FIG 3 - available via license: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported
Content may be subject to copyright.
Effect of EsLBP1 on viability of E. coli. Shown are CFU of E. coli strain PL2 after treatment of log-phase culture for 1 h with 30 nM hBPI-21 (Nterminal fragment of human BPI), 30 nM hLBP (human LBP), or 30 nM EsLBP1 or no protein. Error bars indicate SEM of 5 matched biological replicates. Significant differences found by ANOVA and pairwise tests are indicated as follows: **, P 0.01; *, P 0.05.
Source publication
Unlabelled:
Mammalian lipopolysaccharide (LPS) binding proteins (LBPs) occur mainly in extracellular fluids and promote LPS delivery to specific host cell receptors. The function of LBPs has been studied principally in the context of host defense; the possible role of LBPs in nonpathogenic host-microbe interactions has not been well characterized....
Contexts in source publication
Context 1
... does not kill Escherichia coli. The pI of EsLBP1 sug- gests that it more likely functions like LBP and not BPI. To test this hypothesis more directly, we assayed the effects of EsLBP1 and, for comparison, recombinant human LBP and BPI-21 (the LPS- binding and bactericidal N-terminal M r 21,000 fragment of hu- man BPI [37]) on the viability of E. coli. As shown previously (16,17), BPI but not LBP produced killing of E. coli, as manifested by reduced CFU (Fig. 3). At the same protein concentration tested, EsLBP1 had no effect on bacterial viability, resembling mamma- lian ...
Context 2
... For experiments with quantitative comparisons, with the sole exception of comparison of CFU levels (Fig. 3), data were log trans- formed to provide for normality prior to statistical analysis. In the time course experiment, the highest eslbp1 level from each treatment was re- moved as an outlier (Fig. 4A). Comparisons between treatments were made with analysis of variance (ANOVA) (repeated measures ANOVA for CFU), followed by post hoc pairwise comparisons with Tukey multiple comparisons of ...
Context 3
... studies of EsLBP1 show that it is not exclusively a light organ protein but, rather, is abundant in most if not all epithelia (Fig. 6D to F). These data suggest that the light organ has recruited LBP as a protein to signal the presence of a mutualistic partner or control its population rather than to respond to a pathogen. The hypothesized signaling role for EsLBP1 is unproven but is sup- ported by EsLBP1's structural and functional properties, which resemble mammalian LBP more closely than BPI. These features include its predicted near-neutral isoelectric point (28) and the absence of bactericidal activity (Fig. 3), which are distinguishing features of mammalian LBP compared to BPI ...
Similar publications
Interaction of amyloid peptides (Aβ) with receptor for advanced glycation end products (RAGE) elicits an inflammatory response and augments Alzheimer's disease (AD) pathology. The present study was aimed to analyse the interactions of different forms of AΒ42 peptide with ligand binding domain of normal and G82S RAGE and their possible consequences...
Metallo-β-lactamases (MBLs) are zinc ion dependent enzymes that are responsible for the emergence and spread of β-lactam resistance among bacterial pathogens. There are uncharacterized putative MBLs in the environment and their emergence is major interference in the generation of universal MBL inhibitors so it is important to identify and character...
Glyoxalase I (gly I) and Glyoxalase II (gly II), zinc-binding enzymes of the glyoxalase pathway, carry out catabolism of methylglyoxal (MG). Gly II gene cloned from Oryza sativa has been widely used in genetic transformation experiments for salinity tolerance. In the present study, we tried to propose a potential model of the Oryza sativa gly II pr...
Neisseria meningitidis is a facultative pathogen bacterium which is well founded with a number of adhesion molecules to facilitate its colonization in human nasopharynx track. Neisseria meningitidis is a major cause of mortality from severe meningococcal disease and septicemia. Neisseria meningitidis adhesion, NadA, is a trimeric autotransporter ad...
Rabbits (Oryctolagus cuniculus) have been the very frequently used as animal models in the study of human lipid metabolism and atherosclerosis, because they have similar lipoprotein metabolism to humans. Most of hyperlipidemia and atherosclerosis rabbit models are produced by feeding rabbits a high-cholesterol diet. Gene editing or knockout (KO) of...
