposes fish to predation by birds (definitive hosts of the parasites) by reducing fish vision through cataract formation. However, occurrence of cataracts and the subsequent potential for host manipulation in natural fish populations has remained poorly explored. We studied the occurrence of eye fluke-induced cataracts from 7 common fish species (Gymnocephalus cernuus, Rutilus rutilus, Leuciscus leuciscus, Alburnus alburnus, Osmerus eperlanus, Coregonus lavaretus and Gasterosteus aculeatus) from the Bothnian Bay in the Baltic Sea. We found that the parasite-induced cataracts were common in fish and they also reached high levels which are likely to predispose fish to predation. However, we observed such cataracts only in species with the highest parasite abundances, which suggests that only certain hosts may be strongly affected by the infection.

Parasitoid flies exploiting acoustic communication of insects-comparative aspects of independent functional adaptations.

PubMed

Lakes-Harlan, Reinhard; Lehmann, Gerlind U C

2015-01-01

Two taxa of parasitoid Diptera have independently evolved tympanal hearing organs to locate sound producing host insects. Here we review and compare functional adaptations in both groups of parasitoids, Ormiini and Emblemasomatini. Tympanal organs in both groups originate from a common precursor organ and are somewhat similar in morphology and physiology. In terms of functional adaptations, the hearing thresholds are largely adapted to the frequency spectra of the calling song of the hosts. The large host ranges of some parasitoids indicate that their neuronal filter for the temporal patterns of the calling songs are broader than those found in intraspecific communication. For host localization the night active Ormia ochracea and the day active E. auditrix are able to locate a sound source precisely in space. For phonotaxis flight and walking phases are used, whereby O. ochracea approaches hosts during flight while E. auditrix employs intermediate landings and re-orientation, apparently separating azimuthal and vertical angles. The consequences of the parasitoid pressure are discussed for signal evolution and intraspecific communication of the host species. This natural selection pressure might have led to different avoidance strategies in the hosts: silent males in crickets, shorter signals in tettigoniids and fluctuating population abundances in cicadas.

Interaction of entomopathogenic fungi with the host immune system.

PubMed

Qu, Shuang; Wang, Sibao

2018-06-01

Entomopathogenic fungi can invade wide range of insect hosts in the natural world and have been used as environmentally friendly alternatives to chemical insecticides for pest control. Studies of host-pathogen interactions provide valuable insights into the coevolutionay arms race between fungal pathogens and their hosts. Entomopathogenic fungi have evolved a series of sophisticated strategies to counter insect immune defenses. In response to fungal infection, insect hosts rely on behavior avoidance, physical barrier and innate immune defenses in the fight against invading pathogens. The insect cuticle acts as the first physical barrier against pathogens. It is an inhospitable physiological environment that contains chemicals (e.g., antimicrobial peptides and reactive oxygen species), which inhibit fungal growth. In addition, innate immune responses, including cellular immunity and humoral immunity, play critical roles in preventing fungal infection. In this review, we outline the current state of our knowledge of insect defenses to fungal infection and discuss the strategies by which entomopathogenic fungi counter the host immune system. Increased knowledge regarding the molecular interactions between entomopathogenic fungi and the insect host could provide new strategies for pest management. Copyright © 2018 Elsevier Ltd. All rights reserved.

A mathematical approach to HIV infection dynamics

NASA Astrophysics Data System (ADS)

Ida, A.; Oharu, S.; Oharu, Y.

2007-07-01

In order to obtain a comprehensive form of mathematical models describing nonlinear phenomena such as HIV infection process and AIDS disease progression, it is efficient to introduce a general class of time-dependent evolution equations in such a way that the associated nonlinear operator is decomposed into the sum of a differential operator and a perturbation which is nonlinear in general and also satisfies no global continuity condition. An attempt is then made to combine the implicit approach (usually adapted for convective diffusion operators) and explicit approach (more suited to treat continuous-type operators representing various physiological interactions), resulting in a semi-implicit product formula. Decomposing the operators in this way and considering their individual properties, it is seen that approximation-solvability of the original model is verified under suitable conditions. Once appropriate terms are formulated to describe treatment by antiretroviral therapy, the time-dependence of the reaction terms appears, and such product formula is useful for generating approximate numerical solutions to the governing equations. With this knowledge, a continuous model for HIV disease progression is formulated and physiological interpretations are provided. The abstract theory is then applied to show existence of unique solutions to the continuous model describing the behavior of the HIV virus in the human body and its reaction to treatment by antiretroviral therapy. The product formula suggests appropriate discrete models describing the dynamics of host pathogen interactions with HIV1 and is applied to perform numerical simulations based on the model of the HIV infection process and disease progression. Finally, the results of our numerical simulations are visualized and it is observed that our results agree with medical and physiological aspects.

Oviposition by mutualistic seed-consuming pollinators reduces fruit abortion in a recently discovered pollination mutualism

PubMed Central

Song, Bo; Stöcklin, Jürg; Gao, Yong-Qian; Peng, De-Li; Song, Min-Shu; Sun, Hang

2016-01-01

A prerequisite for the evolutionary stability of pollinating seed-consuming mutualisms is that each partner benefits from the association. However, few studies of such mutualism have considered the benefit gained by the pollinators. Here, we determined how the pollinating seed-predators ensure the provisioning of their offspring in the recently discovered mutualism between Rheum nobile and Bradysia flies. The correlation between flower fate and fly oviposition was examined. Floral traits and patterns of variation in fruit abortion and fly oviposition were investigated to determine whether female flies exhibit preferences for particular flowers when laying eggs. Indole-3-acetic acid (IAA) was quantified to determine whether female flies manipulate host physiology. Flowers that flies oviposited on had a significantly lower probability of fruit abortion compared with intact flowers. Females did not exhibit oviposition preference for any of the floral traits examined. There was no significant correlation between fruit abortion and fly oviposition in terms of either flower position or timing of flowering. IAA concentrations in oviposited flowers were significantly higher than in intact flowers. Our results suggest that oviposition by the mutualistic seed-consuming pollinator Bradysia sp., greatly reduces the probability of fruit abortion of its host, R. nobile; this may be attributed to the manipulation of host physiology through regulating IAA levels. PMID:27418228

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys (Cercocebus torquatus) following antiparasitic treatment

PubMed Central

Ziegler, Toni E.; Goldberg, Tony L.

2016-01-01

Parasites are ubiquitous in wildlife populations, but physiological and behavioural responses of hosts to infection are difficult to measure. We experimentally treated semi-free-ranging red-capped mangabeys (Cercocebus torquatus) in Nigeria with antiparasitic drugs and examined subsequent changes in glucocorticoid production and individual behaviour. Because both parasites and stress impact energy balance and health, we measured (i) behavioural time re-allocation via activity budgets, (ii) social relationships (e.g. social connectivity and dominance hierarchy stability) and (iii) body condition. We collected triplicate faecal samples (n = 441) from 49 individuals prior to and following treatment. Cortisol levels fluctuated in parallel with parasite abundance. Elevations in cortisol, but not parasitism, were related to reduced body condition. Behaviour also shifted according to infection status, with uninfected individuals spending more time foraging and less time resting and vigilant compared with when they were infected. Time spent feeding, travelling or socializing did not differ between pre- and post-treatment time periods. Group cohesion, but not dominance stability, changed following treatment, suggesting parasite-induced social avoidance. Together, these findings show a coordinated response to infection that promotes host tolerance through stress and energy conservation, reduces transmission risk and increases protection when infected hosts are vulnerable. PMID:27466454

Intrinsic disorder in pathogen effectors: protein flexibility as an evolutionary hallmark in a molecular arms race.

PubMed

Marín, Macarena; Uversky, Vladimir N; Ott, Thomas

2013-09-01

Effector proteins represent a refined mechanism of bacterial pathogens to overcome plants' innate immune systems. These modular proteins often manipulate host physiology by directly interfering with immune signaling of plant cells. Even if host cells have developed efficient strategies to perceive the presence of pathogenic microbes and to recognize intracellular effector activity, it remains an open question why only few effectors are recognized directly by plant resistance proteins. Based on in-silico genome-wide surveys and a reevaluation of published structural data, we estimated that bacterial effectors of phytopathogens are highly enriched in long-disordered regions (>50 residues). These structurally flexible segments have no secondary structure under physiological conditions but can fold in a stimulus-dependent manner (e.g., during protein-protein interactions). The high abundance of intrinsic disorder in effectors strongly suggests positive evolutionary selection of this structural feature and highlights the dynamic nature of these proteins. We postulate that such structural flexibility may be essential for (1) effector translocation, (2) evasion of the innate immune system, and (3) host function mimicry. The study of these dynamical regions will greatly complement current structural approaches to understand the molecular mechanisms of these proteins and may help in the prediction of new effectors.

Intraspecific Competition Impacts Vibrio fischeri Strain Diversity during Initial Colonization of the Squid Light Organ

PubMed Central

Sun, Yan; LaSota, Elijah D.; Cecere, Andrew G.; LaPenna, Kyle B.; Larios-Valencia, Jessie; Wollenberg, Michael S.

2016-01-01

ABSTRACT Animal development and physiology depend on beneficial interactions with microbial symbionts. In many cases, the microbial symbionts are horizontally transmitted among hosts, thereby making the acquisition of these microbes from the environment an important event within the life history of each host. The light organ symbiosis established between the Hawaiian squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri is a model system for examining how hosts acquire horizontally transmitted microbial symbionts. Recent studies have revealed that the light organ of wild-caught E. scolopes squid contains polyclonal populations of V. fischeri bacteria; however, the function and development of such strain diversity in the symbiosis are unknown. Here, we report our phenotypic and phylogenetic characterizations of FQ-A001, which is a V. fischeri strain isolated directly from the light organ of an E. scolopes individual. Relative to the type strain ES114, FQ-A001 exhibits similar growth in rich medium but displays increased bioluminescence and decreased motility in soft agar. FQ-A001 outcompetes ES114 in colonizing the crypt spaces of the light organs. Remarkably, we find that animals cocolonized with FQ-A001 and ES114 harbor singly colonized crypts, in contrast to the cocolonized crypts observed from competition experiments involving single genotypes. The results with our two-strain system suggest that strain diversity within the squid light organ is a consequence of diversity in the single-strain colonization of individual crypt spaces. IMPORTANCE The developmental programs and overall physiologies of most animals depend on diverse microbial symbionts that are acquired from the environment. However, the basic principles underlying how microbes colonize their hosts remain poorly understood. Here, we report our findings of bacterial strain competition within the coevolved animal-microbe symbiosis composed of the Hawaiian squid and bioluminescent bacterium Vibrio fischeri. Using fluorescent proteins to differentially label two distinct V. fischeri strains, we find that the strains are unable to coexist in the same niche within the host. Our results suggest that strain competition for distinct colonization sites dictates the strain diversity associated with the host. Our study provides a platform for studying how strain diversity develops within a host. PMID:27016564

Individual Apostichopus japonicus fecal microbiome reveals a link with polyhydroxybutyrate producers in host growth gaps.

PubMed

Yamazaki, Yohei; Meirelles, Pedro Milet; Mino, Sayaka; Suda, Wataru; Oshima, Kenshiro; Hattori, Masahira; Thompson, Fabiano L; Sakai, Yuichi; Sawabe, Toko; Sawabe, Tomoo

2016-02-24

Gut microbiome shapes various aspects of a host's physiology, but these functions in aquatic animal hosts have yet to be fully investigated. The sea cucumber Apostichopus japonicus Selenka is one such example. The large growth gap in their body size has delayed the development of intensive aquaculture, nevertheless the species is in urgent need of conservation. To understand possible contributions of the gut microbiome to its host's growth, individual fecal microbiome comparisons were performed. High-throughput 16S rRNA sequencing revealed significantly different microbiota in larger and smaller individuals; Rhodobacterales in particular was the most significantly abundant bacterial group in the larger specimens. Further shotgun metagenome of representative samples revealed a significant abundance of microbiome retaining polyhydroxybutyrate (PHB) metabolism genes in the largest individual. The PHB metabolism reads were potentially derived from Rhodobacterales. These results imply a possible link between microbial PHB producers and potential growth promotion in Deuterostomia marine invertebrates.

Salt, chloride, bleach, and innate host defense

PubMed Central

Wang, Guoshun; Nauseef, William M.

2015-01-01

Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense. PMID:26048979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snijders, Antoine M.; Langley, Sasha A.; Kim, Young-Mo

Although the gut microbiome plays important roles in host physiology, health and disease1, we lack understanding of the complex interplay between host genetics and early life environment on the microbial and metabolic composition of the gut.We used the genetically diverse Collaborative Cross mouse system2 to discover that early life history impacts themicrobiome composition, whereas dietary changes have only a moderate effect. By contrast, the gut metabolome was shaped mostly by diet, with specific non-dietary metabolites explained by microbial metabolism. Quantitative trait analysis identified mouse genetic trait loci (QTL) that impact the abundances of specific microbes. Human orthologues of genes inmore » the mouse QTL are implicated in gastrointestinal cancer. Additionally, genes located in mouse QTL for Lactobacillales abundance are implicated in arthritis, rheumatic disease and diabetes. Furthermore, Lactobacillales abundance was predictive of higher host T-helper cell counts, suggesting an important link between Lactobacillales and host adaptive immunity.« less

Salt, chloride, bleach, and innate host defense.

