Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.034
Filtrar
1.
Curr Biol ; 34(10): R507-R509, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38772340

RESUMO

Arbuscular mycorrhiza, an ancient symbiosis with soil fungi, support mineral nutrition in most plants. How roots recognize such symbiotic fungi has long been debated. Recent research identifies a Medicago truncatula receptor as a key player in triggering symbiont accommodation responses.


Assuntos
Medicago truncatula , Micorrizas , Simbiose , Simbiose/fisiologia , Medicago truncatula/microbiologia , Medicago truncatula/metabolismo , Medicago truncatula/fisiologia , Micorrizas/fisiologia , Raízes de Plantas/microbiologia , Raízes de Plantas/metabolismo , Luz , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Luz Verde
2.
Sci Rep ; 14(1): 11158, 2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750135

RESUMO

Examples of symbiotic relationships often include cleaning mutualisms, typically involving interactions between cleaner fish and other fish, called the clients. While these cleaners can cooperate by removing ectoparasites from their clients, they can also deceive by feeding on client mucus, a behavior usually referred to as "cheating behavior" that often leads to a discernible jolt from the client fish. Despite extensive studies of these interactions, most research has focused on the visual aspects of the communication. In this study, we aimed to explore the role of acoustic communication in the mutualistic relationship between cleaner fishes and nine holocentrid client species across four regions of the Indo-Pacific Ocean: French Polynesia, Guam, Seychelles, and the Philippines. Video cameras coupled with hydrophones were positioned at various locations on reefs housing Holocentridae fish to observe their acoustic behaviors during interactions. Our results indicate that all nine species of holocentrids can use acoustic signals to communicate to cleaner fish their refusal of the symbiotic interaction or their desire to terminate the cooperation. These sounds were predominantly observed during agonistic behavior and seem to support visual cues from the client. This study provides a novel example of acoustic communication during a symbiotic relationship in teleosts. Interestingly, these vocalizations often lacked a distinct pattern or structure. This contrasts with numerous other interspecific communication systems where clear and distinguishable signals are essential. This absence of a clear acoustic pattern may be because they are used in interspecific interactions to support visual behavior with no selective pressure for developing specific calls required in conspecific recognition. The different sound types produced could also be correlated with the severity of the client response. There is a need for further research into the effects of acoustic behaviors on the quality and dynamics of these mutualistic interactions.


Assuntos
Simbiose , Animais , Simbiose/fisiologia , Peixes/fisiologia , Som , Acústica , Vocalização Animal/fisiologia , Comunicação Animal , Recifes de Corais , Oceano Pacífico , Polinésia , Perciformes/fisiologia
3.
Sci Rep ; 14(1): 10161, 2024 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-38698199

RESUMO

Globally tropical Scleractinian corals have been a focal point for discussions on the impact of a changing climate on marine ecosystems and biodiversity. Research into tropical Scleractinian corals, particularly the role and breakdown of photoendosymbiosis in response to warming, has been prolific in recent decades. However, research into their subtropical, temperate, cold- and deep-water counterparts, whose number is dominated by corals without photoendosymbiosis, has not been as prolific. Approximately 50% of Scleractinian corals (> 700 species) do not maintain photoendosymbiosis and as such, do not rely upon the products of photosynthesis for homeostasis. Some species also have variable partnerships with photendosymbionts depending on life history and ecological niche. Here we undertake a systematic map of literature on Scleractinian corals without, or with variable, photoendosymbiosis. In doing so we identify 482 publications spanning 5 decades. In mapping research effort, we find publications have been sporadic over time, predominately focusing on a limited number of species, with greater research effort directed towards deep-water species. We find only 141 species have been studied, with approximately 30% of the total identified research effort directed toward a single species, Desmophyllum pertusum, highlighting significant knowledge gaps into Scleractinian diversity. We find similar limitations to studied locations, with 78 identified from the global data, of which only few represent most research outputs. We also identified inconsistencies with terminology used to describe Scleractinia without photoendosymbiosis, likely contributing to difficulties in accounting for their role and contribution to marine ecosystems. We propose that the terminology requires re-evaluation to allow further systematic assessment of literature, and to ensure it's consistent with changes implemented for photoendosymbiotic corals. Finally, we find that knowledge gaps identified over 20 years ago are still present for most aphotoendosymbiotic Scleractinian species, and we show data deficiencies remain regarding their function, biodiversity and the impacts of anthropogenic stressors.