Citations
... LBP and CD14 have regulatory functions in the innate immune system, whereby both proteins are involved in the recognition of lipopolysaccharide, the major component of the outer membrane of Gram-negative bacteria. LBP brings lipopolysaccharides to the cellular surface of monocytes, where it forms a complex with CD14 [30,31]. LBP correlated with VEGF, indicating an interaction between the two proteins. ...
Purpose
Diabetic macular edema (DME) is a sight-threatening complication of diabetes. Consequently, studying the proteome of DME may provide novel insights into underlying molecular mechanisms.
Methods
In this study, aqueous humor samples from eyes with treatment-naïve clinically significant DME (n = 13) and age-matched controls (n = 11) were compared with label-free liquid chromatography–tandem mass spectrometry. Additional aqueous humor samples from eyes with treatment-naïve DME (n = 15) and controls (n = 8) were obtained for validation by enzyme-linked immunosorbent assay (ELISA). Best-corrected visual acuity (BCVA) was evaluated, and the severity of DME was measured as central subfield thickness (CST) employing optical coherence tomography. Control samples were obtained before cataract surgery. Significantly changed proteins were identified using a permutation-based calculation, with a false discovery rate of 0.05. A human donor eye with DME and a control eye were used for immunofluorescence.
Results
A total of 101 proteins were differentially expressed in the DME. Regulated proteins were involved in complement activation, glycolysis, extracellular matrix interaction, and cholesterol metabolism. The highest-fold change was observed for the fibrinogen alpha chain (fold change = 17.8). Complement components C2, C5, and C8, fibronectin, and hepatocyte growth factor-like protein were increased in DME and correlated with best-corrected visual acuity (BCVA). Ceruloplasmin and complement component C8 correlated with central subfield thickness (CST). Hemopexin, plasma kallikrein, monocyte differentiation antigen CD14 (CD14), and lipopolysaccharide-binding protein (LBP) were upregulated in the DME. LBP was correlated with vascular endothelial growth factor. The increased level of LBP in DME was confirmed using ELISA. The proteins involved in desmosomal integrity, including desmocollin-1 and desmoglein-1, were downregulated in DME and correlated negatively with CST. Immunofluorescence confirmed the extravasation of fibrinogen at the retinal level in the DME.
Conclusion
Elevated levels of pro-inflammatory proteins, including the complement components LBP and CD14, were observed in DME. DME was associated with the loss of basal membrane proteins, compromised desmosomal integrity, and perturbation of glycolysis.
... We were thus able to sketch the morphogenesis of M. galloprovincialis embryos and larvae, demonstrating that developmental progression at the transcriptomic level is closely matched by anatomical changes, at least at the level of ciliated epithelia, musculature and shell growth. Although not novel per se, the combination of transcriptomic data and fluorescent whole-mount staining protocols has so far found only very limited use in surveys of mollusk development (Krasity et al., 2015;Lopez-Anido et al., 2023 preprint;Piovani et al., 2023). The datasets and protocols presented here therefore represent significant advances that will facilitate future studies on bivalve mollusk development and support the establishment of M. galloprovincialis as a model system in developmental biology. ...
A model organism in developmental biology is defined by its experimental amenability and by resources created for the model system by the scientific community. For the most powerful invertebrate models, the combination of both has already yielded a thorough understanding of developmental processes. However, the number of developmental model systems is still limited, and their phylogenetic distribution heavily biased. Members of one of the largest animal lineages, the Spiralia, for example, have long been neglected. In order to remedy this shortcoming, we produced a detailed developmental transcriptome for the bivalve mollusk Mytilus galloprovincialis, and expanded the list of experimental protocols available for this species. Our high-quality transcriptome allowed us to identify transcriptomic signatures of developmental progression and to perform a first comparison with another bivalve mollusk, the Pacific oyster Crassostrea gigas. To allow co-labelling studies, we optimized and combined protocols for immunohistochemistry and hybridization chain reaction to create high-resolution co-expression maps of developmental genes. The resources and protocols described here represent an enormous boost for the establishment of Mytilus galloprovincialis as an alternative model system in developmental biology.
... al. 2015;Tarazona et al. 2019). There has been a recent shift to the use of hybridization chain reaction fluorescent in situ hybridization (HCR-FISH) in cephalopod systems, including the localization of neuronal precursors(Deryckere et al. 2021;Elagoz et al. 2022) and localization of both host and symbiont factors in the bobtail squid light organ(Krasity et al. 2015;Nikolakakis et al. 2015), among other promising studies(Duruz et al. 2022; Gavriouchkina et al. 2022;Styfhals et al. 2022). As HCR-FISH utilizes self-amplifying fluorescent nucleotide hairpins, the technique allows for the cellular or subcellular localization of transcripts(Choi, Schwarzkopf and Pierce 2020). ...