PubMed

Wang, Guoshun; Nauseef, William M

2015-08-01

Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense. © Society for Leukocyte Biology.

Mechanisms of cross-talk between the diet, the intestinal microbiome, and the undernourished host

PubMed Central

Velly, Helene; Britton, Robert A.; Preidis, Geoffrey A.

2017-01-01

ABSTRACT Undernutrition remains one of the most pressing global health challenges today, contributing to nearly half of all deaths in children under five years of age. Although insufficient dietary intake and environmental enteric dysfunction are often inciting factors, evidence now suggests that unhealthy gut microbial populations perpetuate the vicious cycle of pathophysiology that results in persistent growth impairment in children. The metagenomics era has facilitated new research identifying an altered microbiome in undernourished hosts and has provided insight into a number of mechanisms by which these alterations may affect growth. This article summarizes a range of observational studies that highlight differences in the composition and function of gut microbiota between undernourished and healthy children; discusses dietary, environmental and host factors that shape this altered microbiome; examines the consequences of these changes on host physiology; and considers opportunities for microbiome-targeting therapies to combat the global challenge of child undernutrition. PMID:27918230

Chemosensation of Bacterial Secondary Metabolites Modulates Neuroendocrine Signaling and Behavior of C. elegans

PubMed Central

Meisel, Joshua D.; Panda, Oishika; Mahanti, Parag; Schroeder, Frank C.; Kim, Dennis H.

2014-01-01

Summary Discrimination among pathogenic and beneficial microbes is essential for host organism immunity and homeostasis. Here, we show that chemosensory detection of two secondary metabolites produced by Pseudomonas aeruginosa modulates a neuroendocrine signaling pathway that promotes avoidance behavior in the simple animal host Caenorhabditis elegans. Secondary metabolites phenazine-1-carboxamide and pyochelin activate a G protein-signaling pathway in the ASJ chemosensory neuron pair that induces expression of the neuromodulator DAF-7/TGF-β. DAF-7, in turn, activates a canonical TGF-β signaling pathway in adjacent interneurons to modulate aerotaxis behavior and promote avoidance of pathogenic P. aeruginosa. Our data provide a chemical, genetic, and neuronal basis for how the behavior and physiology of a simple animal host can be modified by the microbial environment, and suggest that secondary metabolites produced by microbes may provide environmental cues that contribute to pathogen recognition and host survival. PMID:25303524

Regulation of inflammation by microbiota interactions with the host.

PubMed

Blander, J Magarian; Longman, Randy S; Iliev, Iliyan D; Sonnenberg, Gregory F; Artis, David

2017-07-19

The study of the intestinal microbiota has begun to shift from cataloging individual members of the commensal community to understanding their contributions to the physiology of the host organism in health and disease. Here, we review the effects of the microbiome on innate and adaptive immunological players from epithelial cells and antigen-presenting cells to innate lymphoid cells and regulatory T cells. We discuss recent studies that have identified diverse microbiota-derived bioactive molecules and their effects on inflammation within the intestine and distally at sites as anatomically remote as the brain. Finally, we highlight new insights into how the microbiome influences the host response to infection, vaccination and cancer, as well as susceptibility to autoimmune and neurodegenerative disorders.

Remote reprogramming of hepatic circadian transcriptome by breast cancer.

PubMed

Hojo, Hiroaki; Enya, Sora; Arai, Miki; Suzuki, Yutaka; Nojiri, Takashi; Kangawa, Kenji; Koyama, Shinsuke; Kawaoka, Shinpei

2017-05-23

Cancers adversely affect organismal physiology. To date, the genes within a patient responsible for systemically spreading cancer-induced physiological disruption remain elusive. To identify host genes responsible for transmitting disruptive, cancer-driven signals, we thoroughly analyzed the transcriptome of a suite of host organs from mice bearing 4T1 breast cancer, and discovered complexly rewired patterns of circadian gene expression in the liver. Our data revealed that 7 core clock transcription factors, represented by Rev-erba and Rorg, exhibited abnormal daily expression rhythm in the liver of 4T1-bearing mice. Accordingly, expression patterns of specific set of downstream circadian genes were compromised. Osgin1, a marker for oxidative stress, was an example. Specific downstream genes, including E2f8, a transcriptional repressor that controls cellular polyploidy, displayed a striking pattern of disruption, "day-night reversal." Meanwhile, we found that the liver of 4T1-bearing mice suffered from increased oxidative stress. The tetraploid hepatocytes population was concomitantly increased in 4T1-bearing mice, which has not been previously appreciated as a cancer-induced phenotype. In summary, the current study provides a comprehensive characterization of the 4T1-affected hepatic circadian transcriptome that possibly underlies cancer-induced physiological alteration in the liver.

Sex-biased avian host use by arbovirus vectors.

PubMed

Burkett-Cadena, Nathan D; Bingham, Andrea M; Unnasch, Thomas R

2014-11-01

Prevalence of arthropod-borne parasites often differs drastically between host sexes. This sex-related disparity may be related to physiological (primarily hormonal) differences that facilitate or suppress replication of the pathogen in host tissues. Alternately, differences in pathogen prevalence between host sexes may be owing to differential exposure to infected vectors. Here, we report on the use of PCR-based assays recognizing bird sex chromosomes to investigate sex-related patterns of avian host use from field-collected female mosquitoes from Florida, USA. Mosquitoes took more bloodmeals from male birds (64.0% of 308 sexed samples) than female birds (36.0%), deviating significantly from a hypothetical 1:1 sex ratio. In addition, male-biased host use was consistent across mosquito species (Culex erraticus (64.4%); Culex nigripalpus (61.0%) and Culiseta melanura (64.9%)). Our findings support the hypothesis that sex-biased exposure to vector-borne pathogens contributes to disparities in parasite/pathogen prevalence between the sexes. While few studies have yet to investigate sex-biased host use by mosquitoes, the methods used here could be applied to a variety of mosquito-borne disease systems, including those that affect health of humans, domestic animals and wildlife. Understanding the mechanisms that drive sex-based disparities in host use may lead to novel strategies for interrupting pathogen/parasite transmission.

Water-seeking behavior in worm-infected crickets and reversibility of parasitic manipulation

PubMed Central

Ponton, Fleur; Lefèvre, Thierry; Guerin, Patrick M.; Lebarbenchon, Camille; Duneau, David; Biron, David G.; Thomas, Frédéric

2011-01-01

One of the most fascinating examples of parasite-induced host manipulation is that of hairworms, first, because they induce a spectacular “suicide” water-seeking behavior in their terrestrial insect hosts and, second, because the emergence of the parasite is not lethal per se for the host that can live several months following parasite release. The mechanisms hairworms use to increase the encounter rate between their host and water remain, however, poorly understood. Considering the selective landscape in which nematomorph manipulation has evolved as well as previously obtained proteomics data, we predicted that crickets harboring mature hairworms would display a modified behavioral response to light. Since following parasite emergence in water, the cricket host and parasitic worm do not interact physiologically anymore, we also predicted that the host would recover from the modified behaviors. We examined the effect of hairworm infection on different behavioral responses of the host when stimulated by light to record responses from uninfected, infected, and ex-infected crickets. We showed that hairworm infection fundamentally modifies cricket behavior by inducing directed responses to light, a condition from which they mostly recover once the parasite is released. This study supports the idea that host manipulation by parasites is subtle, complex, and multidimensional. PMID:22476265

Size matters for lice on birds: Coevolutionary allometry of host and parasite body size.

PubMed

Harnos, Andrea; Lang, Zsolt; Petrás, Dóra; Bush, Sarah E; Szabó, Krisztián; Rózsa, Lajos

2017-02-01

Body size is one of the most fundamental characteristics of all organisms. It influences physiology, morphology, behavior, and even interspecific interactions such as those between parasites and their hosts. Host body size influences the magnitude and variability of parasite size according to Harrison's rule (HR: positive relationship between host and parasite body sizes) and Poulin's Increasing Variance Hypothesis (PIVH: positive relationship between host body size and the variability of parasite body size). We analyzed parasite-host body size allometry for 581 species of avian lice (∼15% of known diversity) and their hosts. We applied phylogenetic generalized least squares (PGLS) methods to account for phylogenetic nonindependence controlling for host and parasite phylogenies separately and variance heterogeneity. We tested HR and PIVH for the major families of avian lice (Ricinidae, Menoponidae, Philopteridae), and for distinct ecological guilds within Philopteridae. Our data indicate that most families and guilds of avian lice follow both HR and PIVH; however, ricinids did not follow PIVH and the "body lice" guild of philopterid lice did not follow HR or PIVH. We discuss mathematical and ecological factors that may be responsible for these patterns, and we discuss the potential pervasiveness of these relationships among all parasites on Earth. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Patterns of host-plant choice in bees of the genus Chelostoma: the constraint hypothesis of host-range evolution in bees.

PubMed

Sedivy, Claudio; Praz, Christophe J; Müller, Andreas; Widmer, Alex; Dorn, Silvia

2008-10-01

To trace the evolution of host-plant choice in bees of the genus Chelostoma (Megachilidae), we assessed the host plants of 35 Palearctic, North American and Indomalayan species by microscopically analyzing the pollen loads of 634 females and reconstructed their phylogenetic history based on four genes and a morphological dataset, applying both parsimony and Bayesian methods. All species except two were found to be strict pollen specialists at the level of plant family or genus. These oligolectic species together exploit the flowers of eight different plant orders that are distributed among all major angiosperm lineages. Based on ancestral state reconstruction, we found that oligolecty is the ancestral state in Chelostoma and that the two pollen generalists evolved from oligolectic ancestors. The distinct pattern of host broadening in these two polylectic species, the highly conserved floral specializations within the different clades, the exploitation of unrelated hosts with a striking floral similarity as well as a recent report on larval performance on nonhost pollen in two Chelostoma species clearly suggest that floral host choice is physiologically or neurologically constrained in bees of the genus Chelostoma. Based on this finding, we propose a new hypothesis on the evolution of host range in bees.

Functional microorganisms for functional food quality.

PubMed

Gobbetti, M; Cagno, R Di; De Angelis, M

2010-09-01

Functional microorganisms and health benefits represent a binomial with great potential for fermented functional foods. The health benefits of fermented functional foods are expressed either directly through the interactions of ingested live microorganisms with the host (probiotic effect) or indirectly as the result of the ingestion of microbial metabolites synthesized during fermentation (biogenic effect). Since the importance of high viability for probiotic effect, two major options are currently pursued for improving it--to enhance bacterial stress response and to use alternative products for incorporating probiotics (e.g., ice cream, cheeses, cereals, fruit juices, vegetables, and soy beans). Further, it seems that quorum sensing signal molecules released by probiotics may interact with human epithelial cells from intestine thus modulating several physiological functions. Under optimal processing conditions, functional microorganisms contribute to food functionality through their enzyme portfolio and the release of metabolites. Overproduction of free amino acids and vitamins are two classical examples. Besides, bioactive compounds (e.g., peptides, γ-amino butyric acid, and conjugated linoleic acid) may be released during food processing above the physiological threshold and they may exert various in vivo health benefits. Functional microorganisms are even more used in novel strategies for decreasing phenomenon of food intolerance (e.g., gluten intolerance) and allergy. By a critical approach, this review will aim at showing the potential of functional microorganisms for the quality of functional foods.

The Circadian Clock in Cancer Development and Therapy

PubMed Central

Fu, Loning; Kettner, Nicole M.

2014-01-01

Most aspects of mammalian function display circadian rhythms driven by an endogenous clock. The circadian clock is operated by genes and comprises a central clock in the brain that responds to environmental cues and controls subordinate clocks in peripheral tissues via circadian output pathways. The central and peripheral clocks coordinately generate rhythmic gene expression in a tissue-specific manner in vivo to couple diverse physiological and behavioral processes to periodic changes in the environment. However, as the world industrialized, activities that disrupt endogenous homeostasis with external circadian cues have increased. This change in lifestyle has been linked to increased risk of diseases in all aspects of human health, including cancer. Studies in humans and animal models have revealed that cancer development in vivo is closely associated with the loss of circadian homeostasis in energy balance, immune function and aging that are supported by cellular functions important for tumor suppression including cell proliferation, senescence, metabolism and DNA damage response. The clock controls these cellular functions both locally in cells of peripheral tissues and at the organismal level via extracellular signaling. Thus, the hierarchical mammalian circadian clock provides a unique system to study carcinogenesis as a deregulated physiological process in vivo. The asynchrony between host and malignant tissues in cell proliferation and metabolism also provides new and exciting options for novel anti-cancer therapies. PMID:23899600

Indirect Plant Defense against Insect Herbivores: A Review

USDA-ARS?s Scientific Manuscript database

Plants respond to herbivore attack by launching two types of defenses: direct defense and indirect defense. Direct defense includes all plant traits that increase the resistance of host plants to attacking insect herbivores by affecting the physiology and/or behavior of the attackers. Indirect defe...

