共查询到20条相似文献,搜索用时 15 毫秒
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The pseudohypohalous acid hypothiocyanite/hypothiocyanous acid (OSCN−/HOSCN) has been known to play an antimicrobial role in mammalian immunity for decades. It is a potent oxidant that kills bacteria but is non-toxic to human cells. Produced from thiocyanate (SCN−) and hydrogen peroxide (H2O2) in a variety of body sites by peroxidase enzymes, HOSCN has been explored as an agent of food preservation, pathogen killing, and even improved toothpaste. However, despite the well-recognized antibacterial role HOSCN plays in host–pathogen interactions, little is known about how bacteria sense and respond to this oxidant. In this work, we will summarize what is known and unknown about HOSCN in innate immunity and recent advances in understanding the responses that both pathogenic and non-pathogenic bacteria mount against this antimicrobial agent, highlighting studies done with three model organisms, Escherichia coli, Streptococcus spp., and Pseudomonas aeruginosa. 相似文献
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Elise Mazé-Guilmo Géraldine Loot David J. Páez Thierry Lefèvre Simon Blanchet 《Proceedings. Biological sciences / The Royal Society》2014,281(1779)
Hosts have evolved two distinct defence strategies against parasites: resistance (which prevents infection or limit parasite growth) and tolerance (which alleviates the fitness consequences of infection). However, heritable variation in resistance and tolerance and the genetic correlation between these two traits have rarely been characterized in wild host populations. Here, we estimate these parameters for both traits in Leuciscus burdigalensis, a freshwater fish parasitized by Tracheliastes polycolpus. We used a genetic database to construct a full-sib pedigree in a wild L. burdigalensis population. We then used univariate animal models to estimate inclusive heritability (i.e. all forms of genetic and non-genetic inheritance) in resistance and tolerance. Finally, we assessed the genetic correlation between these two traits using a bivariate animal model. We found significant heritability for resistance (H = 17.6%; 95% CI: 7.2–32.2%) and tolerance (H = 18.8%; 95% CI: 4.4–36.1%), whereas we found no evidence for the existence of a genetic correlation between these traits. Furthermore, we confirm that resistance and tolerance are strongly affected by environmental effects. Our results demonstrate that (i) heritable variation exists for parasite resistance and tolerance in wild host populations, and (ii) these traits can evolve independently in populations. 相似文献
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Animesh Gupta Anechelle N. Soto Sarah J. Medina Katherine L. Petrie Justin R. Meyer 《Evolution; international journal of organic evolution》2020,74(4):764-774
An important driver of evolution in viruses is natural selection to optimize the use of their hosts’ genetic network. To learn how viruses respond to this pressure, we disrupted the genetic network of Escherichia coli to inhibit replication of its virus, bacteriophage lambda, and then observed how λ evolved to compensate. We deleted E. coli's dnaJ gene, which lambda uses to initiate DNA replication. Lambda partially restored its ability to reproduce with just two adaptive mutations associated with genes J and S. The location of the mutations was unexpected because they were not in genes that directly interact with DnaJ, rather they affected seemingly unrelated life history traits. A nonsynonymous J mutation increased lambda's adsorption rate and an S regulatory mutation delayed lysis timing. Lambda also recovered some of its reproductive potential through intracellular mutualism. This study offers two important lessons: first, viruses can rapidly adapt to disruptive changes in their host's genetic network. Second, organisms can employ mechanisms thought to operate at the population scale, such as evolution of life history traits and social interactions, in order to overcome hurdles at the molecular level. As life science research progresses and new fields become increasingly specialized, these results remind us of the importance of multiscale and interdisciplinary approaches to understand adaptation. 相似文献
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《Trends in microbiology》2023,31(9):959-971
Bacteroidetes are prevalent in soil ecosystems and are associated with various eukaryotic hosts, including plants, animals, and humans. The ubiquity and diversity of Bacteroidetes exemplify their impressive versatility in niche adaptation and genomic plasticity. Over the past decade, a wealth of knowledge has been obtained on the metabolic functions of clinically relevant Bacteroidetes, but much less attention has been given to Bacteroidetes living in close association with plants. To improve our understanding of the functional roles of Bacteroidetes for plants and other hosts, we review the current knowledge of their taxonomy and ecology, in particular their roles in nutrient cycling and host fitness. We highlight their environmental distribution, stress resilience, genomic diversity, and functional importance in diverse ecosystems, including, but not limited to, plant-associated microbiomes. 相似文献
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Cheryl J. Briggs Roger M. Nisbet William W. Murdoch 《Journal of mathematical biology》1999,38(4):317-345
Continuous-time, age structured, host–parasitoid models exhibit three types of cyclic dynamics: Lotka–Volterra-like consumer-resource
cycles, discrete generation cycles, and “delayed feedback cycles” that occur if the gain to the parasitoid population (defined
by the number of new female parasitoid offspring produced per host attacked) increases with the age of the host attacked.