Synopsis
Few animal groups can claim the level of wonder that cephalopods instill in the minds of researchers and the general public. Much of cephalopod biology, however, remains unexplored: the largest invertebrate brain, difficult husbandry conditions, and complex (meta-)genomes, among many other things, have hindered progress in addressing key questions. However, recent technological advancements in sequencing, imaging, and genetic manipulation have opened new avenues for exploring the biology of these extraordinary animals. The cephalopod molecular biology community is thus experiencing a large influx of researchers, emerging from different fields, accelerating the pace of research in this clade. In the first post-pandemic event at the Cephalopod International Advisory Council (CIAC) conference in April 2022, over 40 participants from all over the world met and discussed key challenges and perspectives for current cephalopod molecular biology and evolution. Our particular focus was on the fields of comparative and regulatory genomics, gene manipulation, single-cell transcriptomics, metagenomics, and microbial interactions. This article is a result of this joint effort, summarizing the latest insights from these emerging fields, their bottlenecks, and potential solutions. The article highlights the interdisciplinary nature of the cephalopod-omics community and provides an emphasis on continuous consolidation of efforts and collaboration in this rapidly evolving field.
... Unlike the single bacterial population hosted in the light organ of the bobtail squid (Ruby and Asato, 1993;Nyholm et al., 2002), a complex microbial consortium is hosted in the ANG of some squid and cuttlefish (Pichon et al., 2005;Collins et al., 2012;Kerwin and Nyholm, 2017;Yang et al., 2021). PPRs/PRMs are detected in light organs and hemocytes of the Hawaiian bobtail squid, including five peptidoglycan recognition proteins (Pgrps, Pgrp1-5), a lipopolysaccharide-binding protein (Lbps, Lbp1), and three bactericidal permeability-increasing proteins (Bpis, Bpi2-4) (Kremer et al., 2013;Krasity et al., 2015). In the present study, five Pgrps (Pgrp2-5 and Pgrp3l) and two Bpis (Bpi3 and Bpi3l) were identified in the ANG transcriptome of bigfin reef squid. ...
The bigfin reef squid, Sepioteuthis lessoniana , are a valuable commercial species in East Asian regions such as Taiwan and Japan. A lack of genomic information limits the application of potential aquaculture techniques, especially in breeding when considering the hatching rate of offspring. In some squids and cuttlefishes, symbiotic bacteria are transmitted from the accessory nidamental gland (ANG) to the jelly coat of eggs. In Hawaiian bobtail squid, these parent-delivered mutualistic bacteria play an important role in preventing lethal biofouling of the eggs and accelerating the hatch rate of offspring. The bacterial consortium, which is housed in the female squids ANG, are governed by host selection during female maturation. Immune functions are typically used to explain the regulatory mechanism of symbioses by host selection. In this study, we evaluated the transcripts featured in bacterial selection and maintenance during ANG development using RNA-seq. Different developmental stages of ANGs (stages 1–4) were sequenced. The de novo transcriptome assembly resulted in 524,918 unigenes. Two groups, non-pigmentation group (stage 1 and stage 3) and pigmentation group (stage 4), were clustered by transcriptome-wide expression profile analysis. The gene expression analyses indicated that 9,475 differential expression genes (DEGs) in three different phases and 1,363 (14.3%) DEGs were matched in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Furthermore, KEGG-enriched analysis results suggested that immune responses are a dominant pathway in the non-pigmentation group (stage 1 and stage 3) whereas lipid metabolism and metabolism of flora fermentation are dominant in the pigmentation group (stage 4). Although the host immunity plays an important role during bacterial colonization of the ANG in bigfin reef squid, our results showed that most immune-related genes had a reduced transcriptomic level in the pigmentation group compared with the non-pigmentation group. Therefore, our results provide new insight to understand the regulatory mechanisms of initial bacterial colonization and later bacterial pigmentation in the bigfin reef squid.