Metagenomics detects functional shifts in the bovine rumen microbiota in response to propionate intake

USDA-ARS?s Scientific Manuscript database

Optimizing rumen microbial ecosystem output is essential towards improved ruminant agriculture. Ruminal infusion or intake of propionate, one of the predominant volatile fatty acids, has important implications for host physiology. However, how the rumen microbiota responds to propionate administrat...

Mycobacterial lipolytic enzymes: a gold mine for tuberculosis research.

PubMed

Dedieu, L; Serveau-Avesque, C; Kremer, L; Canaan, S

2013-01-01

Tuberculosis (TB) is one of the deadliest infectious diseases worldwide with a strong impact in developing countries. Mycobacterium tuberculosis, the etiological agent of TB, has a high capacity to evade the host immune system and establish a chronic, asymptomatic and latent infection. In a latent TB infection, persistent bacilli are present in a non-replicating dormant state within host granulomas. During reactivation, bacilli start replicating again leading to an active TB infection that can be highly contagious. Mycobacterial lipids and lipolytic enzymes are thought to play important physiological roles during dormancy and reactivation. The role of lipolytic enzymes in the physiology of M. tuberculosis and physiopathology of the disease will be discussed in this review, with an emphasis on the secreted or cell wall-associated, surface exposed lipolytic enzymes characterized to date. Studies on the localization, enzymatic activity and immunological properties of these enzymes highlighted their possible usefulness as new diagnostic markers in the fight against TB. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

R-Spondin1 expands Paneth cells and prevents dysbiosis induced by graft-versus-host disease

PubMed Central

Hayase, Eiko; Nakamura, Kiminori; Noizat, Clara; Ogasawara, Reiki; Ohigashi, Hiroyuki; Sugimoto, Rina; Matsuoka, Satomi; Ara, Takahide; Yokoyama, Emi; Yamakawa, Tomohiro; Ebata, Ko; Kondo, Takeshi; Aizawa, Tomoyasu; Ogura, Yoshitoshi; Hayashi, Tetsuya; Mori, Hiroshi; Tomizuka, Kazuma; Ayabe, Tokiyoshi

2017-01-01

The intestinal microbial ecosystem is actively regulated by Paneth cell–derived antimicrobial peptides such as α-defensins. Various disorders, including graft-versus-host disease (GVHD), disrupt Paneth cell functions, resulting in unfavorably altered intestinal microbiota (dysbiosis), which further accelerates the underlying diseases. Current strategies to restore the gut ecosystem are bacteriotherapy such as fecal microbiota transplantation and probiotics, and no physiological approach has been developed so far. In this study, we demonstrate a novel approach to restore gut microbial ecology by Wnt agonist R-Spondin1 (R-Spo1) or recombinant α-defensin in mice. R-Spo1 stimulates intestinal stem cells to differentiate to Paneth cells and enhances luminal secretion of α-defensins. Administration of R-Spo1 or recombinant α-defensin prevents GVHD-mediated dysbiosis, thus representing a novel and physiological approach at modifying the gut ecosystem to restore intestinal homeostasis and host–microbiota cross talk toward therapeutic benefits. PMID:29066578

Resistance to thermal stress in corals without changes in symbiont composition.

PubMed

Bellantuono, Anthony J; Hoegh-Guldberg, Ove; Rodriguez-Lanetty, Mauricio

2012-03-22

Discovering how corals can adjust their thermal sensitivity in the context of global climate change is important in understanding the long-term persistence of coral reefs. In this study, we showed that short-term preconditioning to higher temperatures, 3°C below the experimentally determined bleaching threshold, for a period of 10 days provides thermal tolerance for the symbiosis stability between the scleractinian coral, Acropora millepora and Symbiodinium. Based on genotypic analysis, our results indicate that the acclimatization of this coral species to thermal stress does not come down to simple changes in Symbiodinium and/or the bacterial communities that associate with reef-building corals. This suggests that the physiological plasticity of the host and/or symbiotic components appears to play an important role in responding to ocean warming. The further study of host and symbiont physiology, both of Symbiodinium and prokaryotes, is of paramount importance in the context of global climate change, as mechanisms for rapid holobiont acclimatization will become increasingly important to the long-standing persistence of coral reefs.

Metabolic host responses to infection by intracellular bacterial pathogens

PubMed Central

Eisenreich, Wolfgang; Heesemann, Jürgen; Rudel, Thomas; Goebel, Werner

2013-01-01

The interaction of bacterial pathogens with mammalian hosts leads to a variety of physiological responses of the interacting partners aimed at an adaptation to the new situation. These responses include multiple metabolic changes in the affected host cells which are most obvious when the pathogen replicates within host cells as in case of intracellular bacterial pathogens. While the pathogen tries to deprive nutrients from the host cell, the host cell in return takes various metabolic countermeasures against the nutrient theft. During this conflicting interaction, the pathogen triggers metabolic host cell responses by means of common cell envelope components and specific virulence-associated factors. These host reactions generally promote replication of the pathogen. There is growing evidence that pathogen-specific factors may interfere in different ways with the complex regulatory network that controls the carbon and nitrogen metabolism of mammalian cells. The host cell defense answers include general metabolic reactions, like the generation of oxygen- and/or nitrogen-reactive species, and more specific measures aimed to prevent access to essential nutrients for the respective pathogen. Accurate results on metabolic host cell responses are often hampered by the use of cancer cell lines that already exhibit various de-regulated reactions in the primary carbon metabolism. Hence, there is an urgent need for cellular models that more closely reflect the in vivo infection conditions. The exact knowledge of the metabolic host cell responses may provide new interesting concepts for antibacterial therapies. PMID:23847769

Studying Host-Pathogen Interactions In 3-D: Organotypic Models For Infectious Disease And Drug Development

NASA Technical Reports Server (NTRS)

Nickerson, Cheryl A.; Richter, Emily G.; Ott, C. Mark

2006-01-01

Representative, reproducible and high-throughput models of human cells and tissues are critical for a meaningful evaluation of host-pathogen interactions and are an essential component of the research developmental pipeline. The most informative infection models - animals, organ explants and human trials - are not suited for extensive evaluation of pathogenesis mechanisms and screening of candidate drugs. At the other extreme, more cost effective and accessible infection models such as conventional cell culture and static co-culture may not capture physiological and three-dimensional aspects of tissue biology that are important in assessing pathogenesis, and effectiveness and cytotoxicity of therapeutics. Our lab has used innovative bioengineering technology to establish biologically meaningful 3-D models of human tissues that recapitulate many aspects of the differentiated structure and function of the parental tissue in vivo, and we have applied these models to study infectious disease. We have established a variety of different 3-D models that are currently being used in infection studies - including small intestine, colon, lung, placenta, bladder, periodontal ligament, and neuronal models. Published work from our lab has shown that our 3-D models respond to infection with bacterial and viral pathogens in ways that reflect the infection process in vivo. By virtue of their physiological relevance, 3-D cell cultures may also hold significant potential as models to provide insight into the neuropathogenesis of HIV infection. Furthermore, the experimental flexibility, reproducibility, cost-efficiency, and high throughput platform afforded by these 3-D models may have important implications for the design and development of drugs with which to effectively treat neurological complications of HIV infection.

Life begins when the sea lion is ashore: microhabitat use by a louse living on a diving mammal host.

PubMed

Leonardi, M S; Crespo, E A; Vales, D G; Feijoo, M; Raga, J A; Aznar, F J

2012-08-01

Among Anoplura, the family Echinophthiriidae includes species that infest pinnipeds and otters. Previous evidence obtained from pinnipeds infested by echinophthiriids, specifically from seals, indicates that flippers are the preferred infestation sites, while lice from fur seals select areas in the pelage. We studied habitat selection of Antarctophthirus microchir on South American sea lion pups (Otaria flavescens Shaw, 1800) from Patagonia, Argentina, during the austral summer of 2009. We found a clear pattern of habitat selection: eggs are laid on the dorsal surface; nymphs 1 hatch there and then migrate to the belly, where they develop into adults and copulate; and then ovigerous females return to the dorsal surface. On the one hand, nymphs 1 are characterised by their low locomotory ability; therefore, the fact that they migrate as soon as they hatch suggests a clear pressure leading to microhabitat restriction. On the other hand, the described pattern of microhabitat selection seems to respond to the physiological requirements of each stage, which vary according to the physiological process considered, e.g. oviposition, morphogenesis, hatching and development. Accordingly, it appears that A. microchir would prefer the host's ventral area for development and copulation and the dorsal area for oviposition. However, the causes of this pattern are not clear, and many factors could be involved. Considering that sea lion pups periodically soak at high tides, and that prolonged immersion and very high humidity are known to be lethal for lice eggs, selecting the dorsal area would be advantageous for oviposition because it dries much faster. Furthermore, because humidity should be retained for longer periods on the ventral surface of the pup, wetter conditions on the sea lion would prevent desiccation of the nymphs in the very arid environment where O. flavescens breeds.

Calcium-mediated apoptosis in a plant hypersensitive disease resistance response.

PubMed

Levine, A; Pennell, R I; Alvarez, M E; Palmer, R; Lamb, C

1996-04-01

Avirulent pathogens elicit a battery of plant defenses, often accompanied by collapse of the challenged cells. In soybean cells, sustained accumulation of H2O2 from an oxidative burst cues localized host cell death. Such hypersensitive cell death appears to be an active process, but little is known about the mechanisms underlying cellular collapse. We show that H2O2 stimulates a rapid influx of Ca2+ into soybean cells, which activates a physiological cell death program resulting in the generation of large (approximately 50 kb) DNA fragments and cell corpse morphology--including cell shrinkage, plasma membrane blebbing and nuclear condensation--characteristic of apoptosis. In contrast, H2O2 induction of the cellular protectant gene glutathione S-transferase is Ca(2+)-independent. Apoptosis in soybean cells and leaf tissue was induced by avirulent Pseudomonas syringae pv. glycinea but was not observed at comparable stages of the compatible interaction with the isogenic virulent strain, which fails to elicit a hypersensitive response. Apoptosis was also observed at the onset of the hypersensitive response in Arabidopsis leaves inoculated with avirulent P. syringae pv. tomato and in tobacco cells treated with the fungal peptide cryptogein, which is involved in the induction of non-host resistance to Phytophthora cryptogea. These observations establish a signal function for Ca2+ downstream of the oxidative burst in the activation of a physiological cell death program in soybean cells that is similar to apoptosis in animals. That the characteristic cell corpse morphology is also induced in Arabidopsis and tobacco by different avirulence signals suggests that apoptosis may prove to be a common, but not necessarily ubiquitous, feature of incompatible plant-pathogen interactions. Emerging similarities between facets of hypersensitive disease resistance and the mammalian native immune system indicate that apoptosis is a widespread defence mechanism in eukaryotes.

Autophagy regulates UBC9 levels during viral-mediated tumorigenesis

PubMed Central

Mattoscio, Domenico; Casadio, Chiara; Miccolo, Claudia; Maffini, Fausto; Raimondi, Andrea; Tacchetti, Carlo; Gheit, Tarik; Tagliabue, Marta; Galimberti, Viviana E.; De Lorenzi, Francesca; Chiesa, Fausto; Ansarin, Mohssen; Tommasino, Massimo

2017-01-01

UBC9, the sole E2-conjugating enzyme required for SUMOylation, is a key regulator of essential cellular functions and, as such, is frequently altered in cancers. Along these lines, we recently reported that its expression gradually increases during early stages of human papillomavirus (HPV)-mediated cervical lesions transformation. However, a better understanding of how UBC9 is exploited by transforming viral oncoproteins is still needed. In the present study, we show that in human samples HPV drives UBC9 up-regulation also in very early steps of head and neck tumorigenesis, pointing to the important role for UBC9 in the HPV-mediated carcinogenic program. Moreover, using HPV-infected pre-cancerous tissues and primary human keratinocytes as the natural host of the virus, we investigate the pathological meaning and the cellular mechanisms responsible for UBC9 de-regulation in an oncoviral context. Our results show that UBC9 overexpression is promoted by transforming viral proteins to increase host cells’ resistance to apoptosis. In addition, ultrastuctural, pharmacological and genetic approaches crucially unveil that UBC9 is physiologically targeted by autophagy in human cells. However, the presence of HPV E6/E7 oncoproteins negatively impacts the autophagic process through selective inhibition of autophagosome-lysosome fusion, finally leading to p53 dependent UBC9 accumulation during viral-induced cellular transformation. Therefore, our study elucidates how UBC9 is manipulated by HPV oncoproteins, details the physiological mechanism by which UBC9 is degraded in cells, and identifies how HPV E6/E7 impact on autophagy. These findings point to UBC9 and autophagy as novel hallmarks of HPV oncogenesis, and open innovative avenues towards the treatment of HPV-related malignancies. PMID:28253371

Dominant negative retinoic acid receptor initiates tumor formation in mice.