Assuntos
Antozoários , Biodiversidade , Simbiose , Antozoários/fisiologia , Animais , Simbiose/fisiologia , Fotossíntese , Ecossistema , Mudança Climática , Recifes de Corais
4.
Plant Physiol Biochem ; 210: 108648, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38653094

RESUMO

This study aims to investigate effects of arbuscular mycorrhizal fungi (AMF) inoculation on nitrogen (N) uptake and assimilation in Populus cathayana under drought stress (DS). Herein, we measured photosynthetic performance, antioxidant enzyme system, N level and N assimilation enzymes, proteins content and distribution, transcripts of genes associated with N uptake or transport in P. cathayana with AMF (AM) or without AMF (NM) under soil water limitation and adequate irrigation. Compared with NM-DS P. cathayana, the growth, gas exchange properties, antioxidant enzyme activities, total N content and the proportion of water-soluble and membrane-bound proteins in AM-DS P. cathayana were increased. Meanwhile, nitrate reductase (NR) activity, NO3- and NO2- concentrations in AM-DS P. cathayana were reduced, while NH4+ concentration, glutamine synthetase (GS) and glutamate synthetase (GOGAT) activities were elevated, indicating that AM symbiosis reduces NO3- assimilation while promoting NH4+ assimilation. Furthermore, the transcriptional levels of NH4+ transporter genes (PcAMT1-4 and PcAMT2-1) and NO3- transporter genes (PcNRT2-1 and PcNRT3-1) in AM-DS P. cathayana roots were significantly down-regulated, as well as NH4+ transporter genes (PcAMT1-6 and PcAMT4-3) in leaves. In AM P. cathayana roots, DS significantly up-regulated the transcriptional levels of RiCPSI and RiURE, the key N transport regulatory genes in AMF compared with adequate irrigation. These results indicated that AM N transport pathway play an essential role on N uptake and utilization in AM P. cathayana to cope with DS. Therefore, this research offers a novel perspective on how AM symbiosis enhances plant resilience to drought at aspect of N acquisition and assimilation.


Assuntos
Secas , Micorrizas , Nitrogênio , Populus , Simbiose , Populus/microbiologia , Populus/metabolismo , Populus/genética , Populus/fisiologia , Micorrizas/fisiologia , Micorrizas/metabolismo , Nitrogênio/metabolismo , Simbiose/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/microbiologia , Raízes de Plantas/metabolismo , Fotossíntese/fisiologia , Resistência à Seca
5.
Mol Biol Cell ; 35(6): ar79, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38598294

RESUMO

The symbiotic relationship between the bioluminescent bacterium Vibrio fischeri and the bobtail squid Euprymna scolopes serves as a valuable system to investigate bacterial growth and peptidoglycan (PG) synthesis within animal tissues. To better understand the growth dynamics of V. fischeri in the crypts of the light-emitting organ of its juvenile host, we showed that, after the daily dawn-triggered expulsion of most of the population, the remaining symbionts rapidly proliferate for ∼6 h. At that point the population enters a period of extremely slow growth that continues throughout the night until the next dawn. Further, we found that PG synthesis by the symbionts decreases as they enter the slow-growing stage. Surprisingly, in contrast to the most mature crypts (i.e., Crypt 1) of juvenile animals, most of the symbiont cells in the least mature crypts (i.e., Crypt 3) were not expelled and, instead, remained in the slow-growing state throughout the day, with almost no cell division. Consistent with this observation, the expression of the gene encoding the PG-remodeling enzyme, L,D-transpeptidase (LdtA), was greatest during the slowly growing stage of Crypt 1 but, in contrast, remained continuously high in Crypt 3. Finally, deletion of the ldtA gene resulted in a symbiont that grew and survived normally in culture, but was increasingly defective in competing against its parent strain in the crypts. This result suggests that remodeling of the PG to generate additional 3-3 linkages contributes to the bacterium's fitness in the symbiosis, possibly in response to stresses encountered during the very slow-growing stage.