... The lipid A component of LPS can bind toll-like receptors (TLRs), mainly TLR4 which can upregulate in ammatory cytokines and chemokines and engage intracellular signaling pathways [11]. When translocated from the gut into the circulation, LPS forms a complex with LPS-binding protein (LBP) which can bind to CD14 on mononuclear cells [12]. This process could increase the production of pro-in ammatory cytokines, such as TNF-α, interleukin-1 (IL-1), and interleukin-6 (IL-6) reducing the in ammatory component of vascular lesions and ultimately resulting in decreased atherosclerosis [13]. ...
Background: To research the associations between gut microbiota composition, lipopolysaccharide (LPS), and atherosclerosis in process of coronary heart disease（CHD）
Methods: We enrolled 50 patients who had been given a traditional coronary angiography diagnosis of coronary heart disease in the CHD group, and 50 matching patients who had CHD excluded in the control group. The CHD patients were further classified into three groups based on their Gensini scores, which were determined using the modified scoring schema: a mild CHD group (26 scores, N=16), a moderate CHD group (26-54 scores, N=23), and a severe CHD group (>54 scores, N=11). The DNA of the gut microbiota was then extracted from their excrement. 16S rRNA sequencing was used to compare the differences in the bacteria between the two groups. BugBase and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) were used to predict the functional composition of the bacteria. In addition, The level of plasma LPS and serum proinflammatory cytokines in the two groups was measured.
Results: Plasma LPS and serum IL-1β, IL-6, and TNF-α concentrations were significantly higher in patients with CHD and significantly different among mild CHDgroup, moderate CHDgroup, and severe CHDgroup(all P＜0.05). There was no difference in the diversity of gut microbiota among the two groups (P＞0.05). At the phylum level, Bacteroidetes were more numerous in the control group. At the genus level, Enterococcus, Butyrivibrio, Dolosigranulum, Pseudomonas, and Anaerotignum were more numerous in the CHD group whereas Enterobacter, Parabacteriodes, Lachnoclostridium, Streptococcus were more numerous in the control group. PICRUSt analysis found that the level of LPS choline phosphotransferase (licD) gene expression and LPS biosynthesis correlated with LPS production was higher in the fecal microbiome of the CHD group(P＜0.05).
Conclusion: The gut microbiota and LPS play a vital role in the development of atherosclerosis through its metabolites, which were anticipated to develop into a CHD diagnostic marker and unique treatment approach.
... In recent years, there has been a concerted effort to discern the effects of the microbiome on apoptosis [37,38] and how this vital form of physiological cell death is altered by microgravity [13,39]. Although E. scolopes has served as a model organism for decades, the pathways by which the symbiont V. fischeri induces apoptotic cell death have not been fully delineated with only a few effectors identified [28,[40][41][42]. The recent sequencing of the E. scolopes genome and reference transcriptome has enabled critical animal pathways, including apoptosis, to be investigated [43]. ...
Background
Spaceflight is a novel and profoundly stressful environment for life. One aspect of spaceflight, microgravity, has been shown to perturb animal physiology thereby posing numerous health risks, including dysregulation of normal developmental pathways. Microgravity can also negatively impact the interactions between animals and their microbiomes. However, the effects of microgravity on developmental processes influenced by beneficial microbes, such as apoptosis, remains poorly understood. Here, the binary mutualism between the bobtail squid, Euprymna scolopes, and the gram-negative bacterium, Vibrio fischeri, was studied under modeled microgravity conditions to elucidate how this unique stressor alters apoptotic cell death induced by beneficial microbes.
Results
Analysis of the host genome and transcriptome revealed a complex network of apoptosis genes affiliated with extrinsic/receptor-mediated and intrinsic/stress-induced apoptosis. Expression of apoptosis genes under modeled microgravity conditions occurred earlier and at high levels compared to gravity controls, in particular the expression of genes encoding initiator and executioner caspases. Functional assays of these apoptotic proteases revealed heightened activity under modeled microgravity; however, these increases could be mitigated using caspase inhibitors.
Conclusions
The outcomes of this study indicated that modeled microgravity alters the expression of both extrinsic and intrinsic apoptosis gene expression and that this process is mediated in part by caspases. Modeled microgravity-associated increases of caspase activity can be pharmacologically inhibited suggesting that perturbations to the normal apoptosis signaling cascade can be mitigated, which may have broader implications for maintaining animal-microbial homeostasis in spaceflight.