PubMed

Kupumbati, Tara S; Cattoretti, Giorgio; Marzan, Christine; Farias, Eduardo F; Taneja, Reshma; Mira-y-Lopez, Rafael

2006-03-24

Retinoic acid suppresses cell growth and promotes cell differentiation, and pharmacological retinoic acid receptor (RAR) activation is anti-tumorigenic. This begs the question of whether chronic physiological RAR activation by endogenous retinoids is likewise anti-tumorigenic. To address this question, we generated transgenic mice in which expression of a ligand binding defective dominant negative RARalpha (RARalphaG303E) was under the control of the mouse mammary tumor virus (MMTV) promoter. The transgene was expressed in the lymphoid compartment and in the mammary epithelium. Observation of aging mice revealed that transgenic mice, unlike their wild type littermates, developed B cell lymphomas at high penetrance, with a median latency of 40 weeks. MMTV-RARalphaG303E lymphomas were high grade Pax-5+, surface H+L Ig negative, CD69+ and BCL6- and cytologically and phenotypically resembled human adult high grade (Burkitt's or lymphoblastic) lymphomas. We postulated that mammary tumors might arise after a long latency period as seen in other transgenic models of breast cancer. We tested this idea by transplanting transgenic epithelium into the cleared fat pads of wild type hosts, thus bypassing lymphomagenesis. At 17 months post-transplantation, a metastatic mammary adenocarcinoma developed in one of four transplanted glands whereas no tumors developed in sixteen of sixteen endogenous glands with wild type epithelium. These findings suggest that physiological RAR activity may normally suppress B lymphocyte and mammary epithelial cell growth and that global RAR inactivation is sufficient to initiate a stochastic process of tumor development requiring multiple transforming events. Our work makes available to the research community a new animal resource that should prove useful as an experimental model of aggressive sporadic lymphoma in immunologically uncompromised hosts. We anticipate that it may also prove useful as a model of breast cancer.

Characterization of the Bacterial Diversity in Indo-West Pacific Loliginid and Sepiolid Squid Light Organs

PubMed Central

Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A.; Willie, Shantell

2013-01-01

Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates. PMID:22885637

The effects of potato virus Y-derived virus small interfering RNAs of three biologically distinct strains on potato (Solanum tuberosum) transcriptome.

PubMed

Moyo, Lindani; Ramesh, Shunmugiah V; Kappagantu, Madhu; Mitter, Neena; Sathuvalli, Vidyasagar; Pappu, Hanu R

2017-07-17

Potato virus Y (PVY) is one of the most economically important pathogen of potato that is present as biologically distinct strains. The virus-derived small interfering RNAs (vsiRNAs) from potato cv. Russet Burbank individually infected with PVY-N, PVY-NTN and PVY-O strains were recently characterized. Plant defense RNA-silencing mechanisms deployed against viruses produce vsiRNAs to degrade homologous viral transcripts. Based on sequence complementarity, the vsiRNAs can potentially degrade host RNA transcripts raising the prospect of vsiRNAs as pathogenicity determinants in virus-host interactions. This study investigated the global effects of PVY vsiRNAs on the host potato transcriptome. The strain-specific vsiRNAs of PVY, expressed in high copy number, were analyzed in silico for their proclivity to target potato coding and non-coding RNAs using psRobot and psRNATarget algorithms. Functional annotation of target coding transcripts was carried out to predict physiological effects of the vsiRNAs on the potato cv. Russet Burbank. The downregulation of selected target coding transcripts was further validated using qRT-PCR. The vsiRNAs derived from biologically distinct strains of PVY displayed diversity in terms of absolute number, copy number and hotspots for siRNAs on their respective genomes. The vsiRNAs populations were derived with a high frequency from 6 K1, P1 and Hc-Pro for PVY-N, P1, Hc-Pro and P3 for PVY-NTN, and P1, 3' UTR and NIa for PVY-O genomic regions. The number of vsiRNAs that displayed interaction with potato coding transcripts and number of putative coding target transcripts were comparable between PVY-N and PVY-O, and were relatively higher for PVY-NTN. The most abundant target non-coding RNA transcripts for the strain specific PVY-derived vsiRNAs were found to be MIR821, 28S rRNA,18S rRNA, snoR71, tRNA-Met and U5. Functional annotation and qRT-PCR validation suggested that the vsiRNAs target genes involved in plant hormone signaling, genetic information processing, plant-pathogen interactions, plant defense and stress response processes in potato. The findings suggested that the PVY-derived vsiRNAs could act as a pathogenicity determinant and as a counter-defense strategy to host RNA silencing in PVY-potato interactions. The broad range of host genes targeted by PVY vsiRNAs in infected potato suggests a diverse role for vsiRNAs that includes suppression of host stress responses and developmental processes. The interactome scenario is the first report on the interaction between one of the most important Potyvirus genome-derived siRNAs and the potato transcripts.

Leaf morphophysiology of a Neotropical mistletoe is shaped by seasonal patterns of host leaf phenology.

PubMed

Scalon, Marina Corrêa; Rossatto, Davi Rodrigo; Domingos, Fabricius Maia Chaves Bicalho; Franco, Augusto Cesar

2016-04-01

Several mistletoe species are able to grow and reproduce on both deciduous and evergreen hosts, suggesting a degree of plasticity in their ability to cope with differences in intrinsic host functions. The aim of this study was to investigate the influence of host phenology on mistletoe water relations and leaf gas exchange. Mistletoe Passovia ovata parasitizing evergreen (Miconia albicans) hosts and P. ovata parasitizing deciduous (Byrsonima verbascifolia) hosts were sampled in a Neotropical savanna. Photosynthetic parameters, diurnal cycles of stomatal conductance, pre-dawn and midday leaf water potential, and stomatal anatomical traits were measured during the peak of the dry and wet seasons, respectively. P. ovata showed distinct water-use strategies that were dependent on host phenology. For P. ovata parasitizing the deciduous host, water use efficiency (WUE; ratio of photosynthetic rate to transpirational water loss) was 2-fold lower in the dry season than in the wet season; in contrast, WUE was maintained at the same level during the wet and dry seasons in P. ovata parasitizing the evergreen host. Generally, mistletoe and host diurnal cycles of stomatal conductance were linked, although there were clear differences in leaf water potential, with mistletoe showing anisohydric behaviour and the host showing isohydric behaviour. Compared to mistletoes attached to evergreen hosts, those parasitizing deciduous hosts had a 1.4-fold lower stomatal density and 1.2-fold wider stomata on both leaf surfaces, suggesting that the latter suffered less intense drought stress. This is the first study to show morphophysiological differences in the same mistletoe species parasitizing hosts of different phenological groups. Our results provide evidence that phenotypical plasticity (anatomical and physiological) might be essential to favour the use of a greater range of hosts.

Influence of temperature on patch residence time in parasitoids: physiological and behavioural mechanisms

NASA Astrophysics Data System (ADS)

Moiroux, Joffrey; Abram, Paul K.; Louâpre, Philippe; Barrette, Maryse; Brodeur, Jacques; Boivin, Guy

2016-04-01

Patch time allocation has received much attention in the context of optimal foraging theory, including the effect of environmental variables. We investigated the direct role of temperature on patch time allocation by parasitoids through physiological and behavioural mechanisms and its indirect role via changes in sex allocation and behavioural defences of the hosts. We compared the influence of foraging temperature on patch residence time between an egg parasitoid, Trichogramma euproctidis, and an aphid parasitoid, Aphidius ervi. The latter attacks hosts that are able to actively defend themselves, and may thus indirectly influence patch time allocation of the parasitoid. Patch residence time decreased with an increase in temperature in both species. The increased activity levels with warming, as evidenced by the increase in walking speed, partially explained these variations, but other mechanisms were involved. In T. euproctidis, the ability to externally discriminate parasitised hosts decreased at low temperature, resulting in a longer patch residence time. Changes in sex allocation with temperature did not explain changes in patch time allocation in this species. For A. ervi, we observed that aphids frequently escaped at intermediate temperature and defended themselves aggressively at high temperature, but displayed few defence mechanisms at low temperature. These defensive behaviours resulted in a decreased patch residence time for the parasitoid and partly explained the fact that A. ervi remained for a shorter time at the intermediate and high temperatures than at the lowest temperature. Our results suggest that global warming may affect host-parasitoid interactions through complex mechanisms including both direct and indirect effects on parasitoid patch time allocation.

Leptospira interrogans lpxD Homologue Is Required for Thermal Acclimatization and Virulence

PubMed Central

Eshghi, Azad; Henderson, Jeremy; Trent, M. Stephen

2015-01-01

Leptospirosis is an emerging disease with an annual occurrence of over 1 million human cases worldwide. Pathogenic Leptospira bacteria are maintained in zoonotic cycles involving a diverse array of mammals, with the capacity to survive outside the host in aquatic environments. Survival in the diverse environments encountered by Leptospira likely requires various adaptive mechanisms. Little is known about Leptospira outer membrane modification systems, which may contribute to the capacity of these bacteria to successfully inhabit and colonize diverse environments and animal hosts. Leptospira bacteria carry two genes annotated as UDP-3-O-[3-hydroxymyristoyl] glucosamine N-acyltransferase genes (la0512 and la4326 [lpxD1 and lpxD2]) that in other bacteria are involved in the early steps of biosynthesis of lipid A, the membrane lipid anchor of lipopolysaccharide. Inactivation of only one of these genes, la0512/lpxD1, imparted sensitivity to the host physiological temperature (37°C) and rendered the bacteria avirulent in an animal infection model. Polymyxin B sensitivity assays revealed compromised outer membrane integrity in the lpxD1 mutant at host physiological temperature, but structural analysis of lipid A in the mutant revealed only minor changes in the lipid A moiety compared to that found in the wild-type strain. In accordance with this, an in trans complementation restored the phenotypes to a level comparable to that of the wild-type strain. These results suggest that the gene annotated as lpxD1 in Leptospira interrogans plays an important role in temperature adaptation and virulence in the animal infection model. PMID:26283339

Metagenomic analysis of nitrate-reducing bacteria in the oral cavity: implications for nitric oxide homeostasis.

PubMed

Hyde, Embriette R; Andrade, Fernando; Vaksman, Zalman; Parthasarathy, Kavitha; Jiang, Hong; Parthasarathy, Deepa K; Torregrossa, Ashley C; Tribble, Gena; Kaplan, Heidi B; Petrosino, Joseph F; Bryan, Nathan S

2014-01-01

The microbiota of the human lower intestinal tract helps maintain healthy host physiology, for example through nutrient acquisition and bile acid recycling, but specific positive contributions of the oral microbiota to host health are not well established. Nitric oxide (NO) homeostasis is crucial to mammalian physiology. The recently described entero-salivary nitrate-nitrite-nitric oxide pathway has been shown to provide bioactive NO from dietary nitrate sources. Interestingly, this pathway is dependent upon oral nitrate-reducing bacteria, since humans lack this enzyme activity. This pathway appears to represent a newly recognized symbiosis between oral nitrate-reducing bacteria and their human hosts in which the bacteria provide nitrite and nitric oxide from nitrate reduction. Here we measure the nitrate-reducing capacity of tongue-scraping samples from six healthy human volunteers, and analyze metagenomes of the bacterial communities to identify bacteria contributing to nitrate reduction. We identified 14 candidate species, seven of which were not previously believed to contribute to nitrate reduction. We cultivated isolates of four candidate species in single- and mixed-species biofilms, revealing that they have substantial nitrate- and nitrite-reduction capabilities. Colonization by specific oral bacteria may thus contribute to host NO homeostasis by providing nitrite and nitric oxide. Conversely, the lack of specific nitrate-reducing communities may disrupt the nitrate-nitrite-nitric oxide pathway and lead to a state of NO insufficiency. These findings may also provide mechanistic evidence for the oral systemic link. Our results provide a possible new therapeutic target and paradigm for NO restoration in humans by specific oral bacteria.

Metagenomic Analysis of Nitrate-Reducing Bacteria in the Oral Cavity: Implications for Nitric Oxide Homeostasis

PubMed Central

Hyde, Embriette R.; Andrade, Fernando; Vaksman, Zalman; Parthasarathy, Kavitha; Jiang, Hong; Parthasarathy, Deepa K.; Torregrossa, Ashley C.; Tribble, Gena; Kaplan, Heidi B.; Petrosino, Joseph F.; Bryan, Nathan S.