Assuntos
Aliivibrio fischeri , Decapodiformes , Peptidoglicano , Simbiose , Simbiose/fisiologia , Aliivibrio fischeri/fisiologia , Aliivibrio fischeri/metabolismo , Animais , Decapodiformes/microbiologia , Decapodiformes/fisiologia , Peptidoglicano/metabolismo , Peptidoglicano/biossíntese , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética
6.
mSystems ; 9(5): e0026124, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38606974

RESUMO

Corals establish symbiotic relationships with microorganisms, especially endosymbiotic photosynthetic algae. Although other microbes have been commonly detected in coral tissues, their identity and beneficial functions for their host are unclear. Here, we confirm the beneficial outcomes of the inoculation of bacteria selected as probiotics and use fluorescence in situ hybridization (FISH) to define their localization in the coral Pocillopora damicornis. Our results show the first evidence of the inherent presence of Halomonas sp. and Cobetia sp. in native coral tissues, even before their inoculation. Furthermore, the relative enrichment of these coral tissue-associated bacteria through their inoculation in corals correlates with health improvements, such as increases in photosynthetic potential, and productivity. Our study suggests the symbiotic status of Halomonas sp. and Cobetia sp. in corals by indicating their localization within coral gastrodermis and epidermis and correlating their increased relative abundance through active inoculation with beneficial outcomes for the holobiont. This knowledge is crucial to facilitate the screening and application of probiotics that may not be transient members of the coral microbiome. IMPORTANCE: Despite the promising results indicating the beneficial outcomes associated with the application of probiotics in corals and some scarce knowledge regarding the identity of bacterial cells found within the coral tissue, the correlation between these two aspects is still missing. This gap limits our understanding of the actual diversity of coral-associated bacteria and whether these symbionts are beneficial. Some researchers, for example, have been suggesting that probiotic screening should only focus on the very few known tissue-associated bacteria, such as Endozoicomonas sp., assuming that the currently tested probiotics are not tissue-associated. Here, we provide specific FISH probes for Halomonas sp. and Cobetia sp., expand our knowledge of the identity of coral-associated bacteria and confirm the probiotic status of the tested probiotics. The presence of these beneficial microorganisms for corals (BMCs) inside host tissues and gastric cavities also supports the notion that direct interactions with the host may underpin their probiotic role. This is a new breakthrough; these results argue against the possibility that the positive effects of BMCs are due to factors that are not related to a direct symbiotic interaction, for example, that the host simply feeds on inoculated bacteria or that the bacteria change the water quality.


Assuntos
Antozoários , Probióticos , Simbiose , Antozoários/microbiologia , Antozoários/fisiologia , Simbiose/fisiologia , Animais , Probióticos/farmacologia , Hibridização in Situ Fluorescente , Halomonas/fisiologia , Microbiota/fisiologia
10.
Sci Rep ; 14(1): 9817, 2024 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684737

RESUMO

Mutualism profoundly affects the morphology and ecological evolution of both hosts and symbionts involved. Heterocyathus is a solitary scleractinian coral that lives on soft substrata, and sipunculan worms live symbiotically in the tube-like cavities (orifice) inside the coral skeletons. This habitat provides protection to the sipunculan worms against predators and-owing to the mobility of the worms-prevents the coral from being buried with sediments. The orifice growth is closely related to the symbiont sipunculan worms; however, this has not been previously elucidated. Here, we clarified the growth process of scleractinian coral orifices and the influence of sipunculan activity on this. The orifices were originally formed by rapid accretion deposits. The coral soft tissue enveloping the growth edge of the orifice repeatedly retreated to the outer side due to direct damage to the soft part and/or excessive stress caused by the rubbing of the sipunculan through locomotion, excretion, and feeding behaviour. This resulted in a toppled-domino microskeletal structure appearance and maintenance of the orifice growth. These outcomes demonstrate the first example of the direct influence of symbionts on the skeletal morphogenesis of scleractinian corals. The mutualism between the two organisms is maintained by the beneficial confrontation in forming orifices.