... This came as a surprise given that, up to now, the NF-kB has not been identified in any other nematode 103 . Equally surprising was the fact that not only two Toll-like receptors (tol-1 and tol-1like), but also genes encoding for antimicrobial proteins such as a peroxisome assembly factor involved in defense against Gram-(prx-11-like) 104 , a putatively antifungal endochitinase 105 and bactericidal/permeability-increasing proteins (BPIs) were also more abundant in H worms. BPIs may bind LPS and perforate Gram-membranes and have been shown to play a symbiostatic role in other invertebrates 106,107 . However, it is unclear whether activation of the L. oneistus Toll pathway leads to the nuclear NF-kB switching on the expression of antimicrobial genes or whether, as shown in C. elegans, the Toll pathway mediates behavioral avoidance of pathogens 108 . ...
Eukaryotes may experience oxygen deprivation under both physiological and pathological conditions. Because oxygen shortage leads to a reduction in cellular energy production, all eukaryotes studied so far conserve energy by suppressing their metabolism. However, the molecular physiology of animals that naturally and repeatedly experience anoxia is underexplored. One such animal is the marine nematode Laxus oneistus. It thrives, invariably coated by its sulfur-oxidizing symbiont Candidatus Thiosymbion oneisti, in anoxic sulfidic or hypoxic sand. Here, transcriptomics and proteomics showed that, whether in anoxia or not, L. oneistus mostly expressed genes involved in ubiquitination, energy generation, oxidative stress response, immune response, development, and translation. Importantly, ubiquitination genes were also highly expressed when the nematode was subjected to anoxic sulfidic conditions, together with genes involved in autophagy, detoxification and ribosome biogenesis. We hypothesize that these degradation pathways were induced to recycle damaged cellular components (mitochondria) and misfolded proteins into nutrients. Remarkably, when L. oneistus was subjected to anoxic sulfidic conditions, lectin and mucin genes were also upregulated, potentially to promote the attachment of its thiotrophic symbiont. Furthermore, the nematode appeared to survive oxygen deprivation by using an alternative electron carrier (rhodoquinone) and acceptor (fumarate), to rewire the electron transfer chain. On the other hand, under hypoxia, genes involved in costly processes (e.g., amino acid biosynthesis, development, feeding, mating) were upregulated, together with the worm’s Toll-like innate immunity pathway and several immune effectors (e.g., bactericidal/permeability-increasing proteins, fungicides). In conclusion, we hypothesize that, in anoxic sulfidic sand, L. oneistus upregulates degradation processes, rewires the oxidative phosphorylation and reinforces its coat of bacterial sulfur-oxidizers. In upper sand layers, instead, it appears to produce broad-range antimicrobials and to exploit oxygen for biosynthesis and development.
... Each LPS molecule from E. coli has 6-8 negatively charged groups, from phosphates and acid groups in the Lipid A and inner core ( Supplementary Fig. 12b) 35 . Given that human GBP1 lacks the hydrophobic pockets that comprise the LPS binding sites in CD14 and MD-2, we hypothesized that GBP1 binds to LPS by electrostatic interactions, similarly to LBP 36,37 . Consistently, GBP1 binding to LPS micelles was disrupted by incubation with cations (Ca 2+ ), which neutralize the negative charges on LPS 35,38 , or by incubation with polymyxin B, which interacts with the LPS Lipid A and inner core region through ionic and hydrophobic forces, resulting in more monomeric GBP1 and reduced levels of GBP1-LPS association (Fig. 7a and Supplementary Fig. 13). ...
The human non-canonical inflammasome controls caspase-4 activation and gasdermin-D-dependent pyroptosis in response to cytosolic bacterial lipopolysaccharide (LPS). Since LPS binds and oligomerizes caspase-4, the pathway is thought to proceed without dedicated LPS sensors or an activation platform. Here we report that interferon-induced guanylate-binding proteins (GBPs) are required for non-canonical inflammasome activation by cytosolic Salmonella or upon cytosolic delivery of LPS. GBP1 associates with the surface of cytosolic Salmonella seconds after bacterial escape from their vacuole, initiating the recruitment of GBP2-4 to assemble a GBP coat. The GBP coat then promotes the recruitment of caspase-4 to the bacterial surface and caspase activation, in absence of bacteriolysis. Mechanistically, GBP1 binds LPS with high affinity through electrostatic interactions. Our findings indicate that in human epithelial cells GBP1 acts as a cytosolic LPS sensor and assembles a platform for caspase-4 recruitment and activation at LPS-containing membranes as the first step of non-canonical inflammasome signaling. Detection of LPS derived from Gram-negative bacteria by innate immune receptors is a critical step in the host response. Here Santos and colleagues show human GBP1 binds to LPS resulting in non-canonical inflammasome activation.