2014-01-01

The microbiota of the human lower intestinal tract helps maintain healthy host physiology, for example through nutrient acquisition and bile acid recycling, but specific positive contributions of the oral microbiota to host health are not well established. Nitric oxide (NO) homeostasis is crucial to mammalian physiology. The recently described entero-salivary nitrate-nitrite-nitric oxide pathway has been shown to provide bioactive NO from dietary nitrate sources. Interestingly, this pathway is dependent upon oral nitrate-reducing bacteria, since humans lack this enzyme activity. This pathway appears to represent a newly recognized symbiosis between oral nitrate-reducing bacteria and their human hosts in which the bacteria provide nitrite and nitric oxide from nitrate reduction. Here we measure the nitrate-reducing capacity of tongue-scraping samples from six healthy human volunteers, and analyze metagenomes of the bacterial communities to identify bacteria contributing to nitrate reduction. We identified 14 candidate species, seven of which were not previously believed to contribute to nitrate reduction. We cultivated isolates of four candidate species in single- and mixed-species biofilms, revealing that they have substantial nitrate- and nitrite-reduction capabilities. Colonization by specific oral bacteria may thus contribute to host NO homeostasis by providing nitrite and nitric oxide. Conversely, the lack of specific nitrate-reducing communities may disrupt the nitrate-nitrite-nitric oxide pathway and lead to a state of NO insufficiency. These findings may also provide mechanistic evidence for the oral systemic link. Our results provide a possible new therapeutic target and paradigm for NO restoration in humans by specific oral bacteria. PMID:24670812

Histophagous ciliate Pseudocollinia brintoni and bacterial assemblage interaction with krill Nyctiphanes simplex. II. Host responses.

PubMed

Gómez-Gutiérrez, Jaime; Angel-Rodríguez, Jorge A; Tremblay, Nelly; Zenteno-Savín, Tania; Aguilar-Méndez, Mario J; López-Cortés, Alejandro; Robinson, Carlos J

2015-10-27

Unlike decapod crustaceans of commercial interest, the krill defense system and its response to parasites and pathogens is virtually unknown. Histophagous ciliates of the genus Pseudocollinia interact with at least 7 krill species in the northeastern Pacific. Although they can cause epizootic events, the physiology of the histophagous ciliate-host interaction and krill (host) defenses remain unknown. From 1 oceanographic survey along the southwestern coast of the Baja California Peninsula near Bahía Magdalena and 2 in the Gulf of California, we investigated parasitoid-host physiological responses (fatty acid and oxidative stress indicators) of the subtropical krill Nyctiphanes simplex infected with the ciliate P. brintoni. All life stages of P. brintoni were associated with opportunistic bacterial assemblages that have not been explicitly investigated in other Pseudocollinia species (P. beringensis, P. oregonensis, and P. similis). Parasitoid ciliates exclusively infected adult females, which showed increased lipid content during gonad development. As the infection progressed, omega-3 eicosapentaenoic and docosahexaenoic fatty acids, which may act as energy sources to produce high numbers of ciliate transmission stages, were quickly depleted. Antioxidant enzymes, components of the crustacean defense system, varied throughout infection, but without inhibiting Pseudocollinia infection, i.e. higher levels of lipid oxidative damage were detected in late stages of infection. The ineffective response of the krill antioxidant defense system against histophagous ciliates and the bacteria associated with the ciliates suggests that Pseudocollinia ciliates are functionally analogous to krill predators and may have a strong influence on the population dynamics of krill.

Evolution and Biogeography of Haemonchus contortus: Linking Faunal Dynamics in Space and Time.

PubMed

Hoberg, E P; Zarlenga, D S

2016-01-01

History is the foundation that informs about the nuances of faunal assembly that are essential in understanding the dynamic nature of the host-parasite interface. All of our knowledge begins and ends with evolution, ecology and biogeography, as these interacting facets determine the history of biodiverse systems. These components, relating to Haemonchus, can inform about the complex history of geographical distribution, host association and the intricacies of host-parasite associations that are played out in physiological and behavioural processes that influence the potential for disease and our capacity for effective control in a rapidly changing world. Origins and evolutionary diversification among species of the genus Haemonchus and Haemonchus contortus occurred in a complex crucible defined by shifts in environmental structure emerging from cycles of climate change and ecological perturbation during the late Tertiary and through the Quaternary. A history of sequential host colonization associated with waves of dispersal bringing assemblages of ungulates from Eurasia into Africa and processes emerging from ecosystems in collision and faunal turnover defined the arena for radiation among 12 recognized species of Haemonchus. Among congeners, the host range for H. contortus is exceptionally broad, including species among artiodactyls of 40 genera representing 5 families (and within 12 tribes of Bovidae). Broad host range is dramatically reflected in the degree to which translocation, introduction and invasion with host switching, has characterized an expanding distribution over time in North America, South America, southern Eurasia, Australia and New Zealand, coincidental with agriculture, husbandry and global colonization by human populations driven particularly by European exploration after the 1500s. African origins in xeric to mesic habitats of the African savannah suggest that historical constraints linked to ecological adaptations (tolerances and developmental thresholds defined by temperature and humidity for larval stages) will be substantial determinants in the potential outcomes for widespread geographical and host colonization which are predicted to unfold over the coming century. Insights about deeper evolutionary events, ecology and biogeography are critical as understanding history informs us about the possible range of responses in complex systems under new regimes of environmental forcing, especially, in this case, ecological perturbation linked to climate change. A deeper history of perturbation is relevant in understanding contemporary systems that are now strongly structured by events of invasion and colonization. The relaxation of abiotic and biotic controls on the occurrence of H. contortus, coincidental with inception and dissemination of anthelmintic resistance may be synergistic, serving to exacerbate challenges to control parasites or to limit the socioeconomic impacts of infection that can influence food security and availability. Studies of haemonchine nematodes contribute directly to an expanding model about the nature of diversity and the evolutionary trajectories for faunal assembly among complex host-parasite systems across considerable spatial and temporal scales. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predictors of host specificity among behavior-manipulating parasites.

PubMed

Fredensborg, B L

2014-07-01

A trade-off between resource-specialization and the breadth of the ecological niche is one of the most fundamental biological characteristics. A true generalist (Jack-of-all-trades) displays a broad ecological niche with little resource specialization while the opposite is true for a resource-specialist that has a restricted ecological niche that it masters. Parasites that manipulate hosts' behavior are often thought to represent resource-specialists based on a few spectacular examples of manipulation of the host's behavior. However, the determinants of which, and how many, hosts a manipulating parasite can exploit (i.e., niche breadth) are basically unknown. Here, I present an analysis based on published records of the use of hosts by 67 species from 38 genera of helminths inducing parasite increased trophic transmission, a widespread strategy of parasites that has been reported from many taxa of parasites and hosts. Using individual and multivariate analyses, I examined the effect of the host's and parasite's taxonomy, location of the parasite in the host, type of behavioral change, and the effect of debilitation on host-specificity, measured as the mean taxonomic relatedness of hosts that a parasite can manipulate. Host-specificity varied substantially across taxa suggesting great variation in the level of resource-specialization among manipulating parasites. Location of the parasite, level of debilitation, and type of host were all significant predictors of host-specificity. More specifically, hosts' behavioral modification that involves interaction with the central nervous system presumably restricts parasites to more closely related hosts than does manipulation of the host's behavior via debilitation of the host's physiology. The results of the analysis suggest that phylogenetic relatedness of hosts is a useful measure of host-specificity in comparative studies of the complexity of interactions taking place between manipulating parasites and their hosts. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Short chain fatty acid production and glucose responses by methane producers

USDA-ARS?s Scientific Manuscript database

Fermentation by gut microbiota has been linked to physiologic responses in the host. Methanogenic gut bacteria may remove more carbon from indigestible food matrices especially poorly digested carbohydrates. We sought to assess the effects of methane production on short chain fatty acid (SCFA) con...

Companion animals symposium: role of microbes in canine and feline health.

PubMed

Kil, D Y; Swanson, K S

2011-05-01

Whether in an ocean reef, a landfill, or a gastrointestinal tract (GIT), invisible communities of highly active and adaptable microbes prosper. Over time, mammals have developed a symbiosis with microbes that are important inhabitants not only in the GIT, but also in the mouth, skin, and urogenital tract. In the GIT, the number of commensal microbes exceeds the total number of host cells by at least 10 times. The GIT microbes play a critical role in nutritional, developmental, defensive, and physiologic processes in the host. Recent evidence also suggests a role of GIT microbes in metabolic phenotype and disease risk (e.g., obesity, metabolic syndrome) of the host. Proper balance is a key to maintaining GIT health. Balanced microbial colonization is also important for other body regions such as the oral cavity, the region with the greatest prevalence of disease in dogs and cats. A significant obstruction to studying microbial populations has been the lack of tools to identify and quantify microbial communities accurately and efficiently. Most of the current knowledge of microbial populations has been established by traditional cultivation methods that are not only laborious, time-consuming, and often inaccurate, but also greatly limited in scope. However, recent advances in molecular-based techniques have resulted in a dramatic improvement in studying microbial communities. These DNA-based high-throughput technologies have enabled us to more clearly characterize the identity and metabolic activity of microbes living in the host and their association with health and diseases. Despite this recent progress, however, published data pertaining to microbial communities of dogs and cats are still lacking in comparison with data in humans and other animals. More research is required to provide a more detailed description of the canine and feline microbiome and its role in health and disease.

Twin Attributes of Tyrosyl-tRNA Synthetase of Leishmania donovani: A HOUSEKEEPING PROTEIN TRANSLATION ENZYME AND A MIMIC OF HOST CHEMOKINE.

PubMed

Anand, Sneha; Madhubala, Rentala

2016-08-19

Aminoacyl-tRNA synthetases (aaRSs) are housekeeping enzymes essential for protein synthesis. Apart from their parent aminoacylation activity, several aaRSs perform non-canonical functions in diverse biological processes. The present study explores the twin attributes of Leishmania tyrosyl-tRNA synthetase (LdTyrRS) namely, aminoacylation, and as a mimic of host CXC chemokine. Leishmania donovani is a protozoan parasite. Its genome encodes a single copy of tyrosyl-tRNA synthetase. We first tested the canonical aminoacylation role of LdTyrRS. The recombinant protein was expressed, and its kinetic parameters were determined by aminoacylation assay. To study the physiological role of LdTyrRS in Leishmania, gene deletion mutations were attempted via targeted gene replacement. The heterozygous mutants showed slower growth kinetics and exhibited attenuated virulence. LdTyrRS appears to be an essential gene as the chromosomal null mutants did not survive. Our data also highlights the non-canonical function of L. donovani tyrosyl-tRNA synthetase. We show that LdTyrRS protein is present in the cytoplasm and exits from the parasite cytoplasm into the extracellular medium. The released LdTyrRS functions as a neutrophil chemoattractant. We further show that LdTyrRS specifically binds to host macrophages with its ELR (Glu-Leu-Arg) peptide motif. The ELR-CXCR2 receptor interaction mediates this binding. This interaction triggers enhanced secretion of the proinflammatory cytokines TNF-α and IL-6 by host macrophages. Our data indicates a possible immunomodulating role of LdTyrRS in Leishmania infection. This study provides a platform to explore LdTyrRS as a potential target for drug development. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Identification of the main venom protein components of Aphidius ervi, a parasitoid wasp of the aphid model Acyrthosiphon pisum.

PubMed

Colinet, Dominique; Anselme, Caroline; Deleury, Emeline; Mancini, Donato; Poulain, Julie; Azéma-Dossat, Carole; Belghazi, Maya; Tares, Sophie; Pennacchio, Francesco; Poirié, Marylène; Gatti, Jean-Luc

2014-05-06

Endoparasitoid wasps are important natural enemies of the widely distributed aphid pests and are mainly used as biological control agents. However, despite the increased interest on aphid interaction networks, only sparse information is available on the factors used by parasitoids to modulate the aphid physiology. Our aim was here to identify the major protein components of the venom injected at oviposition by Aphidius ervi to ensure successful development in its aphid host, Acyrthosiphon pisum. A combined large-scale transcriptomic and proteomic approach allowed us to identify 16 putative venom proteins among which three γ-glutamyl transpeptidases (γ-GTs) were by far the most abundant. Two of the γ-GTs most likely correspond to alleles of the same gene, with one of these alleles previously described as involved in host castration. The third γ-GT was only distantly related to the others and may not be functional owing to the presence of mutations in the active site. Among the other abundant proteins in the venom, several were unique to A. ervi such as the molecular chaperone endoplasmin possibly involved in protecting proteins during their secretion and transport in the host. Abundant transcripts encoding three secreted cystein-rich toxin-like peptides whose function remains to be explored were also identified. Our data further support the role of γ-GTs as key players in A. ervi success on aphid hosts. However, they also evidence that this wasp venom is a complex fluid that contains diverse, more or less specific, protein components. Their characterization will undoubtedly help deciphering parasitoid-aphid and parasitoid-aphid-symbiont interactions. Finally, this study also shed light on the quick evolution of venom components through processes such as duplication and convergent recruitment of virulence factors between unrelated organisms.