Assuntos
Antozoários , Simbiose , Animais , Antozoários/fisiologia , Antozoários/crescimento & desenvolvimento , Simbiose/fisiologia , Adaptação Fisiológica , Ecossistema , Recifes de Corais
11.
Mycorrhiza ; 34(1-2): 69-84, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38441669

RESUMO

Trees form symbioses with ectomycorrhizal (ECM) fungi, maintained in part through mutual benefit to both organisms. Our understanding of the signaling events leading to the successful interaction between the two partners requires further study. This is especially true for understanding the role of volatile signals produced by ECM fungi. Terpenoids are a predominant class of volatiles produced by ECM fungi. While several ECM genomes are enriched in the enzymes responsible for the production of these volatiles (i.e., terpene synthases (TPSs)) when compared to other fungi, we have limited understanding of the biochemical products associated with each enzyme and the physiological impact of specific terpenes on plant growth. Using a combination of phylogenetic analyses, RNA sequencing, and functional characterization of five TPSs from two distantly related ECM fungi (Laccaria bicolor and Pisolithus microcarpus), we investigated the role of these secondary metabolites during the establishment of symbiosis. We found that despite phylogenetic divergence, these TPSs produced very similar terpene profiles. We focused on the role of P. microcarpus terpenes and found that the fungus expressed a diverse array of mono-, di-, and sesquiterpenes prior to contact with the host. However, these metabolites were repressed following physical contact with the host Eucalyptus grandis. Exposure of E. grandis to heterologously produced terpenes (enriched primarily in γ -cadinene) led to a reduction in the root growth rate and an increase in P. microcarpus-colonized root tips. These results support a very early putative role of fungal-produced terpenes in the establishment of symbiosis between mycorrhizal fungi and their hosts.


Assuntos
Basidiomycota , Micorrizas , Sesquiterpenos , Micorrizas/fisiologia , Raízes de Plantas/metabolismo , Filogenia , Simbiose/fisiologia , Sesquiterpenos/metabolismo
12.
Plant Physiol Biochem ; 208: 108478, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38430785

RESUMO

Arbuscular mycorrhizal fungi (AMF) can promote plant growth and enhance plant drought tolerance with varying effect size among different fungal species. However, the linkage between the variation and the lipid metabolism, which is exclusively derived from plants, has been little explored thus far. Here, we established AM symbiosis between tomato (Solanum lycopersicum) plants and three AMF species (Rhizophagus intraradices, Funneliformis mosseae, Rhizophagus irregularis) under well watered (WW) or drought stressed (DS) conditions in pot experiment. The plant biomass, chlorophyll fluorescence Fv/Fm, shoot P content and mycorrhizal colonization were determined. Meanwhile, fatty acid (FA) profiles and relative expression of genes encoding for nutrition exchange (SlPT4, SlPT5, RAM2, STR/STR2) in roots were also monitored. DS significantly decreased plant biomass while AMF significantly increased it, with three fungal species varying in their growth promoting capacity and drought tolerance capacity. The growth promoting effect of R. irregularis was lower than those of R. intraradices and F. mosseae, and was associated with higher mycorrhizal colonization and more consumption of lipids. However, the drought tolerance capacity of R. irregularis was greater than those of R. intraradices and F. mosseae, and was associated with less decrease in mycorrhizal colonization and lipid content. We also found that AMF mediated plant drought tolerance via regulating both AM specific FAs and non-AM specific FAs in a complementary manner. These data suggest that lipid metabolism in AM plays a crucial role in plant drought tolerance mediated by AMF.


Assuntos
Micorrizas , Solanum lycopersicum , Micorrizas/fisiologia , Resistência à Seca , Metabolismo dos Lipídeos , Simbiose/fisiologia , Raízes de Plantas/metabolismo
13.
New Phytol ; 242(5): 2207-2222, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38481316