The delayed feedback comes about in the following way: an increase in the instantaneous density of searching female parasitoids
increases the mortality rate on younger hosts, which reduces the density of future older and more productive hosts, and hence
reduces the future per head recruitment rate of searching female parasitoids. Delayed feedback cycles have previously been
found in studies that assume a step-function for the gain function. Here, we formulate a general host–parasitoid model with
an arbitrary gain function, and show that stable, delayed feedback cycles are a general phenomenon, occurring with a wide
range of gain functions, and strongest when the gain is an accelerating function of host age. We show by examples that locally
stable, delayed feedback cycles commonly occur with parameter values that also yield a single, locally stable equilibrium,
and hence their occurrence depends on initial conditions. A simplified model reveals that the mechanism responsible for the
delayed feedback cycles in our host–parasitoid models is similar to that producing cycles and initial-condition-dependent
dynamics in a single species model with age-dependent cannibalism.
Received: 24 October 1997 / Revised version: 13 June 1998 相似文献
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Scheilla T. Strumillo Denis Kartavykh Fábio F. de Carvalho Jr Nicolly C. Cruz Ana C. de Souza Teodoro Ricardo Sobhie Diaz Marli F. Curcio 《Cell biology international》2021,45(6):1124-1147
With each infectious pandemic or outbreak, the medical community feels the need to revisit basic concepts of immunology to understand and overcome the difficult times brought about by these infections. Regarding viruses, they have historically been responsible for many deaths, and such a peculiarity occurs because they are known to be obligate intracellular parasites that depend upon the host's cell machinery for their replication. Successful infection with the production of essential viral components requires constant viral evolution as a strategy to manipulate the cellular environment, including host internal factors, the host's nonspecific and adaptive immune responses to viruses, the metabolic and energetic state of the infected cell, and changes in the intracellular redox environment during the viral infection cycle. Based on this knowledge, it is fundamental to develop new therapeutic strategies for controlling viral dissemination, by means of antiviral therapies, vaccines, or antioxidants, or by targeting the inhibition or activation of cell signaling pathways or metabolic pathways that are altered during infection. The rapid recovery of altered cellular homeostasis during viral infection is still a major challenge. Here, we review the strategies by which viruses evade the host's immune response and potential tools used to develop more specific antiviral therapies to cure, control, or prevent viral diseases. 相似文献
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Martina Carducci Luana Licata Daniele Peluso Luisa Castagnoli Gianni Cesareni 《Amino acids》2010,38(5):1541-1547
Protein–protein interactions play an essential role in the regulation of most cellular processes. The process of viral infection
is no exception and many viral pathogenic strategies involve targeting and perturbing host–protein interactions. The characterization
of the host protein subnetworks disturbed by invading viruses is a major goal of viral research and may contribute to reveal
fundamental biological mechanisms and to identify new therapeutic strategies. To assist in this approach, we have developed
a database, VirusMINT, which stores in a structured format most of the published interactions between viral and host proteome.