Salivary Histatin 5 Is an Inhibitor of Both Host and Bacterial Enzymes Implicated in Periodontal Disease

PubMed Central

Gusman, Heloisa; Travis, James; Helmerhorst, Eva J.; Potempa, Jan; Troxler, Robert F.; Oppenheim, Frank G.

2001-01-01

One of the salient features of periodontitis and gingivitis is the increase in the levels of bacterial and host-derived proteolytic enzymes in oral inflammatory exudates. This study evaluated the potential of histatin 5, a 24-residue histidine-rich salivary antimicrobial protein, to inhibit these enzymes. Using biotinylated gelatin as a substrate, histatin 5 was found to inhibit the activity of the host matrix metalloproteinases MMP-2 and MMP-9 with 50% inhibitory concentrations (IC50s) of 0.57 and 0.25 μM, respectively. To localize the domain responsible for this inhibition, three peptides containing different regions of histatin 5 were synthesized and tested as inhibitors of MMP-9. Peptides comprising residues 1 to 14 and residues 4 to 15 of histatin 5 showed much lower inhibitory activities (IC50, 21.4 and 20.5 μM, respectively), while a peptide comprising residues 9 to 22 showed identical activity to histatin 5 against MMP-9. These results point to a functional domain localized in the C-terminal part of histatin 5. To evaluate the effect of histatin 5 on bacterial proteases, a detailed characterization of histatin 5 inhibition of gingipains from Porphyromonas gingivalis was carried out using purified Arg- and Lys-specific enzymes. Kinetic analysis of the inhibition of the Arg-gingipain revealed that histatin 5 is a competitive inhibitor, affecting only the Km with a Ki of 15 μM. In contrast, inhibition of Lys-gingipain affected both the Km and Vmax, suggesting that both competitive and noncompetitive competitive processes underlie this inhibition. The inhibitory activity of histatin 5 against host and bacterial proteases at physiological concentrations points to a new potential biological function of histatin in the oral cavity. PMID:11179305

Role of Ergothioneine in Microbial Physiology and Pathogenesis

PubMed Central

Cumming, Bridgette M.; Chinta, Krishna C.; Reddy, Vineel P.

2018-01-01

Abstract Significance: L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria, and some fungi. In contrast to other low-molecular-weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables the survival of microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection. Recent Advances: Ergothioneine has been reported to maintain bioenergetic homeostasis in Mtb and protect Mtb against oxidative stresses, thereby enhancing the virulence of Mtb in a mouse model. Furthermore, ergothioneine augments the resistance of Mtb to current frontline anti-TB drugs. Recently, an opportunistic fungus, Aspergillus fumigatus, which infects immunocompromised individuals, has been found to produce ergothioneine, which is important in conidial health and germination, and contributes to the fungal resistance against redox stresses. Critical Issues: The molecular mechanisms of the functions of ergothioneine in microbial physiology and pathogenesis are poorly understood. It is currently not known if ergothioneine is used in detoxification or antioxidant enzymatic pathways. As ergothioneine is involved in bioenergetic and redox homeostasis and antibiotic susceptibility of Mtb, it is of utmost importance to advance our understanding of these mechanisms. Future Directions: A clear understanding of the role of ergothioneine in microbes will advance our knowledge of how this thione enhances microbial virulence and resistance to the host's defense mechanisms to avoid complete eradication. Antioxid. Redox Signal. 28, 431–444. PMID:28791878

Multivariate inference of pathway activity in host immunity and response to therapeutics

PubMed Central

Goel, Gautam; Conway, Kara L.; Jaeger, Martin; Netea, Mihai G.; Xavier, Ramnik J.

2014-01-01

Developing a quantitative view of how biological pathways are regulated in response to environmental factors is central for understanding of disease phenotypes. We present a computational framework, named Multivariate Inference of Pathway Activity (MIPA), which quantifies degree of activity induced in a biological pathway by computing five distinct measures from transcriptomic profiles of its member genes. Statistical significance of inferred activity is examined using multiple independent self-contained tests followed by a competitive analysis. The method incorporates a new algorithm to identify a subset of genes that may regulate the extent of activity induced in a pathway. We present an in-depth evaluation of specificity, robustness, and reproducibility of our method. We benchmarked MIPA's false positive rate at less than 1%. Using transcriptomic profiles representing distinct physiological and disease states, we illustrate applicability of our method in (i) identifying gene–gene interactions in autophagy-dependent response to Salmonella infection, (ii) uncovering gene–environment interactions in host response to bacterial and viral pathogens and (iii) identifying driver genes and processes that contribute to wound healing and response to anti-TNFα therapy. We provide relevant experimental validation that corroborates the accuracy and advantage of our method. PMID:25147207

“I Am I and My Bacterial Circumstances”: Linking Gut Microbiome, Neurodevelopment, and Depression

PubMed Central

Lima-Ojeda, Juan M.; Rupprecht, Rainer; Baghai, Thomas C.

2017-01-01

Recently, there has been renewed interest in the role played by microbiome in both human health and human disease. A correct equilibrium between the human host and their microorganisms is important for an appropriate physiological function. Extensive research has shown that microbes that inhabit the gastrointestinal tract—or gut microbiota—are involved not only in both nutritive and digestive activities but also in immunological processes. Moreover, the gut microbiome influences both central nervous system and energy homeostasis. An altered gut microbiome has been associated with the pathophysiology of different diseases, including neuropsychiatric disorders. Apparently, both environmental—diet, exposition to antibiotics, and infections—and host-genetic factors have a strong influence on gut microbiome, modulating the risk for neuropsychiatric illness. Also, early life disruption of the microbiome–gut–brain (MGB) axis has been associated with an increased risk of developing depression later in life, suggesting a link between gut microbiome, neurodevelopment, and depression. This review aims to contribute to this growing area of research by exploring the role played by the gut microbiome in neurodevelopment and in the etiology of the depressive syndrome, including nutritional, immunological, and energy homeostasis approaches. PMID:28878696

Gut microbiome and the risk factors in central nervous system autoimmunity.

PubMed

Ochoa-Repáraz, Javier; Kasper, Lloyd H

2014-11-17

Humans are colonized after birth by microbial organisms that form a heterogeneous community, collectively termed microbiota. The genomic pool of this macro-community is named microbiome. The gut microbiota is essential for the complete development of the immune system, representing a binary network in which the microbiota interact with the host providing important immune and physiologic function and conversely the bacteria protect themselves from host immune defense. Alterations in the balance of the gut microbiome due to a combination of environmental and genetic factors can now be associated with detrimental or protective effects in experimental autoimmune diseases. These gut microbiome alterations can unbalance the gastrointestinal immune responses and influence distal effector sites leading to CNS disease including both demyelination and affective disorders. The current range of risk factors for MS includes genetic makeup and environmental elements. Of interest to this review is the consistency between this range of MS risk factors and the gut microbiome. We postulate that the gut microbiome serves as the niche where different MS risk factors merge, thereby influencing the disease process. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Iron-Binding Protein Degradation by Cysteine Proteases of Naegleria fowleri.

PubMed

Martínez-Castillo, Moisés; Ramírez-Rico, Gerardo; Serrano-Luna, Jesús; Shibayama, Mineko

2015-01-01

Naegleria fowleri causes acute and fulminant primary amoebic meningoencephalitis. This microorganism invades its host by penetrating the olfactory mucosa and then traveling up the mesaxonal spaces and crossing the cribriform plate; finally, the trophozoites invade the olfactory bulbs. During its invasion, the protozoan obtains nutrients such as proteins, lipids, carbohydrates, and cationic ions (e.g., iron, calcium, and sodium) from the host. However, the mechanism by which these ions are obtained, particularly iron, is poorly understood. In the present study, we evaluated the ability of N. fowleri to degrade iron-binding proteins, including hololactoferrin, transferrin, ferritin, and hemoglobin. Zymography assays were performed for each substrate under physiological conditions (pH 7 at 37°C) employing conditioned medium (CM) and total crude extracts (TCEs) of N. fowleri. Different degradation patterns with CM were observed for hololactoferrin, transferrin, and hemoglobin; however, CM did not cause ferritin degradation. In contrast, the TCEs degraded only hololactoferrin and transferrin. Inhibition assays revealed that cysteine proteases were involved in this process. Based on these results, we suggest that CM and TCEs of N. fowleri degrade iron-binding proteins by employing cysteine proteases, which enables the parasite to obtain iron to survive while invading the central nervous system.

Iron-Binding Protein Degradation by Cysteine Proteases of Naegleria fowleri

PubMed Central

Ramírez-Rico, Gerardo; Serrano-Luna, Jesús; Shibayama, Mineko

2015-01-01

Naegleria fowleri causes acute and fulminant primary amoebic meningoencephalitis. This microorganism invades its host by penetrating the olfactory mucosa and then traveling up the mesaxonal spaces and crossing the cribriform plate; finally, the trophozoites invade the olfactory bulbs. During its invasion, the protozoan obtains nutrients such as proteins, lipids, carbohydrates, and cationic ions (e.g., iron, calcium, and sodium) from the host. However, the mechanism by which these ions are obtained, particularly iron, is poorly understood. In the present study, we evaluated the ability of N. fowleri to degrade iron-binding proteins, including hololactoferrin, transferrin, ferritin, and hemoglobin. Zymography assays were performed for each substrate under physiological conditions (pH 7 at 37°C) employing conditioned medium (CM) and total crude extracts (TCEs) of N. fowleri. Different degradation patterns with CM were observed for hololactoferrin, transferrin, and hemoglobin; however, CM did not cause ferritin degradation. In contrast, the TCEs degraded only hololactoferrin and transferrin. Inhibition assays revealed that cysteine proteases were involved in this process. Based on these results, we suggest that CM and TCEs of N. fowleri degrade iron-binding proteins by employing cysteine proteases, which enables the parasite to obtain iron to survive while invading the central nervous system. PMID:26090408

Diet regulates liver autophagy differentially in murine acute Trypanosoma cruzi infection

PubMed Central

Lizardo, Kezia; Almonte, Vanessa; Law, Calvin; Aiyyappan, Janeesh Plakkal; Cui, Min-Hui; Nagajyothi, Jyothi F

2017-01-01

Chagas disease is a tropical parasitic disease caused by the protozoan Trypanosoma cruzi, which affects about 10 million people in its endemic regions of Latin America. After the initial acute stage of infection, 60–80% of infected individuals remain asymptomatic for several years to a lifetime; however, the rest develop the debilitating symptomatic stage, which affects the nervous system, digestive system and heart. The challenges of Chagas disease have become global due to immigration. Despite well documented dietary changes accompanying immigration, as well as a transition to a western style diet in the Chagas endemic regions, the role of host metabolism in the pathogenesis of Chagas disease remains underexplored. We have previously used a mouse model to show that host diet is a key factor regulating cardiomyopathy in Chagas disease. In this study we investigated the effect of a high fat diet on liver morphology and physiology, lipid metabolism, immune signaling, energy homeostasis, and stress responses in the murine model of acute T. cruzi infection. Our results indicate that in T. cruzi infected mice diet differentially regulates several liver processes, including autophagy, a stress response mechanism, with corresponding implications for human Chagas disease patients. PMID:27987056

Stress Proteins and Initiation of Immune Response: Chaperokine activity of Hsp72

PubMed Central

Asea, Alexzander

2006-01-01

From its original description as solely an intracellular molecular chaperone, heat shock proteins have now been shown to function as initiators of the host's immune response. Although the exact mechanism by which intracellular heat shock proteins leave cells is still incompletely understood, recent work from several labs suggest that heat shock proteins are released by both passive (necrotic) and active (physiological) mechanisms. Binding to specific surface receptors is a prerequisite for the initiation of an immune response. To date, several cell surface proteins have been described as the receptor for seventy kilo-Dalton heat shock protein (Hsp70) including Toll-like receptors 2 and 4 with their cofactor CD14, the scavenger receptor CD36, the low-density lipoprotein receptor-related protein CD91, the C-type lectin receptor LOX-1, and another member of the scavenger super-family SR-A plus the co-stimulatory molecule, CD40. Binding of Hsp70 to these surface receptors specifically activates intracellular signaling cascades, which in turn exert immunoregulatory effector functions; a process known as the chaperokine activity of Hsp70. This review will highlight recent advances in understanding the mechanism by which Hsp70 initiates the host's immune response. PMID:16385842

Stress proteins and initiation of immune response: chaperokine activity of hsp72.