RESUMO

In terrestrial ecosystems, most plant species can form beneficial associations with arbuscular mycorrhizal (AM) fungi. Arbuscular mycorrhizal fungi benefit plant nutrient acquisition and enhance plant tolerance to drought. The high osmolarity glycerol 1 mitogen-activated protein kinase (HOG1-MAPK) cascade genes have been characterized in Rhizophagus irregularis. However, the upstream receptor of the HOG1-MAPK cascade remains to be investigated. We identify the receptor kinase RiSho1 from R. irregularis, containing four transmembrane domains and one Src homology 3 (SH3) domain, corresponding to the homologue of Saccharomyces cerevisiae. Higher expression levels of RiSho1 were detected during the in planta phase in response to drought. RiSho1 protein was localized in the plasma membrane of yeast, and interacted with the HOG1-MAPK module RiPbs2 directly by protein-protein interaction. RiSho1 complemented the growth defect of the yeast mutant ∆sho1 under sorbitol conditions. Knock-down of RiSho1 led to the decreased expression of downstream HOG1-MAPK cascade (RiSte11, RiPbs2, RiHog1) and drought-resistant genes (RiAQPs, RiTPSs, RiNTH1 and Ri14-3-3), hampered arbuscule development and decreased plants antioxidation ability under drought stress. Our study reveals the role of RiSho1 in regulating arbuscule development and drought-resistant genes via the HOG1-MAPK cascade. These findings provide new perspectives on the mechanisms by which AM fungi respond to drought.


Assuntos
Secas , Micorrizas , Simbiose , Micorrizas/fisiologia , Simbiose/genética , Simbiose/fisiologia , Adaptação Fisiológica/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Saccharomyces cerevisiae/genética , Regulação da Expressão Gênica de Plantas , Medicago truncatula/microbiologia , Medicago truncatula/genética , Medicago truncatula/enzimologia , Resistência à Seca , Fungos
14.
Braz J Biol ; 84: e277549, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38511775

RESUMO

In the conducted studies, the moorphological and physiological properties of nodule bacteria of lupine were studied. Lupine plants were grown under the conditions of a microfield experiment on a typical medium loamy urban soil. In the study, a pure culture of Bradyrhizobium lupini was isolated. Then, the morphological properties of nodule bacteria cells and the chemical composition of cell membranes of nodule bacteria were determined. The acid resistance and physiological properties of lupine nodule bacteria were also determined, as well as the ratio of Bradyrhizobium lupini to antibiotics. All studies were carried out according to generally accepted methods. The results of the research showed that during the cultivation of lupine on a typical urban soil, nodule bacteria Bradyrhizobium lupini were isolated, which can be characterized as gram-negative, non-spore-forming rods that do not exhibit amylolytic activity. It was revealed that the rhizobia of nodule bacteria are not acid-resistant. Nodule bacteria turned out to be the least resistant to polymyxin, then to levomycetin, and Bradyrhizobium lupini showed the greatest resistance to tetracycline.


Assuntos
Bradyrhizobium , Lupinus , Rhizobiaceae , Lupinus/microbiologia , Nódulos Radiculares de Plantas/microbiologia , Solo , Bradyrhizobium/fisiologia , Simbiose/fisiologia , Microbiologia do Solo
15.
Int J Mol Sci ; 25(5)2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38474164

RESUMO

The interaction of plants and soil bacteria rhizobia leads to the formation of root nodule symbiosis. The intracellular form of rhizobia, the symbiosomes, are able to perform the nitrogen fixation by converting atmospheric dinitrogen into ammonia, which is available for plants. The symbiosis involves the resource sharing between two partners, but this exchange does not include equivalence, which can lead to resource scarcity and stress responses of one of the partners. In this review, we analyze the possible involvement of the autophagy pathway in the process of the maintenance of the nitrogen-fixing bacteria intracellular colony and the changes in the endomembrane system of the host cell. According to in silico expression analysis, ATG genes of all groups were expressed in the root nodule, and the expression was developmental zone dependent. The analysis of expression of genes involved in the response to carbon or nitrogen deficiency has shown a suboptimal access to sugars and nitrogen in the nodule tissue. The upregulation of several ER stress genes was also detected. Hence, the root nodule cells are under heavy bacterial infection, carbon deprivation, and insufficient nitrogen supply, making nodule cells prone to autophagy. We speculate that the membrane formation around the intracellular rhizobia may be quite similar to the phagophore formation, and the induction of autophagy and ER stress are essential to the success of this process.