Although SH3 are the most ubiquitous and abundant class of protein binding modules, VirusMINT contains only a few interactions
mediated by this domain class. To overcome this limitation, we have applied the whole interactome scanning experiment approach
to identify interactions between 15 human SH3 domains and viral proline-rich peptides of two oncogenic viruses, human papillomavirus
type 16 and human adenovirus A type 12. This approach identifies 114 new potential interactions between the human SH3 domains
and proline-rich regions of the two viral proteomes. 相似文献
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Variability at human immunodeficiency virus type 1 subtype C protease cleavage sites: an indication of viral fitness? 总被引:3,自引:0,他引:3 下载免费PDF全文
de Oliveira T Engelbrecht S Janse van Rensburg E Gordon M Bishop K zur Megede J Barnett SW Cassol S 《Journal of virology》2003,77(17):9422-9430
Naturally occurring polymorphisms in the protease of human immunodeficiency virus type 1 (HIV-1) subtype C would be expected to lead to adaptive (compensatory) changes in protease cleavage sites. To test this hypothesis, we examined the prevalences and patterns of cleavage site polymorphisms in the Gag, Gag-Pol, and Nef cleavage sites of C compared to those in non-C subtypes. Codon-based maximum-likelihood methods were used to assess the natural selection and evolutionary history of individual cleavage sites. Seven cleavage sites (p17/p24, p24/p2, NC/p1, NC/TFP, PR/RT, RT/p66, and p66/IN) were well conserved over time and in all HIV-1 subtypes. One site (p1/p6(gag)) exhibited moderate variation, and four sites (p2/NC, TFP/p6(pol), p6(pol)/PR, and Nef) were highly variable, both within and between subtypes. Three of the variable sites are known to be major determinants of polyprotein processing and virion production. P2/NC controls the rate and order of cleavage, p6(gag) is an important phosphoprotein required for virion release, and TFP/p6(pol), a novel cleavage site in the transframe domain, influences the specificity of Gag-Pol processing and the activation of protease. Overall, 58.3% of the 12 HIV-1 cleavage sites were significantly more diverse in C than in B viruses. When analyzed as a single concatenated fragment of 360 bp, 96.0% of group M cleavage site sequences fell into subtype-specific phylogenetic clusters, suggesting that they coevolved with the virus. Natural variation at C cleavage sites may play an important role, not only in regulation of the viral cycle but also in disease progression and response to therapy. 相似文献
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《Trends in parasitology》2023,39(7):588-602
The mass production of insects is rapidly expanding globally, supporting multiple industrial needs. However, parasite infections in insect mass-production systems can lower productivity and can lead to devastating losses. High rearing densities and artificial environmental conditions in mass-rearing facilities affect the insect hosts as well as their parasites. Environmental conditions such as temperature, gases, light, vibration, and ionizing radiation can affect productivity in insect mass-production facilities by altering insect development and susceptibility to parasites. This review explores the recent literature on environment–host–parasite interactions with a specific focus on mass-reared insect species. Understanding these complex interactions offers opportunities to optimise environmental conditions for the prevention of infectious diseases in mass-reared insects. 相似文献
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Cristina Llopis-Belenguer Isabel Blasco-Costa Juan Antonio Balbuena Volodimir Sarabeev Daniel B. Stouffer 《Ecography》2020,43(4):559-568
Parasites are often key players in biological invasions since they can mediate the impact of host invasions or can themselves become invasive species. However, the nature and extent of parasite-mediated invasions are often difficult to delineate. Here, we used individual-based, weighted bipartite networks to study the roles (degrees of interactions of individuals in a modular network according to their within- and among-module connections) played by native and invasive host individuals to their parasite communities. We studied two phylogenetically and ecologically close fish species, Mugil cephalus s.l. and Planiliza haematocheilus (Teleostei: Mugilidae). Planiliza haematocheilus is native to the Sea of Japan and invasive in the Sea of Azov whereas, M. cephalus s.l. is native to both seas. Based on the common evolutionary history that drives native host–parasite networks, we hypothesised that 1) native networks have higher modularity than invaded ones; and 2) invasive hosts in the invaded area play a peripheral role to structure parasite communities. We analysed the whole parasite community and subsets based on transmission strategy and host specificity of the parasite species to establish whether modularity and host roles are related to these features in the native and invaded areas. All networks were found to be modular. However, modularity tended to be higher in networks of the native area rather than those of the invaded area. Host individuals of both fish species played similar roles in the native area, whereas invasive hosts played a peripheral role in the networks of the invaded area. We propose that long-term monitoring of the roles of invasive hosts in parasite communities can be a useful proxy for estimating the maturity of the establishment of the invasive hosts in an ecosystem. 相似文献
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Stéphane Cornet Nathalie Franceschi Lo?c Bollache Thierry Rigaud Gabriele Sorci 《Proceedings. Biological sciences / The Royal Society》2009,276(1676):4229-4236