PubMed

Asea, Alexzander

2005-01-01

From its original description as solely an intracellular molecular chaperone, heat shock proteins have now been shown to function as initiators of the host's immune response. Although the exact mechanism by which intracellular heat shock proteins leave cells is still incompletely understood, recent work from several labs suggest that heat shock proteins are released by both passive (necrotic) and active (physiological) mechanisms. Binding to specific surface receptors is a prerequisite for the initiation of an immune response. To date, several cell surface proteins have been described as the receptor for seventy kilo-Dalton heat shock protein (Hsp70) including Toll-like receptors 2 and 4 with their cofactor CD14, the scavenger receptor CD36, the low-density lipoprotein receptor-related protein CD91, the C-type lectin receptor LOX-1, and another member of the scavenger super-family SR-A plus the co-stimulatory molecule, CD40. Binding of Hsp70 to these surface receptors specifically activates intracellular signaling cascades, which in turn exert immunoregulatory effector functions; a process known as the chaperokine activity of Hsp70. This review will highlight recent advances in understanding the mechanism by which Hsp70 initiates the host's immune response.

Unraveling Vital Effects: Photosynthesis of Symbiotic Algae in Foraminifera Hosts

NASA Astrophysics Data System (ADS)

Fish, C.; Phelps, S. R.; Goes, J. I.; Hoenisch, B.

2015-12-01

B/Ca and boron isotope proxies recorded in the calcium carbonate shells of planktic foraminifera are sensitive to seawater acidity. We seek to understand how the biology of the organism affects the geochemical signals, as planktic foraminifera shells differ in their chemical composition from inorganic calcite and also between foraminifer species. These differences are most likely related to physiological processes like respiration, calcification, and photosynthesis in symbiont-bearing foraminifera. The modifications of geochemical signals by these biological parameters are termed vital effects. Our study is based on the hypothesis that the B/Ca and δ11B offsets observed in planktic foraminifer shells are primarily due to the photosynthetic activity of their symbionts, which may elevate the microenvironmental pH to different degrees in different foraminifer species. Using fast repetition rate fluorometry, chlorophyll α analyses and symbiont counts, we investigated the symbiont-photosynthetic activity associated with three foraminifera species - Globigerinoides ruber, G. sacculifer, and Orbulina universa. Boron proxy systematics in these species suggest that photosynthetic activity should be greater in G. ruber compared to G. sacculifer and O. universa, but this is not confirmed by our study. While symbiont photosynthesis undoubtedly explains microenvironmental pH-elevation and boron proxy systematics in symbiont-bearing compared to symbiont-barren foraminifer species, additional processes must be responsible for the boron geochemical offsets between symbiont-bearing species. Respiration of the symbiont-host association and the calcification process are most likely candidates that require further analysis. Our study highlights the potential danger of misinterpreting geochemical signals in biological organisms when the biology of the organism in question is not entirely understood.

The potential and prospects of proximal remote sensing of arthropod pests.

PubMed

Nansen, Christian

2016-04-01

Bench-top or proximal remote sensing applications are widely used as part of quality control and machine vision systems in commercial operations. In addition, these technologies are becoming increasingly important in insect systematics and studies of insect physiology and pest management. This paper provides a review and discussion of how proximal remote sensing may contribute valuable quantitative information regarding identification of species, assessment of insect responses to insecticides, insect host responses to parasitoids and performance of biological control agents. The future role of proximal remote sensing is discussed as an exciting path for novel paths of multidisciplinary research among entomologists and scientists from a wide range of other disciplines, including image processing engineers, medical engineers, research pharmacists and computer scientists. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

The Impact of Climate Trends on a Tick Affecting Public Health: A Retrospective Modeling Approach for Hyalomma marginatum (Ixodidae)

PubMed Central

Estrada-Peña, Agustín; de la Fuente, José; Latapia, Tamara; Ortega, Carmelo

2015-01-01

The impact of climate trends during the period 1901–2009 on the life cycle of Hyalomma marginatum in Europe was modeled to assess changes in the physiological processes of this threat to public health. Monthly records of temperature and water vapour at a resolution of 0.5° and equations describing the life cycle processes of the tick were used. The climate in the target region affected the rates of the life cycle processes of H. marginatum: development rates increased, mortality rates in molting stages decreased, and the survival rates of questing ticks decreased in wide territories of the Mediterranean basin. The modeling framework indicated the existence of critical areas in the Balkans, central Europe, and the western coast of France, where the physiological processes of the tick improved to extents that are consistent with the persistence of populations if introduced. A spatially explicit risk assessment was performed to detect candidate areas where active surveys should be performed to monitor changes in tick density or persistence after a hypothetical introduction. We detected areas where the critical abiotic (climate) and biotic (host density) factors overlap, including most of the Iberian peninsula, the Mediterranean coast of France, eastern Turkey, and portions of the western Black Sea region. Wild ungulate densities are unavailable for large regions of the territory, a factor that might affect the outcome of the study. The risk of successfully establishing H. marginatum populations at northern latitudes of its current colonization range seems to be still low, even if the climate has improved the performance of the tick in these areas. PMID:25955315

The Impact of Climate Trends on a Tick Affecting Public Health: A Retrospective Modeling Approach for Hyalomma marginatum (Ixodidae).

PubMed

Estrada-Peña, Agustín; de la Fuente, José; Latapia, Tamara; Ortega, Carmelo

2015-01-01

The impact of climate trends during the period 1901-2009 on the life cycle of Hyalomma marginatum in Europe was modeled to assess changes in the physiological processes of this threat to public health. Monthly records of temperature and water vapour at a resolution of 0.5° and equations describing the life cycle processes of the tick were used. The climate in the target region affected the rates of the life cycle processes of H. marginatum: development rates increased, mortality rates in molting stages decreased, and the survival rates of questing ticks decreased in wide territories of the Mediterranean basin. The modeling framework indicated the existence of critical areas in the Balkans, central Europe, and the western coast of France, where the physiological processes of the tick improved to extents that are consistent with the persistence of populations if introduced. A spatially explicit risk assessment was performed to detect candidate areas where active surveys should be performed to monitor changes in tick density or persistence after a hypothetical introduction. We detected areas where the critical abiotic (climate) and biotic (host density) factors overlap, including most of the Iberian peninsula, the Mediterranean coast of France, eastern Turkey, and portions of the western Black Sea region. Wild ungulate densities are unavailable for large regions of the territory, a factor that might affect the outcome of the study. The risk of successfully establishing H. marginatum populations at northern latitudes of its current colonization range seems to be still low, even if the climate has improved the performance of the tick in these areas.

Cross-species infection trials reveal cryptic parasite varieties and a putative polymorphism shared among host species.

PubMed

Luijckx, Pepijn; Duneau, David; Andras, Jason P; Ebert, Dieter

2014-02-01

A parasite's host range can have important consequences for ecological and evolutionary processes but can be difficult to infer. Successful infection depends on the outcome of multiple steps and only some steps of the infection process may be critical in determining a parasites host range. To test this hypothesis, we investigated the host range of the bacterium Pasteuria ramosa, a Daphnia parasite, and determined the parasites success in different stages of the infection process. Multiple genotypes of Daphnia pulex, Daphnia longispina and Daphnia magna were tested with four Pasteuria genotypes using infection trials and an assay that determines the ability of the parasite to attach to the hosts esophagus. We find that attachment is not specific to host species but is specific to host genotype. This may suggest that alleles on the locus controlling attachment are shared among different host species that diverged 100 million year. However, in our trials, Pasteuria was never able to reproduce in nonnative host species, suggesting that Pasteuria infecting different host species are different varieties, each with a narrow host range. Our approach highlights the explanatory power of dissecting the steps of the infection process and resolves potentially conflicting reports on parasite host ranges. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Intervention, integration and translation in obesity research: Genetic, developmental and metaorganismal approaches

PubMed Central

2011-01-01

Obesity is the focus of multiple lines of inquiry that have -- together and separately -- produced many deep insights into the physiology of weight gain and maintenance. We examine three such streams of research and show how they are oriented to obesity intervention through multilevel integrated approaches. The first research programme is concerned with the genetics and biochemistry of fat production, and it links metabolism, physiology, endocrinology and neurochemistry. The second account of obesity is developmental and draws together epigenetic and environmental explanations that can be embedded in an evolutionary framework. The third line of research focuses on the role of gut microbes in the production of obesity, and how microbial activities interact with host genetics, development and metabolism. These interwoven explanatory strategies are driven by an orientation to intervention, both for experimental and therapeutic outcomes. We connect the integrative and intervention-oriented aspects of obesity research through a discussion of translation, broadening the concept to capture the dynamic, iterative processes of scientific practice and therapy development. This system-oriented analysis of obesity research expands the philosophical scrutiny of contemporary developments in the biosciences and biomedicine, and has the potential to enrich philosophy of science and medicine. PMID:21276254

Pathophysiology of Tumor Neovascularization

PubMed Central

Furuya, Mitsuko; Nishiyama, Mariko; Kasuya, Yoshitoshi; Kimura, Sadao; Ishikura, Hiroshi

2005-01-01

Neovascularization is essential to the process of development and differentiation of tissues in the vertebrate embryo, and is also involved in a wide variety of physiological and pathological conditions in adults, including wound repair, metabolic diseases, inflammation, cardiovascular disorders, and tumor progression. Thanks to cumulative studies on vasculature, new therapeutic approaches have been opened for us to some life-threatening diseases by controlling angiogenesis in the affected organs. In cancer therapy, for example, modulation of factors responsible for tumor angiogenesis may be beneficial in inhibiting of tumor progression. Several antiangiogenic approaches are currently under preclinical trial. However, the mechanisms of neovascularization in tumors are complicated and each tumor shows unique features in its vasculature, depending on tissue specificity, angiogenic micromilieu, grades and stages, host immunity, and so on. For better understanding and effective therapeutic approaches, it is important to clarify both the general mechanism of angiogenic events and the disease-specific mechanism of neovascularization. This review discusses the general features of angiogenesis under physiological and pathological conditions, mainly in tumor progression. In addition, recent topics such as contribution of the endothelial progenitor cells, tumor vasculogenic mimicry, markers for tumor-derived endothelial cells and pericytes, and angiogenic/angiostatic chemokines are summarized. PMID:17315600

A mini review on immune role of chemokines and its receptors in snakehead murrel Channa striatus.

PubMed

Bhatt, Prasanth; Kumaresan, Venkatesh; Palanisamy, Rajesh; Ravichandran, Gayathri; Mala, Kanchana; Amin, S M Nurul; Arshad, Aziz; Yusoff, Fatimah Md; Arockiaraj, Jesu

2018-01-01

Chemokines are ubiquitous cytokine molecules involved in migration of cells during inflammation and normal physiological processes. Though the study on chemokines in mammalian species like humans have been extensively studied, characterization of chemokines in teleost fishes is still in the early stage. The present review provides an overview of chemokines and its receptors in a teleost fish, Channa striatus. C. striatus is an air breathing freshwater carnivore, which has enormous economic importance. This species is affected by an oomycete fungus, Aphanomyces invadans and a Gram negative bacteria Aeromonas hydrophila is known to cause secondary infection. These pathogens impose immune changes in the host organism, which in turn mounts several immune responses. Of these, the role of cytokines in the immune response is immense, due to their involvement in several activities of inflammation such as cell trafficking to the site of inflammation and antigen presentation. Given that importance, chemokines in fishes do have significant role in the immunological and other physiological functions of the organism, hence there is a need to understand the characteristics, activities and performace of these small molecules in details. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mast Cell Function

PubMed Central

da Silva, Elaine Zayas Marcelino; Jamur, Maria Célia

2014-01-01

Since first described by Paul Ehrlich in 1878, mast cells have been mostly viewed as effectors of allergy. It has been only in the past two decades that mast cells have gained recognition for their involvement in other physiological and pathological processes. Mast cells have a widespread distribution and are found predominantly at the interface between the host and the external environment. Mast cell maturation, phenotype and function are a direct consequence of the local microenvironment and have a marked influence on their ability to specifically recognize and respond to various stimuli through the release of an array of biologically active mediators. These features enable mast cells to act as both first responders in harmful situations as well as to respond to changes in their environment by communicating with a variety of other cells implicated in physiological and immunological responses. Therefore, the critical role of mast cells in both innate and adaptive immunity, including immune tolerance, has gained increased prominence. Conversely, mast cell dysfunction has pointed to these cells as the main offenders in several chronic allergic/inflammatory disorders, cancer and autoimmune diseases. This review summarizes the current knowledge of mast cell function in both normal and pathological conditions with regards to their regulation, phenotype and role. PMID:25062998

Chemoprevention in gastrointestinal physiology and disease. Natural products and microbiome.

PubMed

Greiner, Allen K; Papineni, Rao V L; Umar, Shahid

2014-07-01

The human intestinal tract harbors a complex ecosystem of commensal bacteria that play a fundamental role in the well-being of their host. There is a general consensus that diet rich in plant-based foods has many advantages in relation to the health and well-being of an individual. In adults, diets that have a high proportion of fruit and vegetables and a low consumption of meat are associated with a highly diverse microbiota and are defined by a greater abundance of Prevotella compared with Bacteroides, whereas the reverse is associated with a diet that contains a low proportion of plant-based foods. In a philosophical term, our consumption of processed foods, widespread use of antibiotics and disinfectants, and our modern lifestyle may have forever altered our ancient gut microbiome. We may never be able to identify or restore our microbiomes to their ancestral state, but dietary modulation to manipulate specific gut microbial species or groups of species may offer new therapeutic approaches to conditions that are prevalent in modern society, such as functional gastrointestinal disorders, obesity, and age-related nutritional deficiency. We believe that this will become an increasingly important area of health research. Copyright © 2014 the American Physiological Society.