... Recognition of LPS by Toll like receptor initiates inflammatory responses [33] . Monocytes are involved in the process of inflammation and there is recruitment of especially CD14 monocytes in the lymph nodes 24 hours after the infection [34] . CD14 is a glycosylphosphatidylinositol-anchored membrane glycoprotein, which is expressed in immune cells related to innate immunity. ...
Congestive heart failure (CHF) is defined as a cardiac dysfunction leading to low cardiac output and inadequate tissue perfusion. Intravenous positive inotropes are used to increase myocardial contractility in hospitalized patients with advanced heart failure. Milrinone is a phosphodiesterase Ⅲ inhibitor and used most commonly for inotropic effect. The well-known PROMISE study investigated the effects of milrinone on mortality in patients with severe CHF, and concluded that long-term therapy with milrinone increased morbidity and mortality among patients with advanced CHF. Previous studies have suggested that phosphodiesterase inhibitors can have potential effects on inflammatory pathways. Hence, we hypothesized that milrinone may alter inflammatory gene expressions in cardiomyocytes, thus leading to adverse clinical outcomes. We used rat cardiomyocyte cell line H9C2 and studied the impact of exposing cardiomyocytes to milrinone (10 μmol/L) for 24 hours on inflammatory gene expressions. RNA extracted from cultured cardiomyocytes was used for whole rat genome gene expression assay (41,000 genes). The following changes in inflammatory response-related gene expressions were discovered. Genes with increased expressions included: THBS2 (+9.98), MMP2 (+3.47), DDIT3 (+2.39), and ADORA3 (+3.5). Genes with decreased expressions were: SPP1 (-5.28) and CD14 (-2.05). We found that the above mentioned gene expression changes seem to indicate that milrinone may hinder the inflammatory process which may potentially lead to adverse clinical outcomes. However, further in vivo and clinical investigations will be needed to illustrate the clinical relevance of these gene expression changes induced by milrinone.
... Only the copper ion-binding molecular function was significantly overrepresented in comparison to what was expected (P value adjusted for the false-discovery rate [FDR], Ͻ10 Ϫ4 ). However, the PFAM analysis (Table S4) indicated that a few domains, such as those specific to chitinases (GH20 domain), hemocyanin (multicopper oxidase domain), lipopolysaccharidebinding proteins (LBPs), and bactericidal/permeability-increasing proteins (BPIs), already known to play a role in the establishment of the symbiosis (10,34,35), were overrepresented in both WT-and Δlux mutant-colonized light organs, compared to Apo light organs. For instance, the increased expression of E. scolopes LBP1 in WT-colonized crypts has been implicated in signaling to the host during MAMP-induced regression of the superficial ciliated epithelium (35). ...
... However, the PFAM analysis (Table S4) indicated that a few domains, such as those specific to chitinases (GH20 domain), hemocyanin (multicopper oxidase domain), lipopolysaccharidebinding proteins (LBPs), and bactericidal/permeability-increasing proteins (BPIs), already known to play a role in the establishment of the symbiosis (10,34,35), were overrepresented in both WT-and Δlux mutant-colonized light organs, compared to Apo light organs. For instance, the increased expression of E. scolopes LBP1 in WT-colonized crypts has been implicated in signaling to the host during MAMP-induced regression of the superficial ciliated epithelium (35). ...
A long-term relationship between symbiotic partners is often characterized by development and maturation of host structures that harbor the symbiont cells over the host’s lifetime. To understand the mechanisms involved in symbiosis maintenance more fully, we studied the mature bobtail squid, whose light-emitting organ, under experimental conditions, can be transiently or persistently colonized by Vibrio fischeri or remain uncolonized. Superficial anatomical changes in the organ were largely independent of symbiosis. However, both the microanatomy of cells with which symbionts interact and the patterns of gene expression in the mature animal were due principally to the persistent interactions of host and symbiont cells rather than to a response to early colonization events. Further, the characteristic pronounced daily rhythm on the host transcriptome required persistent V. fischeri colonization of the organ. This experimental study provides a window into how persistent symbiotic colonization influences the form and function of host animal tissues.