Parasites often manipulate host immunity for their own benefit, either by exacerbating or suppressing the immune response and this may directly affect the expression of parasite virulence. However, genetic variation in immunodepression, which is a prerequisite to its evolution, and the relationship between immunodepression and virulence, have rarely been studied. Here, we investigated the variation among sibships of the acanthocephalan parasite, Pomphorhynchus laevis, in infecting and in immunodepressing its amphipod host, Gammarus pulex. We also assessed the covariation between infectivity, parasite-induced immune depression and host mortality (parasite virulence). We found that infectivity, the intensity of immunodepression and virulence were variable among parasite sibships. Infectivity and the level of immunodepression were not correlated across parasite sibships. Whereas infectivity was unrelated to host mortality, we found that gammarids that were exposed to the parasite sibships that immunodepressed their hosts the most survived better. This positive covariation between host survival and immunodepression suggests that gammarids exposed to the less immunodepressive parasites could suffer from damage imposed by a higher activity of the phenoloxidase. 相似文献
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《Trends in microbiology》2023,31(8):858-871
Insects are one of the most important animal life forms on earth. Symbiotic microbes are closely related to the growth and development of the host insects and can affect pathogen transmission. For decades, various axenic insect-rearing systems have been developed, allowing further manipulation of symbiotic microbiota composition. Here we review the historical development of axenic rearing systems and the latest progress in using axenic and gnotobiotic approaches to study insect–microbe interactions. We also discuss the challenges of these emerging technologies, possible solutions to address these challenges, and future research directions that can contribute to a more comprehensive understanding of insect–microbe interactions. 相似文献
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Joelle Marie Marie-Pierre Simon Axel Kahn 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1982,696(3):340-344
Human fetal liver RNA translated in a rabbit reticulocyte cell-free system directed synthesis of two polypeptides which could be identified by immunological competition as L and L′ pyruvate kinase subunits. Messenger RNAs specifying synthesis of both types of subunits exhibited a sedimentation coefficient of 21–22 S. 相似文献
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The integration of proteomic methods to virology has facilitated a significant breadth of biological insight into mechanisms of virus replication, antiviral host responses and viral subversion of host defenses. Throughout the course of infection, these cellular mechanisms rely heavily on the formation of temporally and spatially regulated virus–host protein–protein interactions. Reviewed here are proteomic-based approaches that have been used to characterize this dynamic virus–host interplay. Specifically discussed are the contribution of integrative mass spectrometry, antibody-based affinity purification of protein complexes, cross-linking and protein array techniques for elucidating complex networks of virus–host protein associations during infection with a diverse range of RNA and DNA viruses. The benefits and limitations of applying proteomic methods to virology are explored, and the contribution of these approaches to important biological discoveries and to inspiring new tractable avenues for the design of antiviral therapeutics is highlighted. 相似文献
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Claudio de Sassi Phillip P. A. Staniczenko Jason M. Tylianakis 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2012,367(1605):3033-3041
Body size is a major factor constraining the trophic structure and functioning of ecological communities. Food webs are known to respond to changes in basal resource abundance, and climate change can initiate compounding bottom-up effects on food-web structure through altered resource availability and quality. However, the effects of climate and co-occurring global changes, such as nitrogen deposition, on the density and size relationships between resources and consumers are unknown, particularly in host–parasitoid food webs, where size structuring is less apparent. We use a Bayesian modelling approach to explore the role of consumer and resource density and body size on host–parasitoid food webs assembled from a field experiment with factorial warming and nitrogen treatments. We show that the treatments increased resource (host) availability and quality (size), leading to measureable changes in parasitoid feeding behaviour. Parasitoids interacted less evenly within their host range and increasingly focused on abundant and high-quality (i.e. larger) hosts. In summary, we present evidence that climate-mediated bottom-up effects can significantly alter food-web structure through both density- and trait-mediated effects. 相似文献
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Ken Yamada Akihiro Ohkubo Yousuke Esaka Takashi Kanamori Yoshiaki Masaki Kohji Seio Mitsuo Sekine 《Bioorganic & medicinal chemistry letters》2013,23(11):3448-3451
To increase base recognition capability and sensitivity, we propose the separation of a commonly used single-probe system for oligonucleotide analysis into a set of three probes: a fluorophore-labeled probe, a promoter probe, and a short probe. In this study, we found that the probes of only 4 nt in length can selectively bind the corresponding gap site on complexes consisting of the target, fluorophore-labeled probe, and promoter probe, exhibiting a more than 14-fold difference in ligation between the matched and mismatched sequences. Moreover, we demonstrated that the immobilized short probes accurately recognized the sequences of the gap sites. 相似文献
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Luigia Pazzagli Camilla Zoppi Lara Carresi Bruno Tiribilli Francesca Sbrana Silvia Schiff Thelma A. Pertinhez Aniello Scala Gianni Cappugi 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009