Assuntos
Medicago truncatula , Rhizobium , Simbiose/fisiologia , Medicago truncatula/genética , Proteínas de Plantas/genética , Fixação de Nitrogênio/genética , Rhizobium/metabolismo , Autofagia , Nitrogênio/metabolismo , Carbono/metabolismo , Nódulos Radiculares de Plantas/metabolismo
16.
J Evol Biol ; 37(4): 414-428, 2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38366712

RESUMO

Ecological theory suggests that a host organism's internal spatial structure can promote the persistence of mutualistic microbes by allowing for the turnover of tissue occupied by non-beneficial or cheating microbes. This type of regulation, whereby a host preferentially rewards tissue occupied by beneficial members of its microbiome but sanctions tissue occupied by non-beneficial cheaters, is expected to generate a competition-extinction trade-off by allowing beneficial microbes to experience a lower extinction rate than competitively dominant cheaters. Using an adaptive dynamics approach, we demonstrate that although ecologically stable, microbial regulation via sanctioning is not stable in any evolutionary sense, as each individual host will be under pressure to reduce the costs incurred from cheater suppression in order to maximize its own fitness at the expense of the rest of the host population. However, increasing the diversity of non-beneficial cheaters in the host population metamicrobiome can lead to an increase in the relative fitness of hosts that actively sanction non-performing tissue, thus facilitating the evolutionary emergence and persistence of such strategies in host-microbial systems. These counter-intuitive results demonstrate how diversity at multiple levels of biological organization and spatiotemporal scales can interact to facilitate the establishment and maintenance of mutualistic relationships.


Assuntos
Microbiota , Simbiose , Simbiose/fisiologia , Evolução Biológica
17.
Microbiome ; 12(1): 42, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38424629

RESUMO

BACKGROUND: Global warming is causing large-scale disruption of cnidarian-Symbiodiniaceae symbioses fundamental to major marine ecosystems, such as coral reefs. However, the mechanisms by which heat stress perturbs these symbiotic partnerships remain poorly understood. In this context, the upside-down jellyfish Cassiopea has emerged as a powerful experimental model system. RESULTS: We combined a controlled heat stress experiment with isotope labeling and correlative SEM-NanoSIMS imaging to show that host starvation is a central component in the chain of events that ultimately leads to the collapse of the Cassiopea holobiont. Heat stress caused an increase in catabolic activity and a depletion of carbon reserves in the unfed host, concurrent with a reduction in the supply of photosynthates from its algal symbionts. This state of host starvation was accompanied by pronounced in hospite degradation of algal symbionts, which may be a distinct feature of the heat stress response of Cassiopea. Interestingly, this loss of symbionts by degradation was concealed by body shrinkage of the starving animals, resulting in what could be referred to as "invisible" bleaching. CONCLUSIONS: Overall, our study highlights the importance of the nutritional status in the heat stress response of the Cassiopea holobiont. Compared with other symbiotic cnidarians, the large mesoglea of Cassiopea, with its structural sugar and protein content, may constitute an energy reservoir capable of delaying starvation. It seems plausible that this anatomical feature at least partly contributes to the relatively high stress tolerance of these animals in rapidly warming oceans. Video Abstract.


Assuntos
Antozoários , Cnidários , Dinoflagellida , Animais , Ecossistema , Simbiose/fisiologia , Resposta ao Choque Térmico , Recifes de Corais , Dinoflagellida/fisiologia , Antozoários/fisiologia
18.
Sci Rep ; 14(1): 3646, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38351312

RESUMO

The distribution of symbiotic scleractinian corals is driven, in part, by light availability, as host energy demands are partially met through translocation of photosynthate. Physiological plasticity in response to environmental conditions, such as light, enables the expansion of resilient phenotypes in the face of changing environmental conditions. Here we compared the physiology, morphology, and taxonomy of the host and endosymbionts of individual Madracis pharensis corals exposed to dramatically different light conditions based on colony orientation on the surface of a shipwreck at 30 m depth in the Bay of Haifa, Israel. We found significant differences in symbiont species consortia, photophysiology, and stable isotopes, suggesting that these corals can adjust multiple aspects of host and symbiont physiology in response to light availability. These results highlight the potential of corals to switch to a predominantly heterotrophic diet when light availability and/or symbiont densities are too low to sustain sufficient photosynthesis, which may provide resilience for corals in the face of climate change.