Membrane transport in the malaria parasite and its host erythrocyte.

PubMed

Kirk, Kiaran; Lehane, Adele M

2014-01-01

As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.

Encyrtid parasitoids of soft scale insects: biology, behavior, and their use in biological control.

PubMed

Kapranas, Apostolos; Tena, Alejandro

2015-01-07

Parasitoids of the hymenopterous family Encyrtidae are one of the most important groups of natural enemies of soft scale insects and have been used extensively in biological control. We summarize existing knowledge of the biology, ecology, and behavior of these parasitoids and how it relates to biological control. Soft scale stage/size and phenology are important determinants of host range and host utilization, which are key aspects in understanding how control by these parasitoids is exerted. Furthermore, the nutritional ecology of encyrtids and their physiological interactions with their hosts affect soft scale insect population dynamics. Lastly, the interactions among encyrtids, heteronomous parasitoids, and ants shape parasitoid species complexes and consequently have a direct impact on the biological control of soft scale insects.

The brain's Geppetto-microbes as puppeteers of neural function and behaviour?

PubMed

Stilling, Roman M; Dinan, Timothy G; Cryan, John F

2016-02-01

Research on the microbiome and its interaction with various host organs, including the brain, is increasingly gaining momentum. With more evidence establishing a comprehensive microbiota-gut-brain axis, questions have been raised as to the extent to which microbes influence brain physiology and behaviour. In parallel, there is a growing literature showing active behavioural manipulation in favour of the microbe for certain parasites. However, it seems unclear where the hidden majority of microbes are localised on the parasitism-mutualism spectrum. A long evolutionary history intimately connects host and microbiota, which complicates this classification. In this conceptual minireview, we discuss current hypotheses on host-microbe interaction and argue that novel experimental approaches and theoretical concepts, such as the hologenome theory, are necessary to incorporate transgenerational epigenetic inheritance of the microbiome into evolutionary theories.

Vaccine against autoimmune disease: can helminths or their products provide a therapy?

PubMed

Zaccone, Paola; Cooke, Anne

2013-06-01

There is an increasing interest in exploiting the immunomodulatory effects of helminths and their products in treatment of diseases such as allergy, autoimmunity and inflammatory bowel disease. Detailed examination of the ways in which helminth derived products interact with the host immune system and with host physiology has revealed that these may be multifaceted and have almost certainly arisen following co-evolution of helminths and their hosts. Clinical trials have been initiated with encouraging results in the treatment of inflammatory bowel disease and also Multiple Sclerosis. Identification of key pathways that are manipulated by helminths to ameliorate ongoing inflammatory conditions increases the prospect of developing novel therapies for the treatment and possible prevention of a range of debilitating and life threatening conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

A real-time multi-channel monitoring system for stem cell culture process.

PubMed

Xicai Yue; Drakakis, E M; Lim, M; Radomska, A; Hua Ye; Mantalaris, A; Panoskaltsis, N; Cass, A

2008-06-01

A novel, up to 128 channels, multi-parametric physiological measurement system suitable for monitoring hematopoietic stem cell culture processes and cell cultures in general is presented in this paper. The system aims to measure in real-time the most important physical and chemical culture parameters of hematopoietic stem cells, including physicochemical parameters, nutrients, and metabolites, in a long-term culture process. The overarching scope of this research effort is to control and optimize the whole bioprocess by means of the acquisition of real-time quantitative physiological information from the culture. The system is designed in a modular manner. Each hardware module can operate as an independent gain programmable, level shift adjustable, 16 channel data acquisition system specific to a sensor type. Up to eight such data acquisition modules can be combined and connected to the host PC to realize the whole system hardware. The control of data acquisition and the subsequent management of data is performed by the system's software which is coded in LabVIEW. Preliminary experimental results presented here show that the system not only has the ability to interface to various types of sensors allowing the monitoring of different types of culture parameters. Moreover, it can capture dynamic variations of culture parameters by means of real-time multi-channel measurements thus providing additional information on both temporal and spatial profiles of these parameters within a bioreactor. The system is by no means constrained in the hematopoietic stem cell culture field only. It is suitable for cell growth monitoring applications in general.

Evolution of the rodent eosinophil-associated RNase gene family by rapid gene sorting and positive selection

PubMed Central

Zhang, Jianzhi; Dyer, Kimberly D.; Rosenberg, Helene F.

2000-01-01

The mammalian RNase A superfamily comprises a diverse array of ribonucleolytic proteins that have a variety of biochemical activities and physiological functions. Two rapidly evolving RNases of higher primates are of particular interest as they are major secretory proteins of eosinophilic leukocytes and have been found to possess anti-pathogen activities in vitro. To understand how these RNases acquired this function during evolution and to develop animal models for the study of their functions in vivo, it is necessary to investigate these genes in many species. Here, we report the sequences of 38 functional genes and 23 pseudogenes of the eosinophil-associated RNase (EAR) family from 5 rodent species. Our phylogenetic analysis of these genes showed a clear pattern of evolution by a rapid birth-and-death process and gene sorting, a process characterized by rapid gene duplication and deactivation occurring differentially among lineages. This process ultimately generates distinct or only partially overlapping inventories of the genes, even in closely related species. Positive Darwinian selection also contributed to the diversification of these EAR genes. The striking similarity between the evolutionary patterns of the EAR genes and those of the major histocompatibility complex, immunoglobulin, and T cell receptor genes stands in strong support of the hypothesis that host-defense and generation of diversity are among the primary physiological function of the rodent EARs. The discovery of a large number of divergent EARs suggests the intriguing possibility that these proteins have been specifically tailored to fight against distinct rodent pathogens. PMID:10758160

Behavioural and physiological effects of the trophically transmitted cestode parasite, Cyathocephalus truncatus, on its intermediate host, Gammarus pulex.

PubMed

Franceschi, N; Rigaud, T; Moret, Y; Hervant, F; Bollache, L

2007-11-01

Some parasites with complex life-cycles are able to manipulate the behaviour of their intermediate hosts in a way that increases their transmission to the next host. Gammarids infected by the tapeworm Cyathocephalus truncatus (Cestoda: Spathebothriidea) are known to be more predated by fish than uninfected ones, but potential behavioural manipulation by the parasite has never been investigated. In this study, we tested the hypothesis that C. truncatus is able to manipulate the behaviour of one of its intermediate hosts, Gammarus pulex (Crustacea: Amphipoda). To assess if any behavioural change was linked to other phenotypic alterations, we also measured the immunity of infected and uninfected individuals and investigated the pathogenic effects of the parasite. Infected gammarids were significantly less photophobic than uninfected ones, but no effect of infection on the level of immune defence was found. The results on survival, swimming activity and oxygen consumption suggest that the parasite also has various pathogenic effects. However, the alteration in host phototaxis was not correlated to some of these pathogenic effects. Therefore, we propose that the modification in host reaction to light is a behavioural manipulation, explaining the previously observed increase of gammarid predation rate.

Are sick individuals weak competitors? Competitive ability of snails parasitized by a gigantism-inducing trematode.

PubMed

Seppälä, Otto; Karvonen, Anssi; Kuosa, Marja; Haataja, Maarit; Jokela, Jukka

2013-01-01

Parasitized individuals are often expected to be poor competitors because they are weakened by infections. Many trematode species, however, although extensively exploiting their mollusc hosts, also induce gigantism (increased host size) by diverting host resources towards growth instead of reproduction. In such systems, alternatively to reduced competitive ability due to negative effects of parasitism on host performance, larger size could allow more efficient resource acquisition and thus increase the relative competitive ability of host individuals. We addressed this hypothesis by testing the effect of a trematode parasite Diplostomum pseudospathaceum on the competitive ability of its snail host Lymnaea stagnalis. We experimentally examined the growth of snails kept in pairs in relation to their infection status and intensity of resource competition (i.e. food availability). We found that parasitized snails grew faster and their reproduction was reduced compared to unparasitized individuals indicating parasite-induced gigantism. However, growth of the snails was faster when competing with parasitized individuals compared to unparasitized snails indicating reduced competitive ability due to parasitism. The latter effect, however, was relatively weak suggesting that the effects of the parasite on snail physiology may partly override each other in determining competitive ability.

Are Sick Individuals Weak Competitors? Competitive Ability of Snails Parasitized by a Gigantism-Inducing Trematode

PubMed Central

Seppälä, Otto; Karvonen, Anssi; Kuosa, Marja; Haataja, Maarit; Jokela, Jukka

2013-01-01

Parasitized individuals are often expected to be poor competitors because they are weakened by infections. Many trematode species, however, although extensively exploiting their mollusc hosts, also induce gigantism (increased host size) by diverting host resources towards growth instead of reproduction. In such systems, alternatively to reduced competitive ability due to negative effects of parasitism on host performance, larger size could allow more efficient resource acquisition and thus increase the relative competitive ability of host individuals. We addressed this hypothesis by testing the effect of a trematode parasite Diplostomum pseudospathaceum on the competitive ability of its snail host Lymnaea stagnalis. We experimentally examined the growth of snails kept in pairs in relation to their infection status and intensity of resource competition (i.e. food availability). We found that parasitized snails grew faster and their reproduction was reduced compared to unparasitized individuals indicating parasite-induced gigantism. However, growth of the snails was faster when competing with parasitized individuals compared to unparasitized snails indicating reduced competitive ability due to parasitism. The latter effect, however, was relatively weak suggesting that the effects of the parasite on snail physiology may partly override each other in determining competitive ability. PMID:24205383

DYSMICROBISM, INFLAMMATORY BOWEL DISEASE AND THYROIDITIS: ANALYSIS OF THE LITERATURE.

PubMed

Tomasello, G; Tralongo, P; Amoroso, F; Damiani, P; Sinagra, E; Noto, M; Arculeo, V M; Jurjus Zein, R; Saad, W; Jurjus, A; Gerbino, A; Leone, A

2015-01-01

The human body is colonized by a large number of microbes that are collectively referred to as the microbiota. They interact with the hosting organism and some do contribute to the physiological maintenance of the general good health thru regulation of some metabolic processes while some others are essential for the synthesis of vitamins and short-chain fatty acids. The abnormal variation, in the quality and/or quantity of individual bacterial species residing in the gastro-intestinal tract, is called “dysmicrobism”. The immune system of the host will respond to these changes at the intestinal mucosa level which could lead to Inflammatory Bowel Diseases (IBD). This inflammatory immune response could subsequently extend to other organs and systems outside the digestive tract such as the thyroid, culminating in thyroiditis. The goal of the present study is to review and analyze data reported in the literature about thyroiditis associated with inflammatory bowel diseases such as Ulcerative Colitis (UC) and Crohn’s Disease (CD). It was reported that similarities of some molecular bacterial components with molecular components of the host are considered among the factors causing IBD through an autoimmune reaction which could involve other non-immune cell types. The axis dysmicrobism-IBD-autoimmune reaction will be investigated as a possible etiopathogenic mechanism to Autoimmune Thyroiditis. If such is the case, then the employment of specific probiotic strains may represent a useful approach to moderate the immune system.

Plant natriuretic peptides induce proteins diagnostic for an adaptive response to stress.

PubMed

Turek, Ilona; Marondedze, Claudius; Wheeler, Janet I; Gehring, Chris; Irving, Helen R

2014-01-01

In plants, structural and physiological evidence has suggested the presence of biologically active natriuretic peptides (PNPs). PNPs are secreted into the apoplast, are systemically mobile and elicit a range of responses signaling via cGMP. The PNP-dependent responses include tissue specific modifications of cation transport and changes in stomatal conductance and the photosynthetic rate. PNP also has a critical role in host defense responses. Surprisingly, PNP-homologs are produced by several plant pathogens during host colonization suppressing host defense responses. Here we show that a synthetic peptide representing the biologically active fragment of the Arabidopsis thaliana PNP (AtPNP-A) induces the production of reactive oxygen species in suspension-cultured A. thaliana (Col-0) cells. To identify proteins whose expression changes in an AtPNP-A dependent manner, we undertook a quantitative proteomic approach, employing tandem mass tag (TMT) labeling, to reveal temporal responses of suspension-cultured cells to 1 nM and 10 pM PNP at two different time-points post-treatment. Both concentrations yield a distinct differential proteome signature. Since only the higher (1 nM) concentration induces a ROS response, we conclude that the proteome response at the lower concentration reflects a ROS independent response. Furthermore, treatment with 1 nM PNP results in an over-representation of the gene ontology (GO) terms "oxidation-reduction process," "translation" and "response to salt stress" and this is consistent with a role of AtPNP-A in the adaptation to environmental stress conditions.