Assuntos
Antozoários , Animais , Antozoários/fisiologia , Fotossíntese , Processos Heterotróficos , Simbiose/fisiologia , Israel , Recifes de Corais
19.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38365249

RESUMO

In Burkholderia-Riptortus symbiosis, the host bean bug Riptortus pedestris harbors Burkholderia symbionts in its symbiotic organ, M4 midgut, for use as a nutrient source. After occupying M4, excess Burkholderia symbionts are moved to the M4B region, wherein they are effectively digested and absorbed. Previous studies have shown that M4B has strong symbiont-specific antibacterial activity, which is not because of the expression of antimicrobial peptides but rather because of the expression of digestive enzymes, mainly cathepsin L protease. However, in this study, inhibition of cathepsin L activity did not reduce the bactericidal activity of M4B, indicating that there is an unknown digestive mechanism that renders specifically potent bactericidal activity against Burkholderia symbionts. Transmission electron microscopy revealed that the lumen of symbiotic M4B was filled with a fibrillar matter in contrast to the empty lumen of aposymbiotic M4B. Using chromatographic and electrophoretic analyses, we found that the bactericidal substances in M4B existed as high-molecular-weight (HMW) complexes that were resistant to protease degradation. The bactericidal HMW complexes were visualized on non-denaturing gels using protein- and polysaccharide-staining reagents, thereby indicating that the HMW complexes are composed of proteins and polysaccharides. Strongly stained M4B lumen with Periodic acid-Schiff (PAS) reagent in M4B paraffin sections confirmed HMW complexes with polysaccharide components. Furthermore, M4B smears stained with Periodic acid-Schiff revealed the presence of polysaccharide fibers. Therefore, we propose a key digestive mechanism of M4B: bacteriolytic fibers, polysaccharide fibers associated with digestive enzymes such as cathepsin L, specialized for Burkholderia symbionts in Riptortus gut symbiosis.


Assuntos
Burkholderia , Heterópteros , Animais , Catepsina L/metabolismo , Catepsina L/farmacologia , Simbiose/fisiologia , Ácido Periódico/metabolismo , Ácido Periódico/farmacologia , Insetos , Heterópteros/microbiologia , Bactérias , Polissacarídeos/metabolismo , Burkholderia/fisiologia
20.
Nature ; 626(7998): 271-279, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38326590

RESUMO

Mitochondria retain bacterial traits due to their endosymbiotic origin, but host cells do not recognize them as foreign because the organelles are sequestered. However, the regulated release of mitochondrial factors into the cytosol can trigger cell death, innate immunity and inflammation. This selective breakdown in the 2-billion-year-old endosymbiotic relationship enables mitochondria to act as intracellular signalling hubs. Mitochondrial signals include proteins, nucleic acids, phospholipids, metabolites and reactive oxygen species, which have many modes of release from mitochondria, and of decoding in the cytosol and nucleus. Because these mitochondrial signals probably contribute to the homeostatic role of inflammation, dysregulation of these processes may lead to autoimmune and inflammatory diseases. A potential reason for the increased incidence of these diseases may be changes in mitochondrial function and signalling in response to such recent phenomena as obesity, dietary changes and other environmental factors. Focusing on the mixed heritage of mitochondria therefore leads to predictions for future insights, research paths and therapeutic opportunities. Thus, whereas mitochondria can be considered 'the enemy within' the cell, evolution has used this strained relationship in intriguing ways, with increasing evidence pointing to the recent failure of endosymbiosis being critical for the pathogenesis of inflammatory diseases.


Assuntos
Inflamação , Mitocôndrias , Modelos Biológicos , Simbiose , Humanos , Doenças Autoimunes/etiologia , Doenças Autoimunes/metabolismo , Doenças Autoimunes/patologia , Dieta/efeitos adversos , Homeostase , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Mitocôndrias/fisiologia , Proteínas Mitocondriais/metabolismo , Ácidos Nucleicos/metabolismo , Obesidade/complicações , Obesidade/metabolismo , Obesidade/patologia , Fosfolipídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Simbiose/fisiologia , Animais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...